Adding a sub

Q Acoustics launched a nice subwoofer. Wonder what it would bring if I plug it into my SN2. Mostly I stream radio or Tidal, and I do whatch concerts and movies from time to time. Any stereo experience on a Naim system with a sub anyone?

I added the Cambridge Audio x301 Minx sub to my 252/300DR/805 D3. It gives an added weight and sense of space to some records, especially ‘thin’ productions. It’s really good for orchestral stuff. I’m still getting used to using the settings, but overall…win.

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@JanW I see the Concept 500s go down to 41 Hz and have a rear port so assume you’d be setting the sub at 40-45Hz which would blend in nicely and give you some extra bass on movies for sure. For stereo music listening, the effect is/should be more subtle such that at lower volumes the music is fuller and at any volume the bass not overpowering but somehow more present and well blended. Set up like that, and assuming your room and placement won’t create issues for you, it should be a good addition. But, if you are wanting to boost your bass to crazy levels beyond what was originally intended (by the artist/producer), I think this would interfere with the overall sound a lot and potentially have a detrimental overall effect. My personal experience was that care needs to be taken on the crossover and settings on the sub, to avoid bumps (my Kantas apparently go to 35 but I set the crossover at 40), so if the Q sub can be adjusted (my SVS has many adjustable features beyond just crossover) this will help you get it set up properly. For low volume listening, I nudge the sub volume up a DB or two, for louder listening, nudge it down.

Thanks, very useful information. Indeed I am not seeking for extreme bass levels, my speakers have enough power as they are. However I am surprised that you would recommend 40-45 Hz and not let’s say 35-41 Hz…is that purely because it would not blend but be more separated from the speakers? What about 35-45Hz ?
By the way, indeed the Concept 500’s have a rear bass port and have approx 60cm space from the wall. Room is spacious with enough free space to play around with speaker distance and placing.

In a way, yes, at that lower bass level I’ve found there is less risk of a bump but also because the sub is simply better at those lower frequencies, as this is what it is made to do. I don’t think this is the case for your speakers (or mine) but another reason to do so would be if the low frequency point published by the manufacturer was not actually as low as stated.

Also, I do sometimes set the crossover higher, to, say 50 (which is what SVS recommends for my speaker), but with some types of music I get a slight bump.

Ok thanks clear. So as long as you are able to simply adjust the settings in some case, you can enjoy the additional sub with all types of music.

I have recently added a couple of subs and would not be without them now. They add a lot to the experience, overall, and give some flexibility to optimise your system according to your room characteristics.


When I added a sub to my Nova/n-Sats system there were some unexpected benefits. As well as improved bass, all frequencies seemed to improve, but notably the sense of the space in which the music was recorded was transformed. I guess this must be due to almost sub sonic cues that are being dug out.
I wouldn’t be without mine - go for it!


There is a potential issue when adding a sub to any ported speakers; it affects some people but not others…

The issue is phase response and timing. The output from a bass port (reflex, open transmission line or ABR, it’s all the same) is 360° out of phase with the direct speaker output from the bass cone. If you then add a sub to a ported speaker, as you cross from the bass cone, through the port output to the sub, the phase goes 0° → +360° → 0°. For many people this will make the ‘timing’ of the system just sound ‘off’ in some odd way. (N.B. some listeners are completely unaffected by this timing/phase issue - you may fine with ported speakers and a sub).

If you don’t time align it by placing it closer to the listening position the timing of the crossover to the sub is even worse as then the phase goes 0° → +360° → ?, where the ? could be anything from about +20° to about +60° depending on the sub used and the settings. This part of the problem exists even for sealed speakers but in a simpler form ( the phase goes 0° → ?, without the +360° from the port output). While +20° may well be OK, at +30° or more, for many people the sound of the sub will be ‘detached’ from the rest of the sound from the system. (N.B. as above for the port issue, some listeners are completely unaffected affected by this timing/phase issue and can place a sub right by the main speaker without hearing this effect at all - you may fine without time aligning the sub).

I have used a single REL sub with a 250/SBL system and it was fine increasing the dynamics of the system and increasing ambience retrieval with orchestral music. Now I use a Velodyne sub with my 135s and again wouldn’t be without it. Both subs were connected to the speaker outputs of the power amps - essential for the system to work optimally imho. There are few subs out there that allow connecting a single sub to mono block amps like 135s - the Velodyne - now discontinued - was one. Also having a remote to adjust volume and phase from the listening position is a must for me.

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I’ve tried several subs over the years and I’ve never been able to obtain results that I was satisfied with. I found that one of two things always occurred - either the presence of the sub was obvious, ie. too much bass, or the sub was undetectable and made no difference. This after making extensive adjustments to crossover point, level, phase and positioning. The other thing I found is that if one managed to set things so that they sounded not too bad at a certain volume level, the moment the volume was changed the whole thing sounded wrong again - and yes the sub did have a variable volume feed!

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We played with a REL t7/x with my Falcons it was nice but perhaps a little to much of a heavyweight. This has now gone into the cinema room where it is producing excellent results. Not thump,thump but just adding to the soundstage in splendid way.
We await a REL t 5/x which it is hoped will work better with the Supernait and Falcons.
Jazz,a few vocals and chamber music is my choice so I hope it will provide like it’s big brother just gentle augmentation.

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I’m curious, why do you believe that?

High level connections cause several problems:

  1. The signal to the sub gets contaminated by the back EMF from the speakers bass cones
  2. You have the group delay (i.e. time delay) of the power amp to contend with as WELL as the group delay of the sub itself.
    3 you can’t separately filter the sub’s signal independent of the main speakers / power amp, so it make for more problems trying to integrate the sub into the room without degrading the midrange signal to the main speakers.

Problem 3 can often be handled by subs that have an internal DSP, but 1 and 2 are insurmountable.

On the other hand, a high level connection maintains the sound signature of the main amp as far as possible along the chain improving integration with regards to tonality and timing. REL always recommend that the high level connection is used with their subs for optimum performance.


OK, I can see how you may think that. Unfortunately in reality that doesn’t actually work:

In terms of timing, it’s bound to be worse as you have two time delays in series not just one from the sub.

In terms of retaining the sound signature of the power amp:
firstly that will be completely overridden by the Class D amp driving the sub
secondly even if it did retain part of the power amps signature, that would still be adding together two sets of aberrations instead of having just the one set, so again that just makes the situation worse not better!

When I had my hi-fi and home cinema system combined I added a Monitor Audio Silver Sub and it really improved the home cinema experience. However for music with my Wilson Benesch Square Ones and now Arcs, it always sounded as if the speaker sound was so much cleaner than the sub.

Now the systems are separate and the sub is staying with home cinema system. I have thought about a Wilson Benesch sub but it always works out cheaper to buy better speakers.

Try moving your speakers further from the walls and adding thick acoustic panels. You will be amazed how much extra bass appears from nowhere!


In reality, the subs sound great. Whilst you make some technical arguments that may suggest otherwise, I’ve not encountered any practical experience of their effect. Liked your comment about EMF! By the way do you mean ° → +180° → 0°, instead of ° → +360° → 0° in a recent comment above?

It’s about acoustic phase and not Electro Motive Force, so yes I mean 0° → +360° → 0°.

I don’t say that a sub connect via high level connections will sound bad, just that it will always be possible to make a better low level connection. (That is provided a low level connection is provided on the sub that is of at least similar quality to that of the provided high level connection - if the manufacturer has compromised too much on the quality of the low level connection then no it won’t sound as good!)

Ah! I’ve just realised the part about EMF was about the ‘Back EMF’ from the bass cones of the main speakers; sorry I misunderstand to what you were referring…
… yes they behave as generators as well as motors.

It’s really going to depend on how your mains roll off

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