[rbbert]

I was referring to the midrange and tweeter elements (I guess maybe a "modified" d'Appolito configuration?); the x-over to the woofers is low enough that I don't think that matters.

The V60 also has this configuration, I believe, but I don't see that model mentioned much?

[John Casler]

It is my understanding that in a true d'Appolito configuration the top and bottom drivers are identical. I don't believe this is true of any of the various RM-40 iterations.

Paul

Hi Paul,

Yes it is hard to qualify Big B's designs.

The most conventional might be the 626 or the RM2, but all in all he creates many hybrids in both shape, configuration and acoutical properties.

As I said the 626 is the basic Tweeter on top, Midrange and Woofer on the bottom.

Monopole

Rear Ported bass


The RM2 is the basic Tweeter on top, Midrange and Woofer on the bottom. 

Monopoles

Active and Passive Bass Drivers


The RM30 has an aspect of that same design with a 3 panel line sandwiched in.

Monopole

Active and Passive Bass Drivers


The RM40 also has a LINE theme with the tweeter sandwiched in

Monopole

Active Low and Midbass Actives Woofers and Passive Bass Driver


The RM v60 has a similar Line Theme with a folded wing open baffle

Dipolar Mids and Tweets

Three Active sealed Midwoofers (sub woofer required)


The RM 50 Bipole dual line array has a Dual Line Array of midpanels and tweeters on the front, and Single line on the rear firing Bipolar.

Low and Midwoofers are active, and a Passive Radiator.

So we have monopoles, dipoles, bipoles, lines, and standard elements in the designs.

As well since the MidRange drivers are Planars, they have some qualities of a point source (meaning that your ear only hears the panels at the same point in height)

All in all, no "pure" utilization of conventional designs, but more a functional hybrid employment to the goal of the designer.

From top to bottom lots of variety, but they ALL have that VMPS Sonic Signature.

[cliffy]

Hey!!

Don't forget my in-wall 626's which are sealed

[John Casler]

Hey!!

Don't forget my in-wall 626's which are sealed

Truth be known I left out several models, but the message is they all have a common sonic signature through the midband.

[krikor]

Recently got my hands on a pair of 626r and have been listening to them without the CDWGs for past month or two due to missing CDWG grille posts. Finally got those replaced and am now enjoying them with the CDWGs installed.

I've gone back and forth a couple times and gotta say at least initially I'm preferring them with the waveguides. Could be a couple of reasons:

• My OXO is setup for use with CDWG (at least I believe so) and not optimized for use without the guides, in which case I have to turn the tweeter/mid controls way down to get them sounding their best, though still not ideal in my opinion... would be interesting to try the D-OXO sometime if I can manage it with a proper setup for non-CDWG
  
  
• I'm a long-time Magnepan user which are not necessarily known for their dynamics, and so my listening preferences and expectations perhaps match up better with CDWG... I've read that many feel the CDWG restricts dynamics (though that's not my experience) and it could be that my tastes lean in this direction somewhat

Given these two caveats...

WITHOUT the CDWG, the sound doesn't seem as coherent from top to bottom... I have more of a sense that I'm listening to individual drivers, especially in the bass which strikes me as disjointed from the rest. Also I can't seem get the top end adjusted right, either too hot or too restricted, and I find myself wanting to change it more often as I listen to different recordings.

WITH the CDWG everything comes together and is much more enjoyable... don't find myself fidgeting and readjusting the speakers. Soundstage seems deeper and vocals more natural (no excessive sharpness/sibilance which bothers me without the CDWGs). Tonally, they just sound right with the waveguides.

[Roc]

I should log on more often!

I've been experimenting with wave guides for many months now.
Big John is getting tired of my late night calls to review the results.
As many are saying, using the guides improves focus, separation, and makes a rock solid image.
But there are the issues of trebble roll off, and a general muffled sound.

With the guides off the music opens up and is far more relaxed.  More linear freq. response, etc.
But focus and separation go down a big step.

I'm finding that the issue centers around baffle reflections.
Others can offer mathematical reasons, but the CDWG makes the baffle relfections go away.  Entirely! Like magic.
If your room doesn't have acoustic foam or diffusers on the side walls you will not notice this..mine does...I do.
The baffle reflections are causing phantom images inboard and outboard of the drivers.
This kills focus, and clarity.

I've tried countless methods to kill the reflections, foam, diffusors, and most recently reflectors.
I'm having the most success with reflectors, placed adjacent to all the drivers.
I'm currently using $5 "noodles" (flotation devices) cut and placed on the baffles in a special way to eliminate/reflect away the baffle reflections.
I'm getting about 75% of the CDWG improvement, without the roll-off issue.

The entire problem could be eliminated, and I'll let Brian comment further, with an "elixer" shaped baffle.
Thus we could have our cake and eat it too.

Or, I could just shut up, buy Brian's latest CDWG's and write back later.
John, I need a quote.

Dave

[John Casler]

I should log on more often!

For sure. . . Where you been?

I've been experimenting with wave guides for many months now.
Big John is getting tired of my late night calls to review the results.

Dave you know we are tweaking brothers by different mothers   

As many are saying, using the guides improves focus, separation, and makes a rock solid image.
But there are the issues of trebble roll off, and a general muffled sound.

With the guides off the music opens up and is far more relaxed.  More linear freq. response, etc.
But focus and separation go down a big step.

I'm finding that the issue centers around baffle reflections.
Others can offer mathematical reasons, but the CDWG makes the baffle relfections go away.  Entirely! Like magic.
If your room doesn't have acoustic foam or diffusers on the side walls you will not notice this..mine does...I do.
The baffle reflections are causing phantom images inboard and outboard of the drivers.
This kills focus, and clarity.

I've tried countless methods to kill the reflections, foam, diffusors, and most recently reflectors.
I'm having the most success with reflectors, placed adjacent to all the drivers.
I'm currently using $5 "noodles" (flotation devices) cut and placed on the baffles in a special way to eliminate/reflect away the baffle reflections.
I'm getting about 75% of the CDWG improvement, without the roll-off issue.

The entire problem could be eliminated, and I'll let Brian comment further, with an "elixer" shaped baffle.
Thus we could have our cake and eat it too.

Or, I could just shut up, buy Brian's latest CDWG's and write back later.
John, I need a quote.

Dave

Hmmmm a quote for the day? 

A stitch in time, saves nine?

Which really means buying a pair of RM50s today will save you from buying them tomorrow.

Just think, with the RM50's you could experiment with the rear firing dipole bank of drivers.  Direct reflected, diffused, or damped

[Brian Cheney]

Well, it's time to announce the new generation of Constant Directivity Wave Guides, as defined by our US Patent.

As indicated previously, the new guides are simple add ons that attach directly to the mid and tweeter panels.  They are lightweight, lack baffles, are inexpensive, eliminate treble rolloff, exhibit less than 1dB insertion loss,  and may be used with planar drivers other than our own, such as DG Neo 8 and Neo 10, Hi-Vi, and EMIM's.

Beyond improving directivity, I find the new CDWG's positively influence sound quality in other ways, such as midrange smoothness, bass solidity (we just shipped a pair of RM40 to England with the new guides, and their bass sounded like the RM 50's for both extension and impact), naturalness, and of course, dispersion. 

All this for $20/pair including shipping (intro price, one pair required per driver).

Pix to follow!!

[mjosef]

Wow, talk about cheap and cheerful...
Would I need two sets? I got RM1s and 626R. Or can I use the same set for both?

[Doug Ravizza]

one pair required per driver

So Brian, does this mean that 10 pairs would be required for the RM40s?

[BobMajor]

If used with an older pair of 626Rs does the tweeter have to be de-horned?

[Brian Cheney]

Any single panel pair of speakers requires two pair of waveguides, $40 delivered.  If you have the spiral ribbons and want to improve their directivity, a pair of tweeter waveguides is $16 delivered, one pair required per tweeter.

I tried to make the second generation CDWG as cheap as possible, to encourage all owners to get them.  I paid $300 just for the tooling on the foam parts (there is a plastic part as well, and the two are sandwiched together), so DIY should be futile, futile I tell you!  The CDWG attaches with spray glue, which the user supplies.  I tried many other attachments, but Scotch 77 or similar (about $6 for a small can at any hardware store) works best.

Most FST's have a slotted masks already and don't require the tweeter waveguides, but we do have semicircular antidiffraction masks available for dehorned tweeters for $16pr shipped, one pair required per tweeter.

[Pez]

can't wait to see those pics! Any xover changes necessary to make these things work better?

[Roc]

John,
I've haven't listened to the RM50's yet.  Hope to do that some day soon.

The custom passive radiator chamber I designed and installed on my RM40's allows me to direct the PR energy to one side, or all sides of the room, simply by unplugging some or all of the chamber openings on that side.
Allowing the PR to fire partially into the front wall really opens up the sound stage.
Allowing the PR to simultaneously fire into the side wall greatly improved bass response.
Restricting the PR from firing directly at the listener improves clarity.

With my chamber it may not be necessary to have rear firing drivers ???
But I don't have a comparison yet.

Can't wait to get a set of Brian's new CDWG's.  I'll call you tonight.

Roc

[underdawg]

Cant wait to see those pics also.