SOLVED: Ardour reports "Wrong port-type" error and freezes

Installation & Configuration Linux
#1

Here we are again ole luvin’, the economy’s crumbling and the world is just a few steps away from being at war again, dontcha just love it. To make things worse, my beloved and trusted Ardour 8.12 starts to behave strange again, that is, what I percieve as strange, ignorant meatbag that I am.

I’ve been wanting to bring up the issue for some time now. As soon as I import a WAV, particularly drum tracks created with Hydrogen, I get the flashing red point in the right upper corner and the respective notification says:

2026-04-18T10:16:36 [ERROR]: BackendPort::connect (): wrong port-type trying to connect ardour:x-virtual-keyboard and ardour:Monitor/audio_out 1

2026-04-18T10:16:36 [ERROR]: BackendPort::connect (): wrong port-type trying to connect ardour:x-virtual-keyboard and ardour:Monitor/audio_out 2

Before that, I don’t know exactly when it changed, the text used to be something like this:

2025-11-15T08:07:51 [ERROR]: ardour::connect: Invalid Source port: (ardour:XYZ 1/audio_out 1)
2025-11-15T08:07:51 [ERROR]: ardour::connect: Invalid Source port: (ardour:XYZ 1 1 1/audio_out 1)
2025-11-15T08:07:51 [ERROR]: ardour::connect: Invalid Source port: (ardour:XYZ1 1/audio_out 1)
2025-11-15T08:07:51 [ERROR]: ardour::connect: Invalid Source port: (ardour:XYZ 1/audio_out 1)
2025-11-15T08:07:51 [ERROR]: ardour::connect: Invalid Source port: (XYZ/audio_out 1)
2025-11-15T08:07:51 [ERROR]: ardour::connect: Invalid Source port: (ardour:Audio 1/audio_out 2)
2025-11-15T08:07:51 [ERROR]: ardour::connect: Invalid Source port: (ardour:XYZ 1/audio_out 2)

XYZ being a placeholder for the actual filename.

Until today, I simply ignored the red flash and the ERROR message, because Aurdour seemed to work fine and I was too impatient to look into the issue, I just wanted to record music. But by now it seems that the program keeps chewing on the wrong parameters and a loop builds up which eventually becomes too much for the CPU. TOP shows 196% (Dual Core CPU, Debian 11) consumation by the Ardour GUI, and the remaining 4% just allow for changing to the prompt and kill the process. Try that with one of microsoft’s abominations by the way, good luck.

I would be most obliged if somebody would be as kind as to brief me on which parameters to set in order to prevent this from happening, thanks for your attention and your valuable time. I’m on my last leg recording the next song which I’d like to upload in the Made With Ardour department, naturally.

Keep on rockin’ in the free world!

Sincerely,

Fineweather

1 Like
#2

What settings do you use in the Audio/MIDI setup window?

#3

The ones which appeared to be the safest.

Audio Device: Alsa

In - and output device: either the DI or USB Microphone, activated by alsamixer

Sample rate: 48 Khz

Buffer Size: 512 samples, which has been a good compromise between stabilty and low latency so far

#4

Your USB microphone also has outputs?
I am not sure what device you mean by “the DI,” does it have the same number of inputs and outputs as the USB microphone?

#5

DI = Digital Interface, the analogue/digital converter, in my case a Zoom U-22. Connected to the computer via USB plug, like the USB Microphone, as the name says. No further connections.

I am convinced that those two can be ruled out as possible sources for the problem. Ardour never complained about a single track that was recorded with either one of them, they worked A-Ok out of the box from day one. Like I said in my original post, the issue appears to be with imported WAVs.

Anyway, why do you ask, what’s the idea?

#6

I just started Ardour and I get the same message again:

2026-04-19T07:18:09 [ERROR]: BackendPort::connect (): wrong port-type trying to connect ardour:x-virtual-keyboard and ardour:Monitor/audio_out 1
2026-04-19T07:18:09 [ERROR]: BackendPort::connect (): wrong port-type trying to connect ardour:x-virtual-keyboard and ardour:Monitor/audio_out 2

This is something new I’m certain. Never had that before.

#7

In ardour terminology “Backend” refers to the module which interfaces between the Ardour audio processing and the system audio hardware or audio server API, on a Linux system either the ALSA driver or a JACK server API.

Audio files do not have any ports, so don’t get hung up on the path you took to get to the error.

Check the monitor output and the virtual keyboard in the audio and MIDI connections Windows. Check all possible destinations and see if something looks incorrect.

The message looks odd because it calls out both a MIDI source and an audio source. I did not think that the connection manager would let you connect incompatible port types, so I’m not sure that whatever connection attempt is being noted will show up there. That is the first place to start, though.

1 Like
#8

Thank you very much for the substantial information. I looked into the connection manager
but to be honest, I don’t even know what I’m looking at 'cause I don’t know how the connections are supposed to work in the first place.

What I noticed though, in fact have been noticing since I started using Ardour, ist that the vast majority of connections isn’t checked. I have always left that alone, because when I once checked a connection I got feedback and that was that. Thus I assume that it’s the default setup I’m looking at.

After connecting the interface or the USB microphone to the computer, my next step always is to start alsamixer and choose the respective hardware, there’s nothing wrong with that, is it?

Thanks again!

DW

#9

Update: I found something in the audio connections manager. Left and right channels of imported Hydrogen drum tracks were reversed from sources to destinations.

I set left and right according to the values which are set by Ardour on all tracks that it generates itself. The flashing red light disappeared and stopped reappearing like it did before but sadly, Ardour keeps freezing.

This is most annoying. Could it be I’d have to look much deeper under the hood? Probably at any configuration files or whatever? Oh Dear…

#10

In general you want one source connected to one destination. Each destination could have multiple sources connected.
As a concrete example the basic project template will connect each track to a stereo master bus, and the master bus outputs will connect to the system audio interface. If you selected ALSA backend then the master bus outputs connect to the audio device outputs. If you selected JACK/Pipewire backend then the master bus outputs connect to the system audio output ports in the JACK server (which is probably pipewire-jack on a recently installed or updated distribution, or might be jackd on an older installation or if you manually picked to install jackd and not pipewire-jack).

Connections can get more complicated from there, for example you could have the monitor section enabled, which will result in the master bus connecting to the monitor controller, and then the monitor controller connects to the system audio outputs.
Auxiliary sends add additional complexity, you could have surround sound, etc. but it appears that you have not intentionally done anything to add complexity, so my starting assumption would be that you have tracks which each have outputs connected to the master bus, and the master bus outputs connect to the system audio output.

No, alsamixer selecting the hardware is appropriate, you may need to verify that the inputs are not muted, that any analog level controls are set appropriately, and that any hardware settings are what you expect (sample rate is usually one you should verify is set to your project sample rate).

That is fairly arbitrary. You may want to intentionally do that sometimes, for example to switch between audience vs. drummer perspective arrangement of drum and cymbal positions.

Just changing which track channel connects to master bus L vs. master bus R should not affect any errors or warnings, although if each track output was connected to multiple destinations that could have caused an alignment warning.

Perhaps screenshots of the audio connections window would help.
It appears from the port names that you are using the monitor section, so the monitor bus outputs will connect to the hardware outputs, the master bus outputs will not connect directly too the system audio outputs.
I usually use hardware for my monitor controller, but I enabled the monitor controller in a session and it appears that when using the monitor controller the master bus outputs do not connect anywhere in the connections manager. I thought the connection from master bus to monitor controller was exposed, but I guess it is an implicit internal connection not visible in the connections manager.

As a start go to the Window menu and open the Log window. Right click and select all, then right click again and select Copy, then paste the entire log contents into a comment here.

You could also attach the .ardour project file to a comment. Those are a little more difficult to read, but perhaps someone will notice something in the connections to explain the errors.

#11

THANK YOU for taking the time to explain, I’m beginning to see the light!

Yep, I’ve been assuming that for some time now, too.
You are right about me using the monitor section btw.

Here’s the log after today’s first freeze:

2026-04-22T08:08:06 [INFO]: Scanning folders for bundled LV2s: /opt/Ardour-8.12.0/lib/LV2
2026-04-22T08:08:07 [INFO]: xjadeo version: 0.8.14
2026-04-22T08:08:08 [INFO]: harvid version: 901
2026-04-22T08:08:09 [INFO]: Loading menus from /opt/Ardour-8.12.0/etc/ardour.menus
2026-04-22T08:08:15 [INFO]: Cannot set I/O Priority for disk read/write thread
2026-04-22T08:08:19 [ERROR]: ardour::connect: Invalid Source port: (ardour:Audio 1/audio_out 1)
2026-04-22T08:08:19 [ERROR]: ardour::connect: Invalid Source port: (ardour:Audio 1/audio_out 2)
2026-04-22T08:08:19 [ERROR]: BackendPort::connect (): wrong port-type trying to connect ardour:x-virtual-keyboard and ardour:Monitor/audio_out 1
2026-04-22T08:08:19 [ERROR]: BackendPort::connect (): wrong port-type trying to connect ardour:x-virtual-keyboard and ardour:Monitor/audio_out 2
2026-04-22T08:08:20 [INFO]: Loading user ui scripts file /home/.config/ardour8/ui_scripts
2026-04-22T08:08:20 [INFO]: Loading plugin order file /home/.config/ardour8/plugin_metadata/plugin_order
2026-04-22T08:08:22 [INFO]: Loading history from /home/foo.history

I replaced the name of the session file with “foo”.
In my understanding, not much information in that log, that is, not about the freeze.

Ardour complains about Invalid Source after import of WAV files
#13

I dove deeper into the filesystem today, hidden files included, and looked for any other log files in .config and /opt/Ardour, but found nothing. The .ardour session file is VAST, I opened it in an editor and scrolled down for hours it seemed… but I think there’s a bit of luck, the information in question appears to be right at the beginning:`

<?xml version="1.0" encoding="UTF-8"?>
<Session version="7003" 
name="One more eff like this and I'll take the tape machine off the shelf!" 
sample-rate="48000" session-range-is-free="0" id-counter="2124314" 
rg-counter="11163" name-counter="1" event-counter="40" vca-counter="1">
  <ProgramVersion created-with="Ardour 8.11" modified-with="Ardour 8.12"/>
  <EngineHints backend="ALSA" input-device="HDA Intel" output-device="HDA Intel"/>
  <MIDIPorts>
    <Port name="Cue Control in" type="midi" direction="Input"/>
    <Port name="MIDI Clock out" type="midi" direction="Output"/>
    <Port name="MMC in" type="midi" direction="Input"/>
    <Port name="MMC out" type="midi" direction="Output"/>
    <Port name="MTC out" type="midi" direction="Output"/>
    <Port name="Scene in" type="midi" direction="Input"/>
    <Port name="Scene out" type="midi" direction="Output"/>
    <Port name="x-virtual-keyboard" type="midi" direction="Output">
      <Connection other="Monitor/audio_out 1"/>
      <Connection other="Monitor/audio_out 2"/>
    </Port>
  </MIDIPorts>

Like you said, perhaps, and hopefully, someone recognises a mismatch, if there is any.

Thanks again Mate, Cheerie-o!

#14

That seems pretty obviously wrong, a MIDI output can connect to a MIDI input, but a MIDI output cannot connect to an audio output.

Try changing that to:
<Port name="x-virtual-keyboard" type="midi" direction="Output" />

Just delete the next three lines (the ones beginning with<Connection and </Port>
Be sure to note that the x-virtual-keyboard port description now must end with the “/” character to mark the end of the connection description, since the previous end marker of </Port> is deleted.

1 Like
#15

Gooood Morning!

I followed your advice to the latter, including typing the slash after “Output”, started the session and voilà: No red dot flashing, no Error message in the log window.

Impatient as I sometimes am, I didn’t copy the session file and edited the copy, but all went well.

I wonder: How did that mismatch make it into the XML file? This is certainly not default configuration, so what can I possibly have done to cause this?

I’ll continue with the session and report back after some time, and if it keeps working without error, which I would anticipate now, I’ll edit the thread title and add SOLVED.

Apart from that, the question remains why ardour complains about wrong port connections everytime I import a WAV. I’ll create a thread on that matter right away.

Thank you again, both for the enlightenment and the advice, you saved the day! And I learned something, which is the best part.

I’d like to express my utmost appreciation of the fact that you don’t read “RTFM” in this forum, at least I haven’t so far. There’s hope for the rest of humanity!

Cheers,

Fineweather

Ardour complains about Invalid Source after import of WAV files
#16

Here’s the latest news:

It has been working without any more hickups for a couple of days now and I think it is safe to say the issue is solved, so I’ll edit the title accordingly. Thank you very much again, you have prevented me from going berserk…! Would it be allright for you if I included you in the video credits and the track description of the song? I want to return something, albeit in a small way, we both won’t become famous…!

There will probably be no video upload by me for some time anyway because I’m about to delete my YouTube channels and Google accounts and move to SUBVERT, which will soon be online. Video uploads are not supported yet but I hope they will be soon.

A-hooga!