The Chosen Tweeter Family

[Steve Gibson]

Gang...

This is a useful and important application note by CTS Ceramics (the piezo folks who purchased the original tweeter injection molds from Motorola) describing the theory of operation of their (and our) piezo tweeters.

http://www.GRC.com/acoustics/CTS_Piezo_Tweeter_AppNote.pdf

/Steve.

[Kindanyume]

Hey all. Just a few of the possible choice I could find for smaller
tweeters that could work

http://nbasmaudio.en.made-in-china.com/product/iqBQEgAGqorM/China-1-Titanium-Dome-Tweeter-W-Aluminum-Housing.html

http://nbasmaudio.en.made-in-china.com/product/KbBmQMAoXqRe/China-1-Titanium-Bullet-Tweeter-100-Watts-Max-ST-005-.html

http://nbasmaudio.en.made-in-china.com/product/EbXJnutysMUV/China-1-Piezo-Tweeters-Flush-Surface-or-Angle-Mount-120-Watts.html

http://nbasmaudio.en.made-in-china.com/product/fboEqmZJaMrc/China-1-75-Tianium-Diaphragm-Bullet-Super-Tweeter.html

http://nbasmaudio.en.made-in-china.com/product/EbOxJdXvrFhY/China-40mm-1-1-2-Dia-Horn-Tweeter-PTW-TS250-.html


some of the smaller ones could easily be flush mounted right into a
small hand held case. :)

Any thoughts etc,,. speak up! (pardon the pun)

[tz]

I got one of the bigger brother KSN-1165 and was curious so I opened it.  There is a thermistor and lightbulb inside.

[tz]

It's protection.  As things get louder the lightbulb stars to glow, if it gets bright the sound cuts off.  So you could measure the power.

[Boilerbots]

When you buy through Alibaba or a site like made-in-china you are putting your money at risk. You typically front the money to an unknown company and then wait an undetermined amount of time for a product to show up that will most like not have a data sheet or meet any specification since there are none.

Some companies are not even manufactures but import/export businesses that simple take your money, translate from english to chinese and then find a manufacture to supply something similar as the photo you see, then export the product to you.

Plus you generally have to order a large quantity.

Or, you could just purchase from Parts Express and let them take the risk, or http://www.madisound.com/ is another I have tried.

[Steve Gibson]

TZ...

I got one of the bigger brother KSN-1165 and was curious so I opened it.  There is a thermistor and lightbulb inside.

<grin>  I've done the same.  If you have those components you have one of the GOOD larger brother tweeters.  Does it have a gold-colored "Powerline" sticker across the back?  How much did you pay for it?  I bought some 470uH inductors which should tune the larger capacitance of the tweeter to around the same 15 khz.

/Steve.

[Kindanyume]

Indeed it can be.. though in my case I have considerable experience at
importing.. so if/when I find working/suitable alternatives believe
me they will be vetted before I would post any actual recommendations.
(including verified samples of designs/products etc as per my usual.
In all the years I've done such I ahve never yet been "victimized"
thankfully. Due diligence is always in order instead of blind
faith.)

Madisound is also a good co to deal with.. I've done so for many many years.

[Kindanyume]

Just a thought Steve,

Would this not be more effective at a 20K+ freq.. beyond typical human
hearing but still within most dogs range? Just narrowing down more
models of piezo etc as most suitable for this purpose. (Also such
would be far less likely to annoy/bother neighbors etc etc Or your
old VP :)

[Steve Gibson]

Kindanyume,

The final question & answer of today's podcast was about EXACTLY that topic.  I assume that you're here because you at least occasionally listen to my Security Now! podcast?  If so, rather than repeating myself (and answer was comprehensive) I'll point you to Q/A #10.  :)

And the graph on this page also shows how rapidly hearing sensitivity begins to fall off with increasing frequency.

http://www.lsu.edu/deafness/HearingRange.html

/Steve.

[Kindanyume]

LOL Indeed.. I've been listening since.. well forever. (I've been
working in IT for decades)

But I nab your 64K MP3's usually on Thurs nights (though they have
been late the last few weeks).. since I can't always just listen w/o
others bothering me etc etc.

Actually we have spoken a cpl times more directly before.. but it's
been sometime to say the least :)

[Boilerbots]

Cool.

[Steve Gibson]

Kindanyume...

LOL  Indeed.. I've been listening since.. well forever.  (I've been working in IT for decades)

Ah!

But I nab your 64K MP3's usually on Thurs nights (though they have been late the last few weeks).. since I can't always just listen w/o others bothering me etc etc.

I've been late in posting the podcast since I've been so preoccupied with the HPEDW (Hush Puppy Electronic Dog Whistle) project!  :)

But an "insider's" tip is that the audio files are ALWAYS posted just a very few hours after the podcast, since Elaine needs to start transcribing immediately and she has a horrific satellite link with limited bandwidth.  So SHE needs the 16kbps version as soon as it's available.  So... although the links are not up on the "Security Now!" page, if you just change the episode number from any recent episode, you'll get the audio.

For example... today's audio is already up on the server!  <g>

--//--

The short version of "the reason for 15khz" is that even canine hearing begins falling off not much higher than that... and also that even though tweeters may be RATED out to 20khz... you probably also know that their response it typically not FLAT all the way out there.  They, too, begin falling off.  So I wanted to stay inside of that zone as well.  And finally, I WANT people to be able to hear this thing... just a bit.  I think it's important for people to RESPECT the acoustic power that's being generated so that they treat both each other AND dogs hearing with the respect that it deserves.

As I expect you will learn once you start experimenting... you'll DEFINITELY get the CLEAR sense from hearing this thing that (a) it's actually somewhat scary.  You definitely don't want to be listening to it when it's pointed at you.  If it made NO PERCEPTIBLE SOUND -- rather than a somewhat ominously loud high pitched scream -- that "sense of danger" from it -- which I think is IMPORTANT for it to convey -- would be absent.

/Steve.

[Kyle Smith]

> ... And finally, I WANT people to be able to hear this thing... just a bit. I think it's important for people to RESPECT the acoustic power that's being generated so that they treat both each other AND dogs hearing with the respect that it deserves.
>
> /Steve.

I was hoping this was the reason. Well said, Steve.

--
Kyle Smith, MS, MD (retired)

[tz]

It was from US Speaker, but I don't have it in front of me.  But it did say "Powerline".

My Digikey order is in and I did both values of Inductors (and a few variable).  Paralleling the inductors will allow double the current.  The FET might be more interesting - I saw some other variants, but I think I can play with that one.  My drawer has some arduinos so if I have some time from my day job (automotive embedded) I might try the A/D tuning to the optimal frequency - with the variable inductors it can be tuned.  Or perhaps use a brightness detector :).  Or temperature sensor...

I got two (expect one might be lost in testing, else I'll make two).  US Speaker - from your link, I think they were $35 each.  Without the horn it might still work as a K-de'nying amulet.  I have a 12v 400W amp so I played with it using my Samsung Galaxy Player with some Mosquito tones (I can hear 17.5khz - but it isn't loud).  Leonore #3 required my typical Motorcycle earplugs at full volume, but the light bulb didn't turn on.  I could get the mosquito tone to do so.

(I have a cruiser, and don't put the detachable windshield up, so cyclesounds.com has a 200W 12v.  The tweeters are loud, I may get one or two more - since I have to hear the music while wearing 30db earplugs for the wind noise; but there are headphone-earplugs that work and I usually use, but less fun.  Sometimes I put on Bach BWV 500-800 believing that 'loud pipes save lives' even when they aren't exhaustive).

Now I have to figure how my ultrasonic humidifier works. Make dogs disembark and take care of the winter dryness from the heat...

[Steve Gibson]

TZ...

It was from US Speaker, but I don't have it in front of me.  But it did say "Powerline".

Ah, yes!  That's Al Kahwaty's company in Freehold, New Jersey. Definitely TOP of the line.  The real deal tweeters from CTS in the Philippines.  And those bigger tweeter drivers are REALLY quite nice.  I consider them top of the line.

His KSN-1005's are $18.95.  I just bit the bullet and bought four (they arrived today) since I want to (a) characterize the tuning spread required between speakers and (b) see if I can get some sense for how the pricey tweeters actually compare in performance to the $2 Chinese clones of the same speakers.

/Steve.

[bouwe...@gmail.com]

Wonderful Security now today, thanks for the updates on the the PDK, can't wait for more of the docs.

thanks 

steve

[Kindanyume]

On Wed, Dec 5, 2012 at 6:27 PM, Steve Gibson <steve....@gmail.com> wrote:
> Kindanyume...
>
>
>> LOL Indeed.. I've been listening since.. well forever. (I've been
>> working in IT for decades)
>
>
> Ah!

I can tell you don't remember talking before lol Can't say I
blame you since you deal with so many ppl.. and when asked about you
by anyone I simply describe you as having forgotten more about IT than
I can remember. :) (And I'm fairly well regarded as an expert in the
industry as well.. but I have to be honest.)

>
>> But I nab your 64K MP3's usually on Thurs nights (though they have been
>> late the last few weeks).. since I can't always just listen w/o others
>> bothering me etc etc.
>
>
> I've been late in posting the podcast since I've been so preoccupied with
> the HPEDW (Hush Puppy Electronic Dog Whistle) project! :)
>
> But an "insider's" tip is that the audio files are ALWAYS posted just a very
> few hours after the podcast, since Elaine needs to start transcribing
> immediately and she has a horrific satellite link with limited bandwidth.
> So SHE needs the 16kbps version as soon as it's available. So... although
> the links are not up on the "Security Now!" page, if you just change the
> episode number from any recent episode, you'll get the audio.
>
> For example... today's audio is already up on the server! <g>

Well then.. as soon as last wk's is finished (Listening was delayed
again due to more of my fight w/the CDN gov) but def good to know in
advance. In fact it just finished dl'ing. As for Elaine's link..
16k? OMG! I'd go insane! 16M DSL loop here is slow enough due to
crap upload (.8).. but 16k? damn... reminds me of when I was doing
beta testing on the last gen Courier modem.. only worse. Did she move
into the middle of the boonies?

>
> --//--
>
> The short version of "the reason for 15khz" is that even canine hearing
> begins falling off not much higher than that... and also that even though
> tweeters may be RATED out to 20khz... you probably also know that their
> response it typically not FLAT all the way out there. They, too, begin
> falling off. So I wanted to stay inside of that zone as well. And finally,
> I WANT people to be able to hear this thing... just a bit. I think it's
> important for people to RESPECT the acoustic power that's being generated so
> that they treat both each other AND dogs hearing with the respect that it
> deserves.
>
> As I expect you will learn once you start experimenting... you'll DEFINITELY
> get the CLEAR sense from hearing this thing that (a) it's actually somewhat
> scary. You definitely don't want to be listening to it when it's pointed at
> you. If it made NO PERCEPTIBLE SOUND -- rather than a somewhat ominously
> loud high pitched scream -- that "sense of danger" from it -- which I think
> is IMPORTANT for it to convey -- would be absent.
>
> /Steve.

Many tweeters are rated beyond 20K.. but most that we are more
commonly using are dynamic in design for HiFi. (The majority of my exp
w/such was high end hifi) They won't be particularly suitable for
this. The Piezo design however is less "pleasant" (for lack of a
better word) but can be very efficient and rated in some cases well
beyond 20K including being relatively flat at 20-25k. (Sorry I don't
have proper response and waterfall plots in hand for the model you
picked from Pyramid)

I had thought of that as a way of enhancing "safety" (which I deal
with regularly with firearms).. however canine hearing is more
typically reaching 60K.. way beyond even the best human hearing and
they tend to respond to much higher freq. Hence why we make
ultrasonic whistles. However given those facts and wanting a safety
measure to help prevent any abuses by "some moron" that gets their
hands on a PDK. (Which as we all know is enviable sadly). I had
thought of feeding in a dual tone signal.. perhaps on the same
amplitude.. but perhaps of a slight scale in power. That I would
think would still give some audible feedback at about 15k.. (though
upper hearing is commonly lost as we age etc. I can't hear 17K
anymore.. though yrs ago I could hear 22k) giving feedback while an
upper register could be more effective w/dogs. Also the upper freq
by it's nature is more directional in nature.. therefore helping to
control the dispersion by exploiting such acoustics.

Perhaps someone has info on the levels/freq generated by a dog
training whistle handy?

Granted I have not looked at the design aspects to give a dual output
yet.. though the tweeters we have looked at should have no issues
handling such. But hey it was def a thought while tied up w/other
things.



>

[tz]

Ah, but if you had two in sync, could it do this:

http://www.anl.gov/articles/no-magic-show-real-world-levitation-inspire-better-pharmaceuticals

[Kindanyume]

Ahh how true... though I don't know if the FDA would approve such
combined with a PDK :)

I did however forward that link to my wife and a few of her friends
whom work in that industry.

[Liquidretro]

I am looking to start ordering some parts for a beta build of this and the biggest question seems to be the tweeter.  Is there a link on what people are deciding to buy on this? I know this is a family of tweeters so several will work.  What I see in this thread is mostly links to large bulk purchases

[Steve Gibson]

Hi LiquidRetro...

I am looking to start ordering some parts for a beta build of this and the biggest question seems to be the tweeter.  Is there a link on what people are deciding to buy on this? I know this is a family of tweeters so several will work.  What I see in this thread is mostly links to large bulk purchases.

Many outfits carry the "Goldwood GT-1005"  Just Google that phrase.  And also "KSN-1005" which was the original Motorola designation.  The annoying thing is that the shipping cost it typically more than the component cost.

Here are some typical Amazon hits:

http://www.amazon.com/Pyle-PSN1167-Dispersion-Piezo-Tweeter/dp/B000EFMP7W

http://www.amazon.com/Pyramid-TW105-3-75-Inch-Watts-Tweeter/dp/B0013CFOBY

http://www.amazon.com/gp/product/B008I5R584

http://www.amazon.com/gp/product/B000HJ4RY4

http://www.amazon.com/Tweeters-Replacement-KSN1001A-Motorola-T1001-4/dp/B0034529LG

http://www.amazon.com/MCM-Audio-Select-53-800-Tweeter/dp/B008I5R4LM

The optimal TWEETER still needs to be widely "characterized" for use with this project.  The first need was to nail down the power amplifier.  We very nearly have one now ... though I remain unhappy about its lack of digital tunability.  (And when I'm unhappy, things tend to change.)

So PLEASE BE ADVISED that this project is still in an amorphous state with literally anything and everything -- except probably the tweeters -- subject to change.

/Steve.

[Jason Redepenning]

i would like one   to try it out  i have  2 dogs  and one barks all the time i would like to try one 

as  a  training tool.. 

thanks

jason redepenning

[Steve Gibson]

Everyone...

Photo: http://www.pyleaudio.com/1000/PLWT4.jpg

http://www.pyleaudio.com/sku/PLWT4/15-200-Watt-Surface-Mount-Piezo-Tweeter

http://www.amazon.com/PLWT4-1-5-Inch-Surface-Mount-Tweeter/dp/B00069R6KM

http://www.ebay.com/ctg/Pyle-PLWT4-3-Way-1-5-Car-Speaker-/72053582

These are LOUD and they work PERFECTLY with our high-power, fixed-frequency, harmonic power oscillator design with NO changes to the design.  They appear to the circuit to be identical to the KSN-1005 breed of horn-based tweeters.

They are essentially the power-end of the KSN-1005 breed tweeter without any horn.  They employ the so-called "inertia drive" where the piezo wafer is attached to the back of a rigid cone and, by flexing its own mass in and out, drives the cone in the opposite direction.

However... since they lack any sort of horn, they are not going to be very directional.  In a car, this is fine, since you just want to fill an small enclosed space.  So they cannot be "aimed".

However, they are SURFACE MOUNT, so I can imagine applications where you would rather have a dispersive sound generation -- for example to fill a backyard -- rather than a "aimed" solution.

Anyway... I promised someone here that I would look into them, and I'm glad I did.  For what they are, they work well and are 100% compatible with our deliberately finicky v2.2.x designs.  :)

/Steve.

[Liquidretro]

Thanks Steve, I placed an order and will wait on the rest of the design to stabilize before order more pieces.  I don't have a terrible barking problem but really just enjoy building stuff like this.  

[Kindanyume]

Nice as usual Steve,

I'd also toss in the idea that one could probably use one with a semi
horn made from the end of an older flashlight.. the typical 2" diam
style etc... not as good as a proper horn but it could help a fair
bit with aiming.

[birr...@gmail.com]

Hello! I was just about to place and order on eBay for a pair of these when I saw that shipping to Romania would cost $31.36. That's too much for me. :-(

Could you please recommend something cheaper? I saw 500W Chinese tweeters for as low as $1.59, but I thought it's better to ask you - more experienced - guys before buying junk.

Thanks!
Robert

[Steve Gibson]

Robert...

Hello! I was just about to place and order on eBay for a pair of these when I saw that shipping to Romania would cost $31.36. That's too much for me. :-(

Could you please recommend something cheaper? I saw 500W Chinese tweeters for as low as $1.59, but I thought it's better to ask you - more experienced - guys before buying junk.

Yeah. If those handle 500 watts of power, I'll swallow them whole (after sprinkling them with soy sauce)!

That's half a kilowatt.  Hah!!

Also... nowhere is there listed the technology used (electromagnetic or piezoelectric) the impedance or resistance, or the frequency range.  The side-view appears to show a wire-wound copperish coil... which, if that's what we're actually seeing, would mean that it's an electromagnetic speaker and NOT the breed of piezoelectric tweeter these designs assume.

The thing to do, Robert, is to search in eBay for: Piezo Tweeter

If you find something there whose price and shipping and all other terms works for you, post the link(s) here and we'll double-check them.

:)

/Steve.

[Kindanyume]

Robert.. (and any others that need this info)

Wow.... I just checked out that listing.. and talk about horribly written

"More sound Less Energy,with only 2.8V you can feel 97db of pure sound! "

This might sound great to anyone that does not actually understand
about speakers.. but it is essentially useless info. Same as the
"500W max power output". etc

I honestly advise to skip any listings that do not actually clearly
state what it is they are selling and only have such "hype" style
comments instead of actual specifications.

If in doubt just ask. I'm happy to help as I'm sure Steve is as well
as many others :)

[Brian Hall]

I found that the stranded wire leads connecting to the tweeters are of poor quality and were poorly soldered. Both leads broke off twice while gently handling. When I build the next iteration, I would like to replace the wiring with something a little higher quality. I don't know that much about speaker tech, but could I just solder on some of my 22AWG solid core wire for the speaker leads?

Brian Hall

[Steve Gibson]

Hi Brian...

I found that the stranded wire leads connecting to the tweeters are of poor quality and were poorly soldered. Both leads broke off twice while gently handling. When I build the next iteration, I would like to replace the wiring with something a little higher quality. I don't know that much about speaker tech, but could I just solder on some of my 22AWG solid core wire for the speaker leads?

The tweeter's connection wire is not critical. We're dealing with relatively low current (compared to, for example, big woofers) and such high driving voltages that gauge won't matter much.  I'm a fan of solid copper wire for interconnecting components on a perf board since it's sort of a structural component.  But I prefer to use stranded wire between any separate items that might need to move with respect to each other.

That said, though... electrically, whatever you prefer will be fine!

/Steve.

[birr...@gmail.com]

Thanks for the heads-up!

Steve, I did the search using those keywords, but I could only find piezo tweeters with 'big' horns. Ever since I saw these car piezo tweeters I decided to get those. The reason I think is obvious: their size makes them very easy to install in a small enclosure, thus making the whole device nice, small and truly portable. So, I don't know... I ordered all the other parts and I'm clueless about the tweeters.

[Steve Gibson]

Robert...

Thanks for the heads-up!

Steve, I did the search using those keywords, but I could only find piezo tweeters with 'big' horns. Ever since I saw these car piezo tweeters I decided to get those. The reason I think is obvious: their size makes them very easy to install in a small enclosure, thus making the whole device nice, small and truly portable. So, I don't know... I ordered all the other parts and I'm clueless about the tweeters.

Unfortunately, when it comes to generating sound, SIZE and the physics matters.  (How many wives during the last century have begged their husbands to somehow choose smaller (and less visible) speakers for the main music system?  But you cannot produce good bass (which have looooooong wavelengths) with small speakers.  It's not physically possible.

Similarly... we don't really know yet how the tiny Pyle surface mount tweeters compare to the horn tweeters. But there's a reason the tweeters have horns.  That plastic was not used, and wasted, for no reason.  It has very definite and important physical properties.

So... while you can definitely make something loud with them... it's not yet clear what the tradeoffs will be.

/Steve.

[Kindanyume]

Sorry to interject Steve.. but that while true on the surface is not
100% accurate.

Now I agree that as a rule that is true.. and for purposes ofr the PDK
etc.. it is irrelevant of course.

However that said it is possible to get very very good bass from a
smaller driver.. but the design is key to say the least. if we are
talking the typical POS speaker in a 'clock radio" etc.. for real
'good' sound everyone is SOL. However it is quite possible to get
very good bass down to under 40hz from even a 6.5" driver if designed
right. And it can be done to hit a 20hz from an 8" driver. of
course again design is key there to say the least.

My own reference speakers I designed will hit 22hz at -3db (and 20hz
at only -4) from an 8" driver. (granted that is a large very
complicated multi-phase modification of a 4th order design to
"simplify it"). However other designs such as the 6.5" (real world
closer to 7) extremis drivers (sadly discontinued now) were amazing
for good bass in a very small cabinet due to the design of the driver.
That said the accuracy is very good but I still prefer my focal
polyglass 8" drivers in the end. (oh and no.. my design is not
available commercially and was a "1 off".. and were a whore to both
design and build. far far worse than almost any other speaker cabinet
design IMO. Oh and they weigh over 150lbs each easily. Don't ask..
it's again a long story)

And now.. my blurb is over.. back to our regular programming :)









On Tue, Jan 8, 2013 at 4:19 PM, Steve Gibson <steve....@gmail.com> wrote:

(snip)

> But you cannot produce good bass (which have looooooong
> wavelengths) with small speakers. It's not physically possible.
>

(snip)
> /Steve.

[Steve Gibson]

Sorry to interject Steve.. but that while true on the surface is not 100% accurate.

The CONCEPT was 100% accurate, which is what I was trying to convey.  Due to the physics involved, a two inch small-excursion driver can generate very loud 10 khz sound... but it cannot generate very loud 100 hz sound.  You know that wavelength matters.  

As does horn / enclosure design.  So your note didn't contradict mine, in confirmed and demonstrated it.

/Steve.

[Kindanyume]

Oh I agree.. it's not my intent to contradict per se.. but simply to
elaborate on that subject.. As I said overall irrelevant to this
discussion overall.. Though the fact that the horn design does come
into play in some ways for that as well. As for the 2".. I hate to be
a smartass here but yes it could. However the real world design of a
driver with onl 2" 'face' would be.. well beyond retarded given our
current technology etc :) (Though hey it would make one great SiFi
version for some good author!)

As for 100khz.. and loud.. assuming the design is sound it sure as
hell can! lol (made my ears ring on more than one occasion from
such.. to the extent is was worse than most firearms on the range as
well)

[Kyle Smith]

Steve,

Any pair of high quality in ear headphones will produce much more accurate base than virtually any sized open air speaker. The wave lengths of audio at say 20Hz, when conducted through air at normalized ambient pressure; i.e., 1 atm, are so much larger than even a 24" subwoofer, as to render the point mutt, since the 24" diameter driver does not equal but a very tiny percentage of the wavelength at subwoofer frequencies. 

It can be said of audio in the LFE frequencies, that the only things that matters is the that a driver be able to produce the desired SPL in the desired environment, with acceptable fidelity. Now, if you wish to have the very floor beneath your feet rumble such that you achieve a visceral impact on your body, you will be obliged to use a driver that can match well the impedance of your floor, and not the air pressure level on your tympanic membrane, which is after all, the more typical target for a high fidelity system, and just happens to be much smaller than any but the drivers used with in-ear canal headphones. 

Thus, a drivers diameter is not a significant parameter, from the stand point of matching in some harmonic way to the target audio frequency, until we get well into the ultrasonic frequencies. In fact, the design criteria of most drivers usually place a high value on a drivers flat response across its operating range, and taking into account the target environment's acoustic impedance, with respect to the volume of air between the driver and the ideal listening position. Given an optimal acoustic environment virtually any diameter of driver is capable of faithfully reproducing the low frequencies that are generally produced by those amperage draining, huge subwoofers, seen in the cars of youngsters, who don't have a clue as to how best to reproduce the sounds which they are largely experiencing through visceral conduction, rather than any coupling with their tympanic membranes. Indeed their intent is not so much that they hear the thumping drone, as it is that the entire neighborhood should be treated to the waisted energy emitted into the outside of their vehicles, that adds not a wit to their own listening experience, other than if you consider it part of their enjoyment to impart to their captive audience a sense of ah with respect to how much money and effort it took them to achieve such a muddy thumping sound outside of their vehicle.

Note no adolescents were hurt in the writing of this missive. But, all too many adolescents are driving themselves much more quickly on the path to very real permanent hearing damage, as a result of the insanity that befalls all too many of us in our teenage years. Audio marketing to this segment of the population is truly without any concern for the health of their target demographic. They are out to rob our young adults of both their money and their exceptional high frequency hearing. And to make matters even worse, these purveyors of audio junk, empower their clients with a means by which they can pollute the audio environment for a considerable distance from their crib or vehicle.

Best wishes,
--

Kyle Smith AG2F

air...@me.com

[Steve Gibson]

Kyle...

Any pair of high quality in ear headphones will produce much more accurate base than virtually any sized open air speaker.

Ah... but we were talking specifically about open air conditions.

Pull the headphones an inch away from the listener's head and virtually all of the bass disappears.  And "in ear" phones have the same lack-of-bass problem.  Headphones are able to provide bass only because, when pressed up against a person's head -- and SEALED -- an ENTIRELY different, non-open-air set of conditions apply.  In an entirely sealed environment it is certainly possible to pump low frequencies.  But that's not what we were talking about.

/Steve.

[Kyle Smith]

Steve,

I have no issue with that statement. In fact, I specified that they would work only in the acoustic environment. So we agree on that point. My objection was in inferring that simply because of a drivers large diameter in relation to the wavelength, they would have some advantage over a smaller driver. But, the wave lengths of sound in a sub woofers operational range are enormous compared to even a huge driver. Therefor, the advantage is not critically dependent on the ratio of the driver diameter to wavelength, since that ratio does not appreciably change when comparing a 24" super subwoofer, to let's say an 8" woofer. They both represent insignificant fractions of the audio wavelength being generated in air. 

So we have to look at other factors for the explanation as to why one might prefer larger of smaller diameter drivers. Excursion does play a significant role, if the driver is stiff enough to oscillate at the target frequency, without distortion induced by the outer sections of the driver lagging behind the inner voice coil, which becomes more pronounced the larger the diameter of the driver.

Yet I'm sure we are actually saying the same thing, and the topic has drifted from the little piezo drivers of these projects. My only intention, initially as I wrote my previous post was to point out that the ratio of driver diameter to say a 20Hz sine wave in air was so small a number as too make comparisons based solely on that metric specious, since the ratios simply do not change significantly enough to alter the dynamics of a driver with a diameter even half the size of another at those low audio frequencies. 

Certainly if you need to move significant volumes of air to produce a given SPL at a certain distance, then the bigger your piston is, and the greater the excursion it makes per cycle, the more likely you are to reach that target SPL in the open air. 

For my money, I would rather expend funds in the perfecting of the listening environment, such that my enjoyment can be had with great fidelity without the need for large amperage hungry drivers, with more distortion than can be obtained by limiting the amount of air that needs to be displaced for a given perceived signal amplitude. 

Perhaps my age is a factor, given that I have not desired to attend a large venue for many years now. And my use of limited listening area keeps me very satisfied, while preventing my audio from leaking out into the peaceful neighborhood in which I live. Just because I love to listen to great jazz artists does not mean that my neighbors share my passion or the time at which I care to listen to it. 

I am looking forward to your new frequency agile treble shooter design. I have found that in my moderate volume tests, the waveform is quite crucial in motivating my dogs to spontaneously leave the my room. Sometimes, however, I have noticed that they will huddle around me, as if for protection when certain waveforms are played. While other wave forms will cause them to leave immediately. In any event, in neither case do they continue to howl, which I have managed to do with PD, Audacity, and a simple pair of bookshelf studio monitors, and absolutely no audible sound (at least to me.). Of course, training ones own dogs is not at all the same as trying to stop a neighbors pet from yapping. But then I'm surrounded the more part by ocean water, and only notice others dogs, because my own dogs can hear their faint barking, and seem obligated to reply. 

Best wishes,

--

Kyle Smith AG2F

air...@me.com

[birr...@gmail.com]

Hi!

Last night I posted a reply, but it was deleted. Why? (it contained a few links to tweeters, since you kindly offered to double-check my choice)
How can I post it so that it doesn't get deleted again?

Robert

[Kyle Smith]

Robert,

I do all my reading in this group by use of individual emails 1 per post, and I can confirm that I did receive and still have a copy of your post within this thread.  I don't find the Google reader any better than simply keeping my own copy of all threads within my mail server, where they do not disappear. Don't know that this helps your situation at the moment, but if you used email in the future, at least you'd be blissfully ignorant of the quirks within Google Groups. 

Best wishes,

--

Kyle Smith (AG2F)

air...@me.com

[birr...@gmail.com]

On Wednesday, January 9, 2013 5:19:33 PM UTC+2, Kyle Smith wrote:

Robert,

I do all my reading in this group by use of individual emails 1 per post, and I can confirm that I did receive and still have a copy of your post within this thread.  I don't find the Google reader any better than simply keeping my own copy of all threads within my mail server, where they do not disappear. Don't know that this helps your situation at the moment, but if you used email in the future, at least you'd be blissfully ignorant of the quirks within Google Groups. 

Best wishes,

--

Kyle Smith (AG2F)

air...@me.com

Hello Kyle! OK, that means that I only have to wait for a recommendation to the links I posted.

Best wishes to you too!
Robert

[Steve Gibson]

Hi Robert!

Last night I posted a reply, but it was deleted. Why? (it contained a few links to tweeters, since you kindly offered to double-check my choice)
How can I post it so that it doesn't get deleted again?

I recall seeing a posting of your REFERRING to that missing post, but I never saw the posting itself.

In any event, I didn't delete it, and so far as I know, I'm the only person who can.

I did -- a few days ago -- do some "housecleaning" of old dead topics from a year ago that were just collecting dust.  And others posting that they wanted to beta test who have since written to me again where I can collect names.  But I'm sure that none of them were yours.

/Steve.

[birr...@gmail.com]

Hello!

Here are the names of the models I posted (no links this time): KHS309, KHS311M, KHS108, KHS107, KHS106. Just put in Google these models plus the word 'piezo' to find the specifications of each one.

The reason I listed these are that I found them at a local (i.e. Romanian) retailer which makes buying easy and more specifically these ones because they are nice, round and relatively small in size. There are a bunch of other 'horned' models available too.

Regards,
Robert

[Steve Gibson]

Robert...

Here are the names of the models I posted (no links this time): KHS309, KHS311M, KHS108, KHS107, KHS106. Just put in Google these models plus the word 'piezo' to find the specifications of each one.

What about the KHS105 or KHS105A??  That one *IS* the exact speaker we've been talking about!

The KHS106 looks like the closest one that would definitely be okay. But the KHS309 looks okay too!

/Steve.

[dilly dobbs]

Is it possible to use a device like this for rodent control?   Like bats ? 

Sorry for going off topic 

Thanks 

Ryan 

[Steve Gibson]

Is it possible to use a device like this for rodent control?   Like bats ?

Yes, very.  Rodents -- both ground and airborne -- have extremely sensitive high-frequency hearing.  This would definitely keep them away.

Sorry for going off topic

Not far, though.  :)

/Steve.

[Kindanyume]

Indeed and the 3rd volunteer here for testing will be on dogs and
squirrels which have caused major damage in his garage

[birr...@gmail.com]

Thank you! I'll buy whichever will be in stock. If it's possible I'll buy all three (105A, 106 and 309).

Night night!

[David Doyle]

Hi Folks,

Any thoughts about  Goldwood GT-1005 Wide Dispersion Piezo Tweeter http://www.parts-express.com/pe/showdetl.cfm?partnumber=270-011 ?

Thanks

[Kindanyume]

good freq response esp for any design with a tone higher than we can
hear. Lower sensitivity however. Slightly lower power handling.. but
I would think it should still work and the price is right as well :)

However it appears that the horn is not the same horn as the Motorola
knockoffs.. and is described as wide dispersion which is the opposite
of what we want here as a rule. (Also w/o any plots of it's actual
performance of course). Could be handy in multiples in a fixed
location design though. :)

[Steve Gibson]

David...

Hi Folks,

Any thoughts about  Goldwood GT-1005 Wide Dispersion Piezo Tweeter http://www.parts-express.com/pe/showdetl.cfm?partnumber=270-011 ?

Yep.  That *IS* the one to use.  It's the one we've all been buying.  It's the one the circuit has been designed around.

/Steve.

[Kindanyume]

Interesting Steve since based on that pic the horn does not look the same

[Kindanyume]

Not to mention the specs are diff than the pyramid model as well. It
seems there are many variants of the same base then.. should prove
interesting when testing to see any differences

[Steve Gibson]

Interesting Steve since based on that pic the horn does not look the same

Does not look the same as what?  It looks identical to all of the Motorola/CTS  KSN-1005 derived tweeters I've seen...

They all pretty much look like this one.

/Steve.

[Kindanyume]

Hmm.. I'll do a more detailed comparison to the other pix I have here (my pyramid versions are not in hand yet argh)

[jason]

How can I Unscribe your  emails  for this  forms   not shur how  I got this  in my email

I do want try out   the project on my  corgis  as training tool thou  I have one corgi 

That barks all the time about any thing  .  

If any help so I get it   but do not want emails coming thou all the time  

Thanks you much and keep up the good work

jason

[Steve Gibson]

Jason...

You should find a "Gear" (meaning settings) in the upper right hand region of the Group's window.

Go there to unsubscribe from notifications.  :)

/Steve.

[David Doyle]

Thanks Steve

[Jim Unroe]

I ordered this GT-1005 tweeter from Amazon for $439 with free shipping.

http://www.amazon.com/gp/product/B0013CFOBY

When it arrived, much to my surprise, it was a package to 2 tweeters!

Jim

[Kindanyume]

Wow.. only $439? What a deal!

lol

Sorry.. couldn't resist :)

[Jim Unroe]

I wouldn't have been able to resist either. That should have been $4.39 (I had to refill my keyboard with decimal points and periods yesterday. It's almost as bad as my printer is with ink).
Jim

[Kindanyume]

lol.. yeah those damn keyboards,.. they sell em cheap.. only to gouge
on the decimal points and periods we are forced to buy at highly
inflated prices.. and of course are not interchangeable! :)

Btw you can cheat and refill the main period key by subbing in the
decimal point key from the number pad. Most keyboards fall for that
trick to save you some $.. but not all... beware the "locked" keyboard
types!