irbirb
Member
hello,
i just wanted to get some comments an this thing i built.
2 audio inputs are each split into highpass, lowpass, and bandpass via state-variable-filters. these operate on a single supply.
each of the six resulting audio channels drive six lm3915's.
the filtered audio had some weird DC offset things going on. the levels would be too high, but when measuring with a scope, the levels gradually drop to where i think they should be, centred around zero volts. i'm not really sure why this is.
i decided to try and clamp the driver chip inputs with a diode. it didn't work with a 1n4148 but a some kind of germanium diodes i have are doing the job well. they end up working as a sort of peak/average which makes the LEDs brighter in general and a resistor in parallel allows for a level of adjustability... a higher value holds the peaks longer... at least i think that's what is going on.
i just wanted to get some comments an this thing i built.
2 audio inputs are each split into highpass, lowpass, and bandpass via state-variable-filters. these operate on a single supply.
each of the six resulting audio channels drive six lm3915's.
the filtered audio had some weird DC offset things going on. the levels would be too high, but when measuring with a scope, the levels gradually drop to where i think they should be, centred around zero volts. i'm not really sure why this is.
i decided to try and clamp the driver chip inputs with a diode. it didn't work with a 1n4148 but a some kind of germanium diodes i have are doing the job well. they end up working as a sort of peak/average which makes the LEDs brighter in general and a resistor in parallel allows for a level of adjustability... a higher value holds the peaks longer... at least i think that's what is going on.