UM18-22, Sealed versus Vented, why? - AVS Forum | Home Theater Discussions And Reviews
Forum Jump: 
 52Likes
Reply
 
Thread Tools
post #1 of 53 Old 06-23-2020, 10:57 PM - Thread Starter
Member
 
-Pjackso's Avatar
 
Join Date: Dec 2003
Posts: 169
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 5 Post(s)
Liked: 10
UM18-22, Sealed versus Vented, why?

Hi all,
First off, I haven't built any speaker projects for over 20 years. So I'm waaay behind the curve on the new advances and tricks of speaker building.
PLEASE - I am more then open to build recommendations and insight.

Don't know why, but I got the urge to build a subwoofer project.
I tried to talk myself out of it, ...but here I am.


I dove in and did a lot of reading on what other people were recommending, and I decided to use the UM18-22 driver.
During my research I read countless threads of people buying the 4.0 cu ft cabinet from PE, and claim they're ecstatic with the results.
Although, when I plug the driver into WinISD with a 4.0 sealed cabinet - the graph doesn't seem impressive - when compared to vented.


Vented enclosures provide a large advantage in the bottom end.
See the WinISD SPL model for my point:

Blue is the 4.0 cu ft sealed box.
Red is 14 cu ft vented, and the green is various sizes of vented cabinets for comparison.
(All are powered at 500W. All vented cabinets have a high-pass 13hz filter)

The 14 cu ft vented cabinet (red line) has a 9db advantage over the 4.0 cu ft sealed cabinet (blue line) at 20 hz.
A 9 db advantage at 20 hz!!!!!! That's huge!!! And the F3 drop-off goes from (28 hz, sealed) down to (15 hz, vented).
And that's *without* any amplifier low-end boost compensation.


The cone excursion is fine, and port velocity stays within the 110 ft/s recommended limit (for 14 cu ft cabinet - or smaller).



So what gives?

Based on the WinISD outputs, why would someone choose sealed over vented?
I understand the PE flat-pack cabinet is easy to assemble and relatively small. (Easy, Simple, and good WAF)
The downside to vented cabinets are that they are much larger. Is the cabinet size the only reason?


How do the sealed cabinet folks compensate for such a drastic disadvantage?





Thanks in advance.
Attached Thumbnails
Click image for larger version

Name:	UM18-22 vented, SPL, summary view.png
Views:	135
Size:	87.9 KB
ID:	2747898   Click image for larger version

Name:	UM18-22 vented, Cone Excursion, summary view.png
Views:	91
Size:	94.9 KB
ID:	2747906   Click image for larger version

Name:	UM18-22 vented, Rear Port Air velocity, summary view.png
Views:	89
Size:	76.5 KB
ID:	2747908  

-Nothing relevant to add.

Last edited by -Pjackso; 06-23-2020 at 11:06 PM.
-Pjackso is offline  
Sponsored Links
Advertisement
 
post #2 of 53 Old 06-24-2020, 01:32 AM
AVS Forum Special Member
 
A9X-308's Avatar
 
Join Date: Mar 2008
Location: Australia
Posts: 8,738
Mentioned: 35 Post(s)
Tagged: 0 Thread(s)
Quoted: 2035 Post(s)
Liked: 1751
Quote:
Originally Posted by -Pjackso View Post
So what gives?

Based on the WinISD outputs, why would someone choose sealed over vented?
I understand the PE flat-pack cabinet is easy to assemble and relatively small. (Easy, Simple, and good WAF)
The downside to vented cabinets are that they are much larger. Is the cabinet size the only reason?


How do the sealed cabinet folks compensate for such a drastic disadvantage?
Thanks in advance.
Sealed will almost always be smaller than ported and that may be needed in a given space. EQ and power as well as careful placement, using multiples etc can make up for it. Typically sealed speakers roll of in the LF at a slower rate, 12dB/oct and cabin gain in smaller rooms will bring up the low end so less EQ and power is needed.


Ported have an advantage in the fairly narrow bandwidth of the Helmholtz resonance; they are NOT more efficient than sealed, except in this narrow BW. They're larger physically, roll off at a faster rate, 24dB/oct and they really need an electrical 2nd order filter below tune to ensure that the driver does not go into over excursion with loud signal below the tune of the enclosure. Do this and you have an effective 36dB/oct roll off, so can have a narrower useful bandwidth. There's lots below 20Hz in a lot of mainly action movies.

“You are not special. You are not a beautiful and unique snowflake.” Chuck Palahniuk
A9X-308 is offline  
post #3 of 53 Old 06-24-2020, 05:34 AM
Member
 
ifixtheinternet's Avatar
 
Join Date: Oct 2016
Posts: 189
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 105 Post(s)
Liked: 55
Quote:
Originally Posted by A9X-308 View Post
Sealed will almost always be smaller than ported and that may be needed in a given space. EQ and power as well as careful placement, using multiples etc can make up for it. Typically sealed speakers roll of in the LF at a slower rate, 12dB/oct and cabin gain in smaller rooms will bring up the low end so less EQ and power is needed.


Ported have an advantage in the fairly narrow bandwidth of the Helmholtz resonance; they are NOT more efficient than sealed, except in this narrow BW. They're larger physically, roll off at a faster rate, 24dB/oct and they really need an electrical 2nd order filter below tune to ensure that the driver does not go into over excursion with loud signal below the tune of the enclosure. Do this and you have an effective 36dB/oct roll off, so can have a narrower useful bandwidth. There's lots below 20Hz in a lot of mainly action movies.
The frequency where the different slopes meet is around 11hz. The ported wins everywhere it really matters.

I built a UM18 sealed for an 1800 cu ft space, and between AccuEQ room correction and manual EQ, I was able to get a pretty flat response down to around 10hz at 105db at the MLP.

I have to shove a lot of power into the sub at the low end though, and I suspect I'd get a lot more output from 15ish hz on up if I went ported. Do I need that? Questionable.
Do I want that? Yes.

Another consideration is bass shakers, and the boss platform which is discussed over at the hideaway theater thread.

Those can pick up where a ported drops off around 20 Hertz and provide tactile response to your seat down to like 5 hz.

You can't hear below 20 Hertz anyway so energizing the room with those frequencies doesn't make much sense to me.

If your room is much larger than 2000 cubft, or has many openings, it behooves you to do the ported sub.

Sealed subs quickly become ineffective in larger spaces.









Sent from my Pixel 3a XL using Tapatalk
ifixtheinternet is online now  
Sponsored Links
Advertisement
 
post #4 of 53 Old 06-24-2020, 06:29 AM
AVS Forum Special Member
 
johnson636's Avatar
 
Join Date: Jan 2006
Location: Somewhere in the Outer Rim
Posts: 3,540
Mentioned: 34 Post(s)
Tagged: 0 Thread(s)
Quoted: 1759 Post(s)
Liked: 1285
Quote:
Based on the WinISD outputs, why would someone choose sealed over vented?
Quote:
I understand the PE flat-pack cabinet is easy to assemble and relatively small. (Easy, Simple, and good WAF)
Quote:
The downside to vented cabinets are that they are much larger. Is the cabinet size the only reason?
You answered your own questions
tarponater likes this.

Automation: Alexa- Harmony Hub- Wemo Dimmer Switch- Wemo Smart Plug BatCave: SY Triple Black
Video Image: JVC RS500- Sony UBP-800X- Chromecast- 125" wide 16x9 white over black spandex screen
Audio: 5.2.4 Marantz SR7011- (LCR) QSC 2180 - (Surrounds) (4) BIC FH6-LCR- (Atmos) (4) Dayton Audio B652 6-1/2-Inch- (Subs)2 23ishcuft ported HS24s 14-15Hz tune - 2 Devastator Minis B&C21ds115 - 4 PA460 in ported cabs 40Hz tune- FP20000Q- 2 Sanway FP10000Q- Crown XLS1500- . To be continued...
johnson636 is offline  
post #5 of 53 Old 06-24-2020, 06:41 AM
AVS Forum Special Member
 
Join Date: Jul 2014
Posts: 5,979
Mentioned: 689 Post(s)
Tagged: 0 Thread(s)
Quoted: 3990 Post(s)
Liked: 16447
You're on the right track with your modeling and comparisons, OP.

FYI, not that it really matters, but I'd switch your units to mm for excursion and m/s for port velocity, just because that's more standard.

You can use the Max SPL graph to quickly compare max output between alignments, accounting for xmax and max power. That becomes the max headroom graph, essentially, as you can EQ the responses to anything below that, but not above. What it doesn't account for is port compression, which is very important.

To me, the absolute biggest key to ported sub design is maximizing port size, which also means maximizing port length for a given box size and tune. So decide the longest port you're comfortable with from a first port resonance perspective (for me that's about 48"), and make sure you are using all of that length to maximize your port area. Ideally, you can get max port velocity down to 20 m/s or below and then port compression will be a very minor issue and the Max SPL graph for the ported will be quite accurate around tune. Otherwise, the advantage that ported appears to have over sealed becomes partially an illusion, as port compression will not allow the ported sub to hit the SPL levels that the model shows.

Using your example of 14cf and 16.5Hz tune, using a 10" port @ 48" long, max port velocity is only 15m/s at 15.6Hz while producing 113dB natively. At that size box you can easily lower tune even further while maintaining healthy port velocity. For example, drop the port size to 8" @ 48" and tune drops down to 13.4Hz while keeping max port velocity still at only 18 m/s at 12.3Hz while producing 108dB. That's a very compelling option IMO if you value that extra extension. At that point ported is able to match sealed even down at 9Hz while having its huge advantage between 10-30Hz. Note: I am using round ports for these examples but you can just as easily do a slot port or square ports and do the same port area and make putting bends in the port much easier.

Take the Red Pill (BassEQ) BassEQ Demo Clips TR Curves
Video: Sony 85" X900F @ 80" eyes-to-screen (49.4° viewing angle)
Audio: Denon AVR-X4400H 7.2.4 Atmos
Mains: Fusion-15 LR, Fusion-8 Center, Ported Volt-10 Surrounds, Custom 45°/45° Double-Angled Ported Volt-6 Atmos
Subs: The Two Towers (HT18 32cf 11.5Hz x 2), UM18 4cf x 2, Crowson MAs x 4
aron7awol is offline  
post #6 of 53 Old 06-24-2020, 06:49 AM
Senior Member
 
tarponater's Avatar
 
Join Date: Jan 2018
Location: DUUUUUUUUUVAL
Posts: 483
Mentioned: 46 Post(s)
Tagged: 0 Thread(s)
Quoted: 235 Post(s)
Liked: 817
Something else to consider when reading another persons impressions about a particular driver. You have no idea what that person has listened to. If they are used to a 10" Polk subwoofer, a simple 15" ported DIY will blow their mind. If they are used to HS24s, they will be thoroughly unimpressed with a sealed 18". (in general) My personal opinion, if you're looking for over the top output, like most of this community, go as large of a driver in as large a cabinet that you can fit in your space. Have fun!

JVC RS-540, Sony UBP-X800, Onkyo TX-RZ730 (7.2.4), Onkyo M-5010, Elite Screens 100" 16:9 (Spandex AT DIY)
DIYSG 1099 LCR, Polk TSX-150C (DIY) Atmos, Yamaha NS333 Surround & Surround Back
Triple HS-24 mkiii sealed, Dual SAN 214.5 Devastators, Dual Crowson actuators, NU12000, NX6000, XLS-2502, MINIDSP 2X4
tarponater is offline  
post #7 of 53 Old 06-24-2020, 06:54 AM
AVS Forum Special Member
 
johnson636's Avatar
 
Join Date: Jan 2006
Location: Somewhere in the Outer Rim
Posts: 3,540
Mentioned: 34 Post(s)
Tagged: 0 Thread(s)
Quoted: 1759 Post(s)
Liked: 1285
I 100% agree with the above post

Automation: Alexa- Harmony Hub- Wemo Dimmer Switch- Wemo Smart Plug BatCave: SY Triple Black
Video Image: JVC RS500- Sony UBP-800X- Chromecast- 125" wide 16x9 white over black spandex screen
Audio: 5.2.4 Marantz SR7011- (LCR) QSC 2180 - (Surrounds) (4) BIC FH6-LCR- (Atmos) (4) Dayton Audio B652 6-1/2-Inch- (Subs)2 23ishcuft ported HS24s 14-15Hz tune - 2 Devastator Minis B&C21ds115 - 4 PA460 in ported cabs 40Hz tune- FP20000Q- 2 Sanway FP10000Q- Crown XLS1500- . To be continued...
johnson636 is offline  
post #8 of 53 Old 06-24-2020, 06:56 AM
AVS Forum Special Member
 
Join Date: Jul 2014
Posts: 5,979
Mentioned: 689 Post(s)
Tagged: 0 Thread(s)
Quoted: 3990 Post(s)
Liked: 16447
Yeah, the 4cf sealed UM18 flatpacks (and other sealed subs) are a great option in smaller rooms with good gain, where the native in-room response ends up pretty flat or rising without much low-end boost. In other rooms, like mine, I'd need 8 or 16 of them to get any kind of good output down at 10Hz. The two flatpacks I added to my system added next to nothing because my ported monsters have way more output down low and I need every bit of it in my room. The flatpack subs are essentially speaker stands that look like subwoofers.
tarponater likes this.

Take the Red Pill (BassEQ) BassEQ Demo Clips TR Curves
Video: Sony 85" X900F @ 80" eyes-to-screen (49.4° viewing angle)
Audio: Denon AVR-X4400H 7.2.4 Atmos
Mains: Fusion-15 LR, Fusion-8 Center, Ported Volt-10 Surrounds, Custom 45°/45° Double-Angled Ported Volt-6 Atmos
Subs: The Two Towers (HT18 32cf 11.5Hz x 2), UM18 4cf x 2, Crowson MAs x 4
aron7awol is offline  
post #9 of 53 Old 06-24-2020, 08:41 AM
AVS Forum Special Member
 
Join Date: Sep 2016
Posts: 1,457
Mentioned: 25 Post(s)
Tagged: 0 Thread(s)
Quoted: 571 Post(s)
Liked: 474
Quote:
Originally Posted by tarponater View Post
Something else to consider when reading another persons impressions about a particular driver. You have no idea what that person has listened to. If they are used to a 10" Polk subwoofer, a simple 15" ported DIY will blow their mind. If they are used to HS24s, they will be thoroughly unimpressed with a sealed 18". (in general) My personal opinion, if you're looking for over the top output, like most of this community, go as large of a driver in as large a cabinet that you can fit in your space. Have fun!
What I find when others give listening impressions is they normally describe their room modes. You'll hear terms like boom and quick and what ever else that is more so do with their room than the sub.


I understand that a majority of the DIY community won't be measuring their room or applying DSP (or both) to their set up, but most times an opinion on a sub is characterized by their lack of understanding with how it interacts with their given space.


OP - as others have said you are on the right track and also have the right assumptions.


I'd also mention that sealed is the safest way to build a sub and is the best for a person who is less interested in the details. Take the UM18 for example, it'll be really hard to break it on a standard 15amp circuit in a 4.0 cu/ft sealed box. Its response is also incredible in that alignment too.
Trimlock is offline  
post #10 of 53 Old 06-24-2020, 08:52 AM
AVS Forum Special Member
 
Join Date: Jul 2014
Posts: 5,979
Mentioned: 689 Post(s)
Tagged: 0 Thread(s)
Quoted: 3990 Post(s)
Liked: 16447
Quote:
Originally Posted by Trimlock View Post
I'd also mention that sealed is the safest way to build a sub and is the best for a person who is less interested in the details. Take the UM18 for example, it'll be really hard to break it on a standard 15amp circuit in a 4.0 cu/ft sealed box. Its response is also incredible in that alignment too.
Actually, I'd argue that sealed often requires more paying attention to the details rather than simply running room correction, because it may require low-end boost to properly utilize the sub's capabilities, which room correction isn't going to apply. And once we start adding low-end boost, we need to really know what we're doing to make sure we aren't using up too much headroom for a user's particular listening levels.

Sure, ported needs a proper HPF, but that's really simple to add, and then it's pretty much just as safe and hard to break as a sealed UM18. Then someone just running room correction has a much better change of getting a good EQed response with the extension the sub is capable of. And the additional headroom of the ported serves as additional protection.

The 4cf sealed response is "incredible"? What's incredible about it? It's a standard sealed response, it's pretty much the bottom of the barrel response. Sure, it can work out well in the right room, but there's nothing incredible about it IMO.

Take the Red Pill (BassEQ) BassEQ Demo Clips TR Curves
Video: Sony 85" X900F @ 80" eyes-to-screen (49.4° viewing angle)
Audio: Denon AVR-X4400H 7.2.4 Atmos
Mains: Fusion-15 LR, Fusion-8 Center, Ported Volt-10 Surrounds, Custom 45°/45° Double-Angled Ported Volt-6 Atmos
Subs: The Two Towers (HT18 32cf 11.5Hz x 2), UM18 4cf x 2, Crowson MAs x 4

Last edited by aron7awol; 06-24-2020 at 09:33 AM.
aron7awol is offline  
post #11 of 53 Old 06-24-2020, 11:34 AM
AVS Forum Special Member
 
Join Date: Sep 2016
Posts: 1,457
Mentioned: 25 Post(s)
Tagged: 0 Thread(s)
Quoted: 571 Post(s)
Liked: 474
UM18-22, Sealed versus Vented, why?

Quote:
Originally Posted by aron7awol View Post
Actually, I'd argue that sealed often requires more paying attention to the details rather than simply running room correction, because it may require low-end boost to properly utilize the sub's capabilities, which room correction isn't going to apply. And once we start adding low-end boost, we need to really know what we're doing to make sure we aren't using up too much headroom for a user's particular listening levels.

Sure, ported needs a proper HPF, but that's really simple to add, and then it's pretty much just as safe and hard to break as a sealed UM18. Then someone just running room correction has a much better change of getting a good EQed response with the extension the sub is capable of. And the additional headroom of the ported serves as additional protection.

The 4cf sealed response is "incredible"? What's incredible about it? It's a standard sealed response, it's pretty much the bottom of the barrel response. Sure, it can work out well in the right room, but there's nothing incredible about it IMO.

Show me another sub that is $300 that presents a flat response down to the 30’s with the same sensitivity to ULF in a similar sized box.

We can nitpick everything down to a specific and say something is more dangerous. The fact is, by itself, on a 15amp circuit and a typical amp you won’t destroy a sealed UM18. If you start including boost, the most dangerous thing to do would be to overly boost mid bass frequencies on the UM as that’ll blow the voice before excursion ever would.


Sent from my iPhone using Tapatalk

Last edited by Trimlock; 06-24-2020 at 11:42 AM.
Trimlock is offline  
post #12 of 53 Old 06-24-2020, 12:16 PM
AVS Forum Special Member
 
Join Date: Jul 2014
Posts: 5,979
Mentioned: 689 Post(s)
Tagged: 0 Thread(s)
Quoted: 3990 Post(s)
Liked: 16447
Quote:
Originally Posted by Trimlock View Post
Show me another sub that is $300 that presents a flat response down to the 30’s with the same sensitivity to ULF in a similar sized box.
We aren't talking about the UM18 vs another driver. I love the UM18 for the money in any alignment. We're talking about the UM18 sealed vs ported. You said the response sealed was incredible, I questioned why you would say that, it's a pretty standard sealed response, nothing special. If you are just talking about the UM18 in general, then I think we both agree it's great for the money.

Quote:
Originally Posted by Trimlock View Post
We can nitpick everything down to a specific and say something is more dangerous. The fact is, by itself, on a 15amp circuit and a typical amp you won’t destroy a sealed UM18. If you start including boost, the most dangerous thing to do would be to overly boost mid bass frequencies on the UM as that’ll blow the voice before excursion ever would.
Right, and the same exact points stand with a ported UM18, as long as it has a proper HPF (which I consider simple enough for anyone building a sub), but with even more headroom/safety factor where it has an advantage over sealed. You said you think sealed is a simpler option and gave some reasons why. I responded that I actually think ported is simpler and gave the reasons why.

I think it's an often overlooked drawback of trying to use sealed subs in the simplest room correction only case, it's very dependent on the in-room native response shape being flat enough that room correction will do its thing with it. And then if not, even if the user is willing and able to give it some low-end boost to flatten it out before running room correction, there are some important headroom considerations to make there, it becomes more of an advanced exercise that requires balancing extension, capabilities, listening level. As opposed to a ported scenario where the native in-room response is far more likely to be flat or rising, and simply running room correction more often results in a nice flat response with full extension. It's not necessarily a deal maker or breaker, but like I said, I think it's an often overlooked part of running room correction only with sealed subs.
asarose247 likes this.

Take the Red Pill (BassEQ) BassEQ Demo Clips TR Curves
Video: Sony 85" X900F @ 80" eyes-to-screen (49.4° viewing angle)
Audio: Denon AVR-X4400H 7.2.4 Atmos
Mains: Fusion-15 LR, Fusion-8 Center, Ported Volt-10 Surrounds, Custom 45°/45° Double-Angled Ported Volt-6 Atmos
Subs: The Two Towers (HT18 32cf 11.5Hz x 2), UM18 4cf x 2, Crowson MAs x 4
aron7awol is offline  
post #13 of 53 Old 06-24-2020, 01:09 PM
AVS Forum Special Member
 
Join Date: Sep 2016
Posts: 1,457
Mentioned: 25 Post(s)
Tagged: 0 Thread(s)
Quoted: 571 Post(s)
Liked: 474
Quote:
Originally Posted by aron7awol View Post
You said the response sealed was incredible, I questioned why you would say that, it's a pretty standard sealed response, nothing special.
This is where I disagree. For sealed that is.

It’s special because there aren’t a whole mass of sub drivers available that show a good native response in a sealed box, normally they have a huge arc. In the case of the UM, you don’t start the drop off till the mid 30’s, in a box where the QTC isn’t .707 either. Technically the driver does doesn’t need the technical .707 to function properly but that’s another discussion.

Either way, my praise for it is that it doesn’t show typical early sealed roll off, still maintains great great ULF sensitivity and has a balanced box size. I also do not think this typical of sealed sub drivers either, but I could be wrong!


Sent from my iPhone using Tapatalk
Trimlock is offline  
post #14 of 53 Old 06-24-2020, 02:11 PM
AVS Forum Special Member
 
A9X-308's Avatar
 
Join Date: Mar 2008
Location: Australia
Posts: 8,738
Mentioned: 35 Post(s)
Tagged: 0 Thread(s)
Quoted: 2035 Post(s)
Liked: 1751
Snipped in many places.
Quote:
Originally Posted by ifixtheinternet View Post
The ported wins everywhere it really matters.
No, as I said, it depends on what you're trying to accomplish and the limitations such as enclosure size etc you may be able to live with.
My comments you quoted, were general in mature and not specific to the UM18


Quote:
Originally Posted by ifixtheinternet View Post
Another consideration is bass shakers
Those can pick up where a ported drops off around 20 Hertz and provide tactile response to your seat down to like 5 hz.
See next comment.

Quote:
Originally Posted by ifixtheinternet View Post
You can't hear below 20 Hertz anyway so energizing the room with those frequencies doesn't make much sense to me.
You've obviously never felt it; it's not the same as shakers. I have Crowsons.

Quote:
Originally Posted by ifixtheinternet View Post
If your room is much larger than 2000 cubft, or has many openings, it behooves you to do the ported sub.
My current room is 1830cf and my four sealed FTW21s go deep and loud, and the room has to large non sealable openings.

Quote:
Originally Posted by ifixtheinternet View Post
Sealed subs quickly become ineffective in larger spaces.
Meh. Try nearfield.

“You are not special. You are not a beautiful and unique snowflake.” Chuck Palahniuk
A9X-308 is offline  
post #15 of 53 Old 06-24-2020, 02:36 PM
AVS Forum Special Member
 
Join Date: Jul 2014
Posts: 5,979
Mentioned: 689 Post(s)
Tagged: 0 Thread(s)
Quoted: 3990 Post(s)
Liked: 16447
Quote:
Originally Posted by Trimlock View Post
Show me another sub that is $300 that presents a flat response down to the 30’s with the same sensitivity to ULF in a similar sized box.
Quote:
Originally Posted by Trimlock View Post
It’s special because there aren’t a whole mass of sub drivers available that show a good native response in a sealed box, normally they have a huge arc. In the case of the UM, you don’t start the drop off till the mid 30’s, in a box where the QTC isn’t .707 either. Technically the driver does doesn’t need the technical .707 to function properly but that’s another discussion.

Either way, my praise for it is that it doesn’t show typical early sealed roll off, still maintains great great ULF sensitivity and has a balanced box size. I also do not think this typical of sealed sub drivers either, but I could be wrong!
Well, there aren't many $300 drivers in general, but here are some in that range off the top of my head that work well in 4cf sealed or smaller:
UM18 $325
Fi HT-1 $299
SI SQL-15 $320
SI SQL-12 $290

In any case, to be clear, I'm a HUGE fan of the UM18 for the money, in any alignment, including sealed. I recommend it first to everyone I design a sub for, for that reason. I just don't see anything special or magical about its sealed response. It's a pretty typical low-sensitivity high-excursion driver sealed response. Are you comparing it to high-sensitivity PA drivers? Well, that's a different animal. The Fi HT-1 is probably its closest competition on the market, with it being $299 and being an 18, and it has a very similar response.

Take the Red Pill (BassEQ) BassEQ Demo Clips TR Curves
Video: Sony 85" X900F @ 80" eyes-to-screen (49.4° viewing angle)
Audio: Denon AVR-X4400H 7.2.4 Atmos
Mains: Fusion-15 LR, Fusion-8 Center, Ported Volt-10 Surrounds, Custom 45°/45° Double-Angled Ported Volt-6 Atmos
Subs: The Two Towers (HT18 32cf 11.5Hz x 2), UM18 4cf x 2, Crowson MAs x 4
aron7awol is offline  
post #16 of 53 Old 06-24-2020, 03:02 PM
Member
 
ifixtheinternet's Avatar
 
Join Date: Oct 2016
Posts: 189
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 105 Post(s)
Liked: 55
Quote:
Originally Posted by A9X-308 View Post
Snipped in many places.No, as I said, it depends on what you're trying to accomplish and the limitations such as enclosure size etc you may be able to live with.
My comments you quoted, were general in mature and not specific to the UM18


See next comment.

You've obviously never felt it; it's not the same as shakers. I have Crowsons.

My current room is 1830cf and my four sealed FTW21s go deep and loud, and the room has to large non sealable openings.

Meh. Try nearfield.
Oh you sure got me good!

Ill be more specific.

The ported box with a um18 will win in SPL output at every *frequency* that really matters, over the sealed.
The modeled response demonstrates that.
They are equal at about 11 Hertz.
Above that the ported has more output.

I understand there are other considerations, I was strictly talking frequency response.

I said one option is adding tactile to supplement ported subs, and it is. If that's not your preference that's fine. Many sealed subs or running nearfield is not an option for many, including myself.

It doesn't make sense to me to load a room with many sealed subs and immense amounts of power when you can replace that with a single ported sub and some tactile response.

Maybe it makes sense for you but not for me, and not for most other people.

The OP is asking about a single sub, and in a larger room, sealed subs placed anywhere EXCEPT nearfield is going to yield completely inadequate performance.

Sent from my Pixel 3a XL using Tapatalk
ifixtheinternet is online now  
post #17 of 53 Old 06-24-2020, 03:17 PM
Member
 
Join Date: Jan 2020
Posts: 106
Mentioned: 2 Post(s)
Tagged: 0 Thread(s)
Quoted: 69 Post(s)
Liked: 27
Quote:
Originally Posted by aron7awol View Post
Fi HT-1 $299
the HT-1 does have more output than the UM18 above 35ish hertz but does drop off earlier(still ends up with the same low end output)
aron7awol likes this.
bogaboga is offline  
post #18 of 53 Old 06-24-2020, 04:22 PM
AVS Forum Special Member
 
Join Date: Jul 2014
Posts: 5,979
Mentioned: 689 Post(s)
Tagged: 0 Thread(s)
Quoted: 3990 Post(s)
Liked: 16447
Quote:
Originally Posted by bogaboga View Post
the HT-1 does have more output than the UM18 above 35ish hertz but does drop off earlier(still ends up with the same low end output)
Thanks, that graph proves my point. There's nothing special about the response, they are almost identical, the HT-1 just looks to be about 1dB more sensitive up top.

Take the Red Pill (BassEQ) BassEQ Demo Clips TR Curves
Video: Sony 85" X900F @ 80" eyes-to-screen (49.4° viewing angle)
Audio: Denon AVR-X4400H 7.2.4 Atmos
Mains: Fusion-15 LR, Fusion-8 Center, Ported Volt-10 Surrounds, Custom 45°/45° Double-Angled Ported Volt-6 Atmos
Subs: The Two Towers (HT18 32cf 11.5Hz x 2), UM18 4cf x 2, Crowson MAs x 4
aron7awol is offline  
post #19 of 53 Old 06-24-2020, 04:29 PM
AVS Forum Special Member
 
Join Date: Sep 2016
Posts: 1,457
Mentioned: 25 Post(s)
Tagged: 0 Thread(s)
Quoted: 571 Post(s)
Liked: 474
Quote:
Originally Posted by aron7awol View Post
Well, there aren't many $300 drivers in general, but here are some in that range off the top of my head that work well in 4cf sealed or smaller:
UM18 $325
Fi HT-1 $299
SI SQL-15 $320
SI SQL-12 $290

In any case, to be clear, I'm a HUGE fan of the UM18 for the money, in any alignment, including sealed. I recommend it first to everyone I design a sub for, for that reason. I just don't see anything special or magical about its sealed response. It's a pretty typical low-sensitivity high-excursion driver sealed response. Are you comparing it to high-sensitivity PA drivers? Well, that's a different animal. The Fi HT-1 is probably its closest competition on the market, with it being $299 and being an 18, and it has a very similar response.
The SQL-15 doesn't sim as well, but this is kind of what I'm talking about drivers in sealed alignment. It drops off early in the 80's and has a shallow slope to eventually catch up to the 18's. There are Klippel floating around though that pretty much confirms the T/S they posted. To be clear, I'm really excited about this driver, very excited. It has the headroom to boost down low and really kickass.

I admit I did forget about the Fi, but the Fi rocks a relatively weak motor with no shorting rings, still if it does measure similar to the sims then it does indeed beat the UM18. So theres 2 drivers with similar responses in smaller boxes, unless I am forgetting anymore. To me that is a pretty awesome response. Remember you are challenging my opinion that the UM18 has an 'incredible' response in a sealed alignment, I never said it was unique or better than a ported alignment. We have come to find out that Fi has a similar looking driver, and if I remember correctly that was their intent. It also bothers me that Fi Doesn't post Le either and their CMS numbers are commonly different then whats found ….

I did consider PA drivers in sealed boxes but there are only two that I know of that has a decent response in sealed boxes and they aren't exactly priced in the ranges we are discussing so no, I'm not considering those.

I was going to buy the SQL-15, it is in my future but I am deploying … yet again so that's a plan I have to hold off on. I was hoping to measure it in a fairly massive sealed box to see how it would handle north of 1000w and hit xmax. This would eventually go into my Wrangler as I don't need to upgrade from my 21's at home.

Also don't forget, the Fi has the SSD's (great driver), PSI has … something … I'll remember it I'm sure and there is of course Sundown. Now I never said specifically 18" but I wanted it compared to a driver that is $300 (or similar) in a similar sealed box. To me it is very nice response.
Trimlock is offline  
post #20 of 53 Old 06-24-2020, 06:51 PM - Thread Starter
Member
 
-Pjackso's Avatar
 
Join Date: Dec 2003
Posts: 169
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 5 Post(s)
Liked: 10
Wow,

What an awesome community! Lots of great insight and experiences.
So, just to clarify - yes, this is for home theater purposes - in a open large (800-1000) sq ft room with typical 8' ceilings.

Given the discussion, each design is appropriate for difference scenarios. ( correct me if I'm wrong )

Sealed subs are more appropriate when:
1) Smaller boxes are required, 2) Used in smaller rooms, 3) Sealed cabinets helps to limit cone over-excursion, 4) Sealed unfortunately constricts the (SPL) output of lower frequencies.
***The constricted lower frequencies can be compensated partially by amplifier boost, or by having (more) speakers.

Ported subs are more appropriate when:
1) Larger boxes are acceptable, 2) Used in larger rooms, 3) More output at lower frequencies, 4) Ported cabinets must be managed to avoid cone over-excursion.
***Cone-excursion can be managed via HPF or reducing amplifier size (less wattage).




Different people have different goals regarding "Sub-woofers".
I consider the entire purpose of a sub-woofer is to maximize the production of lower frequencies (below 35-40 hz) at sufficient SPL levels with a flat response.

If the goal is 35-40hz and up - then (in my opinion) any box-store subwoofer is the easy 80% solution.
So when I see the UM18 in a 4.0 cu ft sealed box, with a F3 roll-off of 30 hz - I'd consider that mostly equivalent to store-bought sub-woofer performance.
To clarify - If you're happy with sealed subs - then more power to you.
Maybe there's more to it. I just don't get it.


Looks like I'll be trying a ported design.
Ok - more questions......


-Can you please discuss more about 'port-compression'?
I have the understanding that the port does 2 things. 1) It's TUNED to a certain frequency, and 2) it's for air intake/exhaust due to the driver displacement.
The port air-velocity should try to be minimized - or you'll hear 'chugging'. (110 ft/s or less?) You can reduce air-velocity with more vents - or larger diameter vents.
I've never seen 'port-compression' referenced.



-I could also use some insight regarding 'room-gain'.
My room is large and open, ...although the theater (big screen) is in a corner of the room - not the whole thing.
I have (0) knowledge on this, but seen it discussed a lot - and it seems important.
How do I understand this, and how does it impact sub-woofer designs?
Please use small words. : )


-My 14 cu ft ported design has an inherently flat response down to 16 hz (+/- 3db).
I am mostly new to DSP's. Is there any point in a DSP?
I understand them as 'digital equalizers' to custom set for unique rooms interactions. Yes?
Good/bad/unnecessary?


Thanks.

-Nothing relevant to add.

Last edited by -Pjackso; 06-24-2020 at 06:58 PM.
-Pjackso is offline  
post #21 of 53 Old 06-24-2020, 08:25 PM
AVS Forum Special Member
 
A9X-308's Avatar
 
Join Date: Mar 2008
Location: Australia
Posts: 8,738
Mentioned: 35 Post(s)
Tagged: 0 Thread(s)
Quoted: 2035 Post(s)
Liked: 1751
Quote:
Originally Posted by -Pjackso View Post
-Can you please discuss more about 'port-compression'?
I have the understanding that the port does 2 things. 1) It's TUNED to a certain frequency, and 2) it's for air intake/exhaust due to the driver displacement.
The port air-velocity should try to be minimized - or you'll hear 'chugging'. (110 ft/s or less?) You can reduce air-velocity with more vents - or larger diameter vents.
I've never seen 'port-compression' referenced.
Max port air speed will be at tuning, and the port needs to pass that without becoming to resistive, so it needs to be as large as possible to keep the PAS as low as possible. However, the large CSA of a port the longer it will need to be, so some manufacturers use the shortest port possible. When it tries to pass the max volume of air, the CSA will be too low and it will behave like a dynamic filter at port tune, reducing output at the highest levels, but not at lower levels so it still measures well at low levels. Manufacturers won't talk about it because it's their dirty little secret. I try to keep PAS below 15m/s.



Chuffing is more what happens when the air is in a fairly high impedance zone, in the port, and it comes to the open air, their is shear in the flow and this sound can become audible. Where that is and how bad depends upon the tuning and design of the port and box. This why many ports have flared ends, and note that because the port is bidirectional in flow, the intake (inside the enclosure) is also best flared.

“You are not special. You are not a beautiful and unique snowflake.” Chuck Palahniuk
A9X-308 is offline  
post #22 of 53 Old 06-24-2020, 09:17 PM
AVS Forum Addicted Member
 
BassThatHz's Avatar
 
Join Date: Apr 2008
Location: Northern Okan range (NW Cascades region)
Posts: 11,415
Mentioned: 258 Post(s)
Tagged: 0 Thread(s)
Quoted: 4058 Post(s)
Liked: 4579
Ported and Horned works great but only for outdoors or in large rooms, and/or for people who don't mind being [email protected]

I've heard quad 16hz ported Full Marties.
I've also heard my own system (which is mostly all-sealed.)
My system wins easily...

Here's my stance on the topic, if I'm gonna drop >$20k on 32 subwoofers, I want ALL the frequencies, not just some of them! PERIOD!
I can easily hear 12hz, and I can feel 5hz easily (with a concrete floor and no butt shakers.)

You couldn't pay me to port all my subs (ok ok... maybe for $100k I'd re-consider it "temporarily", before reverting right back to an all-sealed design. )

The thing is: Ported doesn't scale well once go past about ~8 subs.
Who wants to deploy 32 ported subs and spend 5 figures doing that, taking up a barn of space, and still be [email protected]? (Answer: Nobody! )
Ported and Horned only works well for small quantities of woofers, or outdoors, or in a 200'x200'x50' Cinema / Barn (where 5hz is gonna be unpossible via conventional-methods.)

sealed CAN work in small spaces; and IB/sealed can also work if you want the least-rolloff and no port noise at ANY db!

It's a balance of budget, space and priorities.
Different strokes for different folks: 2000HP Lambo vs Armored Royce Limo.
One is just really-loud, the other gets you there while you eat some breakfast and without any holes...
BassThatHz is offline  
post #23 of 53 Old 06-25-2020, 07:41 AM
AVS Forum Special Member
 
Join Date: Sep 2016
Posts: 1,457
Mentioned: 25 Post(s)
Tagged: 0 Thread(s)
Quoted: 571 Post(s)
Liked: 474
Quote:
Originally Posted by -Pjackso View Post
-Can you please discuss more about 'port-compression'?
I have the understanding that the port does 2 things. 1) It's TUNED to a certain frequency, and 2) it's for air intake/exhaust due to the driver displacement.
The port air-velocity should try to be minimized - or you'll hear 'chugging'. (110 ft/s or less?) You can reduce air-velocity with more vents - or larger diameter vents.
I've never seen 'port-compression' referenced.



-I could also use some insight regarding 'room-gain'.
My room is large and open, ...although the theater (big screen) is in a corner of the room - not the whole thing.
I have (0) knowledge on this, but seen it discussed a lot - and it seems important.
How do I understand this, and how does it impact sub-woofer designs?
Please use small words. : )


-My 14 cu ft ported design has an inherently flat response down to 16 hz (+/- 3db).
I am mostly new to DSP's. Is there any point in a DSP?
I understand them as 'digital equalizers' to custom set for unique rooms interactions. Yes?
Good/bad/unnecessary?


Thanks.
1. The port is not an exhaust, the tuning uses an air slug to achieve tuning. Essentially moving the air back and forth is what achieves the output. If this is restricted than the output is lowered requiring more power. If your port is too small it won't match the sims in WinISD as it doesn't predict port compression. What you want is to keep the port msec down below a desired range, if its high you'll hear it.

Builders can also take advantage of smaller ports by building based off of planned power usage. Take for example your build can handle 2500watts but your compression is obscene, how ever at 800watts (your planned amps RMS rating) you'll be well below port compression. That doesn't really leave you with the ability to upgrade but then again you'll have to ask yourself if you do plan to eventually upgrade.

2. & 3. Both of these play into each other, where you have room gain you also have dips and spikes. DSP is necessary to tame these or you'll have some wicked booms.
Trimlock is offline  
post #24 of 53 Old 06-25-2020, 08:48 AM
Member
 
Quetzalcoalt's Avatar
 
Join Date: Dec 2017
Location: Bulgaria
Posts: 174
Mentioned: 2 Post(s)
Tagged: 0 Thread(s)
Quoted: 131 Post(s)
Liked: 181
Wow replied yesterday to the wrong thread
So here is my point of view.

With the UM18, the issue is that it needs a BIG box. The box needs to be soo big you can fit 2 sealed UM18 in the same space. I don't think a single 18 in a vented box will be better at SPL than 2x18s even at the tuning frequencies.
Keep in mind that sealed really benefits from room gain.
Sealed is easy to build, takes a small space (or takes the same space with 2x the drivers -> 2x more surface area).
No need to worry about port velocity and keeping the port resonance at check.
With this new invention called the BOSS and all of its variations you don't even need anything under 18hz, unless you want to "feel" the bass while you hear your hours rattle.
Another plus is the group delay, or the so called how fast a sub is. Everyone says sealed is always faster than vented. I haven't heard subs at this caliber in a vented box so i can't speak for myself. The only thing i can tell you is that when i watch a movie i can't remove my smile from my face.

I just finished building 2xUM18 in sealed boxes. I didn't need to boost the low end i had to reduce massive peaks (14db at 30hz), at the end i'm flat down to 18hz. My subs are placed at the absolute worst place in the room and the room is super bad (it's 50% windows from floor to ceiling). I've done 110db at 20hz at the current tuning. I still need to see how much SPL i can do. Looking at the cone movement i think i can squeeze another 3db of each driver. Can't find time to make some videos =/

If i could place them in the corners it would be even louder with less cone movement. But maybe, there is a very very small chance i can fit 1 or 2 more subs somewhere in the room in the future.

EDIT: so my response is a day late. I want to add something. When you model a sub in winISD for example, the response you see is in open space (technically an anechoic chamber), it will greatly differ when you place the sub in YOUR room. Speakers behave substantially different in a room, based on it's size, what materials were used to build the room, and the interior, furniture, carpets, ect. Also the elevation of the house changes the frequency response, because sound travels at different speeds depending on how dense the air is. That's why you can change those variable if you are gonna build speakers for a hours placed at 3000m above sea level.
ultrabubu and Bnaan like this.

Last edited by Quetzalcoalt; 06-25-2020 at 08:59 AM.
Quetzalcoalt is offline  
post #25 of 53 Old 06-25-2020, 09:08 AM
Member
 
ifixtheinternet's Avatar
 
Join Date: Oct 2016
Posts: 189
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 105 Post(s)
Liked: 55
Quote:
Originally Posted by Quetzalcoalt View Post
Wow replied yesterday to the wrong thread

So here is my point of view.



With the UM18, the issue is that it needs a BIG box. The box needs to be soo big you can fit 2 sealed UM18 in the same space. I don't think a single 18 in a vented box will be better at SPL than 2x18s even at the tuning frequencies.

Keep in mind that sealed really benefits from room gain.
The modeled output of the ported enclosure shows a nearly 10db gain at 20hz.

By adding a 2nd equal sub, you can expect only 3db gain.
So according to that you would need at least between 3-4 sealed UM18 to equal the single ported around the port tune.

Of course you can boost the low end in the sealed boxes, but I don't think you could boost enough even with two subs to come close to a single ported enclosure around tuning.

The advantage there is placing the subs in different spots will even out the peaks and dips though.

Room gain will affect ported subs equally as sealed, so you will get an even bigger boost to the low end in a smaller room.
However after building a sealed UM18 I was surprised how little room gain I got in a 1800ish cu ft room.




Sent from my Pixel 3a XL using Tapatalk
bogaboga likes this.
ifixtheinternet is online now  
post #26 of 53 Old 06-25-2020, 09:56 AM
AVS Forum Special Member
 
Join Date: Sep 2016
Posts: 1,457
Mentioned: 25 Post(s)
Tagged: 0 Thread(s)
Quoted: 571 Post(s)
Liked: 474
Quote:
Originally Posted by ifixtheinternet View Post
The modeled output of the ported enclosure shows a nearly 10db gain at 20hz.

By adding a 2nd equal sub, you can expect only 3db gain.
So according to that you would need at least between 3-4 sealed UM18 to equal the single ported around the port tune.

Of course you can boost the low end in the sealed boxes, but I don't think you could boost enough even with two subs to come close to a single ported enclosure around tuning.

The advantage there is placing the subs in different spots will even out the peaks and dips though.

Room gain will affect ported subs equally as sealed, so you will get an even bigger boost to the low end in a smaller room.
However after building a sealed UM18 I was surprised how little room gain I got in a 1800ish cu ft room.




Sent from my Pixel 3a XL using Tapatalk
Did you measure the entire room or only the MLP? Realistically you should be seeing a pretty massive amount of room gain if you're in a 12x14 room, or is it an open room?

I still think the bigger advantage of sealed subs is the slope, ported starts to rise in distortion fast post tuning and unless you are boosting the low end on a sealed you won't be seeing too high distortion there.
Trimlock is offline  
post #27 of 53 Old 06-25-2020, 10:06 AM
Member
 
ifixtheinternet's Avatar
 
Join Date: Oct 2016
Posts: 189
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 105 Post(s)
Liked: 55
Quote:
Originally Posted by Trimlock View Post
Did you measure the entire room or only the MLP? Realistically you should be seeing a pretty massive amount of room gain if you're in a 12x14 room, or is it an open room?



I still think the bigger advantage of sealed subs is the slope, ported starts to rise in distortion fast post tuning and unless you are boosting the low end on a sealed you won't be seeing too high distortion there.
Yes, I measured several different positions in the living room, and everything below 40 Hertz remained pretty much unchanged, only 1-2db difference. The uncorrected frequency response was actually very disappointing.
Basically looks like a pyramid peaking at 40 Hertz.

The biggest difference moving it around was actually in the mid bass region, from around 70-100hz.

I found this was critical because the um18 is not a good mid bass producer. in fact there was such a huge drop off in the mid bass in certain positions, my receiver refused to apply any room correction until I moved it into the corner facing the wall, which boosted the mid-bass by about 6db.

I have a large 8 by 10 foot opening on the left into the dining room, and a hallway opening on the front right side. I think it's mainly the openings that kill the room gain for me.

Sent from my Pixel 3a XL using Tapatalk

Last edited by ifixtheinternet; 06-25-2020 at 10:10 AM.
ifixtheinternet is online now  
post #28 of 53 Old 06-25-2020, 10:20 AM
AVS Forum Special Member
 
Join Date: Sep 2016
Posts: 1,457
Mentioned: 25 Post(s)
Tagged: 0 Thread(s)
Quoted: 571 Post(s)
Liked: 474
Quote:
Originally Posted by ifixtheinternet View Post
Yes, I measured several different positions in the living room, and everything below 40 Hertz remained pretty much unchanged, only 1-2db difference. The uncorrected frequency response was actually very disappointing.
Basically looks like a pyramid peaking at 40 Hertz.

The biggest difference moving it around was actually in the mid bass region, from around 70-100hz.

I found this was critical because the um18 is not a good mid bass producer. in fact there was such a huge drop off in the mid bass in certain positions, my receiver refused to apply any room correction until I moved it into the corner facing the wall, which boosted the mid-bass by about 6db.

I have a large 8 by 10 foot opening on the left into the dining room, and a hallway opening on the front right side. I think it's mainly the openings that kill the room gain for me.

Sent from my Pixel 3a XL using Tapatalk
Interesting the room correction had safeguards, I know of an individual that ruined his SVS sub because room correction put his sub at 10db hot in the midbass. Pretty sure he was using a Yamaha.

I agree, I think your opening is ruining your room gain, my room is also open and I see very few and small peaks with my subs, which are 2x NSW6021's tuned to 17hz.
ifixtheinternet likes this.
Trimlock is offline  
post #29 of 53 Old 06-25-2020, 11:50 AM
AVS Forum Special Member
 
zeus33's Avatar
 
Join Date: Dec 2012
Posts: 4,438
Mentioned: 18 Post(s)
Tagged: 0 Thread(s)
Quoted: 2004 Post(s)
Liked: 2289
Quote:
Originally Posted by Quetzalcoalt View Post
Everyone says sealed is always faster than vented.

No, "everyone" doesn't say that. Only the misinformed that continue repeating an old myth. That myth was based on old poorly designed subs with weak motor strength that didn't control the cone properly and sounded boomy/sloppy. A properly built/designed ported sub will sound just as "fast" as a sealed one.
zeus33 is online now  
post #30 of 53 Old 06-25-2020, 01:04 PM
AVS Forum Special Member
 
Join Date: Jul 2014
Posts: 5,979
Mentioned: 689 Post(s)
Tagged: 0 Thread(s)
Quoted: 3990 Post(s)
Liked: 16447
Oh boy. This thread is devolving, like most sealed vs ported threads do. Why is it that every time this sort of discussion happens, everyone who has sealed subs has to repeat the same old myths, misconceptions, and pseudo-science to justify that they have sealed subs in their systems and they work well and they are happy with them?

For the record, I have both alignments actively in my system, and I have no bias either way. They are what they are, with their strengths and weaknesses.

Quote:
Originally Posted by Quetzalcoalt View Post
With the UM18, the issue is that it needs a BIG box. The box needs to be soo big you can fit 2 sealed UM18 in the same space.
That's not really a UM18 thing, it's a ported box thing. The bigger a ported box is, the bigger port it can support for a given max port length and tune, the more output it can give around tune at a reasonable port velocity. But that's the strength of a ported box, you get tons of "free" output with the same driver and same power, all it does it take up more space. Sure, you can fit 2 sealed UM18 in the same space, but then you need to buy 2 drivers and twice as much amp. That's the trade-off. Both are perfectly reasonable options with their own pros and cons.

Quote:
Originally Posted by Quetzalcoalt View Post
I don't think a single 18 in a vented box will be better at SPL than 2x18s even at the tuning frequencies.
Actually, it's very easy to design a vented box that crushes its 2x sealed equivalent. My subs, for example, are more like 9x sealed at tune.

Quote:
Originally Posted by Quetzalcoalt View Post
Keep in mind that sealed really benefits from room gain.
As others have said, all subs do.

Quote:
Originally Posted by Quetzalcoalt View Post
With this new invention called the BOSS and all of its variations you don't even need anything under 18hz, unless you want to "feel" the bass while you hear your hours rattle.
Quote:
Originally Posted by Quetzalcoalt View Post
I just finished building 2xUM18 in sealed boxes. I didn't need to boost the low end i had to reduce massive peaks (14db at 30hz), at the end i'm flat down to 18hz.
You can't tell anyone what they "need", and are you drawing the line at 18Hz for any particular reason, or just because your system happens to be flat to 18Hz? Having TR doesn't change the fact that SPL <18Hz adds a lot to the experience. SPL is still really impactful down to 10-12Hz in my testing, even at levels that aren't house noise city. I'm sure you're really happy with your system, but trust me, it can be better. BTW, if anything, TR is more of a point toward ported because the single digits, which is arguably the biggest strength of sealed, becomes far less relevant with TR.

Quote:
Originally Posted by Quetzalcoalt View Post
Another plus is the group delay, or the so called how fast a sub is. Everyone says sealed is always faster than vented.
Now you're just losing credibility.

Quote:
Originally Posted by Quetzalcoalt View Post
I haven't heard subs at this caliber in a vented box so i can't speak for myself.
Now that's more like it!

Quote:
Originally Posted by ifixtheinternet View Post
By adding a 2nd equal sub, you can expect only 3db gain.
6dB. You make some good points in your post, though.

Quote:
Originally Posted by Trimlock View Post
I still think the bigger advantage of sealed subs is the slope, ported starts to rise in distortion fast post tuning and unless you are boosting the low end on a sealed you won't be seeing too high distortion there.
Come on. Are you really comparing distortion below tune? Are you really comparing anything below tune? Within the passband, where it actually matters, ported will generally have less distortion than sealed because it will have more headroom. You obviously like sealed but I would encourage you to stick to the real benefits of sealed such as size and single-digit output when trying to sell it to others.
CallingMrBenzo and automata21 like this.

Take the Red Pill (BassEQ) BassEQ Demo Clips TR Curves
Video: Sony 85" X900F @ 80" eyes-to-screen (49.4° viewing angle)
Audio: Denon AVR-X4400H 7.2.4 Atmos
Mains: Fusion-15 LR, Fusion-8 Center, Ported Volt-10 Surrounds, Custom 45°/45° Double-Angled Ported Volt-6 Atmos
Subs: The Two Towers (HT18 32cf 11.5Hz x 2), UM18 4cf x 2, Crowson MAs x 4
aron7awol is offline  
Sponsored Links
Advertisement
 
Reply DIY Speakers and Subs

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