>From >http://en.wikipedia.org/wiki/Sound_localization#Evaluation_for_low_frequencies
Evaluation for low frequencies For frequencies below 800 Hz, the dimensions of the head (ear distance 21.5 cm, corresponding to an interaural time delay of 625 µs), are smaller than the half wavelength of the sound waves. So the auditory system can determine phase delays between both ears without confusion. Interaural level differences are very low in this frequency range, especially below about 200 Hz, so a precise evaluation of the input direction is nearly impossible on the basis of level differences alone. As the frequency drops below 80 Hz it becomes difficult or impossible to use either time difference or level difference to determine a sound's lateral source, because the phase difference between the ears becomes too small for a directional evaluation. -----Original Message----- From: sursound-boun...@music.vt.edu [mailto:sursound-boun...@music.vt.edu] On Behalf Of Bo-Erik Sandholm Sent: den 4 maj 2011 13:41 To: Surround Sound discussion group Subject: Re: [Sursound] Minim AD7 for sale - Speaker configs. Yes, I have a few woofers available BUT according to what I understand from psychoacoustics we cannot really hear directions of sound below 80 Hz, as the ear/brain is changing method of decoding soundwaves between 80 to 100 Hz? So do I really need more than a pair driven in mono (or 4) to even out the excitation of the room modes? If I where to add a low frequency decoder how should I do that? Is it not so that the speaker feed to all of the 10 speakers are in phase for frequencies lower than Some "undefined" frequency? That is using Ambdec? Should I have a highpass filter before or after the decoder for the 10 "small" speakers, if I add a low frequency feed, either mono or decoded? Bo-Erik -----Original Message----- From: sursound-boun...@music.vt.edu [mailto:sursound-boun...@music.vt.edu] On Behalf Of Peter Lennox Sent: den 4 maj 2011 11:32 To: Surround Sound discussion group Subject: Re: [Sursound] Minim AD7 for sale - Speaker configs. Quick suggestion: - as you're having to use more than 8 channels anyway, you're likely to be using a 16 channel card; thus, you would have some channels left to decode (horizontal only) to 3 or 4 subs Dr Peter Lennox School of Technology University of Derby, UK tel: 01332 593155 e: p.len...@derby.ac.uk -----Original Message----- From: sursound-boun...@music.vt.edu [mailto:sursound-boun...@music.vt.edu] On Behalf Of Bo-Erik Sandholm Sent: 04 May 2011 08:09 To: Surround Sound discussion group Subject: Re: [Sursound] Minim AD7 for sale - Speaker configs. I still want to suggest a setup that I will soon have in operation, I have written about it before. It uses 10 channels, it is a hexagon in the horizontal plane with a speakers at front back. The Z is handled by for speakers, placed where the 4 hexagon side speakers will end up if the Hexagon is rotated 90 degrees around a axis through the front and back hexagon speakers. Fons A has created a ambdec for me of this setup. I have the possibility to have all speakers except the 2 floor speakers permanently mounted due to my room geometry. I have the 2 floor speakers mounted on a long wooden plank letting me getting them in place quickly. I have been rethinking my amplifier setup and will now use 3 modules of 4 channel sure swiched amps instead of 2 Home theater amplifiers. The shure amp modules (4 x 100W) cost 98USD including a switched power supply, an will give 30 watts per 8 ohm speakers, I will only be using 2 power supplies so the total material cost is at the moment 3 x 44 US + 2 x 48 USD, that is less than 240 USD. http://www.parts-express.com/pe/showdetl.cfm?Partnumber=320-302 I will be using second hand Kef KHT-2005.2 "Eggs" as speakers. It is a bit of a "bother" that 10 instead of 8 channels are used, when it comes to the sound card setups... Regards Bo-Erik -----Original Message----- From: sursound-boun...@music.vt.edu [mailto:sursound-boun...@music.vt.edu] On Behalf Of Aaron Heller Sent: den 3 maj 2011 20:04 To: Surround Sound discussion group Subject: Re: [Sursound] Minim AD7 for sale On Tue, May 3, 2011 at 10:14 AM, Fons Adriaensen <f...@linuxaudio.org> wrote: > On Tue, May 03, 2011 at 07:15:29PM +0530, umashankar mantravadi wrote: >> >> in fact angelo recommended that i arrange the eight speakers as two >> crossed squares. two speakers in front and back, and four speakers >> mid bottom left and right and mid top left and right, the only >> problem is i do not see a readymade decoder > > A variation on this is an horizontal rectangle, 1 unit wide and 1.73 > deep, and a vertical rectangle in the YZ plane 1 unit high and 1.73 wide. > Or the same rotated 90 degrees. Looking from above you see an hexagon. > > This somewhat improves the rE for horizontal directions (not much), at > the expense of all others. Anything outside the +/- 30 degrees > elevation region will become very fuzzy. I had one of these set up at home for a couple of days and found it better than a horizontal hexagon. The impression of height is a welcome addition to the sense of envelopment. I had a fader set up in Bidule so you could change the Z gain to compare horizontal-only with periphonic. The entire listening panel (my son and I) preferred having the height info, but the rest of the family didn't appreciate having a couple of ladders in the living room. I also tried it with the vertical rectangle in the XZ plane. That works too. Contact me off list if you want the Ambdec config files I used. Aaron Heller <hel...@ai.sri.com> Menlo Park, CA US _______________________________________________ Sursound mailing list Sursound@music.vt.edu https://mail.music.vt.edu/mailman/listinfo/sursound _______________________________________________ Sursound mailing list Sursound@music.vt.edu https://mail.music.vt.edu/mailman/listinfo/sursound _____________________________________________________________________ The University of Derby has a published policy regarding email and reserves the right to monitor email traffic. If you believe this email was sent to you in error, please notify the sender and delete this email. Please direct any concerns to info...@derby.ac.uk. 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