Controlling the REC level!

Classicalmusic · 10-12-2008, 01:55 PM

Hi to everybody!

I have just installed Reaper on a system where it is intended to be used with an external (USB) sound card Fast Track Ultra (by M-Audio). It is a 4-channel device, I use it connected to 4 microphones for classical music sound takes.

I need to record the 4 microphones, one track for each mic, and to save the recording as 4 separate WAV files for later editing.

Basically, I could get Reaper to record/save in the way I want quite easily,
but there is an oddity. I cannot control the RECORDING LEVEL with ANY of the software sliders in Reaper (and I tried ALL of them...) nor in the sound card manager utility program. The VU-meters don't change, and the recorded signal neither. The only way to control the recording level is via the hardware potentiometers on the control panel of the audio interface.

The obvious problem with this is that I cannot memorize and repeat a given level setting for a given environment! I could save a software slider's position, but could NOT maintain or reposition 4 little knobs on the same identical setting.

The other indication of something wrong (I can't say whether the two things are somehow connected) is that, on the button on the upper-right corner, it's reported that my project is at 44.1 kHz 32 BIT!!! It is intended to be at 16 bit, but cannot change it in any way. I say again, I don't know if these two issues are related.

ASIO driver is enabled, and the audio interface is correctly installed and fully recognized and controlled by the management utility.

Do you have any idea???...

Thank you very much to all of you!

LOSER · 10-12-2008, 02:07 PM

It's normal that you can only change the recording level at the hardware. Because it has to happen BEFORE the quantization that happens in the ADC.

The top right corner displays the i/o format of the hardware and for ASIO the bit-depth the driver communicates is always 32bit.

Classicalmusic · 10-12-2008, 02:23 PM

Quote:

Originally Posted by LOSER

It's normal that you can only change the recording level at the hardware. Because it has to happen BEFORE the quantization that happens in the ADC.

Wait a minute... question from a dummy: but then, what are the software sliders for??? (both in Reaper and in the card manager program)

You are saying that there is no way to memorize and REPEAT in a DEPENDABLE WAY a given REC level setting??? So, I have an expensive matched pair of microphones, factory selected to within <0.5 dB each other, and at the end of the story, all I can do is to manually set two potentiometers to, let's say, 3-4 dB each other??? Noooooo.... can't be....

Tedwood · 10-12-2008, 02:53 PM

The software sliders are for mixing after recording, you do want to adjust the input at the hardware device, just as you would any other device such as a tape recorder, so you have the optimal signal level at input.

Just set all four the same every time - no need to remember anything

livedead13 · 10-12-2008, 04:55 PM

mic preamps are analog. it's necessary to set their levels before the digital conversion. setting levels is part of recording audio. there is no way around it. you can just set it and forget it, but unless your recording environment is constant and your instruments and mics never change position, it won't do you much good.

Classicalmusic · 10-13-2008, 12:33 AM

Wait a second... this is NOT clear.

So, if all the sliders in Reaper are for after-recording changes, what about the sliders in the audio card manager? They don't change the levels as well! Before this 4-channel audio interface, I used a smaller 2-channel one, with MIC and LINE stereo inputs: the sliders in its manager program DID CONTROL the recording level! I could memorize the settings and recall them later with absolute precision. So what's wrong now?...

Quote:

you can just set it and forget it, but unless your recording environment is constant and your instruments and mics never change position, it won't do you much good.

That's the point! The recording equipment is NOT installed in a studio, but taken around in cathedrals and concert halls. It's not possible NOT to move the level potentiometers after recording in a given location, because there will be other sessions in other locations. But, even if the equipment were permanently installed somewhere, the rotary potentiometers don't allow, for example, to simply set the sensitivity of two channels at the same value, because of the lack of a precision reference: only software control (sliders) has the necessary resolution.

I feel lost...

Art Evans · 10-13-2008, 12:58 AM

Hi Classicalmusic, another classical person is here to make you feel at home! Though I'm afraid that regardless of the music genre, the rules remain the same...

Gamer's soundcards like most of the Creative ones have controls in the soundcard's control panel to make you think that you are varying the input levels, though I rather suspect that all they are doing is monkeying with the levels in the digital domain after analog to digital conversion.

Proper soundcards or interfaces have either no level control at all, or if they include preamps, then the trim on the preamp controls input level. You have to control the level at that point else you could be hopelessly overloading the preamp before the analog to digital conversion.

Reaper, and all recording software, operates only on the digital information passed to it from the soundcard or interface. So it can't affect the recording level, as that has already been set by the soundcard or interface. It can affect the playback level by manipulating the digits, and in fact it's possible to record that manipulation during recording by right clicking on the record enable button on the track and selecting "Record output". But that's a very unwise thing to do - you are permanently altering the digital stream coming from the soundcard, whereas if you do that during playback, you can choose the level with the benefit of hindsight.

If the level from the soundcard is too high, it's getting distorted in the soundcard. There's no point in turning it down in Reaper as it's too late in the chain. You simply have to set levels properly at the soundcard or interface.

I'm afraid we all have to contend with setting knobs accurately for level. Unless, that is, you have a preamp with digital controls and a display to match. (In that scenario, the knobs on the interface send a digital value to the preamp, which modifies its gain accordingly).

As for matched mics - don't worry too much. If you can't hear the level difference between them once they have gone through the preamp, nobody else can hear it. If it does sound lopsided, well, alter the preamp levels appropriately. Or do the same with Reaper in postproduction.

I get the feeling you are fairly new to all this. Let me give you a tip from someone who has been at it for 40 years! In reality there is only one level - ok, slight exaggeration, but think of it like this. If you record a symphony orchestra, your mics will normally be quite high and some way back. The sound level reaching them will be appropriately reduced. If you are recording a guitar, you'll be a couple of feet away at most, and the sound level at the mic will therefore be effectively raised. On my stereo preamp I made a red mark years back that I line the knob up with. Nine times out of ten, regardless of what I'm recording (with my normal stereo pair) then that's the ballpark level. You'll quickly get to know the level that works best with your equipment - mark it and forget it. Then you'll be able to impress people no end by not needing level testing and so forth.

Personally I now use an Edirol R-44 recorder rather than hump round a ton of stuff and a laptop that freezes for 10 seconds once a day (and of course that ten second freeze is bound to happen in mid performance...). And its preamp controls are in 6dB notched steps, so repeatability is no problem. Then I dump the memory card contents into Reaper back at base for post production.

Hope all that helps... good luck!

Tedwood · 10-13-2008, 01:12 AM

Nothing needs to adjusted on your computer at all, the only variable is the strength of the analog signal coming from your microphone, so that's what needs to be trimmed, just bring the level up as high as you can before clipping occurs

I set my input sliders on my soundcard mixer to 0.00 db and only looked a couple of times to check I am not overloading at the PC input.

Try with a normal track with no FX or recieves etc, set to 0.00 dB, any overload shows in Reaper, to adjust it you have to tweak your outboard device.

If you have some level indicator on your outboard device, the chances are they will tally very closely with the sound card mixer, and Reaper, ie. if you sound card mixer shows a clip, the same will be true on your sound card mixer, and that will also show up in Reaper.

Just adjust microphone sensitivity on the outboard device so you have a good input signal.

If this doesn't solve your problem, perhaps tell us precisely what you think the problem is?

Classicalmusic · 10-13-2008, 02:27 AM

Thanks Art Evans and Tedwood!

OK, it's clear that Reaper can't do anything and I must control the audio interface (M-Audio Fast Track Ultra 4-channel). But I still can't live with the idea that the sliders in the sound card's control panel are useless! As a matter of fact, what are they intended for?!?...

http://www.m-audio.com/images/global...ltra-Front.jpg

I was even wondering to replace the four original potentiometers with multiturns + dial knobs... it would be elegant and effective, but the original potentiometers have the pull-switch which activates the -20 dB pad, and this is quite an obstacle...
I think that inserting a preamplifier in the audio chain just to have precision dials would be a little wrong... and unnecessary and detrimental too, since it would raise the overall noise, and the Fast Track has all the necessary gain capability!

Quote:

I get the feeling you are fairly new to all this. Let me give you a tip from someone who has been at it for 40 years! In reality there is only one level - ok, slight exaggeration, but think of it like this. If you record a symphony orchestra, your mics will normally be quite high and some way back. The sound level reaching them will be appropriately reduced. If you are recording a guitar, you'll be a couple of feet away at most, and the sound level at the mic will therefore be effectively raised. On my stereo preamp I made a red mark years back that I line the knob up with. Nine times out of ten, regardless of what I'm recording (with my normal stereo pair) then that's the ballpark level. You'll quickly get to know the level that works best with your equipment - mark it and forget it. Then you'll be able to impress people no end by not needing level testing and so forth.

I am in these things since 1985 (celebrations for the tercentenary of J.S.Bach's birth) but at those times I utilized an analog equipment, DATs (if any, I can't remember) were far beyond my budget. I remember that in those times I could record orchestras and organs with the "only one level" you mentioned. But, I am scared to death to incur in digital clipping (analog tape decks were SO forgiving!) which can f*ck up an otherwise fine recording. And, with this equipment I am going to record mostly organs. Organ is heaven on earth to ear, but is the worst sonofabitch to record, its dynamic range is impressive, the low octave may start from as low as 8 Hz, and the SPL from close distance can reach the pain threshold. Not an easy client to serve. But this is OT here...

Coming back to Reaper, still about the PEAKS, I noted that the red peak indication remains lit for a long time after the peak has gone, and (most disturbing) also the 2-digit dB indication takes a long time to reset. I need it to go back displaying the LIVE level after not more than a couple of seconds, but although I browsed through all the settings and options, I could not find ant persistence/reset time!
Where did they hide it?...

Ollie · 10-13-2008, 03:16 AM

The red clip indicators stay lit for <2s if you uncheck the "Sticky clip indicators" checkbox in the preferences:

The numeric display of the highest peak level can only be reset by clicking on the meter or stopping playback (if configured in the prefs).

Art Evans · 10-13-2008, 04:23 AM

Quote:

But I still can't live with the idea that the sliders in the sound card's control panel are useless! As a matter of fact, what are they intended for?!?...

It's not a control panel, it's a monitoring panel allowing you to route inputs to outputs and control monitoring levels with or without effects (from what I've read about this device).

The monitoring software cannot control the input levels of the device for the same reason that Reaper cannot - the input stages are entirely analog. It's a pretty low-cost device - for a bigger budget you can get digitally controlled analog stages (Motu Traveler springs to mind), and that gives you knobs with readouts and software that can digitally control the analog preamp in just the same way as the controller knobs do.

But in the case of your device, you've got a conventional analog controlled analog preamp, feeding an analog to digital converter. Once the digitisation has been done, either the device's own monitoring software or Reaper can mess around with the digits. But like I said before, it's best to store the digits in their original pristine form, then play around with them afterwards.

Now as for your concerns about recording organs -

Quote:

But, I am scared to death to incur in digital clipping (analog tape decks were SO forgiving!) which can f*ck up an otherwise fine recording. And, with this equipment I am going to record mostly organs. Organ is heaven on earth to ear, but is the worst sonofabitch to record, its dynamic range is impressive, the low octave may start from as low as 8 Hz, and the SPL from close distance can reach the pain threshold. Not an easy client to serve. But this is OT here...

No, it's not OT, we're all as interested in recording and audio engineering as we're interested in Reaper. Reaper is just a tool - it's the audio that matters!

Digitally recording organs is radically easier than making analog recordings of them. As you say, they have an impressive dynamic range, but fortunately your audio interface has got a bigger one. 24 bits allows you to capture something like 148dB of dynamic range, probably better than your mics, and certainly better than the typical 60 to 70dB of an analog system. You don't need to be recording anywhere near to clipping. Many people regard -12dB as the maximum peak they plan to record. So if there's a chance of a soundcheck before the recording, get the organist to play a sustained chord on full organ (sustained because of the buildup of reflections in the location which can affect levels), set your level to -12dB (if recording in 24 bits), and the chances of the performance being 12dB louder are pretty minimal.

Actually organ performances are much more predicable in level than many other forms of music, because the organist is using pre-planned registration (well, that's what you hope!) and no matter how hard he hits the keys, it's not going to get any louder. In most other types of instrument the performer interacts more directly with the instrument, and is very liable to produce levels in performance significantly above levels in rehearsal.

LOSER · 10-13-2008, 10:54 AM

Quote:

Originally Posted by Classicalmusic

Wait a second... this is NOT clear.

So, if all the sliders in Reaper are for after-recording changes, what about the sliders in the audio card manager? They don't change the levels as well! Before this 4-channel audio interface, I used a smaller 2-channel one, with MIC and LINE stereo inputs: the sliders in its manager program DID CONTROL the recording level! I could memorize the settings and recall them later with absolute precision. So what's wrong now?...

If you are referring to Windows' volume control, then this is due to the fact that ASIO bypasses it (to achieve lower latency).
If this is some control application provided by M-audio, then you'd have to ask M-audio. However (-though I'm not familiar with the M-audio Fast Track-) since it features volume controls on the hardware I don't think the added another software volume control level to the driver/device itself, but I might be wrong.

Tedwood · 10-13-2008, 11:23 AM

I haven't seen the audio card manager but I have an M-audio card and likely to be similar. They do not assume you will be using a daw like Reaper so they have provided a basic mixer that can be used in other ways. The fact that you will be routing the audio channels straight into Reaper effectively makes it redundant, m-audio didn't know that though.

Classicalmusic · 10-13-2008, 11:29 AM

Quote:

Originally Posted by LOSER

If you are referring to Windows' volume control, then this is due to the fact that ASIO bypasses it (to achieve lower latency).

No no, I was not referring to the Windows mixer, but to the soundcard's (Trust) own control utility...

LOSER · 10-13-2008, 12:00 PM

Quote:

Originally Posted by Tedwood

I haven't seen the audio card manager but I have an M-audio card and likely to be similar. They do not assume you will be using a daw like Reaper so they have provided a basic mixer that can be used in other ways. The fact that you will be routing the audio channels straight into Reaper effectively makes it redundant, m-audio didn't know that though.

Quote:

Originally Posted by Classicalmusic

No no, I was not referring to the Windows mixer, but to the soundcard's (Trust) own control utility...

Ahh.. so it features its own volume control. Didn't know that. So in that case it should work, I assume. So maybe someone that has the unity can shed light on that, or you may consult the m-audio tech support or something.