DIY Subwoofer considerations - AVS Forum | Home Theater Discussions And Reviews
Forum Jump: 
 2Likes
Reply
 
Thread Tools
post #1 of 41 Old 01-08-2020, 11:20 AM - Thread Starter
5js
Member
 
5js's Avatar
 
Join Date: Mar 2012
Posts: 24
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 11 Post(s)
Liked: 10
DIY Subwoofer considerations

I have a home theater with the specific components listed below in my signature. The speakers are okay, but the sub lacks a lot, especially for home theater use. I use the system at 50% HT / 50% Music. Note: pics taken from the MLP.

I would like to build a diy sub, just undecided on what I want to build. Couples of options that I am considering are a pair of VBSS’s placed on their side under the L & R speakers (I would place the L&R RT15i’s on top of the VBSS's). The other option is doing an IB build using a single FI IB318 (with an option to install a second when I can afford). The IB would be installed in the corner cabinets on the right in the 2nd pic below (this would vent to the basement below). With either option I plan on getting a Behringer NX3000D (w/DSP).

I have attached a sketch of the house layout below as I’m not sure how I should calculate the volume. If I just use the “living room” area, it would be ~1928cu ft (18’ 9” x 13’ 5”, x 7’8”). Also not sure how much sound I need from the sub. Normally I have the Onkyo set about -20dB, max may be around -10dB. I’m not sure I measured correctly, but using a phone app I measure a 70-75dB at the MLP when set at -20dB or 85-90dB when set at -10dB.

I would like to keep this around $600 (inc. amp) as I am hoping to replace the Receiver, and maybe the other speakers in the near future. What should I consider in making a decision? Are there other recommended options? Are there preliminary measurements I can take to assist with the decision? (note I do have, but have not used, REW and a calibrated UMIK-1. The PC to the left under the TV is integrated into the system).






Attached Thumbnails
Click image for larger version

Name:	IMG_5105.jpg
Views:	122
Size:	166.2 KB
ID:	2666402   Click image for larger version

Name:	IMG_5106.jpg
Views:	124
Size:	214.0 KB
ID:	2666404   Click image for larger version

Name:	Layout.PNG
Views:	124
Size:	268.9 KB
ID:	2666406  

REC: Onkyo TX-NR609, HDR TV: Vizio M658-G1
L/R: Polk RT15i , C: Polk 245i , SL/SR: Polk Rt15i , SUB: Polk PSW-250
5js is offline  
Sponsored Links
Advertisement
 
post #2 of 41 Old 01-08-2020, 01:53 PM
AVS Forum Special Member
 
JohnDean's Avatar
 
Join Date: Jul 2012
Location: Franklin, TN
Posts: 1,450
Mentioned: 28 Post(s)
Tagged: 0 Thread(s)
Quoted: 566 Post(s)
Liked: 262
The best thing to do would be to put your sub in your MLP and then measure around the room to find the best response and put the new sub there. Given the layout, I can't see you putting 2 VBSS under your L&R. I also wouldn't waste my time with 1 IB sub. Your room volume would be calculated using the LR, Kitchen and hallway. Basically all open space(s)

Could you build a sub into the space under the shelf, where you marked for IB?(in place of the 2 lower doors)
How about in front of that air freshener?
Are you going to remove the Polk when you get new subs?

How big of a cabinet can you build/have? That would help with a sub recommendation. $250sub, $300amp and materials, would be right at your budget.
JohnDean is online now  
post #3 of 41 Old 01-08-2020, 01:57 PM
Senior Member
 
Join Date: Mar 2018
Posts: 203
Mentioned: 2 Post(s)
Tagged: 0 Thread(s)
Quoted: 280 Post(s)
Liked: 128
wookiegr is online now  
Sponsored Links
Advertisement
 
post #4 of 41 Old 01-08-2020, 02:23 PM
Advanced Member
 
Join Date: Aug 2014
Posts: 548
Mentioned: 62 Post(s)
Tagged: 0 Thread(s)
Quoted: 267 Post(s)
Liked: 335
I don't know if you would be interested in moving your couch off the wall about 10-12 inches... But you could always grab 4 or 8 of the $30 JBL subs and build a few boxes to put behind the couch. That would probably give you the most spl for the money I would think, especially with how open you space is. Say $140-280 for the subs after tax, then grab an iNuke 3000 or 6000 depending on how many you go with, and you've got yourself a heck of an upgrade. Hard part is waiting for them to go on sale... No telling when they will again. Just a thought. Check out the JBL thread Here

Blister64 Full Basement Build Panasonic PT-AE8000U | Yamaha RX-A3070 | Emotiva XPA-7 Gen3 | DIY Sound Group Ported 1299 TMWW Front Stage | DIY SG Volt 10 Surrounds | Monoprice 8" Alpha In-ceiling Atmos | Three Stereo Integrity HS-24 mkIII's sealed | Sinbosen FP20000Q
YouTube Channel for builds and reviews Life Of Bliss YouTube
blister64 is offline  
post #5 of 41 Old 01-09-2020, 05:21 AM - Thread Starter
5js
Member
 
5js's Avatar
 
Join Date: Mar 2012
Posts: 24
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 11 Post(s)
Liked: 10
Quote:
Originally Posted by JohnDean View Post
The best thing to do would be to put your sub in your MLP and then measure around the room to find the best response and put the new sub there. Given the layout, I can't see you putting 2 VBSS under your L&R. I also wouldn't waste my time with 1 IB sub. Your room volume would be calculated using the LR, Kitchen and hallway. Basically all open space(s)
I can do that. What would I be looking for "best response"? The most boost?

Quote:
Originally Posted by JohnDean View Post
Could you build a sub into the space under the shelf, where you marked for IB?(in place of the 2 lower doors)
How about in front of that air freshener?
Yes, I could build a sub into the space under the shelf. That's where I would build an IB if that's what I end up doing. If I were to do that I would install a manifold that would accept two IB's but would start with one till I could afford a second. I could put a sub in front of the outlet as well, but if I am not going with an IB and was going to have a box or boxes, my initial preference would be two boxes under the L & R speakers. But, I'm not hard over on that and could go with a single box located somewhere else. Why do you not recommend the two VBSS's or an IB?

Quote:
Originally Posted by JohnDean View Post
Are you going to remove the Polk when you get new subs?
Yes. That would be the plan. That sub only has a 8" driver and just just work for movies.


Quote:
Originally Posted by JohnDean View Post
How big of a cabinet can you build/have? That would help with a sub recommendation. $250sub, $300amp and materials, would be right at your budget.
Well, I could build one as big as a refrigerator, but would prefer not to go that way.

REC: Onkyo TX-NR609, HDR TV: Vizio M658-G1
L/R: Polk RT15i , C: Polk 245i , SL/SR: Polk Rt15i , SUB: Polk PSW-250
5js is offline  
post #6 of 41 Old 01-09-2020, 05:23 AM - Thread Starter
5js
Member
 
5js's Avatar
 
Join Date: Mar 2012
Posts: 24
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 11 Post(s)
Liked: 10
Quote:
Originally Posted by wookiegr View Post
Aren't those pics of your living room?
Yes. I just wasn't sure if I needed to include the dining room/kitchen and hallways in my calculations for volume as they are open to the sound.

REC: Onkyo TX-NR609, HDR TV: Vizio M658-G1
L/R: Polk RT15i , C: Polk 245i , SL/SR: Polk Rt15i , SUB: Polk PSW-250
5js is offline  
post #7 of 41 Old 01-09-2020, 05:28 AM - Thread Starter
5js
Member
 
5js's Avatar
 
Join Date: Mar 2012
Posts: 24
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 11 Post(s)
Liked: 10
Quote:
Originally Posted by blister64 View Post
I don't know if you would be interested in moving your couch off the wall about 10-12 inches... But you could always grab 4 or 8 of the $30 JBL subs and build a few boxes to put behind the couch. That would probably give you the most spl for the money I would think, especially with how open you space is. Say $140-280 for the subs after tax, then grab an iNuke 3000 or 6000 depending on how many you go with, and you've got yourself a heck of an upgrade. Hard part is waiting for them to go on sale... No telling when they will again. Just a thought. Check out the JBL thread Here
Couch is currently off the wall 19", so that would be a possibility. I check the linked thread out. (behind the couch is a picture window with vertical blinds so I have my surrounds on the floor behind the couch firing upwards).

EDIT: Reading through a few pages of that post I read references to near field subwoofer. Is that type of sub more the feel of LFE (visceral feel) or is sound quality just as good? I ask because I would trade sound quality of the subwoofer over visceral feel. Reading more posts I think this is referred to in the posts as TR (?).

REC: Onkyo TX-NR609, HDR TV: Vizio M658-G1
L/R: Polk RT15i , C: Polk 245i , SL/SR: Polk Rt15i , SUB: Polk PSW-250

Last edited by 5js; 01-09-2020 at 07:34 AM.
5js is offline  
post #8 of 41 Old 01-09-2020, 11:32 AM
Advanced Member
 
Join Date: Aug 2014
Posts: 548
Mentioned: 62 Post(s)
Tagged: 0 Thread(s)
Quoted: 267 Post(s)
Liked: 335
Quote:
Originally Posted by 5js View Post
Couch is currently off the wall 19", so that would be a possibility. I check the linked thread out. (behind the couch is a picture window with vertical blinds so I have my surrounds on the floor behind the couch firing upwards).

EDIT: Reading through a few pages of that post I read references to near field subwoofer. Is that type of sub more the feel of LFE (visceral feel) or is sound quality just as good? I ask because I would trade sound quality of the subwoofer over visceral feel. Reading more posts I think this is referred to in the posts as TR (?).
I mean you are definitely going to get the visceral effect with them being closer, but I can't speak as much on the sound quality. I've experienced near field subs before, and I didn't think they sounded bad at all. There were 5 UM18s under the screen and 3 UM18s right behind the seating. That experience was a turning point for me... Showed me what was possible in a home theater! You could always put 4 up front (2 on either side of tv) and then 4 along the back of the couch in a line. Would make the box lower for you to set your surrounds on and give you both a regular sub placement as well as near field. Good thing about those subs is there are lots of options you can look at since they are so cheap. And since you already have the room back there, you're not looking to alter your space at all to fit them.

There are some real believers in those JBLs though, lots of people only use those and say they are extremely happy. I'll know soon enough, I have 16 waiting for me to build boxes for behind my couch

Blister64 Full Basement Build Panasonic PT-AE8000U | Yamaha RX-A3070 | Emotiva XPA-7 Gen3 | DIY Sound Group Ported 1299 TMWW Front Stage | DIY SG Volt 10 Surrounds | Monoprice 8" Alpha In-ceiling Atmos | Three Stereo Integrity HS-24 mkIII's sealed | Sinbosen FP20000Q
YouTube Channel for builds and reviews Life Of Bliss YouTube
blister64 is offline  
post #9 of 41 Old 01-09-2020, 01:24 PM
AVS Forum Special Member
 
JohnDean's Avatar
 
Join Date: Jul 2012
Location: Franklin, TN
Posts: 1,450
Mentioned: 28 Post(s)
Tagged: 0 Thread(s)
Quoted: 566 Post(s)
Liked: 262
Quote:
Originally Posted by 5js View Post
I can do that. What would I be looking for "best response"? The most boost?



Why do you not recommend the two VBSS's or an IB?
You'd be looking for the place with the flattest overall response. Then if you put your sub in that location the MLP would have the best response.

VBSS is more of a midbass driver. I'd recommend it if you were adding to existing subs that already produced 30hz and below. As far as IB, I just think you'd be underwhelmed with that much open space and only 2 drivers.

That's a clean looking room, It appears to me if you put them up front under your L&R they'd be sticking way out into the walkway infront of the TV.
JohnDean is online now  
post #10 of 41 Old 01-10-2020, 11:31 AM - Thread Starter
5js
Member
 
5js's Avatar
 
Join Date: Mar 2012
Posts: 24
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 11 Post(s)
Liked: 10
Quote:
Originally Posted by JohnDean View Post
You'd be looking for the place with the flattest overall response. Then if you put your sub in that location the MLP would have the best response.
Thanks for the response. I am hoping to spend some time this weekend learning REW and getting some general characteristics of my room (reflections, etc). I will be testing different sub locations as suggested.

Quote:
Originally Posted by JohnDean View Post
VBSS is more of a midbass driver. I'd recommend it if you were adding to existing subs that already produced 30hz and below. As far as IB, I just think you'd be underwhelmed with that much open space and only 2 drivers.
The current Polk PSW-250 just isn't cutting it for music and especially HT. It's only 50W with an 8" woofer and rated frequency response is 40-160 Hz. Not sure how much SPL i'm getting, but I suspect not a lot. What frequency response could I expect with the VBSS? What other diy sub would you recommend for ~$300 that would meet my needs of clean audio for music and still supporting LFE for HT? I do want something with adequate SPL but don't need to blow my windows out.

Quote:
Originally Posted by JohnDean View Post
That's a clean looking room, It appears to me if you put them up front under your L&R they'd be sticking way out into the walkway infront of the TV.
Yea, that is the same concern I am having. I just don't think two VBSS would look balanced in that location. By the outlet / notional IB install area isn't ideal either (depending on the size) as that would be where the Christmas tree is in the pic below. The only other place I can think of for a larger box would be at the end of the couch where the current sub is. The only concern is that there is a picture window (w/vertical blinds) behind the couch.

So - my options are boxes under the L & R speakers - but that wouldn't look real clean. An IB integrated into the cabinets on the end wall. A large box where the Christmas Tree is or at the end of the couch (If I were to use these locations I would like disguise the sub in some fashion - but that would depend on what size box I need.) I also think I could fit a large but really skinny box behind the couch - but I'm not sure this would be good for music. I have even considered a thin tapped horn (something like a Tangband Tapped Horn)

I think my next step is to figure out if I can make an IB work, or if not an IB, what diy sub is recommend with my requirements and budget - and then decide what I can do to integrate the box into the living room.

Attached Thumbnails
Click image for larger version

Name:	IMG_5112.JPG
Views:	77
Size:	109.2 KB
ID:	2667548  

REC: Onkyo TX-NR609, HDR TV: Vizio M658-G1
L/R: Polk RT15i , C: Polk 245i , SL/SR: Polk Rt15i , SUB: Polk PSW-250
5js is offline  
post #11 of 41 Old 01-10-2020, 11:34 AM - Thread Starter
5js
Member
 
5js's Avatar
 
Join Date: Mar 2012
Posts: 24
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 11 Post(s)
Liked: 10
Quote:
Originally Posted by blister64 View Post
I mean you are definitely going to get the visceral effect with them being closer, but I can't speak as much on the sound quality. I've experienced near field subs before, and I didn't think they sounded bad at all. There were 5 UM18s under the screen and 3 UM18s right behind the seating. That experience was a turning point for me... Showed me what was possible in a home theater! You could always put 4 up front (2 on either side of tv) and then 4 along the back of the couch in a line. Would make the box lower for you to set your surrounds on and give you both a regular sub placement as well as near field. Good thing about those subs is there are lots of options you can look at since they are so cheap. And since you already have the room back there, you're not looking to alter your space at all to fit them.

There are some real believers in those JBLs though, lots of people only use those and say they are extremely happy. I'll know soon enough, I have 16 waiting for me to build boxes for behind my couch
If I see the JBL's on sale I'm going to grab some. If I don't end up using them on this system I can use them in my den in the basement.

REC: Onkyo TX-NR609, HDR TV: Vizio M658-G1
L/R: Polk RT15i , C: Polk 245i , SL/SR: Polk Rt15i , SUB: Polk PSW-250

Last edited by 5js; 01-10-2020 at 12:00 PM.
5js is offline  
post #12 of 41 Old 01-10-2020, 11:50 AM
AVS Forum Special Member
 
JohnDean's Avatar
 
Join Date: Jul 2012
Location: Franklin, TN
Posts: 1,450
Mentioned: 28 Post(s)
Tagged: 0 Thread(s)
Quoted: 566 Post(s)
Liked: 262
Based on what you have now, I think a Ultimax 18 in a 4cuft sealed box would be impressive to you. A 22" cube is relatively small compared to ported options and you could add another one later if you wanted. I have no doubt a VBSS would be better than what you have, I just prefer the 15-30hz range for HT and the VBSS is rolling off by that point.

I've always wanted to try an IB, but the general idea is that it takes several more drivers to get the same performance you get with sealed or ported. I'd say in your room you'd want 4 IB drivers to start coming close to what you'd get from the other alignments.
jevchance likes this.
JohnDean is online now  
post #13 of 41 Old 01-10-2020, 12:04 PM - Thread Starter
5js
Member
 
5js's Avatar
 
Join Date: Mar 2012
Posts: 24
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 11 Post(s)
Liked: 10
Quote:
Originally Posted by JohnDean View Post
Based on what you have now, I think a Ultimax 18 in a 4cuft sealed box would be impressive to you. A 22" cube is relatively small compared to ported options and you could add another one later if you wanted. I have no doubt a VBSS would be better than what you have, I just prefer the 15-30hz range for HT and the VBSS is rolling off by that point.

I've always wanted to try an IB, but the general idea is that it takes several more drivers to get the same performance you get with sealed or ported. I'd say in your room you'd want 4 IB drivers to start coming close to what you'd get from the other alignments.
Thanks for the response. I had looked at the Ultimax 18 as well. Guess I should put that back on my list of options. I do like the thought that I could integrate an IB and not see it - but the 18" drivers are close to $300 each...

REC: Onkyo TX-NR609, HDR TV: Vizio M658-G1
L/R: Polk RT15i , C: Polk 245i , SL/SR: Polk Rt15i , SUB: Polk PSW-250
5js is offline  
post #14 of 41 Old 01-10-2020, 01:00 PM
Advanced Member
 
Join Date: Aug 2014
Posts: 548
Mentioned: 62 Post(s)
Tagged: 0 Thread(s)
Quoted: 267 Post(s)
Liked: 335
Quote:
Originally Posted by 5js View Post
If I see the JBL's on sale I'm going to grab some. If I don't end up using them on this system I can use them in my den in the basement.
Not a bad idea. Yea I figured even if I don't end up using these in my next space (looking to move in a year) they were cheap enough that I could throw them in other areas for a nice boost. I would look into the "magic cube", which just means you are able to wire the subs back to 4 ohms after hooking up multiples. The cube is like 2x2, 3x3, 4x4... and so on. So essentially 4, 9, 16 drivers can all be wired back to a 4 ohm load when done correctly. You can do it with 8 drivers as well if I remember correctly. Just do some research/planning before you buy them

Blister64 Full Basement Build Panasonic PT-AE8000U | Yamaha RX-A3070 | Emotiva XPA-7 Gen3 | DIY Sound Group Ported 1299 TMWW Front Stage | DIY SG Volt 10 Surrounds | Monoprice 8" Alpha In-ceiling Atmos | Three Stereo Integrity HS-24 mkIII's sealed | Sinbosen FP20000Q
YouTube Channel for builds and reviews Life Of Bliss YouTube
blister64 is offline  
post #15 of 41 Old 01-13-2020, 05:17 AM - Thread Starter
5js
Member
 
5js's Avatar
 
Join Date: Mar 2012
Posts: 24
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 11 Post(s)
Liked: 10
Quote:
Originally Posted by JohnDean View Post
You'd be looking for the place with the flattest overall response. Then if you put your sub in that location the MLP would have the best response.
First time using REW. Tried the sub in various location around the living room. By the left speaker seemed to show the flattest response, but I wanted to post all the graphs as I'm not positive what I'm looking for. The first graph shows the original sub location at the end of the couch in green, the sub by the L speaker in red, and by the R speaker in blue. I did notice that by the L speaker I have a bit of a boost at 38Hz and a sharp notch at 82Hz (whereas by the R speaker the notch is at 98Hz). I also included a waterfall with the sub at the L speaker. All of the waterfall show the ridge at 38Hz. Seems like my room like to resonate at that freq. Finally, I have an RTA graph of the noise floor before taking measurements. (not sure what the 90Hz line is but it was always there).

I understand the characteristics will most likely change if I had a sub that went a little lower (likely would excite other room modals), but if there anything I can glean from these tests? Are there other things I should look at to evaluate the sub and locations?

The original Sub location at end of couch and by each front speaker (positions 1, 5, 6)



Sub inside notional IB cabinet (position 2)


Sub just outside IB cabinet (position 3)


Sub by outlet near IB cabinet (position 4)


Sub by R speaker (position 5)


Sub by L speaker (position 6)


Sub by hallway outlet (position 7)


Sub in "coffee table" location (position 8)


Sub by L speaker waterfall (at position 6)


Noise floor RTA
Attached Thumbnails
Click image for larger version

Name:	Sub end of couch - original location.jpg
Views:	11
Size:	152.5 KB
ID:	2669146   Click image for larger version

Name:	Sub inside IB cabinet.jpg
Views:	73
Size:	152.3 KB
ID:	2669148   Click image for larger version

Name:	Sub just outside IB cabinet.jpg
Views:	71
Size:	150.8 KB
ID:	2669150   Click image for larger version

Name:	Sub by  outlet near IB.jpg
Views:	74
Size:	152.7 KB
ID:	2669152   Click image for larger version

Name:	Sub by R speaker.jpg
Views:	71
Size:	152.1 KB
ID:	2669154  

Click image for larger version

Name:	Sub by L speaker.jpg
Views:	74
Size:	153.1 KB
ID:	2669156   Click image for larger version

Name:	Sub by hallway outlet.jpg
Views:	78
Size:	160.8 KB
ID:	2669158   Click image for larger version

Name:	sub coffee table locaton.jpg
Views:	76
Size:	150.0 KB
ID:	2669160   Click image for larger version

Name:	Sub overlay L R Orig.jpg
Views:	74
Size:	230.5 KB
ID:	2669162   Click image for larger version

Name:	Sub Left no trap Waterfalls.jpg
Views:	74
Size:	418.7 KB
ID:	2669164  

Click image for larger version

Name:	Initial Noise Floor RTA 1-11-2020 daytime.jpg
Views:	72
Size:	262.6 KB
ID:	2669166  

REC: Onkyo TX-NR609, HDR TV: Vizio M658-G1
L/R: Polk RT15i , C: Polk 245i , SL/SR: Polk Rt15i , SUB: Polk PSW-250

Last edited by 5js; 01-13-2020 at 06:50 AM.
5js is offline  
post #16 of 41 Old 01-13-2020, 06:52 AM - Thread Starter
5js
Member
 
5js's Avatar
 
Join Date: Mar 2012
Posts: 24
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 11 Post(s)
Liked: 10
To show sub locations tested

Attached Thumbnails
Click image for larger version

Name:	Capture.PNG
Views:	67
Size:	24.1 KB
ID:	2669200  

REC: Onkyo TX-NR609, HDR TV: Vizio M658-G1
L/R: Polk RT15i , C: Polk 245i , SL/SR: Polk Rt15i , SUB: Polk PSW-250
5js is offline  
post #17 of 41 Old 01-13-2020, 08:57 AM
AVS Forum Special Member
 
Augerhandle's Avatar
 
Join Date: Jan 2009
Location: About 25" away from my computer screen
Posts: 5,577
Mentioned: 37 Post(s)
Tagged: 0 Thread(s)
Quoted: 1392 Post(s)
Liked: 1353
Those sharp downward spikes shown in the 4th, 5th, 6th, and 7th graphs are likely phase issues. Re-run the sweeps with reversed polarity, and then you can tweak the response with delay settings.

"The wise understand by themselves; fools follow the reports of others"-Tibetan Proverb
_____________________ http://www.scientificamerican.com/article/auger-handle/ ________________________

Last edited by Augerhandle; 01-14-2020 at 11:06 AM.
Augerhandle is offline  
post #18 of 41 Old 01-13-2020, 09:20 AM - Thread Starter
5js
Member
 
5js's Avatar
 
Join Date: Mar 2012
Posts: 24
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 11 Post(s)
Liked: 10
Quote:
Originally Posted by Augerhandle View Post
Those sharp downward spikes shown in the 4th, 5th, 6th, and 7th graphs are likely phase issues. Re-run the sweeps with reversed phase, and then you can tweak the response with delay settings.
I will reverse phase and re-run to see what it looks like.

What do you mean by tweak the response with delay setting? What difference is the response would I look for? I'm going to replace the sub anyway, but I am interested in learning what changes affect what.

REC: Onkyo TX-NR609, HDR TV: Vizio M658-G1
L/R: Polk RT15i , C: Polk 245i , SL/SR: Polk Rt15i , SUB: Polk PSW-250
5js is offline  
post #19 of 41 Old 01-13-2020, 09:28 AM
AVS Forum Special Member
 
Augerhandle's Avatar
 
Join Date: Jan 2009
Location: About 25" away from my computer screen
Posts: 5,577
Mentioned: 37 Post(s)
Tagged: 0 Thread(s)
Quoted: 1392 Post(s)
Liked: 1353
Quote:
Originally Posted by 5js View Post
I will reverse phase and re-run to see what it looks like.

What do you mean by tweak the response with delay setting? What difference is the response would I look for? I'm going to replace the sub anyway, but I am interested in learning what changes affect what.

Sorry, I forgot you have a store bought sub. When you build a sub, you can use the software in the amp to adjust the delay, which in effect fine tunes the phase relationship between speakers. Reversing polarity adjusts phase by 180° only, which may or may not improve the response curve.

"The wise understand by themselves; fools follow the reports of others"-Tibetan Proverb
_____________________ http://www.scientificamerican.com/article/auger-handle/ ________________________

Last edited by Augerhandle; 01-14-2020 at 12:01 PM. Reason: Edited for clarity (phase vs polarity)
Augerhandle is offline  
post #20 of 41 Old 01-13-2020, 09:31 AM - Thread Starter
5js
Member
 
5js's Avatar
 
Join Date: Mar 2012
Posts: 24
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 11 Post(s)
Liked: 10
Quote:
Originally Posted by Augerhandle View Post
Sorry, I forgot you have a store bought sub. When you build a sub, you can use the software in the amp to adjust the delay, which in effect fine tunes the phase relationship between speakers. Reversing polarity reverses phase by 180° only, which may or may not improve the response curve.
Gotcha. Well, I do the phase test just to see how it affects the response. Once I decide what sub to build and get a separate amp I'm sure I'll learn a lot more about the software settings to eq the sub.

REC: Onkyo TX-NR609, HDR TV: Vizio M658-G1
L/R: Polk RT15i , C: Polk 245i , SL/SR: Polk Rt15i , SUB: Polk PSW-250
5js is offline  
post #21 of 41 Old 01-13-2020, 01:09 PM - Thread Starter
5js
Member
 
5js's Avatar
 
Join Date: Mar 2012
Posts: 24
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 11 Post(s)
Liked: 10
Quote:
Originally Posted by JohnDean View Post
Based on what you have now, I think a Ultimax 18 in a 4cuft sealed box would be impressive to you. A 22" cube is relatively small compared to ported options and you could add another one later if you wanted. I have no doubt a VBSS would be better than what you have, I just prefer the 15-30hz range for HT and the VBSS is rolling off by that point.
John - how does the Ultimax in a 4cuft sealed box compare with some of the ported builds using this driver (mini marty, etc.)?

REC: Onkyo TX-NR609, HDR TV: Vizio M658-G1
L/R: Polk RT15i , C: Polk 245i , SL/SR: Polk Rt15i , SUB: Polk PSW-250
5js is offline  
post #22 of 41 Old 01-13-2020, 07:39 PM
Member
 
joker927's Avatar
 
Join Date: Mar 2014
Posts: 72
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 56 Post(s)
Liked: 35
I didn't read every post but saw your couch was 19" away from wall. At least one user in the VBSS design thread has a thin design that might be just what you need.
joker927 is offline  
post #23 of 41 Old 01-14-2020, 07:56 AM
AVS Forum Special Member
 
desertdome's Avatar
 
Join Date: Aug 2004
Location: Omaha, NE
Posts: 3,796
Mentioned: 325 Post(s)
Tagged: 0 Thread(s)
Quoted: 1546 Post(s)
Liked: 1847
Quote:
Originally Posted by Augerhandle View Post
. . . Reversing polarity reverses phase by 180° only
Phase is a time function and cannot be "reversed." Only polarity can be reversed.

Ponderosa Theater
High Impact AV
- ISF Level III Video Calibrator, THX-HAA HT3 Audio Designer/Calibrator
-StormAudio ISP 3D.32 Elite AVB; Cherry Megaschino amps; JTR Speakers Noesis 215RM's (5), S8's (10), & Captivator S2's (4); JTR NX7; Lumagen 4442; JRiver Media Center
desertdome is online now  
post #24 of 41 Old 01-14-2020, 09:18 AM - Thread Starter
5js
Member
 
5js's Avatar
 
Join Date: Mar 2012
Posts: 24
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 11 Post(s)
Liked: 10
Quote:
Originally Posted by desertdome View Post
Phase is a time function and cannot be "reversed." Only polarity can be reversed.
changing the subs polarity from 0 to 180 will invert the phase, correct? (still have a LOT to learn - just want to make sure I'm an understanding things so far - phase is one area I haven't spent much time trying to understand - but plan to in the near future).

REC: Onkyo TX-NR609, HDR TV: Vizio M658-G1
L/R: Polk RT15i , C: Polk 245i , SL/SR: Polk Rt15i , SUB: Polk PSW-250
5js is offline  
post #25 of 41 Old 01-14-2020, 09:42 AM
AVS Forum Special Member
 
Join Date: Jul 2014
Posts: 4,763
Mentioned: 480 Post(s)
Tagged: 0 Thread(s)
Quoted: 3073 Post(s)
Liked: 13092
Quote:
Originally Posted by Augerhandle View Post
Those sharp downward spikes shown in the 4th, 5th, 6th, and 7th graphs are likely phase issues. Re-run the sweeps with reversed phase, and then you can tweak the response with delay settings.
If they are single sub-only sweeps, which they appear to be, then adjusting phase should make no difference since there is no phase interaction with other speakers or subs.

Take the Red Pill (BassEQ) BassEQ Demo Clips
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 online now  
post #26 of 41 Old 01-14-2020, 10:20 AM
AVS Forum Special Member
 
desertdome's Avatar
 
Join Date: Aug 2004
Location: Omaha, NE
Posts: 3,796
Mentioned: 325 Post(s)
Tagged: 0 Thread(s)
Quoted: 1546 Post(s)
Liked: 1847
Quote:
Originally Posted by 5js View Post
changing the subs polarity from 0 to 180 will invert the phase, correct? (still have a LOT to learn - just want to make sure I'm an understanding things so far - phase is one area I haven't spent much time trying to understand - but plan to in the near future).
That is not correct. Here is one fairly simple explanation: Polarity? Phase? What is the difference?

One technique to mic a snare drum is to have one mic above the drum head and one below the drum head. The polarity of the under head mic needs to be reversed relative to the top mic because the wave from the bottom of the drum head is opposite the top of the drum head. If the microphones are at different distances, the waveforms are being recorded at different times relative to each other. They are out of phase - one waveform is delayed vs the other. You align their phase by adding delay to the closer microphone. You can see that changing the polarity does nothing to help with the phase issue. Changing polarity is one tool that changes how waveforms interact with each.

Ponderosa Theater
High Impact AV
- ISF Level III Video Calibrator, THX-HAA HT3 Audio Designer/Calibrator
-StormAudio ISP 3D.32 Elite AVB; Cherry Megaschino amps; JTR Speakers Noesis 215RM's (5), S8's (10), & Captivator S2's (4); JTR NX7; Lumagen 4442; JRiver Media Center
desertdome is online now  
post #27 of 41 Old 01-14-2020, 10:56 AM
AVS Forum Special Member
 
Augerhandle's Avatar
 
Join Date: Jan 2009
Location: About 25" away from my computer screen
Posts: 5,577
Mentioned: 37 Post(s)
Tagged: 0 Thread(s)
Quoted: 1392 Post(s)
Liked: 1353
Quote:
Originally Posted by desertdome View Post
Phase is a time function and cannot be "reversed." Only polarity can be reversed.
Poor wording on my part (to be fair, it is shown as a "Phase" switch on my amp). I stand corrected, and will edit my post. Thank you.

"The wise understand by themselves; fools follow the reports of others"-Tibetan Proverb
_____________________ http://www.scientificamerican.com/article/auger-handle/ ________________________

Last edited by Augerhandle; 01-14-2020 at 11:08 AM.
Augerhandle is offline  
post #28 of 41 Old 01-14-2020, 11:05 AM
AVS Forum Special Member
 
Augerhandle's Avatar
 
Join Date: Jan 2009
Location: About 25" away from my computer screen
Posts: 5,577
Mentioned: 37 Post(s)
Tagged: 0 Thread(s)
Quoted: 1392 Post(s)
Liked: 1353
Quote:
Originally Posted by aron7awol View Post
If they are single sub-only sweeps, which they appear to be, then adjusting phase should make no difference since there is no phase interaction with other speakers or subs.
Agreed, except I strongly suspect he is running the sweeps with all speakers connected.

"The wise understand by themselves; fools follow the reports of others"-Tibetan Proverb
_____________________ http://www.scientificamerican.com/article/auger-handle/ ________________________
Augerhandle is offline  
post #29 of 41 Old 01-14-2020, 11:12 AM - Thread Starter
5js
Member
 
5js's Avatar
 
Join Date: Mar 2012
Posts: 24
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 11 Post(s)
Liked: 10
Quote:
Originally Posted by Augerhandle View Post
Agreed, except I strongly suspect he is running the sweeps with all speakers connected.
unsure what you mean by connected. There is only one sub and each sweep was done one speaker at a time.

REC: Onkyo TX-NR609, HDR TV: Vizio M658-G1
L/R: Polk RT15i , C: Polk 245i , SL/SR: Polk Rt15i , SUB: Polk PSW-250
5js is offline  
post #30 of 41 Old 01-14-2020, 11:23 AM
AVS Forum Special Member
 
Augerhandle's Avatar
 
Join Date: Jan 2009
Location: About 25" away from my computer screen
Posts: 5,577
Mentioned: 37 Post(s)
Tagged: 0 Thread(s)
Quoted: 1392 Post(s)
Liked: 1353
Quote:
Originally Posted by 5js View Post
unsure what you mean by connected. There is only one sub and each sweep was done one speaker at a time.
Were your other speakers disconnected?

"The wise understand by themselves; fools follow the reports of others"-Tibetan Proverb
_____________________ http://www.scientificamerican.com/article/auger-handle/ ________________________
Augerhandle 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