SBAcoustics, MTM, built by George, US
Copyright 2018 © Troels Gravesen

Hi Troels,
I've completed the SBA MTM-16. Many thanks as always for your ongoing inspiration, output, emails, and contribution to the DIY community! Here's my review on these great sounding speakers. Enclosed are building/testing photos.
For years, I've used the D'Appolito based Adam S3A as nearfield monitors for my piano recordings. I recently built the Ellam D'Appo and now SBA MTM-16. Joseph D'Appolito studied and designed speakers locally in the Boston area. D'Appolitos present a nearfield image at farfield distances. It's like listening to monitors at a distance. This imaging offers great immediacy when the speakers are pointed at you in the horizontal plane. They have wide horizontal and narrow vertical dispersion characteristics. However, when listening outside the horizontal plane or "sweet spot," you lose the magical immediacy and near field directness. D'Appolitos sound great in wide (versus narrow) rooms, and the vertical null zone is also effective in minimizing ceiling, or floor reflections.
Instead of floorstanders, these speakers were made to sit atop a stereo pair of Scan-Speak 32W subs. Maintaining front baffle width, the height was decreased, and the depth was increased to yield 40L. The cabinet measures 29.5in x 9in x 15in. Instead of 20mm Baltic birch, 25mm was used on the sides and back, and 38mm black MDF for the front baffle for a strong enclosure. Bevelling the edges maintained a 8.5in baffle width. Vibration damping sheets, felt, and 30mm acoustilux were used as directed. Jantzen kit components were used. The crossover is accessible via the removable bottom panel. The Baltic birch cabinet was finished with GelStain. Lacquer toner spray brought out the color saturation, contrast, and detail in the wood. The front panel was sprayed with black primer and lacquer. The entire cabinet was finished with 6 coats of polyurethane. The build took 65 hours.
Based on nearly identical parameters, I thought the Be tweeter could be a "drop in replacement" for the standard TW29 tweeter. So when the MTM first appeared with a standard tweeter, I asked Jantzen to substitute a Be tweeter instead of 'more of the same' standard tweeter. They put my order on hold to first ask you (blame me for the extra work;). I really wanted to hear this much anticipated Be tweeter. I kept the 2.2 and 2.7 R on the crossover for versatility. Indeed, the 2.7 Ohm has a flatter response with the Be version.
After 20 hours of break-in, it was only fitting to compare the SBA MTM 16 with the Ellam D'Appo. I've been very impressed with the Ellam D'Appos. The 15W mid has exemplary  clarity, smoothness, detail, and potent bass. Surprisingly, the 5.5in Ellam D'Appo delivers more bass at half the volume than the 6.5in SBA MTM. The 15Ws move more air than MW16Ps at the port. The price is efficiency, as the Ellam D'Appo is 4dB less efficient than the SBA MTM-16s. As for the midrange, the light cone weight of the MW16P produces faster transients and more transparency compared to the heavier coned Scan-Speak 18W and 18WU midwoofers in my other speakers. The lack of compression in the mids at high volume is also impressive. The treble is where the MTM's higher sensitivity renders tremendous inner detail with more clarity, texture, and dynamics over the Ellam D'Appo. The Be tweeter offers more accuity, timbral definition, air, and blacker background without smear or veiling of detail in highs. Overall, the soundstage is open, airy, spacious.
Like voicing instruments, I tend to voice speakers with different caps for based on analog/digital sources, sold-state/tube amplification, ICs, and genre of music. These new Alumen Z Caps render coherence and transparency, without sacrificing detail nor dynamics. The Alumen Z Caps have more "analog" warmth than Rike S-Caps or Mundorfs that I've used. Regarding the crossover, the MTM's presence in the 700-1000Hz region makes most music engaging. However, on some piano recordings too much timbral highlights lead to some stridency on solid state amps. Perhaps the LCR would've been a nice switchable option. However, this didn't occur on tube amps.
Sources: Rega RP6 turntable with a Dynavector 10X5, Denon 3930ci CDP, and Yamaha CDR1000 CDR. 
Tube Amplification: Custom Don Sachs Model 2 6SN7 Tube Preamp with tube rectification, and 6SN7/KT88 push-pull Amp; 65W. Manley Chinook Phonostage, DIY Aikido PH-1. 
Solid State Amplification: Odyssey Tempest Extreme Preamp and Odyssey Dual Mono Stratos Amp. Behringer iNuke DSP3000 Amp @60Hz Subwoofer Amp.
Interconnects: DIY Duelund DCA20 Copper Cotton Oil wire soldered to RCA connectors. Speaker wires are DIY Duelund DCA12, 12AWG Copper Cotton Oil wire soldered to spade plugs. Snake oil or not, I've discovered the Duelund DCA wire conveys more detail, transparency, and extension than my neutral Shunyata Venom ICs.
Speakers: SBA MTM-16. Ellam D'Appo. DIY 13" 3-way Visaton TIW300 + Scan-Speak 18WU/8741 + 66000. DIY Scan-Speak Classic 8" 2.5-way 21/8555+18W/8545+98000, Scan-Speak 13in. 32/4878T00 stereo subwoofers.
The SBA 16MTM produces a neutral, coherent, detailed, dynamic, open, airy, spacious sound. These speakers are equally suited for analog or digital sources, and solid state or tube gear. The high efficiency makes them ideal for my KT88 push-pull amp as the difference can be heard. The SBA 16 MTM is an uprade from the Ellam D'Appo offering greater transparency, detail, dynamics, and holographic imaging. The SBA MTM excels in textural and timbral information. These observations were made without the subwoofers. The MTM can stand alone without subs, however, in a large room, subs offer extension below 40Hz. In the pipeline are the MUN17, ATS-4, and Scan-Speak Ophelia speakers.
George (U.S.A.)