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<blockquote data-quote="thch" data-source="post: 1534657" data-attributes="member: 562032">for the simple dector, its only up to the DMM used, maybe within some noise limits (the circuit i made is very noisy, measuing about 3mV AC at lowest.)&nbsp; for reference, high clipping measured about 600mV, but clipping was detected at 15mV.&nbsp; this is for a 20V peak signal.basically, a sound wave is played which increases linearly.&nbsp; if the DMM&#039;s reading starts to increase quickly, then there is distortion.but you should be able to use the amp to give some gain to the preamp signal so you can get something measurable on a DMM.&nbsp; but active filters can probably give higher resolution.&nbsp; the issue with a passive filter is the you can have no complex poles.&nbsp; thus my bandstop filter will block 60hz (by a factor exceeding 1000), but also blocks 180hz by a factor of 2.&nbsp; if I could boost 180hz by a factor of 100, the resolution of the circuit could improve.&nbsp; as it stands, it picks up very low levels of compression.&nbsp; the OScope coupled with the sensor picked up on the distortion well before it was visually apparent on a real OScope (not a handheld with limited screen resolution).an on board clipping detector is more generic and can work on more signals.&nbsp; this only works for certain test tones.&nbsp; my test used 50 and 60hz tones.&nbsp; 50hz does not work as well as 60hz because the distortion component at 150hz is more attenuated then the distortion at 180hz.&nbsp; it is the 3rd harmonic that I am most interested in.</blockquote>

[QUOTE="thch, post: 1534657, member: 562032"] for the simple dector, its only up to the DMM used, maybe within some noise limits (the circuit i made is very noisy, measuing about 3mV AC at lowest.) for reference, high clipping measured about 600mV, but clipping was detected at 15mV. this is for a 20V peak signal. basically, a sound wave is played which increases linearly. if the DMM's reading starts to increase quickly, then there is distortion. but you should be able to use the amp to give some gain to the preamp signal so you can get something measurable on a DMM. but active filters can probably give higher resolution. the issue with a passive filter is the you can have no complex poles. thus my bandstop filter will block 60hz (by a factor exceeding 1000), but also blocks 180hz by a factor of 2. if I could boost 180hz by a factor of 100, the resolution of the circuit could improve. as it stands, it picks up very low levels of compression. the OScope coupled with the sensor picked up on the distortion well before it was visually apparent on a real OScope (not a handheld with limited screen resolution). an on board clipping detector is more generic and can work on more signals. this only works for certain test tones. my test used 50 and 60hz tones. 50hz does not work as well as 60hz because the distortion component at 150hz is more attenuated then the distortion at 180hz. it is the 3rd harmonic that I am most interested in. [/QUOTE]

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