levels , -00 , +15 ........????

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Spider

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hi all , just wondering about this .... is there any standard for these settings.. also , what exactly do they represent?? On a mixer for example , the gain might say something like +4 , -10u , ..... and so on... could someone explain these a little better . Do they represent db 's..?
If i was to set the gain a +4 , should this corespond to the LED's ?? any help appreciated ...
cheers all
spider
 
Spider, the gain, or trim, is measured in decibels, as far as I know. All that's really important about the gain is that it controls the sensitivity of the input signal. There isn't a standard, but what you want is for it to be high enough to get a clear signal without distortion and noise. And you're doing with the volume at about 70 or 75%.
After you get the right signal, adjust your volume. The level doesn't have to correspond with the LED's. Hope that helps.
 
Heres the deal!

The dB scale is a relative scale. I e one dB (decibel) does not represent anything specific, just a comparative increase och decrease relative something else. One bel is a difference of ten times in sound intensity. One bel is ten decibels, which means that one decibel is equal to an increase or decrease in sound intensity of about 25%.

So the VU meter or the led staples on your equipment shows you the level in dB relative to the standard level for your piece of equipment, where 0 dB is the standard. So what is the standard level of your equipment? Well, this is where the -10/+4dB pop up. Much pro equipment use a +4dB standard level, and most amateur use a -10dB level.
But, a clever person would now object, the standard level is a relative measure to! Is there no fixed reference anywhere? Yes there is, the fixed reference is 1V = 0dB. But don't mix that 0dB up with the 0dB on your VU meter. Your VU meter usually is 10dB lower. And don't mix that 0dB with the dB measure people talk about when they say that a jet plane is 130dB. That when measuring sounds, not electrical signals, and there 0dB is the threshold of hearing...

Yes, it's kinda confusing...
 
Hold on here. Balanced lines use +4dBm as a nominal level and unbalanced -10dBV, am I correct? Converting the two to voltage levels would give you 1.23 volts and 0.316 volts. In other words, the balanced output equipment, when reading 0 VU on it's meters, is producing 1.23 volts at its output. The unbalanced output machine, with 0 VU on its meter, is producing 0.316 volts. A diff of bout 11.8 dBs or thereabouts.
 
foo said:
Huh?
Click to expand...
Yes?

camus said:
Hold on here. Balanced lines use +4dBm as a nominal level and unbalanced -10dBV, am I correct? Converting the two to voltage levels would give you 1.23 volts and 0.316 volts. In other words, the balanced output equipment, when reading 0 VU on it's meters, is producing 1.23 volts at its output. The unbalanced output machine, with 0 VU on its meter, is producing 0.316 volts. A diff of bout 11.8 dBs or thereabouts.
Click to expand...
Yup. The reason that it's 11.8dB and not 14dB is because the +4dB equipment isn't really +4dB. It has a nominal level that corresponds to +4dB over 1mW of energy when dissipated into a 600 ohm resistor, which is something like to +2dB over 1V ( Probably is 1.8dB, I can't be botheret to check it exactly). The -10dB standard is -10dB below 1V though.
Yes, it gets curiouser and curiouser. :)
 
hey thanks for that all , really helped but still leaves a few questions... Like how do i tell the what level my gear takes ... im using the behringer 2642A desk , dbx compressors , powerplay pro(behringer headphone amp) ...Would these be +4 ?? Anyway cheers everyone for that , helped heaps..
spider
 
I think the general rule to follow is that balanced (TSR, XLR) connections are rated at +4dBm and unbalanced (TS) at -10dBV. How the signals are levelled out when you cross patch between bal/unbal I'm not too sure though! Perhaps one of the more senior members here can help?
 
Re: Huh?

I'm not questioning the accuaracy of your post, I just didn't understand it.

Take it to it's simplest form - what should I do when faced with +/- X db?

How do the db differences affect my recordings?
Thanks,

foo
 
foo said:
Re: Huh?
Take it to it's simplest form - what should I do when faced with +/- X db?

How do the db differences affect my recordings?
Click to expand...
As far as I know the answer to both questions is: "Nothing". :)
If you put a +4dB signal into a -10dB input, or the other way around, the signal will either be too low or too high. But as long as your equipment have knobs to adjust the input or output level that isn't a problem. In some cases you may not have these knobs, and then -10 to +4dB would get a bit noisy and +4 to -10dB would cause distortion.
Most equipment that can handle +4dB today seems to be switchable between -10/+4, so it shouldn't be major a problem.
 
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