Feedback
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- gregtarr
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- meble-kuchenne.warszawa.pl
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Feedback
I have a question. What actually happens when you get feedback?
Both microphonic, and the regular sort.
Both microphonic, and the regular sort.
- ash
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Feedback of any sort means that in some way the output signal (sound, vibration, electrical etc...) is feeding back to the input source.
In the case of microphonic feedback of valves and pickups, the sound level produced by the speakers is enough to physically vibrate the unrestrained wires and plates inside the valve/pickup. If the vibration is enough it can influence the operation of the device and induce a signal of its own, which is usually a howling sound.
Guitar (or microphone) feedback works the same way, except that the sound level (vibrations of the air) is assiting the vibration of the strings (or microphone diaphragm), casing their natural amplitude to increase. In this case the frequencies of resonance and feedback signals have to match more closely.
The other one you may not know about is that feedback is the primary control method within your amplifier. Gain across any preamplifier stage is controlled by feeding the output signal back into the input, but reversed so tht it cancels out the input. By controlling the amount of signal fed back you control the gain. Tone controls usually work the same way, by feeding back certain frequency ranges to limit the gain on that specific range...
In the case of microphonic feedback of valves and pickups, the sound level produced by the speakers is enough to physically vibrate the unrestrained wires and plates inside the valve/pickup. If the vibration is enough it can influence the operation of the device and induce a signal of its own, which is usually a howling sound.
Guitar (or microphone) feedback works the same way, except that the sound level (vibrations of the air) is assiting the vibration of the strings (or microphone diaphragm), casing their natural amplitude to increase. In this case the frequencies of resonance and feedback signals have to match more closely.
The other one you may not know about is that feedback is the primary control method within your amplifier. Gain across any preamplifier stage is controlled by feeding the output signal back into the input, but reversed so tht it cancels out the input. By controlling the amount of signal fed back you control the gain. Tone controls usually work the same way, by feeding back certain frequency ranges to limit the gain on that specific range...
http://ashcustomworks.com for custom built electric guitars hand made in new zealand
- Bg
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Which is why some humbuckers are wax 'potted' within the cover, to fix the coils etc securely in place so that no vibration can be induced - causing the microphonic feedback.ash wrote:In the case of microphonic feedback of valves and pickups, the sound level produced by the speakers is enough to physically vibrate the unrestrained wires and plates inside the valve/pickup. If the vibration is enough it can influence the operation of the device and induce a signal of its own, which is usually a howling sound.
So, is that low alcohol or no alcohol at all? mmmm, no alcohol, do you want to try it? Noooooooooo.
- angry_young_poet
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- ash
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Yes, too much gain can cause it. Lower the volume, point the mic away, move it further away or drop the EQ a bit.
My Tele neck pickup is rumoured to be a vintage Fender and it squeals like a hillbilly!
BTW, gain isn't another name for distortion or overdrive. Gain is to the pre-amp what Volume is to the power-amp. Its just how much the signal gets amplified. Even clean channels have gain...
The devious marketing people and dumbass magazine reviwers would like us to think that gain = distortion because they don't really understand themselves.
In reality gain = volume and lots-of-gain = distortion and lots-of-volume = feedback.
My Tele neck pickup is rumoured to be a vintage Fender and it squeals like a hillbilly!
BTW, gain isn't another name for distortion or overdrive. Gain is to the pre-amp what Volume is to the power-amp. Its just how much the signal gets amplified. Even clean channels have gain...
The devious marketing people and dumbass magazine reviwers would like us to think that gain = distortion because they don't really understand themselves.
In reality gain = volume and lots-of-gain = distortion and lots-of-volume = feedback.
Last edited by ash on Wed Jul 07, 2004 1:56 pm, edited 1 time in total.
http://ashcustomworks.com for custom built electric guitars hand made in new zealand
- ash
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The sound level from the amplifier is high enough to vibrate the loose parts inside a pickup or valve so that they act like a guitar string. Their vibration gets sent through the system and amplified too. It sounds like a loud squealing sound.angry_young_poet wrote:in layman's term?
Guitar feedback is where the amp sound makes the string itself vibrate on its own.
http://ashcustomworks.com for custom built electric guitars hand made in new zealand
- angry_young_poet
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