TLG Factory Tour
Article By Steven R. Rochlin
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  Amazing things happen when creative artisans use new technology to solve age old problems. Sometimes we must use the newest technology to prove that the proper solution lies with older technology! This brings us to horn speaker manufacturer TLG. The Enjoy the Music.com WCES '99 show report gave the world their first glimpse into this new engineering marvel. In fact TLG won the Design and Engineering Showcase Honors at the '99 CES. Not one to leave any stone unturned, i decided to take a much closer look, and listen, into this new concept that was also featured by The Robb Report (May 1999) by none other than all around reviewer extraordinaire Ken Kessler. This tour took part during the Chicago Audio Society meeting.

This new concept was in not bending and shaping wood to make a horn speaker enclosure. Nor was it by using large blocks of wood and then carefully shaping them. What TLG does is by using computer 3D CAD designing, they cut many thin pieces of wood which are glued together. In actually this was not totally a "new" concept per se. Years ago i was starting a report about the Platinum Audio Air Pulse 3.1 speakers which were built using this same concept. It seems the genius of TLG combined with the brilliance of speaker designer Phil Jones produced an amazing speaker as first seen by the world on the Enjoy the Music.com WCES '97 show report.

Because of this new and unique design, i decoded to tour the then Platinum Audio facility (editors note: Platinum Audio has since went out of business and the Air Pulse 3.1 speakers are technically no longer produced to these standards). As seen below is the basic building process of the old Platinum Audio speakers which mirrors the construction technique of the TLG designs. It must be said that TLG was a good part of the genius behind the Air Pulse 3.1 and as such, their designs may eclipse by a good margin those of Platinum Audio.

Seen here are the many different pieces which make up one of the midrange horns of the old 3.1 design. As you can see, many precisely cut pieces are made to exacting standards to help form the final product. Since using curved wood can be problematic due to the wood "relaxing" (naturally, wood expands and contracts due to heat and humidity), Platinum wanted a better system. With the TLG system, their assembly design is capable of consistent tolerances of eight thousandths of an inch! These pieces are aligned and glued to form the solid piece as seen in the photos below.

A special glue is used to attach all the pieces together which does not expand nor contract over time and temperature. After the glue, the entire assembly is inserted into a special thick plastic bag where a high pressure vacuum is used to insure that the entire assembly has even and thorough pressure to insure proper even cementing of the pieces together. Notice the "stepped" look after cementing.

Seen to the right is the final unstained product. There is a small and vital step i have left out. That step is the actual shaping of the piece once the glue has fully dried. During one of my visits i had the opportunity to see this in action. Basically a vary large lathe is used and the piece is hand shaped. While this is a long precise process, it helps to firm the very smooth shape as seen above. TLG chooses to leave their shapes in the more raw "stepped" form as all this hand crafting is generally not necessary yet adds a huge price penalty to the final product. As an added bonus, i have chosen to publish the full CAD images of the 3.1 design below.

Getting back to the genius behind the 3.1 and TLG designs... i must also say that TLG has further advanced speaker design to an incredible degree! The TLG speakers are made using a laser cutting system capable of making precise cuts to very small fractions of an inch (seen right)! The design is first done with computer 3D CAD followed by prototyping. TLG's "meat and potato" bizz is with cutting gaskets for the speaker industry. They are no strangers in cutting wood! TLG was contacted by Platinum Audio for assistance with their then new model Air Pulse 3.1 speakers and the rest, as they say, is history. Seen below is a computer 3D CAD drawing of their current design as seen at CES '99. To make it all seem simple, you make a 3D CAD design, enter it into a computer, and the computer driven laser cutter does the rest. Of course this is a vastly oversimplified overview of the entire process.

3D CAD Drawing

Actual speaker seen at the CES '99.

As you can see above, here is a raw, unstained TLG midrange/tweeter module. Notice the "stepped" look. The great thing about computer design with laser cutting is that the internal cavity structure and inner supporting beams are so precise that there is absolutely zero guesswork as to the cubic feet of airspace the speaker is using. In other words, the enclosure each speaker uses can be not only precisely shaped, but also precisely sized and properly cross braced as well! This is where new technology meets old school horn speaker design.

So why horn speakers? Because TLG feels it is the best design of all to reproduce the subtle nuances of live music. Not just in large dynamics as horns are know to excel in, but also in microdynamics as well. To the right is the crucial bass horn. Anyone who knows horns realizes that reproducing the lowermost frequencies can be problematic. TLG solves this by using a 3 to 1 folded-horn design. The bass driver uses a three dimensionally folded horn. This is a first! So why is it important? Because every dimension can be designed in to, and in turn, dictate the "finest in sound transmission" according to the TLG representative. Unlike, say, the Edgarhorn, there are curves both inside and out within the lower frequency driver enclosure. If you look back at the Air Pulse 3.1 bass driver black and white 3D drawing seen above, you can see how the woofer loads a spiraling cavity. This cavity helps to amplify the output and also give the bass driver physical length to produce the lowermost frequencies. As we all know, the lower the frequency, the physically longer the sound wave is and hence, the longer the enclosure needs to be.

My visit to the TLG facility corresponded with the wonderful Chicago Audio Society meeting. During this meeting we all had the opportunity to hear many different genres of music in their extremely large facility. The system used was as follows:

Cary CAD-300SE monoblocks
Cary SLP 98 preamp
Cary CD-301 CD player
Straightwire cabling throughout

We listened to a CDR of Mark Speilburg "Marco's Drum Improves" from Speilburg Audio Labs in St. Louis (314) 725-3220 . It sounded amazingly dynamic! Only a small hint of the uppermost highs seem to be lacking. Of course this could be due to any number of things. These speakers were easily, and realistically, filling up quite a large space with sound using only a few small watts! Everything from small jazz to Metallica was played and the Members of the Chicago Audio Society seemed very pleased. There was a definite rightness in the dynamics which can easily be lost on less sensitive designs regardless of how many watts of amplification are used. Maybe it is that some speakers designers have gotten lazy and allow their designs to have impedance sweeps from 2 ohms (or less) to 32 ohms (or more)? Maybe it is time more speaker designers became more responsible for properly designing speakers with smoother frequency and impedance curves.

Another great benefit of computer designing is that time alignment is insured to utmost precision. The one thing i have not covered yet is the crossover which uses "premium grade polypropylene capacitors" and air core inductors. It is all enclosed in an enclosure which is optimized to reduce outside vibrational interference from affecting it.

Processional TAD drivers are used throughout. The horns themselves, such as the bass, use 1/4" mdf. The original design for the midrange was in radial horns, but the final design wound up being tractrix horn. The tactrix gave the speaker a more optimum matching sound with the rest of the design. TLG used only the best crossover parts and speakers.

TLG's main goal, they told me, is to offer their services to those who desire a speaker of the owner's specifications or a show piece. This is the great flexibility with computer aided design combined with a computerized laser cutting system. Of course custom color/finishing is included as well.

The total specifications of their Series I unit is as follows:

Frequency response 45Hz to 35kHz (-3b)
Impedance from 4-16 ohms (8 nominal)
Sensitivity 107 db/w/m
Harmonic distortion 1% @ 107db
Power rating is 35 wpc max which yields 122 db SPL @ 1 meter
Height x Width x Depth   70"x116.75"x32"
Weight  2,500 lbs. (approximate)

TLG Acoustic Design, Inc.
4900 West Bloomingdale Avenue
Chicago, IL 60639

Voice (773) 889-4976
Fax (773) 889-2815

http://www.tlgacoustic.com