Ascend modding experience

[BradJudy]

While I was modding my X-LS's, I decided to use the No-rez dampening material (similar to Blackhole 5) on my CBM-170SE's instead since they have thinner cabinet walls. So, I proceeded to disassemble my CBM-170s to install the no-rez. I made one mistake - when removing the quick connects from the tweeter, I didn't notice the notched hole holding it in and pulled the whole ounting tab off of my tweeter. One ruined tweeter, a call to Ascend for a new one, a few bucks out of my bank account (stupidity tax), a few days for shipping, and I'm back in business.

Since I had already ruined the tweeter I completed the no-rez install on one speaker while waiting for the new tweeter. I removed the poly batting glied to the sides and cut no-rez to fit the sides, top, back and bottom (the back and bottom were multiple smaller slices to get around the crossover/port/binding post cup). I reassembled the speakers and installed my replacement tweeter today.

I intentionally only did one speaker first to try and compare. I'd have to to some special work to really compare (make audio files/CDs with the same content on both channels), but so far I'm not certain if there's an audible improvement. If I touch the cabinets while their playing, I can't say there's a noticable difference in how much they vibrate (since the change in mass isn't significant, this isn't really surprising).

I'll listen some more before doing the other one before passing final judgement, but right now I'm not certain if I could tell you which was the treated one if you blindfolded me.

[Quinn]

Is NoRez a glue in product or can you move it? It would be interesting to put a sheet in one of the other speakers and see if it does anything for those.

[curtis]

someone correct me if I am wrong, but doesn't the poly batting/fill also serve to slow down air movement within the enclosure?

When I was making the car sub with the Hsu driver, I was told that one of the reasons of the polyfill was for that, which in turn makes the enclosure "act" a bit bigger.

Maybe DaveF will chime in....I have a feeling he has tried different things inside of speakers. :)

[BradJudy]

I didn't remove the polyfill batting. Inside the 170s there is loose polyfill that fills most of the cavity and then a layer of batting glued to the sides. I removed this layer around the sides and replaced it with No-rez. I then put the loose polyfill back in.

No-rez is not loose since that would defeat the point - it adheres to the walls.

[curtis]

oh...OK. :)

[GirgleMirt]

I thought the same thing as Curtis about adding the stuff..

http://www.gr-research.com/components/blackhole_5.htm

Whatever exactly the stuff is... My guess is that it will change the enclosure's internal volume. I've also read that polyfill makes the enclosure act if it was bigger, so that might counterbalance a bit... But my guess would be that as the internal volume has changed, it will have some effect on the speaker's FR (though probably something small... nothing drastic as I guess the volume change wouldn't be dramatic anyhow)

About damping... :confused: Is it like very heavy/thick/rigid stuff? How thick is the MDF used in the 170/340 btw? 3/4 inch?

Sucks to hear about the tweeter :o

[BradJudy]

It's realtively heavy stuff, similar to dynamat with foam on top.

The CBM-170 spec sheet says 5/8" MDF. I think DaveF said he intentionally did not go with thicker walls, but I don't recall the reasoning.

I thought folks might be more interested in the experience, but the trend seems to be saying why it's a bad idea. Oh well.

[GirgleMirt]

Well if there's no audible change, besides the destroyed tweeter, no harm done :p

From my very limited knowledge of speaker building, putting some filling or not seems to be part of the design of the speakers. Some use some, others don't use any filling at all... I really couldn't tell you the plus or minus of both, but I remember some people attributing to the filling some character of 'boxyness'... as if it had some impact on the sound "coming from boxes".... Never experimented with it as I've only done a sealed sub... For the sub, the bigger the cabinet, the lower the response, for ported speakers, maybe its the same, less internal volume = little less lower response... But again, its a change of what % for internal volume? 2% maybe? Then maybe again it makes the cabinet act as a little bigger, so maybe that counteracts and you're left with the same, or maybe it makes the cabinet a little bigger and you get a slightly deeper response...

I guess the damping can't be bad but my 340SE seemed pretty heavy, I didn't do the tap test, but they seemed pretty solid (well braced), was there some braces on the top/side?

[Quinn]

Partsexpress has similiar stuff at about half the price. http://www.partsexpress.com/pe/showdetl.cfm?&DID=7&Partnumber=260-535

[curtis]

I thought folks might be more interested in the experience, but the trend seems to be saying why it's a bad idea. Oh well.
I am very interested. I just didn't have a clear understanding of what you did.

[bikeman]

I am very interested. I just didn't have a clear understanding of what you did.
I'm also very interested in this experiment. Thanks for taking the time and expense to do it. I'd be interested in Dave F's thoughts on this but he seems a bit occupied at the moment. ;)

David

[BradJudy]

I am very interested. I just didn't have a clear understanding of what you did.

I'll take a couple of pictures when I get the chance. Basically, there are two types of batting int he Ascends: typical polyfill wad and a piece of ~3/4" batting (like what you'd use when making a blanket) that goes around the two sides and the back, held in place with a few spots of hot glue.

I pulled all of the batting out, then cut pieces of No-rez to fit each side wall and stuck them in place (the adhesive on the no-rez seems quite good). I cut a piece to go on the 'ceiling' of the speaker and stuck it in place. Then I cut some pieces to fit along the back wall around the port and bind post cup/crossover and stuck them to the back. Then a couple of pieces to fit on the bottom and stuck them down. Lastly, I put the polyfill wad back in the speaker and screwed the drivers back in.

Net result: ~half a sheet of no-rez in the speaker and a ~1'x2' piece of 3/4" batting out of the speaker.

[Jonnyozero3]

Hey, any updates on this? I'm curious as well....

:)