I am having a discussion with a friend that is under the understanding that class-D amplifiers are not good for bass/subwoofer use because they cannot sustain there power long term at low frequencies.
I remember reading some info on the B&O ice power modules something to that effect and that the newer tope of the line model corrected that somehow.
I am looking for info either direction on the issue to back up the argument either way.
The application would be a powered subwoofer or LF cabinet for Live sound use that will be used for Dance music that has quite a bit of sustained LF information.
I remember reading some info on the B&O ice power modules something to that effect and that the newer tope of the line model corrected that somehow.
I am looking for info either direction on the issue to back up the argument either way.
The application would be a powered subwoofer or LF cabinet for Live sound use that will be used for Dance music that has quite a bit of sustained LF information.
That's got nothing to do with class D as such, it is (mainly) a question of how the PSU is designed and sized. Many class D amps will have poor FTC-ratings because they don't have the same thermal inertia as a class AB amp and FTC is full power for 5 mins so the class D amp will overheat, but that is not the same as what your friend claims.
The ICEpower modules were in fact designed for PA active speaker applications and they are used in enough PA speakers from companies like DAS, EAW, Renkus-Heinz etc. that I believe they have proved they are up to the task.
/U.
The ICEpower modules were in fact designed for PA active speaker applications and they are used in enough PA speakers from companies like DAS, EAW, Renkus-Heinz etc. that I believe they have proved they are up to the task.
/U.
I think your friend is thinking of the wrong end of the spectrum. The early ICEpower amps couldn't do sustained high power out at HIGH frequencies. That is because they had a zobel in the output circuit, (needed to keep stable apparently), and the zobel would generate heat at high frequency. The resistor wasn't rated for high power, so the ICEpowers couldn't do sustained high power high frequency tones without damage. (Tweeters don't handle that well, either, so no real loss).
Many of big high powered high priced pro-sound subs are class-d these days.
http://www.jblpro.com/catalog/general/Product.aspx?PId=214&MId=4
As are many home theater plate amps and car sub amps winning competitions.
Low heat, high efficiency, much smaller heat sinks are needed.
http://www.jblpro.com/catalog/general/Product.aspx?PId=214&MId=4
As are many home theater plate amps and car sub amps winning competitions.
Low heat, high efficiency, much smaller heat sinks are needed.
There are a few different types of ICEpower amps:
The A and ASP series can sustain full power with the use of external cooling. I've tested the 1000ASP @ 1000W sinewave output for 30 minutes, no problem what so ever.
The ASC and ASX2 is a different story, as both the power supply and output stage is designed to deliver audio signals with no less than 9 dB (1/8) crest factor, which should be sufficient on full bandwidth audio signal.
The point is that most amps are designed for delivering music signals, not continous sinewave. There are many class AB amps that can't deliver sustained full power either because of insufficient cooling!
So - if you're into buying an ICEpower-based amp for live sound, look for one thats using the ASP modules.
And no - you cant buy ICEpower modules for DIY.
The A and ASP series can sustain full power with the use of external cooling. I've tested the 1000ASP @ 1000W sinewave output for 30 minutes, no problem what so ever.
The ASC and ASX2 is a different story, as both the power supply and output stage is designed to deliver audio signals with no less than 9 dB (1/8) crest factor, which should be sufficient on full bandwidth audio signal.
The point is that most amps are designed for delivering music signals, not continous sinewave. There are many class AB amps that can't deliver sustained full power either because of insufficient cooling!
So - if you're into buying an ICEpower-based amp for live sound, look for one thats using the ASP modules.
And no - you cant buy ICEpower modules for DIY.
Class-D Bass
I use Class-D amps in all my designs for a major pro audio company including our 1-18 Sub cabinets. We had 18 of these boxes with double 18s and 2 x 1000A ICE modules powering the subs in the basketball arena at the Olympics last year.
While Class D amps, because of the DC resistance of the inductors in the output, have in theory a slightly lower damping factor because we know this is there I am able to compensate for the effect. However, this does not affect the sheer output level and power of the bottom end. The bottom end depends more on the power supply design of the amplifier. Any amp, PWM or linear.
However, most power supply designers are driven wild by the varying demands of audio and have no clue how power supply design can affect the bass quality of an amplifier. The transient response for example if a huge factor in the bass quality of an amp. And there is no substitute for lots of big capacitors. But they must be wired correctly. I see so many amps where the capacitors are wired wrong which reduces their effectiveness by 95%.
So really, there is no reason why you cannnot get sustained bass with class D. I just find that most companies have contracted their design work to Asian suppliers and while the eople there are talented. I have found they think we are insane with the amounts of bottom end oomph we demand from our systems.
I use Class-D amps in all my designs for a major pro audio company including our 1-18 Sub cabinets. We had 18 of these boxes with double 18s and 2 x 1000A ICE modules powering the subs in the basketball arena at the Olympics last year.
While Class D amps, because of the DC resistance of the inductors in the output, have in theory a slightly lower damping factor because we know this is there I am able to compensate for the effect. However, this does not affect the sheer output level and power of the bottom end. The bottom end depends more on the power supply design of the amplifier. Any amp, PWM or linear.
However, most power supply designers are driven wild by the varying demands of audio and have no clue how power supply design can affect the bass quality of an amplifier. The transient response for example if a huge factor in the bass quality of an amp. And there is no substitute for lots of big capacitors. But they must be wired correctly. I see so many amps where the capacitors are wired wrong which reduces their effectiveness by 95%.
So really, there is no reason why you cannnot get sustained bass with class D. I just find that most companies have contracted their design work to Asian suppliers and while the eople there are talented. I have found they think we are insane with the amounts of bottom end oomph we demand from our systems.
Capacitor wiring
It a bunch of extra capa are mounter as a branch off the power wiring between the source and the amp, thatis where the charge and discharge path for the caps is the same conductor, their effectiveness will be greatly reduced.
The power, for both leads has to go from the source to the capacitors. Then from the capacitors to the load. That is, where the charge and discharge paths to and from the capacitors are separate conductors.
It a bunch of extra capa are mounter as a branch off the power wiring between the source and the amp, thatis where the charge and discharge path for the caps is the same conductor, their effectiveness will be greatly reduced.
The power, for both leads has to go from the source to the capacitors. Then from the capacitors to the load. That is, where the charge and discharge paths to and from the capacitors are separate conductors.
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