Archive for the ‘Audio Tech’ Tag

Open Sound Control

Now for some more geeky stuff..

One of the components of my FYP was a communication mechanism between controllers, mapping engins and synthesizers for sound synthesis. Now, the main part of my FYP, the mapping engin, was designed to be cross-platform, and portable. Thus, we needed a communication mechanism able to support this.

MIDI has been one of the most popular communication mechanism for synthesis for many years. But it has had its days. We need a more extendible mechanism, which is not as hardward layer dependent like MIDI. Enter Open Sound Control (OSC).

OpenSound Control (OSC) is an open, transport-independent, message-based protocol developed for communication among computers, sound synthesizers, and other multimedia devices.

I won’t go into the details. You can get them here and here if you are interested.

Anyway, so as a part of my FYP I extended the Java implementation of the OSC protocol, JavaOSC. Here is a paper I co-wrote on it. We called it JOE (Java OSC Extension). Now, don’t laugh. It was supposed to go with MOE (Microcontroller OSC Ethernet), but that’s another story..

Anyway, so I am still working on JavaOSC, though not alone. I have teamed up with the original creator of JavaOSC and other amazing people in the community, to continue this project. You can find out more about it at the sourceforge site. It’s free, in both ways, so feel free to use it, or even better to ‘abuse‘ it.. ;)

Audio Spotlight

There was a lecture/seminar by Prof. Barry Vercoe in NUS today. It was organized by ACM SIGCHI Singapore and SCS SIG on Entertainment Computing and ECE. Basically, it was under the initiative to promote digital media in Singapore.

The nice thing was the who’s who interested in Media from NUS, NTU and Singapore was around. The best thing was that Prof. Vercoe was talking about his own research and the Media Lab at MIT.

The one that caught my attention was AudioSpotlight. I had known about it, but forgotten. There was some controversy about it, but the technology itself is cool..

The idea is to be able to direct the propagation of sound, instead of letting it spread in all directions, as speakers do. This allows you to have personal speakers, that can direct sound specifically towards a small area, using ultrasound. Ultrasound being very directional, can be ‘beamed’.

The idea behind is very simple, but difficult to explain. Audible sound modulated with an ultrasound carrier tends to demodulate itself in a certain pattern, as it propagates through the air. As to why this happens, I think it has something to do with the non-linearity in the relationship between pressure and particle velocity. So one can use this to ‘encode’ the audible sound so that the demodulation can yield itself back.

The uses of this are infinite. There are some listed on the website. Personally, I wait for the time when they can have one on every seat in the bus so that I can turn TVMobile off!! At least for myself…:p

The X-Fi… uncovered..

I am really excited about the X-Fi… I know compared to some really high end stuff out there, this is really nothing. But, its something really good that I can afford.. Well maybe not now…. Hopefully I can buy one from TheWeed if he wins one…:D

Anyway, so.. when am I ever satisfied by just looking at or merely using some really cool peice of technology?? I wanna know how it works?? Especially if you claim things as Creative has claimed… So I was looking for some nice indepth technical reviews done by people on the X-Fi. But sadly, I found only generic stuff, nothing in much detail.

Untill I found these…
Creative X-Fi pt 1
Creative X-Fi pt 2
Creative X-Fi pt 3
Creative X-Fi pt 4

Nice and long review of the X-Fi… :D Now.. if only I had the time to read….

Viva L’Creative…

So I went the latest Creative Warehouse Sale last Friday. And I was so excited!! All the cool technology for me to touch and feel and listen to! Lemme do a summary of the stuff I saw there…

The X-Fi. Creative’s new flagship Sound Blaster. Really cool sound card for the semi-audiophiles out there. Has a really nice upconverting feature. Upconverts from 16bit to 24bit as well as from 2.0 to 5.1! I really wanna know how they do it. I do know though that they need a really poweful DSP (which they sport, something with 10,000 MIPS!!) for all the stuff they are doing..

The HQ-2300D. Really cool headphones. They have their own DAC and Amps..in a small little box.. That means nicer coupling and better sound! No more “damn it i bought these cool guy headphones but there is impedence mismatch with my driver…:'(” Also they support Dolby Digital or DTS inputs, by having its own decoder (inside that box)! This guy can optimise your 5.1 DTS or Dolby Digital for a headphone. Kinda like the Holophonic sound thingy. The best part is that if you dont’t have 5.1 source, it can upconvert the 2.0 to 5.1 for you, just like the X-Fi!!

The Zen Vision M. Saw the so called iPod killer. Have the agree that the UI is not as intutive as the iPod. Took me and TheWeed like 5mins to figure out how to use the scroll pad thingy. Oh and its huge! But still if I ever buy one, might go with Creative. It’s the accessories and extra functions. Oh and also the codec support.

-The Decoders and Mixers. More like connectivity options for the various Creative devices that people own. Nice ideas, especially the fact that they have so many options.

-The Creative In-ear headphones. Keng bought one of those, says they are really as efficient as they promise to be! Have been thinking about those since I heard Robert Heron from Dl.Tv ranting about it!

-The Creative Prodikeys and family. Cool stuff, one day when I know more about music I’ll think about these..

-The S$39 1st Gen mp3 players. Would be fun just to open it up and see whats what!

-The Creative Webcams. Going at insane prices!

So what did I buy?? Nothing..:( What do I want?? The X-Fi, the HQ-2300D and most importantly a Job!!! Would be so cool to work with Creative!! :D

Updates for Minty…

Alright…

Seems that our Minty Mp3 player project will happen afterall. Currently, we have all the ‘raw materials’ including the PCBs and all the ICs and components. We just need some good soldering tools (which I hope to buy) and some good debugging tools like multimeter and oscilloscope (which I hope I wont have to buy…).

Oh and the most important, the PIC programmer. We actually built a Pic-Key. But I am not so sure if it works. Plus, we dont have any extra PICs to burn…:p Whats worst Microchip has stopped sampling many PICs… So there is no way to get the PICs other than buying… :”(

Anyway, just the other day I found this. PIC-PG1. Its by sparkfun, and its only US$ 11 + shipping. Seems a better alternative to our Pic-Key..

And I also found Eagle3D. Eagle is a really great circuit CAD tool that I have been using since I took EE3208. Really good for all student projects. It can produce gerber files so that you can fab the PCB at any fab. I am pretty sure it will work in the NUS PCB fab as well. It takes a little time to learn, but once you get it, its really cool. Its free and you can create your own device if the libraries don’t have the one you want. And do check their libraries, cos they have many many user submissions….

Eagle3D is like a macro for Eagle that allows you convert your Eagle Board layout into a 3D rendering capable file format, through a Eagle ULP. Really cool stuff. The generated file can be viewed through POV-Ray. I did a quick rendeing for Minty, and here are the results.

This is the board layout of Minty…


And this is the 3D version. Cool huh??

Now only if I had more time…..

Binaural recordings…

I knew about binaural recordings for a long time. Never knew the tech behind them. I was looking at Holophonic sound when I remembered about binaural recordings. It seems that its quite simple.

The idea is that, when you do a stereophonic encoding, you tend to miss out certain information with respect to the position of your ears and the sources. It somewhat regenerated when you listen in a when you recreate a stereophonic field, but not totally.

With binaural recording, that information is captured. The most important part of that is the HRTF, head realated transfer function. It basically models the dimensions and relative position of your ears and head. With that information, you can easily regenerate the stereophonic sound image to a greater accuracy. The best part is the way it is captured. Using microphones attached inside the ear of a ‘dummy head’. You can even do it with two microphone attached to your head!!

However, this does mean that such recordings sound better only when heard using headphones, since they are captured at your ear.

Listen to some binaural recording here and here. Remember to put on your headphones…I personally like the InvitationLoud.mp3. It gives you a taste of the capacity of binaural recordings..

So looking around, I saw people selling CDs of music recorded in binaural. And they seem very expensive.

I also found DIY guides to make binaural headphones. Hehe, thats something to try out when I have some time. ;)….

From MP3 to SLS…

Now for some techie stuff...:P:P

Recently, I have been to exposed to a lot of good techie stuff. There were some really cool seminars/tutorials in I2R. And me being the me….I had to go for all, even when they were during exam period. I feel that such things should matter more than exams. But anyway…

So the highlight were these talks by Dr. Jürgen Herre from Fraunhofer Institute for Integrated Circuits (IIS). He has been contributing to MPEG audio standards since the time of MPEG-1. So he’s like pretty big in the field.

The talks were so cool. He talked abt the evolution of the MPEG standards. Its really amazing to see that. I mean how much progress people have made!!! Whats even more amazing is the amount of efforts that have been put in in these things!

For the un-initiated, MPEG-1 or specifically MPEG-1 Layer 3 is what u know as mp3.

In the talk Dr. Jürgen was talking abt the latest MPEG standards. The MPEG-4. For general audio, one can acheive ‘good quality’….rather acceptably good quality at as low as 24kbps!!! And he demo-ed it. And it sounded nice. A bit synth, but that’s if you are very very picky about things. But come on….for 24kbps….i’d take that anyday…..

Today Dr. Jürgen had a ‘tutorial’ about Multi-Channel encoding. The stuff they do so that you can have ur precious 5.1 audio over channels ment for stereo or mono…..Another amazing field. Man I wish I could understand 1/2 the stuff that they were talking about. I mean I kinda got it but not fully. There is so much that people have done. MPEG-Surround the new standards that is gives ‘good quality’ 5.1 in as low as 42kbps!!! Just amazing…

Parametric Coding is the way to go!!!!.…(Ner mind if you dont get it. Else ask me….if you dare…)

I am so gratefull to I2R allowing me to do my FYP there. I get a chance to meet and rub shoulder(in a figurative way) with all these great ppl….I hope I2R has more such cool talks

Anyway, so much for MPEG and mp3s. I still prefer my ATRAC…so back to my Mini-Disk….:P:P

Headphones for Dogs….and Whales????

Alright…

So I am looking for a nice pair of headphones. Not too expensive, but something that gives a nice flat frequency response and undistorted sound at considerably high levels.

With some help I managed to shortlist the Sennheiser HD497.

I was looking for it at a Best Denki store when I chanced upon another headphone from another brand (I seem to forgotten the brand and the model). The technical specs read,”

“Frequency response 20-30000 Hz”

What??? 30000Hz???

Werent we taught in like secondary that a human ear can only hear between 20-20kHz??My course in Acoustic (at DTU) also taught me that human hearing was even worst than what was taught in secondary school. To actually hear a sound at 20kHz, you need to a sound that is as loud as a jet engin!!!!

So what do we do with a headphone that can give out a 30000kHz frequency??

What’s funier is that most of Sony’s headphones sport a frequency response of more than 22kHz! And the more $$ you pay for the pair the more in-audible frequencies your headphones can output!!!

This is exemplified in the Sony MDR-SA5000. Costs US$ 699.99!!! Boasts a frequency response of 5-110,000Hz!!!! And there is no typo here, its “a hundred and ten kilo Hertz“!!!!!!!

The only reason I can think of is that with such headphones, you can not only listen yourself, but let your dog listen as well!!!!

So next time your dog (or your whale) seems bored, go get it a pair of Sony/Sennheiser headphones. And both of you can enjoy the music!