Tue Oct 07, 2008 10:34 pm
Hi all,
I decided to post this topic after coming away from a discussion of RAM requirements in the General Discussion area.
For those of you unfamiliar with Ambiophonics as a concept, go here:
www.ambiophonics.org
In brief, it is a serious and credible way (or group of ways, more properly) to provide playback conditions — especially for, but not limited to, 'staged' music performances — of sufficient realism to convince the ear-brain mechanism that the listener is indeed in the intended soundfield. Results will be further enhanced through specific decisions made in the recording process (for new projects, obviously).
Virtual pipe organ performance has no essential difference in its objectives, and as such is 'fair game' for the concept. Here is a short list of observations and tactics for your consideration:
1. Spatial impression is vital for realism.
2. 'Brute force' multi-channel session recordings are not only resource-hungry, but cannot accurately depict the location soundfield, primarily due to the unavoidable contamination of 'stage area' sounds leaking into the surround microphones — a serious compromising of the characteristics of the location soundfield.
3. Use of the 'Ambiophone' — a concept based on stereo mic principles with head-type shadowing and conscious suppression of non-frontal sounds — allows for the following:
a) correct angular imaging with inter-aural crosstalk cancellation (IACC) such as RACE (with primary 2-channel playback loudspeakers angled — unusually — at 10-25 degrees rather than stereo's typical 60 degrees, an arrangement known as the 'Ambiopole')
b) reconstruction of the venue acoustic (or substitute acoustic) via multi-channel IR convolution, inherently free from direct-type sound contamination, and involving no storage-resources penalty, not to mention the attraction of extraordinary soundfield versatility
4. While this approach allows for the fullest expression of the concept (assuming 2 channel recording), 2-channel recordings using a variety of traditional approaches also benefit enormously from this playback method.
5. Playback room treatment to effectively suppress undesirable reflections is strongly recommended.
6. Perusal of the website material and freely downloadable PC and Mac routines for IACC will provide answers to most questions. You will see that, while it is a 'system' which works brilliantly with 2-channel record/playback, it can be expanded to include scientifically valid full surround-type recording (though this is not really applicable to forward-direct sound + enveloping acoustic events like pipe organ), even to the extent of properly including height data.
All in all, a great leap forward and endorsement of the frequent listener experience that headphone playback is 'best' — I think not for the primary reason that it avoids small-room playback environment distortions, nor for (in spite of) the admitted directional distortion of headphone playback, but because of the REMOVAL OF TIMBRAL DISTORTION CAUSED BY THE COMB-FILTERING RESULTING FROM WIDELY-SPACED LEFT/RIGHT SPEAKERS OF TRADITIONAL STEREO AND MULTI-CHANNEL SPEAKER ARRAYS.
Looking forward to others' thoughts. Just thought I'd kick the ball into play.
Cheers,
Stephen. PS I am in the process of constructing a dedicated room along these lines, with broadband absorption, front and rear Ambiopoles, with additional IR surround field loudspeakers, delivery through a 24-channel sound card. I will report on progress with pictures as they become available.
I decided to post this topic after coming away from a discussion of RAM requirements in the General Discussion area.
For those of you unfamiliar with Ambiophonics as a concept, go here:
www.ambiophonics.org
In brief, it is a serious and credible way (or group of ways, more properly) to provide playback conditions — especially for, but not limited to, 'staged' music performances — of sufficient realism to convince the ear-brain mechanism that the listener is indeed in the intended soundfield. Results will be further enhanced through specific decisions made in the recording process (for new projects, obviously).
Virtual pipe organ performance has no essential difference in its objectives, and as such is 'fair game' for the concept. Here is a short list of observations and tactics for your consideration:
1. Spatial impression is vital for realism.
2. 'Brute force' multi-channel session recordings are not only resource-hungry, but cannot accurately depict the location soundfield, primarily due to the unavoidable contamination of 'stage area' sounds leaking into the surround microphones — a serious compromising of the characteristics of the location soundfield.
3. Use of the 'Ambiophone' — a concept based on stereo mic principles with head-type shadowing and conscious suppression of non-frontal sounds — allows for the following:
a) correct angular imaging with inter-aural crosstalk cancellation (IACC) such as RACE (with primary 2-channel playback loudspeakers angled — unusually — at 10-25 degrees rather than stereo's typical 60 degrees, an arrangement known as the 'Ambiopole')
b) reconstruction of the venue acoustic (or substitute acoustic) via multi-channel IR convolution, inherently free from direct-type sound contamination, and involving no storage-resources penalty, not to mention the attraction of extraordinary soundfield versatility
4. While this approach allows for the fullest expression of the concept (assuming 2 channel recording), 2-channel recordings using a variety of traditional approaches also benefit enormously from this playback method.
5. Playback room treatment to effectively suppress undesirable reflections is strongly recommended.
6. Perusal of the website material and freely downloadable PC and Mac routines for IACC will provide answers to most questions. You will see that, while it is a 'system' which works brilliantly with 2-channel record/playback, it can be expanded to include scientifically valid full surround-type recording (though this is not really applicable to forward-direct sound + enveloping acoustic events like pipe organ), even to the extent of properly including height data.
All in all, a great leap forward and endorsement of the frequent listener experience that headphone playback is 'best' — I think not for the primary reason that it avoids small-room playback environment distortions, nor for (in spite of) the admitted directional distortion of headphone playback, but because of the REMOVAL OF TIMBRAL DISTORTION CAUSED BY THE COMB-FILTERING RESULTING FROM WIDELY-SPACED LEFT/RIGHT SPEAKERS OF TRADITIONAL STEREO AND MULTI-CHANNEL SPEAKER ARRAYS.
Looking forward to others' thoughts. Just thought I'd kick the ball into play.
Cheers,
Stephen. PS I am in the process of constructing a dedicated room along these lines, with broadband absorption, front and rear Ambiopoles, with additional IR surround field loudspeakers, delivery through a 24-channel sound card. I will report on progress with pictures as they become available.
