Hi FullRangeMan ~ It is equally nice to read all of your posts, always interesting insights and highly informative.
Yes, I was into audio beginning when I was 12 years old. My uncle put together a lovely system using Wharfedale co-axial drivers and of course a tube amp, this was many years before Solid Sate circuits were invented. I heard it and was transformed. 16-ohm drivers ruled the day and were a perfect match for low watt amplifiers.
The Lowther PM5 Alnico/Ticonal drivers are 16 ohm, a very important factor in their satisfying performance with my 2 watt Yamamoto flea amp. I had Shigeki Yamamoto replace his standard 8-ohm output transformers with 16-ohm transformers. I ordered the amp directly from him in Japan. Shigeki agreed that the larger transformers would be a much better match for the 16-ohm Lowthers. That is why I suggest that a little research is very helpful when putting together a small watt system. The payoff is the potential for a heightened 'you-are-there' ultra-dimensional musical experience.
Here are 3 interesting posts from the esteemed Nelson Pass that go back to 2009 on the DIY forum. He also uses, or at least used, the Lowther PM5A with his 5 watt amplifier in large open baffle panels:
"I have just finished a detailed subjective comparison between the
PM6A, PM5A, and PM4A, all 16 ohm and all Alnico, in my Big Open
You may recall that they are very similar except for magnet size,
with the PM4 having the most monstrous magnet (It requires a big
butt brace) and the PM6A having the smallest.
All the drivers have comparable response curves in this system, where
they are crossed to a 15 inch woofer at 150 Hz and 12 dB/oct. All have
a mild notch filter at 4.5 KHz, -3db.
The PM5A edges out the other two for upper midrange naturalness,
but the PM4A had the older whizzer design without the rolled edge,
and I speculate that it would have equaled or perhaps bested the
Nevertheless, the PM5A is the one that sits in the system day-to-day."
"Typically I don't need more than 25 watts for the low end, and I usually
use about 5 watts for the top end.
Two drivers, FR and woofer.
Filtering, simple 12 dB/oct and a simple notch - anyone can do it.
Small footprint.... You got me there, but the BLH's that I like tend to
be on the large side.
Anyways, I like the lack of internal box reflections and the way a dipole
"illuminates" the room."
"There are a lot of possibilities, but the ones that work out the best
all seem to have high efficiency, light cones and low resonant frequency
down around 20 to 30 Hz. The inexpensive Eminence 15" alpha
and beta are good candidates. Martin King likes the alpha; I have
tried and liked the beta.
I biamp with an active crossover, and I can also EQ the bass response
which helps a lot. Given that, there a large number of woofers that will
do the job, and I have been able to get satisfactory results from SEAS,
PHL, Polydax, Vifa, and Fostex, and OEM parts out of Taiwan."
I don't use a notch filter on the Lowthers. Also, not having the resources or space that Nelson has I used what I had on hand to combine with the Lowther and Yamamoto. I stayed with it continuing to research and experiment, and I am happy to say that I am now in love with what this system delivers in musical bliss.
Merry Christmas, Merry Solstice, Happy New Year to all our friends on audio circle ~ Richard