_dontaskwhy 10+ year member
Member
Like the title says. the flapping noise is it bottoming out or clipping bad. Been playing for about 30 minutes full tilt coming from work. Amp and sub were warm
I get that a clipped sine wave is no problem (electrically) for a preamp signal because the voltage and current in those signals is not moving a motor that generates heat and, consequently, impedance fluctuations. However, I'm a bit confused over your description of clipping as being no problem in the final amplification stage. As I've always understood it, a clipped sine wave becomes a long term DC signal and as such, causes the amplifier to have to stop and hold the coil at an extreme until the distorted portion of the sine wave falls below distortion. And I think it's pretty well accepted that DC current running through an AC motor tends only to dissipate it's energy as heat and thus, coil damage.Bottoming out. This forum and it's obsession with "clipping" is ridiculous. All clipping is, in a nutshell is an amp putting out maximum power over a longer period of time than intended by the source. The points that were already maximum end up creating higher order distortion at that point, which is just higher frequencies that didn't exist in the original source. So what used to be a pure 40hz wave for example will have 80hz, 160hz, 320hz content in it. Most subwoofers inductance will simply filter out the higher order harmonics so they wont' even be heard. The main damage it causes to a sub is simply by power over time as now when the amp might have only put out max power for 2 seconds before the signal fell, it'll hold max power, even on quiter passages, hence it fries coils.. Regardless clipping isn't inherently dangerous, you could clip the preamp all to hell for example and make the same signal you'd see out of the amp by clipping it all to hell. Only difference now is that waveform would exist at ALL volume levels and get worse if you then clipped the output side too. However, at low volume levels it wouldn't be any more harmful than anything else to a speaker. Again, tweets you'd want to watch it, since those higher order harmonics would add more POWER OVER TIME, which can fry a tweeter...
Sure can.. First, don't think of the amplitude of a wave as cone position, think of it purely in terms of acceleration. If you've taken a physics class you know acceleration is velocity over time. It has a direction, so a car can be moving forwards (velocity) while accelerating backwards (slowing down) Speakers behave the same.. At the + peak of the sinewave, which way is the cone moving? Most people would say it's still... WRONG It's moving forward, because that's the direction it was moving a split second before max voltage. All the peak means is you aren't addding any new voltage and will be starting to add less. If you let off the gas does your car stop dead? It's going to continue moving that direction until the force of the suspension and the magnet pulling the other once the signal switches overcomes the speakers forward momentum.. Just after the peak on the way back down, which way is the cone moving.. Again, still forward, until opposing force can pull it the other way, however it is now accelerating backwards as it's moving forward, slower than before, like breaks on a car..... It's accelerating backwards, but moving forwards.. The cone is always moving.. Even if you apply DC, if your suspension was able to travel forever outwards, the cone would keep moving. So your cone is ALWAYS moving. Realize this all happens VERY quickly, 20-80 times per second it will do a full cycle so 40-160 times per second for each half of the wave.. Not alot of time factor at any point, but hopefully this sheds like on what the speaker is really doing with the signal it's given.I get that a clipped sine wave is no problem (electrically) for a preamp signal because the voltage and current in those signals is not moving a motor that generates heat and, consequently, impedance fluctuations. However, I'm a bit confused over your description of clipping as being no problem in the final amplification stage. As I've always understood it, a clipped sine wave becomes a long term DC signal and as such, causes the amplifier to have to stop and hold the coil at an extreme until the distorted portion of the sine wave falls below distortion. And I think it's pretty well accepted that DC current running through an AC motor tends only to dissipate it's energy as heat and thus, coil damage.
Can you help clear up my confusion?
some good sh.t thereSure can.. First, don't think of the amplitude of a wave as cone position, think of it purely in terms of acceleration. If you've taken a physics class you know acceleration is velocity over time. It has a direction, so a car can be moving forwards (velocity) while accelerating backwards (slowing down) Speakers behave the same.. At the + peak of the sinewave, which way is the cone moving? Most people would say it's still... WRONG It's moving forward, because that's the direction it was moving a split second before max voltage. All the peak means is you aren't addding any new voltage and will be starting to add less. If you let off the gas does your car stop dead? It's going to continue moving that direction until the force of the suspension and the magnet pulling the other once the signal switches overcomes the speakers forward momentum.. Just after the peak on the way back down, which way is the cone moving.. Again, still forward, until opposing force can pull it the other way, however it is now accelerating backwards as it's moving forward, slower than before, like breaks on a car..... It's accelerating backwards, but moving forwards.. The cone is always moving.. Even if you apply DC, if your suspension was able to travel forever outwards, the cone would keep moving. So your cone is ALWAYS moving. Realize this all happens VERY quickly, 20-80 times per second it will do a full cycle so 40-160 times per second for each half of the wave.. Not alot of time factor at any point, but hopefully this sheds like on what the speaker is really doing with the signal it's given.
Now think of the sine wave signal again realizing the speaker is always moving. The x axis shows time, the Y axis is instantaneous voltage at any given point, right? CORRECT! haha. Anyways, if you want to calculate TOTAL power over time, you'd integrate, using calculus. If you've taken that you know it's simply area under the curve. So with 2 voltage charts, whichever area you could "shade in" more of with a pencil, has more total voltage over time and power applied.. That's where the clipped signal blows speakers. Where a non clipped signal wouldn't be putting out peak voltage, a clipped signal will be, so more power over time. That's not to say it's inherently any more dangeous than a clean signal at higher power however...
So if you clip the preamp signal and run it just under clipping at the output stage you can get the same cone movement by clipping the output stage and having a clean preamp signal.. Advantage would actually be to the clipped output here since it would have less power over time at lower volume levels, where it hasn't clipped yet.. If your going to clip, clip as late as possible in the gain stage. That way it's only amplified once and your not clipping an already clipped signal as that could sound bad at all volumes.