Adding subs to a nearfield desktop system

[davybyrne]

Looking for input on sub selection and integration for a nearfield desktop setup. I currently have a pair of REL Tzero MkIIIs with 30 days left on the return window and I'm increasingly convinced they're the wrong call for this application. Before I pull the trigger on replacements, I'd appreciate a sanity check. For purchasing options, I'm in the US though not near a major city.

I listen to a broad range of music, from classical, opera, and jazz to rock, prog rock, and electronic, including edm.

Current setup:
- Source: Qobuz or Apple Music on Mac Studio (M2 Ultra)
- DAC/interface: MOTU M2
- DSP: miniDSP 2x4HD (handling crossover, PEQ, sub integration)
- Amp: 3e audio A7
- Mains: KEF Q1 Meta (nearfield, ~3 ft listening distance on Kanto SP9 stands with tweeters at ear level and toed in)
- Subs: currently 2x REL Tzero MkIII using RCA from miniDSP (returnable)
- Measurement: UMIK-1 + REW. Current best SPL/Phase measurement below

Room (photos below): third-floor home office, roughly 11ft (3.3m) x 32ft (9.7m), carpeted with wood-paneled walls angled to 8.5ft (2.5m) ceiling. Subs currently sit in unused floor space flanking the desk, though I understand symmetric placement isn't necessarily optimal for modal smoothing and I'm open to measuring alternatives.

What I'm considering:
- Pair of Rythmik L12 (sealed, servo) — which seems like the better buy for modal smoothing than one bigger sub
- Pair of SVS SB-1000 Pro (sealed)
- Very open to recommendations up to ~$1,500 total cost

Along the way I have tried a few other individual subs (the REL Tzero MkIIIs are the only pair I've tried): KEF Kube 8 MIE, KEF KC62, SVS 3000 Micro. I should also mention that my previous setup was a pair of JBL 305P Mk IIs with a single JBL LSR310S sub. So far, subjectively the best sounding to me has been the Q1 Metas with the pair of REL Tzero MkIIIs. For the money ($1,100 for the pair), I'm just not convinced the RELs are a good value and I don't care about glossy black or the tiny footprint.

Questions:

1. Any reason to prefer the SB-1000 Pro pair over the L12 pair at roughly comparable cost, specifically for nearfield music use with upstream DSP already handling integration?

2. Am I right to dismiss the REL Tzero MkIII as overpriced for its measured performance, or is there something I'm missing beyond the cosmetics and high-level input marketing (again, I'm _not_ using the high level inputs)?

3. For nearfield (~3 ft), is there any practical downside to dual subs vs. a single better sub, given that I've got miniDSP to handle delay/level/PEQ per sub?

Thanks in advance.

 

[Chrispy]

I don't find any Rel sub worthwhile myself, all overpriced and underperforming....particularly those tiny Zeros, they really aren't true subs in any case.

I'd stick to duals generally, but for a single seat a single sub can work well enough. I wouldn't necessarily consider sealed but if size restraints, understandable. Not a huge Rythmik fan, but if same cost as SVS, wouldn't expect huge differences. How are you implementing a crossover with that amp?

 

[davybyrne]

I don't find any Rel sub worthwhile myself, all overpriced and underperforming....particularly those tiny Zeros, they really aren't true subs in any case.

I'd stick to duals generally, but for a single seat a single sub can work well enough. I wouldn't necessarily consider sealed but if size restraints, understandable. Not a huge Rythmik fan, but if same cost as SVS, wouldn't expect huge differences. How are you implementing a crossover with that amp?

I'm using a minDSP 2x4HD for crossover and room correction. Two of the miniDSP's four outputs go to the 3e audio A7, the other two go to the subs.

 

[Chrispy]

I'm using a minDSP 2x4HD for crossover and room correction. Two of the miniDSP's four outputs go to the 3e audio A7, the other two go to the subs.

So just a single source connected directly to the 2x4?

 

[nOOky]

After a lot of searching I went with a single SVS SB3000R over two smaller subs and for my room it's probably overkill, but I'd prefer that lower extension and room filling pressure of the 3000. I'd buy one of those and add another later if I found it lacking

 

[davybyrne]

So just a single source connected directly to the 2x4?

Yes. Mac Studio -> Motu M2 -> miniDSP -> 3e audio A7 and subs.

 

[davybyrne]

After a lot of searching I went with a single SVS SB3000R over two smaller subs and for my room it's probably overkill, but I'd prefer that lower extension and room filling pressure of the 3000. I'd buy one of those and add another later if I found it lacking

I think part of what I'm trying to figure out is how to rationalize some of the advice and experiences I've read about in other threads. I've seen some where people say "dual subs are better than a single for imaging." I've seen others where people say dual (or more) subs are better because strategic placement can fix room modes. I hear you saying that a single sub gives you the extension and SPL you're looking for.

I think for my nearfield setup, the imaging is better with the pair of subs. More extension would be nice since the Tzeros are basically glorified 6.5" woofers. I'm pretty sure I don't need SPL. I'm also expecting someone to chime in about room treatment, which is another whole can of worms.

 

[levimax]

My advice will probably be different than others, but I do have 6 subs and have played around with them quite a bit so take it as experienced random internet advice :

1. Since you have DSP I would avoid subs that also have DSP. You will find the added latency and other DSP features will be fighting against you the whole time and the mini DSP is far better than any "helpful DSP" built into a sub.

2. I would study the test done with 10 popular sub by a member of this community. https://www.audiosciencereview.com/forum/index.php?threads/i-measured-10-subwoofers.49042/ The measurements are comprehensive and go far beyond just "LF extension per dollar". I would avoid high group delay and note how high distortion is on many of these popular subs (the CEA-2010 standards used are very lax). Time domain issues are both audible and affect integration so I would also look at the step responses, many of these small subs ring like bells. I think the L-12 is OK but not tested here, the big Adrinal sub is the best of this group.

3. Especially for nearfield use but also for future far field use of multiple subs I would get one "good sub" (low group delay, low distortion, high SPL) rather than 2 lesser subs. Despite what you may read if you have a powerful enough sub that has the headroom and low distortion you can "fill in dips" with DSP (Only if the dips respond linearly to added boost and only ~ 6 dB maximum). I have found I can get just as smooth FR with fewer "good sub(s)" than multiple "poor" subs. The good subs will also have lower distortion and higher SPL and better time domain behavior which will sound better.

4. There are better choices than REL.

Good luck and have fun.

 

[Chrispy]

What is imaging with subs? Multiple subs are largely about smoothing room response (throughout the room), plus some overhead advantages. If just one seat then a single sub can suffice with good placement/setup, but might be easier with duals.

 

[nOOky]

I think part of what I'm trying to figure out is how to rationalize some of the advice and experiences I've read about in other threads. I've seen some where people say "dual subs are better than a single for imaging." I've seen others where people say dual (or more) subs are better because strategic placement can fix room modes. I hear you saying that a single sub gives you the extension and SPL you're looking for.

I think for my nearfield setup, the imaging is better with the pair of subs. More extension would be nice since the Tzeros are basically glorified 6.5" woofers. I'm pretty sure I don't need SPL. I'm also expecting someone to chime in about room treatment, which is another whole can of worms.

If you were talking about a home theater where you are well back from the front and center speakers I personally think stereo subs may allow better imaging, especially if they are crossed over rather high, as well as other advantages. But from your pictures I'd likely plop that sucker right by my feet under the desk as the near field stereo speakers are right in your face. What would you cross the sub over at? I'm not sure how low those speakers you have reasonably go.

 

[davybyrne]

What is imaging with subs? Multiple subs are largely about smoothing room response (throughout the room), plus some overhead advantages. If just one seat then a single sub can suffice with good placement/setup, but might be easier with duals.

Yeah, I totally get where you're coming from. In my case, I've found that to address a dip between 80 and 100Hz I needed to crossover between 100 and 120Hz, which starts to make the sub positioning noticeable. This is my first time trying to do room correction, so I'm sure I'm making lots of mistakes.

 

[Chrispy]

Yeah, I totally get where you're coming from. In my case, I've found that to address a dip between 80 and 100Hz I needed to crossover between 100 and 120Hz, which starts to make the sub positioning noticeable. This is my first time trying to do room correction, so I'm sure I'm making lots of mistakes.

Multiple subs can help avoid localization with higher crossovers. Sub positioning is the first step, tho.

 

[davybyrne]

If you were talking about a home theater where you are well back from the front and center speakers I personally think stereo subs may allow better imaging, especially if they are crossed over rather high, as well as other advantages. But from your pictures I'd likely plop that sucker right by my feet under the desk as the near field stereo speakers are right in your face. What would you cross the sub over at? I'm not sure how low those speakers you have reasonably go.

I've seen various recommendations, most say to cross over at 80Hz. I'm testing between 100 and 120Hz to try to smooth out the response between 80-100Hz (farily successfully as you can see in the graph I posted).

 

[davybyrne]

2. I would study the test done with 10 popular sub by a member of this community. https://www.audiosciencereview.com/forum/index.php?threads/i-measured-10-subwoofers.49042/ The measurements are comprehensive and go far beyond just "LF extension per dollar". I would avoid high group delay and note how high distortion is on many of these popular subs (the CEA-2010 standards used are very lax). Time domain issues are both audible and affect integration so I would also look at the step responses, many of these small subs ring like bells. I think the L-12 is OK but not tested here, the big Adrinal sub is the best of this group.

I did come across that thread and found it both very interesting and completely overwhelming to try and sift through.

 

[Chrispy]

I've seen various recommendations, most say to cross over at 80Hz. I'm testing between 100 and 120Hz to try to smooth out the response between 80-100Hz (farily successfully as you can see in the graph I posted).

The general recommendation of 80hz is based on general localization experience with a single sub afaik. I've found with multiple subs that it is not as important at all.

 

[LTig]

I use a single Neumann KH750DSP for 2 Genelec 8020a, using the crossover in the sub. The sub is fed via SPDIF and sits under the desk close to my feet (the only possible location). Sound is fine without Room EQ.

 

[witwald]

I use a single Neumann KH750DSP for 2 Genelec 8020a, using the crossover in the sub. The sub is fed via SPDIF and sits under the desk close to my feet (the only possible location). Sound is fine without Room EQ.

The Neumann KH750DSP 10-inch subwoofer has very good measured performance. Little wonder that the sound is fine. Compared to a pair of REL Tzero MKIII 6.5-inch subwoofers, the OP would see a very big upgrade in performance if switching to using even a single KH750DSP subwoofer.

The 10-inch driver in the KH750DSP has 2.4x the radiating area of the 6.5-inch driver in the TZero MKIII, and it could also be expected to have a large XMAX. In its specifications, the KH750DSP has an F3 = 18 Hz, versus an anticipated F3 = 48 Hz of the Tzero MKIII (indirectly specified by F6 = 37 Hz); that's well over an octave more bass extension! In addition, the KH750DSP shows a textbook step response performance, and it clearly outperforms many other subwoofers on this particular metric. This implies that the overall transient response of the KH750DSP is of a very high standard and is not unduly affected by any internal signal processing choices.

The frequency response and step response plots shown below were taken from https://www.audiosciencereview.com/forum/index.php?threads/i-measured-10-subwoofers.49042/. Here the measured roll-off rate on the KH750DSP is about 17 dB/octave, which is approximately one order higher than the natural 2nd-order roll-off in a sealed enclosure.

 

[davybyrne]

Compared to the REL Tzero MKIII 6.5-inch subwoofer, the OP would see a very big upgrade in performance if switching to a even single KH750DSP.

For triple the price I'd sure hope so!

 

[Mike_Trueman]

Did you buy the SVS 3000 and are you happy with it?
I almost have the same nearfield setup as you but i use only one 12" subwoofer (SVS SB-1000 Pro), if you do not use a high-pass filter higher then 80hz then i see no point of 2 subwoofers in smaller rooms.

 

[witwald]

For triple the price I'd sure hope so!

If one is using 2x REL Tzero MkIII subwoofers in their setup, then the cost of one KH750DSP is only 2549/(2*949) = 1.34 times higher (34%), not triple the price.