2 subs or not?

[geek_inside]

Hi everyone,

I’m looking for some advice on whether adding two subwoofers would provide a meaningful improvement in my listening experience as I've never dealt with subs.

Here's my current setup in my living room:

• Tannoy XT-8F floorstanding speakers
• miniDSP SHD Studio DSP/streamer (Dirac Live + custom REW PEQ)
• RME ADI-2 DAC FS used as DAC and preamp
• Audiophonics HPA-S450ET power amplifier
• Room dimensions are 4.4 × 6.6 × 2.7 m, with an opening on one side
• Usage: mainly music (≈80%) but also some movies (≈20%)

I’ve attached my room frequency response measurements taken at the main listening position (using MMM). The measurements shown are after Dirac correction and a small amount of additional PEQ generated with REW.

As you can see, there is, among other things, a significant room mode around 38 Hz and some irregularities around 85–100 Hz. I’ve already experimented with speaker placement as much as the room allows, and adding further acoustic treatment isn’t really an option since this is a shared living space.

If I decide to go the subwoofer route, I’m currently considering a pair of SVS SB-2000s (or possibly Arendal ones, as there aren’t that many good value options available in Switzerland). My initial idea would be to place one sub along the side wall and the second on the rear wall, with the goal of minimizing excitation of the dominant room mode as much as possible (particularly the ~38 Hz axial mode). I’m also open to alternative placement strategies if there are better approaches for modal smoothing.

The plan would be to integrate the subs with the existing Tannoys, but I’m still unsure whether the subs should handle the bass entirely or whether they should be blended with the mains. For integration, I was considering using a second DAC for the subs (e.g. SMSL SU-1), and switching to the SHD Studio as the main volume controller for the entire system.

I’ve never done sub integration before, so any feedback, suggestions, or criticism would be greatly appreciated.

Thanks!

 

[Redacted]

Two subs - twice the power! And it is argued that each one will be about half the volume of a single sub and in different positions, making room modes less prominent. People with speakers either side of a chimney breast are usually going to need a pair of subs.

For most people using affordable mains and subs, the XO point will be sufficient high that you will hear panning (eg of bass guitar) on certain recordings. Vinyl users are only getting bass in mono though. In your case, your mains go reasonably low (-6dB at 34Hz), but not quite low enough, IMHO, with bass guitar low E at ~43Hz. But that's about sub or no sub, not whether two are better....

Without a means for 'assisted room correction', be prepared for lots of work blending in any subs with the mains.

 

[WeekendWarrior]

Think you'd need a second DAC for the subs. The SHD Studio is digital only.

Or get subs that connect direct to your speakers, but then you wouldn't be able to set a high pass filter for the mains nor do other stuff you'd want to do.

 

[markstein]

When adding subs to your setup, you need either subs with digital input or a separate DAC. DSP (x-over, bass management, PEQ, all pass filters) can be managed with your miniDSP SHD Studio. Ideally you would use a miniDSP SHD for both, mains and subs, and use your RME for another setup. Or you add a four channel DAC to your miniDSP SHD Studio.

My personal experience is that two subs are better than one, and - so say Todd Welti and Earl Geddes - three to four subs are the optimum/ maximum required.
The Welti and the Geddes approach are very different in detail, you may search for papers or presentations available online to understand both. I personally never managed to add my two subwoofers in an acceptable way to my mains without x-over, so count me to the Welti camp.

Recently there was a lot of discussion on ASR regarding stereo bass vs mono bass and the perceived spaciousness of stereo bass. You may search for this topic and need to decide for yourself which route to go. A compromise could be to run your mono subs until 60Hz instead of the usually recommended 80Hz - you decide what sounds best to you.

A great help to understand the (at least rough) effects of sub placement on frequency response is the REW room simulation feature. You can play around with different placements without carrying your subs around and do lots of measurements. This is to get a first idea which placement makes sense and what would be the effect of additional subs.

Once there, you can use the software Multi Subwoofer Optimizer to figure out PEQ and all pass filter settings to get an as smooth frequency response across your listening area as possible.

This journey takes some time but can be a lot of fun

 

[Marc v E]

I have only experience adding 1 sub to genelec 8030. I use a crossover at 85hz and placed it close to the main monitors. Using them for music only, my experience is that it's definately worth it. Obviously more powerfull bass, but also clearer instruments and voices.

I haven't tried it with my 3 way mains yet, but expect I require at least 2 subs to notice an upgrade as they both have 10 inch woofers and reach 30 hz. Not sure what to expect in sound benefits. Probably a smoother response; possibly clearer mids/bass until 85 hz from the mains.

I would personally prefer to keep the number of devices needed for crossover and eq as low as possible, and if possible managed by 1 device.

 

[Redacted]

Luckily, most subs these days include amp, volume, and XO control implemented by internal DSP, so just just feed L & R subs with pre-outs L & R.

 

[Hayabusa]

yes!

 

[geek_inside]

Without a means for 'assisted room correction', be prepared for lots of work blending in any subs with the mains.

Do you mean it might be easier to let the subs alone deal with frequencies below the crossover (so without the mains) or do you mean sub integration is a lot of work in general? I read quite a lot about it and yes, it seems to be quite something. Planning to use REW for phase and rough level adjustements, then miniDSP console and Dirac for polishing. I have time to spend, and I'm willing to try.

Think you'd need a second DAC for the subs. The SHD Studio is digital only.

Or get subs that connect direct to your speakers, but then you wouldn't be able to set a high pass filter for the mains nor do other stuff you'd want to do.

As I said in my first post, if I buy the subs I'll probably buy a SMSL SU-1 for them.

When adding subs to your setup, you need either subs with digital input or a separate DAC. DSP (x-over, bass management, PEQ, all pass filters) can be managed with your miniDSP SHD Studio. Ideally you would use a miniDSP SHD for both, mains and subs, and use your RME for another setup. Or you add a four channel DAC to your miniDSP SHD Studio.

Yes, I already thought about it and I agree, it would be the easiest and cleanest way to do it. That also means selling my SHD Studio and buy the SHD :/

Luckily, most subs these days include amp, volume, and XO control implemented by internal DSP, so just just feed L & R subs with pre-outs L & R.

While I could do it with the RME DAC, I'd prefer to use the miniDSP console to set all parameters in one place. Plus I can't set a delay on the subs, but I can on the miniDSP console. Also, I currently use the RCAs outputs of the RME to feed my headphones amp. What I could also do in that case is using the SU-1 dac for the headphones amp, this will free up the RME RCAs for the subs (but again, loosing delay control).

 

[markstein]

Yes, I already thought about it and I agree, it would be the easiest and cleanest way to do it. That also means selling my SHD Studio and buy the SHD :/

I did it the other way - sold my SHD for a combination of RME ADI2-Pro FS R plus Fireface UFX II - and while the new setup is more performant in terms of SINAD, I should have simply kept the SHD if I am honest. The only really cool functionalities I would miss are 1) level meters on all I/Os, 2) loudness.

 

[geek_inside]

Yeah, loosing loudness will be tough. Thinking of creating a preset on the miniDSP console to emulate it, but of course it won't be dynamic.

 

[HalSF]

I’m a single-sub holdout, though there’s plenty of convincing objective evidence that properly calibrated dual subwoofer systems improve bass performance and tame various challenging room effects.

Partly it’s because the simpler, less expensive, less intrusive use of a good subwoofer on its own provides a palpable and intensely enjoyable benefit. Two may be better but one is not nothing!

Another factor is that two-sub proponents do a much better job of presenting the daunting technical complexity of integrating multiple subs than they do selling the results in a vivid, descriptive, and seductive way that makes it seem irresistible of worth the bother and $$$.

 

[Redacted]

Do you mean it might be easier to let the subs alone deal with frequencies below the crossover (so without the mains) or do you mean sub integration is a lot of work in general? I

I mean if you don't use REW, Dirac etc etc, you are down to playing bass test tones/sweeps (and well-known music tracks) and trying to assess volume, possibly by ear or with a phone (if you believe a phone can do it) and then adjusting the knobs for sub volume and cutoff to avoid shelves, humps or dips in freq. response.

 

[geek_inside]

I mean if you don't use REW, Dirac etc etc, you are down to playing bass test tones/sweeps (and well-known music tracks) and trying to assess volume, possibly by ear or with a phone (if you believe a phone can do it) and then adjusting the knobs for sub volume and cutoff to avoid shelves, humps or dips in freq. response.

I see, thanks for the explanation! That's not what I'm planning to do as I don't trust myself ). Joke aside, I'm already using REW and Dirac with great results so I will continue to do so.

 

[Redacted]

Another factor is that two-sub proponents do a much better job of presenting the daunting technical complexity of integrating multiple subs than they do selling the results in a vivid, descriptive, and seductive way that makes it seem irresistible of worth the bother and $$$.

Subjective in my case - i.e. there's nowhere to easily put a single sub anywhere my wife is happy with - we have a fireplace, so no point in a single sub on one side. I've tried - it sounds annoying. Plus, two lower-powered subs are not necessarily that more costly than one bigger/more powerful one

 

[Redacted]

I see, thanks for the explanation! That's not what I'm planning to do as I don't trust myself ). Joke aside, I'm already using REW and Dirac with great results so I will continue to do so.

It is entirely manually do-able*, if you have 3 spare days, and trust your own hearing to assess "good enough" over technical perfection.

*Ask me how I know.....

 

[rf1938]

Glad I added a second sub. Used Dirac ART to integrate, easy ( already familiar with ART). Using discrete sub outputs from AV10 even though the subs offer XLR daisy chaining. Definite improvement, but not overwhelming. If you can afford it, I’d do it. No regrets here. Mine are smallish - 16x16x18 roughly, dual 10” opposed drivers each, all behind a couch, so unseen.

 

[Mort]

I’m a single-sub holdout,

Same with Genelec GLM SAM subs, although I am adding a second sub soon to see if Dirac ART makes a difference.

 

[jsilvela]

I second what markstein says in this same thread https://www.audiosciencereview.com/forum/index.php?threads/2-subs-or-not.72041/post-2623935

I recently got a second sub after dithering for a long time.
I took inspiration from the Welti 2-sub configurations and then tested with Audyssey on my Denon and adjusted.
Used the REW simulator to get some insight with my room dimensions, was very helpful.

I've never managed to do the sub crawl, and I think/hope that with 2 subs it's less important.
My impression is 2 subs is less finicky than 1.

 

[Vive la dissonance!]

My impression is 2 subs is less finicky than 1.

It certainly felt that way to me!

 

[geek_inside]

For those with 2 subs, how did you deal with the integration? Did you set up the first one properly then add the second and readjust what was needed?