VU Meter

[Deltat]

Im looking to add a VU meter to this project im working on. Its a simple audio demonstration project my professor wants to use to demonstrate some of the things we do in our major. It will run off of 2 batteries with a switching regulator to output +12V. It will then go through one of 3 filters LP, BP or HP, then a 10W amplifier. The only thing im confused on is how to add a VU meter to this project. Suggestions?

Kurt

 

[SY]

IIRC, National Semiconductor makes some dedicated VU meter chips with LED output. Check their site.

 

[Mr Evil]

I documented a VU meter I made on my site.

 

[Da5id4Vz]

Are you looking for a meter to make actual measurements with?

Volume Units are tightly designed for both attack and decay response of the display. Originally a Western Electric galvanometer mechanism and later as displayed in LED lights.

"0 Vu" also is also defined by specific reference levels (-10, +4 and +8 dB). Each has a definition or how the meter is bridged across an audio load to make its appropriate measurement.

A reference power level shown on a VU METER. Although 0 VU is shown on a VU meter as the point of 100% MODULATION, it is not identical to the reference called zero level, which in fact refers to -4 dB or -4 VU on the meter.

Zero level is the reference level obtained with a 1000 Hz signal and 1 milliwatt of power in a line or circuit of 600 ohms resistance (a 600-ohm line). The corresponding voltage level is 0.773 volts. This level is sometimes called 0 dbm. Other levels may be described in reference to it; for instance, 0 VU is +4 dbm and represents a voltage level of 1.228 volts.

Compare: DECIBEL, THRESHOLD OF HEARING.

http://www2.sfu.ca/sonic-studio/handbook/Zero_Level_VU.html

other good articles on proper Vu metering techniques can be found at:

http://www.benchmarkmedia.com/meters/default.asp

and

http://www.dorrough.com/dorrough/about_us/about_vision.html

(I once got a trouble ticket saying that the "View Meter" was boken on the audio mixer)

 

[Keld]

some ideas:
http://sound.westhost.com/project60.htm
http://sound.westhost.com/project55.htm

 

[Da5id4Vz]

Post #5

The ESP articles are also very good.

The Sifam AL29B was an excellent and affordable meter movement supplied with a very readable scale (around $30). I think that Selco electronics stooped importing them to the US around a year ago and don’t know if any one else has picked up the product line.

http://www.sifam.com/vuppm.lasso

http://www.selcoproducts.com/default.asp