How to Setup a Mix Minus for Recording Skype

Want to record Skype calls for your podcast interviews? This is how you do it.

Scroll down to see a complete photo walkthrough and description of the steps demonstrated in this video.

 

Recording a Skype conversation or any other VOIP program on your computer using professional (XLR) microphones with the ability to mix in other sounds all without having the person on Skype get a feedback loop of their own voice, requires you to setup a mix minus with your audio mixer.

The basic concept is you want to mix all your audio inside your mixer which includes you Skype caller then send that audio back out to Skype minus (without) the Skype callers voice.

To do this you need a mixer with Aux sends. This is a specialized output on your mixer that allows you to select which audio sources coming into the mixer get sent back out.

In this video we are using the Aux B (post-fader) to send our microphone and a soundboard with sound effects (FX) back to Skype. Post fader simply means that our Aux send goes through the main channel fader before getting sent out of the Auxiliary port. In this case, we must turn up both the Aux B send fader and the corresponding channel’s main volume fader in order for Skype to hear the audio. If we were using Aux A (pre-fader) then the main channel fader would have no effect on our audio leaving the mixer via the Aux send for each channel we are sending audio out of the Aux A output.

Why would you choose a pre over post fader and vice versa? If you were recording your mix to an audio recorder as seen in this video, we could use Aux A (pre-fader) to send audio to Skype without being affected by each channel’s main fader so that we could use different audio levels to go to Skype than we are sending to our recording.

Using Aux B (post-fader) would allow us to easily control what level of audio Skype gets by simply adjusting the main channel fader.

In this video the setup is as follows:

  • My microphone (Heil PR40) is plugged into channel 1 via XLR cable.
  • My iPhone is plugged into channel 5/6 via a stereo 3.5mm to Y cable (1/4″ left and right) for sending sound FX into the mixer.
  • My computer (Skype) is plugged into channel 7/8 coming from my computer’s headphone output using another stereo 3.5mm to Y cable.
  • The mixer is sending audio to the computer (Skype) via Aux B using a 1/4″ to 3.5mm stereo cable.

To achieve the mix-minus setup, the Aux B fader on my microphone’s channel as well as my iPhone’s channel is turned up (set your fader at whatever level is good for Skype. I like my Skype audio meter to hit about 70 to 75%).

The Aux B fader on my computers channel (7/8) is left in the off position or turned all the way down so that no audio is going out of the aux send. This is the minus part of your mix-minus. All the audio in the mix is going out to Skype through the Aux sends, minus the Skype caller’s audio on 7/8. If we had this Aux send turned up then the person on Skype would hear their own voice back because we would be sending it back to them after it came into the mixer.

In this video’s setup, each channel that we are sending audio out of the Aux B must also have its main channel fader turned up as well or else the audio won’t leave through the Aux because we are using a post-fader.

It’s much more complex sounding that it really is. Take your time and walk through each step. Skype has a test calling service in your contact list that will allow you to make a call and receive audio back so that you can test your setup.

Step by Step Mix-Minus Walkthrough with Photos

 

****KEYRed Arrows = cable, Yellow Box = mixer input, Blue Box = Mixer Controls****

 

Step 1 – Mixer Requirements and Cabling

For a proper mix-minus setup you need a mixer with an “Auxiliary (Aux) Send” (yellow box in image). This channel allows you to choose which individual channels get sent out of your mixer (blue boxes in image). For a mix-minus, we’ll be sending all of our audio in our mix, minus the channel that has Skype on it.

Step 1 Mixer with Aux Send

The yellow box in this first image (above) shows you where the AUX SENDS are located on my particular mixer. You see that this mixer has two (A (pre), B (post)). Your mixer needs at least one Auxiliary send in order to properly setup a mix-minus. The more Aux’s you have the more separate instances of Skype you can include in your mix.

It’s important to note that many mixers label the Auxiliary Send channel differently. For example, my Mackie ProFX12 labels them as Mon (monitor) Send and FX Send. Depending on what mixer you are using, they may be called something else but a quick check at the specs should tell you how many Aux Sends your mixer or the one you plan to buy has.

In the blue box you see the controls for the Aux Send channels for each individual channel on this mixer. This is where you will set the amount of volume that comes out of the Aux Send channel for each channel on your mixer including sending NO audio (level all the way down/off) on the channel that has Skype coming into the mixer. Remember, this is called a mix-minus because you are sending the “mix” of all your audio coming into the mixer back out to Skype, “minus” the Skype audio. This prevents the person on Skype hearing their own voice back causing a feedback loop. I’ll explain later why you might want to use a “pre” or “post” fader which on this mixer is labeled Aux A and B.

Cabling – Mike Phillips (@McPhillips) wrote an excellent article on choosing the best cables for setting up a mix-minus with your computer. The cables recommended by Mike can be seen in the following images. The cables you see in the video above are fine but as Mike points out, anytime you use a adapter (i.e. 1/8″ to 1/4″) you create another point of potential failure. I’ve never had any issue with the cabling you see in the video but why not start with the best and take Mike’s (expert) advice when it comes to selecting the proper cables.

Cables you’ll see in this walkthrough

 

Step 2 – Plug in the Microphone(s) and Get Initial Levels

Step 2 - Plug in Mic and Set an Initial Level

Here you see I’ve plugged in my microphone (Heil PR40) to channel 1 using an XLR cable. I’ve turned the gain knob (first blue box below the mic input on the mixer) to its center position and the fader for channel 1 (lowest blue box on channel 1) to the center as well. I’ve also turned the fader for the “Main Mix” (blue box on far right, bottom) to the middle position. This knob controls the overall level of all the audio that is feeding into the mixer. These levels are just an initial setting to make sure I’m getting audio from the microphone into the mixer. Simply talk into the mic and see if you are registering levels on your mixer’s LED audio meter.

If you have more than one microphone, repeat this step as outlined above. You can see on this mixer I can plug in three more XLR microphones.

 Step 3 Plug in Aux Send Cable to Mixer and Computer Input

Step 3 - Plug Aux Send into the Computer

 

The next step is to take a cable out of your mixer’s auxiliary send channel and plug that into your computer. This will be how Skype will receive the audio coming from your mixer.

In the picture above you see the red arrow points to the type of cable you want to use. Referring to Mike’s article on cabling for a mix-minus it’s important to note:

Most Internet broadcasters and podcasters are (or should be) using an auxiliary send on the mixer to send a mix-minus feed to Skype. That feed is mono. Most desktop and USB computer sound cards have stereo inputs. Skype really only looks at the left channel for its input, but some cheap, no-name sound cards may actually get the channels reversed internally. Therefore, it’s a good idea to feed to audio from the aux send on the mixer to both the left and right channels of the computer sound card.

A good solution is to use the Hosa CMP-105 cable, pictured here. The CMP-105 has a 1/8 inch TRS plug on one end and a ¼ inch TS plug on the other. The tip of the ¼ inch plug is connected to the tip and ring of the 1/8 inch TRS plug. The ¼ inch mono plug connects to the mixer’s aux out jack, and the 1/8 inch plug connects to the computer sound card. Even though Skype is mono and only sees the left channel of the audio input, the CMP-105 causes audio to appear on both the left and right inputs of the computer sound card.

In this setup, I’m using the Aux B or Post Fader on the mixer to send audio to the computer. See the “advanced settings” section below for reasons why you might want to use either Aux A (pre) or Aux B (post).

Next you’ll notice that the input to the computer is being handed by a device called an “iMic” made by Griffin. This is an analog to digital converter which takes the 3.5mm input (seen here plugged into the “in”) and converts it to a digital signal which is taken into the computer via USB.

If your computer doesn’t have a 3.5mm microphone input (e.g. Apple Macbook Pro models later than 2011) then you’ll need a device like this to input your audio to the computer from the mixer. When you setup your Skype audio preferences, you’ll want to select this device as your “microphone input.”

Step 4 – Plug the (Skype) Computer into the Mixer 

Output from Computer to Mixer

Step 5 (optional) – Plug in a Soundboard or Additional Audio to the Mixer

Soundboard to Mixer

 

If you have another source of audio such as a soundboard with music and effects, listener feedback, or any audio from another computer/device, then you can use one of your remaining open channels to bring in those sounds. In the picture above you see I’ve inputed an iPhone using a CMP-159 ?” stereo to ¼” dual mono cable. I’m using one of my remaining stereo channels because the app I’m using as a soundboard (Bossjock for iOS) will be bringing in stereo audio such as music and sound FX. If you are bringing in a mono source such as voice, you can use one of your remaining mono inputs (1/4″ plugs below the XLR inputs) and only plug the left channel ¼” mono plug (gray lead labeled “Tip”) into the mixer.

You can see I once again set an initial level (blue box on channel 5/6) to confirm I’m receiving audio from the iPhone.

Step 6 Plug in an Audio Recorder to the Mixer

Step 6 plug in audio recorder

 

Finally, we get to the final step in this setup which is plugging in an audio recorder so we can record our Skype call/podcast. Check the “alternative setups” section below to see how you would wire this setup if you wanted to record into your computer. If you do chose to record into a computer, I still strongly suggest getting an audio recorder to record into as a backup. This way if your recording software or computer crashes, you won’t lose your interview. It can be really painful to be 20, 30, 60 minutes into an interview only to lose it because your software decided to crash.

In the picture above I’m using a 1/8″ stereo plug to dual RCA and outputting the mixer’s audio through the “Tape Out” output. This will capture a recording of all the audio going into your mixer including the person on Skype.

Alternative Setups

Record to separate channels

Advanced-panning_channels

If you have a mixer that has either a FireWire or USB2.0 or higher output, you can record all the channels your mixer provides on separate tracks inside audio recording software that supports it. However, most mixers do not have these types of connections. When you only have a stereo mix out of your mixer how do you record audio on separate channels? Panning.

It’s important to understand here that because you don’t have FireWire or USB2.0, you can only achieve two separate channels. However for many podcasters this will be enough because it’s just you, the interviewer and Skype, the interviewee.

You’ll notice in the image above that channel 1 and channel 7/8 have their “pan” knobs turned all the way left and right respectively. Because you are sending a stereo mix (2 channels on a single track) to your audio recording software, you can create two separate channels with the left side of the stereo track containing audio that you panned to the left and the right side containing all the audio you panned to the right.

For example, in the above image, my microphone on channel one will be on the left side of the stereo track and the Skype caller on channel 7/8 will be on the right side of the stereo track. The resulting audio file will look something like this:

Once you begin to edit your audio, you can break apart this stereo track creating two separate mono tracks each containing only the audio that was placed on each track as a result of using the pan knobs. Now I have much more control over my audio in the editing process because my Skype caller’s voice is not mixed with my own.

Some examples of what this allows you to do in the edit:

  • Apply different effects to each audio track – Each person’s voice will be different from the other. When adding effects such as EQ, Compression, Gates, Denoisers, etc. you’ll want each person to have their own unique recipe of effects. By having yourself on one track and you Skype caller on the other, you can handle how each track is processed separately.
  • Remove unwanted sounds – Your interviewee might cough while you’re talking and you’ll want to remove that. Having them on their own track will allow you to remove any part of their audio without affecting your own. If you recorded a stereo mix with panning your two channels, that cough could not be removed without also removing your own audio.
  • Creating cleaner audio – My audio editing workflow consists of removing the parts of an audio track where there is no talking. For example, if I’m asking a question and the interviewee is just listening, I remove that part of their audio. This also removes the noise floor (hiss) from their track thus making the overall mix cleaner. There are other ways to accomplish this such as inserting silence or using noise gates but for me this is the most effective workflow.
  • Fix crosstalk – If your guest speaks at the same time as you are speaking it can cause both or one of the person’s audio to get lost in the crosstalk. This always seems to be the case just as someone has made their most important point. Having each person on their own track allows you to shift the two pieces of audio on the timeline thus allowing each person to be heard. This is an incredibility powerful tool to have as an editor.

Recording into the same computer that’s running Skype – if you want or need to record your audio back into the same computer you are using for Skype, simply run another feed out of your mixer to your audio recording software.

So for example, you can take the Main Mix out of the mixer and input that into your computer (using a separate soundcard/input on your computer) and use that feed to record into software on the same computer. This feed will contain all the audio including the Skype callers voice.

Recording with two computers – coming soon

Advanced settings

Pre vs Post Fader - coming soon

*Gear used to make this video:

*all links should be considered affiliates. Purchases made using these links help support this website. Please read my ethics statement at http://thepodcastersstudio.com/ethics

 

 

 

About Ray Ortega

Host of The Podcasters' Studio, Podcast Quick Tips and Podcasters' Roundtable.
I'm a hobbyist podcaster turned professional. I produce podcasts full time for a large non-profit and teach others how to podcast in my spare time. Living the dream.

Comments

  1. Ray,

    Great Video! Thank you! It looks like I may have a little tweaking to do. Our Skype calls have been "ok" , but levels have been an issue and I think it's because I am not using sends from my mixer properly. I use an external M-Audio Firewire interface box that takes the analog audio from my yamaha audio mixer and "Sends" it to my HP computer via a firewire cable.

    However, the issue for me is getting proper Skype audio levels BACK to the mixer for a full mix for recording and broadcast streaming. Right now, somehow, the same firewire cable that connects the M-Audio box to the computer is ALSO bringing the audio BACK from Skype to the M-audio box. So i'm getting audio in dual directions over the one firewire cable. I'm not sure how or why that is happening, or if that is a normal connection.

    I then have to use the Headphone jack on the M-audio box to send the audio to another input on my audio mixer so that all hosts are hearing the audio from Skype. But I can't raise the audio level very high because of feedback. Then I monitor the entire mix using the headphone jack on the audio mixer itself. So obviously none of this is optimal. The issue I am having is that if the input in my mixer for Skype is too high, we get some weird feedback.

    In your video, you are using sends from your audio mixer to a Mac via a USB interface. So I need to re-think everything I believe because I am almost doing the same thing (I thought) with this firewire box, but the results are not the same. I think my problem is that I don't fully understand how firewire or USB interfaces work. I am a old analog guy, and I understand wires and input and outputs.

    Can you point me to good tutorials that explain how devices like these work? Your video does a great job explaining how to "Wire" your mixer, but it doesn't explain the role of the USB interface in this example. Also, the Mixer you are using is a firewire Mixer, but I didn't understand how it is connected to your Mac. That might be something to cover in future videos as well. Thats what I personally really need to understand better. Digital Audio Interfaces.

    Thanks!

    Mike

    • Thanks Michael. Take the firewire box out of the equation and just hook up the mixe minus the way I do it in this video. The little audio interface you see, the Griifen iMic, is only used if you don't already have an analog (3.5mm) input on your computer. That is how I explained it in the video. Check it out again. I show both of these methods just depending on which option you have.

      The mixer you see in the video is not using the firewire function. I never plug that in in the video. The only part that is important is the part I point out in the beginning which is the Aux send. You need that to do a mix minus.

      Soon I will put together a complete wiring diagram that puts everything you see in the video into text and images which should help. In the meantime, try hooking up your mixer with only analog connections. Aux send to computer's mic input and the computer's headphone output into a channel on your mixer. Let me know how it goes.

      Thanks!

  2. Awesome post. Truly awesome. I have one question though; how can I do a three way skype interview and get each voice on a separate track. I can see how using pan enables you to split an audio file into mono channels in the DAW. But what if there are two callers?

    • Thanks Jon. You\’re probably looking at a mixer that can send multitrack like the Alesis USB2.0 on my gear page or a firewire mixer. I haven\’t played around with multiple soundcards into one machine but if you had more than one that you could input to then perhaps your DAW could take each one as an input.

    • Hi Jon, did you ever get this figured out? You would need a separate computer for each person on Skype. Fortunately most mixers with an Aux have two Aux's.

  3. Gami Rosd says:

    - We are doing a lot of Skype and maximum 4 users plus me so 5 users at the same time doing mix minus, I mean the host is the 1st Skype on a laptop and another 4 guests on another 4 laptop (this is the maximum) running a Skype for each computer or laptop.

    – So number of aux or send and return or receive are very important unless I am mistaken.

    – Please may you tell the exact number of aux and send or return I need for my setup? so when I search for a mixer I can figure out exactly the number of inputs and outputs or aux and send or return that should be included or exist in the mixer.

    • Hi Gami, you need an Aux send for every instance of Skype you are going to want to bring into and out of the mixer. So in your case, if you have 4 people on separate computers/Skype instances each person/laptop will need it's own Aux channel. This is tough because most mixers that are affordable have two. There are however ones with 4 but after that it gets REALLY expensive. This is one of the most interesting new mixers I've seen lately and it has 4 Aux's. Unfortunately I haven't been able to demo it yet to hear how good or not good it is but it might be worth looking into. This mixer does lots of cool things and that is (believe it or not) a good price for what you get http://www.bhphotovideo.com/c/product/790537-REG/

  4. Chris Smith/Out Of Chicago says:

    Dude. This must have taken a lot of hours to put together! Thank you for the help. I think I'm a mix minus master now. :)

    • PodcastHelper says:

      Thanks Chris! Yes, this tutorial probably tops my most time consuming to date. Appreciate the feedback and so glad that this helped you understand a mix-minus and not make you more confused;)

  5. Amazing tutorial. Thank you so much. One question my cohosts are still having a issue hearing my sounds does the single computer setup allow for system sounds to be played for the Skype caller?

  6. Thanks so much for this tutorial! I just finished recording my first interview on Skype with the mix-minus. It's so nice to be able to hear myself while recording. (Before I used two computers, recorded Skype on one, and myself through the mixer on the other.)

    I understand that I can record myself in the left channel, and my interviewee in the right channel (or vice versa), but I was wondering if it's possible to use two computers, record myself with one, record the interviewee with the other, but have them both connected to my mixer in such a way that the interviewee hears me through my studio mic, and I can hear myself and the interviewee. I am using a Behringer Xenyx X1204USB mixer. I figure there must be a way to do it, but I haven't yet been able to figure out how.

    Thanks for any light you can shed, and thanks again for this phenomenal tutorial! It's so great that you have the video AND the text walk-through with pictures. So very helpful!

  7. Hi Ray. No I didn't figure it out. I tried using the other Auxiliary Send to send to the other computer, but I must've done something wrong because there was a LOT of noise in the audio. I'd really like to figure this out, because with my set-up I have to use 2 computers if I'm going to use a mix-minus while recording with Skype.

    • Lex, why not just use a single computer with the panning method? Otherwise you would need more Aux outs. You would use the other Aux out on the channel (on the mixer) that is receiving Skype. Aux 1 sends your audio only back to them and Aux two sends their audio back to one computer with recording software. For your own voice on another computer you would need to send that out via another Aux. A mixer with 4 Aux sends starts to get pricey.

      An interesting "hack" to try might be sending the Skype audio out of one computer via a splitter with one lead going into your mixer for a mix-minus and the other lead going into the input on another computer to record. That would only contain the Skype person. Then you could record only your voice on the other computer.

      This one gets pretty tricky cause you're trying to separate so many things. You could probably also hook something up with virtual cables like Soundflower to route some of the audio internally for recording.

  8. The reason I was trying to figure this out is that I'm recording gaming sessions that are 4 hours long, and it gets annoying only hearing myself in one ear. I also would prefer my players to only hear me in one ear. :) I would also like to have a back-up recording of everything in case someone has a problem with their audio (I'm effectively doing a double-ender with 5 people).

    Is there a way to use the panning method, but have the callers hear stereo audio?

    My mixer (Behringer Xenyx X1204USB) has a USB out, which gets a cleaner sound than using the analog mic ins. I was hoping to figure out a way to record everyone in the call, including myself, on one computer using the USB out (and maybe use the panning method so I can split myself and the Skype call into two tracks) and record the Skype call minus myself on the other computer.

    In the past I've done two-person interviews using two computers (one records the Skype call minus myself, the other records myself through the mixer). I'd like to go to a mix minus so the caller hears my studio mic. I'm also using a headset mic pluged into the Skype computer (that's what the caller hears) and I'm using my studio mic plugged into my mixer and the other computer, and I'm worried that the two mics may cause noise(?).

    My mixer only has two auxiliary sends (one pre-fader, and one pre- or post-fader) so this may just not be possible if I can't figure out a way to make it work with the USB.

  9. Jan Mueller says:

    Thank you very much for this post ! Just what I needed.

    Quick but possibly not so simple question. If I have multiple guests calling in via Skype or Google Hangout, can I still use just the one mix-minus with my mixer?

    Also, it seems some people use a compressor-limiter-gate unit to enhance the sound coming via Skype from callers who may have variable quality microphones and speaking practices on their end. Where does that go in the chain?

    I would be glad to arrange for a paid consultation if that is the appropriate way to figure out the set-up I need.

    Thanks much, Jan

    • Thanks Jan, yes if the people calling in are coming from the same source (same Skype session or G+ Hangout) you can use one mix-minus to send back. You are essentially hearing everything on that Skype call and everyone on that one call is hearing you only, they are hearing each other via the conference call that Skype is doing.

      An effects unit like a compressor/limiter/gate gets plugged into your mixer via Insert channels and the audio goes into the mixer, passes through the unit and then comes back into the mixer and out of the output. Feel free to get in touch via the contact page here if you'd like to work together.

  10. Awesome tutorials Ray – they make the whole "mix minus" setup easy.

    Thanks for sharing.

    Brent Price
    The Web Marketing Show

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