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Purifi PTT6.5W04-01A 6.5" midwoofer

Lbstyling

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I'm not so sure about that. One of the most important speaker parameters is dispersion characteristics. If you want to have even dispersion with frequency, there is no beating a smaller midrange crossed over to a (smaller) tweeter, which necessitates a three-way design. Unless you want to put the drivers inside a waveguide, but that brings new complications to the table. This driver starts struggling off-axis already at 1500 hz. It's good compared to many other drivers of the same size, of course, but it's not good - when it comes to off-axis response in the midrange - compared to many 3- or 4-inch drivers.

If one wants to keep the speaker small, though, it would have been exciting to see an active DSP based 3-way with this as the woofer, crossed over to a 2- or 3-inch driver around 1000 hz, crossed over to a really small wide-dispersion tweeter around 6 or 7 khz. Something like that (this is just a guess as to what would work out). Now we're suddenly talking about a speaker which has deep bass, is slim and small, has no crossovers in the most sensitive region, and probably could achieve very wide and even dispersion over the whole frequency range (way beyond what a 2-way could achieve in terms of dispersion). Pretty neat!
(ping @March Audio - I have no idea whether this would work out or not, but given that you're already making an active speaker with this as the woofer...)
It works!

I’m very late to this thread, but I was nodding in agreement about the driver sizes and crossover points to control dispersion.

Then I realized these are the exact crossover regions in the top baffle used by Linkwitz in his final LX521 design.

He chose the sizes, baffle widths and crossover points for the same reason—to keep dispersion wide and smooth across the frequency range. He crosses over the 8” and 4” at 1000hz, and the 4” and 1” tweeter at 7khz (and at bottom 120hz to dual seas 10”)

It seems like the Purify woofers could be used in place of the 8” to take the top part even slimmer.

I’m currently contemplating a 2 way dipole to be used as height speakers directly above my Linkwitz Orion dipoles

To keep it small, I could use these Purify mids, but cross over to a tweeter such as the new Bleisma’s at a lower crossover point down to 2khz if possible where the Purify dispersion is still wide. Bass would be crossed over to the home theater dual 12” subs.

http://www.linkwitzlab.com/LX521/Description.htm
 

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Matias

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AnalogSteph

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Cool. Funny how at 105 dB the Purifi has less distortion than the 12" PA midwoofer (which, mind you, is likely to be optimized for high efficiency @ 101.5 dB nominal and only costs about half as much either, but does enjoy the advantage of almost 4 times as much Sd).

I only noticed now that his distorton products are plotted on a different scale from the fundamental. So his limit is at about 0.01% = -80 dBr, or noise floor as low as 15 dB SPL.
 
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