Mike's MTM - Good Progress

Remember my MTM of ER18RNX and 27TDFC, configured for my 300B SET amp? Well here's a pic (I hope) of the finished article and notes on the sound.
They have also acquired a name; Tau. From the tulip association, see the detail in the picture; and also tau for time constant and these have 3 of them (think about it ....).

Comparisons are with my previous speakers; IPL S3TL transmission lines; nearest equivalents are Ruark Talisman II's which use virtually identical drivers but the IPLs are better.

The Tau has excellent dynamics, far better than the IPLs. This is evident in many ways, not just bass and slam.
Also, bass is better; tighter, and better transient response. Tuneful, detailed bass.
The dynamics and bass together give very much better rhythm! The system really plays tunes far better, it's that simple and it's *big*.

Detail is much improved.
Sound is very clean with it; it's not harsh detail.
I'm hearing a lot more in the music. Focus of singers is improved.

Frequency range and balance seems good. Piano has more body to lower notes and chords (I guess I've already mentioned bass).

Tonality is very good and (sorry, getting b o r i n g) much improved. Slightly richer overall (lower mid range I guess), probably due to decent BSC. Bass is not overblown or heavy; treble seems in proportion. I have not yet measured them or tried Jay's voicing procedure but they are not far out already and I will try these things.

They now have about 60 hours use and seem to have settled. An issue with female vocals seems to have 'run out' if you see what I mean. This wasn't quite right .... freq balance a bit out, with soprano voice seeming to have too little fundamental and too much harmonics. Not bad at all, listenable but not right. It seemed to come in more after about 40 hours use - strange.
Anyway, I decided not to tweak until they had at least 50 hours.

So a few days ago I removed my 18 ohm + 15uF across the woofer which pulled the FR down a bit at about 1kHz, bringing (by simulation) the BSC in at the right point. Removing it was an improvement. Now, over the last 2 days, the problem has substantially gone (perhaps totally).
Favourite ladies are *singing*, and very well indeed too; Kiri te Kanawa, Rickie Lee Jones, Barbara Courtney King (Pastourelle), Karen of Capercaillie, Frederica von Stade, Trudy Kerr, Claire Martin, Nicola Hitchcock all tried today and are fine. Many, many more to try! There is more detail and clarity to voices, and presence .... it's just been a case of whether they sounded right.

I will try measurement and xover mods to find the optimum - but it's not far out now.

Orchestral music is sounding amazing; dynamic, dramatic, sweet, detailed, transparent, excellent tonality; all adding up to a fine musical performance and realism.
Living Stereo LP of Kondrashin, Rimsky K's Capriccio Espagnol is simply astounding; the dynamics, the many rhythms, tunefulness, focus of individual instruments, all excellent. Much, much more to the whole piece than with the IPLs.

I am of course over the moon about these speakers. I'm sure one reason for their success is the modelling of the bass with the effect of my amp in the model - I'm sure this has a lot to do with the bass.

Above all, it's due to the choice of drivers, and advice on crossover design. I thank Jay most sincerely for both! And of course Zaph for his test work on the drivers.

Next: I will measure and then 'voice' them. I have not got round to this yet cos when I get the house to myself ... I just want to listen!


  • my mtm 1b.jpg
    my mtm 1b.jpg
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Thanks for the compliment.
Yes, I did the woodwork myself and it was complex. The sides are laminated. There are 7 braces fitted, 4 full shelf, 3 half shelf (I'll post photos later). The front panel is 28mm thick.
I've been involved with wooden boats all my life so I've developed some woodworking skills.

Veneer is pippy oak which I find attractive.
The inlay was done my me, in marquetry. The picture was chosen by my wife and me, from a magnificent book The Tulip by Anna Pavord - tulips are my wife's favourite flower. The picture is 'Tulips and an Ichneumon Fly' by Joris Hoefnagel, about 1590. We think it works well.
The previous speakers had a traditional musical motif that also worked well.

Anyway you can see why it took some weeks to finish them, but I'm pleased with the result.