VU meter - incorrect, non-standard values

2016-12-05 21:24:55

VU Meter in Foobar is not calibrated correctly.
It sholud be calibrated RMS+3dB according to IEC 61606:1997 standard

https://www.gearslutz.com/board/4153777-post2.html - Bob Katz explanation

http://www.bluecataudio.com//Vault/Products/Product_DPeakMeterPro/manual.pdf - page 6

Re: VU meter - incorrect, non-standard values

Reply #1 – 2016-12-06 07:05:16

That's the AES standard for measuring RMS (not VU), and it's not the only standard, so it's not "wrong". FB2Ks implementation uses an earlier mathematical standard, and it's not hard to just add 3dB. Good digital meters usually have a setting called "AES" or "+3", so you can choose which to use.

I can highly recommend the Klanghlem VUMT plugin, it's definitely the best digital VU meter I've seen, and set up right is almost exact with my hardware Sifam VUs.

http://klanghelm.com/contents/products/VUMT/VUMT.php

Re: VU meter - incorrect, non-standard values

Reply #2 – 2016-12-06 13:35:57

I've already got a very good measuring tools in my DAW.

It is impossible to use VST (VU/RMS/Peak) meter in foobar - there is no correlation between audio and meter readout. Everything is shifted because of the VST chain delay and buffer length (foobar output preferences.)

In digital era there should be a real standard (RMS+3) meter in foobar. The actual VU meter is completelly useless.

Re: VU meter - incorrect, non-standard values

Reply #3 – 2016-12-06 16:52:39

Glad you've found some good measuring tools that work for you, why don't you just use those to look at the VU reading? I agree that visualisation VST plugins in FB2K often look wrong or laggy, but some seem to work OK. I guess FB2K is a media player first and foremost, and modern metering standards and visualisations are not at the top of the devs' to do list. I assume people who need such tools (such as ourselves) already have them as part of their pro audio tool kit. I certainly don't miss having an AES compatible VU meter in Foobar...

I personally don't find actual VU meters "completely useless" at all. If they were "completely useless", they probably wouldn't have been in continuous use since 1942 now, would they? Nothing like the real thing, which when learned properly give a helluva lot of information about the sound source. I love my Sifam/Crookwood VU.

Original paper on VU spec from 1940: http://www.aes.org/aeshc/pdf/chinn_a-new-svi.pdf

Re: VU meter - incorrect, non-standard values

Reply #4 – 2023-09-11 11:03:42

If anyone is interested in calibrating the VU Meter, i found a solution.
Go to: preferences - playback - preamp
There you find 2 faders.
I adjusted the one without RG info to -9,3 dB
Now it's not crossing the 0dB mark, volume goes down, but since neither the windows volume, nor the
foobar volume control do affect the VU meter (which is normal),
you can simply compensate for the playback volume reduction by turning up one of those.
This setting may or may not be adequate for your system, also i did not perfectly adjust it yet.
Maybe i later on will try with some test signal that is exactly 0 dB, to calibrate it perfectly.

cheerio