Also, for what it's worth, comparing the McCauley 6174 to the Stryke AV15 is an unfair comparison. Due to the extra cone area, it's always easier to get higher efficiency numbers with an 18" than a 15", all other things being equal.
Someone also asked why anyone would want an AV15 over a 6174. The answer is that if you had a choice of either being given to you, of course you'd choose the 6174, just like you'd choose a BMW 7 series versus a Kia Rio if given the choice.
Having said that, the 6174 is $828 and the AV15 is $205 list or $165 preorder. That's not just a little price difference, that's HUGE.
Even if you take it at the $205 list price, you can get four AV15's wired in series/parallel for less than the price of a single 6174.
If you put the 4 AV15's in the same box size as you would the 6174, the AV15's would destroy the 6174 in every possible way - power handling, resistance to power compression, maximum output, distortion, efficiency (yes, efficiency!) - you name it, the AV15 beats it.
It should also be noted that the efficiency of a subwoofer driver is one of the least important quantities to look at, at least when you're looking for a "pure" subwoofer driver and not a woofer for a 3-way that happens to go deep as well.
In most cases, the efficiency of a subwoofer system (enclosure and driver) tends to be dominated by the enclosure in the 5-40hz region. Higher reference efficiency does help, but nowhere near as much as you might think.
Someone also asked why anyone would want an AV15 over a 6174. The answer is that if you had a choice of either being given to you, of course you'd choose the 6174, just like you'd choose a BMW 7 series versus a Kia Rio if given the choice.
Having said that, the 6174 is $828 and the AV15 is $205 list or $165 preorder. That's not just a little price difference, that's HUGE.
Even if you take it at the $205 list price, you can get four AV15's wired in series/parallel for less than the price of a single 6174.
If you put the 4 AV15's in the same box size as you would the 6174, the AV15's would destroy the 6174 in every possible way - power handling, resistance to power compression, maximum output, distortion, efficiency (yes, efficiency!) - you name it, the AV15 beats it.
It should also be noted that the efficiency of a subwoofer driver is one of the least important quantities to look at, at least when you're looking for a "pure" subwoofer driver and not a woofer for a 3-way that happens to go deep as well.
In most cases, the efficiency of a subwoofer system (enclosure and driver) tends to be dominated by the enclosure in the 5-40hz region. Higher reference efficiency does help, but nowhere near as much as you might think.
Not a single AV15, no. Then again, the 6174 wouldn't either. There are very few drivers out there that can take 2200W RMS for any length of time, and none that I know of that can do it in a sealed box.
If you fed 4 AV15's total with a 2200W amplifier, though, they should be quite happy.
Like any driver, if you give them that 2200W at 100% duty cycle, they will run into power compression issues, but that's to be expected with *any* driver being run at those power levels.
If you fed 4 AV15's total with a 2200W amplifier, though, they should be quite happy.
Like any driver, if you give them that 2200W at 100% duty cycle, they will run into power compression issues, but that's to be expected with *any* driver being run at those power levels.
You're absolutely correct. One Labhorn is two 12" drivers though, and is also horn-loaded, which is an entirely different beast than the direct radiators we were discussing here.
It should also be noted that the sensitivity of the LAB12 driver is 87.4dB/W/M - the enclosure in this case is what gives you the incredible efficiency, not the reference efficiency of the driver.
It should also be noted that the sensitivity of the LAB12 driver is 87.4dB/W/M - the enclosure in this case is what gives you the incredible efficiency, not the reference efficiency of the driver.
As always, it depends. If the objective the driver is just a subwoofer, there is no substitute for volume displacement--as others already pointed out, it takes surprising little voltage to bottom a woofer at 20Hz.
On the other hand, if the driver is used for mid/mid bass, then the problem with large overhangs is it usually means large inductance. Large inductance generates flux modulation distortion. The nasty thing about flux modulation dstortion is that it's a problem even at low levels. Displacement related distortion products decrease at a fixed rate as SPL goes down: 2nd order products distortion drops 12dB when the fundamental drops 6dB. 3rd order distortion drops 18dB, fourth order 24dB, etc. The nice thing about displacement related distortion products is you can reduce them to an arbitrarily small level simply by oversizing everything. Horn loading and lots of drivers are nice for this: my speakers have 1 2" compression tweeter, 4 5" mids, 4 10" mid-bass, and a Servodrive contrabass sub.
Once you've givien yourself lot's of volume displacement, though, it's flux modulation distortion and suspension hysterisis distortion that are the problems. These distortion products (as a % of fundamental) at first fall as output is reduced, but then level off or even increase as SPL goes down. They're not so easy to fix either. Anything you can do to reduce driver inductance also results in lower flux modulation, so that's one easy parameter to look for when choosing drivers. Unfortunately the methods used to reduce inductance and flux modulation are also expensive. Certainly a cheap driver with a big overhang is going to have a big inductance and lots of flux modulation.
So bringing this back to the original question...big overhangs are not so good if they result in high inductance AND it's not just a subwoofer.
John
On the other hand, if the driver is used for mid/mid bass, then the problem with large overhangs is it usually means large inductance. Large inductance generates flux modulation distortion. The nasty thing about flux modulation dstortion is that it's a problem even at low levels. Displacement related distortion products decrease at a fixed rate as SPL goes down: 2nd order products distortion drops 12dB when the fundamental drops 6dB. 3rd order distortion drops 18dB, fourth order 24dB, etc. The nice thing about displacement related distortion products is you can reduce them to an arbitrarily small level simply by oversizing everything. Horn loading and lots of drivers are nice for this: my speakers have 1 2" compression tweeter, 4 5" mids, 4 10" mid-bass, and a Servodrive contrabass sub.
Once you've givien yourself lot's of volume displacement, though, it's flux modulation distortion and suspension hysterisis distortion that are the problems. These distortion products (as a % of fundamental) at first fall as output is reduced, but then level off or even increase as SPL goes down. They're not so easy to fix either. Anything you can do to reduce driver inductance also results in lower flux modulation, so that's one easy parameter to look for when choosing drivers. Unfortunately the methods used to reduce inductance and flux modulation are also expensive. Certainly a cheap driver with a big overhang is going to have a big inductance and lots of flux modulation.
So bringing this back to the original question...big overhangs are not so good if they result in high inductance AND it's not just a subwoofer.
John
As the speaker approaches the limits of xmax, it becomes non linear, mechanically compressing the signal. By not driving it to extremes a more accurate linearity is achieved.
One company has designed an integrated driver, cones at 22, 30 and 40 inches with an xmax of nearly 3 inches and an integrated amp with an rms of 5000 watts, 45000 peak with integrated ESP processing that guarantees an output wave exactly the same as the input wave in linearity, and phase with 97% efficiency.
I'd want to see a lot of evidence to even consider that an electro-acoustic transducer might achieve 97%. Seriously. 50% for big horns at impedance peaks is the highest I've heard of, and only happens for a bandwidth of a few Hz.
As for the 45KW peak power handling, that's about right. The demands of the pro audio industry are shifting towards extreme LF power density. If you can have a quantity of four 40" drivers and that will replace a big pile of double-18" cabs, you know which everyone is going to go for.
Power is cheap, trucks are expensive.
Chris
I'm guessing it is M-Force, and it is the amp that's 97% efficient - it's one of those "eats, shoots and leaves" problems.
I added some punctuation / emphasis to the original statement.
One company has designed:
an integrated driver
- cones at 22, 30 and 40 inches
- with an xmax of nearly 3 inches
and an integrated amp
- with an rms of 5000 watts, 45000 peak
- with integrated ESP processing that guarantees an output wave exactly the same as the input wave in linearity and phase
- with 97% efficiency.
It got integrated twice (at the department of redundancy department), but otherwise is pretty clear
I added some punctuation / emphasis to the original statement.
One company has designed:
an integrated driver
- cones at 22, 30 and 40 inches
- with an xmax of nearly 3 inches
and an integrated amp
- with an rms of 5000 watts, 45000 peak
- with integrated ESP processing that guarantees an output wave exactly the same as the input wave in linearity and phase
- with 97% efficiency.
It got integrated twice (at the department of redundancy department), but otherwise is pretty clear
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