Low Signal Levels into Pro Tools?

[SimonInAustralia]

We have a Venue Profile MixRack system.

The level into Pro Tools through the HDx cards seems very low.

Is this normal?

I think it says in the manual that you can get more level into Pro Tools by using Direct Outs.

How do I use Direct Outs to get more level into Pro Tools?

Can I still have 48 channels going into Pro Tools from Direct Outs?

Is the gain being added by the Direct Outs a digital gain increase, and much the same as bringing the gain up digitally once in Pro Tools?

If so, is there anyway to get a hotter analogue signal for Pro Tools?

How are you running your gain staging to get good levels into Pro Tools, or are you not worrying about low levels?


Thanks,
Simon
Canberra
AUSTRALIA

[digidesigner]

The level you see in PT is the actual level, if you change gain with direct input level knob then it's the same as adding gain in PT. Just run your inputs hotter and if you don't like mixing with faders down (like I do) assign VCA's and pull them down as much as needed to keep your mix faders @ around 0

[Sheldon Radford]

Hi Simon,

Check out this article for more info on recording level and Pro Tools.

How do I use Direct Outs to get more level into Pro Tools?

Assign the channels within the Directs tab of the patchbay, then adjust the Direct Out level

Can I still have 48 channels going into Pro Tools from Direct Outs?

No, only 16 assignable channels are available within the patchbay

Is the gain being added by the Direct Outs a digital gain increase, and much the same as bringing the gain up digitally once in Pro Tools?

Yes, it's digital gain so you're correct in that there's no benefit to increasing the gain via the Direct Out versus gaining it up in Pro Tools afterwards; in fact, it's safer to add the digital gain in Pro Tools after the fact, as this decreases the chance you'll record a clipped signal.

Sheldon

[Roland Clarke]

It's worth checking that your metering on the Venue is RMS not peak, this can lead to levels looking good on the console but registering low into Pro Tools.

Regards


Roland

[SimonInAustralia]

Thanks for the replies.

I just went in and tested it with a test tone going into the MixRack.

It is already set to RMS meters, instead of peak.

It is doing something really strange, as I bring the gain up on that channel of the Profile, the level into Pro Tools is not following it the same.

It seems to hit a certain level, like -6.4dB on the Pro Tools meters, then it stops increasing as the Profile gain is increased, and then jumps up to full level in Pro Tools when the Profile meters reach +15.

Is anyone else seeing this?

Has anyone else tested the level into Pro Tools, compared to the Venue, with a test tone and winding up the Profile channel gain control?

I might have to video what is happening, and load it up to YouTube, to show you the 'problem'.

[Sheldon Radford]

Hi Simon,

The behavior described is expected. Here's the explanation...

VENUE systems use a hybrid gain approach, with a combination of analog gain (in 3 dB steps on Stage Rack, 6 dB steps on Mix Rack) and digital trim (in 0.1 dB steps). The single Gain knob on the console controls both of these parameters, and takes care of automatically switching in the appropriate amount of analog gain (in coarse steps) to ensure the best possible audio performance, while also providing the digital trim to allow for adjustments to made in finer increments.

The point at which the stage (mic) input feeds Pro Tools is immediately after the analog/digital converter, and before the digital trim control. This captures the purest signal possible, with the best signal-to-noise ratio, before any processing takes place. This also means that the level going to Pro Tools is effectively adjusted in coarse steps, as the analog gain changes (in 3 dB or 6 dB steps, as mentioned).

If finer gain control is desired, it's possible to use a Direct Output to feed the assignable outputs to Pro Tools (for a limited number of channels). Note, however, that in this case it's simply adding digital gain, and there's no advantage to adding the digital gain in the console when sending the signal to Pro Tools, versus adding digital gain after the fact in Pro Tools. In fact, it's safer to do the latter, as it's less likely that you'll capture a clipped signal.

Hope that helps explain things. There's more info on the hybrid analog/digital gain control in the HDx user guide. See the section on "Managing VENUE Settings During HDx Playback"

Sheldon

[Live Sound Audio]

Thought this is not a great answer, the lower levels has always kept us from clipping and after the recording I just select and apply an audio suite gain to all the tracks...

[digidesigner]

Sheldon, if digital gain is not added to signal going to PT does that mean the virtual souncheck levels can be as much as 5.9 db's off coming back to board from PT?

[Sheldon Radford]

When HDx is used as the input source the digital trim portion of the analog gain + digital trim control is automatically applied, making the input from Pro Tools the exact same level as the live microphone input. If it didn't do this it wouldn't be much of a Virtual Soundcheck, as the levels would be all over the place.

You can see this in action by noting the Gain controls while in HDx mode - they will often be some non-zero value, which represents the digital portion of the analog + digital gain control.

Sheldon

[SimonInAustralia]

Thanks for the detailed explanation Sheldon.

I also noticed that there is a setting for how far below 0 full scale the input clip light turns on.

It was set to 6dB below 0 full scale when the Venue shows a clip, I suppose we can raise this to maybe 3dB below 0 full scale to get a hotter signal into Pro Tools.

The teacher and students were backing off the gain when the Venue meters flashed red, which was still 6dB before 0 full scale.