Pets can’t go wrong. They listen to stereo while laying on the floor. Have you ever tried to do the same? If so, do it again. If not, try it out.
Lay down on your back on the floor, so that your face is heading for the ceiling. Your head might be placed at the floor projection your usual sweet spot listening position in the room. And your body then should point away from the stereo basis on it’s central symmetry line, so that your feet point away from the speaker base line. Having placed yourself like this, the loudspeaker base line geometrically will appear away from the apex of your head. As if in a normal upright position, the speakers would hanging above you and pointing down at 30° left and 30° right angles.
Having you eary very close to the floor, there is practically no more floor reflection. The first reflection will be the ceiling reflection, also much weaker and coming in substantially later than usual. This alone makes you listen outside your usual psychoacoustic and room-dimensional envelope.
Then add a an upside board onto the symmetry line of the stereo basis, nearly touching the apex of your head. This board will cancel most of the inter-ear x-talk, which makes for another psychoacoustic change.
Then close your eyes, thus shutting down any visual orientation.
Doing so, you have
Still, you can further enhance the experience, because there is a drawback about this x-talk canceling board. It adds it’s own, early reflection. Therefore, I fitted a kind of deluxe-board with some PET woven acoustical absorber panels. The result then is near-breathtaking.
Therefore, here some comments and pictures about this improved xtalk-canceling board. First have a look at it's simple construction. It roughly measures 60cm x 80cm and is made of birch plywood:
The narrow side is where the head will be placed during the hearing session, the open side points to the speakers base line.
Now, how effective is it? Measurements will tell. Using a calibrated dummy head ...
... which undoubtfully was a wee bit larger than live ...
... some measurements were performed.
The results were quite conclusive:
Red and Green are the graphs for same-side stimulus and measurements.
Red is the difference between the [ right channel mic'ed on the right side ] and the [ left channel mic'ed on the left side ]. Measured "free field", without the x-talk canceller board.
Green is the same, but measured with the x-talk canceller board between the speakers and the dummy head.
Both curves hover around the zero lines and show no big differences. In the conclusion, for the direct same-side-pathways there is no big difference wheter the x-talk canceller board is placed, or wheter it is ommited.
Blue and Black are the curves of the R->L crossing acoustical pathways measurements difference.
Blue is as above the difference without the x-talk canceller board (baffle). This curve shows some "natural" spl cancellation of the crossing pathway due to the dummy head shading.
Black is the same, but with the x-talk canceller board obturating the crossing soundpath installed. It's effect is quite impressive: The damping of the board for the crossing soundpath is in the range of 10dB below 1kHz and raising well above 20dB at 10kHz.
So, the effectiveness of this x-path cancelling deluxe board is quite evident. Once from the measurement's results, and also in terms of an effect for the aformentionned soundstage.
Made you curious? Happy laying down and happy boarding, then !!! You won't probably regret it.
Lay down on your back on the floor, so that your face is heading for the ceiling. Your head might be placed at the floor projection your usual sweet spot listening position in the room. And your body then should point away from the stereo basis on it’s central symmetry line, so that your feet point away from the speaker base line. Having placed yourself like this, the loudspeaker base line geometrically will appear away from the apex of your head. As if in a normal upright position, the speakers would hanging above you and pointing down at 30° left and 30° right angles.
Having you eary very close to the floor, there is practically no more floor reflection. The first reflection will be the ceiling reflection, also much weaker and coming in substantially later than usual. This alone makes you listen outside your usual psychoacoustic and room-dimensional envelope.
Then add a an upside board onto the symmetry line of the stereo basis, nearly touching the apex of your head. This board will cancel most of the inter-ear x-talk, which makes for another psychoacoustic change.
Then close your eyes, thus shutting down any visual orientation.
Doing so, you have
- shut down acoustical info about the height of your head over ground level (no floor reflection)
- psychoacoustically changed the usual room height, or left the room altogether (ceiling reflection)
- sharpened left-right discrimination (no x-talk)
- sharpened your auditive perception in general (by closing the eyes)
- the sound seems to be coming from a very unusual direction (body related from above you)
- a maybe easier relaxation in the lying position
Still, you can further enhance the experience, because there is a drawback about this x-talk canceling board. It adds it’s own, early reflection. Therefore, I fitted a kind of deluxe-board with some PET woven acoustical absorber panels. The result then is near-breathtaking.
Therefore, here some comments and pictures about this improved xtalk-canceling board. First have a look at it's simple construction. It roughly measures 60cm x 80cm and is made of birch plywood:
The narrow side is where the head will be placed during the hearing session, the open side points to the speakers base line.
Now, how effective is it? Measurements will tell. Using a calibrated dummy head ...
... which undoubtfully was a wee bit larger than live ...
... some measurements were performed.
The results were quite conclusive:
Red and Green are the graphs for same-side stimulus and measurements.
Red is the difference between the [ right channel mic'ed on the right side ] and the [ left channel mic'ed on the left side ]. Measured "free field", without the x-talk canceller board.
Green is the same, but measured with the x-talk canceller board between the speakers and the dummy head.
Both curves hover around the zero lines and show no big differences. In the conclusion, for the direct same-side-pathways there is no big difference wheter the x-talk canceller board is placed, or wheter it is ommited.
Blue and Black are the curves of the R->L crossing acoustical pathways measurements difference.
Blue is as above the difference without the x-talk canceller board (baffle). This curve shows some "natural" spl cancellation of the crossing pathway due to the dummy head shading.
Black is the same, but with the x-talk canceller board obturating the crossing soundpath installed. It's effect is quite impressive: The damping of the board for the crossing soundpath is in the range of 10dB below 1kHz and raising well above 20dB at 10kHz.
So, the effectiveness of this x-path cancelling deluxe board is quite evident. Once from the measurement's results, and also in terms of an effect for the aformentionned soundstage.
Made you curious? Happy laying down and happy boarding, then !!! You won't probably regret it.
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Yes, certainly
.The measurements are by far not meant to be precise, because there is no need for precision here. They were performed to show the working principle of the board (black graph). And they also show the principle of the more moderate shading effect of the "head" (blue line). A bigger structure such as this jokingly used gardening bucket e.g. will lead to more low frequency shading than a smaller structure, of course. You can also measure the effect of the board without any dummy head, only by shifting the microphone laterally some cm from the speaker baseline symmetry line.
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This setup certainly is different from the usual one. But what is not very pactical about this setup? All you have to do is to move this board into your acoustic paths, lay and down to enjoy the music. And then, you can remove this board again after your relaxing hearing session. Of course, if you have the habit to smoke a cigar and drink some whiskey during your hearing sessions, or surf on your tablet while listening, then this setup definitely is not practical. Agreed.
Nice point! I did not think about this setup as a possible reference listening experience while modifying your room acoustics for best possible audio.
Yeah, about a year ago I realized I could hear transition between near and far field sound with my system. Listening closer than the transition, the audible critical distance, effect of local room to stereo image seem to reduce quite suddenly, while beyond the effect of room (early reflections) seems to be significant in relation.
I've been using the transition for this purpose, ability to change audio perspective at will to develop listening skill and to hear how for example toe in or height of speakers change sound, or how crossovers (time/phase aligment) is perceived, how different frequency bands localize differently, noticed some recordings sound better close while some on the far, and so on. Need to try your setup as well!
If you are interested in such things, try find the audible critical distance in your system and room: put mono white noise playing to get maximally strong phantom center. Assuming you have ~20m2 room with 2.4m ceiling setup speakers for 2 meter equilateral stereo listening triangle to start somewhere. Walking center normal between speakers concentrate on listening the phantom center: Starting far away, like 3-4meters away from speakers the phantom center is quite big blob, but walking closer there seems to be a distance where quite sudden transition seems to happen, phantom center gets sharp in a way, focused/localized more sharply, and sound gets more enveloping instead of being perceived fully in front. If you don't seem to notice the transition, try change toe in and size of the stereo triangle to make it more pronounced. I'm not sure how audible this is in general, you should be able to hear the "far" sound when you listen otherside of the room, and the "close" sound should happen when you are very close, like recording studio near field setup, stereo triangle of one meter or so, far away from walls if necessary. Anyway, finding the transition is the key thing here; Listening about at the transition you can lean forward or backward to change perspective and do reasoning with perception from the two.
I've been using the transition for this purpose, ability to change audio perspective at will to develop listening skill and to hear how for example toe in or height of speakers change sound, or how crossovers (time/phase aligment) is perceived, how different frequency bands localize differently, noticed some recordings sound better close while some on the far, and so on. Need to try your setup as well!
If you are interested in such things, try find the audible critical distance in your system and room: put mono white noise playing to get maximally strong phantom center. Assuming you have ~20m2 room with 2.4m ceiling setup speakers for 2 meter equilateral stereo listening triangle to start somewhere. Walking center normal between speakers concentrate on listening the phantom center: Starting far away, like 3-4meters away from speakers the phantom center is quite big blob, but walking closer there seems to be a distance where quite sudden transition seems to happen, phantom center gets sharp in a way, focused/localized more sharply, and sound gets more enveloping instead of being perceived fully in front. If you don't seem to notice the transition, try change toe in and size of the stereo triangle to make it more pronounced. I'm not sure how audible this is in general, you should be able to hear the "far" sound when you listen otherside of the room, and the "close" sound should happen when you are very close, like recording studio near field setup, stereo triangle of one meter or so, far away from walls if necessary. Anyway, finding the transition is the key thing here; Listening about at the transition you can lean forward or backward to change perspective and do reasoning with perception from the two.
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