Mike's Project - MTM?

[Mike C]

To get a useful bit more efficiency with a narrow baffle, and allow some BSC, MTM (or TMM) seems useful.
As I usually listen alone and can arrange to be in the sweet spot, MTM may work OK for me.

One interesting speaker (no longer available) was the North Creek Catamount; I might have gone for that even though it's pricey by the time it gets to the UK.

Now I have a very specific Q about MTMs. They have a low impedance and often a fairly variable impedance, due to 2x 8ohm woofers in parallel and a single 8ohm tweeter. Low impedance and variable impedance are said to be 'bad' with SETs; but the Catamount is said to 'love' SETs, and Wayne's Eros is also said to work very well with a 300B SET. Against other MTMs (even one with the same bass drivers as the Catamount), I see comments like 'SETs need not apply'.

So, can a MTM work well with an SET? What do I look for in such a speaker to ensure it works well?

[Mike C]

In an attempt to learn something, yesterday I got out a spare pair of speakers and hooked them up in parallel with my main speakers, to give a low load impedance.
The mains are about 88dB; the added pair are much lower (just over 80dB I think); JR149s (nice small speakers).

With both pairs in the main room, I noticed very little difference in the sound. Needed to raise the volume control slightly.

With the JR149s in another room, they didn't sound very good. But the main speakers (in their room) sounded *fine*. Coupling and uncoupling the 2nd pair while listening to the main speakers only showed a slight difference. On uncoupling the 2nd pair, the main speakers seemed to get a touch brighter; however, when trying to match the volume in both conditions, I'm not sure that there was a tonal difference or was I just hearing a volume change?
I'd say that any differences in the sound:
both pair in one room, 2nd pair connected vs disconnected
and
2nd pair in another room, listening to mains only, 2nd pair conn vs dis;
any differences were so slight as to be upset by the volume change.

I tried considerable volume setting, to give above normal listening volume with both pairs connected; sound seemed *fine*.

This all encourages me that my amp should drive an MTM OK.

I also tried the JR149s on their own in the main room; OK, quite nice, but a bit bright (small speakers), perhaps a bit more detail but was it just the tonal difference? Hard to say. But the JRs were not as complete and 'sophisticated' as the IPL S3 trans lines with their bass. I find it hard to use hifi speak but that's how it felt to me.