speaker pop attenuation
Bookmark this page:
 Yahoo!
 Google
 Windows Live
 del.icio.us
 digg
 Netscape
|
|
|||||||||||||||||||
|
Posted by mw on June 12, 2005, 6:22 pm
Please log in for more thread options What causes speaker pop in audio amplifiers? The "pop" occurs when the amp is first turned on. It also can occur as the amp is turned off. What is a good strategy to prevent it, especially for a MOSFET amplifier design? I think I read somewhere that it is caused when the speaker is driven but voltages haven't yet attained their stable points. If that is true is there a good way to clamp intermediate stages for a while till all the voltages are stable? Like with a FET or an analog switch? My review of amplifier designs and my own use of available products I see that: "Build it yourself" amp articles on the Internet usually don't even mention that speaker pop exists. I assume this is because 1) they are experimental and the main goal is just getting them to work at all... and 2) It's just amusing reading material and no one usually builds them, so who cares? ;-) My guess is that tube amplifiers don't suffer from this because at first turn-on the tubes aren't heated enough to drive the speaker hard enough. Maybe they do pop if you warm them up a long time then cycle power. I don't have one to experiment with. Looking at guitar schematics I do not see any special circuitry to address speaker pop. Maybe the guitarists always turn the amp gain all the way to zero every time, or maybe there is a standby switch on some tube amps. Both my home audio tuner amps (an Onkyo and a Sony) have some sort of elaborate speaker loading detection circuit involving a relay. I can hear it clicking, and there is an annoying delay. I don't recall anything like this in my old Kenwood tuner amp. I think most simple amps, like a solid state keyboard amp I have, just hit the speaker with a big pop at start-up, a smaller pop at turn off, and the owner just learns to ignore it. It probably is tough on the speaker, but it is a "cheap" work-around... do nothing. | |||||||||||||||||||
|
Posted by Paul Mathews on June 12, 2005, 11:45 am
Please log in for more thread options Yes, speaker pop is due to transient phenomena at power up and down. In some amplifiers, it has to do with stabilization of the power supplies. In others, there is a large capacitor in series with the output that has to be charged to half the supply voltage, in effect, through the speaker load. The better amps include a relay and a time delay...usually nothing more sophisticated than that. Some amps have more elaborate circuitry to limit current to the output stage, thereby stretching out the transients and making them inaudible. There's seldom enough energy involved to damage a loudspeaker. Paul Mathews mw wrote: | |||||||||||||||||||
|
Posted by Graham Holloway on June 13, 2005, 11:25 am
Please log in for more thread options
> What causes speaker pop in audio amplifiers? The "pop" occurs when the
> amp is first turned on. It also can occur as the amp is turned off. > What is a good strategy to prevent it, especially for a MOSFET amplifier > design? > > I think I read somewhere that it is caused when the speaker is driven > but voltages haven't yet attained their stable points. If that is true > is there a good way to clamp intermediate stages for a while till all > the voltages are stable? Like with a FET or an analog switch? > > My review of amplifier designs and my own use of available products I > see that: > > "Build it yourself" amp articles on the Internet usually don't even > mention that speaker pop exists. I assume this is because 1) they are > experimental and the main goal is just getting them to work at all... > and 2) It's just amusing reading material and no one usually builds > them, so who cares? ;-) > > My guess is that tube amplifiers don't suffer from this because at first > turn-on the tubes aren't heated enough to drive the speaker hard enough. > Maybe they do pop if you warm them up a long time then cycle power. > I don't have one to experiment with. Looking at guitar schematics I do > not see any special circuitry to address speaker pop. Maybe the > guitarists always turn the amp gain all the way to zero every time, or > maybe there is a standby switch on some tube amps. > > Both my home audio tuner amps (an Onkyo and a Sony) have some sort of > elaborate speaker loading detection circuit involving a relay. I can > hear it clicking, and there is an annoying delay. I don't recall > anything like this in my old Kenwood tuner amp. > > I think most simple amps, like a solid state keyboard amp I have, just > hit the speaker with a big pop at start-up, a smaller pop at turn off, > and the owner just learns to ignore it. It probably is tough on the > speaker, but it is a "cheap" work-around... do nothing. > > > > > > I find that the easiest way to minimise the pop is to design the amplifier to operate over the widest supply voltage range possible. With this normally comes the rejection of mains ripple and its modulation by the other channel in a stereo system. Graham Holloway | |||||||||||||||||||
| Similar Threads | Posted |
| speaker pop attenuation | June 12, 2005, 6:22 pm |
| Attenuation of op-amp gain | March 31, 2005, 3:53 am |
| Convert 10dbU to 4dbV with attenuation | October 18, 2006, 6:25 pm |
| Audio input, why need gain and attenuation? | December 7, 2006, 10:32 am |
| Different shield types and noise attenuation | June 6, 2007, 10:18 pm |
| Attenuation and signal conditioning circuit | November 18, 2007, 6:59 am |
| Speaker Questions | October 9, 2005, 2:56 pm |
| speaker isolation | January 30, 2006, 6:50 pm |
| speaker isolation | January 30, 2006, 6:51 pm |
| PICMICRO --> 1hz speaker | October 13, 2006, 4:30 am |
| "new" speaker idea | November 16, 2006, 1:49 pm |
| speaker source | May 21, 2007, 1:42 pm |
| Wavelength and speaker | October 19, 2007, 12:12 pm |
| Driving 8 Ohm speaker from pic pwm pin | February 7, 2008, 1:46 pm |
| Speaker Recognition | July 5, 2008, 2:02 am |
> amp is first turned on. It also can occur as the amp is turned off.
> What is a good strategy to prevent it, especially for a MOSFET amplifier
> design?
>
> I think I read somewhere that it is caused when the speaker is driven
> but voltages haven't yet attained their stable points. If that is true
> is there a good way to clamp intermediate stages for a while till all
> the voltages are stable? Like with a FET or an analog switch?
>
> My review of amplifier designs and my own use of available products I
> see that:
>
> "Build it yourself" amp articles on the Internet usually don't even
> mention that speaker pop exists. I assume this is because 1) they are
> experimental and the main goal is just getting them to work at all...
> and 2) It's just amusing reading material and no one usually builds
> them, so who cares? ;-)
>
> My guess is that tube amplifiers don't suffer from this because at first
> turn-on the tubes aren't heated enough to drive the speaker hard enough.
> Maybe they do pop if you warm them up a long time then cycle power.
> I don't have one to experiment with. Looking at guitar schematics I do
> not see any special circuitry to address speaker pop. Maybe the
> guitarists always turn the amp gain all the way to zero every time, or
> maybe there is a standby switch on some tube amps.
>
> Both my home audio tuner amps (an Onkyo and a Sony) have some sort of
> elaborate speaker loading detection circuit involving a relay. I can
> hear it clicking, and there is an annoying delay. I don't recall
> anything like this in my old Kenwood tuner amp.
>
> I think most simple amps, like a solid state keyboard amp I have, just
> hit the speaker with a big pop at start-up, a smaller pop at turn off,
> and the owner just learns to ignore it. It probably is tough on the
> speaker, but it is a "cheap" work-around... do nothing.