A Bold Speaker Project by Tom Perazella

December 9 2017, 06:00
In May 2016, following the Munich High End show, audioXpress published a short article preview of SB Acoustics' highly anticipated new drivers, including the brand's flagship TW29BN high-end beryllium dome tweeter, part of its Satori top performing range. The new drivers, all designed in Denmark and manufactured in Indonesia, also included new midrange and midwoofer drivers using new proprietary cones made with Egyptian papyrus fibers, available in 5" to 9.5" sizes. The new high-end Satori range is the visible result of an intense R&D effort that started in 2009, when Danesian Audio in Denmark became 100% owned by Sinar Baja Electric, focusing on the evolution of the SB Acoustics catalog.  The SB Acoustics products can be used in many different applications, but they remain at the top of the scale in terms of quality.
Shortly after news of the new Satori drivers was out, I received a message from Thomas Perazella, an esteemed frequent contributor to audioXpress, with an idea for a new speaker project, which could benefit from using the new Satori drivers. "The concept for this design was based on the Mach 17 speaker built by Waveform Research of Canada starting in the 1990s. Founded by John Ötvös, this company produced a speaker that minimized diffraction problems by having the midrange and tweeter in an enclosure shaped like an egg. Standing waves in the separate bass cabinet on which the egg rests were minimized by the truncated pyramid shape. It garnered rave reviews while in production," Perazella explained.
His proposal was to apply his experience as a speaker builder to create his own version of the three-way configuration, including a top "egg-designed" speaker featuring the new Satori drivers, with an additional low-frequency "base." We approached SB Acoustics with the idea for the project, which received immediate enthusiastic support!
For his "egg" speaker project, Perazella specifically requested the new TW29BN beryllium tweeters, and the 6.5" MW16P-4 midrange, for its smooth off axis response above 2 kHz. As Perazella explained, "I will not have a problem with linear volume displacement with the 16P on the low end because it will only be used above 200 Hz with the low end provided by two Dayton RSS315HO-44 12" woofers in a separate trapezoidal shaped sealed box base." And to get the most out of the design, Perazella requested the 16P with the white Egyptian papyrus cone, to contrast with the black light metal finish planned for the set-inspired by the Buick Verano that his wife owned. "I already have a sample of a black automotive paint on a piece of MDF that I supplied to the shop and the results were great. It will be a difficult construction project but very interesting for the readers," Perazella wrote with enthusiasm in December 2016.
These are photos of the Satori drivers that Tom Perazella received. This is the TW29BN Satori Beryllium Tweeter
And this is the MW16P-4 Satori midrange. Click any of the pictures to access Vance Dickason's explications in Voice Coil magazine.
For our readers interested in more detail, Vance Dickason characterized samples of the SB Acoustics TW29BN high-end beryllium dome tweeter and the MW16P-4 midrange, in Voice Coil's Test Bench. The Test Bench explication for the midrange was published in January 2017 and the tweeter, in February 2017. Both articles are now online. Just click on the respective images above.
In March 2017, following the commercial launch, Perazella received his drivers. "The drivers arrived today! Thanks. They are beautiful. The white cone will be very striking against the black metallic automotive finish that will be used on the housing. The construction of the housing will be the most complex wood working project I have done. To build the egg-shaped housing, 18 slices of ¾" MDF of different diameters will be used," he wrote.
Following months of intense work on building those cabinets, Perazella sent us an update on the design in September 2017. "The SB Acoustics midrange and tweeter both have the same radiation pattern at the crossover points. I will be doing a passive second-order LR crossover so that the speakers can be used with a single amplifier. However, the crossover will be external and have the ability to make connections to the drivers in a tri-amped mode. That way I can compare the conventional passive relatively shallow slope crossover to an active sharp slope crossover implemented with DSP so there can be time correction as well. It should be an interesting comparison."
The egg speaker with drivers, and woofer base. The top features the SB Acoustics Satori beryllium tweeter, and the SB Acoustics 6.5" Egyptian papyrus Satori midrange. The speaker base features two Dayton Audio 12" Reference Series HO DVC woofers.
Detailing the wood work, he called it "the most complex and difficult wood working project I have ever done," Perazella explained that not only is the egg shape with a flat front "very difficult to do but the truncated pyramid base for the woofers is crazy. I wanted it to have a visually small front so I made the front and rear smaller than the sides. The base is therefore rectangular in shape. At the top, I wanted it to be square with rounded corners to better blend with the egg shape. As a result, there is not a single 90-degree cut on any of the pieces. I had to do a lot of math to determine the sizes and angles of the pieces and then get a digital protractor to accurately set the blade angles on the saws."
In October, Perazella wrote back with another encouraging update. "I got the painted eggs and bases back today and just had time to assemble one of the eggs. I'm including a photo." He also confirmed the speakers would be unveiled at a meeting of the DC HiFi Group, and make it to the group's booth at the Capital Audiofest 2017 the following weekend.
The eggs at the recent Capital Audiofest, the mid-Atlantic's largest high-end audio show. Standing room-only auditioning.
Following the debut at Capital Audiofest 2017, we asked Perazella to send us his impressions of the unveiling at the show. "After a year of design and construction, my version of the "egg" speakers were finally shown at Capital Audiofest, in the DC HiFi Group room. They received rave reviews with comments like "the best sound in the show," "better than the $1,000,000 room," "more coherency than my electrostats," "better sound than any of the $30,000 to $40,000 speakers I have heard," "pinpoint imaging where every player can be positioned as they move about the stage," "seamless from top to bottom," "detailed without being harsh," "they are works of art," and more. The true test of how people feel is if they return to listen further. Quite a few people did return, some coming back three or four times and spent quite a bit of time. At some points in the show there was standing room only to audition."
Here is another astonishing view of the speakers in the DC HiFi Group room, as presented during the Capital Audiofest 2017 show. Photography courtesy of Paul Elliott. 
Perazella's complete project will be detailed in an upcoming article of audioXpress. You will not want to miss the details of this extremely complicated project. Stay tuned!

This text was originally published in The Audio Voice #157 weekly newsletter (November 2017). Subscribe here.
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