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Bringing the Aviatrix MT back.


Apr 5, 2022
I've always been a big fan of Curt Campbell's Aviatrix design, both the MT and MTM (never built the MTML/MTL's). Back in 2010, when he first made the design available (he gets my award for "Most Selfless Designer), I built a MTM and two MT's for a LCR frt., scratch building the boxes as this was before the flat-packs were avail. and have been using them ever since.
I moved into a bigger place this year and wanted a little more SPL up frt that the MTM's provide, so I robbed the MT's, bought two more woofers and the X-over parts needed for 3 MTM's.
Although I didn't really need more book shelves, the MT boxes were too nice to leave sitting around empty, so what to do?

RST28F Apprehension (A little recap.)

When Dayton Audio replaced the beloved RS28 (both the F and A) with the RST28 around 2017, the thinking was maybe they would be a "drop-in" replacement. Vance Dickenson measured the RST's and thought so, but as other designers started to look at them, doubts arised. The late Jeff Bagby in his rather humorous "carpet floor" measurements thought they looked close enough to redesign them into his, now classic, Continuums, but in the end he eschewed them for Morel's. Paul Carmody did much the same thing with his Event Horizons's. The first problem folks encountered was build inconsistenceis, level matching a pair was nigh-on impossible and many were sent back the Parts Express. To their credit P.E. (Dayton) sorted this out, but compared to the original, the raw data of the RST was a little worrisome, a higher FS and some peakyness. Some Designers worked with them (Dan Marx and Impulse Audio), but both commented they wouldn't use the RST's again;

P.E. introduces the Samba kit, but Erin doesn't think this Brazillian Tangos.

Erin (Erin's Audio Corner) passed his review/test results here to ASR, so no need to go into those here, but the question remained, How good/bad are the RST28's and as I read, I wondered if the "in-house" designs w/ the RST28 were best passed on.

If anyone can, the Magic Man can.

In 2019, P.E. reached out to the Aviatrix original designer Curt Campbell and asked if he would be interested in doing a X-over update for the Aviatrix/RST28 and in 2020, they released their Aviatrix MTM kit w/ the RST28F. The X-over, remarkably simular to the original, is listed on the P.E. site and fortunately for me, he also redid the MT (posted here);
I read the reviews at P.E., but they tend to be rather ebullient.

I am happy to report they sound as good as the originals and now my confinance is such that I think the MTM's must as well.

The Aviatrices are well represented on the Web, so no need to expound on their sound, but I would like to make the case as to why I think they are the best value in a DIY kit that comes with flat packs.

Value - At $300 a pair, they come as a very complete kit w/ binding posts and even stuffing.
The MT's - Curt is known for his simple, low part count X-overs and my cost for the drivers and X-over components (excluding the enclosures) came to $200 for the pair.

Quality - Refering to the flat packs here. I've always enjoyed assembling the P.E. (Dayton) boxes. They are very precisely cut and a breeze to assemble.

Looks - One of the things Curt did with original design, was try different box diamensions is an effort to strike the best compromise of low height, when placed horizonaly under a TV and being aesthetically pleasing. I think his efforts payed off.

Versatility - The X-over point for both the MTM and MT is very low, in the 1K to 1.2Hz range. To my knowledge, this still the lowest of any 5.25 inch woofer(s) to a 1 inch tweeter making both vertical and horizonal placement an option w/ minimal lobbing effects. I will also add that these are sealed speakers making "up against the wall" or even cubbyhole placement viable.

Some cons,

Some reviewers have commented on the 1/2 inch MDF material and this does seem a little thin to me. It would be little trouble to add one or two cross braces (dowels), or to do what I have done in the past, coat the inner box walls w/ Durham's Rock Hard Water Putty.

And the biggest con in my view, the MTM kit is only avail. in pairs, requiring the purchase of two kits for a LCR frt. One option for a 5 channel home theater appication would be to use the drivers and box of the one leftover to scratch build two MT rears. The only more parts that would be needed would be one tweeter and a few X-over parts.

There you have it, I've made my case and I hope this opens up another option for any considering a modest DIY speaker build.

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