Ellam dappo, built by George/US
Copyright 2018 © Troels Gravesen

Firstly, thank you for your advice to my many e-mails over the years. I applaud your work and contribution to the DIY speaker community. May you continue to be a beacon of creativity and inspiration.

I've been waiting years for a good 6/7" D'Appolito, so I settled for the smaller 5.25in Ellam D'Appo kit 4 years ago. When the SBA 16 MTM came out, I immediately placed my order, and thought I'd never build the D'Appo. However, I was pleasantly surprised from the moment I powered them as I had the proverbial "Wow" reaction. They sound very smooth and neutral.

At first, I tried the Ellam D'appo with reverse tweeter polarity, but heard a notch ~3kHz, perhaps the tweeter suck-out. So, I wired them with positive polarity as the article indicates, and since, I've been quite pleased. To my ears, D'Appolitos have a near-field presence to the sound which make them more engaging.

The cabinet is made from 3/4" Baltic birch. Finishing birch plywood is difficult and unpredictable, so 2 coats of dewaxed shellac was placed, followed by GelCoat, and a topcoat of polyurethane with light sanding between all layers. The enclosures measure 19"(H) x 8.5"(W) x 14.25"(D). Internal volume is 24L, minus bracing, vibration damping panels, and internal crossover yields ~22.5L net. Felt and Polyfill was added. Wiring was 14 and 16 gauge stranded silver-plated copper PTFE.

The 15W/8530K is a very smooth sounding driver with no nasty cone break up modes. The XT25TG-04 tweeter, which I had bought years ago on sale for $50 has been a wonderful surprise. The lack of adjectives describing the sound of this tweeter is an attribute to its very natural and neutral tonal/timbral balance. I have an extra 98000 tweeter as a back up to my all-Scan-Speak Classic 871 system. I thought that I might try it out, but I don't think I need to swap the XT25 tweeter for any reason listed above.

For the crossover, I chose the Mundorf Hepta Strand for the woofer coil, for its supposed holographic, 3-D rendering. I'm not sure if this is equivalent to Jantzen's Litz Wire? The Jantzen Superior Z caps are very neutral and spacious on mids. The Silver Z do a fine job of providing transparency and fine detail in the highs without any hint of glare. I haven't experimented with the tweeter resistor, as the default 2.7 Ohm gives seems to give a balanced harmonic structure with plenty of treble detail without screaming "look at my sexy highs." What also impresses me is how fast the break-in period is for the Superior Z Caps. 20 hours into it, I feel the sound is very mature. Mundorf Supremes take 150+ hours on previous builds.

Listening to these for the first time, I'm really surprised at how smooth the sound is on the ear, even at high volume. They sound larger than its apparent size as the 2 woofers yield an equivalent membrane area an 8" woofer. The sound is very natural. The voicing is warm, detailed, dynamic, airy, spacious, and refined. Perhaps the SBA 16 MTM might add dynamics, sensitivity, transparency with its LR2 filter over the D'Appo, but I don't think we're going to get more out of a 2nd/3rd order crossover. The SBA MTM or MUN17-3W will be next to find out...

I can't imagine how so many people are missing out listening to music on flat tablets and phones these days. Whenever someone comes over, people are mesmerized how full-spectrum speakers can reproduce music in such a convincing manner and deliver the visceral impact it deserves.

George (U.S.A.)