[Ultralight]

Question of the day/week.

Why do most tweeters now go way beyond 20 khz which is supposed to be the hearing limit of most mortals?  Mine is be low that.

Surely it can't just be for bragging rights as lots of $ goes into the design.  Yes I realize that the impulse to brag is part of human nature but surely there are better reasons?   Do we have sensory perception beyond what science may be documenting? Or....?

Thanks.
UL

[FullRangeMan]

The human ear can hear the harmonics from a hi freq sound even if fundamental note or tone is beyond 20Khz.
The ear will feel it as a relaxed, extended and natural tweeter as is know in the ribbon tweeters.

[srb]

The human ear can hear the harmonics from a hi freq sound even if fundamental note or tone is beyond 20Khz.
The ear will feel it as a relaxed, extended and natural tweeter as is know in the ribbon tweeters.

It's a shame you won't get that from a full-range driver.

[FullRangeMan]

It's a shame you won't get that from a full-range driver.

Some day they will do it.
Now we are close to it, the Carver Amazing 60'' ribbon range to 200Hz to 40kHz.
It only dont have hi sensitivity, just 89dB spl what require a muscular amp.

[Early B.]

OP -- think of the high end of the spectrum in the same way as the low end where we can't hear below 20Hz, but we can feel it.

[Pete Schumacher]

Extending the frequency response beyond hearing limits has an immediate benefit in the phase domain . . . less phase shift in the passband below 20Khz.  Whether or not that is audible is debatable.

But since it's no big deal to get a tweeter to surpass 20KHz, why not?

[JonnyFive]

Can anyone point to any good articles on the subject?

Wouldn't this be like saying: "My TV outputs X-rays, and even though I can't see them, it makes the picture look better" ?

[simoon]

It makes sense from an engineering standpoint.

A device, whether it is a tweeter, transistor or even a car engine will perform better within it's optimum range if it is designed to perform beyond it.

Why do most cars have engines capable of going over 100 MPH, if they hardly ever go over 70?

[Wayner]

Everything has a beginning and an end. The beginning is full of anticipation, the end is full of desperation.

[srb]

Everything has a beginning and an end. The beginning is full of anticipation, the end is full of desperation.

?

Was this intended to be a reply to the topic System Upgrades - Does it ever get done? ?

Steve

[S Clark]

If you can't hear it, feel it, taste it, see it, or pick it up with esp, I have my doubts that it is more than specs for advertising. 

[Wayner]

?

Was this intended to be a reply to the topic System Upgrades - Does it ever get done? ?

Steve

No. I thought it was appropriate for a follow up to the 100mph car analogy. You know, volume controls go from about 8 o'clock to 10 o'clock in most systems, why a full blast setting?

Speakers that go to 40k? Maybe your dog can enjoy it. Why not speakers that go to 100k or 200K. (oh, that might be the price too). If you understand how my comment fits into to all of this, then you think like I do, If not, well then you don't.

[kernelbob]

If you high frequencies are -3 db at 40k, you're getting phase rotation at 20k.  As far as not being able to hear above 20k, most of us can't hear much past 10k if we're lucky.  However, "hearing" is usually taken to mean being to recognize a pure tone at a given frequency.  Even if you don't hear a pure tone much past 10k (or less), you will hear a loss of qualities usually described as openness, air, fine detail, transparency, etc. when the high frequencies are compromised.  Those compromises may not just be in how high or how low a driver goes, but with time dispersion or smearing.

On the other end of the spectrum, slow bass (i.e. slow woofers, muddy crossovers, etc) will prevent the midrange from sounding fast far above the limit of the woofers or subwoofers.

The problem with reliance on numbers is that there are other types of quality not contained in the "20 to 20k" response range or the percent distortion (harmonic, IM, TIM, whatever).  My two cents worth anyway.

[Don_S]

In the good old days (where some of us still live) was it easy to get a speaker to exceed 20KHz? I am wondering if the 20KHz isn't a throwback standard to days when that was quite an achievement and 20Hz-20KHz was what everyone expected. 

Also remember 20KHz isn't where a tweeter stops.  It is just the measurement many designers try for within the +/- 3dB window.

[dlaloum]

Most tweeters start throwing out a range of nasties (less if it is a soft dome, more if it a hard dome design, ribbons and other exotic types have their own "signature" nasties ) when they approach their limits...

If you put the limits further out, then you move the nasties further away as well.... or at least, by feeding a 40kHz capable tweeter a 20kHz diet, you keep in it is easy peasy cruisin performance zone...

Additionally there are phase effects as a driver hits its non linear frequencies (ie where it starts rolling off) - and moving the rolloff F further up, also moves the phase issues up and away into less harmful (and possibly inaudible ultrasonic) areas.

40KHz is nice - but still a bit close to 20kHz when this is all considered - it is only a single octave above 20kHz.... really what we should be looking for to really move the nasties out to where they do no harm is more like 2 octaves or 80kHz. (which is roughly analogous to the difference between 96kHz PCM and 192kHz PCM, where the limit frequencies are 48kHz and 96kHz respectively...and for some of the very same reasons - although in this case filter related)

bye for now
David

[SoCalWJS]

I don't know why it makes a difference, but it does. I think the explanations above make sense in that we can perceive some sounds above 20k in so much as that if the frequency cuts out at around 20k, things just don't sound quite right. Ambiance. Decay. Whatever.

I actually sat through multiple demos of a "add-on" Supertweeter at one of the big audio shows a couple of years ago. They claim that all they do is turn the Supertweeter on and off - same piece of music, same equipment, same volume, etc. (I certainly did not see them make any other changes). They said it extended out to the neighborhood of 100k.

Difference was not subtle. Neither was the price. 

...but it was impressive.

[Ultralight]

Thanks everyone.  Very helpful.  Many of the responses makes sense.

So how much does the 100K tweeters cost?   (Kidding....if I have to ask, I can't afford it.   )

UL

[SoCalWJS]

Thanks everyone.  Very helpful.  Many of the responses makes sense.

So how much does the 100K tweeters cost?   (Kidding....if I have to ask, I can't afford it.   )

UL

The ones I listened to were the Enigma acoustics. About $3700/pair

http://www.stereophile.com/content/enigmacoustics-sopranino-electrostatic-supertweeter

*EDIT* - although their spec sheet says 40k. Could have sworn they said 100k at the show 

[FullRangeMan]

Thanks everyone.  Very helpful.  Many of the responses makes sense.

So how much does the 100K tweeters cost?   (Kidding....if I have to ask, I can't afford it.   )

UL

Look for plasma tweeter if you want the most hi freq response in treble.

[dlaloum]

The Gallo CDT tweeters get up around 35k which is not too shabby