[Carlman]

I recently had carpet installed and have a good amount of leftover 8 lb. 1/2" carpet pad with an 'odor/moisture barrier'.  I plan to use this somehow in my room... just not sure exactly how  yet.

My first thought was to use multiple flat layers in a frame and cover it with fabric on the rear wall.  Then I thought maybe I could make some rolls and use it as bass traps...

But, without an RTA or whatever... I'm kind of flying blind.  

I was curious if anyone had used this material before and to what results.  It doesn't cost much to experiment.... and the material is currently in the way... so, I'd like to use it sooner rather than later.  

Any suggestions are appreciated.

[Red Dragon Audio]

a while back someone was also inquiring about carpet pad uses http://www.audiocircle.com/index.php?topic=13787&highlight=carpet+pad">here.

If you roll it up, I'm sure it will make a good bass trap.  If you have enough, you could make a few tubes for the corners of your room.  Pick whatever fabric suits your style.

I know Jim Fosgate lined his theater room with carpet pad and then a layer of carpet over that on the walls then stretched fabric over that for looks.  It was a very quiet room until he cranked things up.  He had a full range 5 channel setup with 4-10" woofers per channel along with a few SEAS mid-drivers and the SEAS millenium tweeters.  Lots of fun that setup.  

...but I digress...

Please test the carpet pad and let us know what you think.  Marvda1 from the other post hasn't reported back yet on his results but Roc said he used 6ft rolls for years with great results.

GLHF

[Uptown Audio]

It depends upon what you want to accomplish. Varying thinknesses and forms (such as a tube for bass) will absorb different frequencies. I placed a section of carpet pad on the side wall just ahead of the speaker (the first reflection point) and covered the pad with a tapestry. It is a single layer and so will only absord higher frequencies.
It can take as much as 4" to aborb anything into the midband, so that may not be an option (and is usually unwanted anyway). You don't want to absorb anything but troublesome frequencies as the point of having a system is to produce sound, not absorb it. You would then be basically fighting the amplifier, which is silly.
You should however, take a room measurement from the listening position, using a test CD and an SPL meter to create a graph. Once you know what the in-room response is, you can then make adjustments as you find they are needed. Flat is good and generally the desired goal, but listening and deciding for yourself what you would like the system to sound like to make it most realistic is even better.
My room has a peak at around 30hz and since my speakers have a natural roll-off at around 30hz, it is a good synergy and I get deep, powerful bass. Not a bad thing and nothing that I really feel too compelled to "correct". The first reflection points are worth looking into and with a nice frame and a tapestry or colored, patterned, or textured cloth covering of some type, you can make a attractive panel that looks as nice as it helps the sound if the colors complement the room.
-Bill

[Carlman]

I know how critical the first reflection points are... I did a quick comparison of moving mine for a fellow AC'er when he was last at my house.... BIG difference.

That same friend that was over brought his TacT and we did some room measurements.  I too have a 30Hz bass peak... but it's huge... like +6db, maybe more... can't remember exactly now.  I have another (much smaller) peak in the upper midrange, around 1,k.  Correcting that upper midrange really helped the speakers dissappear better... and the bass was cleaner but I would've likely bumped it up a little more than flat.

I still have the carpet pad in a huge roll in the garage... I was thinking it may tame that huge bass peak.  I also have a single roll of regular fiberglass I could upholster and use as an ottoman.  

I'd rather over-damp and go backward... I'm tired of adding a little and it sounding nicer.. and then adding a little more.. and more... Why not just add a ton and remove if it sounds bad?  Seems easier to me.  I guess it's more of a question of which easier, pushing or pulling?  

OT... Happy 2000th post to me.

-C

[John Casler]

I'd rather over-damp and go backward... I'm tired of adding a little and it sounding nicer.. and then adding a little more.. and more... Why not just add a ton and remove if it sounds bad? Seems easier to me. I guess it's more of a question of which easier, pushing or pulling? quote]

Your 100% correct.  As far as I'm concerned the term "overdamped" is a misnomer.  It means "I prefer to hear my room".

I live in an "audio world" where any room interaction is a negative to accurate reproduction.

I have spent hundreds of hours listening in a reasonably good anechoic chamber, and it was some of the purest sonics, I had ever heard.  It was limited only by the quality of the equipment I used.

I would suggest that the goal of acoustic room treatment could be only one two results if one is interested in accurate reproduction of what is recorded:

1) Duplicate the exact acoustic profile of the recording engineers room

or

2) Make your room boundaries as "acoustically tranparent as possible".

Most every tweak I use furthers this goal and it just sounds better and better

[Ethan Winer]

Bill,

> It can take as much as 4" to aborb anything into the midband, so that may not be an option (and is usually unwanted anyway). <

You are correct that first reflections and imaging are mainly a midrange / high frequency issue, but comb filtering occurs down to the lowest frequencies and is always best avoided. Another advantage of absorbing to lower frequencies at the first reflection points is it adds that much more bass trapping into the room, which is always welcome.

--Ethan

[Carlman]

Well, I tightly rolled my carpet pad into a roll... and had it in the garage for a long time... and in the garage I could actually 'hear it'... it had an eery silence around it.  I walked by it every day and finally decided to tote it inside...

Now, you may be expecting me to say 'wow', right?  Well... no... it made no audible difference I could detect.  I guess it was a fun experiment for free but it's definitely not a bass trap.  It's a good echo-tamer or something... but that's about it.  

I've had it in there a few days... I threw some microfiber fabric over it to make it pretty and see if that made any difference.... but no... no difference.. and isn't really 'pretty' either.  I could probably suspend this roll from my ceiling horizontally to kill the first reflection point on the ceiling but man... talk about low WAF...

Anyway, I know photos would be helpful and maybe I'll take a few... I'd also like to see an RTA and see if it 'hears' a difference...

-C

[csero]

I have spent hundreds of hours listening in a reasonably good anechoic chamber, and it was some of the purest sonics, I had ever heard. It was limited only by the quality of the equipment I used.  ...

C'mon, having six towels hanging is not an anechoic chamber  

[John Casler]

I have spent hundreds of hours listening in a reasonably good anechoic chamber, and it was some of the purest sonics, I had ever heard. It was limited only by the quality of the equipment I used.  ...

C'mon, having six towels hanging is not an anechoic chamber  

HI Frank,

     

The anechoic chamber of which I was refering was created in a small room and I had somethin like 10 old cotton matresses to line the floor, ceiling and the walls.

Over that I placed some acoustic foam.

All that was inside was a pair of speakers, an overstuffed ottoman, and a CDP.  (all the electonics were outsided and operated RF)

I didn't say it was a perfect anechoic chamber, but a "reasonably good" one

The sound, even with "so-so" equipment, was incredible.

The speakers only went down to around 50Hz, so bass wasn't an issue either.

Spent a lot of time in that room critcally listening and loved every minute.

It is always funny to hear how many people "state" how listening in an anechoic chamber sounds "dead".  First of I can guarrantee that 99% of those "claiming" such have never spent more than 2 minutes in a reasonable chamber, and exactl "ZERO" time critically listening to musice in two channel, in the sweet spot.

The interesting thing is that excluding most of the "Sonic Fog" reflections that most listen to, actually increases dynamics, detail and resolution when listening in the sweet spot.

[youngho]

John,

Perhaps if you have some extra time, energy, and money, you might try constructing a chamber like this: http://www.roger-russell.com/cham2pg.htm

I'd be interested in hearing loudspeakers in an anechoic chamber, but then I wouldn't be able to enjoy that great Stereo Everywhere® performance from Direct/Reflecting® technology.

Young-Ho

[John Casler]

John,

Perhaps if you have some extra time, energy, and money, you might try constructing a chamber like this: http://www.roger-russell.com/cham2pg.htm

I'd be interested in hearing loudspeakers in an anechoic chamber, but then I wouldn't be able to enjoy that great Stereo Everywhere® performance from Direct/Reflecting® technology.

Young-Ho

   

Yeah, I think it would take a "LOT" of time, energy, and money (especially money) to build that.

But, it would no doubt "suck out" most of those "pesky" room interactions