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Good Old Fashioned Testing?
Old 19th May 2006
  #1
Lives for gear
 

Good Old Fashioned Testing?

What happened to good old fashioned testing?

I see many people complain about this or that or one thing or the other when it comes to technical problems with daws, recording, mixing etc. There used to be a time when an "engineer" who thought there was a technical problem in the studio system would logically test things and try to work it out.

Now? Run to the forum and ask a bunch of people first. Kind of hampers development huh? Sure, you might find an answer faster but how does that help you grow as an engineer?

I've gotten plenty of help with technical problems from audio forums, don't get me wrong. They're a valuable resource. But there is something to be said for learning how to _logically_ approach an engineering issue to approach a solution on your own. You may not find it but you'll learn _something_ ...

Stay tuned... I'll put an example in a new post... phone's ringing.

Lawrence
Old 19th May 2006
  #2
Lives for gear
 

I'll use tracking to the daw from an MPC as the example. That topic pops up here every couple of months it seems. I've not yet read a poster of the "sounding different" problem with MPC transfers relate the results of any meaningful and conclusive tests.

How many people who regularly transfer tracks from MPC's to daw (and then complain about things "not sounding the same") have actually taken the time to logically test that transfer process to prove how accurate, or inaccurate it might be? Some just come here to ask what others might think is the problem (which is fine btw, nothing wrong with that ) though every studio and it's equipment is different. There's thousands of variables.

When I say "logically test" I don't mean by using your ears. By proving what is true or not true by _repetitive_ testing. "Repetitive" is the key word here (if I spelled that right).

How do you do that? Here's a very simple example of testing transfer timing accuracy. Your sound can be "different" from other causes but timing (the MPC's bedrock from what I hear) could have a lot to do with it.

1. Record a perfectly quantized 1/4 note transient signal (sidestick?) on the MPC . Sync your MPC to your daw and record that signal to a daw track.

2. Just for kicks... before proceeding any further, play that recorded track along with the MPC and see if they sound in time. If you hear obvious flamming you MIGHT have a problem but not necessarily. It's the timing of the daw tracks against each other that count. Even if they don't flam we're not quite done yet...

3. Record a new track from the same source. Now go into the daw and zoom in on the two tracks peaks and see how close they are. Take note of the difference if any. +5ms? 0ms? -7ms? Write it down. If those two are placed exactly alike or very, very close, that's a good thing. Well... maybe that's a good thing, you don't know quite yet.

4. Guess what? Do it again, and again and again and again. Why? You want to see what happens in a test that mimics working conditions. When you move beats to daw you might transfer 5-10-15 parts. Transferring two tracks and checking the timing doesn't tell you much. If the timing started to change after the 4th pass you'd never know. Do it 10-15 times. The same signal recorded to 15 different tracks (one at a time) while the MPC is synced to the daw.

5. Now zoom in to a peak in the first recorded track and set the position of the song there on the timeline so you have the position line drawn there across all of the tracks. Scroll down and look at all of the tracks and see if those peaks are on that line. See if they line up. Best case scenario? they are in the same spot as the first track. Not so good scenario? They're moving around as in +7ms, -7ms, dead on, +8 ms etc.

If they're moving around write the values down so you can look at the numbers and see if there is a pattern. Progressively later as tracks build up? Erase the tracks, reset your audio hardware and do it again. Write it down. Did the results change? Reset the MPC erase the daw tracks and do it again. Did the results change?

========== So what? =============

So you've just done some basic "engineering". You used logical test procedures to try to identify and correct (if required) what you feel may be a potential problem. "Engineering" is more than just recording and mixing. You've tested to help you begin to "engineer" your audio tracks around a potential problem that could affect your result... i.e. "sounds different". This is a big part of engineering.
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Note: This is about the time when someone says... "that's just bull**** and a waste of time, just go make music." Fine. Go ahead and make music. Me? I'm not a musician. I'm an engineer. If I were a musician I'd be practicing my instrument. In my case the studio is my instrument. I tune it regularly and I like to know exactly what it's doing.
===============================

So the test is completed right? Well no...

Go back and set your MPC to a swing percentage that you might normally use and do it again and see if the timing differences between multiple recorded tracks change more or less or not at all. Or go back and record those 1/4 notes on 15 seperate MPC tracks and then transfer those one at a time and see if the results change. Don't think that's possible? How do you know?

What about switching the midi input port that you sync to to a different input (if there is one) and doing it again? Or switching cables? These are the kinds of tedious things that "engineers" in many fields do.

What about powering down for an hour and doing it again immediately on powering up? Or letting the gear warm up for 20 min and comparing it to the "cold" results. What if your midi sync device works fine on powerup but gradually starts to "fade" or "drift" slightly being 8ms out of time after warming up or vice versa? How would you know? Write down the results so you can determine which method delivers the most stable timing.

===============================

All that seems really obsessive for sure. Point being, if I was seriously "irritated" about my MPC transfers (don't own one btw) sounding "noticably different" I'd "engineer" a solution. That's what engineers do. They obsess over minute details so when you drive your car over a bridge it won't collapse.

In this case the transfer process is the "bridge" and the MPC 'beat' is the car you need to drive over it. There's a way to get over there "safely" (for you people who have 'noticably audible differences after transfers') but it's not going to announce itself. You gotta go find it. That's what engineering is.
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Take the time to develop and logically test some things when you have problems (or actually just for the fun of it) and you'd be surprised what you might learn about your unique setup... the above being a very simple (but very obsessive) example over MPC transfers. Only YOU can arm yourself with information about the behavior of YOUR unique studio setup. It takes time though.

If you're a practicing working musician don't bother with such minutia. Find a good engineer to work with for your demos.

Wanna be an engineer? Block a few hours for yourself and get started.

Lawrence
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