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| VOLUME 12 | DECEMBER 2010 | FREE |
By Terry Downs
It's hard to imagine any applications for smart phones that have not been developed. Some are quite useless, but some are of tremendous value. There are several guitar tuner applications. You can install the app and use the microphone in the phone to tune the guitar. Especially for electric guitars, this can be problematic as backgound noise may be too loud. The best thing is to plug your guitar directly into your phone via the headphone jack. Most phone devices use a 3.5mm 4-conductor Tip-Ring-Ring-Sleeve (TRRS) jack and plug for headsets and headphones. The trick is knowing how to wire it up, so here we go.
I simply bought a 6ft guitar cable and cut off one of the 1/4" plugs. You can make your own from scratch if you like. The cut off end is stripped and attached to the 3.5mm 4-conductor Tip-Ring-Ring-Sleeve (TRRS) plug. The microphone input signal of the iPhone is the ring nearest to the ground sleeve as illustrated below.
Notice the tip and the ring nearest to the tip have concentric terminals. These are for the left and right audio outputs and are not used for this application. The terminal for the microphone ring is a small tab protruding from the plug body. That's fortunate because that appears to be the terminal easiest to solder to. Simply solder the center conductor of the coax (signal) to the tab and the ground braid to the ground lead, which is the long piece with the cable relief tangs. Below is another shot for clarity.
It's best to solder the ground before cinching the cable sheath into the cable relief tangs. Otherwise the heat from the soldering will melt the cable outer sheath.
If you use the parts linked below, you will find that the cable will not easily fit into the backshell of the plug. I drilled it out using a 3/16" bit. The cable then slid into the black plastic backshell easily.
I simply searched for a plug on the internet and found a company that has the plug and a cheap guitar cable. (No affiliation with supplier)
Qty (1) - 3.5mm
4-conductor Tip-Ring-Ring-Sleeve (TRRS) plug from kV Connection
Qty (1) - 6
FOOT 1/4in Mono Male To 1/4in Mono Phone Male Molded Audio Cable from kV Connection
Here is the completed cable.
There are numerous tuner apps from the price of free to $9.99, which is the cost for the Peterson Tuner app. It is the one I use (no affiliation). I have no idea how I was able to capture the iPhone screen below exactly when the treble E string was at 0.0 cents. I got lucky I guess, or maybe it's raw talent! You may want to check the accuracy on the app and phone you decide to use. The Strobosoft software I use on the PC is not accurate if the sound card clock is not accurate. If the source clock for the software is off, a calibration can be done if you have an accurate source reference, like a hand-held tuner with a 440Hz output tone.
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©2010 Terry Downs Music™
