This is a great little app for the iPod Touch or iPhone available from the iTunes store. It outputs a sine, square, or sawtooth wave with variable pan and output gain. It also outputs white noise. Perfect for traveling engineers! I like it because I can use my studio's longer iPod cable and have my iPhone right next to the tape machine so it's easier to change frequencies and amplitude while I'm aligning the machine. I think my old HP tone generator and the signal generator plug-in have seen their last days. Plus, it's only 99 cents! One minor annoyance: when the phone shuts itself off, the audio mutes unlike iTunes, so you'll need to turn off the auto-lock mode or set it to several minutes instead of the default one minute. Maybe this will be fixed in a later revision. Akamatsu also authored the free Tap The Tempo app, but I like Audiodog's BPM Tap Tempo app better. ($0.99;

Tape Op is a bi-monthly magazine devoted to the art of record making.

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