When read carefully the Floyd Toole quote I used includes the words "in normal listening rooms".
Since we are on the subject of reflections, space and images.
My Kodo story:
A few years back I attended a Taiko drum group concert at Maui High School Auditorium. A big, rectangular theater with hard walls. Not pretty acoustics, but a lot of fun with big drums. Plenty loud and no PA needed.
The guest artist was a flute player from Kodo. After a few drum numbers he made his entrance from the lobby, behind us, coming down the aisle playing the flute. I thought this would be an excellent opportunity to hear how well I could place him by sound alone. How good was the "live imaging"? Eyes closed I heard him come down the aisle and pass me on left , proceed down, turn left at the bottom, then go back right up the stairs at the edge of the stage, finally to stop about half way left of center (stage right).
All fine (and easy to predict), until I suddenly heard the flute jump a few feet to the right, then back, then to the right, then back again. That was so startling that my eyes popped open. And what did I see? He was not alone. Quite silently a Japanese dancer, complete with kimono and parasol had arrived on stage. She was a few feet to his left (my right) with the parasol held down in front of her, like a shield. And she was slowly turning, turning, turning.
What I heard was not the flute jump to the right and back again, but the reflection of the flute's sound off the parasol as it passed by him while the dancer turned. I was surprised, to say the least. The angle could not have been more than few degrees, as we were seated more than half way back in the auditorium. I would never had thought it possible to hear that reflection. But I did. I think anyone paying attention would have, to.
The Maui newspaper printed a photo of that very moment to illustrate their story of the concert. Alas, I no longer have the photo.
In my experience this is likely due to the large number of sources in a orchestra, not the hall itself. Having grown up in theaters I can't remember ever having trouble locating an actor on stage by sound alone. Ditto a few musical instruments. Things get much more confused with large numbers of sources playing at once.
My Kodo story:
A few years back I attended a Taiko drum group concert at Maui High School Auditorium. A big, rectangular theater with hard walls. Not pretty acoustics, but a lot of fun with big drums. Plenty loud and no PA needed.
The guest artist was a flute player from Kodo. After a few drum numbers he made his entrance from the lobby, behind us, coming down the aisle playing the flute. I thought this would be an excellent opportunity to hear how well I could place him by sound alone. How good was the "live imaging"? Eyes closed I heard him come down the aisle and pass me on left , proceed down, turn left at the bottom, then go back right up the stairs at the edge of the stage, finally to stop about half way left of center (stage right).
All fine (and easy to predict), until I suddenly heard the flute jump a few feet to the right, then back, then to the right, then back again. That was so startling that my eyes popped open. And what did I see? He was not alone. Quite silently a Japanese dancer, complete with kimono and parasol had arrived on stage. She was a few feet to his left (my right) with the parasol held down in front of her, like a shield. And she was slowly turning, turning, turning.
What I heard was not the flute jump to the right and back again, but the reflection of the flute's sound off the parasol as it passed by him while the dancer turned. I was surprised, to say the least. The angle could not have been more than few degrees, as we were seated more than half way back in the auditorium. I would never had thought it possible to hear that reflection. But I did. I think anyone paying attention would have, to.
The Maui newspaper printed a photo of that very moment to illustrate their story of the concert. Alas, I no longer have the photo.
"Clearly". A researcher comes to a firm conclusion which is different to a view he once held. He has better data now, and has reviewed the work of other researchers in the interim. He goes into print with it. Readers somehow conclude he doesn't have a firm view, particularly if they disagree with him on it.
It's a hard life.
Along those lines I've been experimenting with absorptive materials taped to the tweeter faces of my two-ways, and the before/after difference in spaciousness is quite noticeable, with the bare tweeters exhibiting the more spacious sound.
The question to me is "do we want an enhanced sense of space(we generally do like the you are there thing), a larger source width(we generally do like the 'they are as big as ___'), a more vague image (with all the holes in the recorded soundstage more filled in), and spectral modifications made by reflected off axis response, or do we want to hear the recording as it was mastered? Or somewhere between the extremes?
It's a personal choice. Oh, I guess the other options would include a radical modification of a typical loudspeaker power response tweaked in an attempt to remove the recording process and transport you back to the live recorded event in a wet listening room environment. All a personal choice and they'll all work for some people.
Lesson of the thread,
Dan
It's a personal choice. Oh, I guess the other options would include a radical modification of a typical loudspeaker power response tweaked in an attempt to remove the recording process and transport you back to the live recorded event in a wet listening room environment. All a personal choice and they'll all work for some people.
Lesson of the thread,
Dan
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What if I were to suggest that we sense image location in a stereo reproduction primarily in the following way:
Above 1-2kHZ by amplitude comparisons, below 1-2kHZ by timing comparisons...
Any comments or questions?
Above 1-2kHZ by amplitude comparisons, below 1-2kHZ by timing comparisons...
Any comments or questions?
Backwards inhibition is also called backwards masking. There are many DBT results to be found for this, and almost any audition text will refer to these results.
These processes are usually studied with headphones and binaural hearing will significantly change the results fro reflections not from the same direction as the direct sound.
Of greater interest in this discussion is forward making: to what degree does the direct sound mask the later sound? ie how far down does the reflection need to be to have minimal frequency balance impact? Olive studied this in great detail.
"The detection of Reflections in Typical Rooms", Olive, presented at the 85th AES convention, preprint # 2719 (F-1)
- reflections greater than10ms best heard using impulses
- reflectionsless than 10ms easier to hear using pink noise.
- reflections in the same direction as the first incidence can be 5 to 10 dB above the first incidence before detection;
- lateral reflections increase spaciousness when just above the noticeability threshold;
- vertical reflections in the median plane affect timbre more than spaciousness;
- lateral reflectionsless than 10 ms lead to image spreading;
- lateral reflections from 10 to 40 ms lead to image spreading and spaciousness;
- echo is detectable above 40 ms.
- room RT60 has almost no effect on these effects for reflections delayed no more than 30 ms.
- reflections have to be 7 dB above the absolute detection threshold before they cause an image shift
These processes are usually studied with headphones and binaural hearing will significantly change the results fro reflections not from the same direction as the direct sound.
Of greater interest in this discussion is forward making: to what degree does the direct sound mask the later sound? ie how far down does the reflection need to be to have minimal frequency balance impact? Olive studied this in great detail.
"The detection of Reflections in Typical Rooms", Olive, presented at the 85th AES convention, preprint # 2719 (F-1)
- reflections greater than10ms best heard using impulses
- reflectionsless than 10ms easier to hear using pink noise.
- reflections in the same direction as the first incidence can be 5 to 10 dB above the first incidence before detection;
- lateral reflections increase spaciousness when just above the noticeability threshold;
- vertical reflections in the median plane affect timbre more than spaciousness;
- lateral reflectionsless than 10 ms lead to image spreading;
- lateral reflections from 10 to 40 ms lead to image spreading and spaciousness;
- echo is detectable above 40 ms.
- room RT60 has almost no effect on these effects for reflections delayed no more than 30 ms.
- reflections have to be 7 dB above the absolute detection threshold before they cause an image shift
Some interesting insight
Some readers might be very interested to hear this demo as it does a reasonable job of explaining various elements of room response, power response and localization.
You should listen with high quality headphones.
Saffire PRO 24 DSP Audio Interfaces Saffire PRO 24 DSP
Some readers might be very interested to hear this demo as it does a reasonable job of explaining various elements of room response, power response and localization.
You should listen with high quality headphones.
Saffire PRO 24 DSP Audio Interfaces Saffire PRO 24 DSP
A couple of interesting bits from the Soren Bech studies (Audibility of Individual Reflections in a Complete Sound Field).
Just noticable differences were found for the strength of various room reflections "..for three attributes a) the perceived position of the simulated loudspeaker, b)loudness and c)timbre. As the level of the reflection was decreased, differences for attributes a) and b) also decreased and eventually disappeared. The timbral differences remained after the two other had disappeared. When the timbral differences disappeared, there were no perceptual differences between the two sound fields." In other words different effects occur with reflections at different levels. Timbre or frequency balance modification is happening at a lower level while image spreading and apparent volume increase happen at higher levels.
From part II: "..an increase in the level of individual reflections for a noise signal is most likely to be audible for the first order floor reflection and for reflections from the wall to the left of the listener. (a speaker in the left front corner of the room was simulated) ...the first order reflection from the wall behind the listener also belongs to this group, For a speech signal only the first order floor reflection is most likely to produce an audible effect."
David S.
Just noticable differences were found for the strength of various room reflections "..for three attributes a) the perceived position of the simulated loudspeaker, b)loudness and c)timbre. As the level of the reflection was decreased, differences for attributes a) and b) also decreased and eventually disappeared. The timbral differences remained after the two other had disappeared. When the timbral differences disappeared, there were no perceptual differences between the two sound fields." In other words different effects occur with reflections at different levels. Timbre or frequency balance modification is happening at a lower level while image spreading and apparent volume increase happen at higher levels.
From part II: "..an increase in the level of individual reflections for a noise signal is most likely to be audible for the first order floor reflection and for reflections from the wall to the left of the listener. (a speaker in the left front corner of the room was simulated) ...the first order reflection from the wall behind the listener also belongs to this group, For a speech signal only the first order floor reflection is most likely to produce an audible effect."
David S.
Thanks for that, it's a great demo. And looks like a lot of soundcard for the price. The effects of reflection on coloration are easy to hear and quite striking. I wish that they could expand on that some. But that's not the main point of the demo.
CARA room design software can do this sort of thing, too. I need to learn how to use it.
Thanks Dave and Dave for sharing the info! Those are great tidbits.
Sane and Pano, FWIW my Focusrite interface may be my best audio purchase to date. The Preamps have almost no noise and I just wish I had bought one sooner. Not enough gain for a ribbon on my model, but I'll never use one anyway.
Dan
Sane and Pano, FWIW my Focusrite interface may be my best audio purchase to date. The Preamps have almost no noise and I just wish I had bought one sooner. Not enough gain for a ribbon on my model, but I'll never use one anyway.
Dan
Thanks for a very interesting demo.
But after listening to the demo, I wondered what the devil this gizmo does. Then I read the promo text which was a clear as the demo. It is a recording studio in a box - you can mix and twiddle knobs using headphones. And the twiddling has little to do with the use of headphones which are taken to be kind of OK to start with (or hard to tell from the extraneous verbiage about MIT at the start).
Let's be clear about the take-away message. Speakers and rooms are dramatically different, when viewed through a good lens (as they demostrate). And with their trick card, you can bridge the BIG differences and hear your tracks as they would be with these different worlds of sound reproduction.
In other words, we are back at the pessimistic and relativistic pole of this discussion where you take your chances on mics measurements and specs when you buy or make speakers (such as for the not-really-anonymous speakers they provide curves for) and then you do a personal tweak in your own music room to make it sound right.
On the bright side, they (claim) to have a handle on reconstructing speaker and room sound in order to make it work in headphones. And that means, in theory, you can reverse engineer, so to speak, what they've done to create flat sound.
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Auralization has been around a while now. I can recommend "3-D Sound for Virtual Reality and Multi-Media" by Begault as a good reference. I own a copy, its a good reference.
Dave Dal Farra
Not quite a recording studio in a box 😉. More like a tool that some believe could enable "mixing" using headphones. So, to be clear, it seems as though the manufacturer is attempting to make it easier for novice "recording engineers" to use headphones for "mix and master" operations so they don't need to invest in a proper control/mastering rooms, speakers and other related professional equipment. 😱
right.... I'm sure with these new tools the results will be a great improvement. 🙄
It's hard to believe that one could create a great mix with those $100-$200 studio monitors.... even harder to believe that you could get better results by simulating cheap monitors and a crappy room.😛
Or maybe it's easier to just build our own open baffle/no baffle speaker that reduces the negative influences of our "average" rooms to a large extent. 🙂
I've been thinking about getting one of the VMR audio card to improve listening experience of my headphones (the inside my head sound is not very peasant)... But I'm finding it really hard to justify the $400-500 for a toy to make my headphones sound more like crappy speakers when I could be investing my hard earned money on some nice ESL panels for my next DIY build.
I found wiring-up a Bauer circuit (mimics cross-ear head influences) to be a nice headphone toy/mod.
About those odd yet valuable Nagra-Beyer DT-48 headphones, seems to me that itinerant recording engineers can "hear through" or "hear despite" the idiosyncrasies of individual studios. If so, this gizmo makes things worse because the engineer is already mentally "correcting" for his/her setting and then this gizmo puts a bunch of twists into the road. Likewise, maybe little need for standardization of studios.
I wonder if conductors can likewise "hear despite" different halls (some do re-arrange the orchestra to suit themselves or a given piece of music too).
If all true, then we are back to the question of what kind of absolute standards do we carry in our heads - obviously we do have some standards in all the senses despite being skewed by the immediate context ("ground"). Otherwise, we could never say, "that sounds bright".
About those odd yet valuable Nagra-Beyer DT-48 headphones, seems to me that itinerant recording engineers can "hear through" or "hear despite" the idiosyncrasies of individual studios. If so, this gizmo makes things worse because the engineer is already mentally "correcting" for his/her setting and then this gizmo puts a bunch of twists into the road. Likewise, maybe little need for standardization of studios.
I wonder if conductors can likewise "hear despite" different halls (some do re-arrange the orchestra to suit themselves or a given piece of music too).
If all true, then we are back to the question of what kind of absolute standards do we carry in our heads - obviously we do have some standards in all the senses despite being skewed by the immediate context ("ground"). Otherwise, we could never say, "that sounds bright".
hello,
I don't like to make negative critics, but bentoronto can be skeptical about this demo : it's 7 mins of absolutely mono speech, 45 sec of pan potted stereo on the voice (with EQ) 1 min of impulse convolution to emulate a speaker, a few seconds of impulses and 1 min of various reverbs effects on a voice.
Was it a joke ? Do they expect a lot of sales ?
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If some of you are still interested by demos, you can have a look here. It's about stereo localization mechanisms.
the same sample of cello (with strong artificial reverb) is played 4 times.
This primitive phase trick is about cheating our ITD process and the bandwidth of the cello is perfect for this.
But, (and maybe this is "on topic") : the phase relations between the speakers have to be considered.
joined pic : a view of the editor with the 4 samples (left channel on the top)
I don't like to make negative critics, but bentoronto can be skeptical about this demo : it's 7 mins of absolutely mono speech, 45 sec of pan potted stereo on the voice (with EQ) 1 min of impulse convolution to emulate a speaker, a few seconds of impulses and 1 min of various reverbs effects on a voice.
Was it a joke ? Do they expect a lot of sales ?
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If some of you are still interested by demos, you can have a look here. It's about stereo localization mechanisms.
the same sample of cello (with strong artificial reverb) is played 4 times.
- original track : all on the right side, this is a stereo based on levels (panned, can see it in the editor), no phase shift.
- phase shift on the right channel of -180° : the cello is always localized on the right, but maybe a little bit more behind. I don't see any big cancellation issue
- original track, but after normalization of the levels R/L : the cello is now on the center, logic...
- this same normalized track but now with the -180° shift on the right : same levels, but the cello is back on the right.
This primitive phase trick is about cheating our ITD process and the bandwidth of the cello is perfect for this.
But, (and maybe this is "on topic") : the phase relations between the speakers have to be considered.
joined pic : a view of the editor with the 4 samples (left channel on the top)
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