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Recording on Different Channels?

Postby audio_jungle » Fri Aug 10, 2018 1:12 am

Can someone help me understand the logic behind recording to different channels?

The context of my question is related to setting up a podcast.

I think I pretty much have System Preferences > Sound, Loopback, Audacity and Zoiper figured out.

Now I need to understand how and why you split things onto different channels.

For instance, let's say on my podcast, I was interviewin someone on the "phone" (i.e. Zoiper) and I wanted to be able to have my voice on one track/channel (?) and the interviewee on another track/channel (?) and maybe some music on another track/channel.

From a sound engineering standpoint, I'm not sure how things should be combined or split.

And from a technical standpoint I have even less of a clue!

Thanks,


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Re: Recording on Different Channels?

Postby ef37a » Fri Aug 10, 2018 5:43 am

I can't help you with podcasting but as far as Audacity is concerned I am pretty sure you can only setup as many channels as the hardware supports? Since most "budget" interfaces and USB mixers are just two channels, your example of three would not be possible.

There are however plenty of affordable AIs around now with 2 mic/line inputs and 2 line inputs. If you need 4 mic ins the monies go up rather steeply.

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Re: Recording on Different Channels?

Postby CS70 » Fri Aug 10, 2018 6:26 am

audio_jungle wrote:Now I need to understand how and why you split things onto different channels.

The why is simple: every channel allow you to decide the volume of the signal it carries ("balance"), and the specific audio treatment for that signal, independently from the others - but all controlled from a single control panel (a "mixer"). That allows you to create a combined ("mixed") audio which can sound far better than if you have everything on once.
You can do that because every channel has a set of controls ("faders") for setting the channel volume, "gain" to adapt the gain to the microphone you use, "eq" to change the timbre, "inserts" to add effects etc) that allow you to manipulate that channel's signal in real time (or in certain cases, automatically).

These controls allow to you to do things like lowering the volume of the music while you or your guest are speaking and raising it up again in breaks, change ("equalize") the voice signal so that it becomes more intelligible without ruining the sound of the music, and so on.

The combined channels form your final ("main") signal - which also can be manipulated (in terms of volume, timbre, effects etc) before being sent to the physical device producing the sound (headphones, speakers, a remote computer etc).

Finally: the main virtual output can be configured to be sent to the physical loudspeakers, or headphones or a recording system or application etc (one or more).

About the "how" - in short, every individual channel corresponds to a cable (physical or virtual) connected to a device that's producing a signal (a microphone, a synth, another computer, you name it).

Once upon a time mixers used to be only physical. Nowadays, computer-based systems employ a virtual mixer (an application on the PC) which can see all physical inputs and outputs you have available, but also offers unlimited virtual inputs/outputs.

Even then, for physical devices (say a microphone or a guitar or a keyboard or an ipod), you need a real cable and someplace (an "input") into the computer where to put it.. that someplace is called "audio interface", which carries one or more inputs on one side and is connected to the computer on the other (via USB, Thunderbolt, etc) and does the job of translating the real-world electric signals into something the computer can understand and pass to the mixer program.

For virtual devices (say a music player running on your pc or a synth also running on your pc, or a internet radio etc) you need a "virtual" cable - basically a configuration that tells the computer to take the output of say your music player and pass it to a channel into the mixer.

Stuff like USB microphones are pretty much the same - the USB cable is a physical cable which carries the signal into the mixer application in the computer.

The net result of all this is a system when you can play or record different signals - from physical or virtual devices - mix them to achieve the balance and timbre you want and then direct the combined output where you need it.
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Re: Recording on Different Channels?

Postby audio_jungle » Sat Aug 11, 2018 6:59 pm

Wow, nice response!

Sorry all if I am asking questions out of order and repeating myself, but I have yet to find a guide that takes me step-by-step through to my end goal, and I'm not sure where this is all going!

@cs70
If I have a choice between a physical audio interface and a virtual one, which should I choose for podcasting.

For right now, I am just trying to get a working solution using a USB headset, Zoiper for calls, and iTunes. I think I have figure out how to use Loopback to let me record from all three of those.

However, ultimately for my podcast, I will want to use an XLR mic for recording myself, Zoiper for calls, and iTunes.

I do have a portable 2 channel AI - I forget what I bought - so I guess I can use that to get my XLR mic into my MacBook.

I was looking at Rogue Amoeba's "Audio Hijack", and I think it would be considered a virtual AI.

Am wondering if I can do fades and all of those things as effectively using software and a trackpad as I could with analog controls on a physical AI.

What do you think?

Also, back to my OP, some more questions on splitting audio...

Since the 1970s, people expect music to be in stereo.

What about human voices?

If I record my own voice for a podcast, should it be on one channel (i.e. mono) or two channels (i.e. stereo)?

If one channel, then should it be on the Left or Right channel?

If I have my voice on one channel, and someone I am interviewing on another channel, then which should go on which channel?

What about music from iTunes? Should that go on one or two channels?

And even if I can figure out hwo to separate things onto their own channels, how do you combine things together in the end?

Does the final mix for my voice on one channel and the guest on another?

Does everything get merged together into one channel or two?

Not understanding all of this.

By the way, what is the difference between a "channel" and a "track"?

Thanks!


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Re: Recording on Different Channels?

Postby desmond » Sat Aug 11, 2018 7:27 pm

audio_jungle wrote:I was looking at Rogue Amoeba's "Audio Hijack", and I think it would be considered a virtual AI.

No, it's not a virtual audio interface, it's an app that can record the output of various applications. It can't route audio between different applications like a virtual AI can.

audio_jungle wrote:If I record my own voice for a podcast, should it be on one channel (i.e. mono) or two channels (i.e. stereo)?

If one channel, then should it be on the Left or Right channel?

A human voice is a mono source, it will always be a mono signal, that you can choose where to position it in an overall stereo (two channel) soundfield.

audio_jungle wrote:If I have my voice on one channel, and someone I am interviewing on another channel, then which should go on which channel?

I recommend you listen to a few other podcasts, and you'll get an idea of what people are doing, and what is useful or annoying to the listener.

I'd recommend some slight separation in stereo files, ie with each listener panned a little way to each side, to help with separation, but don't go too far, and don't put one voice in the left channel and one voice in the right channel - that's borderline unlistenable in headphones.

Remember your output file, a stereo file will be bigger than the equivalent mono one, which may have bandwidth implications. You may be fine serving a mono file, in the end, perhaps. Only you know what your requirements are.

audio_jungle wrote:And even if I can figure out hwo to separate things onto their own channels, how do you combine things together in the end?

That's what "mixing" is. You position and balance your various audio sources within your stereo mix as required.

audio_jungle wrote:Does the final mix for my voice on one channel and the guest on another?

No. See above. Have you ever listened to a podcast that does this?

audio_jungle wrote:Does everything get merged together into one channel or two?

Yes, in general, you want to mix your sources (your various audio channels) into a two-channel stereo mix.

audio_jungle wrote:By the way, what is the difference between a "channel" and a "track"?

Imagine you have four mics (four people talking). You have four channels of audio. You could choose to record each channel to it's own audio track. Or your could create a mix of those four and record them in stereo to two tracks. Generally speaking, when referring to "channels", they are mixer channels, and "tracks" are tape/recorder tracks that you are recording to.

A mixer will allow you to route whatever incoming audio channels, to whatever recording tracks as required. Ultimately, you will end up with a stereo mix, with two tracks (left and right) coming up on two mixer/playback channels (left and right).

Hope that helps a bit...
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Re: Recording on Different Channels?

Postby audio_jungle » Sun Aug 12, 2018 2:51 pm

desmond wrote:
audio_jungle wrote:I was looking at Rogue Amoeba's "Audio Hijack", and I think it would be considered a virtual AI.

No, it's not a virtual audio interface, it's an app that can record the output of various applications. It can't route audio between different applications like a virtual AI can.

Okay. But then I believe Rogoue Amoeba's "Loopback" would classify as a "virtual audio interface", right?

(I know when you add a "device" to Loopback the is a "Channel Mapping" setting, and if you choose "Manual", I believe you can assign the device to different channels. But that is a future chapter in my learning!!)


desmond wrote:
audio_jungle wrote:If I record my own voice for a podcast, should it be on one channel (i.e. mono) or two channels (i.e. stereo)?

If one channel, then should it be on the Left or Right channel?

A human voice is a mono source, it will always be a mono signal, that you can choose where to position it in an overall stereo (two channel) soundfield.

Okay.


desmond wrote:I recommend you listen to a few other podcasts, and you'll get an idea of what people are doing, and what is useful or annoying to the listener.

If I can find the time!


desmond wrote:I'd recommend some slight separation in stereo files, ie with each listener panned a little way to each side, to help with separation, but don't go too far, and don't put one voice in the left channel and one voice in the right channel - that's borderline unlistenable in headphones.

Is there a book (or website reference) that could give me a crash course in this?

Sounds like a fascinating, yet complex topic!


desmond wrote:Remember your output file, a stereo file will be bigger than the equivalent mono one, which may have bandwidth implications. You may be fine serving a mono file, in the end, perhaps. Only you know what your requirements are.

In 2018, I don't think that is an issue for most listeners. (In 1995 with 56k dial-up modems, probably yes...)


desmond wrote:
audio_jungle wrote:And even if I can figure out hwo to separate things onto their own channels, how do you combine things together in the end?

That's what "mixing" is. You position and balance your various audio sources within your stereo mix as required.

Again, are there any books that could give me a crash course in this? (I am fascinated by all of this, but don't have months or years to learn. So something that helps me learn enough to be dangerous in a weekend would be ideal for now!)


desmond wrote:
audio_jungle wrote:Does the final mix for my voice on one channel and the guest on another?

No. See above. Have you ever listened to a podcast that does this?

First, technically I have never listened to a podcast. A true podcast requires you "subscribing" and I am not sure how all of that works yet. (Again, 10,000 things to learn and so precious little time to learn them in!!) :shock:

When I say "podcast" what I am talking more so is just a "radio show", and I have been listening to those for over a decade.

To your above questions - being a layperson - I guess I have never really noticed where sound comes from?! :oops:

Even with music and stereo - being a layperson - I don't think my brain really appreciate what all sound engineers do to add to my experience. That is by definition why I am a layperson!!!

When I think of classic music (e.g. Pink Floyd's "Dark Side of the Moon"), then I guess my brain can better appreciate how stereo and separate tracks can add to the concept of "space and time", but when I listen to NPR-esque shows, I guess I haven't ever really noticed how they separate people talking and other elements.

This is why I want to learn from experts like all of you and start seriously studying all of this.

After this weekend, I am hooked on sound engineering!!! :bouncy:


desmond wrote:
audio_jungle wrote:Does everything get merged together into one channel or two?

Yes, in general, you want to mix your sources (your various audio channels) into a two-channel stereo mix.

Okay.


desmond wrote:
audio_jungle wrote:By the way, what is the difference between a "channel" and a "track"?

Imagine you have four mics (four people talking). You have four channels of audio. You could choose to record each channel to it's own audio track. Or your could create a mix of those four and record them in stereo to two tracks. Generally speaking, when referring to "channels", they are mixer channels, and "tracks" are tape/recorder tracks that you are recording to.

So "channels" are really synonymous with "audio input sources", right?

It seems like "tracks" are basically synonymous with "output sources", right?

And to take that farther, you imply that "tracks" really boil down to your ears and either "left", "right" or "both", correct?

Of course, if that is the case, then what about when I hear musicians talk about how they recorded their classic albums using an "8-track recorder" or a "16-track recorder"?

If your final audio producion had 8 or 16 tracks, how would that add value (or take away from value) to the lisetner's experience when they only have two ears?? :?:


desmond wrote:A mixer will allow you to route whatever incoming audio channels, to whatever recording tracks as required. Ultimately, you will end up with a stereo mix, with two tracks (left and right) coming up on two mixer/playback channels (left and right).

I am thinking that Loopback will do that, but I have so much to learn, and to be honest, while Rogue Amoeba seems to have awesome software for Macs, their documents and support sucks... :thumbdown:


desmond wrote:Hope that helps a bit...

Yes, I am making progress thanks to everyone here at SOS!! :D
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Re: Recording on Different Channels?

Postby desmond » Sun Aug 12, 2018 4:56 pm

audio_jungle wrote:Okay. But then I believe Rogoue Amoeba's "Loopback" would classify as a "virtual audio interface", right?

Yes, it basically does the same thing as Soundflower.

audio_jungle wrote:
desmond wrote:That's what "mixing" is. You position and balance your various audio sources within your stereo mix as required.

Again, are there any books that could give me a crash course in this? (I am fascinated by all of this, but don't have months or years to learn. So something that helps me learn enough to be dangerous in a weekend would be ideal for now!)

I'm sure if you google/youtube "basic audio mixing" or "introduction to mixing" you'll com up with a lot of useful material. SOS's archive's "mixing" topic should also be useful.

Mixing is in one sense not rocket science - you are essentially combining multiple audio sources into one overall piece of audio. But the art in it is where the subtley and complexity lies...

audio_jungle wrote:First, technically I have never listened to a podcast. A true podcast requires you "subscribing" and I am not sure how all of that works yet.

No need to subscribe, you can almost always just click on an episode to download/play/listen to it immediately.

audio_jungle wrote:when I listen to NPR-esque shows, I guess I haven't ever really noticed how they separate people talking and other elements.

Then start noticing! :)

audio_jungle wrote:So "channels" are really synonymous with "audio input sources", right?
It seems like "tracks" are basically synonymous with "output sources", right?

If you have four mics coming in, your have four sources, and thus require four mixer channels to bring them into your mix.
Tracks are where you record. If you recorded each of those sources to it's own track, then you are recording to four tracks, and on playback, you still have all sources isolated and individually controllable. Those four tracks will come back into the mixer (which will require four channels).

However, you could choose (entirely up to you, the engineer, depending on your requirements) to record those four source to one mono track, or two track stereo. But at that point, you're mixing your audio and once recorded, you no longer have individual control over each track (it isn't always necessary, for instance).

Pop music is recorded to multiple tracks to retain as much individual control over each audio recording right up until the final mixdown.

audio_jungle wrote:And to take that farther, you imply that "tracks" really boil down to your ears and either "left", "right" or "both", correct?

Tracks are what is recorded in the recording phase. Mixdown will create a new recording, with all the elements/sources combined ("mixed") into one audio file, usually consisting of 2-channel stereo content.

audio_jungle wrote:Of course, if that is the case, then what about when I hear musicians talk about how they recorded their classic albums using an "8-track recorder" or a "16-track recorder"?

Because they required many tracks to record the sources. If the guitarist wanted to record five different prts, he would need five tracks to record them onto. Once the recordings are complete, all those recorded tracks are combined ("mixed") into a final stereo file, which is what the audience hears.

audio_jungle wrote:If your final audio producion had 8 or 16 tracks, how would that add value (or take away from value) to the lisetner's experience when they only have two ears?? :?:

Th final output is pretty much always a mixed 2-channel stereo file. What formats were used in the making of that final mix is of no real importance to the audience.

audio_jungle wrote:I am thinking that Loopback will do that, but I have so much to learn, and to be honest, while Rogue Amoeba seems to have awesome software for Macs, their documents and support sucks... :thumbdown:

Rogue Ameoba are great, but their support will be limited to the use of their software, not in teaching you or working out for you how to audio engineer a complex project. So you might mean their support doesn't really help you work out how to plan your recording rig, rather than it "sucks", perhaps... I've always found them great, personally...
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Re: Recording on Different Channels?

Postby audio_jungle » Sun Aug 12, 2018 5:10 pm

@desmond,

Lots to cheww on...

desmond wrote:
audio_jungle wrote:I am thinking that Loopback will do that, but I have so much to learn, and to be honest, while Rogue Amoeba seems to have awesome software for Macs, their documents and support sucks... :thumbdown:

Rogue Ameoba are great, but their support will be limited to the use of their software, not in teaching you or working out for you how to audio engineer a complex project. So you might mean their support doesn't really help you work out how to plan your recording rig, rather than it "sucks", perhaps... I've always found them great, personally...

No, I meant what I said.

My experience is their support has a hard time articulating how their software products work, and the fact that they have no documentation on their site says it all.

The group strikes me as "people in the know" that are unwilling to share with people who don't "know".

Not a way to sell software, but whatever...
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Re: Recording on Different Channels?

Postby desmond » Sun Aug 12, 2018 5:26 pm

Ok, but that's not my experience with them, or their products, at all.

I'm not sure what you mean by "no documentation" - the Audio Hijack manual is excellent:

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Re: Recording on Different Channels?

Postby audio_jungle » Sun Aug 12, 2018 6:28 pm

desmond wrote:Ok, but that's not my experience with them, or their products, at all.

My experience with their tech support has been less favorable over the last couple of years.

Particularly that they seem to have pushed me to buy Hijack when what I really need is Loopback.

Just sayin...


desmond wrote:I'm not sure what you mean by "no documentation" - the Audio Hijack manual is excellent:

Image

Where is documentation that I can access for the latest version of Audio Hijack which I believe is v3.3?

Not documentation that I get after buy something I'm not sure if I even need, but documentation to help me decide whether to buy?

Do you have a link, because I haven't seen anything on their website.
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Re: Recording on Different Channels?

Postby desmond » Sun Aug 12, 2018 6:49 pm

audio_jungle wrote:Where is documentation that I can access for the latest version of Audio Hijack which I believe is v3.3?

Not documentation that I get after buy something I'm not sure if I even need, but documentation to help me decide whether to buy?

Do you have a link, because I haven't seen anything on their website.

It's part of the Audio Hijack download - just download it, install and try it out, the manual is in the help menu (in Apple Help format).

https://rogueamoeba.com/audiohijack/ - "Free download" button.

You don't have to buy it to try it. To remove it if you don't want it, just drag the application to the trash.

If you have questions on things you're unsure about, I've been using Audio Hijack for years, and am happy to help you try to decide whether it's something you need or not. You can use the demo version in the meantime to see what it can do for you, but in essence, the key things are covered in the quick intro movie (same page as above.) - AH lets you record from any audio source on your Mac to a file (with or without various processing options.)
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Re: Recording on Different Channels?

Postby audio_jungle » Sun Aug 12, 2018 9:25 pm

desmond wrote:It's part of the Audio Hijack download - just download it, install and try it out, the manual is in the help menu (in Apple Help format).

https://rogueamoeba.com/audiohijack/ - "Free download" button.

You don't have to buy it to try it. To remove it if you don't want it, just drag the application to the trash.

Would be nice if they would just post the documentation on their website and not make people install their trial software first. (I have a new machine and hate muddying it up installing software I might not use.)


desmond wrote:If you have questions on things you're unsure about, I've been using Audio Hijack for years, and am happy to help you try to decide whether it's something you need or not. You can use the demo version in the meantime to see what it can do for you, but in essence, the key things are covered in the quick intro movie (same page as above.) - AH lets you record from any audio source on your Mac to a file (with or without various processing options.)

Thank you for the offer.

Based on earlier comments, it still sounds like mastering Loopback is what I really need, right?

You did say that Audio Hijack is NOT a virtual audio interface, but that Loopback is.

So if I want to be able to split things into different channels and tracks, then it sounds like I need to figure out how to do that in Loopback.

And that is some of my frustration with Rogue Amoeba... Based on a lack of good documentation and support, I have spent an enormous amount of time spinning my wheels trying to figure out how to do what I want and which software to use.

It shouldn't be that difficult - especially on a Macinstosh!!

Personally I would like a nice meaty couple hundred page user's manual where I could really learn how to push things and get a PRO set up.

I'm sure I will get their eventually, but it is taking longer than I want!

By the way, what is your background?

If you are like most on SOS, I assume you have a music and sound engineering background, right?

Do you have any hands on experince with podcasting?

Thanks,

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Re: Recording on Different Channels?

Postby desmond » Sun Aug 12, 2018 10:02 pm

audio_jungle wrote:Would be nice if they would just post the documentation on their website and not make people install their trial software first.

Sure, but the Apple help file format unfortunately doesn't make that easy, so they'd need to also publish (and maintain) the documentation in another format, which probably makes the overhead not worth the effort, especially when it's so easy to install/remove the software.

audio_jungle wrote:Based on earlier comments, it still sounds like mastering Loopback is what I really need, right?
You did say that Audio Hijack is NOT a virtual audio interface, but that Loopback is.

I'm not sure what your requirements are, but if you just want to pipe in a bunch of sources to a DAW, and record there, then yes, Loopback should suffice (I haven't looked at Loopback in depth, but that is basically it's main use case).

However, I would expect that this only works if you are using applications which can set their own audio input and output audio devices. For example, if Skype lets you set it's audio output device, then you set that to your Loopback virtual device, and record from it in your DAW. However, if you have an app that just outputs to the system audio, you may not be able to pipe it's output to your DAW - I'm not sure how Loopback handles these cases, but I can have a look.

Edit: Ok, I had a look, and it looks like Loopback can hijack applications' output using the same technique as AH, which is great - it means any app can be piped into your Loopback device. You should be all set with Loopback.

Have you listed out your requirements anywhere, and the sources and apps you plan on using?
Do you want to record to individual track per source, so you can maximise your editing flexibility, or do you just want to record to a mixed file quickly without needing to edit the raw individual recordings?
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Re: Recording on Different Channels?

Postby CS70 » Sun Aug 12, 2018 10:09 pm

audio_jungle wrote:Wow, nice response!
@cs70
If I have a choice between a physical audio interface and a virtual one, which should I choose for podcasting.

Not sure what you mean with "virtual audio interface" :), an interface is a physical object which connects devices on one side and computer on the other.

If you want to make a "radio show" mixing vocals, pre-recorded music and sound effects (not live) all you need is a microphone for each voice you want to record at the same time, and an interface which allows you to plug in the mics on one side, and get the signals on the computer on the other; and a DAW (digital audio workstation, on mac you have garageband I guess?).

Alternatively you may use USB mics (where the interface is inside the microphone body.. but never tried using many at the same time).

The DAW allows you to record, play back and mix. So you first record your voices (or interview etc) ; then import the music tracks; balance them - voila'.

If you want to do that live, you need pretty much the same setup, except is far easier to balance on the fly with real faders, so you need a real mixer or even better an interface/mixer. You can still use the DAW to record the mixer output (i.e. your programmer) or even the individual signals so that you can alter the balance later.
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Re: Recording on Different Channels?

Postby desmond » Sun Aug 12, 2018 10:13 pm

CS70 wrote:Not sure what you mean with "virtual audio interface"

We've been using them for ages, I first used Soundflower back on PPC Macs... Extremely useful, as you can pipe the output of apps into other apps on the same system.

Loopback does the same thing, though slicker and with a nice hijacking output feature.
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Re: Recording on Different Channels?

Postby desmond » Sun Aug 12, 2018 10:52 pm

Ok, I did a little test to see how Loopback works.

My test goal, have two audio sources, iTunes & Spotify, get sent via Loopback into Logic (my DAW of choice), with the stereo feed of iTunes being recorded to one stereo track, and a stereo feed from Spotify to a separate stereo audio at once.

The procedure:
- Run ITunes & Spotify
- In Loopback, add iTunes and Spotify as audio sources to be piped through Loopback. Tick "Mute audio sources" and untick "Monitor" checkboxes (we'll be monitoring via the DAW).

Now, by default Loopback will mix the audio sources into a stereo (2 channel) mix of all the sources. We do not want this, as I want to be able to record the individual audio feeds to individual tracks in my DAW. So:-

In "Channel Mapping", set this to Manual. At this point, the "Left" and "Right" channels will appear to the right of the sources in the source table. In the Channel Mapping table, hit the "+" icon twice to create two more audio channels (four in total, for our two stereo feeds).

Drag the blue "Left" channel from the iTunes audio source, to the "1 (Left)" output channel, and the "Right" to the "2 (Right)" output channel, and then the same for the Spotify left and right, to channels 3 and 4.

Ok, now, with both apps playing, iTunes is being sent to Loopback channels 1+2, and Spotify to Loopback channels 3+4.

Image

Ok, that's our Loopback config done.

- Run the DAW (Logic here), and choose "Loopback" as the input audio device for Logic.
- Create a stereo track, and set it to Input 1+2 (our iTunes feed).
- Create a stereo track, and set it to Input 3+4 (our Spotify feed).

You can now record/input monitor, and see the two stereo feeds going to the correct track. Works great (this is why virtual audio devices are so useful!)

Ok, so back to the OPs setup. What I would suggest is to add *all* your required audio sources in Loopback, including your mic (or audio interface where your mic is coming in from, depending on your hardware). Then make sure you create as many Loopback channels as necessary to pass all the individual audio feeds you require for each audio source.

Then set Loopback as the audio input device in your DAW, and choose the correct audio input/s for each feed on an appropriate track. Hit record, and you are recording all your individual audio channels into individual tracks in your DAW.
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Re: Recording on Different Channels?

Postby desmond » Sun Aug 12, 2018 11:54 pm

And if you don't want to use a DAW to do the actual recording (or want a secondary backup recording), in this example (following on from the test in the above post), I'm using Audio Hijack to do the recording:

Image

The top line is sending Loopback channels 1+2 (iTunes) to a stereo AIFF file, and the second line is sending Loopback channels 3+4 to a separate stereo AIFF file. Or you can just hijack the output of the individual apps and record directly to their own files.

These files can be loaded into a DAW/whatever for editing later.

You can also using Audio Hijack insert plugins, control levels, send to at internet broadcasting server, and use their Farrago app to feed in sound clips, theme tunes, jingles/stings etc in realtime into your audio - it's all very flexible.

Taking it further:

Image

Here we're dong the same thing, recording the two feeds to their own files. We're also taking those two feeds, increasing the volume of one of them, mixing them together and running a compressor plugin on them, and recording the combined mix as a reference mp3 file, while simultaneously broadcasting this to the internet for a live feed of the recording session (this is now quite common where podcasters broadcast a live feed of the recording that their audience can listen to, before the edited version is released a few days later...) - all in realtime.

I love the Rogue Amoeba apps. Loopback is way nicer than using Soundflower, albeit a little pricey. It's also a somewhat more solid way of creating aggregate audio devices than the system way, for apps like Logic that can only specify one device for audio input... Very cool. :thumbup:
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Re: Recording on Different Channels?

Postby audio_jungle » Mon Aug 13, 2018 2:20 am

desmond wrote:Edit: Ok, I had a look, and it looks like Loopback can hijack applications' output using the same technique as AH, which is great - it means any app can be piped into your Loopback device. You should be all set with Loopback.

Have you listed out your requirements anywhere, and the sources and apps you plan on using?
Do you want to record to individual track per source, so you can maximise your editing flexibility, or do you just want to record to a mixed file quickly without needing to edit the raw individual recordings?

Well, being new to all of this, there are lots of unknown unknowns...

Here is what I have and know so far...

I dropped about $2,000 two years ago on professional mics, a mixer, cables, rigs and a Portabooth. All of this has sat idle since I bought it due to life issues getting in the way.

I have two dynamic and a condenser XLR mics. I have a portable 2 channel audio interface - forget what it is. And some hardware signal "booster" thing. And a nice pair of Sony MDR 7506 headphones.

To record my voice, I will use either the dynamic or condenser mic.

I expect to want to have background music and special effects, so I'll use VLC or iTunes for that.

To interview people by phone, I will use Zoiper.

If I need to interview multiple people or have like a conference call, Zoiper Pro supposedly handles that, but I'm not sure.

Everyone uses Skype, but that seems dirty to me as a Mac user.

I would prefer to use Audacity in the beginning since it is free and I am familiar with it at least as far as basic editing of music I record.

I might upgrade to Hindenburg as I hear it is good for NPR type work.

I think that's it!

For a final product, I want something that sounds like NPR or other similar educational shows.

Seems like this should be fairly easy to achieve, although I can see that hooking up all of the plumbing is a real "audio jungle"! :D

I am willing to do a deep dive on learning proper sound engineering, but I need to get my podcast live in the next few months, so anything or anyone who can help me fast-track things would be a real life-saver!
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Re: Recording on Different Channels?

Postby audio_jungle » Mon Aug 13, 2018 2:29 am

CS70 wrote:If I have a choice between a physical audio interface and a virtual one, which should I choose for podcasting.

Not sure what you mean with "virtual audio interface" :), an interface is a physical object which connects devices on one side and computer on the other.
[/quote]

In the modern world, a lot of people do everything on their computer.

Rogue Amoeba's "Loopback" software appears to be a digital/virtual audio interface/mixer of sorts.


CS70 wrote:If you want to make a "radio show" mixing vocals, pre-recorded music and sound effects (not live) all you need is a microphone for each voice you want to record at the same time, and an interface which allows you to plug in the mics on one side, and get the signals on the computer on the other; and a DAW (digital audio workstation, on mac you have garageband I guess?).

But the problem is that the only audio source I would be capturing from a hardware device would be my own voice.

Music and sound effects would come from my macintosh.

A Guest would be calling me over VoIP and my Zoiper software phone would ring on my Macintosh and so I would be talking to that person (and recording him/her) all through software. (And that is much more complicated than you'd think!!)

Someday I might have a person physically sitting across from me at a desk, but that would be a less common thing.


CS70 wrote:If you want to do that live, you need pretty much the same setup, except is far easier to balance on the fly with real faders, so you need a real mixer or even better an interface/mixer. You can still use the DAW to record the mixer output (i.e. your programmer) or even the individual signals so that you can alter the balance later.

That is what I was asking before...

Just like using a trackpad can be a real pain in the ass, I am finding out that trying to SMOOTHLY grab a control in a software program and smoothly adjust it to create a fade is nearly impossible.

So I was wondering if there was some hardware device - maybe USB driven - which would have knobs and sliders that I could use to adjust software to create smooth fades?

Similar to how a mouse is easier to use than a trackpad for many. And why they now have writing pads where you can take a pen/stylus and simply draw things out similar to how you would on paper, versus using a shaky hand trying to guide your cursor along the way.

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Re: Recording on Different Channels?

Postby audio_jungle » Mon Aug 13, 2018 2:37 am

@desmond,

The weekend is over and it's time for bed. :(

At least I was able to figure out how to set up an IVR this weekend using Zoiper!

Your detailed post about setting up Loopback is exactly what I need help with, but this thread is sort of morphing and I have lots of questions.

Can I create some new threads that are more specific, and we pick up from there?

It sounds like you are the right person to talk to getting help with all of this!!

Thanks,


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