Using the built in microphone, or the headset mic, has always meant not being able to hear the output if you were using an acoustic guitar. For electric guitar, not hearing an output at all is a problem, as plugging a device with audio input into the headphone jack mutes the built-in speaker.
So the only way to do this effectively without a USB 'hack' is through a hardware device such as the iRig from IK Multimedia. This handles the audio input and importantly provides an audio output or monitor via a standard 1/8" headphone jack.
Plug your headphones into this output for quiet practice without disturbing anyone else, or connect it to speakers, a sound system, a guitar amp or even a PA system for full-on live sound.
We had no problems at all connecting a guitar straight away and after confirming the warning about turning down the volume before we start, especially with headphones connected, we were off and rocking (well, we made noise with our guitar).
Using iRig with Apps
The iRig was recognised as an input device by every app we tried without fail. This included iPad specific apps Amplitube for iPad (look out for our review soon), StompBox and StudioTrack (read our full StudioTrack review here).
We also tried iRig with a number of iPhone audio apps including:
A Few Issues
For the most part there were no issues with iRig and the above apps, the only problem we did have was with AmpKit by Agile Partners and Peavey. The main issue here was high pitched feedback at anything but extremely low input levels.
This is not a review of AmpKit, that is for a future post, but the extremely high gain Peavey amps simulated in AmpKit are a particular challenge to iRig, and Agile Partners recommend, of course, their partner Peavey's AmpKit Link audio interface.
This is a hardware device designed for exactly the same purpose as iRig, but with active (battery powered) circuitry designed to eliminate the feedback inherent with the unpowered versions like iRig.
We hope to get a review to you soon for both the AmpKit link and AmpKit app, but we have been holding out for an iPad specific version, which is apparently in the works.
Sidenote: Feedback Warning - Follow the Instructions
As we mentioned above, feedback with these kinds of devices can be a problem due to impedance issues. The scant instructions give just the essentials for setting up the iRig, but they do warn that using a 1/8" to 1/4" adapter on the headphone output will cause audio feedback.
Well, we wondered about this and as we only had the 1/8" to 1/4" adapter available to us, we tried it anyway.
We had no feedback issues with this adapter when connecting to a home cinema surround sound amplifier, but once we connected the iRig to our guitar amp (clean channel, no effects, middled tone controls across the board) and engaged a high gain amp model in the software, specifically the Metal amp, we had an immediate problem with piercing audio feedback screeching out from our amp speaker at any volume setting.
Our recommendation is to take heed of the instructions and get a cable matching IK Multimedia's suggestion. We are guessing that similar feedback will be experienced with a PA system too (although we have not been able to test this).
As you can see in the above instructions, the cable setup recommended is an 1/8" stereo connector from the headphone socket out to a twin RCA (using the left one to connect to the amplifier/PA) or 1/8" to 2 x 1/4" Mono jacks.
We obtained one of the latter cables from eBay for about £4 (pictured below) and since using this new cable we almost never received feedback when using the iRig connected to the guitar amp, except in the situation mentioned above with the AmpKit app.
Not Just For Guitars
Whilst the primary purpose of iRig is to get a guitar input into your iDevice and a monitor out, you can also use it to input other audio signals. We successfully recorded audio from a Bass guitar and a passive vocal microphone (although audio hiss was an issue) as well as an Acousto/Electric guitar from both its 1/4" and XLR output. IK Multimedia's website also makes mention of line level input from Keyboards, Synthesizers and mixers and we have no reason to doubt it works with these audio sources too.
We have had a great time using and testing the iRig interface and we can recommend it wholeheartedly for iPad musicians or anyone wanting to get sound into their iDevice whilst monitoring the output simultaneously.
iRig is available from most music stores and online retailers for around £25 ($39.99).