Yes both they're Dipole woofers, and the LO series (underhung coils) are made to work in OB without a major need for dsp, and active EQ, that's why the QTS is fairly high.
AE TD15M, well from some examples seen/measured it has a real xmax of +/-3mm before the surrounds start stretching, beyond that point it is not really linear anymore, as a Klippel test would tell.
They used to be quoted +/- 3mm xmax, when Nick Mckinney sold them under the Lambda name.
Depending on how low you want to go?, and desired spl?, you will likely use EQ down low to compensate for the dipole loss, eating up excursion.
So you might be better served looking at they're X or LO/dipole series, but that is just my view
The B&C 12MH32 is a favorite of mine. It doesn't go as low as some of the others (about 60 hz vented), but it has very accurate midbass and a sophisticated biased split winding motor, allowing it to compete with the top end reach of a 10" while having the punch of a 15" midbass. The motor is very quiet on this driver. Mms is in the 50s and yet its a stiff and well dampened cone. The VC is vented everywhere, even under the spider which is uncommon for a pro woofer costing $230. Likely the best easy to get ahold of dedicated midbass which can do all the things some more expensive drivers can. Playing a snare drum through this driver will make you jump out of your seat. The dynamics capability is right up there with anything else costing several times more.
If high QMS is your ultimate goal, it means the driver has no shorting rings, no copper in the gap, copper-sleeved polepieces etc. Using the simplest polepiece materials available etc.
Meaning no inductance control. Variable Le over Excursion, and higher distortion in general, all things being equal (which it never is
) None of those are good things, so as Profiguy stated, within reason, in a woofer i might add.With of course a fiberglass (heat insulator) or similar voice coil former, that focuses all the heat in the VC winding., which has pluses and minuses too, depending on how the driver is designed.
Look at Klippels Distortion charts and how much of it is contributed by variable Le for example.
Also if a driver has QMS and CMS given, and the rest of the usual T/S param. RMS will be given.
Some of the best midranges I've encountered has a low Qms and high Rms value too so it depends.
Same goes for tweeters.
Imo you want most of the restoring force in the spider, not the surround.
But again it depends on the driver, design, frequency range and intended use.
Rms : Mechanical damping in [kg/s] (the unit for friction), (or
[N*s/m] gives you the mechanical damping
of the diaphragm arising from mechanical friction, including
the resistive part of the radiation load. Rms can be compared
to Rme, and Rms is similarly related to Qm. For woofers this is normally desired because the
suspension then operates closer to a perfect spring.
To chase a single T/S parameter as the goal of sound quality is likely not going to give you what you are looking for.
But that is just my opinion and experience.
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Hi all. i have quoted the opinion of Mr. Bernd Timmermanns - here in Germany with a quite good reputation about what he is talking about in the DIY audio scene. I use now for the mid bass the Celestion FTR15-3070C, no very low Rms and very high Qms, but with very low distortion level in the kick bass and lower midrange and i am completely satisfied with the performance even at lower listening levels - but for me the real fun is to listen with higher listening levels anyway
I think the Rms thing can be used to make a choice between similar drivers - Fc,, Sd and so on - for High Fidelity purpose take the one with the lower Rms level, but only when the difference is really significant, the good value half of the other value, with 10 percent difference there will be no audible effect i guess.
I think the Rms thing can be used to make a choice between similar drivers - Fc,, Sd and so on - for High Fidelity purpose take the one with the lower Rms level, but only when the difference is really significant, the good value half of the other value, with 10 percent difference there will be no audible effect i guess.
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Thanks Arez for great info!If high QMS is your ultimate goal, it means the driver has no shorting rings, no copper in the gap, copper-sleeved polepieces etc. Using the simplest polepiece materials available etc.
Meaning no inductance control. Variable Le over Excursion, and higher distortion in general, all things being equal (which it never is
With of course a fiberglass (heat insulator) or similar voice coil former, that focuses all the heat in the VC winding., which has pluses and minuses too, depending on how the driver is designed.
Look at Klippels Distortion charts and how much of it is contributed by variable Le for example.
Also if a driver has QMS and CMS given, and the rest of the usual T/S param. RMS will be given.
Some of the best midranges I've encountered has a low Qms and high Rms value too so it depends.
Same goes for tweeters.
Imo you want most of the restoring force in the spider, not the surround.
But again it depends on the driver, design, frequency range and intended use.
Rms : Mechanical damping in [kg/s] (the unit for friction), (or
[N*s/m] gives you the mechanical damping
of the diaphragm arising from mechanical friction, including
the resistive part of the radiation load. Rms can be compared
to Rme, and Rms is similarly related to Qm. For woofers this is normally desired because the
suspension then operates closer to a perfect spring.
To chase a single T/S parameter as the goal of sound quality is likely not going to give you what you are looking for.
But that is just my opinion and experience.
I while back I built a pair of 15" woofers and for that project, I read a lot of woofer specs from a lot of manufacturers. The Rms values (from specsheet or calculated from other values) range mainly from 1 to 10, a few up to 15 and one extreme being ~20. In absolute terms, what would be considered a good, low value?
I understand that Rms alone does not speak about quality. For example Dayton Audio RSS-line is usually highly regarded, but all of their 12" and 15" woofers have Rms >10. The woofer I ended up choosing has Rms of 2.31, but that was not a factor in the decision.
I understand that Rms alone does not speak about quality. For example Dayton Audio RSS-line is usually highly regarded, but all of their 12" and 15" woofers have Rms >10. The woofer I ended up choosing has Rms of 2.31, but that was not a factor in the decision.