[mac]

Now that my system has settled down I finally got around to treating the ceiling. This has resulted in a phenomenal improvement in imaging. For grins, I'll have to run some MLS measurements to confirm what I'm hearing. Cheers, mac.

[davejcb]

That's great. I'm waiting on some 2" wedge foam from www.foambymail.com to get my first ceiling reflections, will post some measurements and results when I get it.

[ooheadsoo]

Cool.  How did you mount it?

[mac]

Cool.  How did you mount it?

3M heavy-duty carpet adhesive worked well for 1/2 hour so I resorted to using a staple gun.

[lt5dude]

I mounted mine with 3M double-stick tape that I found at Home Depot.  They make "normal" and "heavy duty" and I used some of both since I had some large and small pieces.  So far so good.

[jermmd]

I have a drop ceiling.  Could the foam be placed above the ceiling panels and still be effective?

Joe M.

[zachslc]

Just mount your speakers in the ceiling like they do at Best Buy.  Problem solved.

[mac]

I have a drop ceiling.  Could the foam be placed above the ceiling panels and still be effective?

Joe M.

Maybe.  For example, Owen's Corning makes many different acoustic ceiling tiles that have varying absorption properties.  If your tiles have a low coefficient they may be better at reflecting sound than absorbing it.  It wouldn't hurt to experiment with the foam.  Maybe trying some below (visible) and comparing the results with them above?  Another, although slightly more expensive, alternative would be to replace the ceiling tiles with ones that have a higher absorption coefficient.  For example: http://www.foambymail.com/DropCeilingTiles.html

[JLM]

Why not just cut foam to fit in place of the drop ceiling panels?

[LordCloud]

I've just ordered a couple of Metrofusors from the local pro audio store and I should be getting them next week. I plan on placing them at the first reflection points on the ceiling. Anyone have ay experience doing this?

[warnerwh]

Placing the foam at the first reflection points on the ceiling is the first place to do. Also you should use at least 3" thick foam as anything less doesn't do near as much good and it costs little more than 2" foam. 2" foam is only good to about 1khz, where 3" is good to 500hz and 4" is good to 250hz.  I'm using 4" foam on my ceiling and it helps alot. Also my room is LEDE so of course that helps alot too.  I use 3M spray adhesive number 77 and it works good. Also if you want to remove them the foam will come off easily.

[Red Dragon Audio]

I have a drop ceiling.  Could the foam be placed above the ceiling panels and still be effective?

Joe M.

I like the idea of cutting pieces to replace actual tiles.  If you put it above the tiles, it won't do anything really.  You can et cloth to match the other tiles and it would flow better visually.

I think one thing that seems to be kind of mis labeled is "first reflection point"...it really should be called "first reflection area". By the time the sound has travelled from your speakers to the wall or the ceiling the sound has spread out more and will reflect off more area than a single point.  Symantics I know... but I think it's important because you should be treating more surface area on the walls and ceilings than what is usually called "good enough".

Use the mirror trick to find out where the "first reflection point/area" is.  Then treat that general area with more foam/rigid fiberglass than just say 1sqft.  I have a feeling you will get better results from 4-8sqft treated than just 1sqft.  Of course do it to your own taste and liking while meeting all WAF codes.  


I talk alot of crap about treating rooms yet I still can't get my wife to approve no matter what.  I'm going to start painting water color pictures on lightweight linen which I will use to cover 2" thick rigid fiberglass panels.

[davejcb]

Also you should use at least 3" thick foam as anything less doesn't do near as much good and it costs little more than 2" foam. 2" foam is only good to about 1khz, where 3" is good to 500hz and 4" is good to 250hz.

I disagree. I bought this foam, in 2". If you look at the specs, assuming they are accurate, the 3" foam isn't that much better than the 2"... At 500hz you're looking at a coefficient of 0.89 versus 1.04. At 250hz, you're looking at 0.29 versus 0.48, so it's not a whopping difference.

In all reality, you're absorbing a few square feet with this foam. I can't honestly believe that it would have anything but a negligible effect on bass reproduction; that's what bass traps are there for. This foam is there to absorb higher frequency reflections, not to act as a bass trap. So to consider absorption coefficients below 500hz doesn't make a whole lot of sense to me. The 2" specs indicate that it will do fine above 500hz, which is what I'm interested in. That's why I went with 2", I didn't see the point in getting anything more.

[ooheadsoo]

At 500hz you're looking at a coefficient of 0.89 versus 1.04. At 250hz, you're looking at 0.29 versus 0.48, so it's not a whopping difference.

In all reality, you're absorbing a few square feet with this foam. I can't honestly believe that it would have anything but a negligible effect on bass reproduction; th ...

Actually, ratio wise, it's a pretty big difference.  Almost double.  But you're right, it's not going to do much for bass.  Fiberglass is better though, and I'm of the opinion that every bit helps.  I just mounted a small fiberglass panel above my listening spot at first reflection point.  Can't say I hear a difference for sure though.  IMO, my listening area was already pretty dead.

[Red Dragon Audio]

Actually, ratio wise, it's a pretty big difference.  Almost double.  But you're right, it's not going to do much for bass.  Fiberglass is better though, and I'm of the opinion that every bit helps.  I just mounted a small fiberglass panel above my listening spot at first reflection point.  Can't say I hear a difference for sure though.  IMO, my listening area was already pretty dead.

ooheadsoo is correct.  The NRC coefficients should really be read as percentages.

  .89 = 89% of the NRC standard  1.04 = 104% of NRC standard (for whatever frequency is meassured).

So there is a 15% difference between the two which is considerable.

At 250Hz the .29 and .48 coefficients represent a 19% difference.

Dave is also right in that you'd really want to use rigid fiberglass panels for low midrange and bass frequencies as foam just isn't as effective.

[davejcb]

Let me clear myself up... I realize that the 3" is 15% and 19% better respectively, I meant that in this application (covering a few square feet on the ceiling), it probably wouldn't have much if any effect to have 3" instead of 2".

In bass traps, that'd be a different story.

[Red Dragon Audio]

Let me clear myself up... I realize that the 3" is 15% and 19% better respectively, I meant that in this application (covering a few square feet on the ceiling), it probably wouldn't have much if any effect to have 3" instead of 2".

In bass traps, that'd be a different story.

good point.  

How are things going acoustically in your room?  My room is on hold as the bank wants double the money for our downpayment and that sux my savings dry.

I was getting all excited as the basement room was going to be my dedicated audio room.  Meaning I could use all the room treatments I wanted without punishment.  Not now though since my wallet was sucked dry.

[davejcb]

Just got my foam, MAN can those guys ever cram foam! 24 pieces in a box not bigger than 1' x 2' x 1'. I'll install it and post impressions ASAP.

[davejcb]

Posted a quick result here.

[michaelv]

will 3M double side tape damage the drywall if i decide to take it down? I'm looking for solution that i can stick the foam to the wall and , if i want to, take it off the wall without damaging the wall.

thanks.