4. IO Devices: Getting sound into the iPad

IO devices for iPhone and iPad have substantially improved in the last year. The introduction of iPhone4 and iPad set mobile recording back somewhat because of the elimination of the stereo analog inputs on the dock connector. Then the iPhone5 changed things again with the Lightening connector. A lot of microphones created for the iPhone, like the wonderful Blue Mikey 2.0, are not compatible with iPhone4 and beyond, or iPad. Its taken a while, but there is now a very good selection of devices that support multiple inputs, different devices, have very good quality and are quite affordable. Most also work with any laptop computer too. Choosing a device depends on what sound sources you are going to be recording, and where you will be capturing the tracks.

The iPad and iPhone have introduced a whole new approach to mobile multi-track recording, making it practical to use mobile platforms for nearly complete music production and distribution. This is fantastic especially for hobbyist and traveling musicians. It is now possible to record tracks at the moment and in context almost anywhere, anytime, enabling the capture of musical ideas that would often have been lost in the past.

But on to IO devices. An important consideration is to maintain portability. You likely have your phone with you all the time. Recording is a bit like photography. The best camera is the one you have with you when you need to take that fantastic picture. So the initial focus on iOS IO devices should be to maintain the mobility of the platform. Otherwise you’re better off using a laptop or desktop DAW system with a multi-channel IO device. They don’t cost that much more, most of us already have one or more computers, DAW software like Reaper is getting much less expensive and more stable and capable, GrageBand for Mac is now free, and there’s a wide range of inexpensive USB and FireWire devices to choose from. But these platforms aren’t that mobile, or easy to use when you are both the performer and the recording engineer.

GarageBand on iOS only allows recording one track at a time in either mono or stereo. This has lots of implications for how you do tracking that will be covered in later posts. But it also has an impact on what IO device you choose. Auria, Cubase and MultiTrack do support recording as many as 24 separate inputs simultaneously using a Tascam US-800 or similar USB audio device, and the camera connection kit. So there are other options. But we’ll focus on the simpler, more mobile devices that are consistent with recording one track at a time.

Most of us will be recording sources such as:

  • Acoustic instruments in either mono or stereo
  • Vocals
  • Electric guitar
  • Bass guitar
  • MIDI keyboards or other tone generator devices

This requires an IO device that can support:

  • Mono and stereo microphone input
  • High-impedance 1/4” guitar input
  • MIDI input
  • Stereo line input

There are devices that support all three of these requirements. But you may find that for mobile recording, it may be useful to use a different input device for microphone, guitar and MIDI in order to keep the devices small, portable, low-power and battery friendly. I’ll start with the simplest, most portable devices, and work up to the more full-featured, covering the pros and cons of each.

Microphone Input

Tuscam provides the iM2 and iM2X stereo mics for iPhone and iPad. This is a really great choice. Both provide mono or stereo recording, the ability to position the microphones to the front or back, have a built-in limiter, support an external gain control, support USB charing while recording, and are very light but with good construction quality. I did some testing of the iM2 mic in comparison with others, including an AT-4047 LDC mic and the iM2 compared very well. Its missing a bit in the low end, but not bad, and that’s not always a bad thing for vocals or acoustic guitar.

However, there are some problems. The first is that both use the 30 pin dock connector and therefore require the 30 pin connector to Lightening adapter to use on iPhone5 and beyond. This isn’t really a problem as it moves the mic a bit further from the device providing more convenient use. Second, the iM2 does not have a headphone monitor output, rather it relies on the headphone jack already on the iOS device. This is a good choice since the jack is already there and we use it constantly. But GarageBand may sometimes get confused about what output device to use. If the headphones are plugged in and you plug in the iM2, the headphones are deactivated. The work around is to plug the iM2 in first, then the headphones, or just unplug the headphones and plug them back in to reset the audio output.  By the way, use caution when recording with earbuds, they tend to leak into the microphone. Its better to use noise isolating, closed back headphones. And don’t use earbuds or headphones with an in-line microphone – this will take priority over any mic plugged into the Lightening connector.

One more thing to watch out for, the current Tascam PCMRecorder app stops recording when the iOS device screen goes to sleep. So you’ll miss content unless you keep the screen alive. These apps should all have options to suspend screen sleep while recording so you can watch input levels and have immediate access to the stop button when recording is completed.

Another option is the Mikey Digital from Blue Microphones. This mic supports automatic gain control has a clipping indicator, and a 3.5mm aux-in jack for recording from stereo devices. Both the iM2 and Mikey Digital have a USB pass-through for charging while recording. This is useful for iPhone since recording with a mic results in high power demand and short battery life. A somewhat more expensive option is the Rode iXY. The iXY supports 24 bit recording which is important for increased dynamic range and typically lower noise. However, GarageBand currently only supports 16 bit recording so you won’t get that advantage unless you use something like Auria.

All of these microphones are small enough to have with you all the time for jam sessions, practice sessions, or those times when you go sit by the water playing guitar and get that great new idea.

Next up are the somewhat larger table-top microphones such as the Apogee Mic or Samson Meteor. These microphones generally have a larger diameter sensor and therefore have better bass response. I have both and they also sound great and compared well with the AT-4047. Both have the advantage that you can plug it directly into the iPad camera connection kit, for a simple mobile platform. Unlike the iM2, the Apogee Mic or Meteor is not physically connected to the iPad or iPhone so there’s more flexibility for mic and iPad positioning while recording. Another benefit is the these mics also work with any computer having a USB input.

The Meteor is mono only, and unfortunately, unlike the Apogee Mic, doesn’t have an external gain control. Until iOS 5, and the GarageBand 1.1 update, the mic was too hot and there was no way to control the mic gain using iOS. The only way to avoid clipping was to move the mic further away which introduces noise into the track and more room effects. GarageBand 1.0, and at this time, all other iOS recording applications have an input gain control, but it only controls the input gain of the iOS device, not the gain in the Meteor mic. GarageBand 1.1 and beyond fixes this. The gain control on the mic input recognizes that the Meteor USB mic has internal gain control and actually adjusts the gain in the mic, not just the gain in the iOS device. You can see the difference by looking at the clipping light on the Meteor mic. With other applications like MultiTrack or Meteor recorder (not related to the Samson Meteor mic), you can turn down the input, but the mic still clips and the sound is still distorted. With GarageBand 1.1, when you turn down the mic input, the gain in the Meteor mic is actually reduced and the mic will no longer clip, same as with Mac OS X. This eliminates the need to have an external gain control on the mic, but requires the apps to support USB mic drivers. Fortunately, since iOS7 these mics now also work with the iPhone since the camera connection kit is now supported by iPhone.

A great option might be the Apogee Mic or the Spark Digital from Blue Microphones. These both have external gain controls which are easier to use than changing the gain in the GarageBand input dialog anyway. Generally the clip light on the mic corresponds to clipping in the app. And the Apogee Mic just sounds fantastic.

Another option, especially useful if you already have good condenser mics is to use something like iRig Pro which supports XLR input with phantom power, as well as a 1/4″ hi-Z input for guitar and a MIDI input. This is a good all-around device that has good quality construction and is very convenient.

One last thing about microphones, for vocals, you need to use a pop filter. The mics don’t generally come with one, so you need to get something separate. Any music store will have something that will fit over the mic and provide some protection. Be sure to use one for all vocals.

Guitar Input

There are two ways to get electric guitar into an iOS device. The simplest and least expensive is through the device’s headphone/microphone jack. Devices like the AmpliTube iRig from IK Multimedia fit into this category. These devices are very susceptible to feedback, are generally quite noisy, and suffer from the 200Hz high-pass filter built into the microphone input jack. I don’t find these devices useful, especially for bass guitar, so I won’t cover them further.

The other class of devices are those that plug into the iOS dock or Lightening connector. Devices like the Apogee Jam and iRig Pro fit into this category. These devices have to have their own analog-to-digital converters and a USB interface, so they require power and can be relatively expensive. But the Apogee Jam works perfectly and is highly recommended. Jam also comes with a separate cable that works with any computer having a USB input. All the popular guitar amp simulator applications including GarageBand, AmpKit+ and JamUp work  with the Apogee Jam. These are all good apps, especially JamUp and the companion app, Bias.

I like the guitar amp simulators that are in GarageBand, but they’re not the best. JamUp is great too. You can easily use JamUp with GarageBand using AudioBus. Hopefully JamUp will support IAA soon.

I also sometimes use a Line6 Pocket POD to get guitar into iOS. You can use this with the Apogee Jam, or any other device that supports guitar or stereo line input. The Pocket POD is based on the original Line6 POD 2.0 tones. These don’t compare with the latest Line6 simulators like the POD HD series, but they do sound better than the amp simulators built into GarageBand. So that’s an option if you have a Pocket POD. The Pocket POD also has a “CD input” so you can plug the output of your phone directly into the POD to play along with tracks from iTunes, or jam against backing tracks using OnSong or SongBook. This is very useful and sounds great.

GarageBand doesn’t currently have a bass amp simulator, so you need to use something external or record direct. It is not uncommon to record bass direct. But unfortunately, GarageBand for iOS also doesn’t yet have track or master EQ, so there’s not much opportunity to adjust the bass tone. You can use an external preamp like a bass SansAmp, but that tends to make the platform more complicated and less mobile. I use a Carvin 5-string electric bass or a Dean fretless acoustic bass guitar (ABG) for bass. Both have active electronics and provide a great sound direct into any device. I also use the bass amps in JamUp if I need one, through AudioBus.

MIDI Input

iOS has introduce CoreMIDI support and there are a number of devices that support it including iRig Pro, iRIG MIDI and Line6 MIDI Mobilizer II. Note that the original MIDI Mobilizer does not support Core MIDI and won’t work with GarageBand. These devices are straight forward, and easy to use. iRIG MIDI has support for MIDI Thru. Both support MIDI 5-pin input and output.

Many modern keyboards support USB output, and these will work directly with the iPhone and iPad using the camera connection kit. For example, the Akai LPK26 USB keyboard plugs directly into the camera connection kit connected to an iPad and requires no external power source. Of course that’s a pretty small keyboard so it may not be adequate for all applications.

Other USB keyboards may require a power source or a USB hub. You can provide such a power source easily by using Velcro to attach a simple powered USB hub to the keyboard, and then connecting the output of the USB hub to the camera connection kit. This has the advantage of supporting more than one device such as the Blue Yeti microphone and the M-Audio KeyRig 49. So I highly recommend getting a keyboard controller that support both USB and MIDI outputs for more flexible connections.

For other sound sources such as tone generators, you’ll need a stereo analog input to a stereo track. Unfortunately there aren’t too many highly mobile options for analog stereo input into iOS devices at this time. The Mikey Digital might be a good option.

All-in-One Solutions

The above solutions are all separate devices, and most are mono. Another approach is the more traditional one or two-channel USB audio devices. There’s a lot to choose from here since the USB audio devices that work with most computers will also work through the camera connection kit. Many require separate power, especially when used with the iPhone. I’ll only cover two that have some unique characteristics: the ART USB Dual Pre, and the Alesis iO Dock. Both of these devices maintain mobility while allowing more flexible input/output options and the ability to use your existing microphones. They are less portable than the options described above, and is boarding on a solution that’s not that different than using a laptop and DAW. But this might be a good intermediate solution especially if you want to use your existing microphones or need stereo input.

The ART USB Dual Pre is a typical 2-channel USB audio device. It has everything you need for mic, guitar and stereo inputs and outputs for iPad and it can have external power, but doesn’t require it. The Dual Pre can be powered directly from the iPad camera connection kit, making it a reasonably mobile platform. The Dual Pre also has a separate preamp built-in that can be powered by an internal 9-volt battery if needed. The Dual Pre has no MIDI input though, so you’ll need to have one of the other solutions describe above if you need MIDI.

The Alesis iO Dock is an a good option for the iPad. It provides all the capabilities you’d expect from a two-channel USB audio/MIDI device in a form factor designed for iPad. I won’t go into all the features and benefits because they are well documented on the Alesis web site and in many great reviews. I have had great success with this device, but it hans’t been trouble free. I find the iO dock sometimes suffers from significant digital noise and has to have its power cycled to clean up the sound. This has resulted in some lost recordings – see the next section on direct monitoring. Another problem is that the iO dock only supports 5-pin MIDI, not USB MIDI. So my small, light-weight USB-only keyboard controllers won’t work with the iO dock.
The iO dock might be ideal if it:

  • Supported battery operation. It has to be connected to an AC power source significantly limiting its mobile capabilities.
  • Provided audio input/output from the USB connector so the same device could be use with a laptop computer for USB audio IO.
  • Supported USB MIDI input, not just 5-pin MIDI connectors
  • Had a mono switch for better direct monitoring during tracking, currently direct monitoring puts the source on only one side.
  • Supported Lightening connector and iPad Air

The Dual Pre works well with GarageBand since it is also limited to 24 bit. Some research may be required to determine what’s best for you. The Roland Duo-Capture EX looks good, but check the reviews before purchasing.

Direct Monitoring

Direct monitoring is the ability to monitor the recording input source directly instead of having to go into GarageBand and back out. Direct monitoring has the advantage of no latency. Latency is the delay you hear between the original sound source, and what is played back in your headphones through the IO device, iPad and software. Latency isn’t as much of an issue as it use to be since IO devices, digital input channels such as USB 2.0, computers and mobile devices are much faster than they use to be. But it can still be an issue, depending on the application.

Of course you can’t use direct monitoring if you need to hear the input as processed by the application, say an electric guitar amp simulator or a MIDI virtual instrument. But you can use direct monitoring for acoustic instruments and vocals.

Direct monitoring is generally preferred because it has no latency, but not always. I have had quite a bit of trouble recording with the Alesis iO dock and the Meteor recorder app. The input often gets distorted or filled with digital noise. To be safe, it may be better to avoid direct monitoring so that you are hearing what’s actually being recorded, not what you hope is being recorded. I had to redo a number of tracks because I used direct monitoring and they didn’t get recorded properly.

Another problem with direct monitoring, at least on the iO dock, is that source is only in one ear. I find that tracking is best done with mono monitoring so you hear the same thing in both ears, and you can more easily notice phasing problems.

Some devices such as the Samson Meteor mic can only support direct monitoring as there is no way to turn off the mic. That’s generally not a problem since you’d expect to always want to do direct monitoring with a mic. But note the potential issue with recording problems noted above. I’ve never see those problems with the Meteor mic though. So maybe its only a problem with the iO dock.

Conclusion

This was an long post, and there are many more options I didn’t cover. But this should be enough to get you started, and to avoid some of the pitfalls I’ve experienced in getting sound into iOS devices. It is truly an exciting time when we can have a full-featured multi-track recording device in our mobile phone.

Now that we can get sound into GarageBand, the next post will cover creating projects and doing the song layout in preparation for recoding that sound.

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