Newbie confused about insert connections

[caelia]

Hello! First post here, and I am new both to Ardour and to DAWs in general.

I’m trying to understand how to properly connect an insert … I’ve read the section about inserts in the Manual, but that has not made it clear to me.

If you want details on what I am doing: I’m running Ardour with Jack on a Linux laptop. My sound device is a Behringer UMC404HD, and the device I’m trying to use as an insert is a Boss Loop Station RC-3. I have set up one mono recording track in Ardour, and I’m trying to take the sound captured in that track, send it to the insert, then recapture output from the insert on the same track. I think that’s how inserts are supposed to work, isn’t it? In any case, the Loop Station appears to be receiving sound and returning it to Ardour (see below for how I know that), but I can’t hear or record the final output.

BTW, no, I’m not sure this is exactly the setup I want - at this point it’s an experiment - but my intention in setting it up this way is to produce a multitrack recording with live loops generated by the Loop Station, and minimal processing in software. In any case, I will probably want to use inserts at some point, and I think the issue I’m having would apply to any insert.

I know that the UMC404 works - I used it to make a recording in Ardour a few days ago. I know the Loop Station works. I’m not 100% sure the physical connections are correct, because Behringer doesn’t provide specific documentation on how to connect inserts, but I used a Y-cable, with the TRS plug in one of the insert jacks on the UMC404, and the two TS plugs in the mono input and output jacks on the Loop Station.

My best guess is that the problem is the way I am connecting things in Ardour/Jack (BTW, is there any difference between setting up the connections within Ardour or doing it in QJackctl, or is that just a matter of convenience/personal preference?). The attached screenshot shows how I have set up my connections:

There are a couple of things I don’t understand here. First of all, why is insert 2/audio_send 1 in the “Readable Clients” column, and insert 2/audio_return 1 in the “Writable Clients” column. Because doesn’t “send” mean that you SEND the OUTPUT of some Ardour component to the insert device, and “return” mean that the insert device RETURNS a signal to the INPUT of some Ardour component? So, intuitively, the positions of those clients in the connection graph seems opposite to what it should be. But maybe I just misunderstand the meanings of “send” and “return?”

The other strange thing is that, as you can see in the image, I connected the insert to Master, which is probably wrong. However, I did notice that when I play the loop on the Loop Station, I can see corresponding movement on the Master VU meter - that’s why I think the Loop Station is receiving sound as intended. Anway, I think I want to feed the Loop Station back to the “Audio” track, because that’s where I’m going to record, but there is only one input to that track, but I don’t think I should connect to that, because that’s the same port that receives the initial input, so sending the Loop Station output to there would create a feedback loop in the insert, right? I suppose I could add a new input port to the “Audio” track (or should I say bus?), but I don’t know if that is the right thing to do. Seems like that would also produce feedback.

So … very confused here. Please advise!

[drsaamah (Saam R Sany)]

Let’s back up a little bit… Is there a reason you are using Jack? If you start the project with ALSA, we can use Ardour’s connection manager for the insert (just double click the insert in the mixer window’s channel strip for the audio track) and it’s pretty straight forward and easy to understand. Jack’s interface always confused me…

[x42 (Robin Gareus)]

First of all, why is insert 2/audio_send 1 in the “Readable Clients” column, and insert 2/audio_return 1 in the “Writable Clients” column.

It’s from the perspective of the DAW (or JACK).

“insert 2/audio_send 1” provides data from Ardour’s audio track. It’s the source. Audio data can be read from there.

Later the processed signal is returned to Ardour. In other words, it is written back.

In the screenshot that you have posted, the left column are all “sources” and the right column “sinks”.

• A source might be an Ardour Track during playback, an inserts’ send port, or a soundcard’s analog input. A port that that provides data (readable, output)

• A sink could be an Ardour Track’s record input, or a soundcard’s loudspeaker, etc. Data is sent to it (writable, input).

From this perspective, a loudspeaker has inputs (cables send a signal to the loudspeaker, write-only) but is a playback device. – A Microphone has outputs (it provides a signal, read-only), but is a capture device.

[caelia]

Reason I am using Jack? Uh, because I use Jack? Seriously, though … as I said, I haven’t used a DAW before, but I’ve used a variety of other audio programs (or perhaps I should say “played with”), and sometimes I want to interconnect them, so I find that Jack usually enables a sensible workflow, with the fewest special-case operations. And thus I am in the habit of using Jack. But it’s not strictly necessary.

As for using the Ardour connection manager … I think I have used it, in addition to QJackctl. And it looks as though it duplicates the functionality of the QJackctl connection window. And when I see two interfaces that appear to do the same thing, I naturally wonder if they really do exactly the same thing, and if there is any reason, other than convenience and personal preference, to choose one over the other.

But that’s not the real problem. I know how to make connections, regardless of which interface I’m using; the question is what to connect. Thanks, though!

[caelia]

It’s from the perspective of the DAW (or JACK).

“insert 2/audio_send 1” provides data from Ardour’s audio track. It’s the source. Audio data can be read from there.

Well, um, yes … I do understand what sources and sinks are, but this hasn’t yet cleared up my confusion. Maybe these questions will help:

• If “send” is a source, what signal comes from it? And

• If “return” is a sink, what signal should go to it?

From what I see happening in the connection graph, it appears that “return” corresponds to the signal going to the external device, and “send” corresponds to the modified signal coming back from the external device. I don’t see how else it could be. And that labeling of the ports seems backwards. Or maybe my mental model of inserts is just wrong (which could indicate a need for more thorough documentation?).

However, I think the main problem remains to be addressed. What do I do with the signal returned by the insert? I want to be able to hear it and record it in a track, but I don’t see a suitable port to send it to to get that result.

[x42 (Robin Gareus)]

• If “send” is a source, what signal comes from it?

It comes from Ardour’s Track where you’ve added the insert. Connect this to the external effect (usually hardware ports, send signal to the external FX processor’s input)

If “return” is a sink, what signal should go to it?

The processed signal from the external effect is returned to Ardour via that port.

Ardour’s own UI might make this more clear:

[ahms]

https://youtu.be/YUucqDjB2GY?t=513

I think this is what you mean there’s lack of documentation – those connection ports look difficult in understanding, and the narrator on video I think does not a bad job in explaining them. From what I can tell it looks like you can use the playback-inputs and pass that to the usb-data connection. This looks like the most confusing part of the connection port descriptions, so I set the timing of the video around this point to explain what those connections do.

[caelia]

So, just to close this out:

I’ve discovered that the real problem here was that I didn’t fully understand the capabilities (and limitations) of the hardware. When I saw that the interface had inserts, and Ardour had inserts, I incorrectly assumed the two were related. But I found a schematic of the interface circuits, and realized my mistake.

In fact, the inserts on the USB interface are part of the preamp circuits, and are not available to any software. So it is simply not possible to use them the way I was trying to.