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PostPosted: Sun Jan 29, 2017 4:39 pm 
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Location: 53˚27'46"N 2˚17'28"W
Kawi, there are a few ways to do bass traps:

Tube traps. Tall, cylindrical; but of a challenge to construct.

Super chunks. Cutting the material into triangles and stacking into the corner.

Panel Traps. With these typical 4x2 traps they are usually straddled across the corners.

With your room, thinking that you have full autonomy over the decor, I'd suggest to make eight ceiling-height panels and butt up two together into each of the four upright corners of the room. This yields a greater surface area for absorption compared to chunks and a straddled panel. At the very least make four and straddle them across the same corners. The thicker you can make them the better.

An all-out assault would be super chunks with a panel either side 8)

These traps don't need to exclusive to only the upright corners of the room. The floor/wall junctions can also be treated also, though this is less visually appealing.

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PostPosted: Sun Jan 29, 2017 5:17 pm 
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Location: Ottawa, ON, CA
kawihornet wrote:
Here is the room layout


I recently adjusted my sub-woofer position due to poorly sounding bass. There was that 80 Hz hump, the whole room was vibrating. (after I built bass traps - which did help a bit, but not much), finally had to rearrange positioning of bass source buy moving sub woofer around until I found proper position in the room. It is only then that your bass traps will really help.

If you couch is positioned like it is displayed on your drawing, it should go closer to the speakers about 2/3 from the speaker's wall. (position on the back wall is not good - bass get overloaded/muddy)

Also, I would consider using a sub woofer (not sure if you have one), cross over your mains at 80 Hz, and than position sub woofer elsewhere in the room where the room mode is at its lowest interference so your bass will sound good.

Bass traps will help you somewhat, but will not solve your root cause problem - room mode - which could be addressed only with the proper bass source positioning within the room.

here is the link - very interesting read on bass management.

http://www.soundoctor.com/whitepapers/subs.htm

Good luck and let us know hos did it go.

Happy Listening


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PostPosted: Sun Jan 29, 2017 9:34 pm 
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Location: London, ON, CA
I recently added drapes to either side of my screen, with home made bass traps behind them. I have removed the drape from the left side. My speakers are in a 24" deep cove.

Image


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PostPosted: Mon Jan 30, 2017 7:56 am 
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kawihornet wrote:
Here is the room layout


you can solve most of your bass issues by moving the couch 4 feet forward

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PostPosted: Mon Jan 30, 2017 8:03 am 
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planetofsound wrote:
kawihornet wrote:
Here is the room layout


you can solve most of your bass issues by moving the couch 4 feet forward


+1 I really think the main problem is the interaction of the speakers with room modes and the placement of that couch on the back wall. Move the speakers and couch until you are satisfied with the tonal balance from the main listening position.


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PostPosted: Mon Jan 30, 2017 8:27 am 
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L-Man wrote:
planetofsound wrote:
kawihornet wrote:
Here is the room layout


you can solve most of your bass issues by moving the couch 4 feet forward


+1 I really think the main problem is the interaction of the speakers with room modes and the placement of that couch on the back wall. Move the speakers and couch until you are satisfied with the tonal balance from the main listening position.


you can easily tell by playing a 40, 60 and 80 hz tone and just walking around the room. you'll hear places where you have twice as much and half as much bass. put your couch where all 3 even out the best. bass traps will do almost nothing in this room. it's the dimension of the room that controls those frequencies.

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PostPosted: Mon Jan 30, 2017 8:31 am 
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Location: London, ON, CA
planetofsound wrote:
L-Man wrote:
planetofsound wrote:

you can solve most of your bass issues by moving the couch 4 feet forward


+1 I really think the main problem is the interaction of the speakers with room modes and the placement of that couch on the back wall. Move the speakers and couch until you are satisfied with the tonal balance from the main listening position.


you can easily tell by playing a 40, 60 and 80 hz tone and just walking around the room. you'll hear places where you have twice as much and half as much bass. put your couch where all 3 even out the best. bass traps will do almost nothing in this room. it's the dimension of the room that controls those frequencies.


Seems to me you're suggesting it's the position of the couch :D


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PostPosted: Mon Jan 30, 2017 8:49 am 
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One can move the couch out of the nodes, but if the energy remains in the room as long term resonant structure -there will still be interference and retardation of the sound qualities.

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PostPosted: Mon Jan 30, 2017 9:02 am 
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Your issue is most likely modal - a peak at one frequency and a suckout nearby created by the interaction with the room. Best way to fix is with eq, rather than broadband absorption.
Measure first - a Radio Shack meter with a test disc will give you a fairly good picture of the amplitude issue. You want bass below 100 to be a flat response but about 3-4 db louder than the range above.


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PostPosted: Mon Jan 30, 2017 9:19 am 
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Have a look at some of the products from Vicoustic - don't know if there any dealers in your area but I do note that there is a new Canadian distributor (in Montreal) so that may make getting access to the product much more simple.
In any event - check out the Vicoustic web site. There's a lot of product there and I have it on good authority from some major gear manufacturers that they use the product in their shows and showrooms almost exclusively.

justathought

jac

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PostPosted: Fri Feb 17, 2017 10:52 am 
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Location: newmarket, ON, CA
I had a problem with bass and highs so I hung a comforter in corners where system wall is. magic
It balanced everything out and improved the mirror imaging also.total cost 0 $. Before you blow cash on magic cables etc. Room acoustics do everything.


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PostPosted: Fri Feb 17, 2017 11:58 am 
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You mention you built a smaller room within a larger one. (basement?) Low frequencies have very long wavelengths and consequently, they can go right through drywall and most other walls. Only concrete or cinder block walls reflect all of the sound wave.

Based on the sketch and photo, I notice your loudspeakers are much too close to the cornered walls and thus are receiving way too much low bass reinforcement. To minimize nodal interaction, try coming out 1/3 of the total room length. If this is too intrusive then try 1/5 of the room length as a starting point. You should reach an optimum placement within a few inches of this point in either case. Even multiples of the room dimensions would exacerbate the situation.

Also space out the loudspeakers from each other as much as possible. (until there is a poor central image).

Partially blocking the ports can reduce low bass response as well.

Finally, you can build tube traps with rigid fiber-glass pipe insulators. They come in various diameters and thickness and should be filled with 'rock wool'. A one inch mdf or plywood bass serves nicely and are cheap to make. I built two 3 footers by 16 inch diameter for under $300.00. You can build 6 footers just as easily as the fibreglass interlocks making them stackable. Determine first if the bass nodes are in the upper or lower half of the space. Placing the tube traps in the corners does not always work best. I have mind just behind and slightly outboard of my speakers for best results as they are rear ported.

Edited by Mod team to conform to CAM Rules.

Just make sure you know the exact problematic frequencies before you start. Bass sweeps are available and are easily downloaded on-line. I burned a CD which I use when I am setting up loudspeakers at an audition and the sweeps are very useful for this process as you can repeat any frequency indefinitely while you move the loudspeakers into optimum position.

Good luck.

Jon@FoldBack Sound


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