Tuesday, August 20th, 2019


By editorApril 30, 2012


Alesis iO Dock

Alesis were really ahead of the game in getting the iO DOCK out on the market whilst most other manufacturers were still relying on connecting to the iPad via the audio facilities of Apple’s Camera adapter.

Considering it’s low cost and the availability of GarageBand for iPad, the Alesis i/O DOCK seemed a very good proposition for capturing new song ideas with a level of audio performance certainly good enough for serious demo use.

So how has it panned out in practice?

I purchased the Alesis iO DOCK pretty well on the same day as my iPAD2 arrived from Apple UK about 2 weeks after the iPAD2 was launched. Alesis had to contend with the major inconvenience that the iO DOCK had been designed for the original thicker bodied iPAD and a filler ‘insert’ had to be designed and got out to dealers. Thankfully my iO DOCK arrived with the insert which was simple to install and you quickly forget it’s there.

Despite is visually plastic construction, I’ve found the iO DOCK to be robust and it’s easy to slide my iPAD into the sleeve. I absolutely love the fact that once ‘mated’, the iPAD and iO DOCK form a physically solid single interface; no additional flimsy cables and the wedge shape of the iO DOCK makes both operating the iPAD touch screen and connecting audio and MIDI cables really easy.

The iO DOCK comes with a mains adapter and critically charges the iPAD when installed. It does have a power switch and thoughtfully designed cable retention device to avoid the dc power cable from being accidentally pulled out. Whoever headed up the design of the iO DOCK has really done a good job.

Let’s briefly run through the facilities;

Two channel inputs each with a combo socket so you can connect either mic or line level sources. Switchable +48V phantom powering, and input 2 can also be switched for a high impedance instrument input.

You get balanced line level main analogue outputs suitable for connecting to a loudspeaker monitoring system; with level control, and a separate stereo headphone output with it’s own level control.

When recording you have the option of direct zero latency monitoring of whatever you’re feeding into the unit.

MIDI is fully catered for with both USB and ‘traditional’ 5-pin DIN MIDI connectors and there’s a footswitch which I guess is designed to allow hands free start-stop recording but this is not catered for in Apple’s Garageband (but may be in other recording apps.

Then my only small grip. I was really excited to see a composite video output on the rear of the unit. So I rushed off and connected this to my large screen TV expecting to see GarageBand in all its glory! But I didn’t. I could call up my photo album and anything else which doesn’t rely on the mirror function in the iPad, so for now that’s an unresolved issue for me.Audio Performance

Next I ran the iO DOCK through my Neutrik Audio Test set and had a look at audio quality. Here’s a quick spec sheet of what I measured via the Neutrik;

Replay of a -1dBFS tone to main monitor output, on-screen fader set to ‘0’

  • Level range is ‘off’ to +9.7dBu Left and Right output levels match to within 0.1dB at 0dBu; within 0.5dB down to -20dB and to within 2dB at -40dB This is pretty good performance and means you’ll be getting an accurate representation of the stereo balance of your recording.
  • Output noise when replaying a ‘silent’ track is -98dBu, noise content is reasonably clean.
  • Distortion 0.007% at 1kHz
  • Crosstalk, Left to Right measured -75dB at 1kHz
  • Crosstalk, Right to Left measured -83dB at 1kHz

Line Input (measured using direct monitoring facility)

  • Gain range is -20 to +23dB
  • Maximum input is +21dBu
  • Distortion (0dBu in/out)
  • 1kHz 0.004%, 20Hz 0.005%, 20kHz 0.003% (30kHz filter!)
  • Frequency response -0.5dB at 20Hz and 44kHz
  • Noise -90dBu : 22Hz to 22kHz; noise content clean.

Microphone Input (measured using direct monitoring facility)

  • Gain range is 0 to +42dB
  • Maximum input is +2dBu
  • Distortion (-20dBu in, 20dB of gain applied)  1kHz 0.007%, 20Hz 0.015%, 20kHz 0.006% (30kHz filter)
  • Frequency Response -0.5dB at 20Hz and 71kHz
  • EIN 125.4dB (at maximum gain of 42dB)
  • Phantom Power measures 51V (even when loaded with a microphone)

Recorded audio performance (remember we’re limited to 16bit 44.1kHz with my test Garageband app)

  • 0dBu Line in, Line out ; set up to record at -3dBFS
  • Distortion 1kHz 0.008%, 20Hz 0.013%, 15kHz 0.087% (then rises quick sharply as you approach the half-sampling frequency limit)
  • Frequency Response -0.3dB at 20Hz and 20kHz
  • Noise -88dbu

So within the limitations of 16bit 44.1kHz recording, the only real issue is rising distortion as you exceed 15kHz, but for all practical purposes the audio performance is fine for serious demo use.

Maximum mic gain is quite low at 42dB but I found it manageable using a condenser microphone and if you get stuck for gain then you can always bring an external mic pre-amp into play.

MIDI connection worked fine although you are advised to update to the latest firmware version via a utility available on the Alesis website. MIDI is mirrored in and out of both the USB and DIN MIDI sockets so you’ve got the option of sending and receiving MIDI data to and from your PC in addition to your iPAD app. MIDI response using an external keyboard is good.

When launched, the iO DOCK was the first really practical ‘all in one’ interface for the iPAD and still sets the standard at this (or maybe any) price point. (For those wanting more inputs and the beginnings of an on board hardware mixer then the newly released four channel Alesis iO Mix is worth reviewing.) Using the (very) low cost Garageband software from Apple allows you to record and playback up to eight mono or stereo 16 bit 44.1kHz tracks. After 10 minutes getting set up the iO DOCK with a mic and guitar, I had dialled up a nice groove from Garageband’s built in drum kit and I was composing. This is how music composition should be! Highly recommended.

Best features : Quick and easy to use. Sounds great.

Weakest points : At this price point, none

Rating : 9/10

www.alesis.comManufacturer’s published specification


  • 2 x XLR-1/4″ Balanced TRS
  • Individual gain controls
  • Phantom power, switchable
  • Guitar (high-impedance) switch on Input 2


Balanced XLR Mic

  • Max -45 dBV
  • Min -3 dBV

Balanced 1/4“ TRS Mic/Line

  • Max -27 dBV
  • Min +16 dBV

Un-Balanced 1/4” TS Mic/Line

  • Max -27 dBV
  • Min +16 dBV

Un-Balanced 1/4” TS Guitar

  • Max -38 dBV
  • Min +4.5 dBV


  • 2 x 1/4″ Balanced TRS Main
  • 1/4″ TRS Headphone
  • Individual level controls


  • RCA Composite (requires compatible apps)


  • MIDI In (DIN)
  • MIDI Out (DIN)
  • 1/4″ Footswitch (function assigned by apps)


The iO Dock power supply is 6 VAC 3.0A.  It is a universal power supply rated for 100-240 VAC 50/60HZ 0.8A

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