Using Dipole Speakers in a Stereo System
Mrmb, I decided not to try the felt; the egg crate design foam seemed to more closely resemble the material used in anachoic chambers that I've seen. Also, felt actually seems like a fairly hard material, now that I've looked at it, and it may be somewhat reflective of sound energy itself. Anyway, the design I'm using will be an attachment to the Odyssey cross brace holding the damping material approximately one foot behind the tranducer. I could easily be wrong in assuming this but, because of the curved design of Martin Logan panels, damping material closer to the speaker may work better. |
If the egg crate foam helps, you may consider something with more of a broadband acoustic effect. Several years ago, I built 2 DIY acoustic panels via Jon Risch's design perameters on AudioAsylum. My final floor standing-size products were 6'H x3'W x18"D. I'm still using them. But while researching these, folks mentioned that egg crate foam -- the type used as bed toppers -- although it looks like the foam used in studio's, it really wasn't, and didn't have the same acoustic properties. However, it certainly should give you the opportunity to learn (rather inexpensively), whether you're on the right sonic/acoustic track or not. FWIW, Soundlab sells an item called the "S.A.L.L.I.E". http://www.soundlab-speakers.com/#!__products/accessories S.A.L.L.I.E.'s are mainly for those who can't pull their stats very far out into the room. They're rather expensive, but perhaps one could produce a similar DIY device. I've also heard it mentioned that artifical floor standing plants behind dipoles also acoustically helps. |
Mrmb, thanks. The foam that I got, and I should have been more clear, is not the cream colored rubbery stuff that one puts on mattresses. It is acoustical foam (polyurethane or polypropylene?) sold specifically to reduce hard surface reflections. By most standards, though, especially materials made for commercial anachoic applications, it was quite cheap. A 4'x8' sheet was less than $80 of which I only used about half. Maybe now that I know it works I may look into trying some higher quality purpose designed material. |
That's good to know. You can also try doubling the thickness of egg style foam to see if it improves some more. I think a higher density absorbing material will ultimately be your solution for the Odysseys if you are looking for further improvements. Several materials have been presented here. On a separate note, what is the dB value of soft and loud volumes you are listening to? If you don't have an SPL, several apps can be downloaded for free. For me loud is 80dB or more, and the panels remain effective at minimizing the reflections. As you pointed out, the louder it gets the more effective the results. |
