[OBF]

Hi.  I'm thinking of buying a new house that is still being built and was just reading Ethan's acoustics FAQ and have a question (probably more).  I was talking to the builder about soundproofing as we had previously discussed adding a 16x20 "shop" in the back yard for an entertainment room, but decided against it because of the cost.  The house has a daylight basement that is approx 14x22 and 3 of the 4 walls will be insulated per code requirements.  He said he could insulate the ceiling (looks to be built with 2x10s) and "hang" the drywall ceiling with some part I didn't remember.  In the FAQ Ethan says you can fill an unfinished ceiling with a foot of fluffy insulation to get bass trap characteristics.  I'm wondering if filling the entire space will reduce this benefit and also if it has to be open to work.  In other words, will the ceiling material remove any benefit to having the space above it stuffed with insulation?

[warnerwh]

Greetings:  The builder may have been talking about hanging the ceiling with resilient channel which is a good idea. I just did the same thing but there's a layer of soundboard against the joices and then reslient channel and sheetrock with a layer of acoustic tile under that.  I can rock out down here and although you can still hear it upstairs it sounds as though it's in the distance and is not annoying to those upstairs.  It helped alot and didn't cost that much.  Being as you're starting from scratch do your homework, a very worthy endeavor.  Room acoustics are a huge part of the sound from your system, only second to speakers.  Be sure to budget in some sound treatment for the room. If you need any help let me know.

[OBF]

Thanks for the suggestions.  I thought he said something about hanging with R-(some number), but it didn't mean anything to me.  I definitely want to address both acoustics (plan to try and find some of the OC rigid fiberglass) and noise since I also like to rock out.  The house I'm in now is fairly new and it has thin walls and doors and no insulation and it's basically impossible to listen to music downstairs over 80db and still watch tv upstairs.  It's a real bummer.

Are your acoustic tiles attached to the sheetrock, or suspended like a drop ceiling with air between?

[Ethan Winer]

OB,

> He said he could insulate the ceiling <

I'm not much of an isolation expert but I can answer some of this.

If you put one foot of fluffy fiberglass between the joists and then cover it with sheetrock, you will cancel the bass trapping added by the fiberglass. But the fiberglass is still useful there because it improves the isolation.

If the contractor suggested that fiberglass alone will give you isolation - you said he used an "R" number - he is mistaken. Having fiberglass between the joists is better than not having it, but that alone won't give much isolation.

Understand that good isolation and good low frequency response are competing goals. What helps one hurts the other. You can have both, but it's expensive. If you really need isolation you should install a sheetrock ceiling, hung from resilient channels, and you'll also need a fair amount of bass trapping inside the room.

--Ethan

[OBF]

If the contractor suggested that fiberglass alone will give you isolation - you said he used an "R" number - he is mistaken. Having fiberglass between t ...

Ethan,

After doing a little research, I think it was the resilient channel he was referring to, RC-2, as that now rings a bell.  At this poing, isolation is more of a requirement than perfect bass response.  That's important too, but if I can't use the stereo response won't do me much good.  However, I will plan to install bass traps in the room as it's fairly long and I should have plenty of corner space.  I just hope his people know how to install the channel properly as it sounds like you have to do it just right or you lose most of the benefit.

[JLM]

The metal "U" or "Z" shapes are roughly 3/4 inch wide and isolate the drywall from the bottom of the joists.  The loose fiberglass insulation would also help isolate between upstairs and down.

Replace metal ductwork with lined fiberglass and have dedicated circuits with their own grounding if you can.

Proportion the room by the "correct" ratios: 1 x 1.618 x 2.618.

Try to put one side or back wall on a slight angle (skew) to the rest to help break up standing waves.

[warnerwh]

OBF: The sheetrock layer hangs from the RC 1 to which I attached acoustic tile.  I have VMPS Supertower/R SE's.  These speakers put out the bass I can assure you as there's 2 15's and a ten in each side powered by a Parasound Hca 3500. At times I like to listen to music at what most people would consider quite loud or peaks in the mid 90's.  The female upstairs is happy.  The acoustic tiles are 12" pieces glued directly to the sheetrock.  If you do want to use these also you need to get of a building supply store for contractors. Home Depot didn't have diddly.    Also this was the most expensive part, 250 for a 12x17 room.

My walls are just standard 2x4's with sheetrock.  There's sound that does get through to the upstairs but it's not that bad at all.  Of course that ceiling cost several hundred dollars but I can listen to whatever I want whenever I want.  Also Cheryl is a bit more forgiving I think than some women as I've cranked it and gone upstairs and it would probably bother some people although you can still watch tv which is directly above my listening room.  You can come over sometime if you want to drive this far and see/hear for yourself.  

Do your homework. I wish I'd have put insulation between the joices but didn't as I read it did nothing for soundproofing. Had I known it would help the bass I'd have spent the 15 bucks or whatever. I've ended up building two more bass traps and a third is on it's way btw.  Being as your room is not finished think it through and be patient.  

The room treatment and acoustics issue is huge.  I actually bought myself an Audio Control C101 III equalizer.  A little judicial equalization makes quite the nice gain in sound quality, more so than not having an equalizer in line.  After all these years my opinion is that a quality equalizer could help numerous people but they are too stuffy to try it.  Amazing what a couple db boost or gain here and there will do to the overall sound!  My apologies for such a long post but I just finished my room a few weeks ago so know what you are going through.

[Ethan Winer]

OB,

> the resilient channel he was referring to, RC-2 <

Okay, yes, that will help.

--Ethan

[OBF]

Warner,

I wouldn't mind checking out your setup sometime.  I'll PM you if I'm going to be up that way and have extra time.  I'd like to hear the Supertowers anyway.

Thanks.