Rohith,
I haven't seen a reply to this, so here goes.
[Actually, this is an ANALOG concept. As such it doesn't really belong on a
"DSP" list but any way...]
Decibels (dB) are *relative*, comparing one measurement to another. The suffixes
added to the dB, such as dBm, dBu and dBV, are, in this case, meant to add a
reference, making the measurement relative to a standard other than decibels.
In the case of dBm, it's 1 milliwatt of power on a circuit of 600 Ohms
impedance to equal 0 dBm.
This type of measurement was relevant when the systems in use were designed to
transfer power over a circuit of specific impedance, such as was the common case
when the state-of-the-art was tube equipment and transformers.
Electronic audio design has changed over the years so that almost all audio
transmission from one place to another is generated by a source of very low
impedance, sent to a load of relatively high impedance, such that *power* is no
longer an important part of the equation.
Enter "dBu." The "dBu" spec works identically to dBm when the source/load
impedance meets the old dBm spec, but since its reference is to a specfic
*voltage* rather than power, it also works when the impedance is unspecified.
That voltage, by the way, is 0.775 RMS for 0 dBu.
In the case of dBV, it's similar to dBu, but relative to one volt, to equal
0 dBV.
David Reaves
Sun Jun 28, 2009 8:59 am ((PDT)) "Rohith MP" r...@lntemsys.com mp_rohith
wrote:
Hello,
Is there any relation between dbu and db/dbV.
I have IO box with option of Hi-Gain, +4dBu gain and -10dBV gain.
Basically these are hardware switches present in the IO box.
What does +4dbU recording actually mean?
What does -10dBV recording actually mean?
While performing recording of a file, I found that @ -10dBV recording, the
recorded file used to get clipped, what might be the reason?
Is -10dBV recording has more gain when compared to +4dBU gain?
Thanks in advance
Rohith M P