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
Re: [Sursound] Minim AD7 for sale
On 05/03/2011 08:03 AM, Ronald C.F. Antony wrote: Similarly, what does a SoundField mic output? A/B format. Now translate that into 5.1. That's what's a realistic production flow. and it does not work very well. nobody who is producing 5.1 the usual way (i.e. without using a soundfield) will buy what you get out of this process, and ambisonic lovers who have heard really good renderings of a soundfield microphone won't be too impressed, either. on the other hand, if you have a third or even fourth order signal available, you can apply bruce wiggins' steering magic and get a really nice 5.1 rendering out of it. can the FOA fans please stop crying wolf whenever there is talk about HOA? if you want to listen on FOA systems, that's totally fine with me, and the music that i record will work ok on such systems. but if you want to bring ambisonics into the industry, it's either HOA or go into a quiet corner to die. the argument that any talk of HOA will be detrimental to ambisonics uptake is sentimental BS. HOA is no black magic, and six speakers aren't that expensive, either. go try the stuff, then come back to whine about it. People are not going to have Eigenmics or stuff like that, and only some things will be synthesized sounds that can be generated in HOA. 99.99% of all stereo recordings out on the market are pan-potted mono with some ambience thrown in, either synthesized or captured with stereo room mics. this very same production technique can be used with HOA, drop-in, no questions asked. with some extra work and a few hoops to jump through, you can do classical recordings that will combine the advantages of the soundfield mike with HOA stability. it's no messier than 5.1 or other surround techniques that are in the market today. please, guys, HOA is not exclusively owned by the contemporary electro-acoustic bogeyman that is trying to eat your mahler. nor does working in HOA imply you have to throw your beloved integrexes and meridians out. there's a very nice way down from HOA recordings to FOA rigs, but no real way from FOA productions to HOA rigs (with the very notable exception of the harpex renderer, which i love, but it's no excuse for us to keep sitting on our tetrahedral first-order asses for the next 30 years). So again, realistic sources and production is going to be B-Format base, mostly even tossing the Z-axis. And that's good enough for now. which is demonstrated most eloquently by the glaring success of first-order ambisonics, which has been dominating the audio market for years, as we all know. ronald, go out there, talk to people in the industry, demonstrate your FOA systems, get some real-world feedback. been there, done that. try it, it's very enlightening. 1st OA is something that can be grasped by the average engineer, recording band member, etc. 1 channel for the mono sound, plus three differential channels for the X, Y and Z axes. That's about as intuitive as it gets without being totally wrong. Now try to explain HOA to your average musician. Haha! You really think HOA is going to take off if the average garage band member can't wrap their head around it? it's not really any more difficult. any recording hobbyist who can grasp M/S stereo can grasp arbitrary order ambisonics, at least on the same level that your average sound engineer has an understanding of how stereo works. this is no longer an argument, this is xenophobia. i have written HOA tutorials so simplistic that i fear some mathematicians are crying for blood. So if the Ambi-Snobs could come back from their space mission and set foot on the ground for a while, then 1stOA actually would have a chance. yeah, right. we screwed up :) Once 1st OA is as widely used as stereo is today, THEN it's time to push further. One doesn't feed a baby with a steak! hmmm. the problem is that your baby has wrinkles and whitish whiskers (plus, it seems, a stiff upper lip), so maybe it's time to acquaint it with ale and beef. there's a time in life when breast-feeding, for all its evident joys and advantages, does become kind of awkward. at the age of 35, i'm happy to have moved on :) -- Jörn Nettingsmeier Lortzingstr. 11, 45128 Essen, Tel. +49 177 7937487 Meister für Veranstaltungstechnik (Bühne/Studio) Tonmeister VDT http://stackingdwarves.net ___ Sursound mailing list Sursound@music.vt.edu https://mail.music.vt.edu/mailman/listinfo/sursound
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. The policy is available here: http://www.derby.ac.uk/LIS/Email-Policy ___ Sursound mailing list Sursound@music.vt.edu https://mail.music.vt.edu/mailman/listinfo/sursound
[Sursound] HOA standards (was: Re: Minim AD7 for sale)
On 03/05/2011 09:18, Jörn Nettingsmeier wrote: .. but if you want to bring ambisonics into the industry, it's either HOA or go into a quiet corner to die. the argument that any talk of HOA will be detrimental to ambisonics uptake is sentimental BS. HOA is no black magic, and six speakers aren't that expensive, either. go try the stuff, then come back to whine about it. Sounds like you are positioning six speakers to be the new industry standard. Industries like quality, of course. But they also like a defined standard they can all manufacture to, and promote easily and effectively as a ~physical~ product clearly differentiated from the competition, by being either way cheaper, or way better, or way simpler, or with luck, all three. So that is definitely a step in the right direction. Please don't take this the wrong way, but: exactly what/which industry are you referring to here? The audiophile market dominated by high-end high-price hand-made products; the home cinema market not so much dominated as owned by 5.1 (which is ~five~ speakers plus a sub); the games market; the public entertainment/installation/large-venue market; broadcast? Oh, and content providers including composers? The Creative labs system that came with my old PC has one sub in an 8.5inch cube, and five tiny satellites (no stands) with a 2inch drive unit. Total cost by itself perhaps £50. All things considered, it is very surprising how good it sounds. For general film listening, it does the job. Six full-range speakers (presumably) will cost rather more, along with whatever amp/receiver is needed. 5.1 works pretty well domestically; the front three straddle the TV (assuming they are not already built in), and the other two can be parked, er, wherever the furniture permits, hopefully safe from predation by the smaller resident fast-moving carbon-based lifeforms. We know they are used for sfx and bits of ambience (and the odd spaceship flyover), so their positioning is not critical at all. A few users may actually get out the tape measure and protractor, and say how much better Star Wars sounds that way. Of course for music you fire up the trusty stereo. You wrote: on the other hand, if you have a third or even fourth order signal available,... So which should it be - third or fourth order? The Industry needs to know. Yes it is cool to have the intellectual choice (the more buttons to press the better), gives the informed user a tremendous sense of skill and power, but for an industry standard it would almost certainly be necessary to settle on one or the other, or you get a format war. The opinion on the street is that both DVD-A and even SACD are dead. So I don't see the the industry relishing going there again. The hot tickets are iPods and 3D TV. Software is too easily copied, so there needs to be a defined and protectable (ideally, uncopyable) hardware product in there somewhere. . which is demonstrated most eloquently by the glaring success of first-order ambisonics, which has been dominating the audio market for years, as we all know. A bit disingenuous - that failure (at least partly by the UK government at the time) was predominantly one of marketing (or the lack of it). Had certain cards been played well, 'Dolby 5.1' could actually have been Ambisonics 5.1. The patent on 5.1 decoding I suspect didn't in fact help. The industry was stung by the abject failure of Quad, and only the power of Dolby combined with the shock and awe factor of the new sfx-based film industry was able to get 5.1 established. At least to begin with, nobody associated it with music listening. And of course for a while the only place you could actually hear it was in a cinema. ronald, go out there, talk to people in the industry, demonstrate your FOA systems, get some real-world feedback. been there, done that. try it, it's very enlightening. So again, which industry are we talking about, and what new format should we promote to them? Something that can be mandated as a standard by the AES, RIAA, ISO or whatever (these connectors, that digital stream format, this presumably new read-only piracy-proof delivery medium; or perhaps encrypted live streaming from the cloud, sold as a premium service). From your comments, it would seem to be a six-speaker layout, with either a third or fourth-order stream. Pre-decoded to six channels so it can fit on a DVD (with instructions to the user to reconfigure their 5.1 setup), or supplied as HOA requiring a decoder? The industry would very likely want to remove the either and or parts. Looks like this new standard will again exclude height. Oh well - those spaceship flyovers will still be shoulder-high. Or sound like earthquakes. Perhaps the high-end industry can add value by offering up to ten audio outputs, if you have the extra speakers. Or maybe 24. That might work. Or 12, or 25... And probably it actually needs to be 6.1, so
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.
Re: [Sursound] Minim AD7 for sale - Speaker configs.
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
Re: [Sursound] Minim AD7 for sale - Speaker configs.
from psychoacoustics we cannot really hear directions of sound below 80 Hz I know that it is frequently written, but it's not true. Of the two localization mechanisms active at low frequencies, Interaural Time Differences (ITDs) are the ones that give useable localization cues in free space. The time difference depends only on the direction of the source and not on the frequency. Unofrtunately there is very little information in the psychoacoustical literature about low-frequency localization. They consider 250 Hz to be 'low' and 100 Hz to be very low. Maybe some day I'll do some research on that... It is true that the threshold of hearing rises substantially at low frequencies, and for that reason localization acuity decreases. Here's what I think really happens. For low frequency sounds reproduced in ordinary rooms, the first arrival at the listener's two ears naturally has ITDs that correspond to the direction of the source. After a short period of time, reinforcement of the sound by reflections from the room boundaries changes the phase of the sounds at the ears. This can be more easily seen by considering the modal structure of the room at low frequencies. The room has relatively few modes and the sound wave quickly becomes constrained to travel in the modes. Because of the relative energy of the transverse, oblique, and tangential modes, the sound effectively comes from the direction of the mode, not of the source. In practice, large ITDs AND ILDs are seen at the listener's ears. As a result, the percept will probably be that the sound is coming from a direction other than its actual source. This is what I actually hear when using low frequency test signals in real rooms. But there's more going on that that. Almost always, the low-frequency sound has actually a fairly broadband spectrum. With that sort of signal the auditory system clearly evaluates several cues as to the source direction and gives a best estimate of the actual direction of the source. There are good reasons to use several subwoofers in a multichannel reproduction system. At least the following two papers support that idea. [1] Subkey, A., Cabrera, D., Ferguson, S.; Localization and Image Size Effects for Low Frequency Sound, AES preprint 6325 (2005 May) [2] Martens, W., The impact of decorrelated low-frequency reproduction on auditory spatial imagery: are two subwoofers better than one? presented at the AES16th International Conference, Rovaniemi, Finland, (1999 April) Having said that, I only have one (large!) subwoofer in my multichannel listening room. But the reason for it has more to do with $$$ than my believing that one is enough. Eric - Original Message From: Bo-Erik Sandholm bo-erik.sandh...@ericsson.com To: Surround Sound discussion group sursound@music.vt.edu Sent: Wed, May 4, 2011 4:41:02 AM 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
