Re: [PD] [OT] gallery installation sound
Hallo, Hans-Christoph Steiner hat gesagt: // Hans-Christoph Steiner wrote: Usually acoustic measurements are done with impulses, AFAIK. An ideal impulse actually has all frequencies in it, so it's useful for that kind of thing. Plus it's easy to differentiate between the initial signal and the room effects just based on time. Actually I think, engineers prefer to use frequency sweeps instead of pulses nowadays. The problem with pulses is, that they are hard to get right: You need a clean pulse and a very silent environment: The main problem with using Dirac pulses in an acoustical measurement is that as a result of their very short duration and finite amplitude, they contain very little energy, and measure- ment accuracy will be limited by the signal to noise ratio of the equipment used and of the system itself. While it is possible to use Dirac pulses reproduced by a loudspeaker in the con- trolled environment of an acoustics laboratory, this is all but infeasible in most real life situa- tions, e.g. for measuring a room or concert hall, where there will always be background noises of some sort. This is from Fons Adriaensen's LAC paper: http://lac.zkm.de/2006/papers/lac2006_fons_adriaensen_01.pdf Fons then explains sine sweeps as an alternative method: The advantage of using a sweep is that at any time we produce only a single frequency, and any distortion introduced will consist of the har- monics of that frequency only. If we use a rising frequency sweep, the harmonics will be gener- ated ahead of the same frequencies appearing in the signal. So after deconvolution, any dis- tortion will appear as spurious peaks in negative time in the impulse response, and most of it can then be edited out easily. This method's origin according to Fons is a paper by A. Farina: Angelo Farina. 2000. Simultanuous measurement of impulse response and distortion with a swept-sine technique. Audio Engineering Society Preprint 5093. It is implementes in Fons' ALIKI software, that he presented at LAC2006. Ciao -- Frank Barknecht _ __footils.org_ __goto10.org__ ___ PD-list@iem.at mailing list UNSUBSCRIBE and account-management - http://lists.puredata.info/listinfo/pd-list
Re: [PD] [OT] gallery installation sound
An excerpted acoustic study of an abandoned Soviet aircraft bunker. Max Borisov wears ear-mount binaural microphones, and I test the space with bricks and stones. Max and I found this technique very interesting, as it allows one person to literally become a human microphone, and the That is the good old Kunstkopfaufnahme (dummy head recording) http://en.wikipedia.org/wiki/Dummy_head_recording which is used for live-like live recordings http://de.wikipedia.org/wiki/Binaurale_Tonaufnahme in your case with a real head. I have to check out your recordings and place some stuff into the bunker :) Cheers, Malte -- Malte Steiner media art + development -www.block4.com- ___ PD-list@iem.at mailing list UNSUBSCRIBE and account-management - http://lists.puredata.info/listinfo/pd-list
Re: [PD] [OT] gallery installation sound
That's a sweet concept, and a fun way to collaborate with active field recording. I'll have to try that (giving you guys reference cred of course)! ~Kyle On 2/13/07, Derek Holzer [EMAIL PROTECTED] wrote: I've used very rough impulse recordings to do binaural placement for sounds--as well as pure abstract textures as Malte suggested--with very nice results. See soundfiles and descriptions below from Karosta Project (Latvia, 2002-3) http://karosta.edworks.net/ best, d. *** binaural.tunnel.study.1 [w/max.borisov][OGG 2min00sec 1.67Mb] http://www.gracies.org/derek/audio/field.recordings.2/binaural.tunnel.study.1.ogg An excerpted acoustic study of an abandoned Soviet aircraft bunker. Max Borisov wears ear-mount binaural microphones, and I test the space with bricks and stones. Max and I found this technique very interesting, as it allows one person to literally become a human microphone, and the other to perform for that audience/recorder [many thanks to Aaron Ximm for inspiration in this and other matters]. A clever soul might use these acoustic signatures to place other sounds in the same space virtually... *** Original Formanta EMS-01 Synthesizer improvisation [OGG 2min08sec 1.34Mb] http://www.gracies.org/derek/audio/formanta.original.edit.ogg Formanta.Drone [Surface.Noise] [OGG 7min10sec 4.92Mb] http://www.gracies.org/derek/audio/formanta.drone.edit.ogg The first is an excerpt of a live improvisation made on Maxim Borisov's Formanta EMS-01 synthesizer. This is a big, nasty Russian synth that is almost totally useless for melody, but has this amazing noise-driven Low Frequency Oscillator with an array of filters behind it. All sounds on the first track came only from this random sequencer, without laying a finger on the keys. The second track resulted from a digital cross-breeding with surface noise from an old Soviet marching record--instant texture and depth! -- derek holzer ::: http://www.umatic.nl ---Oblique Strategy # 160: Towards the insignificant ___ PD-list@iem.at mailing list UNSUBSCRIBE and account-management - http://lists.puredata.info/listinfo/pd-list -- http://theradioproject.com http://perhapsidid.blogspot.com (()()()(()))()()())( (())(())()((( ))(__ _())(()))___ (((000)))oOO ___ PD-list@iem.at mailing list UNSUBSCRIBE and account-management - http://lists.puredata.info/listinfo/pd-list
Re: [PD] [OT] gallery installation sound
On 2/13/07, Frank Barknecht [EMAIL PROTECTED] wrote: Actually I think, engineers prefer to use frequency sweeps instead of pulses nowadays How fast of a sweep are you talking about? Seconds or milliseconds? Is this the 50 and 80 ms bit that the paper mentions? If we use a rising frequency sweep, the harmonics will be gener- ated ahead of the same frequencies appearing in the signal. So after deconvolution, any dis- tortion will appear as spurious peaks in negative time in the impulse response, and most of it can then be edited out easily. What a great way to use an artifact of the FFT to one's advantage. Awesome! ~Kyle -- http://theradioproject.com http://perhapsidid.blogspot.com (()()()(()))()()())( (())(())()((( ))(__ _())(()))___ (((000)))oOO ___ PD-list@iem.at mailing list UNSUBSCRIBE and account-management - http://lists.puredata.info/listinfo/pd-list
Re: [PD] [OT] gallery installation sound
Hallo! Usually acoustic measurements are done with impulses, AFAIK. An ideal impulse actually has all frequencies in it, so it's useful for that kind of thing. Plus it's easy to differentiate between the initial signal and the room effects just based on time. Actually I think, engineers prefer to use frequency sweeps instead of pulses nowadays. The problem with pulses is, that they are hard to get right: You need a clean pulse and a very silent environment: Well, there are also problems with swept sines of course ... ;) Other methods are e.g. - with MLS (http://en.wikipedia.org/wiki/Maximum_length_sequence) - I think there is also an mls example in the iem_tab library. -Least Square Error methods (see system identification example in the adaptive library) - with noise (more energy than in a dirac impulse) - auto-, crosscorrelation methods - ... LG Georg ___ PD-list@iem.at mailing list UNSUBSCRIBE and account-management - http://lists.puredata.info/listinfo/pd-list
Re: [PD] [OT] gallery installation sound
Thank you all for your responses - each was very helpful! I am particularly interested (mostly out of curiosity) in how to measure the room with convolution - would I blast some pink noise and then re-record it with a good microphone, and then perform a frequency analysis on that? I am sure I can look this up somewhere. Would this then yield the resonant frequencies in the room? Kevin -- http://pocketkm.blogspot.com -- http://pocketkm.blogspot.com ___ PD-list@iem.at mailing list UNSUBSCRIBE and account-management - http://lists.puredata.info/listinfo/pd-list
Re: [PD] [OT] gallery installation sound
Hallo, Kevin McCoy hat gesagt: // Kevin McCoy wrote: Thank you all for your responses - each was very helpful! I am particularly interested (mostly out of curiosity) in how to measure the room with convolution - would I blast some pink noise and then re-record it with a good microphone, and then perform a frequency analysis on that? I am sure I can look this up somewhere. Would this then yield the resonant frequencies in the room? This nice paper may be interesting: http://www.kokkinizita.net/linuxaudio/papers/aliki.pdf http://www.kokkinizita.net/linuxaudio/index.html Ciao -- Frank Barknecht _ __footils.org_ __goto10.org__ ___ PD-list@iem.at mailing list UNSUBSCRIBE and account-management - http://lists.puredata.info/listinfo/pd-list
Re: [PD] [OT] gallery installation sound
On 2/7/07, Kevin McCoy [EMAIL PROTECTED] wrote: there are many sound scientists and artists on the list so I thought I would ask if anyone knows of resources to look at for dealing with these kinds of issues? How are other artists sorting these things out? Any links or recommendations would be very helpful. Low ends tend to get very muddy and the highs and mids spill all over the place. Are there certain tricks I could use in mixing or placement/kinds of speakers to preserve the highs and mids better in a difficult space? This might be a difficult question since you can't hear the piece in person, but even general advice would be very helpful. I'm no sound scientist, but wouldn't just some ordinary foam of the type people put in their music studios help? It sounds like you are having trouble with unwanted and weird reverberations, which the foam should lesson. Having performed music in such spaces (concrete and metal), I've got a pretty good idea of the kind of acoustic nightmare you are probably facing... ~David ___ PD-list@iem.at mailing list UNSUBSCRIBE and account-management - http://lists.puredata.info/listinfo/pd-list
Re: [PD] [OT] gallery installation sound
I haven't done any sound installations, but in thinking about a particular space had some ideas for dealing with these acoustical issues. You could design the sound for the space, working with rather than against the acoustics. If possible, you could capture the impulse response of the space (perhaps in multiple locations), then as you work on the sound, use convolution to hear how it will sound in the space. I guess the degree to which you can adapt your piece depends on how far along you already are. Alternatively, you could acoustically treat the space using acoustic foam or rigid fiberglass. This page has tons of good info: http://www.ethanwiner.com/acoustics.html Ben Kevin McCoy wrote: Hello all, Apologies for the ot post; I've got my final thesis show coming up in early April and I'm doing all sound work using Pd. The gallery space I am using is actually quite poor for acoustics, as it's got a concrete floor and metal roofing. It's relatively small though - two hallways each about 10 feet by 30 feet large (3 by 9 meters if you like) making a T shape. I would like to do two 4 channel sound installations, perhaps one for each hallway. I know there are many sound scientists and artists on the list so I thought I would ask if anyone knows of resources to look at for dealing with these kinds of issues? How are other artists sorting these things out? Any links or recommendations would be very helpful. Low ends tend to get very muddy and the highs and mids spill all over the place. Are there certain tricks I could use in mixing or placement/kinds of speakers to preserve the highs and mids better in a difficult space? This might be a difficult question since you can't hear the piece in person, but even general advice would be very helpful. Also if any of you have documentation of your own installations, I would love to see them. Thanks! Kevin -- http://pocketkm.blogspot.com http://pocketkm.blogspot.com ___ PD-list@iem.at mailing list UNSUBSCRIBE and account-management - http://lists.puredata.info/listinfo/pd-list ___ PD-list@iem.at mailing list UNSUBSCRIBE and account-management - http://lists.puredata.info/listinfo/pd-list
Re: [PD] [OT] gallery installation sound
If you can (and it's a big if), try to suspend your acoustic dampening panels above the heads of people. This will have a big effect on your reverb problems without disrupting the space in the hallway. I like the suggestions on this thread. very insightful Chuck ___ PD-list@iem.at mailing list UNSUBSCRIBE and account-management - http://lists.puredata.info/listinfo/pd-list
Re: [PD] [OT] gallery installation sound
We went to the Kimmel Center last semester in acoustics class, and this is exactly what they do. They have a huge foil on top that they raise or lower depending on the size of the ensemble. Now, they also have huge empty wells on both sides of the auditorium, and if they need wider reverb they open these huge walls in the auditorium so the sound can go all around- but I'm guessing that's beyond your means. I also like the impulse response idea, if nothing else you can learn from doing it. The only thing I can add is that if you try delaying the sound at one end of the room, you can make people feel like the sound is coming from the other end; then, maybe, they'll move towards that end and get more direct sound. -Chuckk On 2/7/07, Charles Henry [EMAIL PROTECTED] wrote: If you can (and it's a big if), try to suspend your acoustic dampening panels above the heads of people. This will have a big effect on your reverb problems without disrupting the space in the hallway. I like the suggestions on this thread. very insightful Chuck ___ PD-list@iem.at mailing list UNSUBSCRIBE and account-management - http://lists.puredata.info/listinfo/pd-list -- Far and away the best prize that life has to offer is the chance to work hard at work worth doing. -Theodore Roosevelt ___ PD-list@iem.at mailing list UNSUBSCRIBE and account-management - http://lists.puredata.info/listinfo/pd-list
