Connecting subs on a nac552dr

DSP definitely delays signal by a significant margin…I think Xanthe uses REW on the whole system…which would work just fine…but I may stand to be corrected…

I can’t see how DSP working just on the sub could ever correct for any timing delays, it would need to work on the whole speaker set-up by delaying the signal to the stereo pair to match the sub delay?

Agree DSP need to be applied to whole lot…using something like REW or Roon

I do agree with these delay considerations about dsp,but I’m afraid of the idea to place a dsp between a nac552 and a nap500(with its cabling issues,but feasible)in order to put the right delay on the front speakers.Are you aware of someone who tried this experience?
And if not using a dsp for the subs,they will be delayed anyway by their own crossover,won’t they?

The subs x-overs are pretty fast and don’t forget the main speakers have an x-over to. DSP is different the signal will need to converted into digital adjusted and then back again. If I use DSP I use Roon its all done at the digital source end… but this is no good for analogue record players… Try connecting them without dsp…adjust the cut off frequency to match your speakers…then reduce volume right down… to get to point where the sub disappears … you may need to move the sub around … try it. If I were you I would try both the high level speaker connect … then try the output 1 and Mogami…

Has anyone asked the OP what make and model sub (s) he has?

Not sure about what op means,sorry if I reply for someone else😉my two subs are a piega PS2,wonderful sub with both hi and low level inputs,and a B&W db1d only equipped with low level inputs.
My preference would be what some forumers advised me to at first,connecting my speakers to the piega high level inputs but there seems to be an issue,I don’t understand what it is precisely,proceeding this way with a nap500dr amp.if risky I won’t go for that.
The other way that seems good is what richerioo did,using a 5m Mogami interconnect from the nac552 to both subs.
Definitely no dsp for me,due to delay issues.
I’ll try to reach naim in order to find out if we can connect the nap500 to the hi level inputs of a sub.
Thanks a lot for your help

Hi Max. OP is Original Poster.

Hi Opus,thank you!

When Naim made the N-Sub they said it was possible to use it with bridged amps like the 500, but that it required a special cable arrangement. I believe this is to do with the grounding arrangement, but I’m not absolutely certain how best to deal with this, so best give Naim a call.

Ok ChrisSU I’ll get in touch with them,after a week no answer from them…

If your dealer is any good, he should be able to sort this out for you. Or perhaps your distributor if you are in France?
I generally find that it’s best to contact Naim by phone rather than email if you want an answer.

I just gave a call to naim’s French distributor.he confirmed me there could be some issues connecting the sub hi level inputs to the nap500,something about cable capacitance(hope it’s the good word in english😂)and the better way to proceed was to use the third nac552 variable output.Nothing was said about which kind of cable,maximum length or whatever…
I do thank all of you for your kindness and your advices!

Naim’s old sub lead might be a good guide; the cable was low capacitance, the maximum length offered was 10m, and the lead was slugged with, IIRC a 100R resistor.

Wasn’t aware of this one,I’ve just emailed witch hat asking what they think about connecting Nap500 to sub’s hi level input,waiting for their reply.îll let you know As soon as I get it.

Shouldn’t you be asking Naim that…?

I did about ten days ago,but no reply from them.
Witch hat staff gave me their point of view,here it is:

Connecting it via the speakers, probably wouldn’t cause a problem in practice as Naim’s main capacitance issues are to do with minimums and this would add it in not take it away. We do have a customer who has set his up this way but has a heavily modified system and therefore shouldn’t be taken as a guide on what is correct, though the engineer does mention that the sound from the speakers will probably be more inclusive vs coming from the pre-amp.

I’m not sure about what “inclusive” means as we use the same word in French but it makes no sense to me also in my language😂

It makes little sense to me in English.

Personally, I’d phone Naim and ask them - they may pass you from person to person, but you’ll likely get a definitive answer that day. They are probably overwhelmed with email and are not quick at replying to it…,

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The group delay in the DSP is likely to be about 0.1ms.
The group delay in the sub is likely to be 2.5ms to 5ms.

The main delay is in the sub itself, the delay in the DSP is irrelevant in comparison.

(Incidentally if you have reflex or open transmission line speakers than these will have an even greater group delay as you appraoch the port tuning frequency and below that point.)

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The problem with connecting a sub to the speaker terminals of a NAP500 (or any other bridge amp) is not to do with cable capacitance; it’s that the high level inputs of some subs use a common 0V reference, to which the 0V inputs are both connected.
If this is the case, at worst it can severely damage many types of bridge amp, and at best it will just push the amp outside its operating envelope.