the main reason is most probably that laptop speakers and HDMI output are two different sound devices (aka. sound-cards); and JACK can only handle and take over one sound device at a time.
that is not that you're doing anything wrong, or a nasty system problem. It's just that it's structural rather fundamental way of working with JACK and ALSA on Linux systems.
hhere are a few several ways to overcome this kind of restriction and all them involves a significant lot of technical knowledge about JACK-to-ALSA bridges, Pulseaudio, etc. Not a subject for the absolute beginner may I say :)
but, if you really want to really want to get start having your "hands dirty", I'll give you a hint: try running from terminal/command line: alsa_out -d hdmi-device-name ... right after JACK is up and running. You have to know the correct hdmi-device-name and other parameters that must be fitted to the HDMI device in particular (eg. number of channels) and to the running JACK instance (eg. same sample-rate) and other. Please take a look that alsa_out --help and read man alsa_out.
of course it also helps (a lot) if you use QjackCtl or Cadence to manage your JACK setup, always.
the main reason is most probably that laptop speakers and HDMI output are two different sound devices (aka. sound-cards); and JACK can only handle and take over one sound device at a time.
that is not that you're doing anything wrong, or a nasty system problem. It's just that it's structural rather fundamental way of working with JACK and ALSA on Linux systems.
hhere are a few several ways to overcome this kind of restriction and all them involves a significant lot of technical knowledge about JACK-to-ALSA bridges, Pulseaudio, etc. Not a subject for the absolute beginner may I say :)
but, if you really want to really want to get start having your "hands dirty", I'll give you a hint: try running from terminal/command line:
alsa_out -dhdmi-device-name...right after JACK is up and running. You have to know the correct hdmi-device-name and other parameters that must be fitted to the HDMI device in particular (eg. number of channels) and to the running JACK instance (eg. same sample-rate) and other. Please take a look thatalsa_out --helpand readman alsa_out.of course it also helps (a lot) if you use QjackCtl or Cadence to manage your JACK setup, always.
hth.
cheers