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In the Forum: Audio Discussions
In the Thread: The loudspeakers for a powerful SET
Post Subject: Test BedPosted by Paul S on: 4/12/2008
Being both fairly lazy and fairly cheap with respect to audio, I remain very interested in the
FR SET/dynamic speaker dream.  Also, I am generally both weary and wary of the extreme complexity/difficulty engendered/entailed by other FR approaches.

When I first started the DEBZ project, I admit I was not sure if they (at 97 dB) could be driven FR with garden variety SETs, especially considering the 15" woofer.  As it turned out, there were some problems I anticipated and some that emerged as the stark contrast between what the DEBZ/Wright 2A3 SETs did right versus what they did wrong or just could not do. I have written of these things in other posts.

The bar was certainly raised with the ML2s, and they also introduced some amazing experiencess that I never saw coming.  BUT: some of the old issues remain, such as ultimate dynamics and, of course, true LF, and not all of the issues are due to the speakers, per se.  Sure, there's lots more with the ML2s than with other SETs I've tried; but there's nothing like orchestral music to put things back into proper perspective...

Anyway, I agree that rated efficiency should be about as high as reasonably possible if there is to be any hope of FR SET.  However, there is another issue I am thinking about with rated-high-efficiency speakers that also have very high "allowable power" input ratings.  Namely, most of these speakers just eat up amplifier power at an alarming rate, much faster than the 3 dB/double power rule suggests, and this sort of speaker IMO invariably winds up needing big amplifiers to deliver its best.  This means that driver choice is critically important for use with SETs, not to mention crossover logistics.  I know that atomic scientist Dick Olsher used a LEAP program and then his own ears to work out the DEBZs, and I think this sort of "objective" modeling is a worthwhile preliminary step.  But in the real world, and as we hear it, crossovers are a sombitch to design and implement, and they invariably act a lot weirder than any model would suggest, including acting as non-linear "sinks", not to mention the reactive elements.

I am thinking that even in the case of a 4-way system I like the idea of a wide range driver in the mix, if only to circumvent crossovers and driver matching.  I have thought for a while that the biggest problem with the DEBZ is the usual loudspeaker Achilles heel, namely weight (setting aside for the moment ultimate dynamics).  Based on previous experience, I still imagine that a 10" driver just does better in the lower mids, other factors being equal.  Now, if I could just find a 10" "wide range" driver half as fast as the Lowther...

If anyone has tried the ML3 it would be interesting to hear what with and how its power unspooled.  I think this will be the crux of any FR SET/speaker project.

If we assume that the ML3 is a more powerful ML2, then it MIGHT open the door for a 4-way system, and MAYBE even 5-way, although it is still hard for me to imagine 4-way and bass from 1 SET.

Best regards,
Paul S

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