Le Fri, 03 Jun 2011 10:47:23 +0100, dw <surso...@dwareing.plus.com> a écrit :
> > I did a basic experiment with twos subs and a sound generation > > software (PureData with the equal_power_pan extension). I panned a > > bass sine tone from left to right and back, changing the frequency > > between 40Hz and 160Hz. I was able to localize the sine tone at > > certain frequencies, depending on my position in the room; at 70Hz > > the tone was very easy to localize. So it's definitely possible to > > create a sound field with directional bass, intentionally or not. > > I suspect you are just modulating the standing wave pattern.. Yes, I was probably just doing that. Room modes, standing waves, etc. But... The consumer audio industry stated with authority that bass should just fill the room, and that that's what sounds good. I was not supposed to buy a second sub, I was supposed to stick one in some corner and be happy forever. One paper caught my attention: "Spatial auditory display using multiple sub-woofers in two different reverberant reproduction environments" (easy to google). It studies our ability to localize a pair of left/right subs and front/back subs, in an anechoic room and a small domestic room, for frequencies ranging from 40 to 100Hz. In both rooms, our ability to localize front or back bass tones is very bad (about 40% accuracy). In a anechoic room we can localize the left/right bass tone without error. In a domestic room the results are not as good, but we are still able to localize L/R bass tones down to 80Hz with 80% accuracy. I suppose that the same test in a small room with bass traps would give better results. I once asked Fons A. what kind of speakers I should get for Ambisonics and he replied that full range speakers are mandatory. With my small room and small budget it was a challenge. It took me a while to figure how to build lots of bass reflex enclosures for small full-range drivers, and I was ready to build them. Then I learned that a dedicated decoder can be used with three subs. Someone mentioned the KEF "Eggs" as good domestic speakers, and I was lucky to find three sets of discontinued KEF home theatre speakers at a very good price (with the smallest "Eggs" and the "Kube-1" sub). The Eggs are excellent. The Kube doesn't have much bass extension, but it works. So now I am playing with my new toys, but I'm not ready to install an ambisonics setup (I need to find a sound card with 16 outputs). In the meanwhile I am adapting my XTC setup in order to use two satellites and two subs. I must admit that your filter is my favourite right now, although I should compare it with the others (RACE, BACCH) later this summer. > Here is the 'uncut' version, if you would like to compare. I think it > is less suitable for general use, so don't want it to be the offical > distributed version. You seem to be the only one interested. The file > will be removed in a day. There's a bit more bass coming out of your "uncut" filter, but there's some cancellation when the bass signal is mono (equal in both channels). I still prefer when the stereo signal is sent directly to a pair of subs at +-30 degrees. -- Marc _______________________________________________ Sursound mailing list Sursound@music.vt.edu https://mail.music.vt.edu/mailman/listinfo/sursound
