[Doug Ravizza]

I much prefer the sound of my RM30 IIs with the grills removed. Having recently added a front projection system to my listening room, I was concerned about the potential for back reflections from the shiny acrylic parts of the waveguides. I found some 2-1/2" wide black velvet ribbon at a local crafts store, cut pieces to size and attached them to the acrylic parts with double sided tape. This eliminated back reflections and improved, IMO, the waveguides' visual appearance. To my ears, there was no perceivable impact on audio quality.

I realize this is a very minor point but I liked the result and wanted to share. The first photo was taken with a flash with the camera directly facing the speaker and you can see no back reflections from the waveguides.

-Doug

[underdawg]

nicely done, it does look better imho.

[Ric Schultz]

Some have reported that they still like the midrange better overall without the latest waveguide.  Here is what I would try: Replace the entire waveguide with a thin piece of felt with the exact same dimensions.  This way you still have some limiting of the highs to the center but less loss overall.  I would bet most would like it better.  The "hard" part of the waveguide appears to be restricting too much of the energy from the driver.  The thin felt would let some energy through where it is and let all through where it is not.  Try it.....it is cheap.  You might have to fiddle with the mid/tweet controls slightly to get it to where you want.

By the way, the mid and tweet controls that Brian used are simply wretched.  They are cheap Chinese L-pads which should be resticted to midfi or lower usage.  There are no other high end speakers that I know of that use cheap L-pads.....and for good reason.....they sound bad.  Many people like the fact that you can "tune" the speaker to different rooms and equipment and that is a nice feature for sure.......but it comes with tremendous loss of clarity and reality.  I want both (correct frequency response and all out transparency).  It is best to use fixed resistors of super high quality (Dueland, Caddocks bypassed by Nude Vishay).  The difference is tremendous.  You can use one resistor before the xover parts instead of an L-pad after the xover parts....but even substituting two resistors in the the exact position where the L-pad is would work fine.........but less parts is usually best.

[lowtech]

There are no other high end speakers that I know of that use cheap L-pads...

Do you consider Vandersteen speakers "high end"?  Just curious.

[John Casler]

Hi Rick,

The CDWGs are designed to create an acoustic lens, that due to the physics involved will create a greater dispersion of specific frequencies based on the width and position of the apature.

Acoustically this method will then, of course distribute the sound energy over a greater area.  This distribution will, again due to the laws of physics, reduce beaming, and increase directivity.  Anytime you disperse energy over a greater area it reduces it.  That is why, you cannot easily A-B CDWG's on, CDWGs off since you would need to boost the energy of the panels to accommodate for that increased dispersion.

Your "thin felt" suggestion would not operate in the same fashion as the physics would be much different.  All that would do is damp some of the higher frequencies, and have no acoustic lens/wave guide properties to speak of.

Applying felt and foam just outside the panels has been a favorite tweak of many, but not covering the driver, and not to improve directivity. 

I might also take issue with your assertion that the components Brian used were "wretched" and should not be used in a High End Speaker.  You are certainly entitled to your opinion, but it might be better received in another Circle other than the VMPS Circle where most of the owners know how good their speakers sound, L-Pads and all.

This may have been due to Brian's artistry which has held the test of time and been proven in hundreds of systems over the last 35 years or so.

[Doug Ravizza]

I might also take issue with your assertion that the components Brian used were "wretched" and should not be used in a High End Speaker.

John,

I also found that comment rather peculiar - why on earth would Brian, or anyone else for that matter, go to the trouble of offering pricey and labor intensive XO upgrades like hand trimmed caps (TRTs) and premium wiring and then use "wretched", bad sounding L-Pads?

Other than the "cosmetic tweak" described above, my 30s sound absolutely gorgeous just as they left the factory thank you very much.

-Doug