Great improvments to the 6.9SM

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KKM

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Great improvments to the 6.9SM
« on: 19 Jan 2004, 10:31 pm »
I've known for a while that the insides of the 6.9's had bare walls after seeing the innards replacing a blown tweeter. I knew almost all(if not all) speakers have some type of damping add-on regardless of design, why didn't these? While the drum design minimizes any type of standing wave and ugly diffraction, there probably still some unexplain interaction with the inert walls. There is a strip of egg crate foam on the inside edge of the face. It wasn't until yesterday that I had a chance to put some egg crate foam in there that I realized what I was missing. The difference was quite noticeable. The 6.9's were quite a speaker for the money and this small tweak  improved it quite a bit. The music was smoother and less harsh making the instruments more palpable instead of fuzzy. This was most obvious with solo acoustical instruments. The boundaries expanded, whereas before the speakers were more localized. Those were the most noticeable improvments to me, I'm sure there are more but I only made the tweak yesterday and only had a limited time to listen, its an easy tweak and was quite excited about the finding and wanted to share. I think that some better material could help improve it further like Black Hole or polyfill or even a combo.

MaxCast

Great improvments to the 6.9SM
« Reply #1 on: 20 Jan 2004, 01:11 pm »
Hi KKM,
Thanks for sharing this info.  How much did you put in and how did you get it in there?  Did you have to remove the baffle?  

I imagine you put a piece from one side of the xo up around to the other side of the xo??  Did you glue it?  How thick was the foam?

Also, did you read jackmans thread about possible xo upgrades?  Link

KKM

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Great improvments to the 6.9SM
« Reply #2 on: 21 Jan 2004, 05:34 am »
Maxcast, No Need to remove the baffle, just the woofer. I lined them up as you described without gluing it, just cut it a little larger so they fit snug. They covered most of the inside. I think that this is temporary, when I have time I'm going to try some other material. Not sure the thickness, typical eggcrate foam. I think those who own real marble as well as SM will benefit from some type of insulation. I did read about the Xover upgrade, some more tinkering later.

MaxCast

Great improvments to the 6.9SM
« Reply #3 on: 21 Jan 2004, 12:12 pm »
Thanks KKM.