In Reply to: Altec Model 19 - N1201-8A Crossover Question posted by Synthsayer on August 29, 2015 at 13:41:44:
The T-Filter with 2 ohm resistor at R2 transformed my okay sounding 2 way system that uses EV DH1012A driver with FaitalPro LHT142 into one of the best sounding speaker systems I have ever heard.
Even running off a measly 100W Denon AVR, the sound jumps out of these things the way it should with a high efficiency system. In addition to that, they seem to blend well with the other speakers in the surround system.
My center channel speaker is built using an old Sears Roebuck mahogany record cabinet my father bought in Memphis in 1949. I sealed off the top section of the record storage and put an MCM 10 inch 'pro' :-) woofer in it, then set a horn cabinet on top of it. My AVR, cable box and Roku are in the bottom.
If anyone is experimenting with passive crossovers and filters for systems that use horn loaded high freq drivers, they should strongly consider trying the Altec 30904 style T-Filter seen in the above diagram.
I wish I had a way to do some testing to see exactly what the response is but I don't. All I can say is that I can hear cymbals and hi hats, synth noise effects, and reverb effects in music much, much better; way better than I ever expected. I listen to a lot of old Bob Marley and reggae dub like Scientist that has lots percussion and synths.
Here's a link to a nice album by Scientist:https://youtu.be/B8LjzHKMLh4
I do have the new Dayton measurement mic for iPhone, so I may try some measurements if I can figure out how it is done.
Since this system only uses a 1st order LP filter, another dramatic improvement came from using a Parallel Notch Filter for cone break up areas to give the impression of a steeper crossover and as Baffle Step Attenuation. After using 4th Order LP filters, I really like the sound of the system this way much, much better.
Good luck and thanks to all who contributed to this effort. Your help was invaluable.
TLP
"Ad Astra Per Alia Porci", - To the stars on the wings of a pig: John Steinbeck
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Follow Ups
- RE: Altec Model 19 - N1201-8A Crossover Question - Synthsayer 09:33:45 09/03/15 (0)