Re: [Sursound] Reflections from the wodden floor on an ambisonic room..
Fons Adriaensen a écrit : >On Thu, Mar 24, 2011 at 09:29:02PM +0100, Jörn Nettingsmeier wrote: >> On 03/24/2011 09:21 PM, Fons Adriaensen wrote: >> >>> With just 2 more speakers (4 + 6 + 4 + 1) you would not only have >>> better first order but also the option to reproduce in full 2nd >>> order - assuming the right decoder. >> >> out of curiosity: in what way is such a layout superiour to a >> dodecahedron (with speakers on the faces, not the vertices)? > >It's marginally better for horizontal directions, and worse for >'down' sources, since the bottom speaker is missing. But down to >-45 degrees elevation it's as good as the dodecahedron. > >OTOH, I've been experimenting with a 1+6+8+6+1 system for full >3rd order, and this very clearly outperforms an icosahedron >(with just 2 more speakers). To my suprise, it's almost perfectly >'isotropric' even in the vertical plane - there's no sign of any >preferred directions. > >Ciao, > >-- >FA > >___ >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] Reflections from the wodden floor on an ambisonic room..
Hello David, This sounds great! Congrats in getting the resources together to make this happen. I see there have been a number of comments regarding possible set ups--I'll add a few thoughts here as I've been thinking about putting together a 2nd order system. I was thinking of something along the lines of either an icosahedron, or a modified icosahedron. http://en.wikipedia.org/wiki/Icosahedron http://en.wikipedia.org/wiki/File:Icosahedron_model.JPG Placing speakers at the vertices means you'd need 12. The 2nd link above illustrates an arrangement for a true icosahedron. You'd have 3 speakers on the floor, 3 on the ceiling, and the remaining 6 on stands. (These 6 would be by the yellow struts in the photo link above.) The modification I was thinking of would be to bring the 6 speakers on stands into a hexagon on a plane. Why? It makes it easy to set up--but more importantly, I'd now have two speakers set up at +/-60deg for stereo compatible playback. OR, it is also possible to do a bit more rearranging (rotating and adding 2 more speakers) to include a 5.0 array in the set-up. -- Re the floor I'd think about throwing some carpets or rugs down. Reducing reflections can make a big difference. My best, Jo Joseph Anderson 27 Hungate, Pickering, North Yorkshire, YO18 7DL, UK On 24 Mar 2011, at 3:15 pm, david monacchi wrote: > we're planning to build in Pesaro-Italy a small ambisonic studio with 13 > loudspeakers (full 3D - 4@-45°, 4@0°, 4@+45°, 1@90°).. We're now in the > process of moving walls, treating acoustically the room, etc.. The room will > be 5.00 x 4.60 x 3.20h and we are planning to treat it to be as more 'dead' > as possible.. > > In order to have a 'pleasant' space, we're thinking to put a wodden floor > which, to a certain degree, will also help absorbing some low frequencies.. > > My question is: > considering that the room will be semi-anechoic, is the reflection from the > wodden floor really compromizing for the correct soundfied reconstruction? > Are there studies that you know with experimental data, or simply your direct > experience on this? ___ Sursound mailing list Sursound@music.vt.edu https://mail.music.vt.edu/mailman/listinfo/sursound
Re: [Sursound] Reflections from the wooden floor on an ambisonic room..
> The modification I was thinking of would be to bring the 6 speakers on stands > into a hexagon on a plane. > Why? It makes it easy > to set up--but more importantly, I'd now have two > speakers set up at +/-60deg > for stereo compatible playback. OR, > it is also possible to do a bit more rearranging (rotating and adding 2 more > speakers) to include a 5.0 array in the set-up. I have the setup that you might be thinking of, that is a hexagon with one speaker at front center, The +- 60 degrees speakers works fine for stereo if one moves the listening position back from the "ambisonic hotspot" For stereo and surround listening. The +- 120 degree speakers maps fine into 5.1 back channels as 5.1 back speakers really are back/side speakers. The radius of the setup is probably limited by the flore to roof distance. If you place 4 speakers at +- 60 and +- 120 degrees vertically referenced to the center front speaker you will get a 10 channel ambisonic system with height, Fons has already created a decoder setup for ambdec of this layout for me. According to Fons it is not a bad setup refering to the symmetry, and for the power amp you can use 2 home teater amplifiers with external decoder inputs. You have to get the volume control/gain setting identical for this to work well. I speculate more symmetric solution would be to use 4 speakers on the floor and 4 in the roof, Placement defined by "rotating" the side speakers in the hexagon +-60 degrees with the front and back speakers as rotational axis. This will also enable construction of a symetric layout with a slighty wider radius if the radius is limited by room height. But this will require 14 channels. - Bosse -Original Message- From: sursound-boun...@music.vt.edu [mailto:sursound-boun...@music.vt.edu] On Behalf Of Joseph Anderson Sent: den 25 mars 2011 12:10 To: Surround Sound discussion group Subject: Re: [Sursound] Reflections from the wodden floor on an ambisonic room.. Hello David, This sounds great! Congrats in getting the resources together to make this happen. I see there have been a number of comments regarding possible set ups--I'll add a few thoughts here as I've been thinking about putting together a 2nd order system. I was thinking of something along the lines of either an icosahedron, or a modified icosahedron. http://en.wikipedia.org/wiki/Icosahedron http://en.wikipedia.org/wiki/File:Icosahedron_model.JPG Placing speakers at the vertices means you'd need 12. The 2nd link above illustrates an arrangement for a true icosahedron. You'd have 3 speakers on the floor, 3 on the ceiling, and the remaining 6 on stands. (These 6 would be by the yellow struts in the photo link above.) The modification I was thinking of would be to bring the 6 speakers on stands into a hexagon on a plane. Why? It makes it easy to set up--but more importantly, I'd now have two speakers set up at +/-60deg for stereo compatible playback. OR, it is also possible to do a bit more rearranging (rotating and adding 2 more speakers) to include a 5.0 array in the set-up. -- Re the floor I'd think about throwing some carpets or rugs down. Reducing reflections can make a big difference. My best, Jo Joseph Anderson 27 Hungate, Pickering, North Yorkshire, YO18 7DL, UK On 24 Mar 2011, at 3:15 pm, david monacchi wrote: > we're planning to build in Pesaro-Italy a small ambisonic studio with 13 > loudspeakers (full 3D - 4@-45°, 4@0°, 4@+45°, 1@90°).. We're now in the > process of moving walls, treating acoustically the room, etc.. The room will > be 5.00 x 4.60 x 3.20h and we are planning to treat it to be as more 'dead' > as possible.. > > In order to have a 'pleasant' space, we're thinking to put a wodden floor > which, to a certain degree, will also help absorbing some low frequencies.. > > My question is: > considering that the room will be semi-anechoic, is the reflection from the > wodden floor really compromizing for the correct soundfied reconstruction? > Are there studies that you know with experimental data, or simply your direct > experience on this? ___ 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] Ambisonics setup
So just to review things... I would like to take a multichannel performance and encode it in an ambisonic format, then decode it and send it to multiple speakers. I want to also be able to easily configure the number of speakers. My performance environment is Max/Ableton. So on the encode side I could use Ambisonic Max externals or Malham's VST mixer modules. Can someone give me an idea what I should do on the decode side? Is there some hardware decoder I need to get? Should I use another computer and use a software decoder? Thanks, Anthony On Wed, Mar 16, 2011 at 8:09 AM, Anthony Palomba wrote: > I am very interested in this as well. I would like to eventually add > multichannel > capabilities to my performances. > > I would also add the question... > > If I want the setup to be scalable, that is to be able to go from a 4 > channel cube > to a 12 channel configuration, what do I need to keep in mind? > > > > > Anthony > > > > On Wed, Mar 16, 2011 at 6:23 AM, Darren - Bradley < > i...@sacredresonance.com.au> wrote: > >> Hi I am looking at recording 4 mono tracks with different samples on them >> and then (not recording in ambisonic format) just in 'Ableton Live' - doing >> an ambisonic setup with four speakers in a cube (room) > to create a better >> setup then quadaphonic >> >> what do people suggest to do this I would like to route 4 mono tracks out >> of Albeton Live into say max/msp or audiomulch then output into ambisonics >> setup? >> >> How do I do this ? >> >> Thanks >> Darren >> Adelaide >> >> ___ >> Sursound mailing list >> Sursound@music.vt.edu >> https://mail.music.vt.edu/mailman/listinfo/sursound >> > > -- next part -- An HTML attachment was scrubbed... URL: <https://mail.music.vt.edu/mailman/private/sursound/attachments/20110325/de8e87a1/attachment.html> ___ Sursound mailing list Sursound@music.vt.edu https://mail.music.vt.edu/mailman/listinfo/sursound
Re: [Sursound] Ambisonics setup
On 03/25/2011 05:29 PM, Anthony Palomba wrote: So just to review things... I would like to take a multichannel performance and encode it in an ambisonic format, then decode it and send it to multiple speakers. you might be interested in a paper i did for last year's ambisonic symposium, which deals with just this situation: http://stackingdwarves.net/public_stuff/linux_audio/ambisonic_symposium_2010/nettingsmeier_ambisonic_systems_for%20electro-acoustic_concerts-rev3.pdf there's also a video of the presentation: http://stackingdwarves.net/public_stuff/linux_audio/lac2010/day2_1130_General_purpose_Ambisonic_playback_systems_for_electroacoustic_concerts.ogv I want to also be able to easily configure the number of speakers. My performance environment is Max/Ableton. So on the encode side I could use Ambisonic Max externals or Malham's VST mixer modules. Can someone give me an idea what I should do on the decode side? Is there some hardware decoder I need to get? Should I use another computer and use a software decoder? consider jack and ambdec (been mentioned before). -- 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
[Sursound] Reflections from the wooden floor on an ambisonic room
When I was the R&D teaboy at Wharfedale in the late 70's, I tried stereo in our anechoic chamber; expecting great things w/o pesky room reflections. The results were terrible; poor stereo sound as well as formal localisation which was the reason for the experiment. Both much poorer than in a normal listening room. Peter Fryer told me that BBC Research had tried the same thing with the same results. They found putting a plywood floor down improved the sound and localisation.[1] MAG knew of this experiment and always advocated speakers close to room boundaries rather than well away as the pseudo prophets would have it. His reasoning was that if early reflections came from the same general direction, they would not confuse. I should also point out that simulating localisation w/o "some" reflections is likely to be inaccurate.[3] There are several reports of poor Ambi demos in Anechoics; including the false prophet Floyd who repeats this ad nauseum. However, he may not have been using a proper Ambisonic Decoder.[2] I'm not convinced of the need for "semi(?) anechoic" listening rooms, ambisonic or otherwise ... except for Joern's "... very convincing renderings of semi-anechoic or free-field conditions. " However, I'd urge that any purpose built listening room or studio have wonky walls, floor & ceiling. Perfectly parallel surfaces have terrible flutter echoes and you end up applying so much treatment to deal with these that your room becomes too dead. Prof Peter Lord, Salford recommended at least 2 degrees wonkiness. Julian Wright, Celestion finally managed to simulate and confirm this in the late 90's when Patrick Macy, PAFEC developed the 1st successful acoustic boundary element (we were Beta testers). Wonky walls give you much more flexibility to choose your room reverb profile > [Richard, I know what you are thinkingyet again, I couldn't help but > mention the Hankel functions...sorry :-) ] Duu...uh! Professor, does " ... substituting the spherical Bessel/Hankel (j_n / h_n) functions with traditional Bessel/Hankel functions (J_n / H_n) ... " for NFC with "line arrays" give a simple Minimum Phase 3dB/8ve filter? My calculator has no big B or H button. [1] I've been trying to find the BBC Research report w/o success. If anyone knows it, please post. It might be mentioned in "Stereophonic image sharpness" - Harwood, WW vol74 1968 p207-11 The Kingswood Warren anechoic was rather bigger than ours. [2] "Is my decoder Ambisonic?" - Heller et al, preprint 7753, AES San Francisco 08. This is BLaH3 and includes "Designing Classic Ambi Decoders for Dummies". [3] "Loudspeaker and the Stereo Image" - Millward, HFN 29, nov84 ___ Sursound mailing list Sursound@music.vt.edu https://mail.music.vt.edu/mailman/listinfo/sursound
