Hi!
Some time ago I discovered, that Konsole KPart, that Yakuake uses, somewhy doesn't emit visual bell when that signal triggered inside tmux (terminal multiplexer, like GNU/screen).

Mostly strange, that bell works fine in Konsole itself, and also in KPart *outside* tmux.

P.S. I've tested with:
$ sleep 2; printf '\007'
and
$ sleep 2; printf '\a'

Reproducible: Always

Steps to Reproduce:
1. Run, for example (!), Yakuake
2. type «printf '\007'» or «printf '\a'»
3. run tmux
4. type bell's printf command once more
Actual Results:  
There is no visual bell inside tmux, but it *is* outside.

Expected Results:  
Bell works inside tmux as well as outside.

1) bell works either inside or outside tmux in Konsole itself, but not in KPart, that Yakuake uses.

2) [cut of my discussion with tmux developers]
2013-07-29 23:46:35     thomas_adam     mva: So get a terminal emulator which respects the bellUrgencyHint, and then you will.  XTerm does, for example.
2013-07-30 02:14:22     mva     thomas_adam: isn't my terminal support bellUrgencyHint, if it detects \a? ;)
2013-07-30 02:25:32     thomas_adam     mva: You said you wanted your terminal to notify you if tmux emits a BEL, yes?  Certain terminal emulators allow for setting the XUrgencyHint when such a thing happens, via an option usually called urgentOnBell; this is what XTerm calls it, other terminal emulators will differ.  If you're then using a decent window manager, then those will pick up on that fact and do something accordingly, such as make the window border red, or popup some ...
2013-07-30 02:29:33     mva     uhm... to be clear: I'm using konsole. It catches shell beeps, "\a" and so on bells pretty fine and can ask window manager to visualise it, or send notify-popup, if tab is inactive. But I can't get it to work with tmux :-/ So, yes, I asking exactly that, but I dunno what should I check :/
2013-07-30 02:33:40     NicM    well
2013-07-30 02:34:42     NicM    my tmux sends bells through by default
2013-07-30 02:34:47     NicM    ie, it works for me
2013-07-30 02:35:06     NicM    sleep 2;printf '\007' inside tmux and it sends a bell
2013-07-30 02:36:35     NicM    if you turn on visual-bell are you seeing the messages?
2013-07-30 02:37:59     mva     NicM: yes
2013-07-30 02:38:46     thomas_adam     Try it in XTerm.
2013-07-30 02:38:55     thomas_adam     I wonder if Konsole is being stupid.
2013-07-30 02:41:06     NicM    well it sounds like something is wrong outside tmux
2013-07-30 02:41:23     thomas_adam     mva: xterm -xrm 'xterm*bellIsUrgent: true'
2013-07-30 02:41:45     thomas_adam     mva: But tmux is doing the right thing---no surprise there, it works for me.
2013-07-30 02:42:08     thomas_adam     mva: So I'd first rule out your terminal emulator, and go from there.
2013-07-30 02:44:22     mva     uhm, lol. I've little bit disinformed: konsole itself catches bells from tmux (as I checked just now). But Yakuake (which uses konsole's terminal engine) somewhy doesn't... So, thanks and sorry, I'll try to report that to Yakuake :-/
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3) actually, I thought to create bug against Yakuake, but after discussion with Sho (Eike Hein) in IRC I changed my minde that it is possibly KPart bug.

4) bell works fine inside GNU/screen