Hi all,

I've been thinking about making a nixie tube graphic equaliser in my head. It would make sense that the scale displayed on the nixie bar graph would be log, or than is how our ears perceive loudness. I did a bit of research, and came across RMS to DC converter ICs, which seemed to do this quite well, however, they also cost quite a bit, especially when you consider buying one for each nixie tube.

Is there a means by which one can make an RMS to DC converter cheaply (<$5)? Or is there perhaps another way that could achieve what I am after?

Many thanks for your time,

Sparky

 

I don't think RMS is what you want. I think you transformer couple the audio signal, rectify it and peak detect it with a fast attack and a slow decay. Think of the opening to the 9th Symphony. Three staccato attacks followed the decay. In RMS it will look like mush.

 

I agree, RMS is not what you want. A good peak detecter with an adjustable decay would work well for your application. A search for "op-amp peak detector circuit" will give you a lot of examples and even a youtube video or two.

 

Perfect, many thanks guys.

Peak detector it is.

 

Don't forget the bandpass filters. You'll need a bunch of them too.

 

Hello,

You might want to have a look at this project of ESP for the filters and detectors:
http://sound.westhost.com/project136.htm

Bertus