Not if you look at distance over time
50hz traveling 1m vs 2m....there will be more oscillations to reach 2m
Thx b_force,
yep, good paper, (the same one fluid linked.)
Paper seems to be more about thresholds of audibility, including thresholds for bodily sensation / integration with hearing.
what I'd like to find, is research regarding how long does it take the ear to resolve a particular frequency...
Like in digital sampling we know it takes a 1 cycle period to resolve frequency.
I'm wondering about the ears resolution ...how many cycles / how long, does it take for the ear/brain to resolve frequency.....and if that # of cycles/time varies by frequency.
Good article.
I thought these words in the Abstract first paragraph were interesting – “…the tonal sensation ceases around 20 Hz, and below 10 Hz it is possible to perceive the single cycles of the sound.”.
It seems that low frequency perception is tonal, tactile, dependent on waveform character, dependent on an individual’s ear compression threshold, for starters…
Possible Questions –
1. How many cycles are required in a bass tone burst, above 20Hz, to recognize tone?
2. Would that perceived single cycle below 10Hz be considered tactile? Is it in the reverberant field because of the wavelength relationship to the smaller room?
3. Can we sense directness of sound based on tactile sensation vs tonal sensation?
4. Does the tactile sensation we feel have anything to do with VLF? I think most of any tactile sensation comes from about 100-400 Hz.
5. What degree of change from sinusoidal impacts perception?
I think enormous levels of subbass in small rooms reduces overall intelligibility rather than add anything to the mix, and I use 24” subwoofers. Air compression in the room does strange things.
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Not sure what you are trying to say.
If you change your MLP from Xm to Ym, there will there be no more oscillations coming from a recording. The only thing that will change is the delay time of arrival; from X to Y.
While the current 'new normal' could have been foreseen as early as 2015, it remains somewhat frustrating to see the massive price increases for drivers over the past 2 years.
These increases mainly apply to the western world, because prices are still very reasonable in Asia. This of course holds for drivers that are manufactured locally.
I came across a number of interesting drivers from an Asian manufacturer that has been around for 40 years. The parameters deviate from what we are used to, which offers interesting application possibilities for hi-fi.
Attached is a sim of 2x 12" (parallel) in a 180 L BR cab. This driver combines a high BL with a modest Mms and relatively low Fs, resulting in a fairly high Qts. This seems to be an excellent driver for use with low power amps.
Oh, and the price?
€50... for a pair.
These increases mainly apply to the western world, because prices are still very reasonable in Asia. This of course holds for drivers that are manufactured locally.
I came across a number of interesting drivers from an Asian manufacturer that has been around for 40 years. The parameters deviate from what we are used to, which offers interesting application possibilities for hi-fi.
Attached is a sim of 2x 12" (parallel) in a 180 L BR cab. This driver combines a high BL with a modest Mms and relatively low Fs, resulting in a fairly high Qts. This seems to be an excellent driver for use with low power amps.
Oh, and the price?
€50... for a pair.
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Probably the most coherent thing I've come across on this topic is diffuse vs modal.
First, I agree with @tmuikku that pressure is the basis of the experience that I'm investigating. What I am leaning towards, is that the pressure differences between the high spl in a room vs anechoic, is perceivably different to touch part of the experience.
I think that we can sense pressure coming from all around as in mode resonating vs pressure coming from the direction of the driver.
The more diffuse the signal is the more concentrated all the pressure will be, coming from the direction of the loudspeakers.
The face of the radiator will act as a plane of point sources...a result of cancellation and Summing
Its just a matter of phase from the all the points combined creating a singular wave. As seen here if we spread the 4 point out.
the omnidirectional energy dispersion will happen at any given coordinate on the face if the radiator surface plane.... how that energy interacts creates directivity.... in the omnidirectional spectrum for the driver size, there is no phase cancellations to cause directivity thus omnidirectional output... but in my diaphragm all I am showing are the paths that direct sound will follow, to the listening point. There's an increase in these paths, with a larger radiator, in the omnidirectional spectrum of the radiator
The way some describe it, it sounds like they are suggesting that direct sound to the listener only happens at one singular path, to the listening point and I'm pretty sure that's not it. And Its not just the ear, everything in the path of radiation will have the same increase.... Increasing Radiation Area increase the Direct Sound portion of the summed spl of Direct+Indirect.
"Critical distance is the distance at which the reverberant sound field is equal in level to the direct sound from a sound source. " Heres another take on what I am saying; As you increase Radiation surface area....The critical distance will move further away from the Speaker, even in the omnidirectional spectrum.
Quite true, although overkill seems to be the norm these days, both for hi-fi and club sound. Too much bass is both boring and exhausting.
It kills the music, especially if implemented poorly.
Integration is the keyword, and relatively few manufacturers succeed in developing a truly homogeneous sounding system, even though many think they've found columbus' egg through all kinds of 'science' based high-tech solutions.
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I wonder if there is actually a simple answer to that question, these are useful though
https://people.finearts.uvic.ca/~as...ogy of Hearing by Brian Moore 6th Edition.pdf
http://hyperphysics.phy-astr.gsu.edu/hbase/Sound/timbre.html
https://link.springer.com/content/pdf/10.3758/BF03212841.pdf
https://phys.org/news/2013-02-human-fourier-uncertainty-principle.html
This one has an interesting little test in it
https://ccrma.stanford.edu/~malcolm/correlograms/index.html?29 Pitch Salience And Tone Duration.html
Hi, yeah you are correct, every point on the transducer surface works as source of sound and emits "unit of sound" which propagates to all directions. Together they interfere and make directivity pattern, rather easily measured and plotted. Low frequencies sum together and you get pretty much omni pattern, very low directivity index. High enough frequency and beaming happens, high directivity index, "units of sound" sum in phase only on-axis and you get your intensity. If you are looking at single round transducer you can predict the directivity just by knowing the diameter. Directivity "shape" is exactly the same for big and small ideal transducer only frequency changes where the pattern happens, transition from very long wavelength omni radiation to short wavelength beaming, its ratio of physical size to wavelength.
Basically yeah, bigger transducer give more sound towards listening position as in your pictures and logic, more "units of sound" bubbles which the listening position sooner or later. Small transducer can (possibly) give as much just crank the amp louder, increase excursion to get same volume displacement. Its the SPL reading in the end. Difference between the big and small transducer is their directivity and what you need to be concerned is directivity of the system as whole, and how it works with the application you have so that you are within the critical distance, if thats what you are after. And get high or low early reflections sooner or later and so and so late reverberation in the room. There is some standards for sound work I believe, ITU something but at least hobbyists can do what ever they fancy, or happen to get 🙂
So, its about directivity, and how you utilize it. First, you need to know what you are doing, then plan what kind of directivity might work in your space with practical positioning, then figure out what kind of speaker system you need to make the directivity happen. If you need directivity to very low frequency its gonna be huge array / horn. Or what ever, some want as much as possible, omni stuff. Don't forget diffraction, it makes secondary sound sources like reflections do, or "units of sound", but kind of worse as they are not similar to on-axis sound but different spectra because its wavelength dependent phenomenon, and have some short and usually varying delay to them, and opposite polarity, yuck.
Can't beat headphones 😉
edit. standard I had in mind is probably this ITU-R BS 1116-1 but there might be others, and probably is. Good thing about standards is that there are many 😀
eidt 2. yeah EBU tech 3276 https://tech.ebu.ch/docs/tech/tech3276.pdf
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Making your own terms up must be contagious 🙂
Not at 50Hz where the response is omnidirectional which is where this all started. A long way from the ray acoustics region where that sort of thing makes sense.
Yeah, communication is hard, gotta try get similar lingo to increase chances of delivery 😀
Silly math example for 50Hz beaming to get some scale on things: If 15" driver beams enough at 2kHz, this is our target directivity which we'd like to have at 50Hz. What size transducer we'd need to get the same directivity 50hz as 15" has at 2kHz?
~2kHz wavelength is ~7", 50Hz wavelength is ~270", to get transducer size solve x: 15" / 7" = x / 270" => ~578" diameter transducer. That doesn't exists so an array of 39x 15" drivers it is, but that would make only horizontal or vertical directivity. Make ~39x39 array to get both, 1500x 15" drivers 😀 well, probably some other means would be more practical, like having drivers arrayed with 1/4 wl gaps and still get roughly similar directivity up to 50Hz and then crossover to another system for frequencies above, or what ever, only ~10x10 array then.
Luckily we are in a room and the 50Hz array won't fit in so we can stop dreaming and use even more practical system. Taking account how the low frequencies are perceived and how they behave in room one can optimize the system quite a lot. fluid has just posted some material how lows are perceived and Geddes has his subwoofer system pretty nicely explained and most likely something what one needs to have well perceived 50Hz, as long as we are in a room.
Silly math example for 50Hz beaming to get some scale on things: If 15" driver beams enough at 2kHz, this is our target directivity which we'd like to have at 50Hz. What size transducer we'd need to get the same directivity 50hz as 15" has at 2kHz?
~2kHz wavelength is ~7", 50Hz wavelength is ~270", to get transducer size solve x: 15" / 7" = x / 270" => ~578" diameter transducer. That doesn't exists so an array of 39x 15" drivers it is, but that would make only horizontal or vertical directivity. Make ~39x39 array to get both, 1500x 15" drivers 😀 well, probably some other means would be more practical, like having drivers arrayed with 1/4 wl gaps and still get roughly similar directivity up to 50Hz and then crossover to another system for frequencies above, or what ever, only ~10x10 array then.
Luckily we are in a room and the 50Hz array won't fit in so we can stop dreaming and use even more practical system. Taking account how the low frequencies are perceived and how they behave in room one can optimize the system quite a lot. fluid has just posted some material how lows are perceived and Geddes has his subwoofer system pretty nicely explained and most likely something what one needs to have well perceived 50Hz, as long as we are in a room.
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From fluid links, quick skim through, there was some notion that when tone duration is short it is perceived as click and its possible to detect pitch with certain time interval. The last link reads that hearing two full cycles of sine tone should give correct pitch perception. I'm on a shaky ground with the info here but just making an example for camplo. He spoke about oscillations and direct energy, perhaps meaning that he want the "direct energy" to be perceived before there is secondary sounds like reflections come in and make their effect on perception?
Ok, a ssuming we'd want to hear 50Hz "direct energy" long enough the pitch is perceived, assuming it needs to be two cycles. We'd want to have two cycles at 50Hz before reflections arrive. 50Hz duration is 20ms and two makes 40ms, which means we'd need to push boundaries far enough for reflections to arrive 40ms later than direct sound. This is ~13.7 meters of path length difference. So, our room should be quite big to achieve this, boundaries >6 meters out from speaker and listener.
On the other hand, listening situation standard I linked earlier as well as texts by Toole and Geddes, perhaps others, indicate much shorter early reflection delay is fine enough, minimum being like 10ms (two cycles of 200Hz btw) and preferably more. So, while all of this is interesting to think about perhaps concentrate efforts whats practical with current room, or go out shopping for bigger one 🙂
Ok, a ssuming we'd want to hear 50Hz "direct energy" long enough the pitch is perceived, assuming it needs to be two cycles. We'd want to have two cycles at 50Hz before reflections arrive. 50Hz duration is 20ms and two makes 40ms, which means we'd need to push boundaries far enough for reflections to arrive 40ms later than direct sound. This is ~13.7 meters of path length difference. So, our room should be quite big to achieve this, boundaries >6 meters out from speaker and listener.
On the other hand, listening situation standard I linked earlier as well as texts by Toole and Geddes, perhaps others, indicate much shorter early reflection delay is fine enough, minimum being like 10ms (two cycles of 200Hz btw) and preferably more. So, while all of this is interesting to think about perhaps concentrate efforts whats practical with current room, or go out shopping for bigger one 🙂
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Now we only need to simulate a big driver vs a small driver in the same room that has the right size, you choose the distance we need 🙂.
Let's see if there's a difference in room interaction between those two scenarios. You know, based on this theory:
If it really works like camplo indicates, wouldn't the bigger driver have a bigger problem to stay away from room boundaries, purely based on size alone 😀.
Just because you want something to be true doesn't make it true... Now if you take more sources/drivers, that would change things up a bit...
Let's see if there's a difference in room interaction between those two scenarios. You know, based on this theory:
If it really works like camplo indicates, wouldn't the bigger driver have a bigger problem to stay away from room boundaries, purely based on size alone 😀.
Just because you want something to be true doesn't make it true... Now if you take more sources/drivers, that would change things up a bit...
Thank you fluid, very generous reading list 🙂
Plenty to study...
I've noticed how a click-turns-into-tone, like in the last link you posted, when wavelet burst tests on drivers .
Only digging into the first paper so far, ...it sure does seem like the ear is going to resolve low frequencies faster than taking several periods...but yikes, so much to learn here....
Yes it does, you just don't understand my logic... a larger radiator gives a large volume of pressurized air... you are focused on spl, I am focused on volume. The volume increase is that of direct sound. Thats a fact
As for calling direct sound, direct energy...sound is energy, goof ball ⚽️
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Speaking of Volume, we can organize the final SPl in a room as a sum of Direct and Indirect Sound.... The volume of Direct Sound increases with Radiation area, in the omnidirectional spectrum.
2x Faital Pro 12PR320 16 Ohm in the same cabinet...
Similar result albeit with lower sensitivity and marginally worse GD.
However, a pair (with discount) costs 400 euros more.
