Tech Tutorial: Matching Mics (and Ancillary Alliteration) Oct 4, 2017 14:48:40 GMT -8 Brittany Ann Phillips and kevlar like this
Post by duffyweber on Oct 4, 2017 14:48:40 GMT -8
First off, I'd like to say this isn't really to match mics PERMANENTLY*. This is a way to create a process so that if you're traveling with a more portable mic, you can send your audio engineer pickup lines that s/he's not going to have to work too hard to match to the rest of your work. (it's much, MUCH easier to match mics if you have access to both of them simultaneously, a luxury your sound engineer doesn't have, if you record out of your own studio/home.)
*I mean, it COULD be, but you're going to want to be more thorough than just my examples here...
This is JUST a way to get you started if you're going to, for example, be on the road, and don't want to send your sound engineer something so TOTALLY different from your other mic that they start wondering if their headphones have gone bad.
After you've perfected your process, you may want to send the end result to your favorite sound engineer, along with some audio from your main mic, just so they can tell you if you've done anything unforgivable in the process (such as eliminated all the bass below 137Hz.) ;P
Okay, so that said, there's several ways to match the sound of one mic to another, but TODAY, we are going to go for "quick, cheap and dirty."
Also, for this process, We're going to assume that MIC2 is the lower-quality travel mic. You DO NOT adjust your nice mic to mimic your cheapie.
For the "Cheap and Dirty" part I'm going to assume you're using Audacity. (Voxengo Span for Reaper has some good buzz about it, but I haven't personally played with it. However, the methodology will be the same, no matter which DAW you use.)
**********WARNING: this is the hard part**************
The first (and only difficult) thing to do is hook both mics up to Audacity simultaneously. This can be difficult if you're using USB mics along with XLR mics, or two USB mics of different brands/types. (if they're the same mic model, you're done. No matching needed, they're probably close enough and you don't need to fiddle. That said, if you're a perfectionist, read on...)
(ALSO: If you have access to two computers, you can skip this step, and just record the same performance simultaneously to two different computers, save the files and move them to one computer afterward.)
In Windows, ASIO4ALL and/or VoiceMeeter can both help you here. They are virtual interface control panels for sound devices, and you can create different channels. Simply install one or the other, set up the devices in the panel, then select your multi-channel devices so that you can record from both of your mics simultaneously.
Go to Audacity's Preferences panel, and select your recording source, set up multi-channel recording with your mics each as a channel.
Choose ASIO4ALL (Or VoiceMeeter) as your recording device in Audacity.
(I believe there's an easy way to do this in Reaper, as well, by simply creating multiple tracks and assigning them a recording device. I haven't tried it with USB mics...)
******* hard part is now over********************
Now that you're set up for recording both mics, you'll want to set them up next to each other, within a few inches, as you normally would record. Leave enough space so that they don't interfere with each other, but make it so that when you aim your voice at them, you are pretty much talking into both of them equally, and with proper mic technique.
I further suggest recording something short, but with plenty of vocal variance and range. Try to hit the top and bottom of your range when speaking, and, in general, do what's necessary to create a good overall profile of your voice. (A short but diverse sentence in your natural voice(s) is easier by far to work with than something really long when you're listening over and over and over and over and....)
Now, save the files.
Noise reduce the files before continuing. The mic's noise floors will be different, and rather than account for that, it's best (for now) just to eliminate it, as you'll noise reduce all professional production-grade audio anyway. [LINK: voiceacting.boards.net/thread/88/great-audition-noise-floor-removal ]
Now here's the fun part: open each file in an Audacity window. (The same window is handy, as you can bounce around easier, as long as you're comfortable working with multiple channels. Otherwise, put each in a separate window)
Select the entirety of the Mic 1 file, and then go to "Analyze" >> "Plot Spectrum"
Wow. That looks... daunting eh? Not to worry. It's just a visual representation of the amount of sound in each of the different Hz ranges of your voice. In other words, when you compare the two, you can spot the differences, and create an EQ pattern to make one match the other.
Make a note of the values of the plot where your dB axis and Hz axis meet. Write these values down.
You can then do the same for Mic 2.
Let's take this for example: [PIC: hulahulamoocow.com/recordingtips/MicMatch_PlotspecSM.png ]
You can see the two mics, (Mic1, Mic 2) look mostly the same but there are some obvious differences. The mic on the right has a sharper bass roll-off, and it's got a little TOO much on the higher end. (Mic 2 is a cheapie USB mic. With like, NO bass.)
NOTE: The plot markers shift based on the height of the highest peak so KEEP AN EYE ON YOUR NUMBERS and ignore the general shape of the graph.
Your goal is to adjust the EQ so that the plot of Mic2 more or less hits the same amplitude on the chart as Mic1. You can see where the green circles correspond on graph 1 and 3, but on the un-altered mic2, they're missing the mark.
(You can see I've intentionally taken off TOO much in the 8000 to 10000Hz range, just to illustrate the difference between Mic1, Mic 2, and Mic2 with the added adjustments. I marked that one in red instead of green.)
NOTE: This is a VERY SIMPLIFIED VERSION of the process. It's not going to make Mic2 sound EXACTLY like Mic 1, just much, much closer. You can further improve the sound by making minor adjustments, making the EQ pattern more complex, and using tools like dynamic range compression and the like to ensure that your travel mic sounds like your main mic.
Ultimately, this give you sort of a "starting place" and a good understanding of how and why one mic sounds different from the other and what you can do to fix (or alleviate) it.
Final thoughts: As I said before, I wouldn't just haul off and apply something like this to EVERYTHING I recorded with a travel mic. This is for delivering pickup lines to a much larger body of work, in order to give your engineer something workable that's going to be in line with what they're expecting. On the other hand, if the result doesn't render the audio unworkable, you go with a light touch, and you refrain from altering the audio to where it sounds overprocessed, there's no harm in incorporating your pattern into your cleaning of audio when it comes to that particular mic (Some DAW's allow a permanent application of EQ to all audio live while recording. Applying this in Audacity to your recorded audio wouldn't be any different.)
Go easy on it, be careful with it, and if you develop a decent ear for what you're doing you can get the most out of your mic!
Happy recording! ^_^