How to Make Successful Audio Connections

Hello everyone.
This is a draft of a How-To intended to clarify the use of audio connection tools.

It's intended to prevent us from running into the "self-connection" problem again.

Thanks to the recent forum discussions, I finally understood how the internal flow of the audio architecture is set up...
I've realized that , for example, requests for post-fader sends on the buses are pointless. Those faders were never intended for mixing.

I'm open to suggestions, corrections, and disagreements.
I'd also like to know if you all think it fulfills its purpose, whether it should be published or not.

Rui, I've assumed Qtractor's approach based on my experience and interpretation, but maybe I'm wrong about something. Let me know.

.........

How to Make Successful Audio Connections

Resources cited in the tutorial:

• SEND/RETURNS plugins from the LSP suite: https://lsp-plug.in/?page=download
• Cadence-Render Recorder: https://kx.studio/Applications:Cadence-Render

Qtractor, although it performs the same task as other DAWs and shares the same nomenclature, has its own unique approach.

This can lead to confusion, as we use pre-learned methods from other DAWs that don't fit with Qtractor.
Ninety percent of the time I thought there was a bug in Qtractor, there wasn't. On the contrary.
I simply didn't understand its logic. Once I understood it, I discovered that the flow proposed by Qtractor was more fluid and efficient.

In this tutorial, I'll try to give you an overview of how connections work in Qtractor so you can develop your own audio flows with complete freedom.

1 Connection Areas

When we talk about connections, Qtractor distinguishes between two defined areas.

• Recording and playback connection ports.

• Mixing connections.

2 Recording and playback connection ports

Input and output buses are not intended for mixing. As much as this statement may surprise you, read this section. You'll understand.

In other DAWs, the way to connect to a recording and playback device is through a form called "Devices" or similar.
In these DAWs, the concept of a port may not even appear.

In Qtractor, no such form exists. The connection ports to external devices are the input and output buses.
Connections are managed from the "Connections" window.
This causes a lot of confusion, especially for people coming from other operating systems.
The first thing they do is look for the "Devices" form, and of course, they can't find it.

However, the approach in Qtractor is much more powerful. You can create as many input and output ports as you want for different purposes.
For example, you can create an input bus:

• Mono for vocals with its plugin chain ready to record the already processed vocals.
• Another stereo for guitars with its own effects chain.
• Another stereo for general purposes.
• Etc., etc., etc.

You open it and start recording with everything already configured. I don't know if other DAWs offer this feature. I know there are DAWs that can do it by track, but not generally by groups.

Groups. Here's another difference. In Qtractor, tracks are hosted by buses (groups). There can't be independent tracks. In fact, input buses are all recording groups. The "default" bus in Qtractor (pre-named "Mater") is actually a group that hosts new tracks by default and assigns inputs and outputs to them when they are created. Output buses can serve as group buses, auxiliary buses, mix buses, or master buses depending on how they are used.

They don't even have to be configured in any specific way.

It's that simple and logical:

• If they host tracks, they serve as "Group."
• If they don't host tracks and receive parallel signals, they serve as "Auxiliary Buses."
• If they don't host tracks and concentrate all the mix signals, they serve as "Mix Buses."
• If it's the bus that connects to the end of the audio chain, concentrates all the mix signals, and is connected to an external device intended for playback, it's the "Master Bus."
• Buses can also serve mixed functions.

They are self-defined by their use. Everything is defined because it has its own meaning.

Once users figure this out, they run into another reasonable confusion:
"If I create a bus, and it's duplex and has an input and output... The input bus is the input of the duplex bus where I should connect the signals to be mixed."

In addition to recording, they'll try to use the input bus to mix signals...
No, it doesn't work that way. The input and output ports in Qtractor aren't designed for mixing, only for connecting to external recording and playback devices, whether hardware (a USB microphone) or software (a software synthesizer).

You might be asking: "But aren't output buses designed for mixing either? I don't understand."
My answer: The plugin rack in output buses is designed for mixing. The output ports (including the faders) are not.

You might be asking: "But then what's the point of buses having faders?"
For example, for the Master bus, which is the one that connects to the outside.
And for the others too, but for connecting to devices, not for mixing.

Imagine: You want to collaborate with a friend because he's good at mixing and mastering. However, he works with a different DAW (we all know your friend has his quirks, but we love him just the same). You'll need to freeze/render your groups and aux buses.

That is, you'll need to record your buses to an external device on separate tracks so they can be seamlessly imported into your DAW. You might find the faders useful in this process for adjusting volumes and panning.

Another case: Connecting specific buses to external devices for monitoring purposes. Etc., etc.

They've never lost their purpose. However, they're not necessary for the mixing process.

"But do I need faders on the buses to mix!!!"
Add gain and panning plugins. Those are your faders.

"Are you telling me I can't use the bus outputs for mixing?"
I'm not saying you can't. I'm saying they weren't designed for that purpose.

"What if I try to record the master output to a track to get my master copy?"
Wow! I do it that way too, recording in the session itself. However, it won't work. It's not an external device.

As we've already said, these ports are designed to connect to external devices.

For this specific case, you can do it using send and return plugins.
The SEND and RETURN plugins in the LSP suite do a magnificent job.
https://lsp-plug.in/?page=download

Others prefer to dedicate this task to external recorders (a new instance of Qtractor, Cadence-Render, etc.).

We'll develop the mixing area in the next point.

3 Mixing Connections

The mixing area in Qtractor can be said to include the tracks (including racks and faders) and the plugin racks for the buses.

Qtractor provides us with the following mixing tools:

Direct Connection to the Bus

Logically, each track's output is connected to the bus that hosts it.
Additionally, MIDI tracks and buses can also be joined to groups, as they can host synthesizers with audio outputs.
In this case, the output bus is assigned as follows. Right-click on the plugin rack: Audio > Bus to Select.

AUX SENDS

Aux Sends allow you to send signals from track to bus and from bus to bus. They are pseudo-plugins (internally predefined plugins).
They are accessed by right-clicking on the plugin racks: Inserts > Audio > Aux Sends.

They have one limitation: They don't allow connections between tracks.
For sidechain connections and to simplify connections, it's sometimes useful to interconnect tracks.
Qtractor has never had a tool for this purpose.

In those cases, direct connections between Inserts could be used, which we'll discuss below.
However, this was never their intended purpose, and it was always considered inadvisable to use them this way.
Despite everything, since there was no other way, we used them. In fact, there are even "How to" guides on this wiki that describe their use in this way.

Dangers of use: They may work in Pipewire, but not in Jack2. Or maybe one or the other (or even Qtractor itself) has an update and stops working. They weren't designed for that job. It's that simple.

This can mean that old sessions stop working and need to be rewired.

Fortunately, there are alternatives for this task today. Using inserts to interconnect tracks no longer makes sense.
Once again, the SEND and RETURN plugins in the LSP suite. In addition to simplifying these workflows, they work directly with other plugins in the same suite without the need to set up dedicated connections.

Inserts

If aux sends are used to make dedicated internal connections to the mix, inserts are used to connect the mix to external devices.
That is, you can use external software devices (a synthesizer, etc.) and hardware devices (a compressor, etc.) in real time as if they were internal plugins.

If you directly connect one insert to another, you will create an internal connection, not an external one. Therefore, there's no guarantee that it will work correctly.

4 Conflicting Connections

You guessed right. Anything that involves connecting inserts to each other, buses to each other, or buses and inserts to each other may not work.
This is not recommended. These elements were never designed to be interconnected, but rather to be connected to an external device.

This is precisely the trick. If in specific cases you find it useful to make these connections, but they fail:
Put an external device in between. Don't connect them directly.

I think it doesn't make sense today; there are alternatives...

Although specific situations may always arise in which they are useful, and they happen to work.
But if they fail tomorrow... now you know why.

Of course, freedom above all.