If you want a whole lot of other open source music software get UbuntuStudio, currently 14.10.

  http://cdimage.ubuntu.com/ubuntustudio/...0/release/

A 32 Gig partition will hold ALL of this, including lots of graphic arts apps that may be of no interest to many musicians..

As far as I know Jack replaces Alsa and reduces latency.

An interesting page is here : http://jackaudio.org/faq/comparing_jack.html

Then with Jack, ALSA still brings the i/o driver.

Hi, thanks for the answers.

What use would it have to use Jack, from what I read about it, it operates on Alsa, and will thus only lead to increased latency?

As far as I know Jack replaces Alsa and reduces latency. You probably need to install the special version of Ubuntu that is designed for music processing.  It uses the XFCE desktop rather than Unity. For what it's worth I use Linux Mint, Mate Edition.  While I can't say for your particular computer, Toshibas have a reputation for not working well with Linux, and generally AMD processors are better performers with Linux than Intel. I'm using an Intel Celeron precently and can attest it's not great, but this particular laptop is an Asus distributed by Micro$oft for only $200.00, which included free shipping to Hawaii.  If you live near a Costco, I'd go there and buy one of their lower priced AMD's if they have one, as Costco has a 90 day return policy, no questions asked.  This might sound weird, but it could be a BIOS issue as the one Toshiba I tried and then return had an extremely weird BIOS.

http://www.forum-pianoteq.com/viewtopic.php?id=3397

http://www.forum-pianoteq.com/viewtopic.php?id=3521

What use would it have to use Jack, from what I read about it, it operates on Alsa, and will thus only lead to increased latency?

An external sound would always be an improvement over the likely low quality built-in sound card.  However, there lots of things to do to optimize performance on a linux machine see: http://wiki.linuxaudio.org/wiki/system_configuration and http://www.libremusicproduction.com/art...arted-jack

Quantenirrwisch uses Tango Studio, so the system is optimized for audio.

Do you use Jack?

I recommand you to use jack with this settings:
Priority: 80
Samples: 64 (for a very natural playing experience)
Frequency: 44100 kHz or 48000
Periods: 2

With this settings, the "on the screen" latency should be 2,67 msec in/out

Then you set the max polyphony (in Pianoteq) at 96 or 128.
In these conditions, you should be able to play the keyboard with the right pedal down and increase the polyphony to reach the max without dropouts (Xruns). This situation gives you a very good security.

I can do that with a 2-core Intel 2,53Mhz laptop and with 4Gb RAM.

If you can't, I think the first thing to do is to buy a good external soundcard. If you still have latency problems, then change your pc.

Before Buying all the Stuff, I plugged the laptop to an old yamaha keyboard, which I just use as a Midi controller (via usb) and downloaded the trial version of Pianoteq. While using it with keyboard, I constantly have a Delay, which I defenitely can notice: When I use the Yamaha Keyboard as Midi Controller while also using it's internal sounds, then the sound of the Keyboard is slightly (and noticable) faster than the Sound that Pianoteq produces.

However,  at Pianoteqs  Performance Section, the Audio Load is never above one third of the maximum, and turning the preferences from average to the lowest possible selections (Internal sample rate of 11025 Hz, using 64 samples, and maximum polyphony of 1) doesn't get me rid of the high latency.

What am I doing wrong, and would an external soundcard fix this issue?