Adding a pair of SVS SB3000 R Evolution subs to my system

[Daverich4]

I have a conventional 2 channel stereo with a separate preamplifier and amplifier. In several other threads I've gotten a lot of advice and help in placing my speakers & MLP as well as room treatments. I still have a couple of deep nulls left that I'm going to try and correct by adding a pair of subwoofers. My initial placement is going to be at the center spot on each side wall which is one of the suggested positions by Harman and SVS. There are other suggested positions I'm going to try and I've already done a casual sub crawl. For one reason or another, perhaps the shape of my room, the Roon Room Simulator doesn't seem to give results that match the actual measurements so I'm no longer trying to use that. I don't want to spend a lot of time trying out and experimenting with different things only to post here and find out nothing I'm doing is useful. With that in mind, I'm starting with one sub centered on the right wall. I'm driving the subwoofers with the unbalanced outs on the preamp. I'm using the settings SVS suggested for my speakers (Wilson Audio Sasha ll's). They recommended a Low Pass Filter Frequency of 50 Hz and a Low Pass Filter Slope of 24 dB/octave.

I started out with this process by @Keith_W.

1. Set up the mic at the listening position.
2. Set up REW's generator to play pink noise from ALL the speakers.
3. Pull up REW's RTA view.
4. Adjust the phase of your subwoofer until the RTA is as flat as possible.

@staticV3 helped me with the settings for the Generator and RTA

The SVS subs can change Phase 1 degree at a time but I only tried 0 & 180. Again, because I want to make sure the process is right before I spend a lot of time on it. To me Phase 0 looked better so that's what I went with. The subs also have optional Auto EQ built into them. I tried both ways and the frequency response of the Auto EQ looked better to me than the non-EQ so that's what I went with.

Actually, now that I take another look at the graph of the Mains & Sub, with and without Auto EQ, maybe the dip of the Auto EQ is worse than the peak of without. In any case, I would appreciate it if someone could take a look at this and help get me pointed in the right direction. Thanks.

 

[Flaesh]

IMO, in your case you first need to get as good a result as possible, without large holes, from just your two subs. In any arrangement. The shape of the room doesn't make things any easier. Equalization is the second task, integration with speakers is the third.
ps: not SOTA AutoEQ IMHO:

PPS: the rear left corner may make the situation worse, so you'll have to tinker with some real-life experiments.

 

[Daverich4]

IMO, in your case you first need to get as good a result as possible, without large holes, from just your two subs. In any arrangement. The shape of the room doesn't make things any easier. Equalization is the second task, integration with speakers is the third.
ps: not SOTA AutoEQ IMHO:
View attachment 551237
PPS: the rear left corner may make the situation worse, so you'll have to tinker with some real-life experiments.

I think you’re right about the Auto EQ. Thanks.

 

[Flaesh]

I don't want to spend a lot of time trying out and experimenting

But you'll have to do it without a guarantee of [absolute] success. You need to find good locations for the subwoofers. For two. Locations where they work well ever together. One friend with two subwoofers gave up this activity and put both in one place; there they summed up acoustically))

https://www.academia.edu/5362839/Perception_Modal_Control But this is also for rectangular rooms. I'm not sure how well the SSS will work with your left wall, but it seems [almost] easy to try.

 

[Daverich4]

But you'll have to do it without a guarantee of [absolute] success. You need to find good locations for the subwoofers. For two. Locations where they work well ever together. One friend with two subwoofers gave up this activity and put both in one place; there they summed up acoustically))

https://www.academia.edu/5362839/Perception_Modal_Control But this is also for rectangular rooms. I'm not sure how well the SSS will work with your left wall, but it seems [almost] easy to try.

Your quote left out the second half of it, that is I don’t want to try a bunch of things only to come here to find out I’m doing the measurements wrong or measuring the wrong things or have some other problem.

 

[Flaesh]

I've written down my opinion on what to measure and what to want. Both subwoofers separately and together. Unfortunately, a simple simulator doesn't work for this left rear area. RTA can help when actually crawling subs, ensuring there are no dips. Minimum phase peaks can be fairly well equalized later, not necessarily automatically.
I'd also try FB and, if possible (23' delay), SSS. I'd like to see how bad it is. But you may not want to sum the bass to mono.

 

[Daverich4]

I'd also try FB and, if possible (23' delay), SSS. I'd like to see how bad it is.

I’m not familiar with those terms. Could you explain what they mean?

 

[HiMu]

My initial placement is going to be at the center spot on each side wall which is one of the suggested positions by Harman and SVS. There are other suggested positions I'm going to try and I've already done a casual sub crawl. For one reason or another, perhaps the shape of my room, the Roon Room Simulator doesn't seem to give results that match the actual measurements so I'm no longer trying to use that.

Could you provide exact locations of the subs where they were when you did the measurements? And could you take measurements with only one sub at a time with crossover set to maybe 150Hz, that way it's easier to try to understand what is what from the measurements.
By Roon Room Simulator, did you mean REW Room Sim, which doesn't work with the non-shoebox shaped room you have?
The Vesa Laasanen Room mode calculator works better for odd shaped rooms, although it can't simulate the stairs and crossover frequencies.
By guesstimation of the sub locations, it matches reasonably well with your measurements:

Room Mode Calculator

Calculate room modes, standing waves, and resonant frequencies for any room shape. Free online acoustics tool with pressure mapping and source optimization.

www.vesalaasanen.com

I'd also try FB and, if possible (23' delay), SSS.

What these abbreviations mean?

 

[Daverich4]

Could you provide exact locations of the subs where they were when you did the measurements? And could you take measurements with only one sub at a time with crossover set to maybe 150Hz, that way it's easier to try to understand what is what from the measurements.
By Roon Room Simulator, did you mean REW Room Sim, which doesn't work with the non-shoebox shaped room you have?
The Vesa Laasanen Room mode calculator works better for odd shaped rooms, although it can't simulate the stairs and crossover frequencies.
By guesstimation of the sub locations, it matches reasonably well with your measurements:

Room Mode Calculator

Calculate room modes, standing waves, and resonant frequencies for any room shape. Free online acoustics tool with pressure mapping and source optimization.

www.vesalaasanen.com

View attachment 551398


What these abbreviations mean?

There was only one sub, I haven't set up the second sub yet. Therefor, the measurements are for a single sub only. The sub was at the center point of the right wall, 11 1/2 feet from the front and back walls. Yes, I misspoke about the Room Simulator. I did mean REW, not Roon.

 

[Flaesh]

What these abbreviations

Fazenda terms. A link to the most important AES paper regarding subwooferolgy (according to dallasjustice)) was above.

Vesa Laasanen Room mode calculator

Yes, it could be useful for OP, especially after comparing it with reality.

 

[Flaesh]

For illustrative and humorous purposes, here's what not to do. Adding a second subwoofer creates a nice funny hole at 50 Hz in a certain location:

 

[Daverich4]

For illustrative and humorous purposes, here's what not to do. Adding a second subwoofer creates a nice funny hole at 50 Hz in a certain location:
View attachment 551831

Thanks, I’ve done the subwoofer crawl and also gone around with a microphone. I have a number of locations marked as possibilities. I’m a little surprised at how much difference there is as I go around the room.

 

[Flaesh]

And pay attention to the summation of two subs in an asymmetrical arrangement.

 

[Daverich4]

Using @Keith_W’s system of using the REW RTA to set the phase my right channel Sub is much flatter at 180. However, changing my left channel sub from 0 to 180 doesn’t make much of a change in the RTA but I get audible beating when it’s at 180. Does it matter if the subs are set differently? The subs are placed using the sub crawl with both my ears and a microphone. Maybe try a different spot for the left channel sub? There are several other spots it could go in according to the crawl.

 

[sysfc6]

I have a conventional 2 channel stereo with a separate preamplifier and amplifier. In several other threads I've gotten a lot of advice and help in placing my speakers & MLP as well as room treatments. I still have a couple of deep nulls left that I'm going to try and correct by adding a pair of subwoofers. My initial placement is going to be at the center spot on each side wall which is one of the suggested positions by Harman and SVS. There are other suggested positions I'm going to try and I've already done a casual sub crawl. For one reason or another, perhaps the shape of my room, the Roon Room Simulator doesn't seem to give results that match the actual measurements so I'm no longer trying to use that. I don't want to spend a lot of time trying out and experimenting with different things only to post here and find out nothing I'm doing is useful. With that in mind, I'm starting with one sub centered on the right wall. I'm driving the subwoofers with the unbalanced outs on the preamp. I'm using the settings SVS suggested for my speakers (Wilson Audio Sasha ll's). They recommended a Low Pass Filter Frequency of 50 Hz and a Low Pass Filter Slope of 24 dB/octave.

I started out with this process by @Keith_W.

1. Set up the mic at the listening position.
2. Set up REW's generator to play pink noise from ALL the speakers.
3. Pull up REW's RTA view.
4. Adjust the phase of your subwoofer until the RTA is as flat as possible.

@staticV3 helped me with the settings for the Generator and RTA

The SVS subs can change Phase 1 degree at a time but I only tried 0 & 180. Again, because I want to make sure the process is right before I spend a lot of time on it. To me Phase 0 looked better so that's what I went with. The subs also have optional Auto EQ built into them. I tried both ways and the frequency response of the Auto EQ looked better to me than the non-EQ so that's what I went with.

Actually, now that I take another look at the graph of the Mains & Sub, with and without Auto EQ, maybe the dip of the Auto EQ is worse than the peak of without. In any case, I would appreciate it if someone could take a look at this and help get me pointed in the right direction. Thanks.

Hi, what do you think of this subwoofer? Is the bass too strong? Does it reproduce sound accurately? What other subwoofers have you compared it to? I’m thinking of buying a subwoofer soon—could you give me some advice?

 

[Daverich4]

Hi, what do you think of this subwoofer? Is the bass too strong? Does it reproduce sound accurately? What other subwoofers have you compared it to? I’m thinking of buying a subwoofer soon—could you give me some advice?

I have two of them. I’m setting them up to attempt to correct several room modes so have them turned down to where you’re not aware they’re actually on. I’ve had them turned up while experimenting and they will shake the windows and floor if that’s your thing. Don’t know how to answer your question about accurate sound because as I said, I can’t identify them as being on until I measure the sound or turn them off. I didn’t compare them to anything else, just did a bunch of reading and chose them that way. Here’s a link you might want to check out if you’re looking for expert advice on them.

https://www.avsforum.com/threads/official-svs-owners-support-thread.737143/