DCM Time Window

[restorer-john]

A redesigned X.O., wiring and tube connectors will lift performance to unseen heights

My Timewindow 1as actually had a type of tube connector for the bananas IIRC. Seriously.

Internet pic

 

[DavidMcRoy]

From what I’ve been able to determine, some of the CX-Series, the 17 (like mine,) the 27 and the 31 were coaxials. I have a CX-07 that isn’t.

 

[ZolaIII]

Yes, I agree. What would be modern, would be some of that light bleached ash style timber end caps and that white/grey/cream woven fabric like Ikea use on everything. Like this:

View attachment 215420

See if you can find Sorbus torminalis as a wood for the job (cabinets in generally) and of course not for the looks of it (but for density and properties).

 

[anmpr1]

From 1978 or '79.

 

[mhardy6647]

The last paragraph of that commentary above on the improved timewindow is quite remarkable (in a good way).

 

[amicusterrae]

The last paragraph of that commentary above on the improved timewindow is quite remarkable (in a good way).

Classic Peter Aczel and The Audio Critic!

 

[aslan7]

While looking into these I came across a really nice pair of CX-27s for next to nothing. They sound awfully good so I am in something of a quandary.

 

[DavidMcRoy]

While looking into these I came across a really nice pair of CX-27s for next to nothing. They sound awfully good so I am in something of a quandary.

The fact that the radiation geometry of the CX-Series is more like that of a ”conventional” cardioid pattern speaker than the Time Windows and early TimeFrames probably makes them a better choice if you’re going to use them in surround system (so I have found.) I have modified my Generation-1 “Time Windows (Improved)” pair to reduce the output of the “outboard” drivers by 3dB in keeping with what DCM said, in reference to the characteristics of newer versions of the Time Window, was preferable for tighter imaging at the expense of some soundstage width, so I can used them more successfully in my Dolby Atmos system. And they were right. As an added bonus, the CX-17, 27 and 31 use a coaxial driver arrangement (with the very sweet Visaton or Vifa tweeter) which further improves imaging coherence. So, I wouldn’t bat an eye about going with them unless you’re really jonesing for the original Time Window magic that comes from spreading all that mid to high-frequency joy toward the side walls and around the room.

 

[Mike_]

My Time Windows. Original owner. I separate them from the floor with Auralex MoPADs to keep more bass in my room (and away from my neighbor's apartment). As a young guy I worked in a speaker assembly factory - I hope I *never* have to service my Time Windows. That said, I love the sound. I hope they hold together for the rest of my life.

 

[normanj8129e]

I own the second pair of Model Ones built by my friend and co-designer, Steve Eberbach and other Ann Arbor friends in partial payment for designing the original versions. (The high power pie-shaped PA speakers of which only a few were ever produced.) The speakers and cross over of my pair were upgraded in 1998 and is still being used today with the original matching Mauer amp. The Time Window was our second design for the commercial market. The Model One has 4 pairs of matched speakers and tweeters in a "T" formation with three flat panels on the front and the cardboard barrel back. The Model One A is half this size. This speaker is the only commercial speaker that ever was able to recreate an acoustical square wave in a room. We did tests that proved the speaker had an essential zero-phase delay of all harmonics from 20 to 20khz hence, capable of forming an acoustical square wave about three meters in front of a pair spaced two meters apart.

 

[restorer-john]

This speaker is the only commercial speaker that ever was able to recreate an acoustical square wave in a room. We did tests that proved the speaker had an essential zero-phase delay of all harmonics from 20 to 20khz hence, capable of forming an acoustical square wave about three meters in front of a pair spaced two meters apart.

I remember all the talk about phase being excellent with the Timewindows themselves. With the two pairs I had, 1 and 1as, I found that to be not true at all.

Being as you have a pair of Model ones (a different speaker of course), can you demonstrate the method and show this square wave? And show us a few pics of this interesting speaker you have.

Cheers.

 

[dlaloum]

I remember all the talk about phase being excellent with the Timewindows themselves. With the two pairs I had, 1 and 1as, I found that to be not true at all.

Being as you have a pair of Model ones (a different speaker of course), can you demonstrate the method and show this square wave? And show us a few pics of this interesting speaker you have.

Cheers.

As I recall - Quad made that claim with the ESL63?

 

[normanj8129e]

The test was done in Eberbachs basement acoustic chamber when we were doing the initial development work. We took pictures of the osciloscope trace and used it on one of the first Time Window brochures. Of course, the mic has to be carefully placed at the centerline and the speakers loaded into an acoustic chamber so there are no echoes to speak of. The square wave recorded was indeed a square looking wave so I estimate the distortion at around 5 to 10%. Compared to other speakers at the time, 30% was the going level of phase linearity and distortion. These speakers are the closest thing to headphones possible. I'll post pics later.

 

[anmpr1]

We took pictures of the osciloscope trace and used it on one of the first Time Window brochures.

 

[restorer-john]

As I recall - Quad made that claim with the ESL63?

You are totally correct there.

I think I have some early 'oscillograms' of the Quad ESL63 doing square waves.

There was a lot of hype with the DCM Timewindow. Much of it due to clever advertising and a few 'rave' reviews. Some of it deserved, most not. Having owned TWs, they are more flawed than not, but very interesting speakers, nonetheless.

 

[restorer-john]

The TWs were extensively reviewed by the highly respected Louis Challis in ETI, January 1981 here in Australia.

I've made a PDF if anyone is interested (attached)

These no doubt were the units 'featuring' the horrible and cheap Philips plastic dome tweeter which they carried into the 1a before upgrading the 1a to the Vifa D19 tweeters.

 

[Mike_]

The TWs were extensively reviewed by the highly respected Louis Challis in ETI, January 1981 here in Australia.

I've made a PDF if anyone is interested (attached)

These no doubt were the units 'featuring' the horrible and cheap Philips plastic dome tweeter which they carried into the 1a before upgrading the 1a to the Vifa D19 tweeters.

I've downloaded the pdf for my reading enjoyment. I'm also enjoying the back-and-forth between participants. It's telling a story, and I hope there's more to tell. I'll throw in if there's any interest; as I mentioned above, I own an original pair. I haven't modified them in any way. Assuming they're in good working order, and anyone wants to bother, I'll allow them to be tested here in Madison Wisconsin. I read that the UW School of Engineering has an anechoic chamber. Supposing - and this is a big supposition - that they'd allow us to perform tests there, I'll allow my Time Window loudspeakers to be evaluated there. Stipulation: my loudspeakers have to be returned to me in good working order.

 

[anmpr1]

Aczel gave the various TW good reviews. It was the first I'd heard of the brand. Peter was a proponent of drivers wired 'in phase'. In his opinion, that would result in reproducing pulses more accurately, all things being equal, thus resulting in a better sounding loudspeaker.

I think for him the idea came from (I'm guessing) his time with the Rectilinear Research, and his association with computer engineer Bruce Zayde, the latter responsible for the design of Fourier loudspeakers. At least through the mid '80s, when that company closed up shop and Zayde went to Hewlett Packard.

By the time Peter resurrected his magazine, he had mostly abandoned that specific design criteria as being much of a concern, given other aspects of loudspeaker design parameters.

 

[mhardy6647]

I like 'em (original TWs, that is) -- even with the "horrible" (but widely employed, for many years) polycarbonate dome Philips tweeters.
Not that my opinion matters one whit, but I was taken by the TWs the first time I heard a pair, and still find them an enjoyable (and easy to drive) listen.

PS Thanks so much, @anmpr1 and @restorer-john, for your attachments! I have very little in the way of TW ephemera, so it's nice to see some more!

PPS I have this nigh-on irresistable urge, in the context of this thread, to mention Roy Allison and his original line of Allison loudspeakers, particularly the Allison One. Ooops, I guess I failed to resist it!

 

[fpitas]

Since no one has said it, I'll be the corpse at the party. Vintage speaker restorations are often a crap-shoot. The wrong year of driver may have been substituted, or in many cases a cheap generic driver that sort of looks like the original. Don't let me discourage you, but keep that in mind as you shop.