Fried Model B/2 Speakers


Everything you always wanted to know about this speaker, and then some.

Rebuild project completed 6/2007.

 

 Above: The Fried Model B/2 along with some of its contemporary competitors.  Left to Right: Fried B/2, Fried Model B (the B/2's predecessor, also used as satellite for the  Model H), Rogers LS3/5a, and JR149.  Note that except for the B/2, all of these speakers used the KEF T27 tweeter and KEF B110 mid-woofer.  Click photo to enlarge.

Above: Same speakers, with grilles.  Click to enlarge.

Introduction

The Fried B/2 is a mini-monitor speaker, marketed in the late 1970s, starting in 1978.  It competed in a market segment that included the Rogers LS3/5a (link to more info), JR 149 (link to more info, and more here), and KEF 101, among others.  It was sold both stand-alone, as the Model B/2, and with a separate dual channel, single box, transmission line subwoofer called the Model T.  As a package, the three piece satellite-subwoofer combination was called the Model H/2, shown below.  It was sold both in assembled and kit form.  One dealer (Sonikit)'s prices in 1979 for the B/2 were $600/pair assembled, $420/pair for the kit version including cabinet kits.

 Above: Photo of complete H/2 system from Sonikit (Fried retailer) marketing brochure, 1978.  The satellites were also sold separately as Model B/2, and sub sold separately as the Model T.

Marketing materials

The Fried sales brochure for the Model H/2 is shown below, click on each page to enlarge.

Above: Fried H/2 brochure, page 1, click to enlarge.

Above: Fried H/2 brochure, page 2, click to enlarge.

Above: Fried H/2 brochure, page 3, click to enlarge.

Above: Fried H/2 brochure, page 4, click to enlarge.

 

 

Above: Fried B/2 as shown in 1979 Sonikit brochure.  Click to enlarge.

Above: Fried Model T subwoofer in 1979 Sonikit brochure.  Note that Sonikit re-engineered the Model T subwoofer into 2 vertical transmission line cabinets, verses the original Fried design of two horizontal T-lines in one single cabinet.  Click to enlarge.

Click here to see the entire 1979 Sonikit brochure in PDF format - includes the full line of Fried speakers.

History

This speaker was an evolution of the original Fried Model B, which used the same cabinet but included KEF drivers (B110 mid-woofer and T27 tweeter).  The B/2 used a Dalesford D30/110 mid-woofer and Dynaudio D-28 tweeter.  Both of these speakers were subsets of larger systems, starting with the 1977 Fried Model H (Link to more info here) which consisted of two Model B satellites and single dual channel subwoofer, connected to an external crossover in a separate box (no crossover was in the speaker cabinets).  In the next incarnation of these speakers, in 1978, Fried replaced all of the drivers and crossovers, calling the new components the Model B/2 satellites, Model T subwoofer, and the combination of these two as a complete system was called the H/2.  These new speakers used all new drivers in the same boxes as the previous generation.  Where the Model H (and Model B) used all KEF drivers, the H/2, B/2, and T used a Dynaudio D28 tweeter and Dalesford Bextrene coned mids and woofers.  The Model B/2 used the D30/110 5" midrange (same size as the KEF B110) and the Model T subwoofer used the Dalesford D100/250 10" driver, increased in size from the 8" KEF B200 SP1022 used in the original Model H.  On a parallel product track, the Model M was derived from the Model H, in response to requests for a more tradional stereo pair of speakers, instead of the satellite-subwoofer setup of the Model H.  The Model M's consisted on the Model B satellite mounted atop one single transmission line woofer (half of a model H subwoofer).  When the H/2 was introduced, the M/2 was similarly upgraded with the new Dalesford and Dynaudio drivers and crossovers.

Reviews

Above: Sensible Sound review of the Fried Model B/2, 1978.  Click to enlarge.

 

Above: Follow-up review by Sensible Sound, summer 1979.  Cribbed from the Sonikit brochure above.  Click to enlarge.

 

The drivers

The Model H/2 used a Dalesford 5" bextere cone mid-woofer (model D30/110) very similar to the KEF B-110 it replaced in the original Model B.  The tweeter was a horn loaded soft dome unit by Dynaudio, Model D-28 (so named for the 28mm diameter).  This tweeter has exceptional power handling capability, and allowed Fried to use a first order high pass crossover on the tweeter.  It also had a sticky coating, so dust on the dome shows up in the photos.

Above: The Dalesford D30/110 mid-woofers used in the B/2.  Note that Fried applied a label to the rear of the magnet, but left the Dalesford model number on the drivers.  Specs below.  Click on photo to enlarge. 

 

Above: Data sheet for all Dalesford drivers, including the D30/110 mid-woofer.  Click to enlarge. 

 

Above: Dynaudio D-28 tweeters used in B/2.  Note again the Fried label on the rear of the driver.  Specs below.  Click photo to enlarge.

 

Above: Spec sheet for the Dynaudio D-28 tweeter.  Note the almost completely flat impedance curve, as the resonance is damped with ferrofluid.  Click to enlarge.

 

The crossover

 Above: Crossover schematic for Model B/2, based on examination of 2 pairs of speakers.  It is basically a 2nd order filter on the mid-woofer, with impedance compensation, and a first order filter on the tweeter.  Note that one pair of Model B/2's which I examined used two 0.25mH chokes in series for the woofer choke, the other pair used a single 0.5mH choke.

 

Click photo to enlarge.

Above: Terminal plates for the B2, showing the crossover side.  The assembly on the left is the stock crossover - note the electrolytic caps in the low pass section, and film caps in the high pass.  Resistors are 5W sandcast and 2W carbon.  Note the two chokes in series to get the desired value.  In another Fried B/2 pair, assembled from a kit, the crossover uses a single 0.5mH value instead the two 0.25mH series chokes in these speakers.  The crossover on the right has been upgraded, replacing caps with Solen polypropylene (reusing one film cap in the bass section), and replacing all resistors with Mills 5W wirewounds.  The stock banana jacks and fuse were retained for a stock look.

 Click photo to enlarge.

Above: The crossover/terminal plates from the outside.  Note the plate is a thin plastic laminate sheet with engraved lettering.  The serial numbers are simply self adhesive Dymo-type labels.  Note that the serial number starts with B2, but the terminal plate only indicates Model B, not B2, suggesting that Fried was using up existing inventory.  This also points to the fact that Fried changed and improved their products quite frequently.

 

Above: Fried B/2 crossover transfer function for the woofer section.  This measurement is made at the driver terminals with the driver connected to the crossover, showing the frequency response shaping effect of the crossover (NOT the frequency response of the speaker, shown below).  Note the -3db point of about 3900Hz, and the slope is 2nd order.  Other than a very slight broad dip centered at about 500Hz, there is almost no EQ done by crossover.  That is in sharp contrast to another popular mini-moinitor of the same period, the LS3/5a, which used extensive frequency response correction by the crossover, shown below.

 

Above: transfer function of LS3/5a woofer section.  Note extensive frequency response tailoring done by the crossover to compensate for anomalies in the driver response.

 

Above: Crossover transfer function of the Fried B/2 tweeter section.  Note the 3db/octave slope above 2K, with a steeper slope below that point, and the -3db point of 5,350 Hz.  The high frequency rolloff above 15K is an artifact of my measurement system.

The cabinet

The factory made cabinets for these speakers were primarily particle board, with walnut veneer on the sides, top and bottom.  The front edges had solid walnut stock trim to allow the 3/8" roundover, done for diffraction purposes (and an upgrade from the previous version of the Model B).  The quality control for the cabinets was not great, as the faces of these speakers has been beltsanded, leaving sanding marks against the grain and an uneven edge.  In addition, the recessed mounting holes for the mid-woofers were too shallow to fully recess the drivers.  When I refinished the speakers, after re-sanding the faces smooth, I re-routed the 3/8" roundover to get a smooth edge and I re-routed the driver recesses to the correct depth, using a template and guide bushing.  Cabinets were then stained the original walnut color, given a spray coat of polyurthane, and the faces painted black (although the originals simply had the particle board stained walnut color).  The originals had self-adhesive velcro strips for the attachment of a foam grille, which I did not replace, instead using snap-in grille connectors.

One note of interest: the back of the cabinet is secured with four screws, but on closer examination, the back is glued in, visible from inside the cabinet.  My conclusion is that the terminal  plate/crossover was attached to the back of the speaker while it was separate from the rest of the cabinet (for ease of assembly), then it was glued into the box, and the four screws were used to secure the back while the wood glue dried.

 Above: Refurbished and refinished cabinets, ready for assembly.  Click to enlarge.

 

Above: Fried cabinet plans for the Model H satellite, same as the Model B and B/2.  Click to enlarge.

Grilles

The Fried B/2 was originally sold with a black open cell foam grille, although I understand that Bud Fried listened without any grilles.  It was fastened by self-adhesive velcro attached to the face of the speaker.    Unfortunately, obver the years, the foam deteriorates and falls apart and most of the Fried speakers from this period that I have seen are missing the grilles.  I was lucky to get a pair of the foam grilles with this pair of speakers, and although they were falling apart, I was able to replicate the look of the grille with traditional wood-frame and cloth construction.

For anyone seeking to re-create the foam grille, its dimensions are 7 3/8" wide, 11 3/8" tall, and 7/8" thick.  The edges of the foam have a 3/8" roundover (the same as the walnut cabinet).  The logo badges are mounted in the lower left corners of the grille, 5/8" from the left side and 5/8" up from the bottom edge of the grille.  The following does not apply to the wood-framed replacements, but just to be complete,  the original foam grilles had a recess on the back, 3/8" deep and 5 1/4" wide by 10" tall to provide clearance for the drivers.  Note also that I lined the inside of the wooden frame with felt to help minimize diffraction problems from the grille frame, but it is so deep that it should be removed for serious listening, and will have a much more pronounced negative affect on frequency response than Fried's original foam grilles.

 

Above: Grille frames assembled.  Click to enlarge.

 Above: Grille frames painted.  Click to enlarge.

 Above:  Grilles completed.  Click to enlarge. 

I looked for a grille cloth that matched the look of the foam as closely as possible, and found some Magnepan black grille cloth left over from a Linkwitz Thor subwoofer project (link here) that matched the textlook quite closely.  I also removed the Fried logos from the foam grilles and glued them to the replacements.

 Above: Completed B/2 speaker with replacement grille.  Click to enlarge.

 

Conclusion: Refurbished Model B/2

 

Above: The refurbished Fred Model B/2, sans grille.  Click to enlarge.

 

Above: The B/2, rear view.

 

Frequency Response Measurements:

Above: B/2 frequency response, measured at 50 inches.  Note that I have 2 pairs of these speakers, and measured the response of all 4 woofers - all exhibit the same bump at 1KHz. 

 

Above: B/2 low frequency response, measured near-field.  Note the -3db point of about 75 Hz.

 

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