Well, Klipsch put the T-35 into his corner horn, so the problem was minimized. John Meyer and I knew that the midrange horn was directional too, so designed to ease the pattern disparity at the transition frequency (4KHz) with the T-350. The GD Wall of sound made an arc of T-350's to cover a broader dispersion. Please Google: 'Grateful Dead Wall of Sound' for photos of what was done.
As with all horns, there are 'tradeoffs. For us, good frequency response, on axis, was most important. All speakers suffer pattern problems, many even worse than the EV series tweeters.
As with all horns, there are 'tradeoffs. For us, good frequency response, on axis, was most important. All speakers suffer pattern problems, many even worse than the EV series tweeters.
John,
If you want to talk about EV tweeters here is the cats meow: http://archives.telex.com/archives/EV/Drivers/EDS/T-3500 Ionovac EDS.pdf
If you want to refer me to the wall of sound look back a few posts to where I explained why the SPL was not delivered to a single person.
There really have been improvements in horn coverages. Don Keele wrote a nice how to paper and AX had a recent series on just about every horn design and the tradeoffs.
The wall of sound was ahead of it's time, but as digital computers have become common the ability to measure has improved and as a result products are much better. 30 years ago I don't think anyone used a laser interferometer to look at case, horn or cone motion, today it is standard practice.
Look let us get real, IC's have surpassed discrete devices for audio circuits, digital audio is perfekt and there is no need for any improvement. All audio designs are just going downhill from the days of old. Just ask anyone with an IPod listening to MP3's!
I made a somewhat similar journey …
It is a journey on which many died en route and from which many more never fully returned. There are none I ever missed.
Ed, it DID get pretty loud, onstage, on occasion. We had a B&K sound level meter and we got 130dB on occasion. I will have to ask my friend, Dan Healey, the mixing engineer, for further input. Also, I have a message to Don Keele. He should be able to answer the questions about the new-old T350-T35 tweeters. I DO know what we (John Meyer and I) measured in Switzerland.
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Hopefully, we have fully discussed the 'errors' of the past, and can move forward into a 'brave new world' of audio perfection, cost effectiveness, and common sense.
Back in the 1960's, I looked forward to making a full phono and line preamp with a single 4 channel IC. Who could want anything more? Of course, slew-rate and high noise limited our efforts then, but what about today? It should be easy to build a pretty good preamp, with only one chip. After all, a Dyna PAS-3 tube preamp had no more gain blocks and it did pretty well.
Why was this approach not used, to make audio more cost effective?
Back in the 1960's, I looked forward to making a full phono and line preamp with a single 4 channel IC. Who could want anything more? Of course, slew-rate and high noise limited our efforts then, but what about today? It should be easy to build a pretty good preamp, with only one chip. After all, a Dyna PAS-3 tube preamp had no more gain blocks and it did pretty well.
Why was this approach not used, to make audio more cost effective?
130 "C" weight fast response is quite reasonable, also very loud, but in practice only 10% of "A" weight fast response. Still a bit more than is permitted under current OSHA standards. 125 bragging SPL would be allowed for 15 minutes even today.
Do I doubt you got good measurements from the T35's with the high pass capacitor and a B&K meter, no, just today we can measure much more.
So the moral of the story is data is nice, understanding what it means is better, and John even without LSD you are still .... doing Doo Wop!
Technically, it's a viable approach; however, the economics don't make sense. How many phono preamps are sold per month? The key word is "amortization."
I still make phono preamps, and will continue to do so. I am always getting asked for a cheap phono stage, just to play back someone's Empire turntable and Shure cartridge or its equivalent, so it might be a useful inclusion.
We should be able to use existing parts from major manufacturers and do the job. No need to customize. Of course, tubes are really 'over the top', psychologically obsolete, and unreliable. Discrete solid state is getting harder to find, and much more expensive. Time to move on to an quad IC and get it all done at once. I might allow a second IC for servos, just to improve the reliability of the unit, in order to remove any need for coupling caps.
We should be able to use existing parts from major manufacturers and do the job. No need to customize. Of course, tubes are really 'over the top', psychologically obsolete, and unreliable. Discrete solid state is getting harder to find, and much more expensive. Time to move on to an quad IC and get it all done at once. I might allow a second IC for servos, just to improve the reliability of the unit, in order to remove any need for coupling caps.
I certainly wouldn't use quads - and I like op amps
single/duals, in composite topologies with 2 op amps/buffers in a loop, together costing <$5 can achieve much higher performance on some critical specs than >$20 single chips
choose each of the input, output devices for the specs that match their circuit roles
single/duals, in composite topologies with 2 op amps/buffers in a loop, together costing <$5 can achieve much higher performance on some critical specs than >$20 single chips
choose each of the input, output devices for the specs that match their circuit roles
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Here is the classical Self Precission MM preamp i modified with recent dual Fet Opamps to safe some elcaps.
I also did the subsonic filtering a bit less agressive. The result i got is very good.
Discrete circuits can beat it subjectively but it may be hard to better the measurements.
I call that common sense and cost effective.
I also did the subsonic filtering a bit less agressive. The result i got is very good.
Discrete circuits can beat it subjectively but it may be hard to better the measurements.
I call that common sense and cost effective.
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