On my forum, I keep a list of which sub drivers offer the most bang for the buck. We have a new champion this week, from Canada. It displaced the Tempest as the biggest 'bang for the buck' sub driver.
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Audio Psychosis • View topic - The Bass Race
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Audio Psychosis • View topic - The Bass Race
Hi Patric,
Good to know and if put in use: The Tempest driver promise good performance too:
b
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I love these kinds of lists. But it should be mentioned that because of the different standards that different manufacturers use to rate xmax, the results are a bit misleading.
For example, I think Eminence rates xmax at the 10 percent distortion point.
Exodus, I believe rates xmax at 30 percent distortion.
I have no idea how Mach5 does it, but I'd be willing to bet it's not 10 percent. Same with TC Sounds woofers, CSS woofers, and all the super high rated xmax woofers.
So it should be kept in mind (and perhaps noted in the Bass Race thread) that without Klippel data you very well might be (probably are) comparing apples to oranges in terms of xmax, and by extension, displacement.
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Feel free to donate money/drivers (this goes for everyone, not just you) to bikinpunk at DIYMA. He's got the Klippel rig set up for T-S and raw motor/suspension curves, and will soon be getting HD/IMD capabilities too.
I'm aware of him and his work, he's in a few different forums under different names. I'm not sure if he's interested in sub drivers, he's been testing lots of mids/midwoofers. Either way, I can't even afford these drivers, let alone paying the (international) shipping back and forth to bikinpunk.
I don't think a Klippel test on every single interesting woofer is really necessary anyway, although it would be really nice. The most important thing is to realize that there are differences in how xmax is determined, and as Saturnus pointed out it would be nice to see Xlim for each driver in the Bass Race list.
And one more note before I let this go.
I realize that this list is ONLY concerned with displacement, but more displacement doesn't always = more bass. At least a cursory glance should be given to the driver specs to determine how it is likely to be used. Sure, the Alpha15 has decent displacement/$$$ but it's almost completely useless in anything besides OB, and on OB it really won't have much bass at all. You could get more bass out of a regular 10 inch driver (and certainly a whole lot more from a low priced Beta15) in a ported box.
Anyway, I don't mean to be nitpicky, I still like lists like this but there are so many other things to consider than manufacturer rated displacement.
I realize that this list is ONLY concerned with displacement, but more displacement doesn't always = more bass. At least a cursory glance should be given to the driver specs to determine how it is likely to be used. Sure, the Alpha15 has decent displacement/$$$ but it's almost completely useless in anything besides OB, and on OB it really won't have much bass at all. You could get more bass out of a regular 10 inch driver (and certainly a whole lot more from a low priced Beta15) in a ported box.
Anyway, I don't mean to be nitpicky, I still like lists like this but there are so many other things to consider than manufacturer rated displacement.
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Displacement per watt would also be nice if you're really going to do a list.
A quick and dirty calculation of 2 of the drivers given (the Eminence and the TC sounds) shows that the Eminence can displace 2.5 times as much air per watt (10 times better efficiency but at roughly half the Fs) , and although limited to 200Wrms that correlates precise by 2.5 times to the 500Wrms of the TC sounds, so in effect both drivers can displace precisely the same amount of air in total within their specified power handling.
A quick and dirty calculation of 2 of the drivers given (the Eminence and the TC sounds) shows that the Eminence can displace 2.5 times as much air per watt (10 times better efficiency but at roughly half the Fs) , and although limited to 200Wrms that correlates precise by 2.5 times to the 500Wrms of the TC sounds, so in effect both drivers can displace precisely the same amount of air in total within their specified power handling.
This opens up another can of worms though. Displacement per watt depends almost entirely on the alignment you put the driver in (at subwoofer frequencies at least). You get a whole lot less displacement (but a whole lot more bass) out of a horn compared to OB. Since the Alpha15 is useless outside of OB useage, there's no "standard" alignment that you can rate all the drivers by in terms of displacement per watt.
Yeah, but dont' forget that the raw driver's sensitivity AND power handling spec is also open to interpretation and presented differently by a lot of manufacturers. Even if there was a standard, power handling is also directly related to the alignment. For example, a driver in a big horn can handle way more power than the same driver in a small closed box. I think Danley said the Lab12 driver (rated at 400 watts) should be able to handle close to 2000 watts each (assuming a stack of 8 horns or more in 2pi space.)
So it's not easy to directly compare drivers made by 2 different manufacturers bases solely on their xmax and/or sensitivity and/or power rating.
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The fact is, SPL is dependent on frequency and displacement only. Even if a woofer doesn't want to be a sub, you can still EQ the heck out of it and get your bass back.
Are you sure?
In other words, if you take 2 of any given driver and put 1 in a massive horn and 1 in a small baffle OB, you think they would make the same SPL at xmax at any frequency below 120 hz?
Your statement is only true at higher frequencies, down low the enclosure is everything.
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I'm not sure what I was thinking when I wrote this, but there's multiple errors, sorry.
It was Seaton that said it, I believe, and it was 2000 watts or more per sub, in other words at least 1000 watts per driver (not 2000 per driver) and he was referring specifically to a stack of as little as 4 Labhorns.
Wow, 3 errors and 1 omission in 1 sentence. Not sure where my head is today.
To paraphrase just a guy's statement above I might wonder if Patrick's list has any significance at all.
Given that absolute displacement is the crucial factor, displacement/dollar might perhaps be used as some effeciency measure between speakers displacing (nearly) the same amount of air. But just then.
Comparisons of this kind also rest on an implicit 'ceteris paribus' clause - that is 'all other things equal' which of course is not the case in any of the comparisons here.
/Erling
Given that absolute displacement is the crucial factor, displacement/dollar might perhaps be used as some effeciency measure between speakers displacing (nearly) the same amount of air. But just then.
Comparisons of this kind also rest on an implicit 'ceteris paribus' clause - that is 'all other things equal' which of course is not the case in any of the comparisons here.
/Erling
Hi,
Its quite easy to find much "better" based on that simple criterion, e.g. :
MCM Audio Select 15" Woofer with Poly Cone and Rubber Surround 200W RMS at 8ohm | 55-2974 (552974) | MCM Audio Select
$27 for a 15" with 6mm Xmax works out $53 per litre.
You get what you pay for though ..... but more usable than an Alpha A :
Sensitivity: 92dB (W/M)
Impedance: 8ohm
Re: 7.2ohm
Le: 1.522mH
Frequency response: 50Hz~3KHz
Fs: 32.5Hz
Qts: 0.47
Qes: 0.56
Qms: 3.08
Vas: 322.23 liters
Xmax: 6mm
Overall frame diameter: 15.08"
Required cutout: 13.82"
Mounting depth: 5.63"
rgds, sreten.
Its quite easy to find much "better" based on that simple criterion, e.g. :
MCM Audio Select 15" Woofer with Poly Cone and Rubber Surround 200W RMS at 8ohm | 55-2974 (552974) | MCM Audio Select
$27 for a 15" with 6mm Xmax works out $53 per litre.
You get what you pay for though ..... but more usable than an Alpha A :
Sensitivity: 92dB (W/M)
Impedance: 8ohm
Re: 7.2ohm
Le: 1.522mH
Frequency response: 50Hz~3KHz
Fs: 32.5Hz
Qts: 0.47
Qes: 0.56
Qms: 3.08
Vas: 322.23 liters
Xmax: 6mm
Overall frame diameter: 15.08"
Required cutout: 13.82"
Mounting depth: 5.63"
rgds, sreten.
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The Lab 12 can handle 2000 watt peaks, but will burn up given little more than 400 watts continuous sine wave, whether in a ported, sealed or horn loaded enclosure. I have been demonstrating my ported Lab 12s with just over 1000 watts (peak) per speaker, I have no doubt that 2000 watt peaks per driver could be sustained above Fc in a proper horn cabinet.
Fc will lower in a large array of horns, but that change won’t affect power handling, other than the small change in the impedance curve.
Fs lowers in multiple driver bass reflex cabinets too, for what it is worth.
A horn loaded cabinet may raise average impedance, which can result in less average power than another alignment given the same voltage.
The enclosure is important as far as bass output, but given the same enclosure, a driver with greater Xmax capability simply can put out more peak SPL than one with less.
As has been repeated in the thread, that statement assumes that the Xmax figures are correct.
Having tested lots of different Eminence drivers, I know their figures are correct, I’d pay a bit more per displacement for a driver from a company that has stood the test of time.
Then again, there are drivers like sreten suggests in post #15, $27 for a 15" with 6 mm Xmax, that are probably worth taking a chance on if the goal is mainly moving some air.
Art Welter
I thought that you would see the implicit assumption that I was talking about apples, not apples and oranges. Regardless of the type of enclosure, more displacement means more SPL, period. Yes, one driver in an OB is likely to produce less SPL than a driver in a regular monopolar box, which will produce less than the same driver in an ideal horn... but neither of us are idiots. I hope. Are you sure?
Ok, so you are saying that if you have 2 drivers in the same type of enclosure and the drivers are identical but one has more xmax, that the one with more displacement will win?
Ok, I fully agree, that much is almost too obvious to be stated. But it doesn't have anything to do with the statement you quoted from me. I was trying to point out that the drivers on the list WILL NOT work in the same type of alignments at all so they are in fact apples and oranges. The Alpha will ONLY work well on OB while the other drivers listed work best in other alignments, so rating them based on displacment alone has limited usefulness.
Ok, I fully agree, that much is almost too obvious to be stated. But it doesn't have anything to do with the statement you quoted from me. I was trying to point out that the drivers on the list WILL NOT work in the same type of alignments at all so they are in fact apples and oranges. The Alpha will ONLY work well on OB while the other drivers listed work best in other alignments, so rating them based on displacment alone has limited usefulness.
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Actually the change in the impedance curve looks pretty dramatic when you compare 1 cab vs 8. I have no experience with the driver itself and certainly no experience with stacks of horn subs so I don't know how much difference the change in impedance makes in real world power handling.
Anyway, here's the original quote.
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