[Housteau]

I just ran across these posted on the Bound For Sound web site http://www.boundforsound.com/CES_2007_pics.htm

This has the first photo showing the back of the V60 with the foam damper in place.  I had been curious about that.

[Brian Cheney]

Placement of the foam damper is one of the most interesting features of the V60.  As can be seen from the picture we ended up positioning the back of the damper flush with the back of the "V" which allowed plenty of rear output while absorbing all the reflections inside the wing. Of course the user has options ranging from "sealed back" to full dipole operation with damper removed, depending on room and taste.

The V60 is a reverse horn wide enough to prevent dipole effect cancellations down to 280Hz, the panel crossover frequency.  I don't think anyone has ever heard a good horn without the usual throat colorations, allowing the horn's enhanced directivity and energy bundling to be used to full advantage.  It's quite a sound.

There were cuts like the Wynton Marsalis Quartet with Diane Reeves (a redbook CDR from the NY Audio Society) that were extremely convincing.  The live sound in the studio could hardly have been more exciting.

This is what being an audiophile is all about.

[Vr3]

is that the Very Solid Subwoofer?

[Brian Cheney]

The picture shows a Larger sub in cherry converted to VSS specs.

The VSS (now in stock) is 30"W vs 32" for the Larger.  It is also about 30 lbs heavier, made of 2" MDF throughout with an internal window brace.  It's Very Solid.

[ka7niq]

Wow!
Those amps look like Atmosphere OTL's like they use on Soundlabs and 16 ohm Rogers LS 3/5 A's ?

Is the big new VMPS  a high impedance speaker ?

[Ryan45872]

Looks like a Larger with a plug.

[James Romeyn]

As most may know the 60 itself reproduces only above 70 Hz & can be driven by anywhere from 1 to 3 amps.  A sub is required below 70 Hz.

Midbass, 70 to 260 Hz: all 3 drivers are identical 8 Ohms ea; the 2 side drivers are seriesed for 16 Ohms, then paralleled w/ the front, for about 5.6 Ohms total; about 91 dB.

Mids, 260 Hz to about 5 kHz: Come in Brian?  Don't know, but moderate, between 4 to 8 Ohms; obviously 6 drivers provides many wiring options & Brian had his choice of lower & higher impedance versions of the mids; about 94 dB

Treble, above 5 kHz: 8 Ohms, true ribbon, transformer coupled, about 99 dB.

The Atmasphere barely needed a breath at any level, never heard the slightest hint of stress even with the German metal band at full tilt.

My Pathos Classic One Mk 3 in bridged mono was later auditioned powering one center 60 in a Trinaural rig (626R L-R).  Personally, take this with a huge grain of salt, & your results may vary wildly, I think even at the same prices (considering what it costs to retube a 200W Atmasphere & cool the room in the summer), I'd take the Pathos.  Brian's room is pretty big & heavily damped; even playing Roger West at high levels, no stress.  That's my future system.  

I highly recommend readers lusting after two 60s in stereo audition the above Trinaural system before plucking down the money.  Read the April Stereophile article re. 3-channel conversion systems.  Caveat: yes, I did notice, as per many other reports, the one weakness of Trinaural is in the event of phase shifts  in the stereo source.  Though the lyrics to Roger West's "Flight" were more clear on the VMPS Trinaural system than the several hundred thousand dollar YG Speaker System at CES (ditto TAD & Sound Lab megasystems), the weird phasey closing seconds had a collapsed soundfield vs. the intended wraparound effect.    

[ka7niq]

I was just curious when I saw the Atmosphere OTL amps if the RM 60's were configured for high impedance ?
This would be nice for SET folks, like those using amps single ended with 845 tubes in them ?

I am familiar with the Cyclotron amps, being from Michigan originally.
Electro Voice originally built them back in 1955.
I was one year old then, but I saw one at a Ham Fest in Michigan.
I could have bought it, cheap, stupid me.
I was "scared" of it, looked like a real contraption.

I have known people who owned Atmosphere OTL amps, and used them to great effect with mainly high impedance speakers.

I understand Atmosphere has a transformer one can use to better couple it to a low impedance load ?

Here is some info:

Given the benefits of the Circlotron: low source impedance, balanced operation and high common-mode rejection, it is possible to dispense with negative feedback altogether. The Atma-Sphere MA-1 is one product that does this. However, despite using 12 6AS7G's in a Circlotron output configuration, however, the damping factor is still too low for good compatibility with many of the lower impedance speakers available. Realizing this, Atma-Sphere offers a tapped auto-transformer to match the 11 ohm output impedance of the MA-1 to a one, two, three or four ohm load.

For many tube users, the concept of adding a transformer to the OTL topology defeats the whole purpose of the exercise - Sorry folks, if it needs a transformer to work properly, it ain't an OTL! It may still sound very good, and the auto-transformer design may be an improvement over other approaches, but it's not the holy grail. (Note: it may also be a lot more reliable than a pure OTL - an important consideration for anyone making these amplifiers for a living.)

I could care less myself if it is not the absolute holy grail, as long as it sounds good!

[ctviggen]

Placement of the foam damper is one of the most interesting features of the V60.  As can be seen from the picture we ended up positioning the back of the damper flush with the back of the "V" which allowed plenty of rear output while absorbing all the reflections inside the wing. Of course the user has options ranging from "sealed back" to full dipole operation with damper removed, depending on room and taste.

The damper is interesting, as most peoplry trying dipole operation don't put dampers in at all.  How does the damper actually get attached?

[PLMONROE]

A handful of Six Penny nails???   

[Brian Cheney]

The damper is made of foam stiff enough to support itself.  We now add an MDF base for more stability.  At CES we were forced to use Scotch tape to keep the foam from toppling, so a change was made in production.
There is also now a strip of 1" thick by 4" wide on either side of the apex of the "V" full length to kill the earliest reflections, so that the damper can be pulled back further from the panels when desired.

Reflections inside the horn throat (the Megaphone effect) are very destructive of linearity and naturalness, thus the damper.  I don't know of any other horn that uses such.