From: Jez San Subject: Convolvotron & Focal Point Performance Comparisons Date: Tue, 3 Dec 91 13:13 GMT I have both the Convolvotron and Focal Point at work, and have been playing around with them. I have been able to do A-B tests and other such comparisons. For the money, Focal Point represents excellent value. It provides one channel of sound adequately, and the effect is good. The Convolvotron costs much more. For that, you get better interpolation as you sweep the sounds around, you get more sound channels (4, instead of 1) and you get higher quality digital filtering. For instance, The Convolvotron software allows up to 512 taps in the Filter, where Focal Point uses considerably less. Even when using 4 channels, the Convolvotron uses 128 taps, which is still higher than Focal Point's. The Convolvotron comes with full sourcecode and a few different head models (HRTF filter data) so you can experiment with other 3d sound effects and the difference between people's heads. Focal Point comes preprogrammed with a reasonably good head model, but I see no way of changing it dynamically without them altering the software. Since Focal Point ships on a Mac, it is inherently friendlier to use than the Convolvotron software. The demo 'control panel' allows you to move the sound source around with the mouse, alas it has no control over distance. Convolvotron's demo software uses the keyboard to move the sound source around, but you can move it more precisely (in terms of angles) and you CAN change the distance, which gives a better 3d effect. It is hard for me to choose one over the other to recommend since they are so obviously aimed at different markets. The Tron is more for research and high end 3d sound, being the 'brute force processing power' way to produce 3d sound. Focal Point is much more affordable, but offers you less in processing power, and consequently less 3d sound channels. To be honest, I think both companies' products aren't perfect, and I did indeed need to play with both at the same time to learn about this subject. I think both companies will be producing newer, perhaps cheaper versions of their boards and software in the coming year. What with new processing power coming down in price, I bet we will see a texas C40 based 3d sound processor from someone, someday. It sure is a powerful DSP. -- Jez San, Argonaut Software Limited, London, England.