I really need help with a DIY sound room.

[pixie]

It looks like the medium velour is what I want. Now, what is half area again? And, what will it do to frequencies above 4kHz?

Thanks,
pixie

[PassFan]

Pixie:
The author states that frequencies above that point are usually not much of a problem and very easy to control. You will probably have to find a balance inbetween. For example if the velour drops 3.5k too much pick a material that has a low absorption in that range and reflect it a little bit. You may also look for any books on architectural acoustics. Good luck

I'm not sure what the chart means by half area. Maybe half the surface area of the wall your treating.

[Super]

Just a quick side note, but compressed fiberglass mats can sometimes be had from your local HVAC, or in inexpensive drop ceiling tiles. They can be effective as well.

Oh, by the way, I'm not sure if anyone else has tried this tweak, but has anyone put sand filled enclosures near their subwoofers? I had some pretty bad wood floors in the house, and they shook like crazy when the sonosub was doing its job. I added a few sand filled buckets around the floor, and it seemed to tighten up the bass considerably and help control resonances. Just a thought...

[dice45]

Originally posted by BAM







... and with frequency response down to 20 Hz using a Linkwitz Transform circuit. .......















that are actually a better source for information on designing a Linkwitz Transform than Linkwitz's own site, from my experience. A spreadsheet is widely available that will allow you to input the Ftc and Qtc of the sealed enclosure and get the values for the capacitors and resistors and stuff.

Hello BAM,







are you talking about the Linkwitz pole shifting filter?







I could provide info, I have copies of the original articles pubished somewhen in the 70ies. A buddy used it to build a sub, worked extremly good.















I would be very glad to have some links to what you call the Linkwitz Transform and to the spreadsheet. I did my calculations not with a spreadsheet, i used MathCAD.















Hello Gemini,















may i suggest you put some book shelves and record shelves into your new listening room ? Please use shelves big enough so that you can have them filled to not more than, say, 70 %. Even better if you mix book s and records, and you push all of them to the backwall of the shelf so that you get an utterly statistic and uneven surface. Then you have the finest acoustic diffusors, and more, they are large surface. They act like RPG diffusors ( http://www.rpgdiffusors.com/ ), just you don't have to pay for them $$$ . If you have parallel walls, neutralize one of them with a book shelf. Don't put the shelves behind your speakers, i am sure you will place them with atleast a meter of air around them to have a good 3D soundstaging, so you will need the backwall reflections. but if behind your listening chair are bookshelves, just fine. Use some "skyline" RPG diffusors for the ceiling.






The basic concept is, DON'T destroy acoustic energy by excessive damping means, you have paid and worked so hard to generate then, spread the room resonances instead of killing them.










I did so the last 10 years, always having impossible acoustics in my rooms before that, but not after careful shelf placing. Never had complaints from buddies about room acoustics. Just, cannot afford the RPGs so far, but heared their sonic influence at a local hifi shop.