Front horn loaded bass reflex

[mikebake]

Me too! I've got 4560's; would like to see your results. Thanks.

If anyone is interested I have JBL 4560 data aplently with either TAD 1601a or various 16 inch Altec drivers. Have MLSSA scans or in room RTA data.


Cyclotronguy

[Cyclotronguy]

OK guys;

This is the only in room scan that I have, taken with a ACO Pacific mic and preamp from the listening seat 13 feet from the speaker.

Room 15 feet X 25 feet X 8 feet

Drivers
Altec 416-16Z
TAD 2001

Bass Cabinet
JBL 4560 tuned to 40 Hz

Compression Horn
Altec 511B

[Steve Jones]

My first post here after lurking for months.

I was looking at ways to augment the top end of my Altec model 19s and ran across the EV Tweeter thread about substituting a BMS compression driver for the stock 902-8. It seemed an easy bolt-in and Zilch had even done the sims. In an email to Zilch he told me to give it a try, and to post the results here.

But they might not work, as I had purchased the 19s with the "upgraded" Iconic Model 19 crossover. Looking the circuit over, it does not use stock valued parts with high grade components, but is a new design with above average components (homewound 12 GA inductors, Dayton caps, etc).

I remembered some TAD 2001s I was using about 10 years ago in a system using Lowther PM5As with 150Hz Chapman horns on top of Karlson Kouplers (each with an Eminence 15 inch woofer). The TADs were used with EV T-35 horns wth the phase plug ground out. The TADs left a lastingly good impression on me as I was forced to get rid of my horns and downsize my lifestyle.

So now I'm living large again, and in the process of pondering whether to get the BMS drivers, a pair of early pre-1990 TADS came my way.

I read up on these pages on Cyclotronguy's experiences and wrote him. He generously send me the info he had on how his TADs on 511 measured.

So, I simply bolted them in (sans bugscreens) and am amazed at the sounds my 19s are now making. The TAD 2001s seamlessly fell into place with the 416-8C, and opened up the top octave. In comparison, the 902s were MIA in the top octave (to my modern ears), and exhibited a bit of image "push" and "splash" (diaphrams going chaotic?). Are the TADs better? You may prefer the character of the 902s. But I sure like the 2001s.

Next project: Berhinger DCX24/96 and biamping them.

Thanks for the great website and all the great people here.

-Steve

[RKLee]

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In comparison, the 902s were MIA in the top octave (to my modern ears), and exhibited a bit of image "push" and "splash" (diaphrams going chaotic?). Are the TADs better? You may prefer the character of the 902s. But I sure like the 2001s.

Next project: Berhinger DCX24/96 and biamping them.

Thanks for the great website and all the great people here.

-Steve

Welcome. I too am a newbie at this new tech sound stuff, at least in terms of the computerize RTAs etc.

I have a home-built cabinet with 2 Altec 12" 414, 806/811 driver/horn. I built it in late 1975, I too felt that there was not enough high end even with the aluminum diaphragm. For me I installed an EV T350 super tweeter, and tri-amped it using a DeCoursey(local to Los Angeles, now gone) crossover, with Crown D75 amps for the lows and mids, and a SWTP(Southwest Tech. Prod.) 25 watt kit-built amp.

[Zilch]

Though I've never worked with them, I have heard them, and the TADS are a worthy upgrade. From the advertising, I would expect the Iconic XO to be a replicate of the standard M19, with upgraded components. Until someone publishes the schematic for comparison, we're not going to know the differences, if any. The BMS drivers are relatively inexpensive, and you might want to give them a try as well and post your findings.

It's clear many Altec owners have found it desirable to augment high-frequency response via one means or another. For others, the stock configurations provide perfectly satisfying performance. Certainly Altec enthusiasts now have access to more information than was generally available prior to it being posted here, and new options to consider and pursue as desired. For whatever it might be worth, I am pleased to have been a participant in that.

[Cyclotronguy]

And the wife still refuses to let me take the modified 4560's out of her office / studio. But,with the very kind assistance of "Widget" something better may be on the horizion.

Cyclotronguy

[Steve Jones]

Until someone publishes the schematic for comparison, we're not going to know the differences, if any.

I wouldn't feel comfortable tracing out the schematic and publicly posting it. It's Iconic's intellectual property. I'll leave it to them to publish it.

For whatever it might be worth, I am pleased to have been a participant in that.

-Steve