International dBFS Levels:
On a technical note, 0dBm (an old telephone and early broadcast system of reference) is
the voltage required to dissipate 1mW into 600 ohms = 0.775v ac. 0dBu (also 0.775v ac)
just means that the impedance of the circuit is not specified. These, set in granite actual
voltage levels, rather go out of the window when referred to dBFS figures associated
with digital converters! (dBFS =
d
eci
B
els
R
elative to
F
ull
S
cale... i.e the clipping point
of the system)
There is no single standard for setting where the 0dBFS point is...!!!
For example...
1. EBU R68 is used in most European countries, spec18 dBu at 0 dBFS
2. In Europe, the EBU recommend that -18 dBFS equates to the Alignment Level
3. European & UK calibration for Post & Film is −18 dBFS = 0 VU
4. UK broadcasters, Alignment Level is taken as 0 dBu (PPM4 or -4VU)
5. US installations use +24 dBu for 0 dBFS
6. The American SMPTE standard defines -20 dBFS as the Alignment Level
7. In Japan, France and some other countries, converters may be calibrated for +22
dBu at 0 dBFS.
8. BBC spec: −18 dBFS = PPM "4" = 0 dBu
9. German ARD & studio PPM +6 dBu = −10 (−9) dBFS. +16 (+15)dBu = 0 dBFS.
No VU.
10.Belgium VRT: 0dB (VRT Ref.) = +6dBu ; -9dBFS = 0dB (VRT Ref.) ; 0dBFS =
+15dBu.
0VU on the Aurora Sidecar VU meters is +4dBu (1.228v ac) and normally -18dBFS on
the meters of the digital converters.
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