T60 Limit

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SethRocksYou
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Re: T60 Limit

#61 Post by SethRocksYou » Wed Aug 29, 2018 12:46 pm

Ryan A wrote:
Tue Aug 28, 2018 5:05 pm
Not making any assumptions. I hear what I hear. You couldn't convince me the dog I'm looking at is a cat just because you're a veterinarian. Cheers.
Given who the "veterinarian" is in this case, I'm personally keeping my mind open to an alternate reality in the matter. And, I too am coming from "I hear what I hear".

Like Brent mentioned, there is much that I'm taking for granted. One of them is actually a blaring question. When I put a sine wave on, on my computer, what is actually being produced in my ear canal? Is it only 25hz? If not, what other frequencies and at what intensity might they be compared to the intended sine wave that I'm so sure I'm hearing?

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Re: T60 Limit

#62 Post by SethRocksYou » Wed Aug 29, 2018 1:59 pm

Great post Brent :thumbsup:


BrentEvans wrote:
Wed Aug 29, 2018 10:21 am
Have you ever had your assertions tested in a double-blind scenario, as was mentioned earlier? Using the testing method you described, where you are in control of the test parameters, you are subject to confirmation bias. It would also be interesting to see an analysis of the actual frequency content you are hearing. There is a difference between natural harmonics, which ALL electromechanical reproductions have, and layering in generated harmonics. The effect would be completely different.
It's unlikely that any of us here will ever be part of a true double-blind test of any sort. Where neither the test administrators nor the testees (no, not those ones :mrgreen: ) have any idea what the test is about. Let alone having the results be "Peer Reviewed" (I know, not mentioned)

I haven't been able to find a single piece of evidence, anywhere on the internet, that counters the 20-20,000hz that's widely accepted... Except the mention by some sources that it actually extends down further, to 16hz. This thread is the first and only I've ever heard of someone claiming the lower limit of the hearing range doesn't extend to down to 20hz.

I too think it will be interesting to see an analysis of the actual frequency content I'm hearing. Which currently I believe "is what it is". I won't be able to test it for a week or so, but I'm very anxious to see the results.



Further, if you are listening in earbuds or headphones, you are experiencing a different pressurization method than real world sound.

I'm not sure it's really fair to add or take away a value like "real world", as if to say one is better, worse, or more or less valid than the other. Perhaps a different pressurization than half, quarter, or eighth space. Even being different, if you can hear something when using one configuration that you can't hear in another configuration, the remaining conclusion is just that. Isn't it?



With both ears receiving an identical signal but being pressurized from different directions, you are certainly more apt to perceive that signal from the sheer air pressure. Experiencing that effect is not the same as hearing the frequency. If you were to produce a similar SPL at your ear from a distant point source somehow devoid of all natural harmonics and reflections, your ears would experience the sound pressure, but not the air pressure. You would perceive that very differently, and perhaps not at all, depending on the circumstances.
I completely see this point. It pretty much encompasses the spirit of what I find so intriguing about the conversation. I'll share my experience. Or maybe more accurately, how I experience my experience.

Totally unscientific at this point. There's so much room for argument and critique in this and I completely know it. But, here it is. Playing (supposed) sine waves on YouTube, through my computer and $20 earbuds, the difference between 50hz and 25hz is night and day and every step down from 50 and beyond 25 is noticeably different and lower. Others have said it too and you make the good point again, about air pressurization. Because, I get the sensation of air pressurization in my ears even down at 10hz. It's a very good point, because my mind thinks I'm hearing something. But, if I'm very honest with myself, it doesn't register as a tone. As I mentioned earlier, 16hz plays games with my mind. I feel the pulsing pressure, but the prescience of a tone forms then goes away, then forms and goes away. It's a weird sensation. Kind of like losing balance and regaining it. There's certainty, then uncertainty.

That's what my personal experience is. And, how I experience my experience. Yes, completely subject to confirmation bias. And completely unconfirmed frequency content.

I suspect viewing the results on a spectrum analyzer will answer a lot of questions. I'm completely open to being wrong here. My gut's still stubbornly adamant though.



To not be willing to test your knowledge, thereby admitting the possibility that you might be wrong, is basically the same as egotism.
I couldn't agree more. For everyone involved, from every perspective. Let's keep our minds and dialogue open.

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Re: T60 Limit

#63 Post by Grant Bunter » Wed Aug 29, 2018 5:45 pm

Reasonable dialogue yes, meaningful dialogue though is arguable IMHO.

How many of us are listening to music or sounds like pipe organ (down to 20Hz), bassoon (down to about 30 Hz), or harp (35Hz) on a regular basis, and requiring audio systems capable of reproducing those, or trying to reproduce those instruments through PA?
The issue with the lowest frequencies is having the capability to reproduce them.
Even if you have a cab and speaker combination that can do so, you then also need to find amplifiers that can also adequately cover those frequencies without running said amplifier harshly at it's operational limits in terms of frequency, so that below 20Hz content can be reproduced at significant audio levels.
The greatest majority of amplifiers are rated 20Hz-20K, because that is the convention about the capability of human hearing.

I get that you might want to be able to reproduce infrasound for HT (thunder, dinosaur stomps etc), but does being able to hear an extra 5Hz below 20Hz add to the experience? If so, how?
If one uses thunder as an example, it's great to hear more realistic reproduction of thunder in say a movie, but in reality, it's an attempt to evoke a memory, because we all know that what you hear in the movie is nowhere near the same as experiencing real thunder, because you can't reproduce the intensity of real thunder, due to physical constraints.

As far as I can see, infrasound frequencies (ie below 20Hz) don't exist in any conventional musical instruments made by man.
Or, if any of those instruments actually do have response below 20Hz, it has neither been mentioned or measured.

So what is the point of working out if one can hear 15Hz or no?
Is 15Hz a frequency we want to adequately reinforce in sound reproduction?
Is 15Hz a frequency we regularly want to introduce into music?

As a generalisation, some genres of modern music seems to be concerning itself with lower and lower content, but to what purpose?
If there is 15Hz content in a given song/track, then it has not been put there by conventional musical instruments in terms of evidence/research to date.
Recording some generated waveform has to be the source.

When it comes to heaphones/buds, how do we know we are hearing a fundamental 15Hz and not the harmonics, or some of the harmonics?
Even calibrated headphones in a controlled laboratory environment will still generate harmonics, because it's the nature of loudspeakers/transducers to do so...
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Re: T60 Limit

#64 Post by SethRocksYou » Wed Aug 29, 2018 6:32 pm

Those are all good points too Grant. Totally valid.

Never mind the bottom of the hearing threshold, I'm intrigued by Bills claim that we can't hear 25hz. When, to me, it "seems" plain as day that I can.

I didn't get that there was any debate about the usefulness (or lack thereof) of being able to reproduce ultra low content. Was there? I must have missed it.

Interesting tidbit about pipe organs... there are 2 in the world with 64 foot stops, resulting in an 8hz fundamental. One with a 128 foot stop... you guessed it... 4 hz fundamental. How crazy is that!?

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Re: T60 Limit

#65 Post by SethRocksYou » Wed Aug 29, 2018 6:42 pm

Did a quick search to double check my "facts"... the 128 foot stop might not be exactly as I recall... just a disclaimer. Don't quote that to your friends without verification. I really should have verified it first too.

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Re: T60 Limit

#66 Post by Grant Bunter » Wed Aug 29, 2018 6:54 pm

SethRocksYou wrote:
Wed Aug 29, 2018 6:32 pm
Never mind the bottom of the hearing threshold, I'm intrigued by Bills claim that we can't hear 25hz. When, to me, it "seems" plain as day that I can.

I didn't get that there was any debate about the usefulness (or lack thereof) of being able to reproduce ultra low content. Was there? I must have missed it.
Well, we either hear or feel 25Hz is what science says, depending on what you read.

When you started the thread it was about drivers/voltage, moved to fundamentals (or lack thereof) and hearing.
I just put some observations in about the relevance of that, in regards to reproducing sound.
Another tangent perhaps?????
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Re: T60 Limit

#67 Post by Bill Fitzmaurice » Wed Aug 29, 2018 7:07 pm

The pipe fundamental is only a small part of what you hear. This charts the spectral content of an 8 foot pipe:

Image

The 1st harmonic is the fundamental. You can see that the 2nd and 3rd harmonics dominate, while even the 5th and 7th harmonics are louder than the fundamental. The dominance of the harmonics versus the fundamental increases as the pipe frequency decreases. The realization of what we actually hear with bass instruments is what led to the missing fundamental.

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Re: T60 Limit

#68 Post by SethRocksYou » Wed Aug 29, 2018 7:09 pm

Grant Bunter wrote:
Wed Aug 29, 2018 6:54 pm
Well, we either hear or feel 25Hz is what science says, depending on what you read.

When you started the thread it was about drivers/voltage, moved to fundamentals (or lack thereof) and hearing.
I just put some observations in about the relevance of that, in regards to reproducing sound.
Another tangent perhaps?????
Oh yeah, there's easily 3 or more subjects being discussed.

I'm in agreement with much of the points you presented.
Last edited by SethRocksYou on Wed Aug 29, 2018 7:38 pm, edited 1 time in total.

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Re: T60 Limit

#69 Post by SethRocksYou » Wed Aug 29, 2018 7:37 pm

Bill Fitzmaurice wrote:
Wed Aug 29, 2018 7:07 pm
The pipe fundamental is only a small part of what you hear. This charts the spectral content of an 8 foot pipe:

Image

The 1st harmonic is the fundamental. You can see that the 2nd and 3rd harmonics dominate, while even the 5th and 7th harmonics are louder than the fundamental. The dominance of the harmonics versus the fundamental increases as the pipe frequency decreases. The realization of what we actually hear with bass instruments is what led to the missing fundamental.
What comes up for me as a question (although posed as a statement LOL) is... the harmonics that a musical instrument produce, which result in each instrument sounding distinctly unique seem to be fairly faithfully reproducible on most sound systems without grossly coloring the original sound, even with missing fundamentals. Any harmonics that are added by the signal processing, amplification, and reproducing speaker are at such a low level that it's not perceivable to most. A trumpet sounds like a trumpet. I just have a hard time wrapping my head around the idea that a pure sine wave, void of any harmonics, would incur so much distortion in it's reproduction that the added distortion occurs as a sine wave/single frequency and is the only notable sound. I can conceive it and picture it in my mind. I get the idea. But, I'll have to see it on a spectrum analyzer before my ego allows it past the guardian gates and into my reality.

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Re: T60 Limit

#70 Post by Rich4349 » Wed Aug 29, 2018 7:37 pm

Bill Fitzmaurice wrote:
Wed Aug 29, 2018 7:07 pm
The pipe fundamental is only a small part of what you hear. This charts the spectral content of an 8 foot pipe:

Image

The 1st harmonic is the fundamental. You can see that the 2nd and 3rd harmonics dominate, while even the 5th and 7th harmonics are louder than the fundamental. The dominance of the harmonics versus the fundamental increases as the pipe frequency decreases. The realization of what we actually hear with bass instruments is what led to the missing fundamental.
Taking that into consideration, it almost gives rise to the argument of "what if you just REMOVED the fundamental, since the harmonics are so much louder? Would you still hear a tone that isn't there, since so much of what we perceive as, say 25 hz, is in reality 50+75+100...?" Like seeing a shape just by its outline?
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Re: T60 Limit

#71 Post by SethRocksYou » Wed Aug 29, 2018 7:40 pm

Rich4349 wrote:
Wed Aug 29, 2018 7:37 pm
Taking that into consideration, it almost gives rise to the argument of "what if you just REMOVED the fundamental, since the harmonics are so much louder? Would you still hear a tone that isn't there, since so much of what we perceive as, say 25 hz, is in reality 50+75+100...?" Like seeing a shape just by its outline?
Now you're catching on :thumbsup:

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Re: T60 Limit

#72 Post by Rich4349 » Wed Aug 29, 2018 7:41 pm

And what about the fact that folded horns remove said harmonics? Or is it moreso they reduce them to imperceptible levels?
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Re: T60 Limit

#73 Post by SethRocksYou » Wed Aug 29, 2018 7:53 pm

Harmonics and harmonic distortion are two different things.

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Re: T60 Limit

#74 Post by SethRocksYou » Wed Aug 29, 2018 8:41 pm

Rich4349 wrote:
Wed Aug 29, 2018 7:41 pm
And what about the fact that folded horns remove said harmonics? Or is it moreso they reduce them to imperceptible levels?
On second thought, that's not a bad question. If harmonic distortion is typically harmonics added to the source signal, how would they not just pass through as if they were harmonics present IN the original source material. I don't know. Might have to take another look at that Klipsch Paper.

In the mean time... http://audiojudgement.com/total-harmoni ... orial-thd/

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Re: T60 Limit

#75 Post by Bill Fitzmaurice » Wed Aug 29, 2018 8:46 pm

Harmonics and harmonic distortion aren't the same thing, but they're closely related. Harmonic distortion is when the harmonic content present in what's heard is different than that in the original signal. Usually that means there's more harmonic content, but in rare instances there can be less.

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