Desktop Speakers - how to remove resonance in the desk, decouple ?

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Super Hans

Hi all, I have a pair of CBM-170 speakers next to my monitor.
I am using a couple 8"x 8"x 8" painted concrete blocks as stands.
Using garden hose washers between the speakers/blocks and blocks/desk.
It's just a regular MDF desk.

So, I can definitely feel and think I hear resonance in the desk.
Kind of unavoidable to a degree I figure.

My question is, would gluing some acoustic material to the bottom of the desk absorb much of the resonance ?
Anything better than washers for fairly cheap that would help with resonance, decouple speakers from desk ?
Acoustic foam between speakers/stands and stands/desk, Sorbothane Feet/Pads, etc ... ?

Thank You
« Last Edit: 2 Apr 2018, 11:54 pm by Super Hans »

mresseguie

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Hello, Hans.

The desktop I'm typing on right now is an Ikea plywood board. It's a no frills design with metal tube legs and an underside support bracket of the same metal. It resonates like crazy.  :duh:

In the beginning I tried using commercially available foam monitor supports (Auralex) that cost something like $45. These helped in that the speakers were angled up toward my face rather than being flat on the desk and the foam absorbed some of the resonances. I thought I had it pretty good until I discovered that I could get the same thing from my local foam seller for $5(!). That's right. Whomever owns Auralex is making close to 1000% profit on cheap foam. The sole difference was that the cheap supports didn't have the snazzy looking plastic label.  :duh: [Lots of head slapping here.]

Just last year I finally shelled out $110 (I think) for a pair of IsoAcoustics monitor stands that really did an impressive job of improving the sound. These are adjustable height supports. Someone on AC had tried them and enthusiastically posted about them. He was smack on with his impressions. These are definitely worth the investment IMO. Sure, my desktop still resonates, but it is much better now thanks to the IsoAcoustics stands.

More than likely, I will replace my desktop with a much thicker wood slab top that weights a hundred or more pounds, but resonates only a wee bit. Hopefully, I'll do this in the Fall or Winter of this year.

Hope this helps you.

Michael

Super Hans

Hi, very helpful.

I ordered a pair of the foam monitor supports off Aliexpress (US store) for $9
Look exactly like the Auralex ones without a label on them. 
Yea I saw that too. $50 for the Auralex ones.

Glad to hear your feedback on the IsoAcoustic stands.
I read a few reviews and noticed a few people said they are sturdier than they look.
Just might have to get a pair of them.

thanks for the reply 





zoom25

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I have Isoacoustics stands for my Amphions and have used them in both long and short configurations. Try filling the pipes with sand. It provided an improvement for me. I use kitty litter. It cost me less than $5 for a more than big enough box. Should be available ay any grocery store or home depot etc.

mresseguie

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"thanks for the reply"

You're welcome.

I remembered another tweak that I tried (and really like) with my stand mounted Fritz LS-5/R two-way monitors that helped with my living room floor's resonance issues. Ikea sells bamboo cutting boards. I bought the largest ones last year (don't know if they still sell them). There were a few different sizes. Then, I went to a home improvement store called B&Q (similar to HD) and bought two carpet squares.  :scratch: I'm not sure what to call them, but I'll try. Each square is approximately 15" each side. It's like indoor/outdoor carpet. The backside is sticky/tacky enabling you to lay down as many squares as you need without using additional glue or adhesives yet not so tacky that you can't remove them in the future. I cut each square to the size of each bamboo cutting board. Then, I flipped the carpet rectangles upside down, so the carpet is facing my wood floor. I set the cutting board onto the tacky side. [This allows me to slide my speakers out to more optimal placement when my wife is out of the house without scratching the floor.]

Onto the cutting board I placed my spiked four post speaker stands. My speakers are on the stand plates - currently with the Auralex pads, but I want to try other feet. My bass improved a lot. It's much cleaner now.

I know my example is used on my floor, but you could easily use this method on your desktop underneath your concrete blocks. Add some sort of spikes/feet to separate the concrete blocks from the bamboo cutting boards. If it fails to achieve your goals, you can return the bamboo cutting boards for a full refund.

Michael

P.S. Nice link.  :thumb:

A_shah

Worth investing in Isoacoustic stands I use them with Audioengine HD6 powered speakers on a dresser in the Bedroom with my flat panel  TV the SQ improved and got rid of most resonance  previously tested them on my Desk with Kef LS 50 but took up too much real estate so I put the KEf on stands and shifted the IsoAcoustics to the Bedroom Dresser

JLM

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Have a nice desk (5 foot wide with a very heavy top), CBM-170s, and Iso-stands (that came with my Dynaudio BM5 MkIII's) that I've never taken out of the boxes.  I only listen in-room, not headphones, not desktop (am spoiled but ready with my iMac on the desk and am using the CBM-170s in my AV system).

Desktop listening is fraught with excessive bass reinforcement, bounce back off the desktop, and resonances (made worse from light weight speakers).  Getting the monitors off the desktop (ala stands) help with the bounce back and excessive bass plus gets the speakers closer to ear height.  Adding a bag of lead shot on top of the monitors helps with the resonances.  Iso-stands would help achieve better tilt angle and with the resonance too.  Any other resonance fix is a crap shoot of trying to find the right compliance (springiness) for the given weight (one for the speaker, another for the speaker plus heavy stand) to provide better isolation.  IMO the garden hose washers would be way too stiff to help. 

Suggest looking at what studio professionals use. 

Super Hans

yep, the washers are way too stiff.
I'm going to try the foam monitor supports on top of the concrete blocks.
Just have washers under the blocks to protect the desk I guess.

Nice to know you can fill the Iso stands.
Sounding better and better.
And they don't look like a dorm room setup.
(I did prime/paint, and seal them so they actually don't look too bad for concrete blocks)