Naim XS2 and REL T Zero - guidance for best setup?


I’m a happy owner of a XS2 paired with a couple of Spendor SA1 (newest).
In order to add to “meat” on the bass (jazz) I’ve bought a REL T Zero (size & WAF matter).
REL is recommanding high level connection on the speakers plug but the XS2 has dedicated RCA outputs for subwoofer.
What is you reco on this setup ?
Additional one, the REL has only 1 RCA for low level and not R+L.
I’ve read that low frequencies are mono so R or L doesn’t matter.
Any confirmation / advice.

Thanks proud Naim’s owners :wink:

Hi Thierry
The easy way to connect the sub is with a single (mono) RCA cable from one of the Nait sub out sockets. As you say, low bass is almost mono so this compromise may not be too bad. Still, the high level connection is likely to sound better.
If you use the high level lead that Rel supply you can connect it to the speaker output terminals as explained in the Rel manual. It will work fine, but Naim recommend that you connect to the input sockets on your loudspeakers instead as this is best for the power amp performance. To do this you need to split the Rel cable to run it to the two speakers (or buy a specially made split cable). Whatever you choose to do you will need to give careful consideration to your choice of plugs as they will have to join the main speaker cable and sub cable into a single socket.

Another consideration is that the easier low level connection may be OK, but very long cables are not ideal, so the distance between amp and sub may influence your decision. Longer high level cables are not a problem.

Hi ChrisSU,

Thanks for your reply it is very clear and helps undersanding the connection types.
I’ll start with the low level and short lenght (2.5m).
Using the recommanded Naim setup will be a bit messy visually in my configuration.
Enjoy your weekend.

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I’m using the same sub with a pair of ATC SCM11’s & have tried both of the connections, connected to the speakers gave the best results. But there’s just Mae (GSD) & I - no ‘partner’ to say “too messy” :grinning_face_with_smiling_eyes:
The cables are very slim & can be hidden quite well (still got to do that :grimacing:), but well worth using that connection. Positioning/set up will take some time, but will ‘pay dividends’, it surprised me how little the volume/frequency needed to be set - very easy to ‘whack them up’ & it sounds well ‘over the top’.
Spend some time with set up, & then enjoy.

Follow REL’s setup instructions. That’ll get you 85% of the way. Pay particular attention to setting the phase correctly, and placement. Read the manual twice👍


Thanks JR007, really appreciated !
I think I’ll try both setu to figure out the best to me.
Good WE !

:+1: :+1: :+1:

My best results with REL subs and Naim are to use their high level connection to the speakers. Better low end than when I tried the low level sub out on a Supernait 2. The amp is not aware of the subs when hooked into the speakers. I have a pair of subs which makes set up easier than one though.

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Thanks dknk,

When connecting the high level speakon to the speaker terminal, how do you setup the cables ?
Do you join RED+YELLOW to positive and black to negative on ONLY ONE speaker?
Do you use RED to one speaker terminal on positive and YELLOW on the second speaker while splitting the black on both ?
Thanks for your insights.

Just one black - (negative) on one speaker, as it’s ‘common’, red to right + & yellow to left +

:+1: Thanks, I’ll give a try.

By the way any suggestion for the size (diameter) of the cables?
I’m going do build it and it should be less than 4m long.

Any cheap, thin speaker cable will be fine, there is no benefit to using anything expensive. Your main speaker cables are more important.

First, and importantly, get an instrumentation mike such as a miniDSP UMIK-? (1 or 2) and a copy of REW so you can align the crossover correctly (amplitude frequency and timing).

Best connection method by far: get a miniDSP 2x4.
Connect the inputs to the RCA outputs of the XS2 and connect one output cable to the low level input of the sub.
Use REW to setup the miniDSP to do the crossover to the sub:

  1. Sub level setting: you’re looking for a reasonably even frequency response through the crossover region with possibly a small rise into the deep bass.
  2. Sub positioning phasing and & delay: do not invert the phase, move the position of the sub closer to the listener until the minimum phase plot shows a smooth transition through the crossover region.
  3. Set the miniDSP to combine both input channels into the output channel (i.e. mono out operation).
  4. Room correction: apply parametric cut filters to reduce the sub’s output in places where it is excessively enhanced by the room resonances.

Good, thanks a lot, I’m ready for the next steps now.
Thanks all for your support and great advices.

Thanks Xanthe,

It opens a lot of possibilities.
I was looking at REW for a while and it may be the right opportunity to jump in.
1000 thanks to all, it’s really great to have such support.

There can be an element of luck in setting up a sub. It certainly pays to try different positions around the room, and there are different opinions on how best to position a sub, but in some rooms it just seems to work really well, whereas in others it never seems to sound quite right. In this case using DSP as Xanthe suggests would be well worth a try.
Another option if you use a streaming source is to use Roon and load the results of room measurements into its digital eq software, but that won’t work if you use analogue sources.

The usual mistakes are to put the sub in a corner of the room or beside the main speakers.

The first of these causes the room modes to be exaggerated.
The second prevents proper time synchronisation between the sun and the bass driver of the main speakers.

REW allows you to clearly see the problems resulting from these errors.

Of course you could try setting it up as REL suggests. They may know a thing or two about their products. Or as Xanax suggested you can spend more money on the mic :microphone: and mini Dsp than the £349. that the sub costs.

The do, and for both home theatre and 2 channel use, they advise setting it up as an acoustic effects device.

Personally, from the acoustic perspective, I prefer to use a sub seamlessly integrated into the speaker system (acoustically rather than physically that is), but some people prefer to have more obvious ‘bass effects’ going on - it’s all a matter of preference and perspective.