Just for grins I threw the 15M/4624G specs into WinISD. Using a closed box WinISD suggested a 2.2 L size for a Qtc of 0.699. I then set the signal to max spec, 75W. This gave an output of 110 dB. With a second order Butterwoth highpass at 350 Hz the max excursion is just under 1 mm at about 250 Hz. Changing the filter to a 4th order LR (still at 350 Hz) gives a max excursion of 0.6 mm at about 350 Hz. I would agree 110 dB is a stupid soundpressure level!
Anyone who listens to music at constant 110 SPL is stupid and risk damage his/her ear drum permanently. We all agree that no one does that.
Music is dynamic. The average listening level in a typical domestic room may be about 65-75 SPL. But there are peaks of a few to a few tens of mini seconds (ms) that can reach 110dB SPL. That's what we mean by "ability to play loud without distortion". The dynamic headroom may be more important to some listener than to others. There is no need to argue about that.
350 Hz is a low frequency for crossing over to a midrange driver. The Scanspeak 15M/4624G is a midrange driver so your argument is perfectly valid.
But 350 Hz is somewhat high for a midwoofer as Absconditus originally wants. 250 Hz or below is more typical for a midwoofer. I look for 3.5 mm Xmax driver for crossover at 250 Hz or higher. 5 mm Xmax or longer for 120 Hz or lower. This are not exact science, just gut feel from listening.
I will like to switch back from "midrange" to "midwoofer" discussion. I will like the 2-way closed box to have low distortion down to 100Hz to allow me to experiment with crossover between 100-250 Hz using active LR4.John "Zaph" Krutke said:
In older designs, the Scanspeak Revelator 5.5" such as the ScanSpeak 15W/8530K-01 was used with very good results. But at $400 a pair, it is a little too rich for me.
Another midwoofer, SB Acoustics SB15NBAC30-8 5" Aluminum Cone Mid-bass seems to be a good candidate without the ragged upper range of the Aurum Cantus AC130/50CK. It also have a ceramic cone version. Any first hand comment on this SB Acoustics driver is appreciated.
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Remember that the near-field 20mm HD testing is for freq.s below about 200 Hz, and the 315mm for everything above it:
SB Acoustics SB15NBAC30-4 | HiFiCompass
I doubt the CAC are really much different..
SB Acoustics SB15NBAC30-4 | HiFiCompass
I doubt the CAC are really much different..
Scott, thank you for coming through for me again. The SB Acoustics BAC aluminum cone 5" seems to have all I am looking for, and a distortion as low as the Scanspeak Revelator drive. If I get no negative feedback about this choice, I will put in an order the next few days.
I also save $60+ vs. the Aurum Cantus too. A nice bonus.
Thank HiFiCompass! 
Some speaker driver measurements...
-can't see why anyone wouldn't like the SB driver (it's objectivly excellent) ..other than the fact it's grossly in-efficient. (..but then again, just about every wide-bandwidth 5" is - and those with only decent spec.s at that.)
Gornir has also measured them:
www.audioexcite.com >> Blog Archive >> SB17NBAC35-4 vs SB17NAC35-4
Some speaker driver measurements...
-can't see why anyone wouldn't like the SB driver (it's objectivly excellent) ..other than the fact it's grossly in-efficient. (..but then again, just about every wide-bandwidth 5" is - and those with only decent spec.s at that.)
Gornir has also measured them:
www.audioexcite.com >> Blog Archive >> SB17NBAC35-4 vs SB17NAC35-4
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For a midrange, efficiency is not so critical, because there is no need for baffle step compensation.
The thing I hate with 5" woofers is the deep cone thick surround roll needed for high excursion. It deteriorates upper end off-axis response smoothness very often, seen as response wiggles between 2-4khz. Heavy moving mass might be a caveat too.
Satori MW16P is in same league in performance and price with this Fostex, that looks like a very good midrange driver!
Fostex FX120 | HiFiCompass
The thing I hate with 5" woofers is the deep cone thick surround roll needed for high excursion. It deteriorates upper end off-axis response smoothness very often, seen as response wiggles between 2-4khz. Heavy moving mass might be a caveat too.
Satori MW16P is in same league in performance and price with this Fostex, that looks like a very good midrange driver!
Fostex FX120 | HiFiCompass
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^Yes!
Please remember that Fostex has 5dB higher sensitivity, and distortion was measured at certain voltage, not dB level. But yes, Satori has better motor.
The most striking difference is off-axis response behaviour from 2kHz up, for the benefit of Fostex. A midrange is often asked to be crossed at 300/3000Hz, even 4-5kHz and shallow slope LR2. Satori has rapidly rising directivity right above 2kHz because of it's deep cone and thick surround roll, which will make troubles in off-axis response - unless crossed LR4 around 2kHz like any modern 2-way speaker.
I haven't heard either, this is just speculation, but I would choose Fostex for a 3-way!
Please remember that Fostex has 5dB higher sensitivity, and distortion was measured at certain voltage, not dB level. But yes, Satori has better motor.
The most striking difference is off-axis response behaviour from 2kHz up, for the benefit of Fostex. A midrange is often asked to be crossed at 300/3000Hz, even 4-5kHz and shallow slope LR2. Satori has rapidly rising directivity right above 2kHz because of it's deep cone and thick surround roll, which will make troubles in off-axis response - unless crossed LR4 around 2kHz like any modern 2-way speaker.
I haven't heard either, this is just speculation, but I would choose Fostex for a 3-way!
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I built a 2-way with the SB15NAC30-8 (basically the same as the SB15NBAC30 with a different cone color) and it sounds excellent. Very clear. The only complaint I had is that with high complexity music with decent bass content (some metal, orchestral scores) it can sometimes get a little hard to pick different instruments apart, but I believe that is because I am using it from 2.4kHz all the way down (f3 is 38 Hz), which will result in higher intermodulated distortion. It also doesn't have the greatest max SPL, but that's because I'm using it so low
As a dedicated midrange, it would be exceptional as long as you don't cross it over too high.
As a dedicated midrange, it would be exceptional as long as you don't cross it over too high.
I wouldn't use either, but then I wouldn't do a traditional 3-way either.
It's just a LOT better for a variety of reasons to use more appropriate driverS within their respective pass-bandsS. Of course one of which is upper freq. off-axis.
4-way MINIMUM, and likely a 5-way with subwooferS.
People tend to "shy-away" from this because of perceived filter complexity and cost, but the fact is that you can generate a LESS complex filter (both in slope-character and component-quantity) - and IF you spend even on moderately priced crossover components: the price difference will usually MORE than offset the cost of the additional drivers. The net result is a lower parts cost.
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But the Satori MW16P has rising HD2 below about 600 Hz. It is not in the league as the other midwoofers I am considering in term of distortion. So the Satori MW16P is good choice for a midrange in system using low order crossover. It does not meet my need for low distortion in the mid bass.Troels Gravesen said:
The upper midrange cone breakup is in most midwoofers and not difficult to remedy.
Besides, Satori costs twice as much as the SB Acoustics 5" AL cone.
Thank you for sharing your experience. I will be very interested in seeing some pictures and the crossover schematic of your system.I built a 2-way with the SB15NAC30-8 (basically the same as the SB15NBAC30 with a different cone color) and it sounds excellent. Very clear. The only complaint I had is that with high complexity music with decent bass content (some metal, orchestral scores) it can sometimes get a little hard to pick different instruments apart, but I believe that is because I am using it from 2.4kHz all the way down (f3 is 38 Hz), which will result in higher intermodulated distortion. It also doesn't have the greatest max SPL, but that's because I'm using it so low
As a dedicated midrange, it would be exceptional as long as you don't cross it over too high.
Thank you for sharing the pictures. They look beautiful. Can you share why you recess the tweeter, but not the woofer?
In this case, it just so happened that flush mounting the tweeter but not the woofer resulted in getting the two drivers pretty close to being time aligned. Also, from what I've read (someone correct me if I'm wrong please ) it's more important to flush mount the tweeter than the woofer from a diffraction perspective.
) it's more important to flush mount the tweeter than the woofer from a diffraction perspective.- Status
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