If you were building a 2 way with a Scanspeak ring radiator on a waveguide crossed @ 1.5khz, what would woofer would you use? Revelator 18W/8531G-00 or one of the Classic series like 18W/8542-10 or 18W/8545K?
If having to choose between those 3 it would have to be the Revelator - it's slightly more efficient and has a more linear response that should result in a less complicated filter to obtain an equal level of linearity.
I discount the 18W/8542-10, its not in the same class as the others.
I discount the 18W/8542-10, its not in the same class as the others.
Whats wrong with the 8542 Scott? Looks more linear than the 8545k in the frequency response and had similarly low distortion.
Of course the Revelator beats them both.
Of course the Revelator beats them both.
Revelator gets my vote. Very linear, easy to make crossover, LR2 possible, and will sound good with RR in WG.
Virtually identical in linearity from what I've seen
http://www.zaphaudio.com/6.5test/18W8531G-HD.gif (note -10dB fundamental level)
https://www.feleppa.com.au/pics/speaker_imgs/plots/SS18W8545_RawHarm.png (note raised 2nd order HD from microphone - my microphone is not as good as Zaphs)
8531G's freq response >1kHz is perhaps a bit easier to work with in a 2-way.
I think the 8545 looks aesthetically better and lacks a dustcap that is easily poked in, but I'm also biased because I own them.
8542 is basically the same thing as 8545 with a slightly tweaked frequency response due to dust cap and surround. I would avoid because foam surrounds don't last as long and there is nothing wrong with the rubber surround on the 8545.
http://www.zaphaudio.com/6.5test/18W8531G-HD.gif (note -10dB fundamental level)
https://www.feleppa.com.au/pics/speaker_imgs/plots/SS18W8545_RawHarm.png (note raised 2nd order HD from microphone - my microphone is not as good as Zaphs)
8531G's freq response >1kHz is perhaps a bit easier to work with in a 2-way.
I think the 8545 looks aesthetically better and lacks a dustcap that is easily poked in, but I'm also biased because I own them.
8542 is basically the same thing as 8545 with a slightly tweaked frequency response due to dust cap and surround. I would avoid because foam surrounds don't last as long and there is nothing wrong with the rubber surround on the 8545.
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I would go for the revelator. I hear some harshness with the 8545 that can be annoying, especially so from electric guitars
But 8545 (and 8535 ) has the advantage that the high freq roll off is very similar on and off axis which i find to be quite unique
But 8545 (and 8535 ) has the advantage that the high freq roll off is very similar on and off axis which i find to be quite unique
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..the 8542 is actually a bit more linear than the 8545k, which is good. But I don't like the way 5th order distortion looks on the 8542, nor do I like the higher harmonic results with power scaling as excursion increases when compared to the other 2. (..though interestingly the 8545k scales better with respect to 2nd and 3rd than the Reveleator.)
I'm also not fond of fibrous damping (stiffening yes, damping no), and like wool (as with the Silver Flute drivers) - that's what the nylon fill is there for in the 8542. It's not really a problem as you go lower in freq.. but much past (higher than) 600 Hz or so it tends to reduce low-level detail. As for the foam surround - sometimes they are better subjectively and objectively, and if they are coated properly should last a long time. (..subjectively you can *sometimes improve low-level detail; objectively you can often improve the anti-phase and therefore poorer linear result from that of a typical rubber surround, plus most foam surrounds weigh less and typically result in a more efficient driver.)
*depends on how compliant the surround is.
I've had 3 x 18W8545K in parallel for mid-woofer duty between 80 and 500hz. Works great. But I would never use any 18W as a midrange. Simply to much breakup(distortion/coloration) - for me.
When you use a wave guided tweeter and crossing low - like you do, then maybe it would work. Heissmann seems to make it work, even with the 22W 4534G00:
Heissmann Acoustics | Disco-M | 20l reference speaker
When you use a wave guided tweeter and crossing low - like you do, then maybe it would work. Heissmann seems to make it work, even with the 22W 4534G00:
Heissmann Acoustics | Disco-M | 20l reference speaker
Of the 6” drivers on hand, I have currently have Purifi PTT6.5, SS 8545 and W18E-001 and B&W 6” FST…
If you can take care of that broad 1 octave bump ~800Hz, from 100Hz to 2.5Khz, the 8545 may be old, but is not outdated…
If you can take care of that broad 1 octave bump ~800Hz, from 100Hz to 2.5Khz, the 8545 may be old, but is not outdated…
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The uneven frequency response in the 8545, between 500-2kHz, is a killer for me. I really wouldn't bother unless I had no choice. I do like the way it looks though.
I really don't like the way the 8542 looks, even if, objectively, it seems like a better driver for a 2 way.
The revelator, on the other hand? Not bothered about its looks but its frequency response is smooth and extended and the distortion is low. Well apart from the peaking 2nd order that most soft cones tend to exhibit throughout the midrange.
I really don't like the way the 8542 looks, even if, objectively, it seems like a better driver for a 2 way.
The revelator, on the other hand? Not bothered about its looks but its frequency response is smooth and extended and the distortion is low. Well apart from the peaking 2nd order that most soft cones tend to exhibit throughout the midrange.
Fwiw, I have a pair of (albeit used/old) 8545k’s here, and I didn’t even bother boxing them up to measure because the ts specs were so far off the data sheet from the first DATs sweep I did.
They will be sold, and cheap.
They will be sold, and cheap.
Yes this has been identified in Scan-Speak drivers quite often in the past. This is a known issue for long time, to the point that SS get they needed to address it:
https://www.scan-speak.dk/datasheet/tech/Scan-Speak_Technote01_TS-measurement.pdf
But with your own measured T/S parameters; if you punch it into your box modeller, it doesn’t really change the alignment that much from Scan-Speak’s.
Yes you can sell me the 8545K cheap. If anyone else has the 15W/8530K and don’t like the 800Hz bump and would like to sell it for cheap; please PM me.
https://www.scan-speak.dk/datasheet/tech/Scan-Speak_Technote01_TS-measurement.pdf
But with your own measured T/S parameters; if you punch it into your box modeller, it doesn’t really change the alignment that much from Scan-Speak’s.
Yes you can sell me the 8545K cheap. If anyone else has the 15W/8530K and don’t like the 800Hz bump and would like to sell it for cheap; please PM me.
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How did you go? Did you end up getting the driver and doing a design with it?
John Krevskovsky's NaO 2 is one of my favourite speakers and he knocked it out of the of the park with that design. He uses a fancy active-passive hybrid crossover, or full active crossover, totally flattening out that broad 1 octave hump between 500Hz and 1KHz.
It really makes the 18W8545 sing...
John Krevskovsky's NaO 2 is one of my favourite speakers and he knocked it out of the of the park with that design. He uses a fancy active-passive hybrid crossover, or full active crossover, totally flattening out that broad 1 octave hump between 500Hz and 1KHz.
It really makes the 18W8545 sing...
This project won't happen until next year. I have two huge projects for this year that will suck up all my free time.