I already built mine! 😎
(plan to reuse the 20L PR cabinets I built originally for the PTT6.5 It can be trimmed down accordingly 😉)
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You’ll be fine if you have a cabinet with a cutout for a Scan-Speak classic 21W, or an old Revelator 22W
yes.
Perhaps that’s why they are re-branded the Classic line.
they certainly are vintage products, but still good performers!
oh yes please! A 5.25“ midrange would be fantastic!!
However the frequency response of the X version as shown on the Purifi website already looks extremly good.
So what would a dedicated midrange do better, except the presumably higher sensitivity?
Is there any prediction possible, when both will be available?
Best regards
Matthias
good question. mostly looking for higher sensitivity and perhaps a tad more BW. also a narrower surround will reduce the shelve down from about 800Hz where the wide surrounds decouples from the motion. dispersion will be a tad worse with a more narrow surround ( the cone grows)
It seems that most good designs are using a waveguide anyway to control dispersion, smooth transition, create a possibility for a lower cross over frequency and lower distortion. So how problematic is dispersion from a 5" in practical terms ?
Looks impressive. Do you have a sneak peak of the impedance plot also? Doing some simulations with different tweeters. Just using the impedance plot of a 6.5" purifi driver for the sims. Of course not correct but somewhere in the ballpark I assume. Interesting simulations BTW.
A waveguide mostly narrows directivity and increases the center to center distance of the drivers. Being able to cross higher to the tweeter means lower distortion from the tweeter. a WG will also lower harmonic distortion thanks to the on axis gain so that drive level can be reduced. No free lunches here - all compromises. of course the width of the 5” surround impact on dispersion is marginal
Thanks for the reply, Lars.
As I am looking for a midrange in an open baffle system (with a very narrow or even no baffle for the midrange driver) the mentioned difference seem to be quite subtle for this use case, and should be able to be partly compensated in an active system with dsp.
The shelve at 800Hz from the X version in this use case could even be a positive thing as it might partly compensate the dipole raise, with a dipole peak somewhere between 1kHz and 2kHz.
I was also looking at the 6.5inch midrange driver, but I'm afraid that it will be a bit to big to keep constant directivity, if the XO to the tweeter will be somewhere at 2.3kHz
BR
Matthias
Yes... I see the waveguide as a very good thing, since the CTC does not have to be larger if the waveguide is elliptical. You also fix the acoustical center by moving the tweeter dome back, and I actually find that the stereo image improves drastically with a slightly narrow directivity, since a top/front mounted tweeter spread the sound way more than a midrange, creating a very abrupt change in directivity - again creating this distinct difference between tweeter and midrange, rather than a coherent sound throughout this critical frequency band.
So my point is. The midrange will start to beam somewhere - that's the law 😉... but as long as it does it controlled and smoothly - also off-axis - then it should be easy to integrate it with most well suited tweeters.