Fried Transmission Line Satellite and Subwoofer Design.

daveapex said:

New Member too, I also want to thank JimPA and every one else who made this thread possible. I have a vintage pair of B2's from working at a HiFi store in the 70's and am now working on model C clones. Funny thing though I have realized through the years, it was not for the love of music that made these great speakers. It was finding music that brings out the passion of these speakers and the rest of the audio system. Got to honor those that designed and made such great audio equipment back in the day; like Bud Fried - Thanks

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What drivers will you be using for the clones?

I am considering the =
Wavecor TW030WA06 30 mm Textile Dome Tweeter with Rear Chamber with Ferrofluid 4 Ohm
$65.25 - Frequency Response - 1,500 to 25,000 Hz - Sensitivity - 91 dB 2.83V/1m
Wavecor WF152BD03 6" Balanced Drive Paper Cone Mid-Woofer 4 Ohm
$98.25 - Frequency Response - 70 to 3,500 Hz - Sensitivity - 91 dB 2.83V/1m
Wavecor drivers are being used in some of the upper PSB models and the listening area is the back of a step van; Hence the 4 ohms is a good match for the amplification. Their graphs show fairly slight slopes and should work well with a low slope crossover. I am not looking to match the same sound characteristics as a model C's. Just trying to incorporate Fried's concepts of the pyramid transmission line cabinet and slow slope crossover design. Thanks

JimPA said:

The C3L use the Hiquphon OW2-92-FS hiquphon.htm.
The only suitable drop in replacement woofer is the Vifa P17WJ00 scanspeak-classic-p17wj00-6.5-woofer for the existing crossover.
I have never tried this woofer but it's response curve is similar to the 6.5" drivers used by Fried.

One of the former owner's of Fried Products was selling the Silver Flute 2-wool-cone as a C3L upgrade.
This woofer has 6 holes and the baffle would have to be drilled to accommodate the driver.
The hole routing might have to be enlarged for it to fit.
I have never heard the Silver Flute driver but others that have used it like it's performance.
It would require a new crossover.
The last two pages of the document show the crossover for the Silver Flute driver.
I am glad this forum accommodates large files being uploaded to threads.

I would enjoy seeing some photos of the Fried drivers and enclosures you have.

The O4 enclosure IMHO is the best 10" transmission line enclosure designed by Fried.
Being deep it has less internal reflections compared to the O1 enclosure
It's .5 cubic feet larger than the O1 and T enclosures and is flat to 22-23hz.

I would get the butyl rubber surrounds replaced on the C3L drivers.
Fried did use foam rubber surrounds on the first C3L drivers then later switched to butyl rubber.

I know that the butyl rubber surrounds on my C6L Gefco drivers are thicker then most surround replacement kits.
One of Fried's former partners gave me a C6L driver that had a short in one voice coil so I dismantled the driver to see the voice coil.
This is when I noticed how thick the surround is.

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So it is best to replace the surrounds on the Carboneau drivers. The vented pole may present a challenge as typically the voice coil cap is removed to center the voice coil but I'll give it a try. I've succesfully replaced the surrounds on Phase Tech speakers whose solid cone presents a similar problem. Anyone have experience replacing the Carboneau surrounds? Good to know there is a suitable drop in replacement if I screw them up. Currently I'm using a Rogers LSB1 subwoofer with the C3Ls. I modified the sub's crossover as it was designed for their LS3/5A and was made to match its low efficiency and filter out the bass bump. I also have a pair of Rogers JR149 speakers I rotate in. The Rogers and Frieds have a similar tone quality IMO so they integrate well with the SLB1. The SLB1 is a relatively small dual sealed enclosure using a Kef B200 driver in each side. I'll post some pictures tonight.

jcwhite57 said:

So it is best to replace the surrounds on the Carboneau drivers. The vented pole may present a challenge as typically the voice coil cap is removed to center the voice coil but I'll give it a try. I've succesfully replaced the surrounds on Phase Tech speakers whose solid cone presents a similar problem. Anyone have experience replacing the Carboneau surrounds? Good to know there is a suitable drop in replacement if I screw them up. Currently I'm using a Rogers LSB1 subwoofer with the C3Ls. I modified the sub's crossover as it was designed for their LS3/5A and was made to match its low efficiency and filter out the bass bump. I also have a pair of Rogers JR149 speakers I rotate in. The Rogers and Frieds have a similar tone quality IMO so they integrate well with the SLB1. The SLB1 is a relatively small dual sealed enclosure using a Kef B200 driver in each side. I'll post some pictures tonight.

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When it comes to finding the exact replacement surrounds I would contact Bill Le Gall of Millersound / .
I know that not all butyl rubber surrounds have exactly the same thickness.
I say this from purchasing buyout drivers over the years.
The butyl rubber surrounds on my Fried Gefco drivers are thicker than any of the buyout drivers I have.

I’ll look Millersound up. The surround material appears to be rubber. Never understood the use of foam as it will turn to dust. My JR149’s Kef B110 drivers have the original rubber and are still plyable with no noticeable deterioration. I’ve attached a few pictures of the C3Ls. They’re being driven by a couple of Chinese made monoblock tube amplifiers that are clones of 1947 Williamson Amplifier and pre-amplifier minus the tone circuit. Note the SLB1 subwoofer under the equipment stand.

jcwhite57 said:

I’ll look Millersound up. The surround material appears to be rubber. Never understood the use of foam as it will turn to dust. My JR149’s Kef B110 drivers have the original rubber and are still plyable with no noticeable deterioration. I’ve attached a few pictures of the C3Ls. They’re being driven by a couple of Chinese made monoblock tube amplifiers that are clones of 1947 Williamson Amplifier and pre-amplifier minus the tone circuit. Note the SLB1 subwoofer under the equipment stand.

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IMHO the C3L enclosures are the best mid bass transmission line enclosures ever designed.
The lower frequencies that exit the transmission line terminus [vent] at the rear of the enclosure creates a large sound stage.

My C3L crossover matches the pre-1992 version. The literature shows after 1/92, the crossover was changed. No reason given and the drivers aren’t changed. The after 1/92 circuit removes the 2 ohm resistor in series with the tweeter and replace the 15 ohm resistor in parallel with the tweeter with a 30 ohm. Evidently Fried decided the tweeter output needed to be increased. Not sure what to think of that as the tweeter output sounds good to me and my HF hearing is not what it used to be. Maybe Bud was loosing his too.

jcwhite57 said:

My C3L crossover matches the pre-1992 version. The literature shows after 1/92, the crossover was changed. No reason given and the drivers aren’t changed. The after 1/92 circuit removes the 2 ohm resistor in series with the tweeter and replace the 15 ohm resistor in parallel with the tweeter with a 30 ohm. Evidently Fried decided the tweeter output needed to be increased. Not sure what to think of that as the tweeter output sounds good to me and my HF hearing is not what it used to be. Maybe Bud was loosing his too.

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IMHO Fried was trying to eliminate the use of a resistor in series with the tweeter by doubling the value of the parallel resistor.
The C6L crossover is identical to the pre -1992 C3L crossover except the inductor value is .33mh. since the Gefco driver is 5ohms.

JimPA said:

IMHO Fried was trying to eliminate the use of a resistor in series with the tweeter by doubling the value of the parallel resistor.
The C6L crossover is identical to the pre -1992 C3L crossover except the inductor value is .33mh. since the Gefco driver is 5ohms.

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What matters is does the change result in an overall improvement? This would be a subjective judgement so the only way to know if I like it is to perform the "upgrade". If I don't prefer it, I can change it back. I'm curious how the change effects the sound before I do it. Fried must have published some background to why they made the change. Interesting they went back to the earlier configuration with the C6L. Were the C progressions just driver changes or did the cabinet change?

jcwhite57 said:

What matters is does the change result in an overall improvement? This would be a subjective judgement so the only way to know if I like it is to perform the "upgrade". If I don't prefer it, I can change it back. I'm curious how the change effects the sound before I do it. Fried must have published some background to why they made the change. Interesting they went back to the earlier configuration with the C6L. Were the C progressions just driver changes or did the cabinet change?

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Decreasing the cap value of the Zobel on the C3L would flatten the woofer impedance higher in it's response.
I think Fried was trying to extend it's response a little.
The Zobel on the C6L uses 2 mfd and 10 ohm Re.
The crossover schematic is on post #28.
Fried changed crossover values claiming it upgraded the performance of the speaker.

The C3L enclosure is exactly the same with the C5L and C6L models.
Also the same is true with the enclosure of the O4-O6 models.

The C1-C3 use the aperiodic truncated pyramid until the transmission line C3L design was implemented.

The C1 used the Dalesford 6.5" bextrene cones with the Dynaudio D-28H tweeter.
There were two different Dalesford woofers used in the C1 model.
The D153/50 were in the early models.
I was able to purchase a pair of the D153/80 which were used in the C models sold for
professional monitoring applications.
These have a much larger motor structure to increase their power handling.

Dalesford went out of business so Fried had to change his source of drivers.
The C2 used the former Transparent Sound poly cones with foam surrounds with the Scan Speak 2008 tweeter.

The C3 used the Carboneau poly cones with the Scan Speak 2008 tweeter.
The first Carboneau drivers used the foam surrounds.
Later models have a butyl rubber surround.

The C3 came with the option of using the upgraded transmission line enclosure and was named the C3L.
There was never a C4L model even though the C3L was the fourth generation of the C models.
I remember the first C3L I listened to used the Scan Speak 2010 tweeter which was later changed to the Hiquphon OW2-92FS.

The short lived C5L model used the Focal 6K412L kevlar sandwich cone with the Hiquphons.
Fried included in one of his papers how Focal was not truthful with the response curves of their drivers.

Every Kevlar sandwich cone has a breakup above the rolloff which can't be attenuated with a low order crossover.
Others have discussed it on other forums.
post
post
post
I know that Fried was trying to get Scan Speak to make a 6.5" carbon fiber driver to replace the Focal drivers.
Since Scan Speak's tool and dies were set up for 7" and not 6.5" is probably why it never happened.
This is one of the reasons why he had Gefco source the drivers for his last generation of speakers.

Jim, thanks for the history lesson.

jcwhite57 said:

I’ll look Millersound up. The surround material appears to be rubber. Never understood the use of foam as it will turn to dust. My JR149’s Kef B110 drivers have the original rubber and are still plyable with no noticeable deterioration. I’ve attached a few pictures of the C3Ls. They’re being driven by a couple of Chinese made monoblock tube amplifiers that are clones of 1947 Williamson Amplifier and pre-amplifier minus the tone circuit. Note the SLB1 subwoofer under the equipment stand.

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Purchased these emblems from eBay seller burtnbec. Adds a nice finishing touch.

jcwhite57 said:

Purchased these emblems from eBay seller burtnbec. Adds a nice finishing touch.

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Back when Fried had Carboneau produce those drivers they were the first double stacked poly cones ever made.
Having the voice coil immersed in a longer magnetic field made the response more linear.
Some might think the second magnet was a shielded magnet but it's not.
The motor structure is similar to the C6L Gefco drivers on post #18.


Back in the early 1990's Meniscus and Zalytron sold the stock Carboneau versions that used only one magnet.
The stock versions performed well in the C3L and O4 transmission line enclosures but the oem Fried versions are superior.

Since then many have copied the use of the double stacked magnet structure in driver design.

Contacted Bil Legall and he gave me a reasonable price to replace the Carboneua surrounds. After removing them from the cabinets they were in worse condition than I thought Both woofers surrounds were punctured and were detached from the frame in places. Massive air leaks. On top of that one of the woofers was out of phase. Looking forward to re-installing them.

Salectric said:

This is one of my brother's speakers which I built around 1980. It has had some rough treatment over the years as you can see from the crushed corner of the satellite. The dome of the T27 tweeter is even crushed in. However, they sounded very good during my brief listen this past weekend. The bass in particular is tight and detailed yet rich and warm at the same time. As I said in an earlier post, I built these following the Fried plans for the H satellite and the O subwoofer but they were not from a kit. The O uses a KEF B139 which was not part of Fried's plans but was a woofer I really liked.

I had a schematic of the H crossover that a friend gave me based on his examination and measurements on his H kit. So the crossover values for the H satellite are the same as a genuine H but the particular components used were my own choices. The crossover between the satellite and woofer is as simple as can be. The H satellite runs full range on the bottom end but of course rolls off rather quickly in the bass, and the O subwoofer uses a first order crossover at around 110 Hz (a hand wound 12g air core choke). The choke started out as a massive choke for the H woofer which used a lower crossover frequency. When I used it with the H satellite on top, there was a dip in the crossover region so I unwound the choke bit by bit until I reached the point where I could no longer hear the dip. I then measured the choke and unwound the other channel's choke to match. Not very scientific perhaps, but it worked. I was impressed hearing the speakers again this weekend by the coherency with all three drivers.

The cabinets are high-density particle board and the finish is Formica. The woofer grill is burlap. I certainly wouldn't build them like that today but that's what I used back when I made them.

View attachment 5898

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"so I unwound the choke bit by bit until I reached the point where I could no longer hear the dip. I then measured the choke and unwound the other channel's choke to match. Not very scientific perhaps, but it worked"

As for as I concerned reality beats "scientific" every time.

jcwhite57 said:

Contacted Bil Legall and he gave me a reasonable price to replace the Carboneua surrounds. After removing them from the cabinets they were in worse condition than I thought Both woofers surrounds were punctured and were detached from the frame in places. Massive air leaks. On top of that one of the woofers was out of phase. Looking forward to re-installing them.

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I am sure you will be surprised by the improvement in sound with new surrounds.

jcwhite57 said:

"so I unwound the choke bit by bit until I reached the point where I could no longer hear the dip. I then measured the choke and unwound the other channel's choke to match. Not very scientific perhaps, but it worked"

As for as I concerned reality beats "scientific" every time.

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Do you recall what the inductance and resistance is from your measurements?

JimPA, eBay seller describes these as Vifa Peerless X5905 Danish made 6 1/2" speaker from the closed "Fried " Speaker Company in Michigan. These look similar to the Gefco you posted a picture of.
https://www.ebay.com/itm/Pair-Vifa-Peerless-X5905-Danish-made-6-1-2-speaker-Midrange-Woofer-Denmark-NOS/192897066834?ssPageName=STRK:MEBIDX:IT&_trksid=p2060353.m1438.l2649

These appear to have the double magnets and measure 6 9/16" outside diameter. I'll measure the OEM drivers when I get home.

Do you think these are the correct driver and fit my C3L cabinets?

Jimmy

I’m certain this is the same driver and ordered a set. Seller claims he has cases of these. I’ll update when I install them.

jcwhite57 said:

I’m certain this is the same driver and ordered a set. Seller claims he has cases of these. I’ll update when I install them.

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Those are the Fried Gefco C6 drivers.
I contacted who I believe is that same Ebay seller a few years ago.
I inquired if he had any of the Gefco drivers and Hiquphon tweeters,
His reply was no.

I built new enclosures for the C6 Gefco drivers.
They should fit in the C3L enclosures.

I know one of the former owners of the Fried Products had a run of those made after Gefco closed their doors
Misco may have built the last batch of C6, O6 and A6 drivers for Shayne.