As we know, when "pushed" beyond certain limits, all audio components begin to present distortions which detract from the listening experience. This has the character of being non-linear, that is, things are OK up to a certain point, beyond which all h*** breaks loose.
Does the very rooms we put our audio transducers into behave in a similar way? I'd like to think there's SPLs below which room aspects dont get excited - or so excited that they turn the resultant sound to mud - and need to be treated somehow if listening at those SPLs are to be enjoyable.
I'm wondering if for a given untreated room size, there's a practical SPL limit (or range, that depends on specific dimensions of the volume) that's one of these "iron law" things. How does that limit follow room volume, from infinity (speakers outside at a cliff's edge) to a study-closet with a computer screen / speakers.
I'm wondering if one could measure SPL and immediately judge "Too loud for the (untreated) room volume / dimensions". "Stay below this level and it'll sound a lot better".
Of course what we want is better sound w/o any limitation on the SPL energy we throw into the listening environment. I'm guessing the best we can do is work on the issue (moving toward anechoic) with the intent to raise that level some, understanding there's only so much that can be done within a particular volume of listening space.
Does the very rooms we put our audio transducers into behave in a similar way? I'd like to think there's SPLs below which room aspects dont get excited - or so excited that they turn the resultant sound to mud - and need to be treated somehow if listening at those SPLs are to be enjoyable.
I'm wondering if for a given untreated room size, there's a practical SPL limit (or range, that depends on specific dimensions of the volume) that's one of these "iron law" things. How does that limit follow room volume, from infinity (speakers outside at a cliff's edge) to a study-closet with a computer screen / speakers.
I'm wondering if one could measure SPL and immediately judge "Too loud for the (untreated) room volume / dimensions". "Stay below this level and it'll sound a lot better".
Of course what we want is better sound w/o any limitation on the SPL energy we throw into the listening environment. I'm guessing the best we can do is work on the issue (moving toward anechoic) with the intent to raise that level some, understanding there's only so much that can be done within a particular volume of listening space.
That’s going to be a widely varying set of numbers, given personal preference, sensitivity/numbness to certain frequencies due to age/exposure etc.
I generally limit my listening to just under 90 dB, although most of the time is around 75.
An interesting experiment is to use an an app on your phone to watch the lower frequencies cease to increase as the volume is turned up, and how the kids and higher frequencies begin to increase, along with usually a loss of clarity.
I generally limit my listening to just under 90 dB, although most of the time is around 75.
An interesting experiment is to use an an app on your phone to watch the lower frequencies cease to increase as the volume is turned up, and how the kids and higher frequencies begin to increase, along with usually a loss of clarity.
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Yes they do. But only at very high sound pressure levels, way beyond levels that will cause undurable pain and permanent hearing loss. The main factor here is the way air acts as a linear spring due to even high variations in air pressure (Hooke's law). And possible nonlinear behavior of room boundaries hardly influence the sound pressure present in a room.
One consideration is that your hearing itself will start to distort severely at certain sound pressure levels. That effect is easily notable with pulse-like signals. Or music played (too) loud.
Another point is that hearing sensitivity not only changes with frequency but also with loudness. Music played loud is perceived (very) differently from the same played at low levels. Those two effects might have fooled you.
Yes and no. It's not so much an SPL problem as it is a reverberation time problem, along with the type of music (or other sounds) being played. Fundamentally, the main problem is "masking". This becomes intrusive when the reverberation time of the room is longer than what is appropriate for the type of music being played, and begins to mask details in the music. For good articulation of very fast musical runs (for example, allegro, presto and vivace Baroque and Classical music), a shorter RT60 is preferred, while for the big orchestral pieces of the Romantic period, a longer RT60 is preferred. Clearly, I'm generalizing with regard to the music styles, but the idea is that we don't want to "muddy the music" and lose detail with excessive reverberation.
Thanks, I appreciate reading these replies.
I'm looking for the source of the "masking" (for lack of a better term) as SPL increases. Certainly the usual suspects are into play then (strain on amplifier, speakers, ears, etc).
My question ponders if there's a limit (that is common audio knowledge) on how much sound you can push into an ordinary person-accommodating volume before sonic details are lost to the physics of the place.
Trouble is, I've no experience with a perfect stereo system in a perfect room - so I cant tell where the ear-based SPL-muddy threshold begins - a situation that assumes all else is the best you can do. Certainly it seems with age this is at some lower point, but that's about all I can say.
I suppose I'm looking for an "of course it sounds like a mess - too loud for your room dimensions - ANY system at that SPL level in there will pretty much get you the same muddy perception. Short answer: Turn it down".
Another way to look at it, can a given system still play clearly at higher SPL when the room is completely eliminated, i.e. outdoors?
Another curiosity; do fully enclosed speakers play louder without the "muddy the music" effect, vs a dipole?
Thanks!
I'm looking for the source of the "masking" (for lack of a better term) as SPL increases. Certainly the usual suspects are into play then (strain on amplifier, speakers, ears, etc).
My question ponders if there's a limit (that is common audio knowledge) on how much sound you can push into an ordinary person-accommodating volume before sonic details are lost to the physics of the place.
Trouble is, I've no experience with a perfect stereo system in a perfect room - so I cant tell where the ear-based SPL-muddy threshold begins - a situation that assumes all else is the best you can do. Certainly it seems with age this is at some lower point, but that's about all I can say.
I suppose I'm looking for an "of course it sounds like a mess - too loud for your room dimensions - ANY system at that SPL level in there will pretty much get you the same muddy perception. Short answer: Turn it down".
Another way to look at it, can a given system still play clearly at higher SPL when the room is completely eliminated, i.e. outdoors?
Another curiosity; do fully enclosed speakers play louder without the "muddy the music" effect, vs a dipole?
Thanks!
A system operated within the limits will measure the same as you turn it up, with slowly rising THD. There's no effect that suddenly jumps into play once some threshold is reached.
A very powerful system can put out enough SPL to sound like a mess, even with the same linear frequency response and low distortion.
As SPL increases, the direct-to-reverb ratio does not change, but I suspect that our interpretation does: if you clap quietly in a room, you only hear the clap. Clap louder, and you'll hear a series of reflections, too.
Chris
PS - Cross-posted with Pano. Never heard of "powering through the room".
A very powerful system can put out enough SPL to sound like a mess, even with the same linear frequency response and low distortion.
As SPL increases, the direct-to-reverb ratio does not change, but I suspect that our interpretation does: if you clap quietly in a room, you only hear the clap. Clap louder, and you'll hear a series of reflections, too.
Chris
PS - Cross-posted with Pano. Never heard of "powering through the room".
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What Markbakk said: any SPL enough to shake twist and bend room walls, floor and any reasonable roof (tin roofs exempted) into a non linear zone (beyond Young Modulus´ constraints) will be way beyond eardrum destruction.
I´m not talking about resonance by itself which may very well happen within linear response boundaries.
I´m not talking about resonance by itself which may very well happen within linear response boundaries.
The "source" of the masking to which I referred in my earlier post is the reverberant field. This phenomenon is well-understood.
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There are a lot of ideas in "pro" sound. Some of them are total BS. This is one.
Edit: "Pro sound" in general means "not home stereo". This doesn't mean that every pro sound "audio engineer" has a clue about what they're doing. More often than not, they don't.
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Asking in ignorance as well -- how many normal objects (or building construction for that matter) have a nonlinear excitation pattern? I.e. don't start vibrating until a certain amount of energy is present (or it gets shunted into certain pathways).
In normal language (I've been doing too much thinking with my work lately), is the room response actually a linear phenomenon? Or does it change with level? Rather than being linear in response with a nonlinear perception.
In normal language (I've been doing too much thinking with my work lately), is the room response actually a linear phenomenon? Or does it change with level? Rather than being linear in response with a nonlinear perception.
I think materials have to show nonelastic deformation in order to behave nonlinear when reflecting sound. But it is irrelevant. Define 'distortion' in acoustics. Any reflected sound added to the sound originating from the source means distortion. Whether linear or not.
The most likely cause of this phenomenon has been described already. The hearing sense is a complex mechanism. Not trained to listening (music) sources in a room, but to hunt, avoid being hunted and to communicate with others. It cannot deal with the complex sound field in enclosed spaces.
The most likely cause of this phenomenon has been described already. The hearing sense is a complex mechanism. Not trained to listening (music) sources in a room, but to hunt, avoid being hunted and to communicate with others. It cannot deal with the complex sound field in enclosed spaces.
Until things start rattling (which effectively adds a whole series of harmonic distortion), yes, I'd expect the room response to be linear.
Is there any reason it wouldn't be?
FWIW I ran a load of sweeps through a Faital 10HX230 and found that the frequency response started changing at very high levels (70v RMS sweep, resulting in approx 125dB@1m) with an associated distortion rise - those power levels are certainly abusive.
Chris
Chris -- thanks for the info. I asked out of ignorance (no agenda!) and was hoping someone might have measured room response at different levels. My line of thinking was that there are plenty of examples of materials/objects/systems that require a critical threshold before a mode is excited/coupled rather than shunted. There's also modal nonlinearities at high stress/strain but that's more than likely a bit loud.
To what extent any of this is happening at domestic levels, I don't know.
As an acoustic fan of various spaces, I find room acoustics can be decent at one volume level (say 1/8 W average, 70 W peak) and totally inadequate to stop standing waves at higher powers. Standing waves can totally mess up a hifi listening experience. Such room treatments as carpet, book & record cases full of product, urethane stuffed furniture, drapes, wood furniture, can flatten out the curve in my average room at low levels I usually use. At 20 or 30 db higher, one would have to install urethane bat sound control to stop the reflections off plaster walls that excite standing waves. Of course standing waves are peaks in the listening response not present in the sound source.
In another type venue, I've been working with a retired 72 year old pipe organ estimator/salesman/installer/voicer. The pipe organ is installed and "voiced" to sound good in the room in which it was originally fitted to. Certain denominations where the temporary occupant of the ministerial position has full power and answers to no local committee, the sound of the room often gets radically destroyed by alterations. Carpet gets added or deleted, wall hangings (tapestry) get installed or removed, wood paneling is installed over brick or stone or removed. Ceiling treatment changes are rare but do occur. All these room changes radically affect the balance of an organ, and many can seriously destroy the art of a million dollar instrument. The rich person financing an installation can also have some very strange ideas not consonant with mainstream art at the time. My co-worker tells many tales.
In another type venue, I've been working with a retired 72 year old pipe organ estimator/salesman/installer/voicer. The pipe organ is installed and "voiced" to sound good in the room in which it was originally fitted to. Certain denominations where the temporary occupant of the ministerial position has full power and answers to no local committee, the sound of the room often gets radically destroyed by alterations. Carpet gets added or deleted, wall hangings (tapestry) get installed or removed, wood paneling is installed over brick or stone or removed. Ceiling treatment changes are rare but do occur. All these room changes radically affect the balance of an organ, and many can seriously destroy the art of a million dollar instrument. The rich person financing an installation can also have some very strange ideas not consonant with mainstream art at the time. My co-worker tells many tales.
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I have some experience with psychoacoustics, and would be very interested in reading your thoughts/explanation of why that approach "works".
I haven't made a thorough investigation of the effect, as that would be rather hard to do.
But from my experience I would say equal loudness curves, along with compression and distortion in the middle ear. It's well documented that pitch (and I think rhythm) get herder to discern at high SPL. Perhaps our abilities to hear room problems get swamped at high SPL.
As I said, it's not pretty but it works. Sometimes it's better than the awful acoustics we are stuck with.
But from my experience I would say equal loudness curves, along with compression and distortion in the middle ear. It's well documented that pitch (and I think rhythm) get herder to discern at high SPL. Perhaps our abilities to hear room problems get swamped at high SPL.
As I said, it's not pretty but it works. Sometimes it's better than the awful acoustics we are stuck with.
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