3-D Surround Sound With Two Speakers
As you probably don’t know, I am currently in the Electrical Engineering program, with a specialization in DSP. I’ve just finished a project for my Audio Signal Processing course, which let me (and you too, if you care to read my report, featuring source code) create surround sound using only two speakers.
Typical two-speaker stereo sound can only render sound sources from between the two speakers. However, using this method, sounds can be made to come from 90 degrees left or right, above, or even behind the listener. Pretty neat, eh?
How it Works
At MIT in 1995, some crazy guys decided to record the impulse response of sounds from a bunch of different angles using microphones crammed in the ear canals of a fake human head. Using the impulse responses they measured, we can simulate the frequency characteristics of sound reflecting off your outer ears and shoulders and passing through your head. Then we can apply those characteristics to any source wav file we want.
Then, we use some crazy math (detailed in the report) to use the impulse responses measured at the positions of the speakers relative to your head to cancel out the directional effect of sound coming from the speakers.
Give it a Listen
If you have headphones handy, you can listen to a short sample. If you’re crazy enough to be more deeply interested than what this post supplies have any questions about it, I practically insist that you leave a comment, or send an email to design(a)adambard period com.
January 21st, 2011 at 1:36 am
Your project looks very interesting. This could be an alternative instead of buying new products. Is this difficult to do by people who do not understand about Electrical Engineering?
January 21st, 2011 at 2:02 pm
This project was done with software, so I would extend the list of people that can do it easily to include developers and such. But, it would be difficult to someone who couldn’t follow the text of my report, since as far as I know no commercial product exists for this purpose.
If you want to try it yourself, the source code is linked in the aforementioned report.