[Sound Issue] MIDI Pitch Too High in Ardour on Ubuntu Studio 24.04 (ACE FluidSynth / SF2)

[Sound Issue] MIDI Pitch Too High in Ardour on Ubuntu Studio 24.04 (ACE FluidSynth / SF2)

Issue Summary:
I’m experiencing incorrect pitch when playing MIDI tracks in Ardour using ACE FluidSynth with SF2 soundfonts. The pitch is more than a half-step too high, and sometimes changes during playback.


System Environment:

CPU: Intel i7-13700 (64-bit)

Audio Interface: Roland UA-25 EX (Sample Rate: 48kHz)

Operating System: Ubuntu Studio 24.04

MIDI Plugin: ACE FluidSynth with SF2 (48kHz sampled)

PipeWire: Possibly in use


Audio Settings:

Ubuntu Studio Audio Configuration: 128 samples @ 48kHz

Ardour Project: 128 samples @ 48kHz

JACK Settings: 128 samples @ 48kHz


Symptoms:

MIDI pitch is over a half-step too high.

Sometimes pitch starts correctly but shifts higher during playback.

MDA ePiano plugin plays at correct pitch.

MDA DX10 plugin exhibits the same pitch issue as ACE FluidSynth.


Troubleshooting Steps Tried (None Resolved):

Tested various SF2 soundfonts (both 44.1kHz and 48kHz).

Tried ZynAddSubFX (same pitch issue, even without soundfonts).

Switched Ubuntu Studio Audio Configuration between 128/44100 and 128/48000.

Changed audio interface sample rate between 44.1kHz and 48kHz.

Switched output from USB interface to HDMI audio.


Goal:
I’d like to use Ardour reliably at both 44.1kHz and 48kHz sample rates without pitch issues in MIDI instruments.

Any insights or suggestions would be greatly appreciated!

New information 20250503

On my another PC(i5 6600 , audio interface UA-25, midi keyboard Korg SP-200)
Ardour is working in the right way.

When I put out the SSD and boot it on i7 13700 , it shows the same problem.

Recent information

When I switched the midi keyboard to another keyboard, the problem didn’t happen.

On my Alesis Q49, I must play B flat key and keep the pitch wheel to the highest in order to play the C sound.

And I 've found a similar problem report.

https://forums.scopeusers.com/viewtopic.php?t=36535

So, you just confirmed the issue is with your MIDI keyboard and not an Ubuntu-related issue. There’s nothing that can be done on the Ubuntu end.

Yes !

I tried to use my Alesis Q49 on Windows 11 (Ardour),and found that the same trouble happens.

I’m sorry I shouldn’t have asked this issue here.

I think this problem has resolved.

Thank you so much.