NAC 152XS sub outs question
Posted by: awn on 14 February 2016
Hi, just wondering if anyone knows if the sub outs on the 152XS are split? As they are labelled with a left and right, do they only output low frequencies from each channel, or are both sub outputs just regular sub outs (both channels combined)?
The reason I ask is that on my previous amp, I was running dual subs in stereo, not full sub signal to each sub. But, when I hooked them to the 152 sub outs, I had to turn the sub volumes down quite a lot.
Thanks in advance.
I used to have 152XS, and I run subs in the 2ch part of my system, so hopefully I can help.
The sub outs are effectively just an RCA pair of stereo pre-outs. There's no processing in the 152, so you get full range audio in stereo coming out of these.
As a result the gain level is the same as goes to your Naim power amp, and any filtration to cut the frequencies coming out of the sub must be done using the crossover controls on the sub itself.
You don't mention which make of sub, or main speakers, but I'd start the fine tuning by setting the sub crossover around 80Hz, gain around a third to half of max. Then start dropping the gain until just past the point where the sub appears to not be doing anything from the listening position. Then roll it back up a pinch.
Once that's right, do the same with the crossover frequency.
Go back to gain and do it again. Then back to crossover.
Once you've don't this five or six times you should be able to enjoy the music without noticing the subs, but if you then turn the subs off and repeat a track it should be obvious that 'something' is missing.
Hope this helps
Mike
I have recently installed a minDSP 2x4 to do the crossover to the sub (connected to a Nait XS-2, so very similar to the NAC 152). This has the advantage that not only can you accurately control the crossover (frequency, slope, volume and delay), but you can also use the DSP to apply a room correction curve just to the sub output, leaving the main signal unaltered.
To set it up I used REW and a calibrated microphone (a miniDSP UMIK-1). The result has been very successful and much better than when I did it manually.
Mike1380 posted:I used to have 152XS, and I run subs in the 2ch part of my system, so hopefully I can help.
The sub outs are effectively just an RCA pair of stereo pre-outs. There's no processing in the 152, so you get full range audio in stereo coming out of these.
As a result the gain level is the same as goes to your Naim power amp, and any filtration to cut the frequencies coming out of the sub must be done using the crossover controls on the sub itself.
You don't mention which make of sub, or main speakers, but I'd start the fine tuning by setting the sub crossover around 80Hz, gain around a third to half of max. Then start dropping the gain until just past the point where the sub appears to not be doing anything from the listening position. Then roll it back up a pinch.
Once that's right, do the same with the crossover frequency.
Go back to gain and do it again. Then back to crossover.
Once you've don't this five or six times you should be able to enjoy the music without noticing the subs, but if you then turn the subs off and repeat a track it should be obvious that 'something' is missing.
Hope this helps
Mike
Thanks mike, so given that they aren't actually true "sub" outs, and they are just another set of pre-outs, then each one only outputs its given channel. This is what I wanted to know, great for running stereo subs. It makes me really wonder though, why the output is so much louder than my previous NAD pre outs, which I drove my subs from in the same way.
It's because Naim power amps have an input sensitivity of 775mV, so that's what their pre-amps output.