+4/-10 Question

[Speedy VonTrapp]

I have a thread in the Cakewalk section, thinking that my main issue was going to be concerning my software. It's come up, however, that there might be more of an issue with the way that the hardware is configured.

Here is a link to that thread.

http://www.homerecording.com/bbs/sho...d.php?t=177790

I'd like to understand the +4/-10 thing, and what is appropriate for what gear, etc. I realize that the gear that you are connecting should match, but how do I know which setting to use? I'm a bit confused in general as far as what the difference between the 2 settings are. If I could understand the nature of what is going on, I'd be able to make a more educated decision about what to use.

My gear list is in the thread above, also.

Thanks to anybody that takes the time to help teach me.

-Speedy

[bennychico11]

I'll take a stab

take a look here:
http://homerecording.com/bbs/showthr...highlight=4dBu
and do some more searches for other threads

to clarify what you're talking about, you need to add the dB units after the number.....+4dBu and -10dBV

+4dBu is an old standard that references .775V but still is used by professionals today
A new standard was created for consumers using 1V as a reference instead...it became known as -10dBV.

So when you apply .775V to a +4dBu unit, the meters should read 0
On consumer gear (operating at -10dBV), if you apply 1V if should read 0


others here will explain more in detail for you soon, i'm sure

[DonF]

Originally Posted by bennychico11

So when you apply .775V to a +4dBu unit, the meters should read 0
On consumer gear (operating at -10dBV), if you apply 1V if should read 0

Close, but not quite. Don't forget the figure in front of the unit. 0dBu is 0.775V (into a 600 ohm load), so +4dBu is (IIRC) 1.23V. Similarly, 0dBV is 1V, so -10dBV is 0.316V.

How to determine which level to use, if you have a choice? Look at the specs for the equipment you're interconnecting. They should tell you what signal levels the equipment expects/produces.

Don

[bennychico11]

Originally Posted by DonF

Close, but not quite. Don't forget the figure in front of the unit. 0dBu is 0.775V (into a 600 ohm load), so +4dBu is (IIRC) 1.23V. Similarly, 0dBV is 1V, so -10dBV is 0.316V.

ah, you're right. i knew I mixed something up.

+4dBu = 20 log ( 1.23V / 0.775V )
-10dBV = 20 log ( 0.316V / 1V )

and 20 log ( 1.23V / 0.316V ) = 11.79dB