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Fried double subwoofer identification

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Does anyone recognize this subwoofer? It has the general appearance of a Model H but no external crossover. No sign of satellite speakers either. I would like to give it a try. Any info especially regarding weather it should have external crossover or not would be great. Thanks for the help!

john
fried 2.jpg fried 1.jpg
 
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JimPA said:
Can you post a picture of the driver?
Are there one or two enclosures?
Click to expand...

I will know more next week when the seller is back in town. All I have right now is the photos from the listing. I am curious to check it out.

Ohighway said:
https://www.t-linespeakers.org/classics/coffin/index.html

https://www.t-linespeakers.org/classics/friedH/fried_H.html

Probably one of these. Might have round instead of the oval woofers.
Click to expand...

If it is the oval woofers, I wonder if they are the same drivers as in my Transtatic I speakers. I was surprised how good the bass was when I first listened to them.

I think you may be right with the model H. I hope the crossover is internal. If not, I will have to build one. Probably get by with a low pass filter to start out with to get a feel for the sound.

Do either of you have listening experience? I was planning to either use this with an open baffle project I am starting or in my HT setup.

Thanks for your input I think there is a lot of potential for a nice restoration here.
 
Well it's a passive unit so careful matching with a pair of satellite speakers is essential. I know purists interested in maintaining originality will cringe, but if it was me, I'd rewire the woofers for use with a plate amplifier. That would allow easier matching with a wider variety of satellite speakers. If the sub drivers are in good condition and the price is fair, I'd go for it.
 
The Fried model H transmission line subwoofer has two Kef 8" drivers n the enclosure.
The crossover uses a 14 gauge 15 mh air cored inductor.
You do not want to use an iron cored inductor in the crossover.
The model T have one Dalesford 10" driver per enclosure.
 
Not on everyone's shelf due to expense and, depending on the wire gauge for an air core inductor, a resistance of around 2.5 ohms which translates to a significant insertion loss. Best avoid if you can.
 
homebrew said:
Not on everyone's shelf due to expense and, depending on the wire gauge for an air core inductor, a resistance of around 2.5 ohms which translates to a significant insertion loss. Best avoid if you can.
Click to expand...


The resistance of the 15mh 14 gauge air cored inductor is 1.17 ohms. not 2.5 ohms.
solen-perfect-lay-air-core-inductors-s1415_0-15mh-14awg-inductor
Air cored inductors are more linear than iron core and do not saturate.
I guess you know more than Irving Fried did about designing crossovers.
 
Jim, you might try re-reading my comment about wire resistance DEPENDING ON WIRE GAUGE. Refer to specifications from Parts Express.

https://www.parts-express.com/15mH-...0Ij_qQ8QoxF6tAMt3BO_OJuP0W3HBjExoCZWYQAvD_BwE

And I never inferred I know more about crossover design than Irving Fried. But you can't argue that for a subwoofer installation, an active crossover and separate amp is much better than a passive crossover with large power-robbing inductors.
 
homebrew said:
Jim, you might try re-reading my comment about wire resistance DEPENDING ON WIRE GAUGE. Refer to specifications from Parts Express.

https://www.parts-express.com/15mH-...0Ij_qQ8QoxF6tAMt3BO_OJuP0W3HBjExoCZWYQAvD_BwE

And I never inferred I know more about crossover design than Irving Fried. But you can't argue that for a subwoofer installation, an active crossover and separate amp is much better than a passive crossover with large power-robbing inductors.
Click to expand...

If you ever heard the difference between an air cored compared to an iron cored inductor you would never go back to to iron cored.

When it comes to subwoofer crossovers I prefer a passive series over a passive parallel network or active.

Fried had demonstrated his transmission line satellite and subwoofer systems using passive parallel, series and active crossovers.
His quasi 2nd order series resonant crossover circuits performed superior to an active crossover that used a separate amp for the subwoofers.
Quasi-transientP.html
blog0402.htm
 
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Oh that's pure bullshit I never implies anything of the sort. The overall thrust of my reasoning was that an active crossover if ultimately the best solution. Nitpicking and red herrings regarding inductors aside.
 
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homebrew said:
Jim, you might try re-reading my comment about wire resistance DEPENDING ON WIRE GAUGE. Refer to specifications from Parts Express.

https://www.parts-express.com/15mH-...0Ij_qQ8QoxF6tAMt3BO_OJuP0W3HBjExoCZWYQAvD_BwE

And I never inferred I know more about crossover design than Irving Fried. But you can't argue that for a subwoofer installation, an active crossover and separate amp is much better than a passive crossover with large power-robbing inductors.
Click to expand...

Do you understand why Fried used a 14 gauge air core inductor instead of a lesser gauge in this crossover?

The 18 gauge inductor you linked has a dcr of 2.4 ohms.
Fried's crossover schematic shows a dcr of 1.3 ohms for the 15 mh 14 gauge air core inductor.

ERSE 15mH 18 AWG Perfect Layer Inductor Crossover Coil


18 gauge perfect layer air core inductors are excellent for high quality crossover construction. The layers are wound very tightly and bonded together to keep the DCR to a minimum. The air core ensures no saturation, hysteresis, or other magnetic distortions. Made in the USA.

Specifications: • Inductance 15.0 mH • Wire gauge: 18 AWG • Core type: Air • DC resistance: 2.40 Ohms • Tolerance ±2% • Power handling: 300 watts RMS • Dimensions: 3-1/2" D.
 
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So ultimately, this transaction did not come to fruition. Lack of response from the seller and a last minute price change after we had agreed killed the purchase. At the end of the day I am pleased. I went looking at that major online vendor in the warehouse section and got an REL sub in used acceptable condition for half price. It showed up today in a box that had the old shipping labels removed. The inner box was factory sealed and the sub was perfect. It is an HT/1003and it is on first listen very tight and clean.

I guess it all works out....
 
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