Combining Sealed & Ported sub - AVS Forum | Home Theater Discussions And Reviews
Forum Jump: 
 45Likes
  • 2 Post By mthomas47
  • 2 Post By Ed Mullen
  • 7 Post By craig john
  • 5 Post By Ed Mullen
  • 1 Post By craig john
  • 1 Post By Ed Mullen
  • 2 Post By craig john
  • 1 Post By Ed Mullen
  • 1 Post By craig john
  • 1 Post By KidHorn
  • 2 Post By Ed Mullen
  • 1 Post By mthomas47
  • 3 Post By Ed Mullen
  • 6 Post By WLC
  • 2 Post By Ed Mullen
  • 2 Post By mthomas47
  • 2 Post By SaskCanesFan
  • 1 Post By mthomas47
  • 3 Post By WLC
 
Thread Tools
post #1 of 22 Old 01-12-2020, 02:12 AM - Thread Starter
Newbie
 
Deeperthandeep's Avatar
 
Join Date: Jan 2020
Posts: 2
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 3 Post(s)
Liked: 0
Combining Sealed & Ported sub

Hey guys,

I’ve slowly been upgrading my home theatre system that started from a Bose Cinemate ii and decided I wanted a true 5.1 setup so now I have an Onkyo TX-SR704 with Polk RtiA7 mains, Polk Csi A4 Center channel, and Polk RtiA3 rears. My current subwoofer is a Polk Audio PSW10.

I’m located in Canada so my vendor options are limited but I had been set on Dual SVS PB-1000 however I now have an opportunity to get a great deal on a used but mint condition SVS SB-3000, which I’ve read is a great sub.

I really was set on a ported box for the low frequency extension Benefits but since this is such a good deal I’m wondering if adding a second sub such as a PB-2000 or PB-3000 would be able to complement the SB-3000 or is it best to stick with the same subwoofers in dual setups? Would a sealed and ported sub work well together?

Thanks in advance eh!
Deeperthandeep is offline  
Sponsored Links
Advertisement
 
post #2 of 22 Old 01-12-2020, 08:52 AM
AVS ***** Member
 
mthomas47's Avatar
 
Join Date: Nov 2007
Posts: 8,497
Mentioned: 380 Post(s)
Tagged: 0 Thread(s)
Quoted: 5672 Post(s)
Liked: 11258
Quote:
Originally Posted by Deeperthandeep View Post
Hey guys,

I’ve slowly been upgrading my home theatre system that started from a Bose Cinemate ii and decided I wanted a true 5.1 setup so now I have an Onkyo TX-SR704 with Polk RtiA7 mains, Polk Csi A4 Center channel, and Polk RtiA3 rears. My current subwoofer is a Polk Audio PSW10.

I’m located in Canada so my vendor options are limited but I had been set on Dual SVS PB-1000 however I now have an opportunity to get a great deal on a used but mint condition SVS SB-3000, which I’ve read is a great sub.

I really was set on a ported box for the low frequency extension Benefits but since this is such a good deal I’m wondering if adding a second sub such as a PB-2000 or PB-3000 would be able to complement the SB-3000 or is it best to stick with the same subwoofers in dual setups? Would a sealed and ported sub work well together?

Thanks in advance eh!

Hi,

It's typically much easier to make identical ported subs work well together, than it is to make ported subs, with different port tunes and different capabilities, work well together. And, it is also typically even more difficult to make ported and sealed subs work together.

Ported subs not only play lower frequencies louder than equivalent sealed subs do, they also offer more low-bass tactile sensations than sealed subs do. Since you are used to that, you may miss it if you switch to a sealed sub. On the other hand, an SB3000 will have a great deal more mid-bass than you have now, and should also give you better overall sound quality. It is a tough decision, especially since your options are more limited in Canada.

Personally, if I really wanted a PB2000, or a PB3000, I would just bite the bullet and buy one. Subs are more expensive in Canada, but good ones aren't exactly cheap anywhere. However, I would not try to combined sealed and ported subs, of whatever brand, and I wouldn't expect to have good results from combining your current Polk sub with one of the SVS ported subs you mentioned. There can always be exceptions, but ported subs typically work best with very similar or identical subs.

Regards,
Mike

GUIDE TO SUBWOOFER CALIBRATION AND BASS PREFERENCES

* The Guide linked above is a comprehensive guide to Audio & HT systems, including:
Speaker placements & Room treatments; HT calibration & Room EQ; Room gain; Bass
Preferences; Subwoofer Buyer's Guide: Sealed/ported; ID subs; Subwoofer placement.
mthomas47 is offline  
post #3 of 22 Old 01-14-2020, 12:20 PM
AVS Forum Special Member
 
Ed Mullen's Avatar
 
Join Date: Nov 2004
Posts: 2,636
Mentioned: 37 Post(s)
Tagged: 0 Thread(s)
Quoted: 421 Post(s)
Liked: 934
Mike is correct - don't mix sealed and ported - typically that will result in some level of phase cancellation (particularly near port tuning) which wouldn't otherwise occur if two identical subs were being used.

Which type of subwoofer is best for your particular application depends on a several variables like your source material, overall playback level, room size and distance to the subwoofer and any lifestyle considerations like size, footprint, visual impact and decor integration.

If you fill in the blanks we can steer you in the right direction. Thanks.

Ed Mullen
Director - Technology and Customer Service
SVS

"What We Do In Life, Echoes In Eternity"
Ed Mullen is offline  
Sponsored Links
Advertisement
 
post #4 of 22 Old 01-14-2020, 03:34 PM
AVS Forum Club Gold
 
craig john's Avatar
 
Join Date: Oct 2003
Location: Lancaster, PA
Posts: 11,867
Mentioned: 69 Post(s)
Tagged: 0 Thread(s)
Quoted: 1384 Post(s)
Liked: 1654
Quote:
Originally Posted by mthomas47 View Post
Hi,

It's typically much easier to make identical ported subs work well together, than it is to make ported subs, with different port tunes and different capabilities, work well together. And, it is also typically even more difficult to make ported and sealed subs work together.
Agreed.

Quote:
Originally Posted by mthomas47 View Post
Ported subs not only play lower frequencies louder than equivalent sealed subs do, they also offer more low-bass tactile sensations than sealed subs do. Since you are used to that, you may miss it if you switch to a sealed sub. On the other hand, an SB3000 will have a great deal more mid-bass than you have now, and should also give you better overall sound quality.
A ported sub will roll-off at 24 dB/octave below F3, (which is usually equivalent to, or slightly below, its' port tune.) A sealed sub will roll of at 12 dB/octave below F3. This is born out by DataBass's groundplane testing. https://data-bass.com/#/articles/5cc...5c88?_k=hfov8k You can also see the same effect in some of the graphs. For example the SVS-PB-13 was measured in 15 Hz mode and sealed mode. Sealed mode has a much slower roll-off than ported. However, roll-off starts about an octave higher in sealed mode.



Because sealed subs roll-off slower, they can work with the inherent "cabin-gain" or "pressure-vessel-gain" of the room to provide deeper in-room extension than ported subs. (For those reading along, Mike has eloquently explained PVG in his thread here: https://www.avsforum.com/forum/113-s...nces.html#VIIB, (Scroll down to Section 3.) The transition point between Modal Response and PVG response happens where the wavelength of a frequency becomes longer than the longest dimension of a room. The room no longer supports modal response. Instead these long wavelengths build pressure in the room. This transition usually occurs somewhere between 20 and 15 Hz in most domestic sized rooms. Also, wall construction and how well the room is sealed play a large role in this. Nonetheless, PVG can add up to 12 dB of gain per octave below the transition point from modal response to PVG response.

Because sealed subs roll off more slowly, they will have a distinct in-room advantage below this transition point. If the sealed sub rolls off at 12 dB/octave and the room adds back 12 dB/octave, these offset each other and the response can remain flat, or even increase slowly below the transition. At one octave below the transition frequency, the room can add back more than the sub rolls off, and the response can actually rise below that point. Of course, sealed subs have less total output than ported subs, so one needs to just keep adding subs until they get the desired total output they are after. IOW, if you want really deep, high output, LF extension into the low teens and single digits, multiple sealed subs is the best way to get that. Ported subs will not use cabin gain nearly as effectively as sealed subs and will not be able to realize the 6 to 12 dB advantage that cabin gain/PVG provides.

Here is an example of what multiple sealed subs can provide by taking advantage of PVG:



(Please note that the scales are very different between these two graphs.)

My 3 sealed subs, (Seaton Sound Submersive HP+'s), each have an F3 of 19 Hz. Yet my in-room response has a flat or slightly rising response to 8 Hz, (where an internal, electronic, 24 dB/octave filter rolls them off much more steeply to protect the drivers from over-excursion.) Nonetheless my subs produce 115 dB in-room at 10 Hz! This is due to room gain and would be very difficult to achieve with ported subs. Ported subs would need to be enormous and have massive drivers and amplification and have HUGE ports to do the same thing. IOW, they're *native* response would need to be flat to 8 to 10 Hz because they can't take advantage of PVG.

Now, of course, many will argue that high output to low frequencies is not necessary. That's certainly a matter of opinion and as we all know, everyone has an opinion. Nonetheless, if the goal of a subwoofer system is high output into the single digits, the best way to get there is with multiple SEALED subwoofers in a sealed room. This is a somewhat different perspective than what Mike said above.

Quote:
Originally Posted by mthomas47 View Post
Personally, if I really wanted a PB2000, or a PB3000, I would just bite the bullet and buy one. Subs are more expensive in Canada, but good ones aren't exactly cheap anywhere. However, I would not try to combined sealed and ported subs, of whatever brand, and I wouldn't expect to have good results from combining your current Polk sub with one of the SVS ported subs you mentioned. There can always be exceptions, but ported subs typically work best with very similar or identical subs.
I completely agree about mixing ported and sealed subs. While it's *possible* to get them to play together, it's difficult to achieve in practice, especially around the port tune of the ported sub.

Having said that, MULTIPLE IDENTICAL subs are virtually always beneficial, and should be considered, whether both subs are ported or or both are sealed. The benefits of multiple subs are not just from the additional output. The primary benefit is from null elimination, (one sub will fill in the nulls of the other sub, and vice versa.) Once the nulls have been reduced or eliminated, EQ can be used to cut the peaks, and smooth, flat response can be achieved across a wide listening area. In the above graph, this is what is occurring from 20 Hz to 80 Hz, (the slightly rising response is due to a change in the target curve induced by a DSP setting in the subs.) .

Craig

Lombardi said it:
"Perfection is not attainable, but if we chase perfection we can catch excellence.
My System

Last edited by craig john; 01-14-2020 at 04:02 PM.
craig john is offline  
post #5 of 22 Old 01-15-2020, 07:28 AM
AVS Forum Special Member
 
Ed Mullen's Avatar
 
Join Date: Nov 2004
Posts: 2,636
Mentioned: 37 Post(s)
Tagged: 0 Thread(s)
Quoted: 421 Post(s)
Liked: 934
Quote:
Originally Posted by craig john View Post
Agreed.

Because sealed subs roll-off slower, they can work with the inherent "cabin-gain" or "pressure-vessel-gain" of the room to provide deeper in-room extension than ported subs. (For those reading along, Mike has eloquently explained PVG in his thread here: https://www.avsforum.com/forum/113-s...nces.html#VIIB, (Scroll down to Section 3.) The transition point between Modal Response and PVG response happens where the wavelength of a frequency becomes longer than the longest dimension of a room. The room no longer supports modal response. Instead these long wavelengths build pressure in the room. This transition usually occurs somewhere between 20 and 15 Hz in most domestic sized rooms. Also, wall construction and how well the room is sealed play a large role in this. Nonetheless, PVG can add up to 12 dB of gain per octave below the transition point from modal response to PVG response.
Great post. My HT room is built like a concrete bunker and has about 18 dB of gain at 10 Hz.

A few corrections/comments:

The modal/pressure transition frequency occurs when the half wavelength becomes longer than the longest dimension in the room.

The transition frequency in a mid-size room typically occurs in the 32-34 Hz region (not 10-15 Hz).

While room gain can in theory be 12 dB/octave in a perfectly rigid and sealed vessel - it is typically 7-9 dB/octave in most real-world rooms due to lossy boundaries and permanent openings.

While a passive sealed sub will roll-off at 12 dB/octave below system resonance (largely dictated by box size and T/S parameters of the driver), the roll-off slope of an active subwoofer can be shaped with EQ and we typically shoot for roll-off onset in the low 30s and a carefully shaped slope in the 15-30 Hz octave consistent with the typical room gain transfer function.

While a passive ported sub will roll-off at 24 dB/octave below port tuning, an active ported sub will typically be high-passed (2nd, 3rd or 4th order) below port tuning, making the roll-off slope more typically 36-48 dB/octave. Even a decent amount of room gain can't save a ported and high-passed sub below port tuning.

Conversely, the problem we see with ported subs in smaller enclosed rooms occurs in the octave above port tuning - where the subwoofer will typically exhibit a rising response in-room in the 34-17 Hz octave, making the subwoofer sound bottom-heavy and lacking balance in the mid-bass. This is why we typically won't recommend a ported sub in a smaller enclosed room, unless there is a auto-EQ system like Audyssey MultEQ XT/XT32 which will restore a flat response in this octave.

Ed Mullen
Director - Technology and Customer Service
SVS

"What We Do In Life, Echoes In Eternity"
Ed Mullen is offline  
post #6 of 22 Old 01-15-2020, 10:45 AM
AVS Forum Club Gold
 
craig john's Avatar
 
Join Date: Oct 2003
Location: Lancaster, PA
Posts: 11,867
Mentioned: 69 Post(s)
Tagged: 0 Thread(s)
Quoted: 1384 Post(s)
Liked: 1654
Quote:
Originally Posted by Ed Mullen View Post
Great post. My HT room is built like a concrete bunker and has about 18 dB of gain at 10 Hz.

A few corrections/comments:

The modal/pressure transition frequency occurs when the half wavelength becomes longer than the longest dimension in the room.

The transition frequency in a mid-size room typically occurs in the 32-34 Hz region (not 10-15 Hz).

While room gain can in theory be 12 dB/octave in a perfectly rigid and sealed vessel - it is typically 7-9 dB/octave in most real-world rooms due to lossy boundaries and permanent openings.

While a passive sealed sub will roll-off at 12 dB/octave below system resonance (largely dictated by box size and T/S parameters of the driver), the roll-off slope of an active subwoofer can be shaped with EQ and we typically shoot for roll-off onset in the low 30s and a carefully shaped slope in the 15-30 Hz octave consistent with the typical room gain transfer function.

While a passive ported sub will roll-off at 24 dB/octave below port tuning, an active ported sub will typically be high-passed (2nd, 3rd or 4th order) below port tuning, making the roll-off slope more typically 36-48 dB/octave. Even a decent amount of room gain can't save a ported and high-passed sub below port tuning.

Conversely, the problem we see with ported subs in smaller enclosed rooms occurs in the octave above port tuning - where the subwoofer will typically exhibit a rising response in-room in the 34-17 Hz octave, making the subwoofer sound bottom-heavy and lacking balance in the mid-bass. This is why we typically won't recommend a ported sub in a smaller enclosed room, unless there is a auto-EQ system like Audyssey MultEQ XT/XT32 which will restore a flat response in this octave.
Thanks for the additional clarifications, Ed. My post was already pretty long and I I left out a lot of that info in an effort to be succinct.


As you stated, the transition point will be determined by the size of the room. A 15' longest dimension would be equivalent to a 1/2 wavelength of 34 Hz. That is a rather small dimension for a "theater." When I said 10 to 15 Hz, I was thinking of a bigger room. However, doing the math, the room would need to be REALLY big to have a transition frequency of 10 to 15 Hz, like 37 feet or more. A 20 Hz frequency has a wavelength of 56 feet, or a 1/2 wavelength of 28 feet, which is the size of the longest dimension of my room. So my room transitions to PVG at about 20 Hz.



The other point about lossy boundaries is worth repeating. It is much more difficult to "pressurize" a room with openings to adjacent spaces. In those cases, PVG will have much less of an impact. Bottom line, PVG works best in a well-sealed room.



Thanks again for chiming in with your well-considered input!


Craig
Adamg (Ret-Navy) likes this.

Lombardi said it:
"Perfection is not attainable, but if we chase perfection we can catch excellence.
My System
craig john is offline  
post #7 of 22 Old 01-15-2020, 03:05 PM
AVS Forum Special Member
 
Ed Mullen's Avatar
 
Join Date: Nov 2004
Posts: 2,636
Mentioned: 37 Post(s)
Tagged: 0 Thread(s)
Quoted: 421 Post(s)
Liked: 934
Quote:
Originally Posted by craig john View Post
Thanks for the additional clarifications, Ed. My post was already pretty long and I I left out a lot of that info in an effort to be succinct.


As you stated, the transition point will be determined by the size of the room. A 15' longest dimension would be equivalent to a 1/2 wavelength of 34 Hz. That is a rather small dimension for a "theater." When I said 10 to 15 Hz, I was thinking of a bigger room. However, doing the math, the room would need to be REALLY big to have a transition frequency of 10 to 15 Hz, like 37 feet or more. A 20 Hz frequency has a wavelength of 56 feet, or a 1/2 wavelength of 28 feet, which is the size of the longest dimension of my room. So my room transitions to PVG at about 20 Hz.



The other point about lossy boundaries is worth repeating. It is much more difficult to "pressurize" a room with openings to adjacent spaces. In those cases, PVG will have much less of an impact. Bottom line, PVG works best in a well-sealed room.



Thanks again for chiming in with your well-considered input!


Craig
While it's not perfect - if you want a pretty decent approximation of the room gain transfer function in your particular room - take a close-mic FR sweep of the woofer cone with the mic a few mm away from the center of the cone. Obviously you'll need to reduce the drive level to prevent overloading the test rig (and make sure the woofer cone doesn't hit the mic).

Then use your graphing software to level match the close-mic FR sweep with your in-room FR sweep over the 40-100 Hz band. The deviation down deep between the close-mic FR sweep and the in-room FR sweep will be a pretty decent approximation of the room gain transfer function.

Close-mic in-room isn't as good as a quasi-anechoic outdoors FR sweep - but it's a fun experiment nonetheless.
Adamg (Ret-Navy) likes this.

Ed Mullen
Director - Technology and Customer Service
SVS

"What We Do In Life, Echoes In Eternity"
Ed Mullen is offline  
post #8 of 22 Old 01-16-2020, 07:25 AM
AVS Forum Club Gold
 
craig john's Avatar
 
Join Date: Oct 2003
Location: Lancaster, PA
Posts: 11,867
Mentioned: 69 Post(s)
Tagged: 0 Thread(s)
Quoted: 1384 Post(s)
Liked: 1654
Quote:
Originally Posted by Ed Mullen View Post
While it's not perfect - if you want a pretty decent approximation of the room gain transfer function in your particular room - take a close-mic FR sweep of the woofer cone with the mic a few mm away from the center of the cone. Obviously you'll need to reduce the drive level to prevent overloading the test rig (and make sure the woofer cone doesn't hit the mic).

Then use your graphing software to level match the close-mic FR sweep with your in-room FR sweep over the 40-100 Hz band. The deviation down deep between the close-mic FR sweep and the in-room FR sweep will be a pretty decent approximation of the room gain transfer function.

Close-mic in-room isn't as good as a quasi-anechoic outdoors FR sweep - but it's a fun experiment nonetheless.
Interesting and enlightening exercise! The following is not exactly what you suggested, but it's pretty close.

Below is an outdoor groundplane measurement of a Seaton Sound Submersive taken by Mark Seaton. Below that is my in-room graph stretched lengthwise to line up the 10 Hz and 200 Hz scale markings.



It's important to note that my in-room graph has Seaton's DSP2 added to it, which is not shown in the GP graph. This adds a boost starting at 40 Hz and gradually increases the boost to 3 dB at 19 Hz. Here is an older close-mic'd graph I did with a different software package that shows what DSP2 does:


(Note that this scale is linear, not logarithmic. Also, there is 1/6th octave smoothing applied to this graph. And unfortunately, when I cropped it, for some reason I cut the scale markings off the bottom. Suffice it say that the divergence starts at 40 Hz and adds 3 dB at 19 Hz.)

Here is a graph of the LP response comparing DSP1 with DSP2:



Here you can clearly see the boost added by the DSP starting at 40 Hz. Nonetheless, even taking DSP 2 into account, it's pretty easy to see that the Pressure Vessel Gain starts somewhere near 35 to 40 Hz in my room... significantly higher than I expected. I learned something new today! Thanks Ed!!!

Craig

Lombardi said it:
"Perfection is not attainable, but if we chase perfection we can catch excellence.
My System
craig john is offline  
post #9 of 22 Old 01-16-2020, 08:21 AM
AVS Forum Special Member
 
Ed Mullen's Avatar
 
Join Date: Nov 2004
Posts: 2,636
Mentioned: 37 Post(s)
Tagged: 0 Thread(s)
Quoted: 421 Post(s)
Liked: 934
If you look at the Submersive's GP FR - you'll note that - relative to the average drive level of ~106 dB in the 40-100 Hz bandwidth, it's -6 dB @ 20 Hz, -13 dB @ 15 Hz and -19 dB @ 10 Hz.

In comparison, your in-room FR (which looks low-passed) - relative to the average drive level of ~86 dB @ 40 Hz is: +0 dB @ 20 Hz and +6 dB @ 10 Hz.

That means, between DSP2 and the room gain transfer function, you are seeing ~6 dB of gain at 20 Hz and ~25 dB of gain at 10 Hz. Subtract out the DSP2 for your actual room gain values.
craig john likes this.

Ed Mullen
Director - Technology and Customer Service
SVS

"What We Do In Life, Echoes In Eternity"
Ed Mullen is offline  
post #10 of 22 Old 01-16-2020, 10:25 AM
AVS Forum Club Gold
 
craig john's Avatar
 
Join Date: Oct 2003
Location: Lancaster, PA
Posts: 11,867
Mentioned: 69 Post(s)
Tagged: 0 Thread(s)
Quoted: 1384 Post(s)
Liked: 1654
Quote:
Originally Posted by Ed Mullen View Post
If you look at the Submersive's GP FR - you'll note that - relative to the average drive level of ~106 dB in the 40-100 Hz bandwidth, it's -6 dB @ 20 Hz, -13 dB @ 15 Hz and -19 dB @ 10 Hz.

In comparison, your in-room FR (which looks low-passed) - relative to the average drive level of ~86 dB @ 40 Hz is: +0 dB @ 20 Hz and +6 dB @ 10 Hz.

That means, between DSP2 and the room gain transfer function, you are seeing ~6 dB of gain at 20 Hz and ~25 dB of gain at 10 Hz. Subtract out the DSP2 for your actual room gain values.
Yes, agreed. My "point" with this whole discussion has been that sealed subs can provide significant ULF response due to the way their roll-off interacts with the inherent PVG found in rooms. It is not uncommon for people to comment that ported subs will have more LF output than sealed. While that is the case in the "native" response of a ported sub, (at least down to port tune), it is definitely not the case in-room below the transition point from modal response to PVG.

Thanks for helping to flush out the details of this somewhat complex and often overlooked phenomenon.

Craig
mthomas47 likes this.

Lombardi said it:
"Perfection is not attainable, but if we chase perfection we can catch excellence.
My System
craig john is offline  
post #11 of 22 Old 01-16-2020, 10:41 AM
AVS Forum Special Member
 
KidHorn's Avatar
 
Join Date: Nov 2003
Location: Derwood, Maryland
Posts: 5,474
Mentioned: 7 Post(s)
Tagged: 0 Thread(s)
Quoted: 1880 Post(s)
Liked: 1298
Optimally you want the subs to be identical. If not, then have similar capabilities. Many people have mixed ported and sealed with great success. All things being equal, for the vast majority of frequencies, ported and sealed will produce the same output. it's only near and below the port tune the slopes change because the port resonates around it's tuning frequency. If you want the best of both worlds, get a dual driver sealed sub.

Generally speaking, sealed are best for small enclosed rooms. Ported are best otherwise.
basshead81 likes this.
KidHorn is offline  
post #12 of 22 Old 01-16-2020, 11:35 AM
AVS Forum Special Member
 
Ed Mullen's Avatar
 
Join Date: Nov 2004
Posts: 2,636
Mentioned: 37 Post(s)
Tagged: 0 Thread(s)
Quoted: 421 Post(s)
Liked: 934
Quote:
Originally Posted by craig john View Post
Yes, agreed. My "point" with this whole discussion has been that sealed subs can provide significant ULF response due to the way their roll-off interacts with the inherent PVG found in rooms. It is not uncommon for people to comment that ported subs will have more LF output than sealed. While that is the case in the "native" response of a ported sub, (at least down to port tune), it is definitely not the case in-room below the transition point from modal response to PVG.

Thanks for helping to flush out the details of this somewhat complex and often overlooked phenomenon.

Craig
Oh definitely!

Think about the amount of amplifier power (in the form of EQ boost) that would be required to mimic a typical room gain transfer function - it's shocking. It's free bass and it adds extension/output far beyond what the quasi-anechoic FR would otherwise suggest. We have plenty of customers using our sealed subs in smaller enclosed rooms with REW plots showing flat extension to 10 Hz (or deeper).

While ported always wins the output race at/above tuning within a given family of subs - sealed can quickly regain the lead below port tuning and provide usable output/extension to extraordinarily deep frequencies.

Ed Mullen
Director - Technology and Customer Service
SVS

"What We Do In Life, Echoes In Eternity"
Ed Mullen is offline  
post #13 of 22 Old 01-16-2020, 01:01 PM
AVS ***** Member
 
mthomas47's Avatar
 
Join Date: Nov 2007
Posts: 8,497
Mentioned: 380 Post(s)
Tagged: 0 Thread(s)
Quoted: 5672 Post(s)
Liked: 11258
Quote:
Originally Posted by craig john View Post
Yes, agreed. My "point" with this whole discussion has been that sealed subs can provide significant ULF response due to the way their roll-off interacts with the inherent PVG found in rooms. It is not uncommon for people to comment that ported subs will have more LF output than sealed. While that is the case in the "native" response of a ported sub, (at least down to port tune), it is definitely not the case in-room below the transition point from modal response to PVG.

Thanks for helping to flush out the details of this somewhat complex and often overlooked phenomenon.

Craig
Quote:
Originally Posted by Ed Mullen View Post
Oh definitely!

Think about the amount of amplifier power (in the form of EQ boost) that would be required to mimic a typical room gain transfer function - it's shocking. It's free bass and it adds extension/output far beyond what the quasi-anechoic FR would otherwise suggest. We have plenty of customers using our sealed subs in smaller enclosed rooms with REW plots showing flat extension to 10 Hz (or deeper).

While ported always wins the output race at/above tuning within a given family of subs - sealed can quickly regain the lead below port tuning and provide usable output/extension to extraordinarily deep frequencies.

I think that this has been a very interesting and beneficial conversation. Without wanting to get too involved in this discussion, though, I do want to add a couple of comments about ported subwoofers. First, in larger rooms (mine is 6000^3 on concrete) it can be more difficult for sealed subs to provide enough firepower <20Hz to be very meaningful.

Second, not everyone likes a flat frequency response, whether it is flat to 10Hz, or to only 15Hz. Many people prefer a rising low-bass response, (AKA the Harman Curve) which requires even more <20Hz output. Actually, according to a number of studies, most people prefer a rising bass response. Personally, for 99.9% of the movies with which I am familiar, I would rather have a strong rising response into the low to mid-teens, than a perfectly flat response at 10Hz or lower.

With low-tuned ported subs, it is perfectly possible to have a strong low-frequency response into the low to mid-teens. Even in my large and heavily-constructed room, PVG starts just about at 15Hz, and coincides quite nicely with the tuning point of my subs. That gives me the opportunity to have a solidly rising response in the low-teens.

The point that I am making here is that there is no one-size-fits-all solution for how to achieve an optimal bass response, because our definition of what is optimal may change depending on room size and construction (concrete floor on earth, versus suspended wood floor, for instance); specific listening content; and personal preferences.

Both sealed and ported subs have inherent advantages. Sealed subs, as noted, have much shallower roll-off characteristics which make them great candidates for smaller rooms and suspended wood floors. That is especially the case when more than two subs can be used to augment the lowest frequencies.

Lower-tuned ported subs, however, often have substantial advantages down into the low to mid-teens, and substantial advantages with respect to ULF TR (tactile response). The latter can be especially helpful on concrete. And, those more powerful subs are typically bought in pairs, rather than in additional multiples.

There is a reason that so many of the ID subwoofer makers have created lower-tuned ported subs in the last few years. That list currently includes SVS, HSU, JTR, PSA, Rythmik, Funk, and even Mark Seaton with his 21" ported model, which is about a 13Hz port tune with one port closed. (Most of the ID makers have settled on port tunes in about the 12 to 14Hz range, although JTR is exclusively 10Hz now.) And, within the AVS community, those low-tuned ported subs are selling like hotcakes. I monitor all of the major ID sub threads.

I just thought it might be helpful to add some additional balance to the discussion, for others who may be reading along.

Regards,
Mike
Adamg (Ret-Navy) likes this.

GUIDE TO SUBWOOFER CALIBRATION AND BASS PREFERENCES

* The Guide linked above is a comprehensive guide to Audio & HT systems, including:
Speaker placements & Room treatments; HT calibration & Room EQ; Room gain; Bass
Preferences; Subwoofer Buyer's Guide: Sealed/ported; ID subs; Subwoofer placement.
mthomas47 is offline  
post #14 of 22 Old 01-16-2020, 01:49 PM - Thread Starter
Newbie
 
Deeperthandeep's Avatar
 
Join Date: Jan 2020
Posts: 2
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 3 Post(s)
Liked: 0
Quote:
Originally Posted by Ed Mullen View Post
Mike is correct - don't mix sealed and ported - typically that will result in some level of phase cancellation (particularly near port tuning) which wouldn't otherwise occur if two identical subs were being used.

Which type of subwoofer is best for your particular application depends on a several variables like your source material, overall playback level, room size and distance to the subwoofer and any lifestyle considerations like size, footprint, visual impact and decor integration.

If you fill in the blanks we can steer you in the right direction. Thanks.


Hey Ed thanks for your reply (and Mike too) i'll try and provide some more info.
I'm uploading pictures of the room but for the measurements are LXW 20X15X7 feet high. The ceiling is "soundproofed".

I sit about 7 Feet from the Sub which is to the left of my left tower.

As far as content goes...I go to electronic bass music festivals across Canada and US and get to experience some of the largest PA setups and it is so damn addicting, I just want to bring some of that experience home....I listen to electronic music primarily, anyone heard of BASSNECTAR? I flex the heaviest and lowest bass music I can find, however I also listen to Pop rock country etc etc to change things up once in a while. I do love to watch movies as well I want to try and experience the LFE that I know I'm missing in my current setup with the PSW10, it does the job but I crave low end.


Playback level varies, I do like it loud however reality is that I am in a basement suite so I can only crank it when my landlord is gone (thankfully that's often).

I guess I'm just wondering if missing a couple HZ below 18 is going to mean missing some of the effects in movies ( SB 3000 drops off at 18 but I have read that the room can extend LFE based on position etc so would that mean I would possibly get a lower frequency response?)
Attached Thumbnails
Click image for larger version

Name:	room 3.jpg
Views:	17
Size:	215.1 KB
ID:	2670880   Click image for larger version

Name:	Room 2.jpg
Views:	13
Size:	179.8 KB
ID:	2670882   Click image for larger version

Name:	Room 1.jpg
Views:	16
Size:	229.1 KB
ID:	2670884  
Deeperthandeep is offline  
post #15 of 22 Old 01-17-2020, 05:50 AM
AVS Forum Special Member
 
Ed Mullen's Avatar
 
Join Date: Nov 2004
Posts: 2,636
Mentioned: 37 Post(s)
Tagged: 0 Thread(s)
Quoted: 421 Post(s)
Liked: 934
Quote:
Originally Posted by mthomas47 View Post
I think that this has been a very interesting and beneficial conversation. Without wanting to get too involved in this discussion, though, I do want to add a couple of comments about ported subwoofers. First, in larger rooms (mine is 6000^3 on concrete) it can be more difficult for sealed subs to provide enough firepower <20Hz to be very meaningful.

Second, not everyone likes a flat frequency response, whether it is flat to 10Hz, or to only 15Hz. Many people prefer a rising low-bass response, (AKA the Harman Curve) which requires even more <20Hz output. Actually, according to a number of studies, most people prefer a rising bass response. Personally, for 99.9% of the movies with which I am familiar, I would rather have a strong rising response into the low to mid-teens, than a perfectly flat response at 10Hz or lower.

With low-tuned ported subs, it is perfectly possible to have a strong low-frequency response into the low to mid-teens. Even in my large and heavily-constructed room, PVG starts just about at 15Hz, and coincides quite nicely with the tuning point of my subs. That gives me the opportunity to have a solidly rising response in the low-teens.

The point that I am making here is that there is no one-size-fits-all solution for how to achieve an optimal bass response, because our definition of what is optimal may change depending on room size and construction (concrete floor on earth, versus suspended wood floor, for instance); specific listening content; and personal preferences.

Both sealed and ported subs have inherent advantages. Sealed subs, as noted, have much shallower roll-off characteristics which make them great candidates for smaller rooms and suspended wood floors. That is especially the case when more than two subs can be used to augment the lowest frequencies.

Lower-tuned ported subs, however, often have substantial advantages down into the low to mid-teens, and substantial advantages with respect to ULF TR (tactile response). The latter can be especially helpful on concrete. And, those more powerful subs are typically bought in pairs, rather than in additional multiples.

There is a reason that so many of the ID subwoofer makers have created lower-tuned ported subs in the last few years. That list currently includes SVS, HSU, JTR, PSA, Rythmik, Funk, and even Mark Seaton with his 21" ported model, which is about a 13Hz port tune with one port closed. (Most of the ID makers have settled on port tunes in about the 12 to 14Hz range, although JTR is exclusively 10Hz now.) And, within the AVS community, those low-tuned ported subs are selling like hotcakes. I monitor all of the major ID sub threads.

I just thought it might be helpful to add some additional balance to the discussion, for others who may be reading along.

Regards,
Mike
Great post and exactly why we offer both types of subwoofers. It's no secret that within a given family, the ported variant can have 2X, 3X even 4X more output (per CEA-2010) in the 18-36 Hz octave.

No amount of room gain can completely offset this advantage in that octave, and in situations where the room is large/open and lossy - and the customer only wants a single subwoofer - ported is often the best solution simply because of its outstanding output linearity over both octaves (18-36 and 40-80).

With that said, ultimately there is nothing ported can do which sealed can't do better - if the user adds enough sealed subwoofers to overcome the inherent output disparity in the 18-36 Hz octave.

Looking at the worst case data point of 20 Hz, it would take about four (4) SB-2000 Pro to achieve the same output at one (1) PB-2000 Pro at 20 Hz. But four (4) SB-2000 Pro stomp a single PB-2000 Pro everywhere else, and offer a denser standing wave pattern and a smoother FR at more locations in the room and also have the potential (in the right type of room) to extend to 10 Hz or deeper.

Four (4) subs for many customers/users is a total non-starter in most systems - so this is just an example for the sake of this particular discussion.

Ed Mullen
Director - Technology and Customer Service
SVS

"What We Do In Life, Echoes In Eternity"
Ed Mullen is offline  
post #16 of 22 Old 01-17-2020, 07:00 AM
WLC
Senior Member
 
WLC's Avatar
 
Join Date: Jan 2006
Location: Westlake, Ohio
Posts: 336
Mentioned: 6 Post(s)
Tagged: 0 Thread(s)
Quoted: 199 Post(s)
Liked: 183
4 Sealed Subs in large room with concrete floor

I have attached a graph showing that compression with my 4 SVS SB16 subs doesn't begin below 20hz until about 108 dbs. We have a large room, 5100^3, that is open in back to the side, with a concrete floor.
This is louder than we normally listen. Our Anthem AVM60 allows us to add 6db rising below 40 hz. Coming from dual powerful ported subs we could not be happier.
I understand that many people are not interested in having 4 subs. Just wanted to show what is possible, at least in our space.
The attached graph includes a PEQ of 2 db at 63 hz

The attached graph does not include the added 6db below 40hz. It is without any additional dbs, except the 2 at 63 hz.
Attached Thumbnails
Click image for larger version

Name:	Compression.jpg
Views:	41
Size:	68.5 KB
ID:	2671198  

Last edited by WLC; 01-17-2020 at 07:06 AM. Reason: Clarification
WLC is offline  
post #17 of 22 Old 01-17-2020, 07:19 AM
AVS Forum Special Member
 
Ed Mullen's Avatar
 
Join Date: Nov 2004
Posts: 2,636
Mentioned: 37 Post(s)
Tagged: 0 Thread(s)
Quoted: 421 Post(s)
Liked: 934
Quote:
Originally Posted by WLC View Post
I have attached a graph showing that compression with my 4 SVS SB16 subs doesn't begin below 20hz until about 108 dbs. We have a large room, 5100^3, that is open in back to the side, with a concrete floor.
This is louder than we normally listen. Our Anthem AVM60 allows us to add 6db rising below 40 hz. Coming from dual powerful ported subs we could not be happier.
I understand that many people are not interested in having 4 subs. Just wanted to show what is possible, at least in our space.
The attached graph includes a PEQ of 2 db at 63 hz

The attached graph does not include the added 6db below 40hz. It is without any additional dbs, except the 2 at 63 hz.
Stellar FR and a perfect example of what is possible with four high-end sealed subs - nicely done.

Ed Mullen
Director - Technology and Customer Service
SVS

"What We Do In Life, Echoes In Eternity"
Ed Mullen is offline  
post #18 of 22 Old 01-17-2020, 08:49 AM
AVS ***** Member
 
mthomas47's Avatar
 
Join Date: Nov 2007
Posts: 8,497
Mentioned: 380 Post(s)
Tagged: 0 Thread(s)
Quoted: 5672 Post(s)
Liked: 11258
Quote:
Originally Posted by Ed Mullen View Post
Great post and exactly why we offer both types of subwoofers. It's no secret that within a given family, the ported variant can have 2X, 3X even 4X more output (per CEA-2010) in the 18-36 Hz octave.

No amount of room gain can completely offset this advantage in that octave, and in situations where the room is large/open and lossy - and the customer only wants a single subwoofer - ported is often the best solution simply because of its outstanding output linearity over both octaves (18-36 and 40-80).

With that said, ultimately there is nothing ported can do which sealed can't do better - if the user adds enough sealed subwoofers to overcome the inherent output disparity in the 18-36 Hz octave.

Looking at the worst case data point of 20 Hz, it would take about four (4) SB-2000 Pro to achieve the same output at one (1) PB-2000 Pro at 20 Hz. But four (4) SB-2000 Pro stomp a single PB-2000 Pro everywhere else, and offer a denser standing wave pattern and a smoother FR at more locations in the room and also have the potential (in the right type of room) to extend to 10 Hz or deeper.

Four (4) subs for many customers/users is a total non-starter in most systems - so this is just an example for the sake of this particular discussion.

Thanks, Ed! I hope you already know, that although I was quoting you and Craig, I honestly don't expect to be telling you anything about subwoofers that you don't already know. The reverse, however, would definitely be true. You could certainly tell me things that I don't know. But, I often write posts for the folks who may be reading along silently, many of whom are usually guests, and who couldn't comment even if they wanted to. For that reason, I want to clarify something that I was saying.

I think that the needle has moved significantly in just the last few years with respect to ported subs. When I speak of low-tuned ported subs, I'm not really referring to the octave from 18Hz to 36Hz. Even the PB16, with its 16Hz tune, which I would characterize as a semi-low-tuned ported subwoofer, has a quasi-anechoic max output of 109dB at 16Hz. Most people who buy the larger subs (especially on AVS, which is the group I am really talking about) would buy duals, for a max quasi-anechoic output of 115dB at 16Hz. And, the subwoofers would still remain quite strong down to at least 14Hz, or so, in-room.

But, there are now a number of genuinely low-tuned ID ported subwoofers on the market, and hundreds of them are being sold every quarter. The needle has definitely moved now! Those subs have port tunes varying from 10Hz to about 13-14Hz. Examples are the Rythmik FV18 and the FV25HP. Soon they will be joined by the dual 18" FV28HP's.

Then, there are the PSA TV3612, TV36 iPal, and the TV42 iPal (dual 21" NEO drivers in a very large cabinet, with a 3800 RMS amp). Those subs were just introduced in 2019. Nathan Funk has recently introduced a 24" driver with a 4800 watt amp, in a very large cabinet, along with potential 18" and 21" variants. All of the subs in the last two paragraphs have port tunes in the 11Hz to 14Hz range.

All of them can deliver really serious SPL down to 12Hz or lower. Several of them can go much lower than that, with room gain augmenting their performance. (As we all know, room gain affects both sealed and ported subs in the same way, as long as there is sufficient SPL at those frequencies to be amplified by room gain.)

And, then there are the JTR ported subs, with their 10Hz port tunes. A single Cap 4000ULF can produce 108dB quasi-anechoically, at 10Hz, and those subs are also most often sold in pairs. Dual Cap 2400ULF's can also produce 108dB quasi-anechoically, and of course, much more than that in-room. And again, they are nearly always sold in pairs. I have a number of AVS friends and acquaintances who have bought those subs.

So, where low-tuned ported subs are concerned, we are no longer talking about the octave between 18Hz and 36Hz. We are seriously talking about the two octaves between 9Hz and 36Hz. Depending on the subs in question, and to some extent on the room volume, dual low-tuned ported subs can legitimately take listeners into good Reference level house curves (rising low-bass) at 10Hz and below. Some listeners can achieve that with just a single large low-tuned ported sub, although for reasons which you understand very well, most of us want dual subs.

In my opinion, this is not just a hypothetical conversation, because on this forum at least, many people are now pursuing very low-frequencies in a way that really wasn't very easy to do at all, even 5 years ago. And, most of the low-tuned ported subwoofer models I listed above have been developed just within the last 3 years.

The curve accelerated exponentially in 2019. PSA alone sold hundreds of the new low-tuned ported subs as soon as they were introduced, with repeated shipments selling-out as soon as they arrived. As I recall, the same thing happened when SVS introduced the new 16 Ultra models in late 2016. As you know, that's when I bought mine. And, Rythmik and Funk both introduced new models, although the Rythmik FV28HP is actually coming in 2020.

There is more demand than ever before for powerful subwoofers, at least on AVS, where people who are really interested in HT may eventually be found. In my experience, most people who upgrade do so in pursuit of lower frequencies, once some basic level of mid-bass performance is achieved.

And, for many people, low-tuned ported subs may be increasingly supplanting sealed subs in the race for very low-frequency performance. The good current crop of low-tuned ported subs can offer at least 115-120dB, quasi-anechoically, for mid-bass frequencies, while beating equivalent sealed subs by very large margins, all the way down to 10-12Hz or even lower. Add in the stronger ULF TR that ported subs can produce within an octave or so of their port tunes, and the combined ULF SPL/TR advantage may become even more pronounced.

Its a very interesting phenomenon, and I have been a little fascinated to watch it unfold over the last few years.

Regards,
Mike

GUIDE TO SUBWOOFER CALIBRATION AND BASS PREFERENCES

* The Guide linked above is a comprehensive guide to Audio & HT systems, including:
Speaker placements & Room treatments; HT calibration & Room EQ; Room gain; Bass
Preferences; Subwoofer Buyer's Guide: Sealed/ported; ID subs; Subwoofer placement.

Last edited by mthomas47; 01-17-2020 at 09:25 AM.
mthomas47 is offline  
post #19 of 22 Old 01-17-2020, 09:09 AM
Member
 
Join Date: Jan 2017
Location: Saskatchewan
Posts: 39
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 41 Post(s)
Liked: 14
I love this thread, and have learned a ton reading it. I had no idea the sheer amount of low end gain available in smaller rooms (and actually larger, as I would call 5100^3 quite large) and that has me re-thinking what I should do when it comes time to flesh out a more complete theatre room. Starting with one ported sub I thought going duals would be perfect, but long term I might be better off selling/moving the ported to another room and investing in multiples of sealed subs instead. The chart WLC posted of a rising response to almost 10HZ looks incredible, and thats a lot bigger room that I would be using. Thanks for all the info from everyone involved!

TV: 65" LG E6 OLED
Receiver: Denon AVR-X3600H
Speakers: Polk RTiA5 fronts, CSiA6 centre, RTiA1 surrounds
Sub: SVS PB-3000
Sony UBP-X800, Xbox One X
SaskCanesFan is offline  
post #20 of 22 Old 01-17-2020, 03:22 PM
AVS ***** Member
 
mthomas47's Avatar
 
Join Date: Nov 2007
Posts: 8,497
Mentioned: 380 Post(s)
Tagged: 0 Thread(s)
Quoted: 5672 Post(s)
Liked: 11258
Quote:
Originally Posted by Deeperthandeep View Post
Hey Ed thanks for your reply (and Mike too) i'll try and provide some more info.
I'm uploading pictures of the room but for the measurements are LXW 20X15X7 feet high. The ceiling is "soundproofed".

I sit about 7 Feet from the Sub which is to the left of my left tower.

As far as content goes...I go to electronic bass music festivals across Canada and US and get to experience some of the largest PA setups and it is so damn addicting, I just want to bring some of that experience home....I listen to electronic music primarily, anyone heard of BASSNECTAR? I flex the heaviest and lowest bass music I can find, however I also listen to Pop rock country etc etc to change things up once in a while. I do love to watch movies as well I want to try and experience the LFE that I know I'm missing in my current setup with the PSW10, it does the job but I crave low end.


Playback level varies, I do like it loud however reality is that I am in a basement suite so I can only crank it when my landlord is gone (thankfully that's often).

I guess I'm just wondering if missing a couple HZ below 18 is going to mean missing some of the effects in movies ( SB 3000 drops off at 18 but I have read that the room can extend LFE based on position etc so would that mean I would possibly get a lower frequency response?)

Hi,

I think that your post got lost a little bit in the overall subwoofer discussion, which is unfortunate since you are the thread starter.

In any event, I will try to respond to it now. You are in an approximately 2100^3 room, which is not especially large, but you are also on concrete. Concrete doesn't transmit tactile sensations very well, and as you have read in earlier posts, TR (tactile response) can be an important aspect of the overall low-bass experience.

That is especially true with the special effects in movies. In fact, below about 20 or 25Hz, it can be quite difficult to separate low-bass sounds and low-bass sensations. They sort of blend together. Ported subs produce much more low-bass TR than sealed subs do. As explained earlier, that is due to the action of the ports and the additional particle velocity they produce.

You will definitely be getting room gain in your room, starting at about 30Hz, but whether it will be enough to make-up for a sealed SB3000's natural roll-off is another question entirely. I bolded some things from your post that still make me believe that you would be better off with a PB3000. An SB3000 doesn't just roll-off at 18Hz, it starts rolling-off at about 50Hz, and that is too high for room gain to help. By the time that you are down to 18Hz, room gain has fallen far behind.

I am adding a link to a page which shows measurements for both the SB3000 and the PB3000. Look at the SB3000 measurements first. You will notice that above 50Hz, the subwoofer is able to play a max level of about 118dB, which is very good. You will also notice that, at 40Hz, the subwoofer has lost about -6dB of output.

https://www.audioholics.com/subwoofe...000/conclusion

That means that at 40Hz, the subwoofer is only playing about half as loud as it was at 63Hz. By 31.5Hz, it has rolled-off by about another -7dB, meaning that it is now only playing less than half as loud as it was at 40Hz, and less than a quarter as loud as it was at 63Hz. By about 31.5Hz, room gain is starting to help, but it won't make-up for a -13dB difference between 63Hz and 31.5Hz. By the time you are down to 20Hz, the SB3000 has lost -24dB compared to what it was able to do at 63Hz. And, room gain can't make all of that up in a 2100^3 room.

The problem actually runs a little deeper than that. We hear bass frequencies in equilibrium with each other, and in equilibrium with frequencies played by our other speakers. If the low-bass frequencies are too soft in relation to the mid-bass frequencies, we simply don't hear them very well, due to the way our hearing works. That is defined by the Equal Loudness Contours. We don't hear low-frequencies as well as those in our normal hearing range of 500Hz to 5,000Hz. And, the problem gets even worse as we drop below about 120Hz, and then below 70Hz. That's why we need subwoofers to begin with.

Further compounding the problem is the fact that most people actually prefer a rising low-bass response, rather than a falling one, as noted in earlier posts. So, even to the extent that room gain could help you to get back to a slightly flatter frequency response, you still might not feel that you were hearing enough low-bass. Most people actually want to hear more low-bass in proportion to mid-bass. That's the same problem you have been facing with your current sub--not enough low-bass in proportion to the mid-bass.

Now, look at the max output table for the PB3000, and compare the differences with the SB3000. See how the PB3000 stays much stronger down to 31.5Hz and below? Room gain can add enough SPL below 31.5Hz to help to equalize the low-bass volume and the mid-bass volume of the PB3000. That is the big advantage of ported subs that Ed was talking about earlier, for the octave between 18Hz and 36Hz (and actually for a half octave above that). We can make-up some of that natural advantage if we add multiple sealed subs, but it may take a lot of them.

For someone who is seriously interested in pushing the bass envelope, and who especially wants more low-bass, a single PB3000 will serve you much better than a single SB3000. And, if you are ever able to add a second sub, I believe that dual PB3000's will still serve you better than dual SB3000's.

If your circumstances and bass preferences were different, my recommendation might be different. But, as it is, I recommend that you buy a PB3000. It is more expensive, but you will be glad that you spent the extra money!

Regards,
Mike
Adamg (Ret-Navy) likes this.

GUIDE TO SUBWOOFER CALIBRATION AND BASS PREFERENCES

* The Guide linked above is a comprehensive guide to Audio & HT systems, including:
Speaker placements & Room treatments; HT calibration & Room EQ; Room gain; Bass
Preferences; Subwoofer Buyer's Guide: Sealed/ported; ID subs; Subwoofer placement.

Last edited by mthomas47; 01-17-2020 at 03:53 PM.
mthomas47 is offline  
post #21 of 22 Old 01-18-2020, 06:52 AM
WLC
Senior Member
 
WLC's Avatar
 
Join Date: Jan 2006
Location: Westlake, Ohio
Posts: 336
Mentioned: 6 Post(s)
Tagged: 0 Thread(s)
Quoted: 199 Post(s)
Liked: 183
Sealed and house curve

Quote:
Originally Posted by SaskCanesFan View Post
I love this thread, and have learned a ton reading it. I had no idea the sheer amount of low end gain available in smaller rooms (and actually larger, as I would call 5100^3 quite large) and that has me re-thinking what I should do when it comes time to flesh out a more complete theatre room. Starting with one ported sub I thought going duals would be perfect, but long term I might be better off selling/moving the ported to another room and investing in multiples of sealed subs instead. The chart WLC posted of a rising response to almost 10HZ looks incredible, and thats a lot bigger room that I would be using. Thanks for all the info from everyone involved!
Thought I would offer further encouragement for consideration of multiple sealed subs if your circumstances permit. I have attached an additional compression graph that includes 6 rising dbs starting at 40 hz of house curve. As you can see, the additional house curve masks the room gain below 20 hz, but you can also see, it is close to flat from about 28 hz down to 10 hz. For reasons that I don't understand, this series of measurements doesn't show compression until about 5 dbs louder: under 20 hz at about 112 db.
My choice of sealed did not include spacial or financial considerations. Both my wife and I do not enjoy rattling or wind blowing in our home theater. By the way, my wife loves our home theater as much as I do and is agreeable to any changes I suggest. The rattling and wind blowing interfere with our "suspension of disbelief". I believe that we can enjoyably play our sealed subs louder than we could our powerful ported subs. Another factor for me is that you cannot tell when the subs are producing the sound. With ported subs, you always knew when they were active. With our sealed, at least in our room, the integration is seamless.
We also purchased 2 PC4000 for our stereo system. We chose those because of spatial limitations. After trying, with Dirac, to integrate them with our main speakers, I ended up plugging the ports and going sealed. Again, this was because with even one port open, you could tell when the subs were active. With them sealed, the sound is seamless.
There are many people on these threads who are much more knowledgeable than I am technically. Mike Thomas and Ed Mullen in particular have been very helpful over the last year in increasing my knowledge so that I could achieve the type of integration with my bass that I am now enjoying. But, since you mentioned thinking about multiple sealed, I thought I would provide additional information.
Good luck whatever you decide.
Attached Thumbnails
Click image for larger version

Name:	compression with 6 db bass.jpg
Views:	26
Size:	66.9 KB
ID:	2671654  
WLC is offline  
post #22 of 22 Old 01-18-2020, 11:09 AM
Member
 
Join Date: Jan 2017
Location: Saskatchewan
Posts: 39
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 41 Post(s)
Liked: 14
Quote:
Originally Posted by WLC View Post
Thought I would offer further encouragement for consideration of multiple sealed subs if your circumstances permit. I have attached an additional compression graph that includes 6 rising dbs starting at 40 hz of house curve. As you can see, the additional house curve masks the room gain below 20 hz, but you can also see, it is close to flat from about 28 hz down to 10 hz. For reasons that I don't understand, this series of measurements doesn't show compression until about 5 dbs louder: under 20 hz at about 112 db.
My choice of sealed did not include spacial or financial considerations. Both my wife and I do not enjoy rattling or wind blowing in our home theater. By the way, my wife loves our home theater as much as I do and is agreeable to any changes I suggest. The rattling and wind blowing interfere with our "suspension of disbelief". I believe that we can enjoyably play our sealed subs louder than we could our powerful ported subs. Another factor for me is that you cannot tell when the subs are producing the sound. With ported subs, you always knew when they were active. With our sealed, at least in our room, the integration is seamless.
We also purchased 2 PC4000 for our stereo system. We chose those because of spatial limitations. After trying, with Dirac, to integrate them with our main speakers, I ended up plugging the ports and going sealed. Again, this was because with even one port open, you could tell when the subs were active. With them sealed, the sound is seamless.
There are many people on these threads who are much more knowledgeable than I am technically. Mike Thomas and Ed Mullen in particular have been very helpful over the last year in increasing my knowledge so that I could achieve the type of integration with my bass that I am now enjoying. But, since you mentioned thinking about multiple sealed, I thought I would provide additional information.
Good luck whatever you decide.
Thanks for the additional info, and showing what's possible with the right setup! To be clear, this is purely academic for now, any actual setup like that would be a few years away at least. I've barely had my current system for 3 weeks, and with a young family and coming house upgrade, there's a lot of things to cover first before really diving into the theatre room. But I still like learning as much as I can so I can plan ahead and do things properly for when the time comes. I know I'll want to expand my current speakers to a 7.x.4 Atmos setup, and my single PB3000 hasn't left me wanting at all so far, I'm very happy, so going to duals may be more sub than I'll ever need. But I'm also a horrible person for wondering what if, and a site like this doesn't help lol. Knowing that systems like yours and some of the DIY stuff exist, its easy to get upgrade fever and make the mental jump from 2 13's to 4 16's or 18's in a hurry. May have to see if I can find a system as capable as yours within a couple hours drive at some point in the future and see what I think of experiencing it first hand.

TV: 65" LG E6 OLED
Receiver: Denon AVR-X3600H
Speakers: Polk RTiA5 fronts, CSiA6 centre, RTiA1 surrounds
Sub: SVS PB-3000
Sony UBP-X800, Xbox One X
SaskCanesFan is offline  
Sponsored Links
Advertisement
 
Reply Subwoofers, Bass, and Transducers

Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page


Forum Jump: 

Posting Rules  
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off