Level change when switching from Stage Rack to HDx Pro Tools

[Scott Fahy]

Is there a reason why the level changes drastically when we switch from the stage racks to the HDx cards. Used the same snapshot for a song and all I did was just change the input source. Yes I understand that with the room empty things will seem louder but this was measured on an SPL meter and we went from 90 to 94db c weighted fast to 96 - 100 db. I know this has been discussed before wanted to get back up to speed on the why.

[Sheldon Radford]

Hi Scott,

If the same show file was used to record the tracks in the first place then there will be no apparent level difference. However, if the tracks were recorded some time ago, and are being used with a new or updated show file then there could be a level difference. This is because the gains used for the original recording don't relate directly to the gains in the show file. (I.e., the tracks were recorded at one gain setting, which is different from what the channels are currently set to).

Other reasons for a level difference include VCA or Mains fader level differences.

Sheldon

[Scott Fahy]

Sheldon,
The file was what was recorded last Sunday so that rules that out, and all of the setting on the console, VCA's, Groups and PQ's (which drive the mains) were exactly the same. I loaded the file from last Sunday recalled the first snapshot of the music then switched to the HDx source and started Pro Tools. Any other thoughts?

[Kenmillerjr]

Sheldon-

Would there be a difference by selecting "Input Mode" or "Virtual Soundcheck?" This is a question I received today, and thought it may relate to the above question.

[Sheldon Radford]

There could be a small level difference. Virtual Soundcheck mode takes the current mic pre settings into account, and adds up to 3 dB of digital gain in order to ensure the recorded signal (which is captured before the digital trim control) exactly matches the live source. For input mode, all gains are set to nominal 0 dB.

Sheldon

[Scott Fahy]

We used the INPUT mode, so if during the original tracking to PT a gain was set to - 10 does this increase the gain to 0?. (We are using the Digital IO cards so there is no analog gain in the picture).

[Sheldon Radford]

Ah yes - that would do it.

Here's what to do:
1. Load the file in Stage mode. Your gains should all be digital trims (-20 to +18 dB).
2. Save a snapshot to capture these gain settings. For all channels, scope only the PRE parameter
3. Switch to INPUT mode. All gains may go to 0 dB.
4. Recall the snapshot stored in step 2. This should then reset the gains correctly.

Sheldon

[Scott Fahy]

Awesome, I'll give it try tomorrow when I get back to work and let you know. Thanks Sheldon.