Cogent
True-to-Life
Horn Loudspeaker
Development Project


Pictorial Essay

Los Angeles, California

June 4th, 2006


 

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During the Stereophile / Primedia-sponsored Home Entertainment Show in Los Angeles June 1st - 4th, 2006 we visited a couple of local installations, one of them the home of one of the Cogent True-to-Life team members, Steve Schell and Rich Drysdale. There they had set up a modest system, modest that is except for the fact that it featured the latest version of the Cogent True-to-Life horn speakers.

Here you see the heavily damped room in which the system is set up. The horns and subwoofer unit are using the same physical enclosures as that seen at CES 2006 in Las Vegas. System source equipment, speaker crossover, and the Cogent compression drivers are all different from that used in Las Vegas. The room is about the same depth, but not quite as wide.

During our very short visit, we got to hear those two LPs you see in the photo: Santana and Satchmo plays King Oliver, as well as a number of our test CDs including the latest manifestation of Pink Floyd's Dark Side of the Moon, Santana Abraxas, and Janis' Rachmaninov.

First we will show the listening room and the Cogent True-to-Life horn loudspeakers, then close-ups of the various parts that go into making the loudspeaker, some artistic close-ups of the loudspeaker, some pictures of the Cogent field coil compression drivers and their constituent parts, the demonstration system's source components, some historical horn speaker components, and finally our listening impressions.

Other resources:

Our review of the sound in the Cogent True-to-Life / Welborne room at CES 2006

A Quicktime movie of a lecture given by Steve Schell at the OswaldsMill Tube&Speaker Tasting 2004

The drivers installed in the loudspeakers in this system are developmental prototypes, subject to constant revision, and are not fitted with refinements such as their production voice and field connectors. They feel that they look rather crude at present, and they keep intending to upgrade the loudspeakers to the latest versions.

 

 

 

The TV in the center will affect sound-staging somewhat - as we know from having similar setups over the years ourselves - mostly to do with the solidity of images slightly off axis and sound-stage depth..

 

 

 

The room is heavily dampened, which seems to improve the ability of the large loudspeakers, horn loudspeakers at that, to work in a room this small.

 

 

 

 

Now we will just show a number of pictures of the loudspeakers.

 

 

 

 

 

The prototype loudspeaker enclosure itself, one of many Cogent has used over the years, is only a means to and end, and not the end-product itself. It is a means by which they can demonstrate the capabilities of their modern compression driver technology.

 

 

 

 

 

The size of the speaker, and its appearance, as not as imposing as a number of other loudspeakers on the market.

 

 

 

 

 

The loudspeaker enclosure, and its compression drivers, are a work-in-progress as the try to extend the frequencies covered both up towards 20K Hertz and down as low as possible.

 

 

 

 

 

The insulation on top of the upper horn does not seem to be for sonic purposes, but rather as a place to cache tools close by without damaging the loudspeaker enclosure - and probably to keep the tools from sliding off and falling on delicate toes.

 

 

 

 

This photo displays both the low-frequency driver, on top facing down into the lower horn, and the high-frequency driver, on the back of the top horn.

 

 

 

 

 

Here we see a close-up of the low-frequency driver. The driver requires both a signal, just like ordinary cone drivers, and an additional power source to energize the electromagnet, unlike ordinary cone drivers that use a large magnet.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Here we see another view that shows both the low-frequency driver, on top facing down into the lower horn, and the high-frequency driver, on the back of the top horn.

 

 

 

 

 

Here we see a close-up of the high-frequency driver. Like the bass driver, this driver also requires both a signal, just like ordinary cone drivers, and an additional power source to energize the electromagnet, unlike ordinary cone drivers that use a large magnet.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Here we see the mouth of the subwoofer horn in which lies the subwoofer's amplifier.

 

 

 

 

 

 

 

 

 

 

 

The subwoofer's amplifier.

 

 

 

 

The Cogent horn loudspeakers in several shots that show off the art of the speaker designer.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

The high-frequency Cogent compression field coil driver at the mouth of the upper horn.

 

 

 

 

 

The throat of the upper horn.

 

 

 

 

 

Upper and lower horns.

 

 

 

 

Earlier this year at the factory where the parts of the field-coil compression driver are manufactured on state-of-the-art Cogent-owned (to keep the driver's price down) machinery [photo supplied by Cogent].

 

 

 

 

 

This section looks at the three primary parts that go into constructing the Cogent True-to-life compression field coil drivers.

This phasing plug is from their Cogent DS-1428 midrange / high frequency driver. The radial slits are cut to great accuracy with a wire EDM machine, a difficult and expensive process. Cogent has applied for a U.S. Patent on the phasing plug design.

 

 

 

 

 

Precision machining not available to compression driver designers in the early parts of the 20th century.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Here we see photos of the 'coil' itself.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Heavy! Maybe 40 lbs.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

No, Neli doesn't drop it...! But I thinks she wishes I would stop taking pictures already.

 

 

 

 

 

This highly-specialized membrane is the diaphragm of the Cogent DS-1428 and is what is controlled and vibrated by the field coil in order to produce the sound.

 

 

 

 

 

As you can see it is very small and light-weight.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Now a few pictures of the modest system we used for the demo. We heard both CDs and LPs played on this system during our short stay.

 

 

 

 

 

Denon CD / SACD player, DEQX digital room correction processor, and a vacuum tube preamplifier.

 

 

 

 

 

The turntable.

 

 

 

 

 

The turntable obviously has a highly modified arm - a work in progress we understand.

 

 

 

 

 

A close-up of the experimental tone arm. We got the impression that they were just tweaking with the tone arm for fun, trying out some ideas.

 

 

 

 

 

The 300B-based monoblock tube amplifiers.

 

 

 

 

 

The 300B-based monoblock tube amplifiers.

 

 

 

 

The 300B-based monoblock tube amplifiers.

 

 

 

 

Not sure what this is.

 

 

 

 

This is one of the original horns used for the Cogent True-to-life loudspeaker, as the team experiments with what sounds best.

 

 

 

 

 

Everybody has to have their wall of LPs (Except us. We have a utility closet of LPs).

 

 

 

 

 

Old horn designs from yesteryear. I think one of the original motivating factors for the Cogent design was that P.A. systems should sound a lot better than they do now. The home of one of the Cogent founders is across the street from a small public ball field that has a P.A. system whose announcements were heard between demos, announcing the graduation of a number of L.A.'s finest students.

 

 

 

 

 

Here is a photo of an antique Lansing loudspeaker. Altec Lansing was one of the original designers of horn loudspeakers. Steven Schell is one of the two people behind the popular Altec Lansing historical information website.

This Lansing small two way speaker is the famous Lansing Iconic, generally regarded as the first two way studio monitor. The Iconic was introduced in 1937; the one in the photograph was built about 1940- 1942.

There is a profile of the Lansing Iconic on the Lansing Heritage web site at:

http://www.audioheritage.org/html/profiles/lmco/iconic.htm

 

 

 

 

 

More pieces and parts. Notice that other antique Lansing horn loudspeaker back there hiding in the corner? This home / workshop is just chock full of the *coolest* artifacts.

This photo shows various horns and drivers made by Lansing Manufacturing Company and the early Altec Lansing Corporation. The gray cone drivers stacked on the enclosures are mostly very early JBL products, built in the pre 1950 Jim Lansing era.

 

 

 

 

Contrasting this with the Cogent True-to-Life room at  CES 2006, this system had a serious disadvantage with respect to the source components and amplification. The room here also seemed slightly narrower than that at CES - although  both rooms were quite small rooms, considering the rather large and verrrry efficient loudspeakers.

Our primary goal during the listening session was to answer a number of questions we have had since hearing these speakers at CES; primarily "Were we crazy?" Were we just imagining the high-quality of the sound - the purity, the dynamics and ease with which it handled mini-, micro- and macro dynamics, and a number of other key properties of music that it seems that other loudspeaker technologies must struggle to get right?

Well, no. We weren't crazy. Whew! Get to avoid the therapist's couch for a few more weeks anyway.

The Cogent development team has been working on getting their high frequency driver to handle high enough frequencies in order to satisfy the requirement that no additional tweeter should be required in order for the loudspeaker to reach the standard 20K Hz high frequency mark. They seem to be getting very close, even though in this system, it wasn't all that evident except in perhaps a little more solidity of the imaging and perhaps more evenness in the frequency response, especially in the midrange and upper-midrange. Not talking here about flatness so much as good even-handedness across the frequency band in terms of dynamics and character - something only the best speakers do a great job at. Even with large horn mouths in quite a nearfield setting -- the listening chairs maybe six feet from the horn mouths -- the drivers seemed well integrated.

As far as further details about our listening impressions, well, there is only so much we can deduce from listening while trying to subtract the problematic effects of  the associated components. 

It is interesting that the system sounded as good as it did - certainly better than all but one or two systems at HE 2006 a few miles away - being as it was kind of heavily weighted in terms of quality on the speaker side. We know of other systems that are heavily weighted on the source side - one example is the Continuum room at HE 2006 this year. It seems like it is much more common in Europe to spend most of the system budget on the loudspeakers. Whatever works, I guess [by which I mean we are not going to get into the debate about which of the two approaches is 'better' - not in this report, anyway].

 

 

 

 

 

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