by Kevin Donnelly
Install LinuxSampler (package linuxsampler) and the frontend Qsampler (package qsampler). Download and unrar (package rar - rar -e rarball.rar) Mats Helgesson's Maestro Concert Grand piano sample from the LinuxSampler site - http://www.linuxsampler.org. It's a 337Mb download, and unrars to 939Mb! Start JACK, and then Qsampler, which will also start LinuxSampler itself.
Go to View -> Instruments and click the New Instrument icon. Browse to the location of the Maestro sample and load it (it will go into Program 1). Close the Instrument dialogue by clicking the x in the corner.
Go to View -> Devices. Click on Audio Devices in the left-hand panel, choose JACK as the driver from the drop-down in the right-hand panel, and then click Create. A new entry, Audio JACK device 0, should appear under Audio Devices. The MIDI Devices entry can be left alone, since it shows only ALSA as the driver.
In QJackCtl, go to the Connections window. In the Audio tab, connect the LinuxSampler entry to alsa_pcm. In the MIDI tab, connect Rosegarden to LinuxSampler. Connect your input keyboard to both Rosegarden and LinuxSampler.
In Rosegarden, select the track to be recorded onto. In the Playback parameters drop-down of the Track Parameters section of the left-hand pane, select the proper entry for LinuxSampler from the Device drop-down. It may be labelled as something like "out 4 - MIDI output system device", but once you have the right one, it will show up as something like "132:0 LinuxSampler: Port 0" in the Instrument Parameters section. Press the red Record button, and play something on the keyboard.