3" or 4" rockwool panels?

gmcman

I have some Roxul and I plan on making some panels next week. Panels 3" tbick I feel would look better than using 2x4's but not sure how much I would be sacrificing.

Has anyone done 3" (2x3's) rockwool panels with desired results? I understand using 2x3's net less than 3" of material.

Phasewolf

3" will not deal with bass issues nor will the 4". The 4" will work better then the 3" in the midrange and higher area's and I would place a few inches of space behind them to maybe help them dig deeper then they would otherwise.

I am using 20" thick traps to get into the bass region and they still have issues going below 50hz.

gmcman

The bass issues aren't really a concern right now, just mainly first reflections and lowering my RT60 time.

What about ceiling tiles for panels? Filtering out maybe 250 or 500 Hz and above would these work?

Phasewolf wrote: »

I am using 20" thick traps to get into the bass region and they still have issues going below 50hz.

This is a good read and talks briefly about the wavelength of lower frequencies. Appears 50Hz is in the neighborhood of 3' thick of material

http://www.soundonsound.com/sos/aug98/articles/practicalacoustic.html

Phasewolf

RT60 above 100hz or so is not that hard to deal with to be honest. Things like carpet your couch and even your body help to cut down in that area. 4" would be fine for first reflection treatments what is on the floor if you have carpet then I would leave the ceiling alone it is not that hard to over treat the higher frequency and your goal is to keep the RT60 even throughout the entire range.

Thinks of it this way if you treat say about 250hz and not treat the bass the sound is going to be not even and will start to sound off.

And also just because you need 3 feet to 100% effect say 50hz does not mean they stop magically working below that point.

gmcman

Now that I have a preamp that I can tweak, I started messing around with the room eq it has built in. Not a whole lot to adjust but a few areas I can play with. It has limited adjustment and test tones, wish the treble adj would go down to 1kHz but 2 is ok. I could tell the vocals were just a tad in the background so the 2 kHz brought it forward slightly.

I also ran the test tone from 25Hz up to 300 and I had the most resonance at 76 Hz, then strong again at 120, 154, 248, and while it won't go higher than 300 it was starting again to get strong at 300 Hz.

Here's a screenshot of what I have and this smoothed things off considerably. I am going to pic up a mic this week for REW and play with it some more. I was just going by ear but the 76 Hz area was really bad and that's with some 2x4 sections of rockwool in the corners.

With a clean preamp now I can really make some tweaks and hear the differences. The room calls for 80 sq.ft of paneling so it's not over by a longshot but it's amazing the detail you can hear when everything starts to come together.

aboroth00

Here are the absorption coefficients for the panels:

http://www.bobgolds.com/AbsorptionCoefficients.htm

You pretty much won't absorb below 100hz with the thicknesses you're talking about. I would be careful about using overly thick panels to avoid overly deadening the room. I personally use 1" OC703 in all my panels for first reflection absorption. But you'll need thicker panels for the corners to absorb down to 75hz.

gmcman

Thanks for the link, a lot if info there. So I was experimenting more and decided to re-organize the rack and moved the amp up one shelf to use my .5 meter Kimber Hero from the pre. Was using BJC LC-1 which sounded very good but the Hero upped the ante slightly and needless to say I had to re-tweak my eq settings.

I still need the treatments but I was able to bring up the 76Hz and 155Hz slightly and it wasn't as muddy, highs are slightly more detailed as well. Not sure where that 3 hours went but I'm lovin' the fact any listening fatigue is now non-existant.

aboroth00

All the reflections probably cause the harshness you hear. I played around with treating first reflection points (front wall, floor, rear wall, side wall) and that helps immensely with detail, imaging and soundstaging. I treated the entire front wall but that greatly reduced the ambience and tightened the imaging to the center instead of beyond the speakers which I did not like. I ended up treating half the front wall just inbetween the speakers. However the <200hz peaks you mention are in the bass region and are better treated with bass trapping.