OVERVIEW:
After testing another affordable ("cheap") wireless mic system (and after reviewing the first one with a YouTube video) I started wondering if there was a way to make them work better...without spending much money. I think I found an easy fix: boost the audio with a mini headphone amplifier, before (or after) sending the signal to the capture device (be it the camera or an external audio recorder).
ABOVE: There are many affordable wireless mic systems out there, but they often produce too much (unwanted) noise...yet I think I've figured out a workaround!
WHY BOTHER WITH CHEAP WIRELESS SYSTEMS?
Well, because I'm cheap, but most importantly, because there are so many of these cheap wireless mic systems around, you'll probably run into one at some point, so it's good to know how to make them tolerable.
WHAT'S THE "REAL" PROBLEM?
Most times the problem is that a cheap (inexpensive) wireless mic system produces too much (unwanted) "noise". This means the signal-to-noise ratio is bad, and that means the recording will contain "hiss" or other non-signal noise which could ruin your recording. The source of this problem is often a low-quality pre-amplifier and/or a low quality radio (i.e. the transmitter and receiver).
NOTE: Sometimes you can even leave the gain on the wireless unit high (knowing that it will capture some RF noise) but then turn down the record level of the audio capture device to "hide" the noise floor.
WHAT'S THE SOLUTION (SHORT VERSION)?
The short version is, buy a mini plug (headphone) amplifier like this one #ad pass the audio through it, and experiment with turning the gain of the wireless transmitter(s) down until you hear the signal improve (make sure to listen with a pair of accurate headphones, and an audio interface with an accurate DAC).
STEP 1 TEST THE WIRELESS SYSTEM (AS-IS)
This step may seem useless if you already know the wireless mic system (or 3.5mm mic) is bad (i.e. has a poor signal-to-noise ratio). However, SOME inexpensive microphone/receiver combinations sound pretty clean right out of the box, so it's worth a try. If you try the mic system as-is and it works good, then stop here. This isn't very common for lower cost wireless systems however, so you'll most likely you'll have to move on to STEP 2.
ABOVE: The kit I used to "fix" my inexpensive wireless microphone system included a mini jack (3.5mm) headphone amplifier (this one #ad was $30 US) a cell phone mount #ad and 3.5mm aux cables #ad .
STEP 2 PICK THE RIGHT "PROXIMITY"
Before we talk about the "secret sauce" I should mention one other thing to keep in mind, that often solves most of the problem; make sure the mic is close enough to the sound source (i.e. the "proximity".) When the mic is not close enough, you're usually forced to turn the gain up, and that reveals the self-noise of the mic, the radio (transmitter/receiver) and/or the audio recorder itself. To learn more about what distance I prefer to use mics at check out my blog post on my "5 Proximities for Mics".
STEP 3 ADD A MINI JACK (HEADPHONE) AMPLIFIER
This is the fun part and the "secret sauce" to this budget filmmaking audio hack: buy a mini (3.5mm) headphone amplifier (I used this one #ad ) and attach it to your rig (I use a cell phone mount #ad ). There are a number of decent mini jack (3.5mm) headphone adapters on Amazon (ranging from inexpensive to VERY expensive) but the one I used was only $30 US (at the time of publishing) and it worked quite well! Adding this little headphone amplifier provides the option of boosting your level either before, or after, sending the signal through the wireless system. The advantage is that it's multi-stage amplification, which doesn't push a single amplifier beyond its range of clean sound. As I mentioned, this method is a cheap and hacky one, but the test results have been great.
STEP 4 TURN ON THE MIC'S BOOST (IF NEEDED)
Some microphones (such as the Rode VideoMic Pro #ad and the Shure VP83 #ad ) have a +20 gain boost switch (and some just have a +10, like the old Rode VideoMic non-pro). Sometimes using this boost in combination with both the lower gain setting (from STEP 2) and the 3.5mm headphone amplifier (from STEP 3) can result in even cleaner-sounding audio (i.e. less hiss, lower "noise floor", etc.)
STEP 5 TURN DOWN THE GAIN ON YOUR CAMERA
You may already do this, and this should have been STEP 1 but I'm leaving it as the last step because it does require performing the other steps for this approach to work. If you haven't tried turning your camera's preamp down yet, give it a try now, and you should notice that it really does improve the quality of the audio.
CONCLUSION:
So don't give up on that cheap wireless system you bought for less than $100 US yet, but if the audio DOESN'T improve after doing all of this (which it should) then first try upgrading the lavalier (clip-on) microphone and then if that's not good enough, you could go for a more expensive wireless audio system (which I hope to be testing in the future).
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