Isn’t it because you have two coils vs one and each coil has to move less weight is that correct?
There are a few reasons why people don't employ 18" drivers in a home system. The 18" is a lot slower in response, the 18" demands a large box even if tuned electronically. The 18" will demand a large amout of power. Two 15" will generally kick the pants off a good 18" driver. The 15" drivers will be quicker and more accurate and use less power in the process. They will generally be cheaper but this is not always the case.
In commercial applications like football stadiums it is not uncommon to have an array of say 18-30 dual 18" speaker cabinets for the low end. Then again they are not trying to go down to say 20HZ either. It isn't uncommon to have in the range of 1000-1200 watts per driver either.
If you can afford the purchase of a high powered amp or build one. The real estate loss for the box. The wife negative approval factor. Then go ahead with an 18 or larger driver.
In commercial applications like football stadiums it is not uncommon to have an array of say 18-30 dual 18" speaker cabinets for the low end. Then again they are not trying to go down to say 20HZ either. It isn't uncommon to have in the range of 1000-1200 watts per driver either.
If you can afford the purchase of a high powered amp or build one. The real estate loss for the box. The wife negative approval factor. Then go ahead with an 18 or larger driver.
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How about an isobaric configuration which halves the volume requirement? The earth will move
Granted, a valid point. Still one has to consider the velocity of the 18 cones as opposed to that of the 15". The 18" driver still sound unholy because of the slowness.
The EVX-180 was a prime example of one of the better 18" low frequency drivers because of its electrical parimeters and very long Xmax. The QTS of the driver allows for it to be electronically jammed into a smaller box (6 cu ft)and go down to about 24 Hz and play all day. While able to put a smile on ones face when watching an action movie it just wasn't able to deliver the bass passages in a CD with precision.
How about an isobaric configuration which halves the volume requirement? The earth will move
Granted, a valid point. Still one has to consider the velocity of the 18 cones as opposed to that of the 15". The 18" driver still sound unholy because of the slowness.
The EVX-180 was a prime example of one of the better 18" low frequency drivers because of its electrical parimeters and very long Xmax. The QTS of the driver allows for it to be electronically jammed into a smaller box (6 cu ft)and go down to about 24 Hz and play all day. While able to put a smile on ones face when watching an action movie it just wasn't able to deliver the bass passages in a CD with precision.
consort_ee_um said:
A better way and less expensive is to use a little box with a boost at very low frequency
Regards,
Avi
I'm no expert here, but I honestly think the whole thing about 18" drivers having a "slow response" is B.S.
If designed properly (powerfull magnet structure, stiff cone, 5" or 6" voice coil, etc, etc...), an 18" driver can perform just as "quick" as a 15" driver all day long.
For quite a while, I used a Klipsch 18" driver in a sealed 9 cu.ft enclosure powered by a Carver Pro PM-700 amp (700watts mono @ 8 ohms). I was using this sub with a pair of Magnepans at the time, and even with a pair of Klipsch Cornwalls and that sub had absolutely no problems keeping up with either pair of speakers. In fact, I brought home a Sunfire True Sub and an M&K with dual 12" drivers, and neither one of them could keep pace with the Maggies, but that Klipsch 18" sub that I built did it effortlessly.
Granted, most of the regular speaker companies out there just take the motor structure and VC of a 12" or 15" driver, and strap it to an 18" basket and cone. Naturally these are going to perform like cra-pooh since that motor structure wasn't designed for the larger and heavier cone. So comparisons of these types of 18" drivers shouldn't even be considered.
If you compare an honest, purpose built 18" driver to a typical but good quality 15" driver, I bet you that 18" driver will outperform the 15. 😉
If designed properly (powerfull magnet structure, stiff cone, 5" or 6" voice coil, etc, etc...), an 18" driver can perform just as "quick" as a 15" driver all day long.
For quite a while, I used a Klipsch 18" driver in a sealed 9 cu.ft enclosure powered by a Carver Pro PM-700 amp (700watts mono @ 8 ohms). I was using this sub with a pair of Magnepans at the time, and even with a pair of Klipsch Cornwalls and that sub had absolutely no problems keeping up with either pair of speakers. In fact, I brought home a Sunfire True Sub and an M&K with dual 12" drivers, and neither one of them could keep pace with the Maggies, but that Klipsch 18" sub that I built did it effortlessly.
Granted, most of the regular speaker companies out there just take the motor structure and VC of a 12" or 15" driver, and strap it to an 18" basket and cone. Naturally these are going to perform like cra-pooh since that motor structure wasn't designed for the larger and heavier cone. So comparisons of these types of 18" drivers shouldn't even be considered.
If you compare an honest, purpose built 18" driver to a typical but good quality 15" driver, I bet you that 18" driver will outperform the 15. 😉
chops said:
A sine wave only needs so much slewing from the cone.
Unless you have a poor cross-over or try to operate the cone at too high a frequency, 'slowness' is a nonissue.
18" are excellent for *deep* bass.
the theory behind "larger cones have more mass and move slower etc..." has had a formal proof written why this concept alone is false. *Done by dan wiggins at adire audio if you werent familiar with that work*
Now step response(basically how the cone stops moving) will be affected. Therefore some subjective slowness and muddyness can be percieved, BUT as stated earlier by others I also believe this is the fault of skimpy motor.
Now step response(basically how the cone stops moving) will be affected. Therefore some subjective slowness and muddyness can be percieved, BUT as stated earlier by others I also believe this is the fault of skimpy motor.
Quote:
the theory behind "larger cones have more mass and move slower etc..." has had a formal proof written why this concept alone is false. *Done by dan wiggins at adire audio if you werent familiar with that work*
Please do paste a link to this formal written proof.
the theory behind "larger cones have more mass and move slower etc..." has had a formal proof written why this concept alone is false. *Done by dan wiggins at adire audio if you werent familiar with that work*
Please do paste a link to this formal written proof.
I'm glad to see that others here agree with me. 😀
I was actually thinking that I was going to get hammered for making such a statement.
Seriously though, if done correctly, it shouldn't matter what size the cone is. Look at that 6 foot tall woofer that David Clark built a while back. The motor structure on that thing is the size and weight of a Yugo! If I remember correctly, it used something like a 12" or 15" VC as well!
It's just like with cars. In order for a 2400lb 1967 Shelby Cobra to go from 0-100mph and back to 0mph in under 13 seconds, it only needs 425hp to do so. You can do the same thing with a 5000lb 1977 Lincoln Town Car, except you'll need about 1200hp and massive 15" brakes to do it, but it can be done. 😉
I was actually thinking that I was going to get hammered for making such a statement.
Seriously though, if done correctly, it shouldn't matter what size the cone is. Look at that 6 foot tall woofer that David Clark built a while back. The motor structure on that thing is the size and weight of a Yugo! If I remember correctly, it used something like a 12" or 15" VC as well!
It's just like with cars. In order for a 2400lb 1967 Shelby Cobra to go from 0-100mph and back to 0mph in under 13 seconds, it only needs 425hp to do so. You can do the same thing with a 5000lb 1977 Lincoln Town Car, except you'll need about 1200hp and massive 15" brakes to do it, but it can be done. 😉
BassAwdyO said:
Actually, I goofed on the name. His name is Richard Clark, not David. And I have been looking on Google left and right and cannot find anything about it right now, but it is out there. 😉
Chops is correct.
if it had a 6” coil it would kick I’ve seen a 100” sub in the back of a semi truck I think, it doesn’t matter what size you have to scale up everything in theory the driver should work better.
I have found a sub box that uses 2 100inch woofers😱 give me😀
if it had a 6” coil it would kick I’ve seen a 100” sub in the back of a semi truck I think, it doesn’t matter what size you have to scale up everything in theory the driver should work better.
I have found a sub box that uses 2 100inch woofers😱 give me😀
Hayden said:
With some active correction I can get a -3dB point at 15Hz in my room. 😎
An externally hosted image should be here but it was not working when we last tested it.
Re: Tony talk to me!
They are Precision Devices PD2150's. More info here:
PD2150 in various boxes
J.k.Wilson said:
They are Precision Devices PD2150's. More info here:
PD2150 in various boxes
chops said:I'm glad to see that others here agree with me. 😀
I was actually thinking that I was going to get hammered for making such a statement.
Seriously though, if done correctly, it shouldn't matter what size the cone is. Look at that 6 foot tall woofer that David Clark built a while back. The motor structure on that thing is the size and weight of a Yugo! If I remember correctly, it used something like a 12" or 15" VC as well!
It's just like with cars. In order for a 2400lb 1967 Shelby Cobra to go from 0-100mph and back to 0mph in under 13 seconds, it only needs 425hp to do so. You can do the same thing with a 5000lb 1977 Lincoln Town Car, except you'll need about 1200hp and massive 15" brakes to do it, but it can be done. 😉
I also agree, I believe it is all down to the Bl/Mms ratio (considering the cone is made stiff enough). The PD2150 has a Bl of 34.28 and an Mms of 305 grams, this results in an accleration factor of 112. For example the often used 12" Peerless XLS12 has an acceleration factor of 106 and less than only a third of the cone area.
BassAwdyO said:
some pics can be found here http://www.carsound.com/UBB/ultimatebb.php?ubb=get_topic;f=1;t=023699;p=3
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