bkil vs. programming

Using Lubuntu 12.04 for connections to icewm on Ubuntu 12.04. The exact configuration involves hosting a pulse sound server on each thin client , and configuring applications on the remote desktop to pipe back sound to the respective thin client. A trusted environment is assumed here, so please refer to the PulseAudio Network documentation on freedesktop.org and various general security guidelines (firewalls, tunnels, IPsec, VPN, etc.) if you're planning anything serious. Thin client setup: Purge any left over configuration: rm -Ri ~/.pulse Install PulseAudio: sudo apt-get install pulseaudio dbus-x11 Enable local sound access (not sure if needed): sudo adduser $USER pulse; sudo adduser $USER pulse-access then log out and log in again Give local and network access to the sound: cp -t ~/.pulse/ /etc/pulse/default.pa # APPIP="type application server IP address here" echo "load-module module-native-protocol-tcp auth-ip-acl=127.0.0.1/32;$APPIP/32" >...

I wonder how far one could transmit using only sound waves in open air? I am considering something that would not be intrusive, so it needs to emit below the regulated acceptable ambient sound pressure limits (about 30-40dB here). I only intend to operate it intermittently, maybe for a few seconds in every hour - depending on attainable bandwidth. My ultimate goal is to be able to transfer about an SMS in a run, but I would be more than happy to make trade-offs that could result in quieter operation. Higher frequency carriers could both provide more bandwidth easily and be inaudible at the same time, but there's a catch. They say, sound waves below about 1kHz usually penetrate air much better than ultrasounds. I need to test this specifically, but about at most 500Hz-1000Hz looks like a hard upper limit for long range transmission according to the graphs. Another drawback of larger wavelengths is the enormous sized dish that would be needed to concentrate the beam of sound. By the ...

I am interested in simulating the generation of the sound of bells. My ultimate objective is to synthesise a bicycle bell. I had done some web research on the topic, but it is not easy to find concrete implementation details. I had to resort to a bell manufacturer's site that included a lot of details on the sound generation modes of church bells in general. Thankfully, it also had a few graphs on the sound spectrum of these, so I had a good starting point. I then started coding some test routines (sadly in C++), and got pretty promising results after some fiddling with constants and the like. I am pleased with the end result, as it closely resembles the real thing. What is still left, is to record and analyze spectrograms of those bells that are used with bicycles. I have previously tried tweaking the constants of the church bell with no luck.