May 8 - Idea - Tapped Horn Upgrade - AVS Forum | Home Theater Discussions And Reviews
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post #1 of 28 Old 05-08-2009, 01:27 AM - Thread Starter
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quick history of tapped horns: 1/4 wave resonance creates so much pressure the driver can't overcome it and doesn't move resulting in little output.

Danley's solution - put the driver away from the pressure maximum where pressure is less so the driver can move.

It works. But now you have all sorts of out of phase cancellations.

do not despair ... Vas solved the problem.

Instead of having a horn open at one end and closed at the other we build a horn open at both ends !

We fold it in half and mount the driver at the middle - so far what we have produced is functionally identical to a conventional horn.

now we move the driver off-center so its not on the pressure maximum - now what we have is functionally identical to a tapped horn.

and NOW ! we modify our horn cabinet such that the two sides of the horn don't exit at the same side of the cabinet but at the opposite sides. this creates a phase shift between them that cancels out the original phase shift introduced by mounting the driver off center ! ! !

in other words we have preserved the output efficiency of a tapped horn but eliminated the nulls due to out of phase cancellations of course this will only work in one direction and you will have to AIM the subwoofer at your listening position for it to work but still ...

also in my version the back of the driver is sealed. so technically its not "tapped" but the whole "tapping" is just a way to save on cabinet construction. the point of tapped horn is not tapping - its moving the driver out of the pressure maximum.

is everything clear ?

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post #2 of 28 Old 05-08-2009, 04:27 AM
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Quote:


is everything clear ?

Yes. The end result is called a Bose Acoustic Wave Cannon.

http://www.diyaudio.com/forums/showt...501&highlight=
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post #3 of 28 Old 05-08-2009, 06:55 AM
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may 8, 09:56, press delete.

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post #4 of 28 Old 05-08-2009, 11:22 AM
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Exhibit A (Danley TH-SPUD)
* Image deleted my original poster

Exhibit B (Danley TH-SPUD)
* Image deleted my original poster
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post #5 of 28 Old 05-08-2009, 04:24 PM
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"1/4 wave resonance creates so much pressure the driver can't overcome it and doesn't move resulting in little output."

I think you missed the boat right out of the gate.

The pressure comes from the driver, and the fact that it's high means good acoustic loading & efficiency.

It's like saying a port is bad because the pressure it creates in the enclosure keeps the driver from moving.

Noah
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post #6 of 28 Old 05-08-2009, 04:59 PM
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wow mynym! nice pull!

any chance you have one of those for the th-50?

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post #7 of 28 Old 05-08-2009, 06:25 PM
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Quote:
Originally Posted by mynym View Post

Exhibit A (Danley TH-SPUD)


Exhibit B (Danley TH-SPUD)

Now thats a REALLY good way to encourage manufacturers to participate in forums like this.

Just throw their hard worked-patented plans out for all to see.

Maybe that is why so many loudspeaker designers do not participate in forums and share ideas-because they may get stolen and their work ends up being thrown out for free.

Maybe you would like to work for free and have your ideas stolen.

Danley Sound Labs

Physics-not fads
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post #8 of 28 Old 05-09-2009, 06:44 AM
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Quote:
Originally Posted by Ivan Beaver View Post

Now thats a REALLY good way to encourage manufacturers to participate in forums like this.

Just throw their hard worked-patented plans out for all to see.

Maybe that is why so many loudspeaker designers do not participate in forums and share ideas-because they may get stolen and their work ends up being thrown out for free.

Maybe you would like to work for free and have your ideas stolen.

Uh, you're aware anyone who wants to can browse through patents and see all their secrets right? If you want to keep something secret, you don't patent it. You keep it as a trade secret.
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post #9 of 28 Old 05-09-2009, 09:10 AM
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Originally Posted by Stereodude View Post

Uh, you're aware anyone who wants to can browse through patents and see all their secrets right? If you want to keep something secret, you don't patent it. You keep it as a trade secret.

Exactly

Wand who will "steal" this design , a few DIY addicts. I am sure they left out a few "minute" details out so even if you build a replica it will not match the oroginal.

Ask yourself mortal , do you have as much displacement as me ? The answer is no unless you have a Windmere fan sub.
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post #10 of 28 Old 05-09-2009, 09:46 AM
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Originally Posted by TheEAR View Post

And, who will "steal" this design , a few DIY addicts. I am sure they left out a few "minute" details out so even if you build a replica it will not match the oroginal.

It's not even "stealing". Patents exist to prevent someone from making money by commercially using another person's patented idea(s). This occurs via giving the person holding the patent legal recourse against the person infringing. A patent doesn't prevent someone from using another person's patented idea for their own use because there's no commercial infringement.
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post #11 of 28 Old 05-09-2009, 10:19 AM
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Quote:
Originally Posted by Stereodude View Post

It's not even "stealing". Patents exist to prevent someone from making money by commercially using another person's patented idea(s). This occurs via giving the person holding the patent legal recourse against the person infringing. A patent doesn't prevent someone from using another person's patented idea for their own use because there's no commercial infringement.

Of course, you're correct, technically speaking, but...it should be left to the inventor to publish or not to publish the information in a public forum.

Tom has generously posted in these and other DIY forums over the years, and that's where the real value lies, not in going against his wishes just because it's legally doable.

I disagree with Ivan's approach. It should be enough to mention that Tom would rather the post be edited out and those who are truly interested in building their own clone of his invention look forward to Tom's input, as he sees fit to offer it.

Although I agree that most commercial subwoofer enterprises don't participate in forum discussions, it's naive to think that they aren't ever-present as lurkers. It's a 2-way street. They nick as much from us as we might from them.

I've been along for the ride from the beginning. The best drivers in the world were all partially designed by and/or introduced through and for DIYers.

Over the evolution of the state of the art, the F3 has extended by 2 octaves. By any measurements regime one can name, DIY creations sit firmly at the top of every list.

Referring to us as a group in the light that we're a bunch of rubes who crudely copy existing designs is condescending and a fallacy.

Still, I would never post information without asking permission from the inventor, whether or not it's legal otherwise is irrelevant. It's the information age, not the ignoramus age.

Bosso
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post #12 of 28 Old 05-09-2009, 11:04 AM
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Quote:
Originally Posted by Ivan Beaver View Post

Now thats a REALLY good way to encourage manufacturers to participate in forums like this.

don't be such a donkey. if any of YOUR real competitors want to reverse engineer the sub for commercial purposes, they will just buy one and slice it open.

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Just throw their hard worked-patented plans out for all to see.

if this was from internal documents, i might agree. but if it is from a patent application, it's public domain.

Quote:


Maybe that is why so many loudspeaker designers do not participate in forums and share ideas-because they may get stolen and their work ends up being thrown out for free.

no. that would be because all they have is marketing and this is diy build seminar, not marketing seminar.

Quote:


Maybe you would like to work for free and have your ideas stolen.

that is what we have copyright and patent law for at the highest level and confidentiality agreements for at the next level down. take a pill man.

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post #13 of 28 Old 05-09-2009, 11:12 AM
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Quote:
Originally Posted by bossobass View Post

Of course, you're correct, technically speaking, but...it should be left to the inventor to publish or not to publish the information in a public forum.

wrong. once patented, it is public domain. anyone can post it anywhere. that's the benefit to the public good. the private good is 17 years +/- of profit protection.

Quote:


Tom has generously posted in these and other DIY forums over the years, and that's where the real value lies, not in going against his wishes just because it's legally doable.

good point.

Quote:


Although I agree that most commercial subwoofer enterprises don't participate in forum discussions, it's naive to think that they aren't ever-present as lurkers. It's a 2-way street. They nick as much from us as we might from them.

probably more!

Quote:


I've been along for the ride from the beginning. The best drivers in the world were all partially designed by and/or introduced through and for DIYers.

good point!

Quote:


Over the evolution of the state of the art, the F3 has extended by 2 octaves. By any measurements regime one can name, DIY creations sit firmly at the top of every list.

here here!

Quote:


Referring to us as a group in the light that we're a bunch of rubes who crudely copy existing designs is condescending and a fallacy.

except for me. i may be a rube. btw, wtf is a rube?

Quote:


Still, I would never post information without asking permission from the inventor, whether or not it's legal otherwise is irrelevant. It's the information age, not the ignoramus age.

trying to coordinate information release across thousands of posters is impossible. it is going to happen. deal with it.

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post #14 of 28 Old 05-09-2009, 01:19 PM
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Originally Posted by LTD02 View Post

wrong. once patented, it is public domain. anyone can post it anywhere. that's the benefit to the public good. the private good is 17 years +/- of profit protection.

The posted drawing isn't from a patent application. Read the 'Proprietary and Confidential' notice at the left side of the Title Block.

Patent app drawings are a completely different format.

Bosso
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post #15 of 28 Old 05-09-2009, 03:41 PM
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Originally Posted by bossobass View Post

The posted drawing isn't from a patent application. Read the 'Proprietary and Confidential' notice at the left side of the Title Block.

Patent app drawings are a completely different format.

Bosso

So where exactly do you think mynym got the drawing from?
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post #16 of 28 Old 05-09-2009, 03:50 PM
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Someone posted it in a DIY audio forum on tapped horns. No clue where it originated from.

Ask your doctor if DIY is right for you. Side effects of DIY may include anxiety, elevated blood pressure, lightheadedness, rapid heartbeat, skeletal muscle flaccidity, euphoria, psychological dependence, insomnia, confusion, blurred vision, impulsivity, uncontrolled or repeated movements.
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post #17 of 28 Old 05-09-2009, 04:01 PM
 
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I do not know where he got the drawing from, but I have seen that drawing (several months ago) floating around on other forums.
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post #18 of 28 Old 05-09-2009, 04:17 PM
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At least Vas provides us all his ideas for free!
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post #19 of 28 Old 05-09-2009, 04:34 PM - Thread Starter
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Quote:
Originally Posted by noah katz View Post

"1/4 wave resonance creates so much pressure the driver can't overcome it and doesn't move resulting in little output."

I think you missed the boat right out of the gate.

The pressure comes from the driver, and the fact that it's high means good acoustic loading & efficiency.

It's like saying a port is bad because the pressure it creates in the enclosure keeps the driver from moving.

Bro that's exactly what i thought and why i was saying Tapped Horns are crap and why i got banned from Diy Audio.

but when i modeled a horn in hornresp it does look like it happens - REDUCTION of output at resonance.

let me make an analogy - an amplifier driving a resistor. with zero ( short circuit ) resistor amp can deliver zero power. with 4 ohm resistor it delivers maximum power and with an infinite resistor ( open circuit ) it again delivers zero power.

regular speaker is almost like a short circuit - there is virtually no load to transfer power to. a properly optimized horn is like a 4 ohm resistor ( such a horn produces on the order of 110db/watt ! ! ! ) but a resonance that is too strong in the horn is beginning to look like an open circuit and again not much power can be transferred.

the trick is to get it EXACTLY RIGHT and ACROSS THE OPERATING RANGE and IN A REASONABLE SIZE ENCLOSURE.

the point of tapped horn is it TUNES the STRENGTH of the resonance ( not the frequency ! ! ! ) for optimum loading !
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post #20 of 28 Old 05-09-2009, 05:45 PM - Thread Starter
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Quote:
Originally Posted by mynym View Post

Exhibit A (Danley TH-SPUD)

Exhibit B (Danley TH-SPUD)

That's something completely different from what i am talking about.

Quote:
Originally Posted by Uklit View Post

Yes. The end result is called a Bose Acoustic Wave Cannon.

http://www.diyaudio.com/forums/showt...501&highlight=

i am actually quite interested in what design Bose uses but i can't view the attachments at DiyAudio and the thread is way too long ...

could you post a diagram over here ? and maybe paste the relevant part of text that explains it ?
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post #21 of 28 Old 05-10-2009, 12:40 AM
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Quote:
Originally Posted by bossobass View Post

The posted drawing isn't from a patent application. Read the 'Proprietary and Confidential' notice at the left side of the Title Block.

Patent app drawings are a completely different format.

Bosso

well, if it is an internal document, then i would say...perhaps we should take it down. that's not cool.

if it is in any way public domain, then posting is fine, but if it was stolen, then i suggest it be taken down.

we can't control every other board, but we can be cool here.

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post #22 of 28 Old 05-10-2009, 07:58 AM
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Quote:
Originally Posted by Stereodude View Post

So where exactly do you think mynym got the drawing from?

I have no idea, but it's moot.

I respect Tom Danley. He's at the very top of my list regarding low frequency reproduction. I enjoy all of his posts, which, BTW, contain more specific and useful information than any principal of a commercial concern has ever posted, except maybe for Dan Wiggins, who is sorely missed on all the public forums he used to frequent.

If he objects to the posting of specific Danley Sound Labs info, it should be respected and the post should be amended, not argued from a legal standpoint. It's a no-brainer.

That's just my opinion, FWIW.

Bosso
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post #23 of 28 Old 05-10-2009, 09:32 AM
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Ditto to bosso's post.

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post #24 of 28 Old 05-10-2009, 10:37 AM
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WOW. I would have never thought my post with the TH-SPUD plans would have caused so much controversy. They've been around for over 6 months and have been talked about over and over in just about every forum except for AVS.

If you'd like me to remove them. Let me know but you better have a conversation with the folks over at audioholics and diyaudio as they've got at least 100 separate forum posts going with pretty heavy discussion, including that from Tom Danley:

http://www.diyaudio.com/forums/showt...5&pagenumber=2 (TH-SPUD specific clone discussion [This guy managed to squeeze three octaves between 15hz and 120 hz!])

http://www.diyaudio.com/forums/showt...threadid=97674 (3300+ replies regarding tapped horn discussion)

http://www.hometheatershack.com/foru...d-th-spud.html (another TH-SPUD clone)

http://forums.audioholics.com/forums...ad.php?t=49678 (More discussion and the source of the plans)

....
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post #25 of 28 Old 05-10-2009, 10:57 PM
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"but when i modeled a horn in hornresp it does look like it happens - REDUCTION of output at resonance."

The operating principle of horns is acoustic impedance matching, not resonance.

They may have them, but they're undesirable side effects.

Noah
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post #26 of 28 Old 05-10-2009, 11:06 PM - Thread Starter
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Quote:
Originally Posted by noah katz View Post

"but when i modeled a horn in hornresp it does look like it happens - REDUCTION of output at resonance."

The operating principle of horns is acoustic impedance matching, not resonance.

They may have them, but they're undesirable side effects.

no sh1t.

how does that help ?
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post #27 of 28 Old 05-11-2009, 04:52 AM
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ivan reports the docs are confidential internal docs, so please take them down.

i was more than juiced to see them, but i have respect for ip. we can't control the whole web, but we can be cool here.

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post #28 of 28 Old 05-11-2009, 03:40 PM
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I feel like I'm in a time warp..


Quote:


It is my understanding that the DIY’r can build anything they want to, patented or not, as long it is not for profit.

If people or companies make Tapped horns and use them for profit in a concert system, or makes and sells them, that is patent infringement. Assuming the Patent office agrees it is an acoustically “new” thingy, then, like any company, it is necessary to address those things but that is not my area or desire.
My wish would be that people try / listen to our stuff, put it next what there used to and then after a through comparison / audition, buy it haha.
Anyway, I should get back to work, I’m working on something new.
Best,

Tom Danley

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