Re: [Sursound] [ot] analog vs. digital
Sorry about continuing the off-topic... David Pickett kirjoitti: What amazed me about the quality of the sound on these old cassettes and analog tapes is that the quality has been preserved They are often very good, depending on what kind of a recorder the recording was made. You can also reduce tape hiss and other noises afterwards. I always thought that reducing wow and flutter was almost impossible or at east very expensive. I was surprised that it can be done. You can listen to an example of a quite extreme W&F reel to reel tape recording, that I worked with: http://www.tonfiks.fi/9 The page is in Finnish, but the wow & flutter example is the first one. The one without any image, just the text links. Some hum/noise/clicks have also been reduced from the "after" (jalkeen) clip Some of the data on my CDRs and DATs on the other hand, has disappeared completely! I have certain CDR:s from the beginning of the 90's, that have become brown from the edge. That's a warning to make new copies. With the DAT tapes it is possible that the data can be recovered, but you'd need to find a DAT player with a tracking and tape adjustments that fit the tape. The adjustments of the recorder you used may have shifted. A colleague of mine once used five separate DAT tape decks to recover all data of a 55 minute recording, getting pieces from different parts of the tape with different players. Eero ___ Sursound mailing list Sursound@music.vt.edu https://mail.music.vt.edu/mailman/listinfo/sursound
Re: [Sursound] Sony PCM? (was Re: DTS Headphone:X)
Not long ago I made an extensive search for software that would do at least decoding of tape noise reduction systems. Practically nothing found, no convolution based or VST:s. No Dolby, no DBX, not even versions of single-ended analog NR, such as Philips DNL. An earlier version of the Stereo Tool VST had some kind of Dolby B decoding. http://www.stereotool.com/ ...but it isn't there anymore. I have guesses why. :-) Anyway, it didn't do the job exactly as Dolby B should. That's why I have Dolby 361 and DBX180 in my shelf. Eero ___ Sursound mailing list Sursound@music.vt.edu https://mail.music.vt.edu/mailman/listinfo/sursound
[Sursound] Eigenmike
Hi all, Just wondering if anyone could give me any information on how the Eigenmike works, since there is not allot of information available. I am very familiar with the Soundfield mic and how it generates the directional information W,X,Y, and Z through three FO8 patterns and an omni, this being in the form of four audio signals which are combined in different amplitudes and phase depending on speaker location, however regarding the Eigenmike it generates 25 audio signals which corresponds to 4th order? I understand that eigenbeams can be formed and pointed in any direction, however what are the pick up patterns of each capsule? and does the signals that you get from the mic correspond to say the way the Soundfield mic works, (excuse my simplistic idea) for example are the first four channels of the Eigenmike W,X,Y and Z for example? Thank you in advance, Paul Power -- next part -- An HTML attachment was scrubbed... URL: <https://mail.music.vt.edu/mailman/private/sursound/attachments/20130502/8ada69e8/attachment.html> ___ Sursound mailing list Sursound@music.vt.edu https://mail.music.vt.edu/mailman/listinfo/sursound
Re: [Sursound] Sony PCM? (was Re: DTS Headphone:X)
Pretty much the 'Holy Grail' of audio.I can't ever imagine there being a software solution for those noise reduction systems as they were very level sensitive... but i'd be really happy if i could be proven wrong.. Not long ago I made an extensive search for software that would do at least decoding of tape noise reduction systems. Practically nothing found, no convolution based or VST:s. No Dolby, no DBX, not even versions of single-ended analog NR, such as Philips DNL. An earlier version of the Stereo Tool VST had some kind of Dolby B decoding. http://www.stereotool.com/ ...but it isn't there anymore. I have guesses why. :-) Anyway, it didn't do the job exactly as Dolby B should. That's why I have Dolby 361 and DBX180 in my shelf. Eero ___ 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/20130502/e22353e8/attachment.html> ___ Sursound mailing list Sursound@music.vt.edu https://mail.music.vt.edu/mailman/listinfo/sursound
Re: [Sursound] what mics do you use? - Eric's second order mic
Eric's second-order soundfield microphone looks very good for recording and down mixing to other microphone patterns. I mostly use the tetramic that I have to produce crossed 8 recordings. Looks like Erik have found a very good way to capture signals for using as source for virtual mic recordings. There is now of course a need for a software in the likeness of the of VVmic :-) If we can find or select for microphone elements that are reasonably well matched, do anyone have an idea of how necessary individual calibration would be, as we now have for the tetramic? I am really thinking of the possibility of DIY construction of the second order microphone as it looks like the design have very good inherent designed capabilities, or am I wrong? Can a skeleton be created for printing by a 3D printer if we can choose an electret element that is good enough ? I do wonder if it is possible to have a low signal matrix between the microphones and the recorder to create a more ideal first order mic, or just decrease the needed recorded channels to 6, this to match a 6 channel Tascam DR-680 :-). From me you see a very clear sign of the "want it now at a low cost" syndrome as we see in a lot of places nowadays :-) I really enjoyed reading the paper. Best Regards Bo-Erik Sandholm -Original Message- From: sursound-boun...@music.vt.edu [mailto:sursound-boun...@music.vt.edu] On Behalf Of Eric Benjamin Sent: den 29 april 2013 22:08 To: Surround Sound discussion group Subject: Re: [Sursound] what mics do you use? I'd like to expand just a bit on what Dave said. The narrowing of the pattern of microphones at high frequencies is equivalent to the addition of higher order spherical harmonics into the directionality. I recently went through the exercise of decomposing the pattern of a 1" capsule into its spherical harmonics and it took up to 10th order to do a good approximation at 16 kHz. If one were to derive either an omni (monopole) or a Figure 8 (dipole) by adding or subtracting capsules then half the higher order harmonics would remain, resulting in a polar pattern that differs greatly from what was desired. This is true even assuming that you could make the capsules coincident, which you can't. A mental model of a soundfield microphone at HF is of four beams pointing out into space from the locations of each of the capsules. The non-coincidence is of course a separate effect. If we were to use perfect, point-sized capsules then they could conceivably have perfect cardioid patterns. But the spacing effects are still there. I've measured most of the available soundfield microphones to determine the value of r. It's a little difficult because the center of the array isn't available, but one can measure from the center of one diaphragm to another and get r from that. If the capsules are cylinders of length l and diameter d, then r = l +.2887d SF MkIV and MkV1.47 cm (from literature) SF SPS2002.71 cm (from measurement AGM MR1 and MR22.27 cm (from measurement) Tetramic1.77 cm (from measurement) Note that r for the SPS200 is almost twice the value for the MkIV type design. Long capsules make things worse! I've built prototypes here with r = .7 cm, but none of those are ready for use. Finally, Aaron Heller and I presented two papers at the 133rd AES convention that deal with some of these matters, in particular the diffuse-field response. They are: Calibration of Soundfield Microphones using the Diffuse-Field Response http://www.aes.org/tmpFiles/elib/20130429/16453.pdf A second-order soundfield microphone with improved polar pattern shape http://www.aes.org/tmpFiles/elib/20130429/16470.pdf I hope that the illustrations in these papers will make clearer what we've been talking about. Either Aaron or I will be happy to send a copy to anyone who is interested. Eric Benjamin - Original Message ___ Sursound mailing list Sursound@music.vt.edu https://mail.music.vt.edu/mailman/listinfo/sursound
Re: [Sursound] Eigenmike
The Eigenmic uses omni directional microphones on a solid sphere, so the directional sensitivity is due to diffraction on the surface sphere (like the Neumann M50), hence the patterns change with frequency. These can be processed into spherical harmonics or directly into directional patterns. There are a number of tradeoffs that must be made at low-frequencies (due to noise) and high frequencies (due to spatial aliasing). Typical practice is the record the capsule outputs and then produce directional outputs directly on playback. I think you can download the processing software and manual from mh. Here are some papers. IMHO, [2] is the most readable as an introduction. [1] J. Meyer and G. W. Elko, “SPHERICAL MICROPHONE ARRAYS FOR 3D SOUND RECORDING,” *AUDIO SIGNAL PROCESSING FOR NEXT-GENERATION MULTIMEDIA COMMUNICATION SYSTEMS, Ch. 3*, pp. 1–23, 2004. [2] Z. Li, R. Duraiswami, and N. A. Gumerov, “Capture and Recreation of Higher Order 3D Sound Fields via Reciprocity,” *Proceedings of ICAD-04*, vol. July, p. 8, May 2004. [3] T. D. Abhayapala and D. B. Ward, “Theory and design of high order sound field microphones using spherical microphone array,” presented at the Acoustics, Speech, and Signal Processing (ICASSP), 2002 IEEE International Conference on, 2002, vol. 2. [4] A. O'Donovan, R. Duraiswami, and D. Zotkin, “Imaging concert hall acoustics using visual and audio cameras,” *Proc IEEE Int Conf Acoust Speech Signal Process*, pp. 5284–5287, Jan. 2008. Aaron Heller (hel...@ai.sri.com) Menlo Park, CA US On Thu, May 2, 2013 at 2:20 AM, Paul Power wrote: > Hi all, > Just wondering if anyone could give me any information on how the > Eigenmike works, since there is not allot of information available. I am > very familiar with the Soundfield mic and how it generates the directional > information W,X,Y, and Z through three FO8 patterns and an omni, this being > in the form of four audio signals which are combined in different > amplitudes and phase depending on speaker location, however regarding the > Eigenmike it generates 25 audio signals which corresponds to 4th order? I > understand that eigenbeams can be formed and pointed in any direction, > however what are the pick up patterns of each capsule? and does the signals > that you get from the mic correspond to say the way the Soundfield mic > works, (excuse my simplistic idea) for example are the first four channels > of the Eigenmike W,X,Y and Z for example? > > > Thank you in advance, Paul Power > -- next part -- > An HTML attachment was scrubbed... > URL: < > https://mail.music.vt.edu/mailman/private/sursound/attachments/20130502/8ada69e8/attachment.html > > > ___ > 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/20130502/973da2a3/attachment.html> ___ Sursound mailing list Sursound@music.vt.edu https://mail.music.vt.edu/mailman/listinfo/sursound
Re: [Sursound] [ot] analog vs. digital
This is of course true, what David says. Audio people are as they are-- they tend to think a lot more about audio than they listen to actual music-- but musicians(eg David) know that the highest frequencies have essentially sod all (since this is UK based list intellectually, I use the Brit vulgarism here) to do with music as music. For literal realism--of course one needs them because they are there in reality. But for music as it means something as music not really so much. Moreover the top octave frequencies are ALWAYS WRONG. There is no stereo mechanism (and not really a surround one either) to get the highs to be as they are in reality when they are recorded and played back. They always detach themselves somewhat from their sources and become a sort of blurring out of texture rather than the texture being firmly attached to its precise source--this is especially true for recordings of large ensembles where the higher frequencies sound like a layer of high frequency noise laid on like jam on a piece of toast. Digital is good because first of all it is really reliable on pitch and second one can do things with it--DSP can do stuff that one could not do with analogue processing. But otherwise, analogue works fine. The real problem with cassettes was how they were duplicated. Plus the fact that the players (and recorders) were highly unpredictable as to exact speed. (I have a deck with adjustable speed for that reason-- otherwise things tend to be shifted in pitch in oddball ways. It is typical of the audio industry that until digital audio came along, which is pitch perfect by nature, the industry treated pitch with complete contempt--off centered records, cassette decks with any old speed, not to mention speed stability problems. etc. Sometimes one can feel that the audio industry ends up with music strictly by accident!) Robert On Wed, 1 May 2013, David Pickett wrote: At 16:47 01-05-13, Sampo Syreeni wrote: On 2013-05-01, David Pickett wrote: So, analog still rules! Please die horribly. ;) You say that, but I have recently been transferring old cassettes to hard drive and, given that they have a limited bandwidth of about 15kHz, the noise is not intrusive and I have been amazed at the quality -- a quality that mp3 files do not approach. If, as some people do, you actually want to enjoy the music, you can do so with the cassettes that I transferred. David ___ 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] Eigenmike
Hi Paul, the Eigenmike captures 32 channels of input from 32 omni-directional capsules as positioned centrally on facets if the 8.4cm diameter sphere were a truncated icosahedron. 32 channels, 4th order capture (n + 1)^2. The mic captures a spherical harmonic deconstruction of a soundfield on the spherical baffle. The beamformer processing is done under VST or through Eigenstudio software. The Eigenbeam can be steered with 180 degrees of elevation and 360 degrees of azimuth with several selectable patterns; cardioid, super and hyper up to 3rd order, omni, dipole and torus. The captured spherical harmonic information from all 32 channels is rendered directionally in the Eigenbeamformer as selected for to up to 16 outputs, 3rd order. Due to spatial aliasing caused by capsule size and distribution the processing is split into two modes above and below 9kHz. In the paper, "Handling Spatial Aliasing in Spherical Array Applications" by Meyer and Elko, the designers discuss approach es to address this, although nothing specifically states how it was achieved in the EM. The first four channels on the EM are dependent on element positioning on the baffle (not available in latest release notes online) so they don't correspond directly to the design of the Soundfield mic. Through mh's beamforming the W,X,Y,Z could be generated through dipole steering and omni although I've never attempted to render that output. Cheers, Anthony Tucker SID: 309278198 PH: 0411 303 339 From: sursound-boun...@music.vt.edu [sursound-boun...@music.vt.edu] on behalf of Paul Power [pro_powe...@yahoo.co.uk] Sent: 02 May 2013 19:20 To: sursound@music.vt.edu Subject: [Sursound] Eigenmike Hi all, Just wondering if anyone could give me any information on how the Eigenmike works, since there is not allot of information available. I am very familiar with the Soundfield mic and how it generates the directional information W,X,Y, and Z through three FO8 patterns and an omni, this being in the form of four audio signals which are combined in different amplitudes and phase depending on speaker location, however regarding the Eigenmike it generates 25 audio signals which corresponds to 4th order? I understand that eigenbeams can be formed and pointed in any direction, however what are the pick up patterns of each capsule? and does the signals that you get from the mic correspond to say the way the Soundfield mic works, (excuse my simplistic idea) for example are the first four channels of the Eigenmike W,X,Y and Z for example? Thank you in advance, Paul Power -- next part -- An HTML attachment was scrubbed... URL: <https://mail.music.vt.edu/mailman/private/sursound/attachments/20130502/8ada69e8/attachment.html> ___ 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] Eigenmike
"Through mh's beamforming the W,X,Y,Z could be generated through dipole steering and omni although I've never attempted to render that output." Edit - I've never attempted to render from that input (The dangers of hitting send before reading my post...) Anthony Tucker SID: 309278198 PH: 0411 303 339 From: sursound-boun...@music.vt.edu [sursound-boun...@music.vt.edu] on behalf of Anthony Tucker [atuc8...@uni.sydney.edu.au] Sent: 03 May 2013 12:29 To: Paul Power; Surround Sound discussion group Subject: Re: [Sursound] Eigenmike Hi Paul, the Eigenmike captures 32 channels of input from 32 omni-directional capsules as positioned centrally on facets if the 8.4cm diameter sphere were a truncated icosahedron. 32 channels, 4th order capture (n + 1)^2. The mic captures a spherical harmonic deconstruction of a soundfield on the spherical baffle. The beamformer processing is done under VST or through Eigenstudio software. The Eigenbeam can be steered with 180 degrees of elevation and 360 degrees of azimuth with several selectable patterns; cardioid, super and hyper up to 3rd order, omni, dipole and torus. The captured spherical harmonic information from all 32 channels is rendered directionally in the Eigenbeamformer as selected for to up to 16 outputs, 3rd order. Due to spatial aliasing caused by capsule size and distribution the processing is split into two modes above and below 9kHz. In the paper, "Handling Spatial Aliasing in Spherical Array Applications" by Meyer and Elko, the designers discuss approach es to address this, although nothing specifically states how it was achieved in the EM. The first four channels on the EM are dependent on element positioning on the baffle (not available in latest release notes online) so they don't correspond directly to the design of the Soundfield mic. Through mh's beamforming the W,X,Y,Z could be generated through dipole steering and omni although I've never attempted to render that output. Cheers, Anthony Tucker SID: 309278198 PH: 0411 303 339 From: sursound-boun...@music.vt.edu [sursound-boun...@music.vt.edu] on behalf of Paul Power [pro_powe...@yahoo.co.uk] Sent: 02 May 2013 19:20 To: sursound@music.vt.edu Subject: [Sursound] Eigenmike Hi all, Just wondering if anyone could give me any information on how the Eigenmike works, since there is not allot of information available. I am very familiar with the Soundfield mic and how it generates the directional information W,X,Y, and Z through three FO8 patterns and an omni, this being in the form of four audio signals which are combined in different amplitudes and phase depending on speaker location, however regarding the Eigenmike it generates 25 audio signals which corresponds to 4th order? I understand that eigenbeams can be formed and pointed in any direction, however what are the pick up patterns of each capsule? and does the signals that you get from the mic correspond to say the way the Soundfield mic works, (excuse my simplistic idea) for example are the first four channels of the Eigenmike W,X,Y and Z for example? Thank you in advance, Paul Power -- next part -- An HTML attachment was scrubbed... URL: <https://mail.music.vt.edu/mailman/private/sursound/attachments/20130502/8ada69e8/attachment.html> ___ 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 ___ Sursound mailing list Sursound@music.vt.edu https://mail.music.vt.edu/mailman/listinfo/sursound
