Super Tweeters? Sensible, or a way to annoy dogs and cats?

[John...]

The idea of super tweeters (namely well above ultrasound tweeters) has my blood boiling. Ok, not really. But it seems they are either utterly worthless or at the very least rarely implemented with noticeable audible benefits because how the heck would most people even be able to tell what is correct or beneficial without an EQ or active crossover that can cut the above 20khz frequencies to compare and contrast. Testing equipment is fairly useless. It will no doubt register (hear) the high frequencies, but you won't. The only rationale of super tweeters is that the unheard frequencies interact with the audible spectrum and enrich and improve the experience. But, how much would one have to flood the air waves with above 20khz material? If it's a lot, then yes, super tweeters are simply animal torture devices. And that's not accurate music reproduction. That's simply flooding the airwaves to detect a difference in sound. And then there is the source material. I'm guessing TV, Pandora, most youtube content, most movies, perhaps even most Blu-rays, don't bother with content above 20khz. So where does that leave super tweeter benefits? Limited to SACD and high quality streams I guess. I wouldn't doubt there are SACD's with near zero content above 20khz.

Until super tweeters are tested among controlled double blind tests, they seem largely like a gimmick. And why would I produce tones that only my dog (or cats if I had them indoors) could only hear. It seems cruel if the above 20khz range is overpowered (though it probably isn't). How the heck would I even know if the above 20khz is at a reasonable level? I wouldn't. I'd have to place absolute blind faith in the crossover setup.

One caveat (and a big one). The crossover range is critical. If the super tweeter is crossed at a range between ~8khz to ~15khz, then yes, it can be used to free up and improve the normal tweeter's accuracy. Is this tonal accuracy noticeable. I hope so, but I doubt most would care or notice. Most people just like the bragging rights of a ribbon or super tweeter that goes beyond 35,000khz. Seems kooky.

Does anybody have an active setup or know of any tests that have isolated a super tweeter that crosses over above ~18khz. I'm guessing you can't tell a difference among the audible spectrum unless of course the super tweeter is pushed stupid amounts of power. Congrats, your dog's ears are now bleeding and in no way have you accurately produced the effects of higher harmonics present in a trumpet's sound or any other instrument.

Wouldn't a better solution be to find a tweeter that is good at producing 10khz to 25khz to free up your normal tweeter (provided you can tolerate comb filtering) and forget about this nebulous crack pot science where people brag about frequencies above 25khz?

Animal researches do need ~200khz capability. That's a given. Bottle nose dolphins @ ~150khz. Bats @ ~ 210khz.

Does anybody here purchase speakers based on their super tweeters? When I see a super tweeter, I roll my eyes and think, "It's most likely superfluous and a harmless device to increase sales, but hopefully it integrates well with the overall design and the system still makes great sound." If I see a very high crossover point to a super tweeter I become even more skeptical.

I bet sounds above 20 kHz are vital and integral to how musical instruments vibrate and thus produce sound. Removing these vibrations (which would be impossible) would removes the timbre qualities and a trumpet would no longer be a trumpet, a violin wouldn't be a violin. But once they're recorded the audible harmonic range is probably the only crucial data the listener can reasonably detect. Harmonics both above the fundamental frequency and above the 20kHz point lose their usefulness when reproduced across a speaker.

 

[rojo]

I've got devices that emit around 300 THz in every room of my house. They make a night and day difference.

Re: frequencies above 20kHz, they do nothing for audible sound quality, but you don't need us to tell you this. You can test it if you want, even without super tweeters. Your existing speakers probably play beyond your range of hearing, right?

Install Audacity. Generate a 10kHz tone. Listen to it. Create a second track and generate an overlapping 20kHz tone. Listen to both tracks together. Toggle the solo flag and listen. Have someone else toggle the solo button randomly and don't watch. What do you hear? Can you tell 9 times out of 10 whether the 20kHz track was included in playback?

 

[mtrycrafts]

Welcome.

Actually, experiments have been done, a number of them to see if it matters. So far it doesn't.

As to intermodulation at ultrasonic frequencies is interesting as I am not sure what you are referring to. Withing the tweeter?
In air as after an instrument plays the fundamental not? I don't think that can happen.
And, if by chance the ultrasonic frequency did that, the below 20kHz tones would be recorded as the mic would pick it up as part of the harmonics and if loud enough, we would hear it without that ultrasonic tweeter.
We just don't hear it and has no effect. Probably there is plenty of ultrasonics out there now that we just don't hear it. And, how high might be enough? 50k? 100k? 200?
Just a silly issue looking for a solution.

As to instruments needing to create it, why is that matter if one cannot hear it?
Besides, one cannot filter an acoustic instrument not to reverberate the ultrasonics nor is it created to do so. It is a natural part of a vibrating device to create the fundamental and naturally creates any and all harmonics.

 

[Pogre]

This guy says he got great results using super tweeters...

 

[John...]

Uh, what kind of device do you actually have? They sound kinda scary and/or weird. And mostly useless.

What is the use of 300 thz? It sounds like you're bombarding the air waves as a way to condition the air for your other frequencies? Has it come to this? Are we now conditioning the air. Yikes. If this is for a house is this used to extend the sound waves from a speaker system. Maybe excited air allows a better transfer of sound. Is this what you use the thz frequencies for? I'm intrigued and dumb founded at the same time.

I imagine 300 thz is well outside of dog hearing, but wouldn't 300 thz have to be boosted. Surely this isn't performed at a roll off or even implemented on a flat frequency curve. Are you saying just a little bit of this 300 thz is effective?

What's even crazier and cruel in my estimation is if you're using these devices that dramatically boost frequencies around 40-50 khz. That would drive dogs and cats crazy. I hope you live in a secluded cabin deep in an abandoned mine shaft to spare the animals.

And say what? Run a 10khz tone then a 20khz tone at the same level and then I should be able to tell 9 times out of 10 if the 20khz tone is cut. Call me skeptical, but it should be 100 times out of a 100.

Jeez mate, that's two tones at the same level and one is still supposedly in the audible range (for some youngsters at least). What song if any or what instrument if any is going to produce a 20khz tone at the same level? Are you telling me SACD's are flooding the frequency range to condition the air. Uh yeah, not buying it.

I think you've convinced me. Above 25khz tones are mostly bogus unless you're boosting the living daylights out of the ultrasound frequencies to possibly "condition the air." But that's not accurate sound production. That's air conditioning (not the freeon type).

So, 9 times out of 10 for 10 khz vs 20 khz. So maybe, 6 times out of 10 for for 10khz vs 25 khz.

Cut the 25khz signal in half. And now we're at maybe at 3 out of 10 of detection.

I don't know I'm speculating. But this ultrasound stuff appears to be a never ending clap trap of insanity.

What if the 20khz tone is cut in half (-10db). How many times out of ten can you detect the difference? I'm guessing it would be pathetic.

I'd love to toggle the switch for you and you tell me how many times you heard a difference. Hint: I'd toggle the switch 1 time and wait for an inflated answer from you.

 

[John...]

Well, according to some, you flood the airwaves with 300thz because supposedly 9 times out of 10 you can hear when a 20khz tone is removed from a 10khz. Haha, I'm kidding of course and creating a strawman for a laugh. That's not exactly what he said. He posed the question and hinted that I'd hear it 9 times out of 10, which to me sounds extremely pathetic. It should be 10 out of 10 to justify the benefits of 25+ khz and beyond.

He raises some interesting issues, but it would appear to have any benefit for these ultrasonic frequencies one would have to boost their signal. And that in my estimation is cruel to pets and wildlife and it still doesn't produce accurate music or movie representation.

Possibly flooding the airwaves with thz frequencies can condition the air and lead to further transmission distances of the audible spectrum. Who knows, I certainly don't. Or maybe it creates a fun little artifact that he enjoys, again I don't know.

It just appears that the entire super or ultra tweeter market is a gimmick. Spare no cost systems don't all have them.

One other inquiry? Do large music venues ever use thz frequencies? Maybe that is where the magic of this esoteric science lies. If not, I'm giving super and ultra tweeters a big fat freakin D minus for audiophiles and a F minus for dogs, cats, and other wildlife.

 

[John...]

I don't doubt it LOL!!! Anything would help that system! My side hurts from laughing.

Maybe ultrasonic tweeters are a way to mask any and all sounds emitting form a craptastic setup.

Music sounds horrible?? No problem, put a bird on it...and a super tweeter.

 

[everettT]

Gonna wait and watch this one tonight, nothing on late night tv thats gonna be better.

 

[John...]

Kettle or butter popcorn? Beer or soda?

I'm the first to admit everyone's questions and discussions are a bit stupid and lame, and especially on forums. Each and every answer is probably contained reading textbooks and articles or manuals. But forums can often point one in the right direction faster than any other method. Granted, the wrong answer path comes just as quickly as well.

I'm curious about an issue, but not curious enough to take a college course.

My mostly uninformed take: Ultra sonic frequency reproduction is nearly worthless. The only benefit of using a super tweeter is to lighten up the audible frequency load of the other tweeter. If the super tweeter is able to still produce highs surpassing 20khz and even approaching 30-40khz it simply pads the technical data sheets.

And yeah. It appears he was kidding with his 300thz devices and I took the bait. Who knows. He then went on to describe the "amazing detectability" between an isolated 10khz tone vs a 20khz tone when cut. It's hard to discern sarcasm when one is all over the map.

 

[rojo]

When I say my 300 THz devices make a night and day difference, I mean a literal night and day difference. They're light bulbs. 300 THz is in the visible light range of the electromagnetic spectrum.

The only benefit of a super tweeter is if the loudspeaker as a whole has a deficit at the top of the tweeter's range if the top of that range occurs within audible frequencies. The design of the speaker as a whole determines whether a super tweeter is needed. Most likely, whatever improvement a super tweeter would bring would be more gracefully implemented by a better designed crossover.

 

[John...]

Got it. I re-read and detected your sarcasm a bit too late. Oh boy, ya got me. CLAP CLAP CLAP CLAP

However, you seem to still be in the ultra high frequency defending camp. 9 times out of ten detecting a 20khz tone being cut from a 10khz tone is fairly pathetic. So it would appear ultrasonic frequency reproduction means nothing unless it's just a by-product of a speaker designer trying to lighten the audible frequency load on the main tweeter.

Would any crossover point or use of a super tweeter suggest a bit of marketing tripe to you? If not, ba bye sarcastic South Park dude.

 

[shadyJ]

Ultra high frequency sound pressure waves do not travel far before they lose coherence. I wouldn't worry about the well being of animals hearing unless they are very close to the speakers. Ultra high frequency sound pressure waves would be very directional coming from a speaker as well. They are not likely to have a wide dispersion pattern. Super tweeters have their place, and that is extending the high frequency range of tweeters that can not stretch all the way up to 20 kHz. They can also broaden the dispersion pattern for tweeters that start to beam at frequencies lower than what the designer wants.

 

[John...]

Ok, no problem. I guess I already knew the answers in part but was slightly off track because I started extrapolating the what ifs if somebody was bought and sold by "ultrasound benefits" and then wanted to take their active crossover system and boost a bunch of super tweeters for some odd artifact that he/she liked or thought they heard.

The amount of people that think super tweeters are primarily used to extend beyond 20khz is quite astounding. I know they're used primarily for helping out full range drivers or cleaning up the audible frequency loads on the main tweeters. A lot of people brag all the time about their speaker's frequency range above 20khz.

So yeah, if people are bragging about just how far their speakers extend past 20khz I started worrying that they might be under the impression to use an active system to boost these "unheard benefits" ad infinitum. And then they'd keep boosting away to achieve these "undetectable benefits." Meanwhile their dog is making out with a pistol and trying to pull the trigger.

I guess everything is kept pretty safe with passive crossovers in complete systems. Most people that have any knowledge base aren't rushing out to buy super tweeters to run a massive amount of power through them. But I bet it occurs. There are quite a few dim bulbs doing weddings and dj gigs and also making speakers with ill thought out drivers and crossovers. It wouldn't take much to look at a tech spec sheet and think, "High frequencies above 20khz must be important. They're listed."

The guy's light bulb joke had my wheels spinning even more. I thought, "Oh geez, there might be crack pot products to boost the high frequencies above a dog's hearing along with other wild life. I hope they don't dip too low." Sure you'd skipped right over the last harmonics of trumpets at 100thz and most other instruments containing harmonics between 40 - 90 khz but at least the animals might be spared.

He couldn't have picked a better frequency to confuse me. And for that I give him an A+. It just so happened that it's the visual spectrum of a light bulb. If bats can hear at 200thz then 300thz would be a safe and effective buffer zone for perhaps 99.99% of animals.

I think I'm headed to shark tank with my snake oil device. I'll market a 300 thz device that is safe for animals while also dramatically improving audio quality. It will activate every time a 30-40 hz sound is produced or a 2000-3000hz sound is produced. A little light will blink to show it's working. Base heads will be convinced and electric guitar fans will also swear to its effectiveness.

I'll let this hooch brew a bit more and then I should probably pull the plug on it. I'd actually welcome a moderator to kill it.

 

[John...]

Well, I'm not so sure. Super tweeters would appear to have a benefit if one tweeter or a very small driver produced tonal qualities that sounded quite good from say 3khz to 10khz. The super tweeter would then pick up the frequencies above 10khz.

A tweeter producing frequencies from 2-3khz all the way to 20khz seems like a tall order. I'll admit most systems that do this often sound quite good, so I'm usually fine with it. But maybe there is a benefit in splitting the work that I just haven't fully appreciated. I'm guessing most companies avoid multiple tweeters due to their thoughts on just how evil comb filtering truly is. But is it really? Some companies love comb filtering. Bose (Voldemort), cough cough, made an entire company based around the idea that all sound should sound like surround sound. I think that's a bridge too far but avoiding comb filtering at all costs also seems like a marketing tactic to limit the amount of drivers one implements in their speaker designs.

All right, I'll forgive your 300thz device joke. I just thought you were looking out for nearby bats.

One thing I know about speaker design. There is no holy grail. There are always trade offs. A good designer limits the pit falls inherent in their designs and accentuates the positives through good engineering and quality control. The end result is a speaker that sounds good to the intended audience.

 

[TheWarrior]

Many high quality hard dome (various metals/ceramics) do not enter their first break up mode until above 30khz. But speakers are not specifically 'designed' to roll of at 20 kHz, their frequency response naturally rolls off as a function of propagation loss - tiny wavelengths that lose energy quickly over their distance traveled to the ear.

 

[TheWarrior]

But I should also mention on the subject of 'super tweeters' is that many of them are designed to only perform above +/- 10khz as a purported way to achieve 'crystalline' highs. Not so much that they are intended to reproduce inaudible frequencies, but as a unique design solution in multi way speaker designs.

Or just use a quality tweeter crossed over appropriately....

 

[MrBoat]

Perhaps the frequencies above 25khz is beneficial to keep the metallic parts clean, so that one's super tweeters stay shiny longer. It's not cool if your beryllium doesn't shine.

 

[Pogre]

Got it. I re-read and detected your sarcasm a bit too late. Oh boy, ya got me. CLAP CLAP CLAP CLAP

However, you seem to still be in the ultra high frequency defending camp. 9 times out of ten detecting a 20khz tone being cut from a 10khz tone is fairly pathetic. So it would appear ultrasonic frequency reproduction means nothing unless it's just a by-product of a speaker designer trying to lighten the audible frequency load on the main tweeter.

Would any crossover point or use of a super tweeter suggest a bit of marketing tripe to you? If not, ba bye sarcastic South Park dude.

I'm pretty sure he means you likely won't hear a difference. You'll find most of us in that camp. Audiophoolery usually gets run outta town 'round these here parts.

He got me on the light bulb thing too. I thought Rojo was losing his mind!

 

[AperionAudio]

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[Swerd]

The idea of super tweeters (namely well above ultrasound tweeters) has my blood boiling. Ok, not really. But it seems they are either utterly worthless or at the very least rarely implemented with noticeable audible benefits because how the heck would most people even be able to tell what is correct or beneficial without an EQ or active crossover that can cut the above 20khz frequencies to compare and contrast.

You answered your question early on in your original post, super tweeters are utterly worthless. Let your boiling blood cool off, and ignore those who talk about super tweeters. Whether you're for or against them, it isn't worth getting steamed up about them.

A tweeter's performance at the low end of it's range, roughly 2–8kHz is far more important to what we actually hear. It is worth spending money on improving sound in that range. That does not make sound above that range unimportant, but it isn't worth spending extra money on it.

The only rationale of super tweeters is that the unheard frequencies interact with the audible spectrum and enrich and improve the experience.

That rationale has been invoked before, but only by the irrational.

And then there is the source material. I'm guessing TV, Pandora, most youtube content, most movies, perhaps even most Blu-rays, don't bother with content above 20khz. So where does that leave super tweeter benefits? Limited to SACD and high quality streams I guess. I wouldn't doubt there are SACD's with near zero content above 20khz.

All those are good reasons why we should ignore the effect of sound above 20kHz.

But there is another better reason that is often overlooked. How many recording studios have microphones that respond to sound above 20kHz? Very few.

I've often heard arguments saying that older recordings, made with analog methods before digital sound, were better because they didn't filter out sound above 22kHz. How many of those recordings were made in the 1960s or 70s with microphones that could perform that high? Very few, if any.