What to Look For in an Audio In / Out Box.

So now that you have read my arguments against USB mics (at least, most USB mics), and you are going on the straight and narrow path of an outboard device to get audio in and out of your computer, the next question is, what do you look for when you are ready to buy?

There are lots of models with all kinds of features on the market, and some are going to fill the needs of a podcaster better than others.  That’s the nature of n industry geared towards the larger market of the musician than the podcaster.  Walk into a music retail chain store, tell the people in the recording department that you are a podcaster, and watch their eyes gloss over (more on that later).  All you need to do is look at a picture of a radio station studio along side a recording studio, and you can see how the needs differ.

But you know that.  What you want are the features to look for, and what they mean.  Here we go.


Direct Monitor:

Direct Monitor

(Alesis io2 Express monitor mix knob)

Direct Monitor allows you to listen to the input of your I/O box directly, without the delay of going through your computer and back.  The processing of audio (analog to digital conversion, software processing, digital to analog conversion) takes time (commonly referred to as latency), and even though that time is measured in milliseconds, it’s enough to sound weird when you listen back.  While most devices provide this function, some do it better than others.  I like having one knob to dial between the direct feed, and the return from the computer. This is especially helpful when recording Skype calls, since your return from the call may be much louder or softer than what you are recording.

Mackie FireWire in section

(Mackie FW In Section)

Having one knob for balance makes your life much easier, but not every manufacturer goes this route. This is the firewire section for the Mackie U.420d mixer, a small format firewire mixer. They don’t make this mixer anymore, and even I’m struggling to find a use for it.  But this isn’t the most intuitive monitor section i’ve ever used.  Keeping it simple will allow you to make quick adjustments to your headphones while you are recording an interview or a show.  Simplicity has it’s place.  I think this is one of those places.


USB or Firewire?

This used to be a more debatable topic, but it doesn’t really matter as much anymore.  Firewire was the champion for more inputs and more stability, but the USB 2.0 spec (and the upcoming USB 3.0) pretty much eliminated the concern.

I use a Firewire device for most of my podcasting (the now discontinued Tascam Fireone), but I am not married to firewire.  The next portable box will most likely be a USB box, but a home mixer will probably be firewire (that’s what the market has that match my needs).

Smaller boxes with two to four inputs are usually USB.  There is no reason not to go USB.  In fact, I would lean towards USB simply because of the way both platforms have evolved.  Look at the connector change in the upgrade of firewire (different connectors for FW400 and FW800), and the way USB has kept the same connector and make it backwards compatible.  The USB plug is going to be around for a long time.  I would hedge my bets in that direction, but you aren’t going to lose anything performance wise going the firewire route.  In other words, it’s a personal preference.


Class Compliant vs. Drivers:

A class compliant device means that it doesn’t need drivers to work.  These boxes are about as plug and play as they get.  I use an Alesis io2 Express at times, and one of the reasons I got it was because it is class compliant.  I like being about to plug it in anywhere, and it simply works.  After trying to get a few other devices working on a friend’s computer, troubleshooting over the phone, and dealing with various driver downloads, I like the simplicity of the io2 Express.

Alesis io2 Express (index cards not included)

(Alesis io2 Express (index cards not included))

If a device isn’t class complaint, that means it will need drivers.  Drivers can provide extra functionality, but you also need to keep up with new releases and upgrades of the drivers.  This isn’t going to be brought to your attention as simply as most software you use.  Drivers rarely alert you to new versions like your word processor or recording software does.  This all sounds negative, but drivers can provide extra functions as well.  Drivers can be worth the bother, if you want what a device has to offer.


Phantom Power (+48v):

Phantom Power

Phantom power is a voltage sent to a microphone through the mic cable.  It is used to power a certain type of microphone (condenser).  Condenser mics are common in all kinds of studios and recording situations.  The other main microphone type (dynamic) does not need phantom power to operate.  There are other microphone types (such as ribbon mics, that can be damaged by sending it phantom power), but the two most common and valuable to the podcaster are condenser and dynamic.

A more detailed discussion of mic types will be coming, and it will be a little more involved than what I should provide in this post.  But if the choice is to have phantom power available or not, get the box with phantom power.  It opens up the choice of microphone you can use.


Those are my primary concerns when buying a simple audio I/O device.  A few other things that may or may not be important to you.

– Hi-Z / Instrument – This is for plugging in a guitar, bass, or other instrument in to your computer directly.  The output of an instrument falls somewhere between a microphone and a line level source (CD player, mp3 player).  Most boxes have this. If you want it, look for it. If not, don’t worry about it.

– Phono in – Turntables have special needs when it comes to interfacing with any audio device.  If you have ever seen a phono preamp, you know what I mean.  Records are produced with a specific audio curve designed to keep the needle on the record.  Phono inputs are tailored for this, but would sound awful with a line source plugged into it.  DJ mixers will have phono inputs.  So will some other devices, but they will be labeled as phono inputs.  Don’t assume that you can plug a turntable into just any input.

– MIDI – MIDI is a spec for electronic instruments to talk to each other.  This can be keyboards, rack synths, effects processors, or even lighting consoles.  MIDI does not transmit audio, but rather data and instructions.  If you don’t use instruments and effects outside of your computer, you don’t need MIDI.  (If you want to get a handle on MIDI, I highly recommend the book, MIDI for the Technophobe, by Paul White)

Pro Tools – Up until recently, if you wanted to use Pro Tools, you had to also have Pro Tools hardware.  This could range from the MBox and M-Audio hardware (and their M-Powered version of Pro Tools) to the full Pro Tools HD hardware.  I don’t use Pro Tools (I prefer Logic Pro), but it’s still a standard.  The latest version of Pro Tools (version 9) allows you to use it with any hardware.  But it is not cheap.


There are more options out there, like USB and Firewire mixers, and boxes with built in controllers, but this everything you would need to create a podcast.   It’s hard to make blanket recommendations, since your needs may be different from mine.  There are devices for every budget, and knowing what your needs are, and how much you have to spend can help guide you as much as knowing what features to look for.   If you have any questions, please feel free to ask.  I’m here to help.



  1. Hi,

    i have a question about the alesis io2 express, the audio outputs, are: 2 one, with ‘alternative’ monitoring, can i use it to DJ with too, i.e. are the two audio outputs separate, one for master and one for cueing, or just the same signal split to two jacks?

    can’t find an answer…. maybe too tired!


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