40hz room mode RPG Modex Corner trap?

My experience is that a digital notch filter at 40Hz with a 6 Hz width worked fine for me....this kind of bass management adjustment is available on most DSP's because room resonance is such a common problem with subs that extend down to 20Hz.

Obviously this is not ideal but I think there is a limit to what can be achieved with room treatments. So your choice is either electronic tweaking using a DSP or the rather costly option of moving house and using a gymnasium size room for you system...

I am not sure if you can get an analog filter that would do the job adequately ( at least not cheaply as complex analog filters are very expensive )....digital filters are much easier to design and can still give great performance(in my mind).

Shadorne, can you recomend a unit that I look into? I guess it still puts me in the boat of going to a transport dac system, but I suppose I could try a TACT system or something.

Nik,

I think most DSP's have digital notch filters.

I have an Anthem AVM 20 (second hand of course) which I feel is great value considering all the features and XLR outs. Good enough for me anyway. There are many other DSP's and some with more expensive DAC's than the AVM 20...so look around...maybe a Krell or Classe.

Myself I am not so worried about DAC quality and have not tested a lot of high end DAC's. I have never heard a TACT 2.2 for example - so I am not sure I can advise which DSP has the best. I am far from an expert on the various DAC's. It seems to be a whole area that I can't fathom....once distortion + noise figures get close to one hundredth of 1% then I feel well satisfied. (as my speakers put out 100 times that level of distortion.)

All I can say is that my AVM 20 helped clean up a nasty 40 Hz bump I had from room standing wave....no doubt other DSP's can do the job just as well....after all digital filters are just software programs. And I am almost certain that I could not achieve the same sharp notch with an analog EQ (at least not at a reasonable cost)

Nik--sorry been away from the gon for a while. The Modex has not been effective in our practical experience. It wasn't even an issue of how many. As to the Helmhotz--these are very tricky. Alton Everest does a nice write-up on them in Master Handbook of Acoustics. The issues become how rigid to make the box (determines Q factor) and how large (determines db drop).

I'm trying to learn about this stuff, too. So, my comments are those of a seeker, not an expert. I think the Behringer goes between pre-amp and amp, operates in the digital domain, and its output must be converted back to analog. So, it's not the best approach for someone using an analog (vinyl) front-end. The Rives PARC is all analog, which IMHO is a better hi-fi approach. The trade-off is that Behringer offers something like 32 bands, while PARC offers three. But I think three bands is enough, because this allows you to flatten the first three room peaks, and multiples thereof. And, whether with Behringer or PARC, you still need bass traps for the nulls. At any rate, I wouldn't use Behringer in my system. I'm saving my pennies for Rives PARC.