Hi all,
Any engineers or tinkerers that have some input on the following?
Looking at a repeatable way to measure various metrics that can relate to tactile response from a distance and specifically not from a vibrating platform, but rather from various speaker designs. It seems really challenging actually to get a reliable way to measure something remotely as sensitive as how we perceive tactile response from SPL and other factors. I already have been able to reliably measure acceleration changes from my pneumatic platform as it bounces up and down to relate it to tactile response. But now I want to get more specific with speakers at a distance.
I'm trying to make something crude but functional for this, just to satisfy my own curiosity. I can measure acceleration of my pneumatic platform and that works well. But I'm interested in another way to measure speaker source tactile response from a distance, of say 2 meters, so its repeatable. I would like to be able to set an SPL level at a frequency or range, so that it can be repeated with different speakers so that the SPL at the frequency is the same (or very very similar) and then the differences can start to be examined.
I was thinking of building a diaphragm or drum. Nothing big. A small frame with a thin material like paper between the frame, held rigid but not immobile. Small enough dimensions to resonate primarily at higher frequencies, but large enough to have resolution and sensitivity to capture pressure changes and other things as waves impact it. On the diaphragm I will attach a sensor that captures acceleration, angle changes and angular velocity changes. This is not a lab level instrument, just a fun little sensor that does that.
My primary curiosity is to see if I can capture any meaningful differences between SPL and anything else. For example, if SPL at a frequency is matched, is there a tactile response difference from a single large driver with higher excursion, vs many smaller drivers with less excursion from a distance. Is there a tactile response difference from a driver at a frequency and SPL compared to a horn or port or slot with air velocity involved at the same frequency and SPL at the same distance? Just things like that, that I'm curious about. Maybe its pointless. But I'm curious. I'm not sure if I even have an instrument to capture this, so I'm just throwing around ideas. Any thoughts or help on how to capture something like that would be appreciated with simple instruments.
I did a prototype and it seems to capture some data. It was no capturing acceleration hardly at all (minimal). But it was capturing angular velocity shifts in X and Y axis. Mostly in X axis (which makes sense I suppose, as the wave propagated towards it from that plane and passed over it). But I had other frequencies that excited it in the Y axis. So then that means perhaps the frame of the diaphragm/drum was causing problems. So, many things to figure out to eliminate to improve control and remove random and bias.
Just thinking out loud. Any input appreciated.
Very best,
Any engineers or tinkerers that have some input on the following?
Looking at a repeatable way to measure various metrics that can relate to tactile response from a distance and specifically not from a vibrating platform, but rather from various speaker designs. It seems really challenging actually to get a reliable way to measure something remotely as sensitive as how we perceive tactile response from SPL and other factors. I already have been able to reliably measure acceleration changes from my pneumatic platform as it bounces up and down to relate it to tactile response. But now I want to get more specific with speakers at a distance.
I'm trying to make something crude but functional for this, just to satisfy my own curiosity. I can measure acceleration of my pneumatic platform and that works well. But I'm interested in another way to measure speaker source tactile response from a distance, of say 2 meters, so its repeatable. I would like to be able to set an SPL level at a frequency or range, so that it can be repeated with different speakers so that the SPL at the frequency is the same (or very very similar) and then the differences can start to be examined.
I was thinking of building a diaphragm or drum. Nothing big. A small frame with a thin material like paper between the frame, held rigid but not immobile. Small enough dimensions to resonate primarily at higher frequencies, but large enough to have resolution and sensitivity to capture pressure changes and other things as waves impact it. On the diaphragm I will attach a sensor that captures acceleration, angle changes and angular velocity changes. This is not a lab level instrument, just a fun little sensor that does that.
My primary curiosity is to see if I can capture any meaningful differences between SPL and anything else. For example, if SPL at a frequency is matched, is there a tactile response difference from a single large driver with higher excursion, vs many smaller drivers with less excursion from a distance. Is there a tactile response difference from a driver at a frequency and SPL compared to a horn or port or slot with air velocity involved at the same frequency and SPL at the same distance? Just things like that, that I'm curious about. Maybe its pointless. But I'm curious. I'm not sure if I even have an instrument to capture this, so I'm just throwing around ideas. Any thoughts or help on how to capture something like that would be appreciated with simple instruments.
I did a prototype and it seems to capture some data. It was no capturing acceleration hardly at all (minimal). But it was capturing angular velocity shifts in X and Y axis. Mostly in X axis (which makes sense I suppose, as the wave propagated towards it from that plane and passed over it). But I had other frequencies that excited it in the Y axis. So then that means perhaps the frame of the diaphragm/drum was causing problems. So, many things to figure out to eliminate to improve control and remove random and bias.
Just thinking out loud. Any input appreciated.
Very best,
Specifically subwoofers; I generally measure tactile response via acceleration on my tactile response platform which is on pneumatic suspension and very bouyant.
I'm looking to find a way, if I can, capture a metric of some kind that can correlate to what I feel in terms of tactile response from various subwoofer designs, so the focus is going to be low frequency bandwidth, like 10hz to 200hz at specific frequencies and SPL levels so I can have a comparison to things. I have a sensor I use that measure acceleration, angle change and angular velocity. I've been able to use acceleration on the platform. And I've been able to get angular velocity changes from SPL from a sub at distance on a diaphgram that's sensitive (like a drum) from 10hz to about 60hz (nothing above that though). So I'm just looking for ideas if anything is possible, to try.
My primary curiosity is seeing if there's a measurable difference between a single large driver (18" for example) at high excursion vs several smaller drivers at lower excursion working together at the same distance and same SPL, if the tactile response can be measured to be the same or differently. Subjectively I feel differences, but I'd like to find a way to measure something to correlate. Likewise, I'd like to see if there's a measurable different in the effect made by a traditional driver vs a horn/port/slot with higher air velocities involved and if they matter for this or not.
So any ideas on how I could measure this would be appreciated, if it's possible outside of a lab without super costly instruments.
Very best,
Have I misunderstood.. I was thinking of being able to reproduce the sound and proper feel of a performer tapping their foot or knocking on the soundboard of a guitar, hearing a drumstick touch the head, or a performer bumping the mic or stand.
It's just that the frequency range may be above where most subs are.
It's just that the frequency range may be above where most subs are.
Hrm,
I'm trying to find a way to correlate a measurable parameter at a nominal distance, say 2 meters, that correlates to the tactile response we feel with audio and specifically targeting lower frequencies like infrasonic, sub bass and bass. That chest thump you feel with a kick drum. Is it just SPL? Or is there more to it? Is it different from different designs with the same SPL at the same distance? I'm just curious and want to see if there's a difference. Will an array of small drivers with less excursion each, producing 20hz at 2 meters at 100db SPL feel the same as 1 driver at high excursion producing 20hz at 2 meter at 100db SPL? And if so, what's the difference? Hopefully that explains better what I'm trying to see if it's possible to measure.
Very best,
Right. Sound can produce resonance in body parts. Some adults may be a wavelength tall at somewhere around a couple of hundred Hz. A little higher and you could see a half wavelength alternating across your torso.
Measuring it comes down to the normal methods.
It's like the way we become less sensitive to sensing direction as the wavelength becomes comparable to the distance between our ears.
Measuring it comes down to the normal methods.
If 100dB is your goal and the small drivers have achieved it, the discussion of excursion is moot. Chances are that they are all spaced within 1/4 wavelength at 20Hz which tells me they'd behave near the same. That length is also larger than our body and we tend not to be able to sense much difference there anyway.
It's like the way we become less sensitive to sensing direction as the wavelength becomes comparable to the distance between our ears.
So would you say that tactile response from a speaker is basically just SPL?
There's no difference if the SPL is the same at 20hz if it comes from a big driver vs small drivers if SPL matched? No difference if it a traditional cone piston vs a port or slot or horn as a direct radiator? Excursion has no influence (ie acceleration from a large driver moving a far distance, compared to smaller drivers with less excursion moving less distance in the same time)?
I tend to see a lot of subjective comments about a big driver hitting harder, or having more impact, but then I wonder, why? Is it just SPL? Or is there something else to it that imparts more of a feeling than just SPL alone? I'm curious about this. Maybe it's all bias and it's all the same and it's just not real and SPL is SPL and you feel it the same no matter the source type or method?
Very best,
It has to be because sound fundamentally propagates in waves displaying pressure and velocity like you'll see voltage and current used in electronics.
One difference might come down to modal effects if your body is being pressured evenly or if a pressure gradient exists due to the fact you're sitting at a node.. but I'm saying this without evidence, just food for thought.
Not if all else is equal. One example of how they might not be is when an array is created large enough to evoke directivity. Even then each case is different and you may not necessarily notice a difference.
Looking at a sine wave means we are ignoring phase/group delay, so no difference.
No, because it adds up the same when they are spaced close enough, and when set to produce the same SPL).
However in some cases harmonic distortion could cause a subjective difference, even though it's not necessarily of primary significance.. but people have reported cases where it gives an impression along the lines you're talking about.
As long as you've taken care of handling the levels though, you'll soon find there are more important things to concern yourself with.
Does this take into account that larger drivers are often mounted on larger baffles? Small baffles have greater room interactions that make placement more critical due to the risk of room mode peaks and dips. Resonances can remove vital harmonics from the presentation.
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Thanks,
Found some more info here:
https://data-bass.ipbhost.com/topic/404-understanding-and-optimizing-tactile-feedback/
Lots of good info here I think. I"m in way over my head.
But, concepts like the velocity of things and intensity along with the actual pressure indicating and measuring differences is there and showed differences. That said, this is more than I'm willing to get into for measurements. So bottom line from this info is I can't measure it really the way I want to. We're ultra sensitive and an instrument to do the same outside of a lab would require a complex human dummy with sensors all over it, etc.
So, basically I can't.
Very best,
Found some more info here:
https://data-bass.ipbhost.com/topic/404-understanding-and-optimizing-tactile-feedback/
Lots of good info here I think. I"m in way over my head.
But, concepts like the velocity of things and intensity along with the actual pressure indicating and measuring differences is there and showed differences. That said, this is more than I'm willing to get into for measurements. So bottom line from this info is I can't measure it really the way I want to. We're ultra sensitive and an instrument to do the same outside of a lab would require a complex human dummy with sensors all over it, etc.
So, basically I can't.
Very best,
My understanding is that we feel those things in different parts of our body. I'm not seeing how that will correlate to subjective feeling.
My take away is that intensity and velocity will reduce with distance based on the medium, so we feel less farther away with more things in the way. And this part of it is reduced at a greater degree than the pressure wave is, unobstructed, so we get more from the SPL at distance. If we are very close, we get more of the velocity and intensity and pressure together so we can feel more for less SPL, in theory any ways.
Those things are too difficult for me to just measure apparently, so I just needed to know if its possible or not. And it's really not, without a lab setting apparently, and an instrument capable of this stuff which I don't have access to.
It seems tactile response is far more complicated than just SPL and way more difficult to measure than sound parameters on their own. That seems to correlate with the near zero amount of measurements out there related to it in the amateur/enthusiast realm.
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I'm just trying to find a way to understand from self-measurements why I can feel a difference between two designs, if the frequency and SPL are matched at the same distance in the same position in a room. The design and operation difference being what I'm looking at, drivers, vs ports, vs excursion and driver count differences, operating differently to produce the same SPL at the same distance. They feel different. I can't explain why. So I'm just curious and looking to see if it's something that can be measured to explain a little.
4 x 12" sealed sub:
For the same frequency & SPL, this has more per-driver-excursion and no air velocity component related to a slot or vent.
8 x 12" open baffle with slot loading (opposite side) sub:
For the same frequency and SPL, these drivers have less excursion per driver. There's a slot cavity for each pair of drivers with an air velocity component (albeit a small component but its different none the less). I feel this one more at the same SPL at the same distance at the same frequency than above. Yet it has less per driver excursion and some air velocity from slots. So there's something else other than just pure SPL that I'm feeling.
Same position in the room. Same distance. Same frequency and SPL matched. They feel different. I'm just trying to see if I can measure why. Maybe that's not possible. I'm not trying to reinvent the wheel. Just trying to understand what other than SPL matters for tactile response.
Very best,
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