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Need help uprading from 7.1.4 to 7.2.4

WinWiz

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Hello.
I'm seeking advice regarding my plan to include a second subwoofer. So please guide me in the right direction.

I don't have a room dedicated to ht, so practical compromises have to be made.
Our house is centered around a "L shaped" room with kitchen and living room in opposite ends.
20220414_175407.jpg


Current setup:
I'm generally pleased with my current 7.1.4 setup -but the low frequency response varies a lot between my two listening positions.
I believe a second subwoofer could help "smoothing out" the low end.
My current setup consists of dynaudio dm 3/7 front speakers, dynaudio sub500, dm center, dm 2/6 rear speakers, dayton me525mtm in wall side speakers and micca m-6c ceiling speakers.

What sub?
My hifi budget is limited. So what affordable sub would I need to accompany my (sealed [email protected]) dynaudio sub500?
Prime candidates are monolith 10" thx, svs sb/pb 1000 or xtz sub 10.17 edge.
A ported sub would probably be beneficial in my largish room, but I generally prefer the sound from sealed subs. I'm also wondering if a sealed sub would match my existing sub better than a ported sub?
I can purchase a glossy white svs sb1000 locally for 538€. Which seems cheap for a decent 12" sub. The small size and glossy white color definitely increase the waf (happy wife = happy life)
But it does seem lightweight compared to some of the slightly more expensive options.
I generally listen at -18db (max) +6db low-end boost and outside null modes my current 250w sub seems to keep up just fine. So I don't believe a second sub would need 500+ watts to acompliment my current sub...

Sub placement:
Only practical place for a second sub would be in the small "corner" below my wall mounted left rear speaker. For aesthetic/practical reasons this placement would require a wireless connection. I know svs makes wireless dongles. I'm sure wireless would introduce some delay. I believe my denon x3700h (audyssey xt32) should counter this delay. But nomal wifi delay varies so I wonder if the delay introduced with the svs dongle is constant?
If wireless options are crappy and/or expensive I could run a rca wire inside wall/ceiling but that would be a long distance and I fear existing 230v cables could introduce 50hz noise. It would also be a major hassle.

I would like to simulate the frequency response but I don't know any software for L shaped rooms...
I do have a umik-1 mic so I guess I could move my existing sub500 in the location where a second sub would be placed. But my sub500 is heavy and I don't have such a long rca cable.

Please let me know if my planned upgrade is flawed or if I'm missing something.
 

amicusterrae

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You have a "difficult" room for optimizing bass, but you aren't alone!

Absent advanced signal processing, adding another sub is not going to smooth your response between the two listening positions unless: both subs are identical, driven with identical signals, and located in opposite polarity positions of the troublesome room width and/or length mode(s). I am not knowledgeable about xt32's capabilities, and maybe it does the more advanced sound field management you would need to smooth bass response across multiple seats.

If you match the subs, you can still get improvement manually. Just looking at the shape and size of your room, the two locations you've identified look promising, but it's trial and error. Years ago I used to model a challenging L shaped room. It might do what you are looking for, but it's not cheap. Since you have a good mic, you can experiment with different locations--if you want to invest the time.

I have the SB-1000 pro, and it's a nice little sealed sub. The built in, app controlled parametric EQ is a great feature, but that only helps one listening seat. It's best attribute is probably it's size and weight. It blends into my family room really well and can be moved around with ease. And it adds just enough low end for my two channel system in that room. In my rectangular theater room, I use two SB-2000s located symmetrically close to the side wall midpoints, and the output is so much more satisfying.
 
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WinWiz

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Are you saying purchasing a second sub wouldn't help if it isn't identical to my existing sub?
My sub500 is almost 15 years and was discontinued by dynaudio many years ago. I really like this sub but only purchased it because I got it at 70% discount.
So getting another sub500 is not an option.
I only have 2 possible placements for subs in my living rooms: Where my sub is currently placed or bellow my left rear surround speaker. So not much to experiment with. A very slim sub beneath my couch could also be possible -but height would be limited to 12cm.
This is audysseys sub measurement from one side of my couch:
Screenshot_20220414-220238_MultEQ.jpg


And from the other side of couch:
Screenshot_20220414-220315_MultEQ.jpg

So the difference is pretty extreme...
 

amicusterrae

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Yes, the "manual" method of smoothing bass response across multiple seats depends on using identical subs in specific locations. This presentation covers the basics: https://www.harman.com/documents/multsubs_0.pdf. There's other more accessible stuff out there.

With advanced signal processing, it is possible to smooth response across multiple listening areas with mismatched subs and more flexible locations. Again, I don't think xt32 does that, but others might be able to address that.

Are those measurements before EQ? I like the position with the peak better because cutting that should be an easy fix for Audyssey. At the other position, it will want to fill in the valley, which is counterproductive. Also, the high pass roll off looks a little steep to me at both spots, FWIW.
 
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WinWiz

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Yes both measurements was before eq. The peaky position is right side of couch -where my wife useually sits. So if audyssey cuts the peak, bass in my listening position really suffers.
Next time I'm alone at home I will try turning the sub +/- 90° and measure the frequency response.
And you are right the low pass filter looks very steep. I'm sure I turned the subs low pass off, but my sub500 seems to forget it's settings when power is unplugged. So I will have to check if both avr and sub employ a 2nd order filter -effectively creating a 4th order filter.
 
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WinWiz

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I just skimmed the linked Harman doc and it doesn't say that subs should be identical. But it does state that results only apply to rectangular rooms...
 
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WinWiz

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Yes, the "manual" method of smoothing bass response across multiple seats depends on using identical subs in specific locations. This presentation covers the basics: https://www.harman.com/documents/multsubs_0.pdf. There's other more accessible stuff out there.

With advanced signal processing, it is possible to smooth response across multiple listening areas with mismatched subs and more flexible locations. Again, I don't think xt32 does that, but others might be able to address that
Do you have source for this? I just googled it and it seems lots of folks use unmatched subs successfully. Naturally weakest sub will limit the output but it's possible to counter this by placing the weak sub closer to the listening position. I also read that mixing ported and sealed subs is problematic because of phase shift at tunning frequency in ported subs.
 
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Sancus

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The problem with different subs is you'll be limited by the output of the weaker one, as you said. If you're fine with that, then it's OK. Yes, there are ways around this -- but it's adding complexity to a problem(bass smoothing) that is already very complex, and when subs are cheap as dirt as they are nowadays, it really just doesn't make any sense to me.

That said, it's your system so do what you want. For any multi-sub system I strongly recommend getting a miniDSP and learning to use Multi-Sub Optimizer -- it produces much better results than anything I know of short of room correction systems that cost many thousands.(Dirac Bass Control). It did very well for me in an exceptionally difficult room with only two subs.
 

FrantzM

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Hi

Using multiple subwoofers is IMO and IME , the ultimate solution for best bass in a room. Notice that I said, "in a room". Multiple subwoofers will , in most cases afford you good and uniform bass response ins several seating positions within the room. It does take (lot of :()work and knowledge but it works, very well and dare I say, surprisingly well. The subwoofer needs not be identical, by the way. Absolutely not. Best to stay within the same technology of subwoofers, for example. sealed all the way or ported ... even that is not cast in stone as you will get good results with a mixture of subwoofers, within their limits of course
What is your budget? Let me suppose , that it would be the same as the Dynaudio SUB500... or less. Quick search on Google $1900.oo. I believe you can do better for less. Don't go for Rel or Dynaudio.
Keep the system as it is. Add to it, a miniDSp 2x4 HD. About $300.oo or if budget is tight, you can get the miniDSP 2x4... about $150. This will be the DSP for your subwoofers. Acquire another subwoofer, @sweetchaos Subwoofer Comparison should be your guide. If you are in the USA, for a budget of $1000.oo or even less, there are many options, some I would deem better than the Dynaudio SUB-500. SVS comes to my mind almost automatically and the SB-3000 at $1099.oo is as good as they get and IMO, better by all objective metrics than the Dynaudio 500.... even its smaller brother, the SB2000 Pro at $899 is better than the Dyn-500, any od f the SVS would become then the mains subwoofer. Move it to the right front corner of the room. Leave it there. No subwoofer crawl necessary. It will be reinforced by the boundaries for better output...

Download REW and MSO and prepare yourself for some work , measuring, learning and measuring again. MSO is not easy IMO but you can get the hang of it after a few days... The second subwoofer can be placed in the back of the room. Just place it where it is most convenient. Your constraint is that you have just one position left for a subwoofer. Place it there. Not a flippant recommendation, Just - place - it - there.

Then measure the two following the recommmendation from MSO. Optimize the response for the subwoofers. Do not include the mains in this process. Ignore them; then make sure your subwoofers are as linear as possible, using MSO. This will take time, believe it. First to understand MSO, second, MSO takes some time to calculate the parameters and, kind of audiophile porn, you see the resulting curves :) getting better...
Now you introduce MSO parameters with your subs in place (front right corner and under one of the surround) in the miniDSp 2x4. The resulting subwoofer (2 subwoofers + the miniDSp 2x4) is to be presented to Audyssey as just one subwoofer. Let Audyssey do its things, correct its subwoofer reference curve, people here will help you in that. Let Audyssey, integrate the mains, surround and Atmos with what it sees as one subwoofer. You may be, I could go out on a limb and say , you will be pleased by the results. MSO + miniDSP is as powerful and cost-effective as it gets. Not easy to learn, but worth the results , it is set and forget and enjoy. Bass you didn't think your system capable of... (after hours of working and learning and researching and ... sweating :)). Also turn on Audyssey Dynamic EQ, the results are IMO , most satisfying, since most people don't always listen at, what is referred as "Reference" levels, nor would it be recommended to do so...

Long post. let us know what you think and have done.

REW, MSO and miniDSP rule!!! :D

Peace.
 

FrantzM

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The problem with different subs is you'll be limited by the output of the weaker one, as you said. If you're fine with that, then it's OK. Yes, there are ways around this -- but it's adding complexity to a problem(bass smoothing) that is already very complex, and when subs are cheap as dirt as they are nowadays, it really just doesn't make any sense to me.

That said, it's your system so do what you want. For any multi-sub system I strongly recommend getting a miniDSP and learning to use Multi-Sub Optimizer -- it produces much better results than anything I know of short of room correction systems that cost many thousands.(Dirac Bass Control). It did very well for me in an exceptionally difficult room with only two subs.
+1

Didn't see this post while posting mine.
 
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WinWiz

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I got the dynaudio sub 500 very cheap because I worked for dynaudio. I would never pay that much for a sub!
I live in Denmark (EU) so available brands are limited. And import tax makes importing from uk/us expensive.
If weakest sub will set the limit anything better than my sub500 wouldn't be utilized fully. -But I do like value for money and headroom for bass :)
I have some experience with car hifi, so I do know how to use rew.
Putins war have cause high inflation so my sub budget is limited to 600€. (And 500€ would be better). I am not going to invest in a mini dsp. Audyssey and ratbuddyssey will have to do.
I looked at some photos showing the svs sb1000 internals. Thin cabinet with zero reinforcement, rather disappointing.
Monoprice subs seems great value. But only ported versions available in EU.
Some brands like monoprice and xtz offer port plugs. I kind of like this because it would allow me to test both ported and sealed. I have made a few diy (passive) subs for cars and understand that some drivers are better suited for sealed subs while others (low qts) works better vented. Does modern dsp change this?
Anyway I think I will spend 500€ on a used svs sb2000.
 
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WinWiz

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The problem with different subs is you'll be limited by the output of the weaker one, as you said. If you're fine with that, then it's OK. Yes, there are ways around this -- but it's adding complexity to a problem(bass smoothing) that is already very complex, and when subs are cheap as dirt as they are nowadays, it really just doesn't make any sense to me.
Subs cheap as dirt? I think your dirt might cost a little more than my dirt...
Please guide me towards a sealed sub available in EU capable of [email protected] 2m/rms for less than 600€..?
 

Sancus

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Subs cheap as dirt? I think your dirt might cost a little more than my dirt...
Please guide me towards a sealed sub available in EU capable of [email protected] 2m/rms for less than 600€..?
I don't know much about the EU market, and researching it from North America is too much of a pain(geoIP & language), sorry. But I generally consider anything under $1K to be really cheap. If unusually high output is a priority, then ported subs will be much more cost effective. You can't beat the Monoprice ported stuff, it's absurdly cost effective.

Two subs each with 105dB capability as measured in half space will do 117dB placed against walls together, which is quite loud. If I was in Europe I'd probably buy the Arendal 1961 1S but they're not really super-budget subs. They are great quality though. I suggest the Subwoofer Comparison spreadsheet for doing your own research.
 
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WinWiz

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Yes the arendals build- and sound-quality seems high. If I was a single with money surplus that's what I would get.
But I can't justify spending that much on anything that's unnecessarily. So after looking at the sub comparison sheet I did what I useually do, when in doubt about what hifi to purchase: Go for the best price/weight ratio.
So a monolith 10" thx should be on it way :) I was about to order the ltz 12" because 12" 700w ice power amp and 4 port configuratios for same price as the monolith 10" seems great. But no cea measurements +buy and try not including return shipping sealed the deal in favor of monoprice.
The monolith 12" seems to share a lot of things with the monolith 10" so @ 1000€ vs 600€, for about 5db more output, seems a little steep...
With Free shipping including returns I can return the 10" if I find it to small for my largish room. But I doubt I will.

I'm wondering why xtz doesn't change the marketing strategy. If they provided cea measurements and free returns I'm sure they could sell a lot of subs in the eu market. Unless of course their measurements are bad...
 

amicusterrae

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Do you have source for this? I just googled it and it seems lots of folks use unmatched subs successfully. Naturally weakest sub will limit the output but it's possible to counter this by placing the weak sub closer to the listening position. I also read that mixing ported and sealed subs is problematic because of phase shift at tunning frequency in ported subs.
Floyd E. Toole, Sound Reproduction, Ch. 8 (3d Ed. 2018)
 
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