What is -10dbv an +4dbu??????

  • Thread starter Thread starter hottsauce_21
  • Start date Start date
boingoman said:
And -10 gear has gotten a lot quieter with the advent of digital technology, cutting down on noise that used to come up when patching -10 to +4.
Click to expand...

I always thought that the noise was from the +4 gear that you had to crank up to make up for the fact that that you were feeding it a signal that is almost 20db lower than it is expecting.
 
Farview said:
I always thought that the noise was from the +4 gear that you had to crank up to make up for the fact that that you were feeding it a signal that is almost 20db lower than it is expecting.
Click to expand...

Yeah, I can see that, especially not-so-good +4 gear cranked up at the inputs.
Like someone else pointed out, +4 doesn't mean pro. There is lots of shitty +4 gear out there, and lots of -10 gear that is well-built, quiet, and sounds great.
I'm pretty sure it's a combo of the two. A +4 piece of gear cranked to the max, and an inherently noisy source like home-recorded cassettes or crappy -10 gear.
I also wonder if there are some kind of impedance issues involved. My analysis is just based on what I've encountered, for the most part. For instance, my home CD player will easily interface with my +4 gear with a minimum of input..mmm..upping, as it were. :)
 
boingoman said:
I also wonder if there are some kind of impedance issues involved. My analysis is just based on what I've encountered, for the most part. For instance, my home CD player will easily interface with my +4 gear with a minimum of input..mmm..upping, as it were. :)
Click to expand...

If you are playing recent CDs in your player, the reason for the minimal 'upping' is that everything is compressed to death. The analog equivelent for full scale digital is (generally) +12. That is what is pushing the input of the next thing in the chain.

This whole thread is about gain staging. if everything is set at the same standard, you won't have any problems that are not user error.
 
So if I have SOME gear that can be set for +4 but also a lot of gear that is only -10, should I just set everything for -10 to get consistency when connecting gear together (I use all external hardware, no computer usage)?
 
In a word...

Yes...

Trying to drive a device looking for a +4 input from a -10 output brings the noise floor right up to your arm pits...

Low signals levels are responsible for noise... high levels are responsible for distortion (and clipping)... proper gain staging is a compromise between the two....
 
This is from our recent newsletter where we talked about this:


A zero reading on a device's meter indicates a specific AC voltage within a unit, calibrated to one of two audio standards. The professional audio standard is +4 dBu. An analog device calibrated to +4dBu references its
0 dB meter reading to an input/output voltage of 1.23 VRMS, and the connection is generally balanced.

Stereo or semi-pro equipment, which includes a good deal of home-recording gear, is referenced to the consumer-level standard known as -10 dBV. In this situation, a 0 dB meter reading indicates an input/ output voltage of 0.316 VRMS, and the connection is typically unbalanced. In this comparison dBu and dBv can be considered as equivalent, but there is 14dB of gain level difference between the two operation level standards.

When interfacing both kinds of equipment, there is an 11.8 dB voltage discrepancy between -10 dBV and +4 dBu reference levels. If the devices in your studio are the same type (-10 dBV or +4 dBu) and each one is
properly adjusted and performing no gain changes, a 0 dB test tone to the first unit's input should a 0 dB level at the last unit.

I hope this helps....
 
See this is what bothers me.

When I set my soundcard to +4, all of the levels on my pre-amps work right. 0 syncs up with on the hardware and software, but I have to jack the gain which makes tons of noise.

If I set it to -10, the meters arent right, but I barely have to touch the gain and I can get a clear recording.

Is there something I'm missing, or am I just retarded?
 
alanhyatt said:
In this comparison dBu and dBv can be considered as equivalent, but there is 14dB of gain level difference between the two operation level standards.

When interfacing both kinds of equipment, there is an 11.8 dB voltage discrepancy between -10 dBV and +4 dBu reference levels.
Click to expand...
Alan,

I don't understand those 2 statements... the difference in level between a -10dBV and +4dBu signal is 11.82dB.... period.

The comment of 14dB gain level difference makes no sense because they are 2 different ratios for 2 different frames of reference -- it's apples and oranges.

:confused:
 
Last edited:
demensia said:
If I set it to -10, the meters arent right, but I barely have to touch the gain and I can get a clear recording.

Is there something I'm missing, or am I just retarded?
Click to expand...

Yes, that's because a signal that is 11.8dB weaker will give you the same dBFS reading in your computer.

Before you assume that's a free lunch, check the noise floor specs (or dynamic range) on your card at the two different settings.
 
Blue Bear Sound said:
Alan,

I don't understand those 2 statements... the difference in level between a -10dBV and +4dBu signal is 11.82dB.... period.

The comment of 14dB gain level difference makes no sense because they are 2 different ratios for 2 different frames of reference -- it's apples and oranges.

:confused:
Click to expand...
Is that 11.82db dbu or dbv? I used to know all this. It is way too early in the morning to be dredging all this up.

My brain hurts.
 
It's dB... the 11.8 is simply the difference in signal level between the two gain structures.

If you send 2 of the same signals to a mixer, one via a +4dBu signal path and the other via -10dBV, looking at the meters you will see an almost 12dB difference in signal level between the two of them.
 
You must log in or register to reply here.
Back
Top