Wireless Mic Helps Guitarist Rock Out Un-Tethered

Any guitarist knows what a tangled mess of cords can come out of a long jam session. One possible solution would be to get a wireless guitar system, however, such a setup can range in price from about 50 to several hundred dollars. That’s a big price to pay for not having to untangle some guitar cords.

[mattthegamer463] wanted a wireless setup but didn’t want to spend the cash on one. He’s a tinkerer and had a spare wireless microphone setup hanging around. So, he decided to try converting the wireless mic to work with his guitar.

Both microphones and guitar pickups work in similar manner. In a guitar pickup, the vibrating guitar string disturbs a magnetic field and induces a current in the pickup’s coil. That current is the guitar’s signal. Microphones are similar, air pressure waves vibrate a diaphragm or ribbon which then disturbs a magnetic field to create the signal. [mattthegamer463]  thought these principles were close enough for him to make quick work of the conversion.

First, the microphone was taken apart and the diaphragm module was removed, cutting the two wires that ran into the mic’s handle. A hole was then drilled into the wind screen so a 1/4″ jack could be installed. [mattthegamer463] states that it’s important to electrically isolate the jack from the wind screen or the signal and ground wires will short and the project won’t work. The two wires that were previously connected to the diaphragm module are then soldered to the newly added jack and the mic was screwed back together.

To use it, a patch cord is run from the guitar into the jack on the mic. The stock wireless receiver from the mic system is then plugged into the guitar amp. The modified ‘mic’ now transmits the guitar signals to the guitar amp! You may think it would be awkward to hold that mic while jamming. You’d be right if [mattthegamer463] didn’t come up with a nice looking aluminum and rubber belt clip.

16 thoughts on “Wireless Mic Helps Guitarist Rock Out Un-Tethered

  1. dont usw people use their smartphones and bluetooth for such stuff? via otg one can plug in a stereo line in, so one can transmit guitar and mic simultanously( otherwise the usual headphone jack has one input channel) so only thing one needs is a reciever and those start at 5 €

    1. Good luck with latency then. The above solution isn’t even technically right as it almost certainly injects the electret mic DC supply into the guitar, but surely it’s much more playable than any solution involving a cellphone and bluetooth.

      1. He said diaphragm, as in dynamic. The hookup may still be wrong. The mic is hot on both sides, the circuit may be also. Or it is not differential just hot to ground on one side only. The correct side needs to go to guitar ground.
        Even if no latency, Bluetooth isn’t the kind of fuzz or sound any guitarist would like to hear. More like tone sucker.

      2. Most handheld wireless mics are dynamic capsules (moving coil), so there probably isn’t a bias/electret supply in there.

        Nice hack if you happen to have some spare time, a handheld radio mic that you don’t need, and you need a instrument transmitter. If lacking spare time or a transmitter, there are plenty of cheap instrument wireless transmitters around (usually beltpack/lavalier transmitters with a jack cable and blocking cap, as lavalier mics do need a bias supply)

    2. Definitely a hack, good use of available gear to solve a problem. That said, microphones are sometimes similar to guitar pickups and sometimes not, you can often pick up Karaoke wireless mics in thrift stores and yard sales for way less than a guitar wireless rig, but…….. Guitar pickups are usually high impedance coils that want to see a high impedance load and microphones are typically much lower impedance if they are dynamic and if they are condenser you have the other consideration of DC voltage to deal with as well. The comment about not using a grounded 1/4″ jack is indicative of something else not wired properly as one usually wants the circuit to be shielded from external interference. Here’s a link which might get you started concerning specifics of guitar preamp circuitry – http://www.till.com/articles/GuitarPreamp/
      By the way, I have found that USB game mics, Rock Band, Guitar Hero, etc. make good 16 bit guitar A-D interfaces if you just cut the mic off and replace with a 1/4″ plug, impedance seems to be OK and I have picked these up for as little as a buck at the thrift store, don’t know if they make wireless versions of these.

    3. Signals coming out of a guitar are not at line level unless the guitar is using “active” pickups, in which case the guitar has an onboard preamp. Passive pickup signals would have to be brought up to line level.

      1. Signal from a microphone is also not line level, even condenser mics require a preamp so the mic input to xmiter is low level and should have a 1M resistor across it to work properly with a passive guitar pickup, active pickup would likely overload xmiter input and would need a pad to work properly. All that said cheap wireless have limited range and are subject to interference, have limited dynamic range and frequency response, often they use FM radio band. Good, hifi, reliable wireless systems are expensive for a reason. Cheesey wireless can have a distinct charm of their own however, so don’t let that stop you from hacking!

  2. I’m about to try the same thing with the Adafruit FM transmitter breakout, the Sparkfun FM receiver breakout, and two Trinket Pros powered with LiPo batteries. Both chips support the extended Japanese FM band which goes down to 74MHz, so in my neighborhood there’s a good chance 74-87MHz is free and clear. Another pair of breakouts on an adjacent frequency and you’ve got wireless in-ear monitors too.

    I was actually surprised to find this here this morning; just yesterday I was Googling for this sort of project and wasn’t finding much that was any good; people hacking Griffin iTrips and using a transistor radio as their receiver. There is interest for such a thing, and honestly I wish somebody would do a cheap IC that would work in the ISM band that commercial wireless units use. It’s license free at reasonable power levels, unlike FM. I’m not anti-free-market, but some of us would gladly pay $40 for decade-old wireless technology until we can afford the $1,200 Sennhiesers.

    1. There are many 2.4GHz wireless audio sending modules on aliexpress that would do what you are wanting.

      Usually the basis of things like wireless rear speakers and similar. Also some 5.8GHz ones as well but I have not tried any of those.

      1. I would appreciate a link; I went to AliExpress and I scrolled through page after page of RC controllers but nothing that does audio. I think that if you’re doing more up there than spurious transmissions you mess up cordless phones and wireless routers, don’t you? Remember, latency is an issue, so anything that converts it to digital for the trip.

        1. Sorry, never saw the email from hackaday about this reply.

          http://www.aliexpress.com/store/product/2-4G-wireless-digital-audio-module-wireless-speaker-transceiver-wireless-speaker-adapter-C1B2/1337009_32241087822.html

          is one of the ones, it looks like one that a friend got a few of for their hanging speaker project. Worked ok even in a room with lots of wifi activity.

          There are also these ones – http://www.aliexpress.com/store/product/5-8G-Module-Wireless-Digital-Audio-Module-Wireless-Stereo-Module/224898_2050560093.html

          Its chinese new year at the moment, lots of sellers take their listings down while they are on holiday because people buy things and dont read and get angry when they dont ship for 2 weeks, so check back a bit later and you should see more.

  3. Any lost frequencies, like lower notes or complex harmonics from the highs? Voice-oriented mics *might* not be built to transmit stuff outside of a normal speaking voice range, depending on how the device is designed

    PS if your immediate reaction is to scoff, please consider for a moment what you might hear (or, rather, not hear) if you tried to use a phone to listen to your friend’s stereo… Even if your cellphone’s speakerphone mode uses the very same speaker that normally gets you halfdecent mp3 playback, the frequency cutoffs of the voice call service used will murder the music signal

    1. Harmonics are generally made in the pedals and amp, what comes out of the pickups is pretty clean and not extending that high up. Vocal wireless mics have way more range than a telephone call does.

      I would be more worried about transients causing it to overmodulate and the PLL on the reciver briefly losing lock etc. Huge dynamic range in a guitar output.

  4. Ok, do this is pretty old but I was looking so someone else might be as well. Rockband and the Konami mics are even cheaper now ( got two at the dump) so I decided I’d like to see if you could wire it up to my guitar instead. I put a female 1/4″ Jack on mine and kept the mic cord as short as possible – figuring that my guitar cord was better quality than the rockband mic. Everything was fine but I found that the guitar played very “hot”. Overdriven sound wasn’t bad but I have a bass as well and wanted the opportunity for a clean signal. I figured the impedance was to blame so I’ve just soldered a 10k ohm resistor in series with the jack. I’m ready to try it out now… I wish I had put a switch in so I could go back and forth to compare the two signals but if it works better I’ll most likely go back and put in a passive lp filter for the bass anyway so no harm no foul. I’ll report back if I don’t blow myself up somehow…

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