At the Sounding Edge: Using QSynth and QJackCtl

Two strong GUIs for fluidsynth and JACK make Linux audio tasks easier and faster, letting you get straight to the music.
The Final Mix

QSynth and QJackCtl are essential components of my Linux sound studio, and I certainly can't imagine working in X without them. Yes, you can do everything with their host applications at the command prompt. But, these helpful GUIs make the work much easier, which means I get to make music with less hassle in configuring the gear.

These applications are easy to learn and use, and they serve their humble purposes simply and directly, so there's not much to criticize in QSynth or QJackCtl. I'd like to see MIDI activity indicators in QJackCtl, perhaps in the MIDI connections tab, but that's hardly a pressing need.

So how does this little studio sound ? Check out the demos and let me know what you think. Personally, I'm impressed by the power now available to Linux musicians. I hope this article has revealed some of that power to you.


The author wishes to thank Peter Hanappe and all the other developers of fluidsynth for that marvelous software. Vast thanks also to Paul Davis and all JACK developers for one of the finest achievements in open-source audio software. And of course, great thanks to Rui Nuno Capela for his work on QSynth and QJackCtl.


Similis sum folio de quo ludunt venti.


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Latency w. Delta 66 and Fluidsynth?

Martin's picture

What kind of latency do you get from the Delta+Fluidsynth combo? I have a MIDI instrument (Akai EWI 4000s) and I'd like to send MIDI from the EWI to the computer and have it render the sounds. But with my current, (and crappy) onboard soundcard, the latency is simply terrible. I'd like a MIDI-in => audio-out latency of something < 10ms; is that feasible at all?



akai 4000s

velotron's picture


I've been trying to edit the patches on my EWI 4000s from my Debian box with no success. I successfully got the Uniquest software installed under Wine, but can't seem to get it to find the EWI. I configured it with OSS drivers to my emu10k (SB Live) card, but no luck. Any pointers? Thanks!

cant find ewi

Bird's picture

My Uniquest software can't find my ewi too.
Do you know how to solve this?


Anonymous's picture

You forgot to put Hammersound in the Resources. Here is the URL:

Thanks for this article.

In the soundfonts-list (Figur

Anonymous's picture

In the soundfonts-list (Figure 7 - Soundfont Selector)
select a soundfont with right mousebutton and choose edit.
You now can set the offset (wich is the bank number !)
This way you can play different soundfonts on different banks, without
adding another qsynth-engine.

doesn't work in ubuntustudio default install

Anonymous's picture

tried, but that edit button shows up under the mouse cursor, but doesn't work. nothing happens, no dialogs or choices.

Author's reply

Anonymous's picture

Thank you, I didn't realize that's what the Offset label meant.

I'm still learning something new everyday... :)


Dave Phillips

Author's addenda

Anonymous's picture

Two additions:

To select a new synth engine in QSynth click anywhere in the bottom strip of the GUI. You don't have to click on just the qsynth1 tab (see Figure 4).

The Options dialog also includes a selector for a very handy VU meter (not shown in the screenshots, sorry about that). The meter indicates the sum of amplitudes from each engine, making a handy tool for avoiding clipping (i.e. amplitude distortion).

Best regards,

Dave Phillips

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