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40hz room mode RPG Modex Corner trap?

Hey guys,
Looking for some help with some room modes I am battling. Main offender is 40hz mode. (very typical with 8ft ceilings I suppose) I have several ASC tube traps that have helped a lot, but at this point the don't need much more broad bass damping just 40hz damping as the peak there is way above everything else.

So, two questions:

1. Has any one used the RPG Modex Corner trap?
http://www.rpginc.com/products/modexcorner/
Seems to be exactly what I need as they make a 40hz model. How effective are these? I think that to make a significant difference I may need so many that the cost will kill. Would 2-4 make a difference?

2. Any other ideas to kill the 40hz room mode short of an eq like the PARC?

Thanks
Nik
nikturner920

Showing 2 responses by shadorne

shadorne's avatar
shadorne
7,477 posts
 
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's avatar
shadorne
7,477 posts
 
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)
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