Wolf,
A Morel Supreme SCW 636 6" Woofer? That would take me over the budget.
I'm in the $400 - $500 range for 4 drivers. Although would consider a pair of $200 Revelators, they seem to work nicely in small boxes.
A Morel Supreme SCW 636 6" Woofer? That would take me over the budget.
I'm in the $400 - $500 range for 4 drivers. Although would consider a pair of $200 Revelators, they seem to work nicely in small boxes.
Ken,
Thank you for this explanation.
I did check out a ceramic cone, they look very nice, and noticeably solid, but like glass can they shatter?
Doug
Thank you for this explanation.
I did check out a ceramic cone, they look very nice, and noticeably solid, but like glass can they shatter?
Doug
Having been there -if you can afford them, I'd go for the Revelators. I do like good hard-cone drivers, but the Revelator remains a superb unit, with that remarkably smooth, extended response and still-excellent distortion performance. It was a great driver of the type when it was introduced, and it still is.
Carbon fibre one has a cone resonance going on at 1.7-1.8kHz which doesn't appear in the other versions. I'd avoid it for that reason.
Flatter out to a higher frequency is not always better, since you probably don't want to use any of these drivers past say 2.5kHz-ish anyway. Ideally it would have a perfect rolloff at 2.5kHz, no breakup and you wouldn't need a crossover
Even if you use a crossover to shape each version into a perfect rolloff, what the drivers frequency response does above your crossover frequency still has implications on distortion. Inevitably the motor produces non-linear distortion components when it plays fundamentals below the crossover frequency, and these distortion components can occur at frequencies above the crossover frequency. When these distortion components land on the cone breakup node(s), they get 'amplified' and played louder compared to the same driver with a cone that doesn't breakup [as severely] at that frequency.
The Aluminium or Ceramic looks best to me (as noted by others, the ceramic is just aluminium with a coating, so is functionally identical). This is because the response rolling off at ~3kHz will mean that all distortion products which land on 3kHz (e.g. 3rd order harmonic of 1kHz, 5th order harmonic of 600Hz) are played slightly quieter compared to say the carbon fibre driver which has an almost flat response past 3kHz.
Consequently, distortion will products which land on the >100dB 7.5kHz breakup node will be louder on the aluminium version compared to say the carbon or polypropylene versions which are only ~95dB at that frequency.
When you have a hard/rigid cone material like metal, it pushes the breakup to a higher frequency and the breakup energy is concentrated on a more narrow range of frequencies so the breakup peaks at a higher SPL. The inductance of the voicecoil causes a rolloff of the frequency response while the cone breakup spikes it back up. That's why the aluminium version is down slightly at 3kHz - because it ISN'T breaking up at that frequency, while the carbon fibre version is mildly breaking up, compensating for the rolloff of the voicecoil inductance and returning the response to almost flat.
It's all a tradeoff - i.e. do you want to accept lower low-order distortion at some frequency range for higher high-order distortion at some other frequency range, or vice versa. Another way of looking at would be do you want a driver that has merely good distortion over a wide frequency range (poly, paper cone), or a driver which has excellent distortion over most of that range and mediocre distortion above a certain frequency (metal, hard materials). Personally i'm a fan of the latter as long as I can restrict the drivers use only to the range where distortion is excellent.
Thankfully the SB17 has a wonderful motor design which produces very little non-linear distortion in the first place, so audibly any two SB17s with slightly different breakup behavior should be pretty much indistinguishable with a sane crossover in place.
That said, personally I'd probably go with the paper or poly version as I hate drivers with unprotected metal domed dust caps - if curious little fingers push them in they become creased and look unsightly even if performance is unaffected
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Some tongues say they are better than the Satoris. Complexity is to choose the good one in the long Revelator list. the coated has often being said to be slighty better, but some says they prefer the 15 over the 18 size ....
We have not too much testimonial about the good paper glass fiber mix of the Wavecores also ?! Low efficienty but measure very well... I read nothing about a subjective sounding face to face comparaison...
Carbon fibre one has a cone resonance going on at 1.7-1.8kHz which doesn't appear in the other versions. I'd avoid it for that reason.
Flatter out to a higher frequency is not always better, since you probably don't want to use any of these drivers past say 2.5kHz-ish anyway. Ideally it would have a perfect rolloff at 2.5kHz, no breakup and you wouldn't need a crossover
Even if you use a crossover to shape each version into a perfect rolloff, what the drivers frequency response does above your crossover frequency still has implications on distortion. Inevitably fundamentals below the crossover frequency produce distortion components above the crossover frequency and these can land on the cone breakup node(s) which 'amplifies' them and makes them louder compared to the same driver with a cone that doesn't breakup [as severely] at that frequency.
The Aluminium or Ceramic looks best to me (as noted by others, the ceramic is just aluminium with a coating, so is functionally identical). This is because the response rolling off at ~3kHz will mean that all distortion products which land on 3kHz (e.g. 3rd order harmonic of 1kHz, 5th order harmonic of 600Hz) are played slightly quieter compared to say the carbon fibre driver which has an almost flat response past 3kHz.
Consequently, distortion will products which land on the >100dB 7.5kHz breakup node will be louder on the aluminium version compared to say the polypropylene version which is only ~95dB at that frequency.
It's all therefore a tradeoff - i.e. do you want to accept lower low-order distortion at some frequency range for higher high-order distortion at some other frequency range, or vice versa. Thankfully the SB17 has a wonderful motor design which produces very little non-linear distortion in the first place, so audibly two SB17s with slightly different breakup behavior should be pretty much indistinguishable with a sane crossover in place.
That said, personally I'd probably go with the paper or poly version as I hate drivers with unprotected metal dust caps/domes - if curious little fingers push them in they become creased and look unsightly even if performance is unaffected
latex water based coating on aluminium has bee tried to smooth that a little ?
We have encountered severe corrosion at the tinsel lead glue joint with the Revelators.
One of my friends and a fellow forum member has had to replace multiple 18W woofers, and even after assurances directly from Scan that the problem was fixed it was in fact, not.
While local repairs do work, they don't look as clean as the factory unit.
Both of use prefer the Scans sonically to the equivalent SB Satori drivers, but the latter are capable of handling some serious abuse and the hot, humid conditions of the tropics (maybe because they're built in this part of the world).
Applying a damping material to aluminium will just spread the energy over a wider frequency range like a poly cone - if that's your goal why not just buy a poly cone? Adding mass will also hurt your sensitivity and typically metal cones are the heaviest to begin with so adding more weight is probably not something you want to be doing.
You're best off not being scared of all the breakup energy being concentrated over a narrow band of frequencies and use it to your advantage. Keep the breakup as high as possible and out of the 1-5kHz region where most of your midrange distortion is going to land. If you restrict the usage of the driver to a frequency range where the breakup node isn't excited (by anything be it fundamentals in the crossover pass band or distortion products produced by the driver's motor) , then there is no disadvantage of the breakup node existing. The same is true of tweeters with a huge ultrasonic breakup node - it can't be heard so there are no ill effects of it existing.
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I personnaly bought a SB23 NBAC, but H5 problems beginn as low as 1300 hz (around 50 db from the fundamental...) so ask earlier cut-off or stiff slope.
It's not a midrange though, more a subwoofer and less smooth than a Dayton RS225.
I find the poly cones not that bad, but find aluminium giving me more. I don't tested at home rohacels sandwich cone yet whatever the surounding material (paper, aluminium, poly, ...)
@ Sangram, Yes India can be extremly hot and wet, can remember a jully in Dehli and Rajhastan... mama mia, better when you're young than old ! viva Imachal Pradesh then ! But all those baba-cools dudes, uh !
It's not a midrange though, more a subwoofer and less smooth than a Dayton RS225.
I find the poly cones not that bad, but find aluminium giving me more. I don't tested at home rohacels sandwich cone yet whatever the surounding material (paper, aluminium, poly, ...)
@ Sangram, Yes India can be extremly hot and wet, can remember a jully in Dehli and Rajhastan... mama mia, better when you're young than old ! viva Imachal Pradesh then ! But all those baba-cools dudes, uh !
Wasn't implying that, Doug. Just in reference to the Rohacell SB units, and my opinions of both. The Glass Fiber Peerless HDS 830991 are a close second place in clarity, and sound good too. I usually like the woven glass fiber or carbon fiber coned drivers.
The Revelator has a following for a reason. I've used them too, and loved them as well.
Another mid of success is the Aurum Cantus AC130F1.
Aerogels from Audax also should be in this list.
If you want the true Accuton ceramic matrix, then the fragility comes into play. They are better as mids than woofers for this reason. Myself, I'd go for the SB ceramics as they sound great!
Wolf
Try again!
That dome mid is not the Dayton bitter-critter RS52 (I don't like them!). That is a set of Usher 9845 2" domes. They are NLA, and oh so wonderful! I bought them 2 weeks before they went disco in July back in 2008. I have acquired more for maybe a center channel, but seems I never get to building me a good one.Yes, the tweeter is the HiVi RT1C-a. Woofers are RSS210HF-4.
This 1ft^3 pair can dredge the depths and make dogs bark, and do it with finesse.
Wolf
As an aside, check out the 1khz HD on the black SB aluminum dome. The ceramic aluminum version I'm sure is no different in that department since they are pretty much identical in every other way. With a steep slope, you could take it WAY low.
SB Acoustics SB26ADC-C000-4 | HiFiCompass
SB Acoustics SB26ADC-C000-4 | HiFiCompass
SB26ADC
a sort of a little too much high H5 around 1100 hz, just checked the link.
a 2200 Hz cut-off LR12 could do the trick good enough perhaps... but I never saw that little bump around 6000 hz on the power response, does it transcript into a brightness than should be tamed ? Maybe not on the CAC version ?!
@ Wolf_teeth : i wanted to buy this dome I call the Proac dome for poors but ten years after you when I get the information about its good sound... The metal version of the Dayton is used by the fun guys of HTGuide, but I heard neither of both...
a sort of a little too much high H5 around 1100 hz, just checked the link.
a 2200 Hz cut-off LR12 could do the trick good enough perhaps... but I never saw that little bump around 6000 hz on the power response, does it transcript into a brightness than should be tamed ? Maybe not on the CAC version ?!
@ Wolf_teeth : i wanted to buy this dome I call the Proac dome for poors but ten years after you when I get the information about its good sound... The metal version of the Dayton is used by the fun guys of HTGuide, but I heard neither of both...
Hi, Doug,
First, a disclaimer. I'm an electrical, not a materials engineer, so what follows is hardly authoritative.
That said - the propensity of a high-Q material to shatter, not surprisingly, depends on the material (plus it's manufacture and construction). For example, glass is relatively brittle, and easily shattered, while most metals are not easily shattered even though both materials are high-Q. Glass is a more rigid material than some metals - which typically are malleable (deform but don't shatter) when stressed. The exact kind of deformation is important. Rock-like materials are famously strong under uniform compression, but relatively weak or brittle under tension, or torsion, or especially under transverse stress. Ever wonder how Karate masters can break bricks with their bare hands? That's how. As for ceramic cone materials, I suspect they benefit from a reinforcing material. Just like poured concrete greatly benefits from the inclusion of steel rebar. As far as ceramic cone reliability is concerned, if there were in-use reliability problems, I think that it's safe to say we would have widely heard about it by now.
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The SB Acoustic drivers, as mentioned a few times in the thread, are not really ceramic but heavily oxidised aluminum and have the same properties as the underlying diaphragm.
The Thiel/Accuton drivers are fully protected from the front with a grill that prevents any poking, because that is a cast ceramic cone. It is very brittle to touch, and has some mechanical limits that need to be heeded.
Faq
In the second paragraph.
The Thiel/Accuton drivers are fully protected from the front with a grill that prevents any poking, because that is a cast ceramic cone. It is very brittle to touch, and has some mechanical limits that need to be heeded.
Faq
In the second paragraph.
Interesting. Living in the UK, I can't say I've ever had this issue myself, but certainly for those in a more humid environment it would be worth keeping in mind.
As has been noted, the SB ceramic series units are aluminium with the surfaces deep-oxidised; it's not pure ceramic, nor an applied coating, so it won't crack or shatter. The tweeters are very good for the money, and the 5in midbass units, especially the 4ohm models, are rather good examples of the type.