Thoughts on taming 50Hz peaks

[adauphin]

Since I changed my room around and relocated the TV and 2CH rig, I have added eight 48x15x3 Roxul panels mounted on the walls. I haven't treated the corners but after my last REW measurements, it appears there is a strong peak around 40-60 Hz. I messed around and moved the speakers out from 7" to 9" and placed a panel behind the speakers for a quick comparison.

The panels behind the speakers did reduce the decay time on the waterfall graph only slightly, but obviously that's not the best approach but just wanted to test.

I've included a sketch of the room, also showing where the 50 Hz sine wave showed it's highest levels.

This is with only panels on the wall.



One panel behind each speaker showed little improvement. I didn't expect it to do much, but wanted to only test. However, even being a very slight improvement, the overall SQ did improve, I was somewhat pleased to hear how even a small improvement in lowering the bass energy, allowed more detail to be heard in the rest of the music.



This is the graph with 1/6 smoothing.



This is the room which is very close to exact scale.



Same sketch showing the higher concentrations of 50Hz energy in the locations of the blue ovals. The larger the oval, the higher SPL. The area between the speaker is the highest, based on my SPL meter, the area between the tv is 6db higher than the listening position.



I also have a HVAC duct running the length of the room as depicted in the sketch, extending 35" from the wall. Effectively lowering the ceiling to 7'8" above the equipment.

I'm just not sure on what types of traps, absorbers, diffusers, are best suited for this application.

All input and criticism is greatly appreciated.

 

[Wayne A. Pflughaupt]

Moving the couch away from the wall would certainly help, but given the size if your room I’m guessing that probably isn’t an option. Parametric EQ is probably the best option. Traps and treatments are mainly going to improve low freq decay time. That will indeed sound better (as you’ve already seen), but it won’t do much to improve frequency response.

Regards,
Wayne

 

[Sonnie]

You have quite a lot going on below 500Hz that would probably sound significantly better if corrected. Above 500Hz looks really good, and that's where most of your room treatment will work best. For that low end, it's hard to fix it without some type of correction system, which I don't think your RLD-1 includes. I would look at a miniDSP of some variation to get Dirac Live involved.