# Floor Bounce Solution



## jim1961 (Apr 8, 2011)

Using ETC measurements, I am getting a -17db floor bounce. I would like to get that below -20db if not lower. I have tried every rug I have and piling them on top of each other also. I know its a floor bounce and where because when I put a scrap piece of 2" OC703 on the right spot, the ETC drops to -21db. Problem is, I cant leave a 2" piece of fiberglass on the floor without tripping over it. Ive tried blocking the bounce but the size "blocker" I need to deal with it effectively looks bad and gets in the way.

I have heard wool or cotton does better than synthetic rugs. True?


----------



## robbo266317 (Sep 22, 2008)

Wool would be the best option. 
What is the floor made of?


----------



## jim1961 (Apr 8, 2011)

robbo266317 said:


> Wool would be the best option.
> What is the floor made of?


Pier house with OBC over 2x6, carpeted.

edit: Looked into wool shag. Geez, that stuff is expensive. Going to have to find a different solution I think.


----------



## robbo266317 (Sep 22, 2008)

How about some soft footstools or a coffee table to break up the path? :scratch:
I don't know if that would work. bpape would be the best person to ask.


----------



## jim1961 (Apr 8, 2011)

robbo266317 said:


> How about some soft footstools or a coffee table to break up the path? :scratch:
> I don't know if that would work. bpape would be the best person to ask.


Anything that has a flat top would have to be absorbent otherwise while you block one set of reflections you create a new set of them (I looked into this).

I am already using two footstools directly in front of the listening position that have open bottoms that I stuffed with R19 that are helping noticeably. 

The spot on the floor that needs additional treatment lies directly between your head and the speaker. And this spot is also a traffic area unfortunately. 

Is it customary here to invite users to threads via messaging?


----------



## robbo266317 (Sep 22, 2008)

No, normally they are browsing and pick up on questions. You may get more responses in the Room Treatments forum if you post there.


----------



## jim1961 (Apr 8, 2011)

robbo266317 said:


> No, normally they are browsing and pick up on questions. You may get more responses in the Room Treatments forum if you post there.


I went to the site navigation link and didnt see a forum called "Room Treatments".


----------



## ALMFamily (Oct 19, 2011)

Bryan (bpape) may be on vacation - I PM'd him a few days ago and have not heard back from him.


----------



## jim1961 (Apr 8, 2011)

ALMFamily said:


> Bryan (bpape) may be on vacation - I PM'd him a few days ago and have not heard back from him.


If you mods think this should be in a different forum, then just move it for me if you can.


----------



## jim1961 (Apr 8, 2011)

Well, after thinking i'd tried everything I had on the floor area in question, a thin cotton weave rug (2x3) gave a surprising result. Thought id given it a shot before but apparently not because its turned out to be the best performer of the lot. Given that its at least twice as thin as other rugs ive tried, it must be the cotton material that makes the difference. I suppose I should have already known that :scratch:

Anyway, it made a 2.5db difference over the best thing Id had there before. And quite cheap and available, $4.95 at Walmart.

I am still not completely happy, but am closer :clap:


----------



## ALMFamily (Oct 19, 2011)

jim1961 said:


> If you mods think this should be in a different forum, then just move it for me if you can.


I think it fits here - Bryan will hopefully chime in soon.



jim1961 said:


> Well, after thinking i'd tried everything I had on the floor area in question, a thin cotton weave rug (2x3) gave a surprising result. Thought id given it a shot before but apparently not because its turned out to be the best performer of the lot. Given that its at least twice as thin as other rugs ive tried, it must be the cotton material that makes the difference. I suppose I should have already known that :scratch:
> 
> Anyway, it made a 2.5db difference over the best thing Id had there before. And quite cheap and available, $4.95 at Walmart.
> 
> I am still not completely happy, but am closer :clap:


That is good to hear - and I would have never thought cotton would make the biggest difference....:scratch:


----------



## jim1961 (Apr 8, 2011)

Thought id post the actual results.

Black = Before
Red = After (with cotton weave rug)

ETC unsmoothed 450hz-5.6k 0-10ms

The part I was focusing on most was right after 2ms.


----------



## Kal Rubinson (Aug 3, 2006)

I have a 3'x3' ottoman in front of the listening position. It is an upholstered frame with the inside filled with OC705 so it is a fairly decent absorber and it is placed where it blocks the direct floor-bounce reflection (from the carpeted floor).


----------



## jim1961 (Apr 8, 2011)

Kal Rubinson said:


> I have a 3'x3' ottoman in front of the listening position. It is an upholstered frame with the inside filled with OC705 so it is a fairly decent absorber and it is placed where it blocks the direct floor-bounce reflection (from the carpeted floor).


Do you have ETC's of with and without?

Assuming your speakers are about 30 degrees (L&R) from direct center, a 3' wide ottoman wouldnt be between your ears and the speakers in this case would they? I too have footstools with open bottoms filled with R19 directly in front, but its along the line of sight from me to the speaker(s) on the floor where I am having problems (see rest of thread for further clarity).


----------



## Kal Rubinson (Aug 3, 2006)

jim1961 said:


> Do you have ETC's of with and without?


I did but don't know if I can find them. Next time I do some measurements, I will redo that.



> Assuming your speakers are about 30 degrees (L&R) from direct center, a 3' wide ottoman wouldnt be between your ears and the speakers in this case would they? I too have footstools with open bottoms filled with R19 directly in front, but its along the line of sight from me to the speaker(s) on the floor where I am having problems (see rest of thread for further clarity).


If one assumes the reflection to be completely specular, it does interrupt the center bounce directly and not the L/R. However, it seems to affect the L/R bounce as well although to a lesser degree.


----------



## jim1961 (Apr 8, 2011)

While my floor bounce is very real, a portion of what I am seeing is ceiling and the listening chair. 

Maybe things are good enough if I am down thinking about out how to know what the ETC is with someone in the chair? (the measurement computer is in an adjoining room)


----------



## Tonto (Jun 30, 2007)

When I was shopping the carpet for my room, the salesman gave me a sample of acoustic foam padding to look at for to use as the carpet pad. I didn't give it much thought at the time, but it would probably do more than the cotton material. Sound like you don't need much, maybe call your local carpet store & get a peice for under your rug & give it a measure. Let us know how it works if you do.


----------



## robbo266317 (Sep 22, 2008)

I'm glad you were able to make an improvement. Do you have any pics of your room?


----------



## ALMFamily (Oct 19, 2011)

robbo266317 said:


> I'm glad you were able to make an improvement. Do you have any pics of your room?


+1 - Would love to see them as well!


----------



## jim1961 (Apr 8, 2011)

I wish I had some pics to share, unfortunately I dont.

Today, putting the cotton rug down makes the reflection worse, not better, but only on one channel. Go figure? Obviously there is some complex wave bouncing going on. I made a ceiling cloud change. Must have changed some angles or something.

Working with ETC responses I find sometimes is like working with a balloon. You push in on one side and it just gets bigger somewhere else. Conversely, fixing (treating) a reflection in one place changes the response in others. Very frustrating sometimes. 

I may have access to a digital camera at the end of the month. Will post pics then if I can.


----------



## jim1961 (Apr 8, 2011)

robbo266317 said:


> i'm glad you were able to make an improvement. Do you have any pics of your room?













































This ended up being my solution to the floor bounce.













With this result (unsmoothed ETC 450hz - 5.6k). Not perfect, but acceptable. Thanks everyone for your input!


----------



## robbo266317 (Sep 22, 2008)

Well done! That is a neat solution. :T

Did you make your QRD's or are they commercial ones?


----------



## jim1961 (Apr 8, 2011)

robbo266317 said:


> Well done! That is a neat solution. :T
> 
> Did you make your QRD's or are they commercial ones?


I made them.


----------

