Przem's Phase Linear 700 Series II White Oak Conversion

Joe, 6 months ago I saw one go on e-bay for 3400.00 I paid 875.00 for mine..that was a few years ago...
 
A lot of us were watching Don Kirchner's Rock Concert or the Midnight Special when you had your first diaper change...
 
orange said:
A lot of us were watching Don Kirchner's Rock Concert or the Midnight Special when you had your first diaper change...
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Thank god for YouTube because that's where I get my don kirchner and midnight special and old grey whistle .....
 
Skynyrd77 said:
Whats so funny????? Lmfao!!!
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.... at 37, I can't believe u haven't come across bi-amping and and active x-overs.
i didn't mean to offend, sorry. :(
i guess, not so much laughing, but surprised. it's been quite the trend for at least the last 4 or 6 years.
hasn't really caught on, coz of iPods and earbuds etc., and it only appeals to a limited few like the nutters here that really love their music, and the equipment that takes it to a higher level.
 
20,000 Watt Home Hi-Fi System (electronic x-over and 17 PL400’s with lots of horns)

More on the recent discussion: Audio magazine, April, 1976. pp. 44-56. By Richard S. Burwen

[...] Each of the five speaker horns is 13 ft. deep and has about 64 sq. ft. of mouth area. [i.e. 8 foot x 8 foot] The horns are conical, in preference to exponential, in order to produce a gradual low frequency rolloff, instead of a sharp cutoff. As it turned out, due to reinforcement from the room, the average low frequency response on one third octave bands is flat down to 16 Hz without equalization.

Each speaker horn contains 30 Cerwin-Vega tweeters, a midrange horn with two JBL 2440 drivers, and two Empire 16 in. woofers. In addition, the left-front and right-front horns have two 24 in. Cerwin-Vega woofers, mounted on the doors. These woofers are equipped with feedback windings to linearize their acoustic output over their range.

The rear speakers, which are shown diagrammatically in the room plan, point towards the rear of the room so as to provide reflected sound....the storerooms between the front speakers constitute a 200-cu. ft. back enclosure. The rear speakers vent into the room at the ceiling level in the manner of a bass-reflex speaker....

The entire room is solidly constructed of concrete, cinder clock and extra heavy plaster. Although the horn walls are made of 4-in. filled cinder block, I am amazed at how much these can vibrate. If I were to build a room like this again, I would use 8-in. thick walls.

The ceiling is wavy so as to diffuse the sound and the low points of the ceiling conceal heavy steel beams which support the house above.

Phase Linear-400 amps To drive these speakers there are a total of 17 Phase Linear 400 amplifiers [200 watts RMS/channel @ 8 ohms].... Each woofer, midrange horn, and set of 9 or 12 tweeters is driven from one 200 watt amplifier channel. With the electronic crossover at 50, 400 and 5,000 Hz ahead of the amplifier, the speakers can produce the same sound level that would be produced by a single 20,000 watt amplifier.... The crossover filters utilize UM201 modules to produce 6-, 12-, 18-, and 30-db/octave cutoffs for the various drivers. In addition, the crossover provides equalization to lat acoustic response.

In designing and adjusting the crossover network, I used one-third octave noise measurements based on a six microphone average of omni-directional microphones for low frequencies and an average of two cardiods located in from of the left-front and right-front horns for high frequencies. The microphones used for adjusting the crossover frequency response are the same ones used for making recordings here, so the entire system is flat. On one-third octave noise bands, it measured flat within 1 1/2 db from 15 HZ to 20 KHz. Nevertheless, I find that when reproducing much of the prerecorded program material availible I use from 3 to 30 db of low frequency boost.

When you have a high powered sound system like this, one of the difficult problems to solve is to keep from blowing out 169 speakers at once. That is the reason for having so many speakers in the first place. The tweeters are wired three in series so that each can receive only 1/3 of the amplifier output voltage. All the speakers can handle the clipping levels of their respective amplifiers without mechanical damage. Nevertheless, during sustained clipping the voice coils can get too hot. To prevent overheating, there is an elaborate speaker protection system in each of the rear horns and one for the three front horns. The protection system has a total of 34 channels, each of which measures the amplifier power output, computes the voice coil temperture and disconnects its speaker with a relay before the voice coil gets too hot. The same system eliminates turn-on and turn-off thumps. In over a year of operation there has been no damage to any of the speakers. [...]

And in addition, an interesting short article on ‘why to upgrade your system with electronic x-overs’… - http://scrounge.org/speak/dynamic.htm
 

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bobbysdad said:
.... at 37, I can't believe u haven't come across bi-amping and and active x-overs.
i didn't mean to offend, sorry. :(
i guess, not so much laughing, but surprised. it's been quite the trend for at least the last 4 or 6 years.
hasn't really caught on, coz of iPods and earbuds etc., and it only appeals to a limited few like the nutters here that really love their music, and the equipment that takes it to a higher level.
Click to expand...

Ive spent the last 20 years going to concerts. This home audio shit is still a new thing to me. I've had my technics sp-15 for years. But other than that it's been get me by best buy crap. So there's a lot I don't know about:thebirdman::D
 
bobbysdad said:
.... at 37, I can't believe u haven't come across bi-amping and and active x-overs.
i didn't mean to offend, sorry. :(
i guess, not so much laughing, but surprised. it's been quite the trend for at least the last 4 or 6 years.
hasn't really caught on, coz of iPods and earbuds etc., and it only appeals to a limited few like the nutters here that really love their music, and the equipment that takes it to a higher level.
Click to expand...

Hell BD, I am 50 and never messed with biamping. Never really heard about it until I joined AK. I suppose it quite cool but I have to question using multiple crazy power amps... why would I want to use a 500w amp to drive tweeters that are lucky to see 20w? Mids don't take to 500w amps well either, hell, most woofers can't take it either. It looks cool but using huge amps basically at idle to drive tweeters and mids is just not cost effective for most people. I also am not a fan of drilling extra holes in my speakers for extra terminal plugs. I can see using low power amps for driving tweeters and mids but a rack of monster amps is just too much money to run a couple hundred dollars worth of speakers. If you have the equipment and money to do it, I am all for it but in reality, it's not something most 2 channel dudes do (or can afford to do)

Maybe I will look into it someday when I don't have kids in the house bleeding the wallet dry LOL
 
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