Topic: 2000 Tweeters!!!

[James]

After a good day of listening to the new and improved tri-amplified line source array, I'd have to say that this speaker system finally sounds like it is complete!

There is no doubt that the extreme high end it now there and completely in your control!

I can pick out individual instrument sounds now like never before.

I want to integrate these new tweeter lines into the surface of the full-range lines, finish them up and try to sell them as a system.

Know anybody who wants to buy a kick-ass pair of speakers? 

James. 

[drlava]

would you build another set for yourself?

[James]

Yes, of course! ~ With the money I get from these! 

I have a really cool idea I want to make.

I want to make a very modular stack, such that no one pices is too big or heavy.

But, they would all stack together to become one totally awesome speaker system.

I want to put the power amps in the boxes with the speakers.

And I want to use this digital, 3-way crossover from Behringer:

http://www.parts-express.com/pe/showdetl.cfm?Partnumber=248-669

James. 

PS. You should come over and hear them!

There are 160 driven voice coils in this system! 

(72) tweeters
(72) 3.5" x 2" TV full-range speakers
(16) 8" woofers

EDIT:
There are 186 driven voice coils in this system! 

(98) tweeters
(72) 3.5" x 2" TV full-range speakers
(16) 8" woofers

[Fanny Pack]

Yes, of course! ~ With the money I get from these! 

I have a really cool idea I want to make.

I want to make a very modular stack, such that no one pices is too big or heavy.

But, they would all stack together to become one totally awesome speaker system.

I want to put the power amps in the boxes with the speakers.

And I want to use this digital, 3-way crossover from Behringer:

http://www.parts-express.com/pe/showdetl.cfm?Partnumber=248-669

James. 

PS. You should come over and hear them!

There are 160 driven voice coils in this system! 

(72) tweeters
(72) 3.5" x 2" TV full-range speakers
(16) 8" woofers

Interesting ideas.  It would be cool if you could buy a giant speaker in seperate moveable pieces that seal together to create one large enclosure instead of several boxes.  That would allow more volume for the bass speaker and would make the individual pieces lighter.

In regards to putting power amps in the enclosures.  What about cooling?  And would that make the long low level lines running to the amps from the preamp successible to noise?  Or do you handle that with differential inputs like on scanners?

[drlava]

Also, don't 'audiophiles'  try to isolate their amps from the vibrations from speakers to minimize microphonic pickup in the amp circuitry?

[James]

These are good questions.

First off, the woofer boxes will be perfectly tuned for the woofers that are in them.

I use a technique called isobaric coupling. This puts two identical woofers together either face to face or back to back with a small sealed chamber of air between them. The coils are wired out-of-phase so the cones move to complement each other. This becomes one woofer that now has twice the moving mass, twice the spring coefficient, twice the thermal power rating, half of the impedance, half of the required box volume, the same cone area, AND since it is now a symmetrical moving element, even-order-harmonic distortion is eliminated! As long as each woofer gets its own box of the required volume, you don't need one big box.

In each of the woofer boxes that are behind the line source arrays, there are four identical 8 inch woofers. You can only see two. There is only one volume of air behind them that is about 7 cu. ft. It is tuned to resonate at about 20.5Hz and the system is about -3dB at 18Hz.

In the next design, I'll just put two woofers (one out, one in) into a box of about 3.5 cu. ft. and power it with an amp made for 4 ohms.

Before I got into lasers, LaserBoy and using a sound card to make laser signals, I wrote an application that uses a sound card to measure frequency vs. voltage. With this I can measure frequency vs. impedance and frequency vs. phase angle. With this tool, I can measure everything I need to know about a speaker in order to put it into the perfect box and tune the port.

As far as vibrations and all that... I'm not worried about that. I want to use amp kits from here:

http://41Hz.com

These kits are based on Tripath chips. They are a totally new concept in audio amplification. They are switch mode audio power amps! They are the most efficient amps around. Almost all of the heat will be in the voice coils.

I'm not sure what kind of signal cables I'll be using, but all of the Behringer active crossovers have XLR outputs.

James. 

[James]

I would say it's a safe bet to say that if you heard these speakers, you would agree that they are the best sounding speakers you ever heard, anywhere! 

You aren't going to find too many speaker systems out there that can respond well below 20Hz that have such low distortion and compression. Plus the stereo image is amazing!

I can hear a guy tapping his foot in a Montgomery Brothers jazz recording! 

James. 

[Lazerjock]

James, the next time I'm in the market for home speakers, I'm contracting you to build them.
I'm was very impressed when I got to see the other speakers you built. They are works of art.

[Fanny Pack]

Pretty cool speakers.  I made a pair when I was in about the 12th grade.  Nothing like what you have but I had to look into the volume tuning so I kind of know what you are talking about.

[James]

Check this out.

They adjusted their tweeter deal!

200 Onkyo Tweeters for $10 (Limit 2 cases per Customer)

James. 

[James]

I just got a Behringer 3-way stereo crossover today!

http://www.parts-express.com/pe/showdetl.cfm?Partnumber=248-668

Since my order was again over $100, I also ordered two more boxes of tweeters!

So I have 2,400 tweeters now!

I am refinishing the big line source arrays and fitting the tweeter lines into the fronts of them.

I decided to go with 49 tweeters in each; 7 x 7. That will make the tweeter lines almost the full height of the cabinet.

I have been taking pictures of the process and when it's all done I will post everything.

James. 

[drlava]

Nice, I hope I can hear them before they are sold.  By the way 8 series groups of 6 in parallel (48) would give you 8 ohms at AC, all evenly driven.

[James]

I really like the 41Hz.com chip amp kit AMP3 or AMP6. These things can drive from 4 to 8 ohms. From what I've heard, they are the flattest at about 6 ohms!

I can tell you that a line of 36 (6 x 6 = 6 ohms) sounded fantastic!

James. 

[James]

Check it out!

I have pictures of the recent speaker surgery.

[James]

more...

I got some sheets of black velvet stick paper today. I'm going to cut it tor fit nicely around the tweeters to cover up the gaps between them and the cabinets.

BTW They sound like they are totally worth the $4.90 I paid for them! 

Well.... now, maybe I can get back to working on LaserBoy for a while! 

James.