I’m narrowing down my driver choices for my MT design project. The leading candidates are the ScanSpeak 6600 tweeter (4 ohms, 92.5 db) and the ScanSpeak 18W(X)531 Revelator 6.5” woofers. These woofers come in various versions. There are:
A 4 ohm, 90 db sensative variant:
An 8 ohm, 87 db flavor:
A 16 ohm, 83 db version:
And a shielded 8 ohm, 86.5 db one:
In general, do you just pick the driver that has the highest sensitivity? I realize how that helps in needing less amp power to achieve a given SPL. That would be the 4 ohm/90 db one here.
I’m guessing the 16 ohm sensitivity (83 db) is way too low. And for the shielded 8 ohm driver, you loose 0.5 db relative to the non-shielded version, so no reason to get that. I’m left with the 4 ohm/90 db and the 8 ohm/87 db. From my reading, high sensitivity is a good thing. So just use the 4 ohm/90 db choice.
I’m also figuring that the frequency output, impedance, and distortion characteristics of these drivers are all pretty similar. They look to be from the ScanSpeak plots. Zaph and MarkK tested different versions (one did the 8531, the other did 4531) and both looked excellent, hence my likely choice of these drivers. (Except for the unfortunate impedance warble at ~1000 Hz)
Looking back at the Modula MT, MTM, etc. projects it seems that Jon picked the 8 ohm/87.6 db flavor of the RS180 over the 4 ohm/91 db version. So maybe I’m not thinking about it correctly. Or perhaps I recall that only the 8 ohm version of the RS180 was available when he did his designs.
Thanks.
-Jon
A 4 ohm, 90 db sensative variant:
An 8 ohm, 87 db flavor:
A 16 ohm, 83 db version:
And a shielded 8 ohm, 86.5 db one:
In general, do you just pick the driver that has the highest sensitivity? I realize how that helps in needing less amp power to achieve a given SPL. That would be the 4 ohm/90 db one here.
I’m guessing the 16 ohm sensitivity (83 db) is way too low. And for the shielded 8 ohm driver, you loose 0.5 db relative to the non-shielded version, so no reason to get that. I’m left with the 4 ohm/90 db and the 8 ohm/87 db. From my reading, high sensitivity is a good thing. So just use the 4 ohm/90 db choice.
I’m also figuring that the frequency output, impedance, and distortion characteristics of these drivers are all pretty similar. They look to be from the ScanSpeak plots. Zaph and MarkK tested different versions (one did the 8531, the other did 4531) and both looked excellent, hence my likely choice of these drivers. (Except for the unfortunate impedance warble at ~1000 Hz)
Looking back at the Modula MT, MTM, etc. projects it seems that Jon picked the 8 ohm/87.6 db flavor of the RS180 over the 4 ohm/91 db version. So maybe I’m not thinking about it correctly. Or perhaps I recall that only the 8 ohm version of the RS180 was available when he did his designs.
Thanks.
-Jon
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