2.1 system vs 2.0 system for Music

Huge posted:

I use one, half way down a wall, and the coverage is pretty even.

Good practice here. I advise anyone with a subwoofer to start by positioning a subwoofer half way along a wall.  Then try moving in steps one way or another.  And if you like it best back where you started in the middle then that's fine.

And yes, try to have the sub away from the speakers - on a side wall, or sometimes even behind you works best.

Funny you mention that Richard, my sub is right behind my listening position - that give the right difference in speaker to ear and sub to ear distances to compensate for the sub's group delay time (and this is confirmed by measurement with REW).

Incidentally the half-way along a wall principle is also supported by mathematical modelling.  I did the acoustic modelling to work out a few candidate positions before moving the sub around to experiment with the actual sound.  Mid point of the wall behind me gave the best sound and the best measurements, so confirming one of the the theoretical set-ups.

Incidentally I did the same mathematical modelling for the main speakers.  However, in this case, to get the optimal sound, I had to move them about 200mm and 150mm away from the positions that the model suggested.  Still not a bad way to start optimising the system though, getting it within 200mm is quite close using pure theory.

Chris, after a few years of trying to find the best way to set up the n-Sub, I settled on starting half way along a side wall and working in increments toward each corner and that way deciding on what worked best.  The problem, of course, is that rooms are all different and have glass and doors and furniture in all the wrong places, so it's often a case of the best possible position, rather than the ideal.

Thanks Richard, this thread is a timely reminder for me to revisit my N-Sub setup, having changed virtually my entire system since the last time I did it. I did consider trying some sort of DSP/room correction, but with a 282, I don't think a low level connection is possible, so it will have to be the trial and error method.

Huge posted:

Chris, how are you powering the 282?  If you're using a HiCap you can certainly do it.

I was dimly aware that this might be possible, but I seem to recall a comment on a previous thread (possibly it was Richard?) that this was not a good idea. Can't remember the details. 

I used dual subs (REL T7s) for quite a long time with various standmount speakers. Eventually sold them and bought floorstanders with good bass response and I'm much happier. 

Subs add stuff that regular speakers don't and I found that when things click it all sounds very good indeed, but all the tinkering, adjustments, experimenting with positioning etc. was becoming a chore and I decided enough was enough. I'd get it sounding good for a specific genre then listen to something else and be unsatisfied which lead to starting the whole tinkering process from scratch. 

If I were to use another sub now I would definitely invest in room correction like minidsp. 

If it's good for one genre and not others, then you've got a fundamental problem somewhere in the set-up, quite possibly location or a lack of adequate bass traps, causing uneven frequency response.  Dual subs can be very difficult to get right, particularly as people tend to think they'll sound best when placed beside the main speakers (they won't).

ChrisSU posted:
Huge posted:

Chris, how are you powering the 282?  If you're using a HiCap you can certainly do it.

I was dimly aware that this might be possible, but I seem to recall a comment on a previous thread (possibly it was Richard?) that this was not a good idea. Can't remember the details. 

The problem is connecting long interconnects cables to the extra output sockets on the HiCap and this putting too much capacitative load on the preamp output.
The trick is to use short interconnects from the HiCap to a DSP, and longer cable(s) from the DSP to the sub.

Chris, as Huge says above, it's an issue of capacitive load on the Hicap. You can slug with resistors - Naim do this with their own sub lead - but it can still affect overall performance. 

Im going to experiment with my own n-sub in the main system sometime fairly soon. Distance and layout probably precludes taking a high level signal off the speakers so it will have to at pre level. 

Richard if you use a DSP box (personally I use a miniDSP 2x4) and get someone like Flashback Sales* or Custom HiFi Cables* to make a very short DIN4 to RCA (say 0.3m), then place the DSP beside the HiCap, you'll only add about 40-70pF per channel (including connectors)

I don't think any of the current preamps should be significantly affected by this.

The miniDSP can then drive the long low level interconnect to the sub.

*  For a higher quality cable, you could also get a 1m AR Sound Lunar DIN4 to RCA (that will still only add about 80pF including connectors), and Ari may be prepared to make a shorter one for you (a 0.5m cable would add about 50pF).  Of course you could always make your own cable!

Regarding high-level connections, another option is to use a Jensen Transformers Iso-Max SP-2SX 2-channel speaker level to (balanced) line level converter.

I use one with a DSpeaker 2 channel room correction box and dual REL Storm IIIs running in stereo.

To connect it, I made custom cables with spades from each speaker, to the SP-2SX speakon input connectors. Then the SP-2SX balanced line level outputs are connected to the balanced inputs of my DSpeaker Anti-Mode 2.0 using standard balanced XLR cables. And then a second pair of balanced XLR cables are connected from the DSpeaker balanced outputs to the "BAL LO" inputs on each of the Storm IIIs. So the extra processing is only applied to the less critical subwoofer signal. Works for me.

Alternatively, the SP-2SX also has a terminal strip that accepts bare, tinned or pin style connections for all the inputs and outputs.

FWIW, excerpts from published specs/claims for the SP-2SX...
• Delivers exceptionally low distortion down to 20 Hz
• Ruler flat frequency response from 5 Hz to 20 kHz
• Once connected, the SP-2SX is able to withstand signal levels to +19 dBu at
20 Hz without introducing distortion, phase shift or artifact of any kind.

Regarding single vs dual subwoofers, I happen to like the even greater expansion of sound stage that I get with dual subwoofers in stereo, but of course you could alternatively run both SP-2SX output channels to a single subwoofer.

Huge posted:
ChrisSU posted:
Huge posted:

Chris, how are you powering the 282?  If you're using a HiCap you can certainly do it.

I was dimly aware that this might be possible, but I seem to recall a comment on a previous thread (possibly it was Richard?) that this was not a good idea. Can't remember the details. 

The problem is connecting long interconnects cables to the extra output sockets on the HiCap and this putting too much capacitative load on the preamp output.
The trick is to use short interconnects from the HiCap to a DSP, and longer cable(s) from the DSP to the sub.

I've recently been experimenting with a (cuddly) hicap, so I might give it a try. I'm thinking of moving the system to a different room, which has a suspended floor and limited flexibility for placement options, so I'll need all the help I can get with room acoustics. 

OK, I see that my subtle hint has been ignored, so please could members ensure that they respect forum rules - in particular with regard to refraining from discussion of unauthorised modifications to Naim equipment, which includes non-Naim power supplies on pre-amps, CD players etc..

Huge posted:

Yes, subs can be critical of position.  I did like the idea someone had of hanging one from the ceiling!   

So i decided to play around on the weekend, i tried every position i could except behind me (don't have long enough cables for that). I could not hear the subs at all anywhere along the side walls unless i stood directly opposite the subs. So far, they sound best up front beside each of my speakers. I am going to have to get some wire and try behind me at some point. 

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