Unexpected Overdub during live recording

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smallfreak
Posts: 13
Joined: Mon Oct 23, 2017 10:44 pm

Unexpected Overdub during live recording

Post by smallfreak »

Hey folks, here I am. New and fresh. :)

And I'm going to bother you with some of my problems. Since long posts do repel casual helpers, I added some structure, so you can easily skip most of it.

First of all, I want to express my deepest respect. I do recognize a truly great piece of software, if I face one. The VoiceMeeter and "Banana" are something that should be bundled with every computer doing any kind of sound. I never thought, that my plain vanilla PC might be capable of THAT. This is just GREAT!

--- lament starting here ---

Being quite new in the field of recording, I did quite some research on both equipment and software and settled with a pair of CM3 Mics, a UR242 interface and VoiceMeeter along with Reaper for the recording. However, since running a full DAW to record a live performance of our orchestra seemed to be a bit too complex, I'd thought to give "Banana" a chance to do it all alone. A lean All-in-one solution capable of multi track recording.

Unfortunately life does sometimes infer with the best intentions. I did a couple of dry runs during rehearsals to make sure I get it right when I just have a few minutes to put up the mics, start the Notebook and off it goes. I found good settings for the buffer size that provides a clean signal, no loops, a signal limiter (just in case), so it SHOULD work in the field.

Well, it did not. I'm sure I am a dullhead that made some silly mistake(s) and not even really clever software as the VoiceMeeter can save me from (probably) doing something really stupid.

As I have learned, the "recorder" starts a new file every time, the "record" button is clicked. This is not explicitly stated in the manual, but quite what I hoped it does. On the set I had the chance to reassure me of this function on the performance of a couple musicians that performed before we were in charge. Every stop and record made a fresh file, so I happily did a final "record" just before we had to enter the stage.

As soon we finished, I stopped the recording and did a short rewind to check what I got.

--- problem description starting here ---


Well, I somehow managed to record our performance ON TOP of the previous recording into the same file :o
So what the f... has gone wrong there? A hidden feature? The entire recording unusable. :cry:

I DID have a Plan-B and had a Zoom Field recorder running - just in case, but that was a VERY unpleasant surprise.

Btw. the recording would have been crap anyway, as it was infested with pops and gargling all over. Nothing of this did appear in my tests and the headphone signal on the interface was clean by its nature. Obviously Windows 10 decided to do some work intensive maintenance tasks RIGHT NOW, when it had "nothing else to do". :evil:

I have a couple of indicators that make me aware of possible clipping but really none that can detect data loss? The "solution" is, to cross fingers that the tested setting will work the next time too? I always can check the record afterwards, but often I just have only one chance.

--- question starting here ---

So would anyone please enlighten me what I might have done to accidentally produce an overdub and if there is really no way that the system could give me a hint that there are buffer errors occurring while they are occurring. Just a hint would have helped me to be aware of the problem before it got catastrophic.

Thanks for listening,
smallfreak
Vincent Burel
Site Admin
Posts: 2008
Joined: Sun Jan 17, 2010 12:01 pm

Re: Unexpected Overdub during live recording

Post by Vincent Burel »

Thanks for your message, and sorry for this problem.
this i snormally not possible (our record process cannot overdub and normally cannot use an already existing file, since the name is changing with date and hours)...

first of all i need to know your Voicemeeter Version.

BTW: for multitrack recording, you may try MT32Splite.
smallfreak
Posts: 13
Joined: Mon Oct 23, 2017 10:44 pm

Re: Unexpected Overdub during live recording

Post by smallfreak »

In my paranoia I even muted every input other then the two mics, just to ensure that I would not accidentally record any internal sound or other source that might want to get heared. But even then this should got recorded on separate tracks, wouldn't it?
it is maybe not very clearly explained in the user manual page 21,22:
https://www.vb-audio.com/Voicemeeter/Vo ... Manual.pdf

but when recording PRE-FADER INPUT: all these armed inputs are mixed together before being recorded in the file.

PRE-FADER INPUTS
This option allows recording one or all inputs in stereo, independently from the fader gain (and
mute and solo states).


to record in multitrack, you may record a BUS (POST FADER BUS) in COMPOSITE MODE (page 17).
the COMPOSITE mode will allow you to assign input channels to BUS channels, so to recorded file (up to 8 channels in a file).

POST FADER OUTPUTS
This options is made to record the outputs of a BUS (from 2 to 8 channel) possible with
Composite options.
smallfreak
Posts: 13
Joined: Mon Oct 23, 2017 10:44 pm

Re: Unexpected Overdub during live recording

Post by smallfreak »

PRE-FADER INPUTS
This option allows recording one or all inputs in stereo, independently from the fader gain (and
mute and solo states).
So then this does not imply this would record EACH input in SEPARATE stereo and I have to triple check to disable all channels that do not definitely carry the intended signal. I did not need this, but I definitely did understand it that way.

This way it could have happened that the first recording started to play in the background anyhow and the output of this would certainly be mapped to one of the virtual inputs where it gets mixed together with the live signal, even if I "muted" that channel. I just wouldn't notice that. My headphones would not get the looped signal because I muted it on the bus. Bang - shot into the foot.

This could explain the clicks and pops due to lost data too. In this scenario the PC has to process four channels of audio instead of two AND i have a player running in the background competing for CPU and memory. This could easily more than triple the intended load.

While I'm really quite sure I did not intentionally start a playback and I cannot remember that I had to close one at any time, it still may happen that a careless click can trigger an unobtrusive audio player.

At least I now have a working theory.

And by chance have got a good recording due to a backup-backup plan B+ :roll:

So then there is still the big question
Why is it not possible to get a live "data lost" hint when the buffer gets overrun or runs dry?
That's quite standard at the comparable problem when writing data to CD.

It's quite bad I can only find out afterwards, when all is in vain and nobody can do anything against it anymore.

A "volume bar" showing the buffer content would be great, a red "buffer clipping" LED the next best one. Crossing fingers and true faith may help any now and then but this is not very reliable.
smallfreak
Posts: 13
Joined: Mon Oct 23, 2017 10:44 pm

Re: Unexpected Overdub during live recording

Post by smallfreak »

Btw. What happened to my primary answer (the one where the quote in post 3 was taken) and why do I seem to answer to myself?
Do I suffer a split personality?
:?
Vincent Burel
Site Admin
Posts: 2008
Joined: Sun Jan 17, 2010 12:01 pm

Re: Unexpected Overdub during live recording

Post by Vincent Burel »

smallfreak wrote:Btw. What happened to my primary answer (the one where the quote in post 3 was taken) and why do I seem to answer to myself?
Do I suffer a split personality?
:?
oups, sorry for this, i certainely made a EDIT instead of REPLY.

The fact is that Voicemeeter Recorder is a simple single file recorder and is configured by default to record all Voicemeeter Sources (pre-fader) to let you record a conf call with Skype or other for example.

USER MANUAL USE CASE 3 explains how to make a multi-channel recording, and assign each sources to a different channel with the COMPOSITE MODE (with Voicemeeter Standard we use REAPER to record 8 tracks - But µBanana recorder can also record this 8 tracks as 8 channels of the file):
https://www.vb-audio.com/Voicemeeter/Vo ... Manual.pdf

i'm going to add some information about this in the banana user manual...
smallfreak
Posts: 13
Joined: Mon Oct 23, 2017 10:44 pm

Re: Unexpected Overdub during live recording

Post by smallfreak »

Vincent Burel wrote:i'm going to add some information about this in the banana user manual...
Thanks for clarifying. This is certainly because VoiceMeeter was intended to solve a certain problem recording external and internal sound sources together.

I'm coming from a quite different direction and thought the default to "record all inputs pre-fader" was the idea to offer some kind of "raw audio recording", something like shooting RAW images on a modern digital camera. No matter how i fiddle the knobs, I always have the chance to re-mix it later from the recorded, unmodified, original sources. It may help if you explicitly mention some "obvious" facts in the docs too.

At the moment I cannot think of a case where recording "all inputs pre-fader" could be a benefit over recording the mixed signal as (by definition) you virtually have no control over the the signals. It's more like some forensic evidence that "something" was received at the input and "nothing is lost".

So for my intention it certainly would be much preferable to record post-faders so at least I'm in control how much of what gets mangled together or I skip VoiceMeeter altogether and directly connect the interface to a (lightweight) DAW or maybe MT32 as you mentioned. I tried this, but currently I'm still a little lost in the settings. It will take some time to get a feeling for this tool. I'm definitely no audio engineer. :(
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