I believe this is overly simplified. And the effect is also related to how you hear or listen.
Hearing the practices of various musical instruments by students in various locations, one can clearly distinguish the difference in acoustics - small practice rooms, hall ways, outdoors, classrooms, music hall, (big indoor) stadium...
For example, piano sounds in a small acoustically dry room and a highly reflective big room are totally different. I don't believe it can be ignored.
Voice is just more familiar to most people. Most people don't listen.
Speaker Dave,
It is usually readily apparent that you are in a warehouse as far as sound goes. The decay times are usually very long and the slap back echo can smear everything. Can't imagine that you would need voices to notice that. Unless of course your warehouse has absorptive panel all around it!
It is usually readily apparent that you are in a warehouse as far as sound goes. The decay times are usually very long and the slap back echo can smear everything. Can't imagine that you would need voices to notice that. Unless of course your warehouse has absorptive panel all around it!
I'm not saying room acoustics are inaudible so much as certain sounds may reveal them easily and others may obscure them greatly.
Note that the target RT for modern concert halls is 2.1 to 2.4 seconds. The Predominant surface is concrete or plaster (acousticians pull their hair out when the client asks for "the warmth of wood"). Shoot off a starters pistol and you can count the whole 60 dB of decay, yet with legato strings you may never hear the hall contribution at all.
I'm not the first person to comment on this as it has been well observed before.
David S
Note that the target RT for modern concert halls is 2.1 to 2.4 seconds. The Predominant surface is concrete or plaster (acousticians pull their hair out when the client asks for "the warmth of wood"). Shoot off a starters pistol and you can count the whole 60 dB of decay, yet with legato strings you may never hear the hall contribution at all.
I'm not the first person to comment on this as it has been well observed before.
David S
Dave,
Not to belabor the differences of a warehouse and a concert hall but two very different animals there. I think we can agree that the acoustics of a concert hall are very different than a square warehouse! But that wasn't the point anyway. Just that a warehouse wouldn't be an ideal place to do much critical listening in and most people would be able to identify the sound of the inside of one.
Steven
Not to belabor the differences of a warehouse and a concert hall but two very different animals there. I think we can agree that the acoustics of a concert hall are very different than a square warehouse! But that wasn't the point anyway. Just that a warehouse wouldn't be an ideal place to do much critical listening in and most people would be able to identify the sound of the inside of one.
Steven
You will because of the effect reflections have when they arrive from different locations than the direct sound. That causes the sensation of spaciousness. Do you have the Denon CD with anechoic orchester recordings? Listen to it over headphones then play it in your warehouse. Huge difference.
True if direct sound and reverberation is first mixed together and then played back through a speaker. Not true in the case of real reverberation that is arriving at the ear from a multitude of directions.
I know they are different animals. Concert halls don't have aisles wide enough for the fork lifts!
The point remains, identifying the acoustics of a room requires an appropriate signal and is obscured by continuous and slowly changing sound. (obscured but not impossible.) Interestingly sounds and spaces have evolved to suit each other. When the Cathedrals of Europe have 4 second reverb time, then organ music becomes a slow and ponderous thing. Politicians learn to "orate" in a slow and deliberate manner to preserve inteligibility. Orchestras grew along with concert halls as romantic music evolved post classical.
Even arrival direction is little help until the sound gets percussive enough. This is why auditory thresholds are always different between speech and pink noise in all manner of tests.
David S
It should be logically apparent that two very similar tones will be perceptually closer to one single tone than two very different tones, regardless of where this difference actually comes from.
A properly explained reason would be nice, or else everyone will disregard your idea as just another unsubstantiated opinion. I would not like to see that happen.
You might be interested in this from Chris at Preservation Sound:
http://www.preservationsound.com/wp-content/uploads/2012/09/JVC_Binaural_1977.jpg
"Experimental binaural headphone system by JVC. 500-cycle crossover point; highs originate in front of the face, lows from above the ears."
No other info yet, unfortunately - I just happened to be reading Preservation Sound just after DiyAudio.
Regarding the crossover frequency: as I understand it, at low to mid frequencies, direction cues mainly come from inter-aural phase differences. At higher frequencies, the direction cues start to come from inter-aural level differences due to HRTF. So with the JVC design the low frequencies come from above the ear, but because the wavelengths are so long you get no localisation cues apart from phase differences. At mid to high frequencies HRTF comes into play, and the drivers are positioned to provide the necessary cues. I suspect these may sound a little odd with "manufactured", studio panned material, but makes sense for ambiophonic style material.
I'm tempted to try building a chair with bass generated in the vicinity of the head, and a pair of "pods" mounted on stalks out in front for mids / highs. I'm sure it has been tried before, but this is DiyAudio after all. I have the chairs and drivers, all I need is a round tuit... my aim is to build on the work that Patrick Bateman and others have done on the perception of sound source locations, and produce significant SPL without entertaining the whole neighbourhood. When I get that round tuit, I'll open a new thread.
Done,
I don't know if you have ever sat in one of the egg chairs with speakers built in/ I worked with the original creators of that concept. It was a company called Starkey Labs and the original concept was for checking hearing as they were and I think still are involved in the design and manufacturing of hearing aids. I have always wanted to recreate one of those chairs with better devices built into the shell. Perhaps that would be a good project to analyze all what we are talking about as it also has very good isolation from the outside and contains most of the sound internally.
I don't know if you have ever sat in one of the egg chairs with speakers built in/ I worked with the original creators of that concept. It was a company called Starkey Labs and the original concept was for checking hearing as they were and I think still are involved in the design and manufacturing of hearing aids. I have always wanted to recreate one of those chairs with better devices built into the shell. Perhaps that would be a good project to analyze all what we are talking about as it also has very good isolation from the outside and contains most of the sound internally.
Thanks for the link Don, that looks pretty cool. I've been inspired by the egg chairs as well. If I were living in my home country (Australia) and didn't have to worry about moving my possessions around, I'd love to make such a listening spot. Messing around with nearfield dipole bass, I think that any sensation in your body really helps move a stereo image away from the head.
What I've worried about with near field HF is all of the comb filtering from head movements. Also my fiancee and I like to cuddle up which is easier with headphones than nearfield speakers.
You can play HF quite loud without disturbing the neighbours. A Watson setup with tweeters in the farfield and the midrange nearfield might work well for satisfying SPL without sound making it through walls and with minimal comb filtering problems. It becomes very sweet spot limited but could be interesting.
It could be like CLS's setup but with the L,R moved closer and time aligned.
What I've worried about with near field HF is all of the comb filtering from head movements. Also my fiancee and I like to cuddle up which is easier with headphones than nearfield speakers.
You can play HF quite loud without disturbing the neighbours. A Watson setup with tweeters in the farfield and the midrange nearfield might work well for satisfying SPL without sound making it through walls and with minimal comb filtering problems. It becomes very sweet spot limited but could be interesting.
It could be like CLS's setup but with the L,R moved closer and time aligned.
I played with near field bass with my clone of Oliver's (2pi) Demokrit crossed various around 150-250 Hz. I used 2 bare Visaton woofers (10 and 12 inches) EQed slightly for dipole roll off.
Note that I lay on the floor for pure listening enjoyment. I don't like sitting down after working at a PC all day. I was listening with my head about 30-50 cm from the woofers on some memory foam pillows. I have to say that it worked pretty awesomely. I had used bookshelves like this in the past but this time was much better. I used REW and a mic to balance SPL. A key here, I think, is to use 2 drivers. In the nearfield, distance ratios are magnified. I feel that with 1 woofer I could localize it more easily since on turns of the head your ears get several dB differences. You can feel the pressure difference between the ears when it's off to the side. I measured a pillow length width apart along the center line of the 2 woofers, which corresponded to a double of distance in the triangle from the woofers, and saw only a 2 dB difference in the bass response. This would have been partially due to the orientation of the dipole lobes.
So with dual mono nearfield bass you can make a decent sized sweet spot, similar to that from crossing CD speakers. Concentrating on the image from the full range speakers in front of me, I could easily forget about the woofers near my head and simply enjoy the music. If a song had far too much/little bass, I shifted forward/backward.
It was great to know that I could enjoy this clean headphone like bass at a nice SPL (and miniscule distortion) without disturbing the neighbours. When I stood up, it disappeared! I'm sold on this for my fixed position home theater setup.
The next thing to try is to extend their frequency range and see how it sounds with a central tweeter in front.
Note that I lay on the floor for pure listening enjoyment. I don't like sitting down after working at a PC all day. I was listening with my head about 30-50 cm from the woofers on some memory foam pillows. I have to say that it worked pretty awesomely. I had used bookshelves like this in the past but this time was much better. I used REW and a mic to balance SPL. A key here, I think, is to use 2 drivers. In the nearfield, distance ratios are magnified. I feel that with 1 woofer I could localize it more easily since on turns of the head your ears get several dB differences. You can feel the pressure difference between the ears when it's off to the side. I measured a pillow length width apart along the center line of the 2 woofers, which corresponded to a double of distance in the triangle from the woofers, and saw only a 2 dB difference in the bass response. This would have been partially due to the orientation of the dipole lobes.
So with dual mono nearfield bass you can make a decent sized sweet spot, similar to that from crossing CD speakers. Concentrating on the image from the full range speakers in front of me, I could easily forget about the woofers near my head and simply enjoy the music. If a song had far too much/little bass, I shifted forward/backward.
It was great to know that I could enjoy this clean headphone like bass at a nice SPL (and miniscule distortion) without disturbing the neighbours. When I stood up, it disappeared! I'm sold on this for my fixed position home theater setup.
The next thing to try is to extend their frequency range and see how it sounds with a central tweeter in front.
What a refreshing change!
Someone willing to experiment as opposed relying on "he said/she said".
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