Need to edit an audio file, but you don’t have your computer with you? Need some pink noise, but don’t have your noise-plug? Think you know the frequency that’s feeding back, but can’t seem to squash it? Don’t worry. You guessed it: There’s an app for that.

I’m right up there in sound dork-dom, but even I didn’t have some of the best new audio-centric apps on my phone, as it turns out. In general, my “app-etite” is a little lackluster. I’m pretty pleased that my phone emails, sends texts, takes pictures, browses the web, and, oh yeah, usually makes phone calls. My most handy apps are probably BrewHop and Facebook, but it turns out, with a bit of research and purchasing, my iPhone (or iPad, if I had one) could be a fairly useful audio companion in my pocket.

In my research, which honestly came far from encompassing all audio apps, I ended up with three that I really liked and had generally good reviews. These three are new or have been updated in the last year. Each accomplishes a different task, and there were easily other contenders that could do the same thing, just possibly not as well, as quickly, or as sleekly, in my opinion. Your own experience may vary, of course. All are available at the Apple App Store.

Performance Audio’s Audio Tool

A versatile six-part app, Audio Tool has been developed by Performance Audio. Audio Tool greets you with a very forward disclaimer: “Performance Audio has made every effort to make this application as accurate and reliable as possible. However, this application is supplied for entertainment purposes only.” Fair enough, I actually appreciate that. I mean, this is your phone we’re talking about. It’s a tool, as its name suggests, but doesn’t claim to be a professional audio device...yet.

That said, it does very well. Part one is a thorough decibel meter, Decibel Meter Pro 2. Using the microphone on your phone as a measurement mic, it measures the dB of incoming audio, and it does so with fairly remarkable accuracy. Its layout is easy to read and displays a lot of information cleanly. Centered around a wheel, it displays the average dB with both a moving needle and a large numerical readout. There’s also a peak needle and readout display, as well as a maximum dB meter. Taking this little app into real-world usability is the inclusion of the four most common weighting filter options: dBA, dBB, dBC and dBZ. Control options keep your phone from sleeping, adjusting the mic sensitivity, and calibrating the mic.

Part two is Microphone Pro. It’s a basic little app that turns your phone into a microphone. Whatever your onboard mic picks up is routed to the headphone jack. There’s an on/off button and a volume control fader. In my brief test, it worked pretty well. What I heard in my headphones sounded clean and fairly accurate. Obviously, the sound is only as good as the mic on your phone, but the app didn’t seem to degrade the signal. There was noticeable latency, but for less-than-critical applications, it should be okay. So next time you’re short a mic on a gig, whip out your phone and adaptor cable. Comments I saw included people using the app as a talkback mic, and I can imagine that working pretty well.

Part three is Tone Generator Pro, and it’s actually pretty great for a tone generator. All audio feeds either through your built-in speaker or, if a cable is connected, your headphone jack, which clearly you could connect to a sound system. It will play sine, square, sawtooth, reverse sawtooth, and triangle waves at any volume and frequency. There are buttons for your go-to frequencies, or you can select frequencies with an overly sensitive virtual fader or an up/down button that skips to frequencies incrementally. On my phone, it showed me that the frequency response of the onboard speaker was from about 160Hz to 15kHz and that my dog has good hearing. Tone Generator Pro also has a noise section that plays pink or white noise with adjustable volume and a sweep section that allows you to smoothly sweep through frequencies in three sections (2Hz to 200Hz, 20Hz to 2kHz, and 200Hz to 20kHz), using a pretty smooth and controllable jog wheel.

Part four is the straightforward Tempo Pro. It’s a slick metronome that easily lets you set your tempo (complete with the tempo markings), volume, and time signature. It has different user settings, including sounds, screen flashing, sleep control, and more. The only thing I noticed is that, when my phone went to sleep, the metronome continued (good), but the tempo stuttered for a moment (not so good).

Rounding out the tools are parts five and six: Bit Calc Pro and Audio Atlas. These are handy, if not as application-oriented. Bit Calc Pro lets you plan your next recording session. You tell it about your session: how many tracks you’re going to record, at what bit depth and sample rate, etc. Your next move depends on what you know or don’t know. If you know you need to record for 30 minutes, it will tell you how much hard drive space you need. Or, if you know you only have 1GB of space on your drive, it will tell you how long you can record. With this tool, I now know that, if I’m recording in stereo at 16-bit and 96k, and I only have room for 250MB, I’m limited to 11:22 of recording—good to know.

Finally, Audio Atlas completes the package. Audio Atlas is a very complete collection of audio terms, sorted alphabetically. You look up a term, and it will tell you about it or give you a definition. I was pleased to find that it’s really quite complete. It even had a definition and description for “tape bias”—sort of funny, if you think about it.

Alex Wiltschko’s Octave

Octave from developer Alex Wiltschko is a realtime analyzer (RTA) for your iPhone. Using your onboard speaker, Octave displays a realtime graph showing the incoming frequencies and their SPLs. Octave uses ANSI-certified time-domain analysis instead of Fast-Fourier Transform (FFT) techniques. The results are quite consistent with what I see with other more professional RTAs.

Sitting by my computer, I see my room tone peaks around 250Hz and that most of my whistling is between 1kHz and 2kHz. You can pick the bandwidth (1/3, 1/6, or 1/12 octave) and the time decay/graph speed. It also shows you a trace of the maximum curve, which can be reset by triple tapping the display. If you turn on “show maximum,” a bar across the top of the display will constantly show you the peak signal in frequency, amplitude (in dB), and note.

There are several other RTA apps out there, but this one seemed the most useful and user-friendly. Wiltschko also developed two other great apps: Fourier, an easy FFT analyzer, and oScope, a simple and powerful oscilloscope. All of his work has a clean and easy-to-use look to it—very “appy” apps.

TwistedWave Audio Editor

Okay, now this is getting crazy. TwistedWave lets you edit audio waveforms on your phone. Granted, this looks much easier and better on an iPad, but still, the app is pretty great, even on your phone.

The TwistedWave app is based on, and extremely similar to, the company’s full-fledged audio editor for Mac. Both the computer and app versions let you do fairly comprehensive editing of either mono or stereo tracks. It won’t do multiple tracks beyond stereo, so this is all in-line editing, like Bias’ Peak or Digidesign’s Sound Designer II. Think: voiceover artists or hopeful voice over artists. There are other apps that allow for multiple tracks, but what they gain in more tracks, they lack in completeness.

It’s very easy to get around the TwistedWave app. You can create a new document and then record into the program using the onboard mic on your phone, or you can import audio from your iTunes on your phone, from an email attachment, or via iTunes file sharing from your computer. Most common formats are supported, including MP3, WAV, and SD2.

You can see your waveforms via an overview screen along the top, and then you zoom-in and edit in the main display. Using standard drag, pinch, and tap gestures, you can select portions of the audio and do a number of processes. Without leaving the main screen, you can copy and paste a selection, and have multiple levels of undo and redo. Or, with the selection highlighted, you can go to the effect screen and select a bunch of configurable DSP effects, including amplify, normalize, fade-in, fade-out, silence (i.e., cut the audio but preserve the time), insert silence (i.e., add time), EQ filters (high- and low-pass, and shelf), delay (with parameters to control), compression (with parameters to control), and pitch and speed change. Each of these effects can be instantly previewed and/or applied—really quite impressive.

And then, when you’re on-the-go masterpiece is done, you can easily export your work and pick a format, including Advanced Audio Coding (AAC) compression for smaller files. You can email it, send it to a Dropbox, send it to your iTunes, or send it to any FTP site—crazy, just crazy. TwistedWave could be a lifesaver.

The world of apps is really amazing, and to be sure, there are other great and not-so-great audio-focused apps out there. These three apps were easy to find, relatively cheap to purchase, easy to use, and definitely serve a purpose. Beyond messing around with them, I can see myself actually using them in my work. I’d love to see more manufacturers of gear producing their own apps. Yamaha has an impressive app that lets you manipulate some common monitor mixing controls on the M7CL console. I like that idea and hope other manufacturers go down the app road. For now, these three apps show that developers are doing great work in the audio world and that, indeed, there is an app for that.