Shouldn't we upgrade the 20-20 audible range ?!

[SIY]

DAMPENING FACTOR

Damping. Dampening means to make something moist. /pedant

It's actually a pretty useless spec, especially because of the ambiguity as to the reference impedance and that it's taken at a singe frequency (usually 1kHz). Source impedance across the audio band or at least at spot frequencies is far more useful.

 

[danadam]

And a more generic question for the 'opposition' in this thread. Your 'sneezing' at everything new was and is very audible. You already made it clear that you are against any possible form of progress or change (in terms of FR/20-20). Fine with me, anyone has the right to be as negative and anti as they wish. And good luck with that!
But just curious: is there anything you are actually FOR?

Already answered:

It's borderline amusing how obsessed you are with this puny molehill of an issue, when the veritable mountain is right there in front of you and all of us who love home audio: the patent non-transparency of loudspeakers *within the 20Hz-20kHz band* combined with commonly-not-great room acoustics *within the 20Hz-20kHz band*. And that's just on our side. On the production side it's the frickin' wild west, always has been, so the circle of confusion spins on and on and on....

 

[solderdude]

There is only a group of researchers/experts who managed to DYI their way into beyond-20-20. And they came back saying "go for it, it is wonderful"...

Nonsense.... audio can be well below 20Hz (usually electronic music) and also above 20kHz.
The limits you speak of do not exist (only the 20kHz limit of CD is an actual sharp limit)

 

[solderdude]

Do many acoustic instruments produce sound above 20 KHz? Flute or Piccolo? Cymbals or Bells?

Frequency response of a Zildjian 20-inch ReZo crash cymbal. Notice the energy density between 100 Hz and 10 kHz. The magenta spectral line is the peak volume at the initial crash. The yellow trace is the sound level two seconds afterward, so the yellow line shows the decay.

As can be seen the most 'energy' in a cymbal crash (purple line) is in the 3kHz-10kHz range. 20kHz is already 40dB below the 3-6kHz range... and 70dB SPL while the crash itself is a whopping 110dB SPL over a wide bandwidth. Really only experienced by a drummer not wearing IEMS or hearing protection.

Where Lashto thinks the 'magic' might be is not where he thinks it might be.

 

[Killingbeans]

I did not follow the "we can't hear it" parallel discussion.
This thread is about what we can hear: i.e. at the very least 8-28. And the very real/measurable/proven effects of 'inaudible'.

Again; Hearing a single test tone cranked up 100dB is not the same as hearing the faintest harmonics of a bunch of instruments in a piece of music.

You'd might "hear" it for a split second, right before you go deaf, if you put your head inside the horn of a huge PA speaker at max volume.

But detecting anything even close to 28kHz when simply listening to music on a normal "ultrasonic" playback setup? Forget about it...

May I ask what exactly is the "can't hear it problem" and what makes it ontopic ?

It's on topic, because there's no point in talking about including something into a standard, if it has zero relevance for the system being standardized.

It's like demaning that water should always be labeled as "poison", just because it can kill you if you drink extreme amounts.

 

[MAB]

And a more generic question for the 'opposition' in this thread. Your 'sneezing' at everything new was and is very audible.

Super tweeters are old, nothing new. And are they very audible? Have you ever owned or listened to a super-tweeter? You dramatically exaggerate, which doesn't help your argument.

In any case, thanks for blast from the past. I'm looking through old catalogs and speaker magazines now. For instance Radio Shack:

Fond memories, my friend had these. Another friend's dad had a really fancy pair of super tweeters stacked on top of his speakers. Back then, I had a pair of Pioneer speakers with super tweeters too. I don't anymore. Not because I got old, rather I decided when I was in high school there were better problems to solve in the manifestly audible range, and wanted good speakers, rather coveting something to satisfy my OCD. And many of the solutions to your 20-20 upgrade problem seemed to cost as much as a pair of entire speakers, some things don't change.

If you want to 'upgrade your 20-20', why don't you just buy a pair of those Pioneer super tweeters used in the study? People selling your dream, just go and buy-it-now. You could report back to us how much they upgrade your system, or not. Your Gish gallop style with studies of people getting scalp-itch when subjected to >20kHz pure tones above 100dB aren't going to win over anybody here who has one iota of common sense. And you don't seem to appreciate or be able answer questions about some of the assumptions and extrapolations you are making. Put your money where your mouth is, buy some fancy tweeters and get back to us with some relevant observations. While you're at it, why don't you use the front-end of an oscilloscope as a preamp? Where is the community of DIY enthusiasts hacking marine radar amplifiers to get better sound? Why are the OpAmp-rolling crowd not inserting wideband OpAmps into their gear... Oh wait, they are doing that, and their gear is exhibiting high-frequency oscillations and distortion, yet they are ranting about 'very audible' improvements. There are other forums where your quasi-science 'upgrade the 20-20' idea, combined with disposable income, would generate interest. I recommend GoodSoundClub.

 

[Davide]

IT's still nice to have DAMPENING FACTOR AND SLEW rate, a lot can be inferred from those 2.
And different years of the same make/model amp cam have enough differences particularly in DAMPEMING FACTOR) that can make a difference in whether or not you are going to use it as a subwoofer amp for your custom made subs). I believe that SLEW RATE is also a factor in the low end and how well the DAMPANING FACTOR works in controlling the starting & stopping part of the sub-woofers movement.
Lashto, while he is concerned about the deep low end, seems even more concerned about the high end (where both the SLEW RATE AND TRANSIEN RESPONSE are IMHO more important than the DAMPENING FACTOR).
I could be wrong, I have been wrong before. If you don't believe me, just ask my wife.

Can you explain better what you mean? I don't understand.
Slew rate is another way of expressing bandwidth. And for sure that of the physical driver is lower than that of the amplifier, which is lower than that of the DAC, usually. So what's the point in measuring it if an amp has min 20khz bandwidth?
As for the damping factor, I believe that the choice of the term is unhappy as with the ground pin of balanced connections.
It doesn't mean actually how able is the amp in stopping the cone.
Some words from Bruno P. that I liked:
Bruno: It’s quite possible that shop owners would have less fun if all amps had sensibly low output impedance. But beyond “sensible”, damping factor is completely overrated in my view. Once output impedance is low enough to keep response changes due to load variations to within a small fraction of a dB it’s low enough. The term damping factor is seriously misleading because some folks think that an amp with a DF of 1000 is ten times better at stopping a moving cone than one with a DF of 100. It doesn’t make a jot of difference. In both cases the resistance of the voice coil, the crossover filter and even the speaker cable will dominate totally.

 

[SIY]

Slew rate is another way of expressing bandwidth.

That's a common error. It's not. Slew rate is often confused with rise time, which DOES directly relate to bandwidth. They have some relation, but two systems with the same bandwidth can have very different slew rates.

 

[Davide]

That's a common error. It's not. Slew rate is often confused with rise time, which DOES directly relate to bandwidth. They have some relation, but two systems with the same bandwidth can have very different slew rates.

Yes, I agree, technically speaking.
In practice with Slew Rate = 2 x π x Frequency(max) x Peak Voltage, since Peak Voltage is a constant, F(max) (calculated with 10-90% delta voltage) correlates reasonably well with the amp bandwidth, although not the same thing as per its standard -3dB definition, of course (there is a very practical explanation on AP website).
But still an indication of maximum frequency that is correctly amplified.
This was to say that measuring the slew rate in finished amps is generally useless for audio performance purposes (for us), and people shouldn't worry about transients in audible band.
Maybe testing with a particular type of load, as @pma does, can reveal something new, but I'm not sure it's something audible in the end.

 

[SIY]

This was to say that measuring the slew rate in finished amps is generally useless for audio performance purposes (for us), and people shouldn't worry about transients in audible band.

100% agree. Re: the latter, by definition, the transients are limited in dV/dt by the bandwidth.

 

[PGansz]

I do too, but I see no reason to exceed FR requirements by a huge margin when it brings no benefit. Good engineering isn’t about exceeding all possible specs, it’s about prioritizing specs and ensuring they are met at an acceptable cost.

Pushing the envelope to go beyond what’s necessary is admirable when it solves some problems that were previously unsolved or were hard to solve. Building circuits that handle 100kHz, MHz, or even GHz range is done routinely, this isn’t new. So what is the purpose of over-designing audio circuits where there is no actual benefit to the extra effort and cost?

You exaggerate to make a point and I understand why...I never said by a huge margin or in a specific area. I am again, simply stating the facts about moving design goal posts to a broader range will bring down costs and result in better products.

One might ask, how do you know? Well, uh, look at the measurements Amir does. Very few flat lines from 20-20 as far as I can tell.

Everyone keeps bringing up ultrasonics...that was never mentioned by me. I can't even hear past 15.5k. But I know it will result in cleaner measurements through 15.5k if someone designed a flat target from 3-30, simply because the sweet spot will get larger.

He'll, let's just see a flat line on any speaker from 20-20...I won't hold my breath.

Again, lots of big brains here arguing against things I never stated, and incredibly obvious benefits to the philosophy.

 

[PGansz]

I want immovable goal posts if they are already in the perfect position to accomplish the desired goal.

Moving them around just because it is technically possible is not beneficial to the end user of the goal posts, only to the person who is being paid to move them.

They're not. Plenty of people enjoy bass below 20hz. That's easy pickins.

It's really interesting to see someone arguing about science and its methods and benefits, while using terms like "perfect".

That's just odd at best.

 

[EJ3]

Can you explain better what you mean? I don't understand.
Slew rate is another way of expressing bandwidth. And for sure that of the physical driver is lower than that of the amplifier, which is lower than that of the DAC, usually. So what's the point in measuring it if an amp has min 20khz bandwidth?
As for the damping factor, I believe that the choice of the term is unhappy as with the ground pin of balanced connections.
It doesn't mean actually how able is the amp in stopping the cone.
Some words from Bruno P. that I liked:
Bruno: It’s quite possible that shop owners would have less fun if all amps had sensibly low output impedance. But beyond “sensible”, damping factor is completely overrated in my view. Once output impedance is low enough to keep response changes due to load variations to within a small fraction of a dB it’s low enough. The term damping factor is seriously misleading because some folks think that an amp with a DF of 1000 is ten times better at stopping a moving cone than one with a DF of 100. It doesn’t make a jot of difference. In both cases the resistance of the voice coil, the crossover filter and even the speaker cable will dominate totally.

I will go after your first question first (please feel free to research this, particularly from other sources [but this source actually does a fairly good job of explanations of these problems]):

Slew rate:​

From Wikipedia, the free encyclopedia

The slew rate of an electronic circuit is defined as the rate of change of the voltage per unit time. Slew rate is usually expressed in units of V/μs.[4]

SR=max|out()|

where out()

is the output produced by the amplifier as a function of time t.

I do not see how expressing the RATE of CHANGE of the VOLTAGE per UNIT TIME is expressing bandwidth.

Damping factor:​

From Wikipedia, the free encyclopedia

In practice:​

It is clear from the various amplifier frequency response curves that low damping factor values result in significant changes in the frequency response of the amplifier in a number of frequency bands. This will result in broad levels of sound coloration that are highly likely to be audible. In addition, the frequency response changes will depend on the frequency-dependent impedance of whichever loudspeaker happens to be connected to the amplifier. Hence, in high-fidelity sound reproduction systems, amplifiers with moderate to high damping factors are the preferred option if accurate sound reproduction is desired when those amplifiers are connected to typical multi-way loudspeaker impedance loads.​

IMHO it is somewhat overrated when dealing with higher frequencies (say above sub to woofer crossover & certainly below the woofer to mid or tweeter crossover.
Also IMHO dampening factors over 200-250 don't seem to make much difference but one of 25 vs one of 250 does IMHO.

Now, if you use the on board amp active sub-woofers that many do these days, it's probably a moot point.
But I have a preamp with external crossovers running to separate amps for the mains (1 amp each [the lowest OHM of the mains is 4.8, so running as 8 OHM units] {with a touch over 1000 WATTS RMS each}) and the sub-woofers (1 amp each, the OHM rating is 4 OHM, FR is 20 Hz-80 Hz, so running as 4 OHM units {with a touch over 1600 WATTS RMS each}).

 

[pkane]

You exaggerate to make a point and I understand why...I never said by a huge margin or in a specific area. I am again, simply stating the facts about moving design goal posts to a broader range will bring down costs and result in better products.

But that’s the issue: how is a product better if it doesn’t improve at all on its basic function? That was why I mentioned a carburetor on an EV: extra bandwidth beyond the audible range is just as useful.

One might ask, how do you know? Well, uh, look at the measurements Amir does. Very few flat lines from 20-20 as far as I can tell.

Hmm, I actually see a lot of almost completely flat line frequency responses for all non-transducer electronics. This is not hard to do in 2024, and costs little.

Everyone keeps bringing up ultrasonics...that was never mentioned by me. I can't even hear past 15.5k. But I know it will result in cleaner measurements through 15.5k if someone designed a flat target from 3-30, simply because the sweet spot will get larger.

But you still haven’t provided a good reason for this. What will actually improve that needs improving?

He'll, let's just see a flat line on any speaker from 20-20...I won't hold my breath.

how does the non-flat FR of some speakers below 20kHz justify extending their response beyond 20kHz?

Again, lots of big brains here arguing against things I never stated, and incredibly obvious benefits to the philosophy.

That’s the thing: you still have not actually mentioned, much less, provided support for the need for these “obvious benefits.”

 

[kemmler3D]

View attachment 377623


As can be seen the most 'energy' in a cymbal crash (purple line) is in the 3kHz-10kHz range. 20kHz is already 40dB below the 3-6kHz range... and 70dB SPL while the crash itself is a whopping 110dB SPL over a wide bandwidth. Really only experienced by a drummer not wearing IEMS or hearing protection.

Where Lashto thinks the 'magic' might be is not where he thinks it might be.

I think this really illustrates the strength of the case fairly. We have the >20khz components in a plausibly audible state, but not easily - assuming your hearing in that range is basically perfect.

30dB down is a lot quieter than you might think by seeing a line drop 3 ticks on a chart like this, (I just tried playing two songs at once with one at -30dB, I'd describe it as "vague whispers in the background" at best) but it's not outright inaudible.

And this is probably the "worst case scenario" in terms of real musical content we might lose without supertweeters and high-res formats. Is this worth buying a supertweeter for you? Go for it.

Personally:

• I can't hear that high up anyway
• I don't think a lot of music I listen to is mixed and encoded for >20khz content anyway
• I don't have any FOMO about ultrasonic content in the first place, I cured myself of that years ago.
• Even if I bought a supertweeter setup and only listened to music with ultrasonics and my hearing was perfect, the difference would be slight and the hassle considerable.

And I think the argument for advancing the state of the art by raising the bar gets it backwards. Convincing people they need ultrasonic equipment would just steal resources from the still-in-need-of-improvement normal woofers and tweeters. Consumers' budgets will not expand to accommodate supertweeters, brands will just have to cut corners somewhere else to fit them into the BOM and hit the same price targets as before.

Ultra-high-end subjectivist types already buy this stuff if they have a mind to.

 

[solderdude]

I believe that Lashto has convinced himself that:

• people can actually hear (but not through the ear-canal/ear-drum) well above 25kHz, even when the sounds are faint. He bases this on the works he quoted.
• people can actually hear well below 20Hz (also not at high SPL) and use other 'senses' than the auditory channel.
  There is actually some truth in that as the body can feel LF extension which adds to the experience. Unfortunately for speakers in a room this is not really possible. For ear/headphones is possible to go down to 5Hz for instance... but one will be missing the tactile feel.
• Another of his misconceptions is that recordings are all truncated sharply below 20Hz and above 20kHz and that transducers and amps do the same. The fact that most measurements only show 20-20k reinforces his belief as well as the mentioning of 'reaching 20-20k' in the folders and leaflets.
• Then he rants about microphones not reaching those limits and for some (usually specialized) mics that is true as they are shaped in FR and not flat for a reason. There are plenty of mics that far exceed the 20-20k.
• He also seems to believe speakers cannot extend above 20k based on misinterpreted 'info'.
• On top of that it looks like he believes the 'discrepancy' between live (and I assume not sound reinforced) and reproduced sound comes from some or all of the above arguments.
• he is convinced that he 'hears' with more than just his auditory channel. He is right as one also 'hears' with the eyes and body (LF extension at high SPL) and believes that low level >20kHz somehow enters the brain through bone conduction or another 'sensor' that is not defined.

Believing is a powerful incentive to have something proven and that has to be done independently.
I guess what he really wants is to have:

• DACs measured FR (in one plot) of 44kHz, 96, 192, 384 kHz sweeps (all the way down from 1Hz)
• speaker measurements up to 50kHz (from 10Hz up)
• headphone measurements from 1Hz to 50kHz
• amplifier measurements from DC to 1MHz ... just to be sure

All of this to satisfy his FOMO and 'for the science' part for those that think 20-20k is not enough.

DACs measured this way is pretty easy to do
speaker measurements from 10Hz might be a challenge even for a Klippel in a smallish room and above 20kHz requires expensive (calibrated) mics but possible. Don't know how the Klippel handles this.
Headphone measurements below 20Hz require perfect seal and is otherwise easy to do. Above 10kHz (or 15kHz for 5128) will have accuracy issues on HATS and other fixtures so the value of that remains to be seen. Also larger diameter drivers might show comb filtering even when a large membrane vibrates piston alike (which they won't at high frequencies anyway).
FR from DC to 1MHz is possible to do ... or at least to 100kHz. Certainly interesting for tube amps and today's switching amps.
I have seen many amp measurements (by Amir and others) to extend well above 20kHz so that is already covered.

In short.... Lahto's wishlist for making measurements below 20Hz and above 20kHz seems a good idea just because they are basic measurements and some of them are actually possible but rarely seen.

This thread will be an endless argument going back and forth about 'auditory channel', measurements and belief based on some 'research' that shows (or thinks he shows) is evidence.

I'm sure ABX tests will convince him he can't hear it if you truncate below 20Hz and above 20kHz but that may be because he has not seen independent measurements of gear he uses that shows it will reach 5Hz to 100kHz as that's where it matters (I assume using speakers).

 

[Davide]

I do not see how expressing the RATE of CHANGE of the VOLTAGE per UNIT TIME is expressing bandwidth.

Have you read here?

As for the Damping Factor, I don't follow you.
If the output impedance is low enough to minimize the frequency response variations in audio band (usually declared or measured here in the reviews) the Damping Factor says nothing.

As a side note, Bruno P. also said:
In actual fact you wouldn’t even want to have infinite damping because the speaker designer counts on the natural resonance to define the bass response. So it’s rather a good thing that the speaker has its built-in resistance in series with the amp.

The point is that you were saying it would be nice to know Slew Rate, Damping Factor and Transient Response of an amplifier.
But those parameters say nothing more than what is normally declared from manufacturer or measured here/elsewhere.
And anyway you don't need them to compare amplifiers, Distortion/noise measures are more informative.

But this is a bit OT maybe...

 

[Brian Hall]

They're not. Plenty of people enjoy bass below 20hz. That's easy pickins.

It's really interesting to see someone arguing about science and its methods and benefits, while using terms like "perfect".

That's just odd at best.

How do people enjoy bass below 20hz? It can't be heard. Just like we can't hear ultrasonics.

I say reproducing the audible range is what matters. I consider the capability to do that to be perfect.

Needlessly reproducing sounds outside our audible range is pointless and wasteful. I do not understand why anyone would think it was important or a worthwhile goal.

I purchase and use my audio equipment to listen to music that I can hear and enjoy. I am not missing anything by leaving out very low frequency rumbles or ultrasonic screeching. Those frequencies are nothing more than garbage noise to be filtered out.

 

[SorenTyson]

I'd rather go the other way with speakers:

1. If you are serious about bass you should have 2+ subwoofers already
2. If you care about hifi you are anyway so old that you cannot hear above 15kHz

So let's optimize speakers for 80Hz to 15kHz

That should bring prices down, not bigger woofers and additional drivers to reach beyond 20-20.

 

[sigbergaudio]

There is only a group of researchers/experts who managed to DYI their way into beyond-20-20. And they came back saying "go for it, it is wonderful"...

Reference please.