Size of Midrange Drivers

Of course every designer has different priorities, but one of Siegfried Linkwitz's top priorities in the Dvorak was radiation pattern control. His target radiation pattern called for fairly large diameter midrange cones.

Impact and dynamics are preserved when the loudspeaker system doesn't impose audible thermal or mechanical compression on the signal. Mechanical compression of midrange drivers shouldn't be an issue in a well-designed system, as the crossover should protect them from reaching their linear excursion limits.

Minimizing thermal compression is not necessarily a function of cone diameter; it is more a function of efficiency and the thermal capacities of the motor/voice coil assembly. Generally, the more powerful the motor and larger the voice coil, the less thermal compression. Obviously increasing the number of drivers reduces the thermal compression at a given SPL. (Thermal compression is a rather complicated subject and detailing it is beyond the scope of this post, so I'm painting with a broad brush here.)

I'm very much a fan of Linkwitz's work, and his designs combine excellent performance in many areas. In my opinion, radiation pattern control where his designs really excel.

Duke
dealer/manufacturer

Duke, midrange drivers in my speakers use ferrofluid suspension instead of spiderweb (to increase speed by lowering overall mass). Coils are oversized connected to flat ring that holds membrane (instead of dust cap).

http://www.enjoythemusic.com/superioraudio/equipment/1104/hyperionhps938.htm

I assume that oversized coil in ferrofluid has low thermal compression. I'm only worrying that ferrofluid will dry out one day.

The largest cone midrange I can find is in the Tannoy "Kingdome Royal" speaker.
It uses a "12in Dual ConcentricTM drive unit" with a tweeter in its center.
Now we're talking (where did I put that Tool CD?"!

Kijanki,

Do you know who makes good ferrofluid suspended drivers like the ones in you Hyperions - or better yet, the ones found on your speakers? I'd like to learn more for a DIY project.

----

FWIW, back in the "slopped baffle" thread Roy Johnson from Green Mountain Audio made several points about driver size and selection. He mentioned he used a 4.5" midrange driver for his Calypso as it was designed to work in living rooms and audio rooms, but he used larger drivers when designing speakers for vary large rooms. So I wonder how much of a concern is beaming for him, as it would seem the detrimental effect of beaming would be more notorious the larger the room.

Good thread!

As well as bombaywalla tried to explain it, I think dweller is still confused.

Shakey