[audiochef]

We all have probably done the lambs wool insulation . And for the most part it is an improvement.
I've gone farther by adding the convoluted foam to line the midrange section with very possitive results.

Those mids have a hell of rear wave that needs to be absorbed . The mids are alot less bright now and lost the" brittleness" sound .

After the fix , the tweeter sounds too loud so you have to turn up the mids a few clicks. This won't ad more brightness , just more body . Vocal, especially is improved now. Throatyer for the male and less glary for saprano. Alot less.

As  for the tweater , I was never satisfied with sharp edge at the end of the opening of the horn. I used a needle file to round down the sharp edge evenly. This actually looks good too . It just looks silver highlited around the entire opening. The sound is sweeter , less confused , do to what I'm sure is decreased diffraction.

Overall I'm extremely pleased with this "upgrade".  There's clearly a wider sound stage do to less beaming of the mids. And the highs is a tiny version ,I think of  what dehorning does. Oh and the mids just seem to integrate better to the woofers. Really.
 

[john1970]

Audiochef,

Can you please provide more specifics for those of us who would like to do the tweak as well.  I own a pair of RM40s and would be interested in performing the tweek.  I assume you cut the foam to fit just behind each midrange panel, but I am not certain.  It would be much appreciated if you could:

1) Give the specifics on the foam (thickness and manufacturer)
2) Provide some detailed instructions.

Thank you and looking forward to performing the tweek on a rainy day.

Cheers,

John

[John Casler]

Another option to simple foam, is the a "multi-layered" barrier like that from Parts Express.

http://www.partsexpress.com/pe/showdetl.cfm?&DID=7&Partnumber=260-535

[audiochef]

John,
I use the super cheap yellow matress  foam you can get at Target. You  can cut them to any shape and size.  This is the stuff I'm still using in the main woofer cabinet as a "sonic barrier". I have real stuff, but haven't the time to install this yet, as I'm still satisfied with the cheap foam. Yeas the egg Crate foam from Parts Express will work to , but I'm sure to different effect cause it's stiffer and the poars are larger.

Good luck, Stan

[John Casler]

John,
I use the super cheap yellow matress  foam you can get at Target. You  can cut them to any shape and size.  This is the stuff I'm still using in the main woofer cabinet as a "sonic barrier". I have real stuff, but haven't the time to install this yet, as I'm still satisfied with the cheap foam. Yeas the egg Crate foam from Parts Express will work to , but I'm sure to different effect cause it's stiffer and the poars are larger.

Good luck, Stan

Hi Stan,

The Parts Express product is called "sonic barrier" and it has "layers" that affect more frequencies and damp a bit more than straight foam.  The limp vinyl layer is probably the biggest difference.

[BrunoB]

Audiochef,

Can you please provide more specifics for those of us who would like to do the tweak as well.  I own a pair of RM40s and would be interested in performing the tweek.  I assume you cut the foam to fit just behind each midrange panel, but I am not certain.  It would be much appreciated if you could:

1) Give the specifics on the foam (thickness and manufacturer)
2) Provide some detailed instructions.

The amount of stuffing (weight/panel) that was used is as  important to report as the type of material that was used.

Bruno

[audiochef]

The amount of matress foam I'm using is lined in the enclosure is on top, backs and above and below the tweaters.
All this was added a peice at a time. Listened ,and added again . Each addition made a differrence.

A word of caution to anyone wanting to File down or "flare" the opening of the tweater.  Be sure to tape over the screen first so you don't blow into and break the ribbon.

Stan

[BrunoB]

The amount of matress foam I'm using is lined in the enclosure is on top, backs and above and below the tweaters.

Stan,
sorry,  I don't completely understand your post. What do you mean with below and above the "tweaters"? is your speaker a RM40? Have you lined all internal walls of the enclosure with foam and then stuffed it with wool?

Have you weighted the amount of wool?

Thanks,

Bruno

[audiochef]

Hi Bruno,

I have original RM40s, two FSTs per speaker. I don't know if photos are still in the gallery or not.
The amount of wool I'm using is 1 pound per speaker, as weighed by Maddisound. I think Brian is using 1.5 lbs. per speaker from the factory.
Yes the enclosures are lined with matress pads in addition to the wool.

May I also add that for me I can turn up the mids even  a bit further now without fear of excessive brightness. A good good thing .

Stan

[BrunoB]

Hi Bruno,

I have original RM40s, two FSTs per speaker. I don't know if photos are still in the gallery or not.
The amount of wool I'm using is 1 pound per speaker, as weighed by Maddisound. I think Brian is using 1.5 lbs. per speaker from the factory.
Yes the enclosures are lined with matress pads in addition to the wool.

May I also add that for me I can turn up the mids even  a bit further now without fear of excessive brightness. A good good thing .

Stan

Hi Stan,

thanks for providing the details about the amount of wool you used. Sorry to have asked, but it is is very important for those who would like to reproduce your results.
Now if your are interested to decrease the midrange brightness even further, you can try my  CDWG-like  tweak on the midrange: http://www.audiocircle.com/index.php?topic=28349.0. My speakers sound much smoother with this tweak. I measured the FR of the midrange panel with the mic almost touching the panel: it was very flat (I don't have a pict). But when measuring from a distance of 50 cm, I can see the treble rising.http://www.audiocircle.com/index.php?action=gallery;area=browse;album=624&pos=0


Yes I remember seeing  the picture of your dual FST RM40 in the gallery. Impressive. Are your two FST connected in series or parallel?



Bruno

[audiochef]

Thanks for info Bruno,

I believe the tweeters are run parallel, Brian can correct this if I'm wrong.

Upon further listening, drums now have a more realistic "pop" , instead of a "snap "

Stan.