40hz room mode RPG Modex Corner trap?

I understand that the PARC might be a bit expensive. However, the Behringer DEQ2496 would do the job for you. See the several threads about this remarkable unit. By the way, Rives audio will tell you that LF room resonances, like 40 Hz, can't really be controlled by room treatments, and that is why they came up with the PARC.

Thanks for the info. I have a lot of respect for the PARC from everything I've read, and actually I've got a huge amount of use from the rives test cd with the rat shack meter while doing speaker placement and adjusting my asc treatments. $3k is probably too much for me at the moment though, wish there was a cheaper version that did just one mode.

Rives, is your thought on the Modex what I was thinking that it would take so many that it would be better to just use a PARC? Also curious if you have an info on building a Helmhotz resonator? Not actually out of the question as I have access to shop and lab equipment and would be looking at a 5-8db cut if I use optimum speaker placement.

Mondotrap looks interesting, may work in a corner for me.

I'll check info on the DEQ2496, probably stupid not to try it for the price. Probably would shift my direction to using an out board dac or something since my current digital player is optimized for tube analog out and doing A/D/A would give me an aneurysm. ;-)

Nik

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)