I have a USB mic, USB midi controller, and monitors that use a regular 3.5mm jack connected directly to my computer. I was wondering why people get audio interfaces? Is there something they provide that the above setup doesn't? I'm not connecting any guitars. Just keyboard midi controllers.

Note: I did see a question concerning usb mic on this forum, but I'm asking about a more general setup (mic + midi controller + monitors)

4 Answers 4


I have a USB mic

A USB Mic is basically a mic with an audio interface built in. Of course it's all you need if that mic is the only sound source you need. But what if you do want to record a guitar, or a synthesizer? Or you want to use a specific mic that doesn't have USB? That's one reason to get an audio interface - you can connect anything to it.

and monitors that use a regular 3.5mm jack connected directly to my computer

Internally, that will be connecting to your computer's own internal sound card.

Now, a question - when you are multi-tracking, how do you monitor existing tracks while laying down new ones? Back in the days when I was doing more recording, I think it would be unusual to find a DAW that could record from one soundcard while monitoring through another one, while also doing all the right latency compensation that would lead to your newly-laid track being in time with the others. Can your setup achieve this?

Even if it can, I'm sure it can't do zero-latency direct monitoring - although perhaps with a mic that's not such a problem.

Other reasons that people buy audio interfaces:

  • They often have drivers available that provide lower latency than a computer's internal sound card
  • They may have better audio performance than a computer's internal sound card
  • Many of them provide multiple input and output tracks, which is useful if laying down or mixing multiple tracks at one time.

I have only ever owned one audio interface and it was a Tascam something or other - which I recently sold. This device plugged directly into my computer with a USB. The device had 2 input channels .. and I could either plug in a microphone (3 pin) style cable or a regular 1/4 inch cable.

One of the sides also had Phantom Power which allowed a voltage to head towards my condenser microphone which allowed it to be powered and work! On the audio interface I could control the input volume of each input which meant that I could do some basic 'mixing' whilst recording which Guerrilla Home Recording told me was better because it would free up some 'usage' in the computer, and allow a smoother recording experience.

I could also plug my headphones directly into the audio interface and listen to what I was recording. Doing this into the pc would be crazy (I believe), as there would be latency issues i.e. by the time the computer had processed everything and outputted it to my headphones then there would be a delay.

The audio interface simply plugged into mac / pc and I could use it with any recording software I tried. It was not expensive and allowed me to make good quality recordings. Sometimes I had a problem with the input channel that meant it difficult to get the input right. A light on the device flashes red to tell me I'm being too loud.

Essentially all these things - aside from being a physical and tangible device that you can quickly change things on with dials, which is great - are why I used an audio interface. It allowed me to convert 2 input channels e.g. a cable coming from a guitar and a cable both powering and coming from a condenser microphone, at the same time, into a digital format that the computer could interpret and process - so that a digital recording was possible.

In terms of midi controllers I don't suppose having an audio interface would be very useful if you recording directly. As for monitors coming from your computer they are good at playing out what you have recorded - but I have always found a bit of latency on playing it like a normal amplifier i.e. pressing notes on a keyboard and hearing them play back. Though I think setting this up in another way is quite tricky. If you're recording channels at the same time - or even not at the same time - going through USB might lose some of the experience. The USB mic, etc. like you said is in a way also an audio interface so your question pertains more to the use of terms perhaps! I'm not an expert but I have spent many hundreds of hours recording with audio interface and midi keyboard (which I plugged in directly to the computer and never recorded simultaneously). So people use Audio interfaces when they want various channels coming in that they can easily alter for inputs, and also listen to directly for a smoother experience.

Hope something here helps.

  • thanks for your answer, you also have a good writing style so hope to hear more from you in the future. thing is the usb microphone that I'm using (at2020) has a zero latency 3.5mm audio output in case I need to hear myself, but I usually don't use it, because I just need to hear what I've recorded (for overdubs, playblack, etc). also the midi keyboard has zero latency as far as the audio from my DAW so it's not a problem. but I can understand the convenience if it's a full audio setup such as you described where you're recording both a guitar and voice.
    – user34288
    Oct 21, 2019 at 16:09
  • 1
    I appreciate you were asking a question about your set-up particularly the use of midi. I think there is this tangible aspect to the audio interface.. and sure maybe it's used more for more 'analog' set-ups. In terms of the usb mic I suppose in the end it is doing the same thing as the audio interface. Not sure what type of usb mic you have but the one I have you are kinda just limited to that one mic, but of course there are more mics available which aren't specifically usb ones. Or do you have an XLR that converts to USB. I think the question you asked is interesting.
    – Chris
    Oct 21, 2019 at 17:26
  • It's a usb mic, not an xlr. if you look for "at2020 usb" on amazon you'll see it. I have another mic, it's a shure sm57 which is a more traditional xlr mic. I hook it up to an audio looper that I have though, not to my pc. I just keep seeing people talking about audio interfaces. but it occurred to me after writing my question, that audio interfaces are all about audio inputs, not usb/midi inputs (which is what I'm dealing with). Therefore, I guess there's no need for one. but maybe one day if I hook up a bunch of xlr mics or I have a guitar input then I might consider one.
    – user34288
    Oct 21, 2019 at 19:04

An audio interface is essentially an external sound card.

You'd use it to:

1) record (digitize) - analog signals such as guitar or bass (direct to the interface) or microphone.

2) output - a better quality digital signal (more bits) than the computer provides.

Nice explanation from B&H:


"An audio interface is a piece of hardware that expands and improves the sonic capabilities of a computer.

Some audio interfaces give you the ability to connect professional microphones, instruments and other kinds of signals to a computer, and output a variety of signals as well. In addition to expanding your inputs and outputs, audio interfaces can also greatly improve the sound quality of your computer. Every time you record new audio or listen through speakers and headphones, the audio interface will reproduce a more accurate representation of the sounds. They’re an absolutely essential component in computer-based audio production. They’re used for recording music and podcasts, and in video post production for recording voice-overs and sound design.

Why would I use an audio interface? Audio interfaces are used when more a professional level of audio performance is required from a computer, and when one or more professional microphones, instruments and other kinds of signals need to be routed into or out of a computer."

  1. To be able to use the microphone (or other device) of your choice.
  2. Perhaps for better performance (less latency, better quality AD conversion, etc)

Or maybe there is no reason, it depends on you.

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