Opinions on possible RM-40 mod

Brian Cheney · « **Reply #20 on:** 15 Mar 2004, 04:02 pm »

I use a step impulse for time alignment, but the square wave thing should work well also.

Brian Cheney · « **Reply #21 on:** 15 Mar 2004, 04:02 pm »

I use a step impulse for time alignment, but the square wave thing should work well also.

audiochef · « **Reply #22 on:** 15 Mar 2004, 05:48 pm »

Bob,
thanks for detailing your findings of your mods. I've also ordered the wool.

What version Rm40s do you have and what does your system consist of?

Bob Wilcox · « **Reply #23 on:** 16 Mar 2004, 03:43 am »

Audiochef

My RM-40s have the standard tweeters, toggle switch and were purchased with Auricaps. These were bought around the time that the TRT option became available. Eventually, I bought the TRT mod and installed it.

The rest of the system:

Pioneer DV-47A modded by both Ric and Dan Wright. PS Audio HCA-2, Scott 350 tuner, GyroDec(desprung)/SME 309 Walker Signature Phono, eAR 2 mk I, ExactPower EP-15, Quantum Sympony Pro, PS Audio and Absolute Audio power cords, TRT interconnects and speaker cables. Lots of Mapleshade cones, 2 Samson racks.

Bob

Bob Wilcox · « **Reply #24 on:** 20 Mar 2004, 12:05 am »

I received the lambs wool. I did not get around to removing the nylon spacers previously. I removed them from one speaker and replaced the fiberglass with the lambs wool. I then played a mono track and played with the balance control. The speaker with the lambs wool sounded a bit more transparent. The speaker with the raised ribbons still sounded a bit quicker and threw a slightly wider image but was not as transparent.

I then modded the other speaker removing the spacers and replaceing the ribbon chamber insulation. In checking out out Amused to Death, the increased precision with the phase trickery was readily apparent. On one track, a phone rings to the right. With the raised ribbons, this phone was at 180 degrees to my right. Now, it sounded as if it was coming from behind on the right.

The raised ribbons did have a certain charm. They reminded me of the electrosatic panels on Innersound Eros I used to own. I wonder if these panels were quicker than the Innersound woofers and this accounts for this similar impression...

BrunoB · « **Reply #25 on:** 20 Mar 2004, 12:44 pm »

Quote from: audiochef

Bob,
thanks for detailing your findings of your mods. I've also ordered the wool.

What version Rm40s do you have and what does your system consist of?

A practical question: where did you order the wool?

Thanks,

Bruno

Bob Wilcox · « **Reply #26 on:** 20 Mar 2004, 01:21 pm »

Bruno

The wool is $9.50/lb plus shipping. Order info:

http://www.madisound.com/order.html

Bob

zybar · « **Reply #27 on:** 20 Mar 2004, 04:45 pm »

I never got around to posting a few pics I took while changing to the wool.

So here they are (sorry I accidentally deleted the ones that showed the cavity with the wool):

George

ekovalsky · « **Reply #28 on:** 20 Mar 2004, 04:51 pm »

How much wool did you order for the RM-40's? I'd probably need 50% more since the RM/X has six rather than four neo panels.

zybar · « **Reply #29 on:** 20 Mar 2004, 04:55 pm »

Eric,

I went overboard and order 4 lbs.

I used half of it and the area is stuffed pretty well (but not over stuffed).

To be safe, I would order 5 or 6 lbs. With a cost of $9/lb, ordering an extra pound to be safe isn't exactly breaking the bank.

It really will make a noticeable improvement.

George

Marbles · « **Reply #30 on:** 24 Mar 2004, 01:25 am »

I just received and installed my wool.

I can't remember spending better money.

I hate using old cliche's, but it won't stop me. Before it was like looking through a clear window to the music, now it is as if the window was thrown wide open.

Highly recommended tweak.

zybar · « **Reply #31 on:** 24 Mar 2004, 01:28 am »

Rob,

How much wool did you use inside each 40? I assume you also did the RM 30?

We should all thank Ric for such a great and cheap improvement!!

George

JoshK · « **Reply #32 on:** 24 Mar 2004, 01:29 am »

Where did you guys get your wool?

zybar · « **Reply #33 on:** 24 Mar 2004, 01:30 am »

www.madisound.com

I think it is $9.99/lb.

George

Marbles · « **Reply #34 on:** 24 Mar 2004, 01:41 am »

It's hard to tell how much I used because it was packed into the box so tight. I bought 4 LB's because I wanted to do all my speakers and I had about a 1/2 LB on hand.

I think I used about 60% of the 4 LB's, but that is a guess.

I have not done the 30 yet, but maybe tomorrow night.

Tonight I will be to busy listening to new vinyl.

THANKS RIC

zybar · « **Reply #35 on:** 24 Mar 2004, 01:46 am »

That's about the same amount I used in my 40's.

When I was changing the stuffing I was a little unsure how tightly to pack things. Ric said pack it well, but not too tight.

That translated into using close to a 1lb in each speaker.

Amazing how much of adifference it makes. Brian really should think about switching or at least making it an option.

I haven't heard of anybody who has tried the wool and not thought it was a significant improvement.

George

jgubman · « **Reply #36 on:** 24 Mar 2004, 01:47 am »

How much wool are you guys stuffing into the midrange compartment?

Isn't the amount of dampening material a tuning variable? Could some of the effects you're hearing be due to over/under stuffing or is dampening mainly just a tuning variable in bass enclosures?

zybar · « **Reply #37 on:** 24 Mar 2004, 01:50 am »

See above...

Close to a 1lb per speaker.

George

Marbles · « **Reply #38 on:** 24 Mar 2004, 02:22 am »

Quote from: jgubman

How much wool are you guys stuffing into the midrange compartment?

Isn't the amount of dampening material a tuning variable? Could some of the effects you're hearing be due to over/under stuffing or is dampening mainly just a tuning variable in bass enclosures?

I would say that the fiberglass is reflecting the soundwaves back through the midrange panels and the lambswool absorbs them so they don't come back through. This is just a guess, but it is the guess on why things are cleaner sounding. More air around sounds and imaging is better.

Maybe the AMOUNT is a tuneable variable, but it is most probably the absorptive/reflective properties that matter more in this case, unless taken to extremes on either end.

As for should this be an option, no I think BC should include this on every speaker with a midrange panel and kick up the price (plus profit margin) to account for it.

Theirs only $20 worth of wool in the pair of 40's and so maybe he should charge $30 more. For the benifit you get, it's a no brainer.

It won't matter to me though, I've got all the VMPS speakers I will have for a very long time.

Brian Cheney · « **Reply #39 on:** 24 Mar 2004, 02:33 am »

As I have pointed out in the past, wool is not reactive enough for lowbass damping but could be just the ticket for mids where the cutoff is around 160Hz.

I'll order some from Madisound and report on any changes.