Subject:IN THE RED...Headroom for Acid 3.0pro?

Posted by: MattX

Date:5/24/2002 8:17:50 PM

what is the headroom for Acid 3.0?
we are able to push it all the way into the red and it doesn't distort, why?

what is the headroom for this program,
how far can we push it into the red?

happy holidays acidheads!

Subject:RE: IN THE RED...Headroom for Acid 3.0pro?

Reply by: Chienworks

Date:5/25/2002 9:41:08 AM

There is ZERO headroom in digital recording. If you hit +0.0dB, you're hitting distortion and the peaks will be clipped.

Subject:RE: IN THE RED...Headroom for Acid 3.0pro?

Reply by: bgc

Date:5/25/2002 11:55:37 PM

Acid's meters start to turn red around -3dB I think. Don't look at colors, look at the numbers. Anything over 0 dB (positive numbers) are clipped and will introduce distortion.
bgc

Subject:RE: IN THE RED...Headroom for Acid 3.0pro?

Reply by: TeeCee

Date:5/28/2002 11:59:32 AM

Hopefully you will get something official from a Sonic Foundry rep (or maybe it's in a FAQ or already covered). The meter reading is not necessarily the same as the level of the audio output or rendered. That would be a programming decision. Also, if you are using multiple buses each going directly to your sound card's outputs, you could be overloading the card even though the buses are not clipping individually.

What I have noticed with use of Acid and Vegas is that the mixing seems to have varied with the different versions. If you want to see how Acid's meters correspond to file levels, set your project to clip by about 2dB, render to a wave file, open it in Sound Forge, open Normalize (but do not Normalize), and click on the scan levels button. I know that there is a Statistics feature in Sound Forge, but the Normalize|Scan Levels function seems to give more accurate results for peak levels. Right there next to the button, you will see what the peak level is for your rendered wave. Go back to Acid, set your levels to give you a peak of approximately -2dB, render to a wave file, and repeat the Sound Forge process. Between these two scans, you should be able to see how Acid's meter corresponds to actually file levels. If you are using multiple buses sending directly to your sound card, this process will probably not be effective. You probably will not be able to hear brief digital audio clips so don't assume it isn't happening just because you can't hear it.

TeeCee

Subject:RE: IN THE RED...Headroom for Acid 3.0pro?

Reply by: pwppch

Date:5/29/2002 4:59:24 PM

Actually in ACID 3 they meters to match what you are rendering IFF you route only your master bus to hardware.

If you route any bus other than the master to hardware there is no way we can "mix" correctly on a render since we don't know what the external gain stages are on the external hardware.

Even with the Master bus, what you hear and what you render can be different since again, we don't know or have any control over the external gain stages.

In general, what you see on your master bus meters will match with what you render.

Peter

Subject:RE: IN THE RED...Headroom for Acid 3.0pro?

Reply by: MattX

Date:5/29/2002 11:09:13 PM

MANY THANKS TO ALL WHO HAVE ENRICHED MY KNOWLEDGE!

Subject:RE: IN THE RED...Headroom for Acid 3.0pro?

Reply by: TeeCee

Date:5/30/2002 11:46:43 PM

Peter,
You filled me in before, but I'm not following you now. If I have Master and Bus A both going to Hardware. When I mix down, are these summed, summed with padding on each, or "averaged"? I guess averaged would be summed with a 3dB pad on each. And does Vegas work the same way?

Thanks,
TeeCee

Subject:RE: IN THE RED...Headroom for Acid 3.0pro?

Reply by: pwppch

Date:6/3/2002 9:47:04 PM

All sub buses are merely rerouted to the master bus temporarily. So what ever gain settings are on the Sub bus are used to mix with the master bus.

We tried in the past for Vegas to do the -6db for two, -3db for four, etc, etc and this just produced garbage. The point is that we have no control over the external routings so what ever happens in the end is a best guess.

This is why we added the master bus. You mix to the master and render to the master.

If you are routing sub buses to external hardware, then I suggest you record the output of the external mixer stages.

You will never achieve the results of "What you hear is what you render" when routing more than the master bus to external hardware.

Peter

Subject:RE: IN THE RED...Headroom for Acid 3.0pro?

Reply by: TeeCee

Date:6/5/2002 12:07:14 AM

Peter:
Thanks for the reply. I believe I have been routing all channels to subs and all subs through the Master lately. This is very easy to work with and the results have been audio files with rather predictable peak levels. I'm also glad to hear that the subs are not being averaged.

I'm glad this came up. It brought up an issue I was having with the FX sends being post volume fader. So I decided to look in the help file where it explained that I could right click and choose pre-volume. I'm sure this is in the manual somewhere as well, but I don't have a habit of reading manuals. I wonder what else I haven't discovered.

TeeCee

Subject:RE: IN THE RED...Headroom for Acid 3.0pro?

Reply by: pwppch

Date:6/6/2002 12:28:31 PM

Actually I don't believe it is discussed in the manual/help. It is a bit of a problem, and not easy to explain as I get a lot of mail on this particular issue. The notion that we have no control over the external gain stages when routing to external hardware is sometimes lost on users.

There are basically two modes to work in :
- Virtual mixer via the Master bus with sub busses
- Tape recorder mode where all buses are routed to external hardware

For the later case, I always recommend creating as many buses as you need and avoid the master bus so as not to confuse issues. That is, use Bus A, B, C, etc for all track routes and leave the master unassigned. When you do things this way, the buses become peers to each other.

The only downside to this approach is that you can't have global or mastering FX. However, since the tool is being used like a tape recorder, the mastering is being done externally as would be expected.

Peter