50Hz peak

Posted by: marczed on 01 April 2004

Greetings.

I have been a naim user since November of last year.

System -:
NAC252 + Supercap
NAP300
CDX2 + XPS
Naim Allae

Over the years I have owned a few different systems. Whilst this one is by far the best, I still suffer from a distracting and pronounced peak at around 50Hz which is sufficiently dominent to mask lower frequency bass. I have tried every available speaker position (within reason).

I can only assume that it is the shape of the room that is the cause of the problem. It is 'L' shaped. The 'main' part being 20' long by 12' wide and the 'other part' being 9' square. I have tried 'firing' down the length of the large part as well as across the smaller width of the room. This makes no difference to the 50Hz resonance, but the imageing is much better firing lengthwise, so thats how it is set up.

Question -: would I achieve a better balance by upgrading the speakers to a larger type capable of going lower? I realise that the only way to find out is to try some, but any comments would be helpful.

PS I used a CD test disk with frequency sweep which clearly makes the room 'take off' at around 50Hz.

Posted on: 01 April 2004 by Allan Probin

Your 50Hz peak is a result of the 12ft room dimension. I used to have a very similar problem in a 14ft x 11.5ft room. The 50Hz peak was something like +20db and even using a number of tuned bass absorbers couldn't elliminate the problem.

This was when I had the speakers firing parallel with the 11.5ft walls. Moving the speakers to fire down the length of the room totally elliminated the 50Hz peak. It was replaced by a peak at about 38Hz but lower in amplitute and much less noticeable. In fact, if anything, my system sounds a little lightweight now.

I notice you've tried this already and you still have a 50Hz peak. My experience however is with SBLs. I think it's unlikely that the SBLs and Alleas have very different characteristics but my conclusion was certainly that the resonance was very dependent on the speaker orientation.

It might be worth trying SBLs if you can borrow a pair, just on the off-chance that SBLs are more directional in this respect.

Allan

Posted on: 01 April 2004 by Markus S

Or build a Helmholtz resonator to tame the peak. If your room has a very specific resonance, this is a proven way to get rid of it.

Posted on: 01 April 2004 by Greg Beatty

If it turns out to be truely independent of speaker position, it is possible that something else is going on. What is your kit sitting on? Feedback through the kit possibly?

- GregB

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