[nzlug] Sound generation on Linux

[Cliff Pratt]

Peter Butler wrote:
> 
>> Say I have a program like 'vkeybd'. This is supposedly a simple 
>> 'virtual keyboard' that supports MIDI. It puts up the keyboard fine, 
>> but no sounds happen when the keys are pressed. Other things like 
>> games produce sounds, no problems. Obviously I'm missing a link 
>> somewhere hence the request for some 'edjikation' on sound matters.
> If it's a midi-only keyboard you need to connect it to a MIDI sound 
> source to produce sound.  Sound sources can either be hardware (e.g. an 
> external synth or sampler, connected to your computer with a MIDI cable) 
> or software (a soft synth or soft sampler that runs on your computer).
> 
> The easiest way to get started is to use a soft synth or soft sampler.  
> One of the easiest soft synths to get started with is ZynAddSubFX.  This 
> comes with a built-in keyboard but you can also connect a virtual or 
> real keyboard to control it.
> 
> To wire all this together, and to ensure all your sound applications 
> play well together I find it easiest to use the Jack low-latency sound 
> daemon (jackd).  You can also install qjackctl, which gives you a nice 
> simple gui to control it.
> 
> A very basic step-by-step guide follows:
> 
> 1. Install jackd, qjackctl and zynaddsubfx (if you are running debian or 
> ubuntu these are available via apt-get or synaptic)
> 2. Run qjackctl and start the sound daemon (before you start the daemon 
> you might have to configure it to use alsa for output)
> 3. Start your virtual keyboard
> 4. Start zynaddsubfx and configure it to use jack for output (it might 
> automatically detect that jack is running and configure itself).
> 5. Use qjackctl to connect the outputs of your MIDI keyboard to the 
> inputs on zynaddsubfx.  There is a MIDI config screen in qjackctl that 
> allows you to do this using drag-and-drop.
> 6. Play music!
> 
> Once you have this basic setup it's possible to do all sorts of crazy 
> stuff.  You can have as many soft synths or soft samplers running as you 
> want (up to the capacity of your machine), and you can also run as many 
> keyboards/MIDI inputs as you want.  My previous setup had MIDI drums and 
> a MIDI keyboard connected to the machine with the drums wired up to a 
> soft sampler and the keyboard connected to zynaddsubfx (for synth 
> sounds).  This worked OK on a P4 with bugger all cache and 768MB RAM.
> 
> Here's an overview of a bunch of soft synths: 
> http://www.linuxjournal.com/article/6320  I also use fluidsynth (with 
> the qsynth front-end) for playing sampled sounds, this works well with 
> jackd and is reasonably easy to use.  One fascinating piece of software 
> that you should also check out is spiralsynthmodular, although I'd 
> better warn you that you may spend whole days fiddling with this, it's 
> very addictive.
> 
Thanks for that. I installed ZynAddSubFX and got sound from the virtual 
keyboard straight away. I didn't (yet) install jackd, so how does that 
work? Thanks for the list of *what* to install. I'm now working on the 
'how to' and 'why' of it all. In other words, although it works, I've no 
idea about the how and why.

Cheers,

Cliff