Yep. No reason to use a line array waveguide for a single compression driver that i know of....
Well, in my case using steep linear phase xovers, as long as I have solid f-3 response at xover frequency, I've found i don't need to be concerned with response further down, at all. Look at the xover on latest build between sub (blue) and main-low (orange) at 100Hz and you'll see what i mean.
That's for home use, when FIR delay can be tolerated.
For live sound when delay can't be tolerated, I wouldn't have concern with more than an octave of overlap, mains to sub.
Because then I shoot for an acoustic 4th order xover, down 24dB at one octave.
That's going to take at least a second order electrical xover, where voltage required one octave down is 1/4th, and power is 1/16th. If it takes a 3rd order electrical, of course halve those numbers....getting down to nothing iow...
So I just can't see that the low-main driver is being pushed much,( or really providing much output) past an octave down.
Maybe solid output is required two octaves down if someone is trying to achieve a second order (or first, yikes!) acoustic xover, sub to main.....
but to me that idea seems completely at odds with a speaker built for higher SPL.
Multi compression driver is required if you need more output than a single compresion driver can provide (live mic'ed cymbals come to mind as difficult material). The large coaxial ring radiator drivers are more efficient than normal compression drivers so represent the greatest single driver output posible, if this is enough for your application it will be higher fidelity than an arrayed HF solution. Even the J7 has a far from perfect frequency response with lots of resonances in the HF, this is the price to pay for combining multiple HF drivers. Easy to work from the expected sensitivity, power handling, audience distance and target SPL to see what output you need from the box and if a single driver can manage it.
Patents are funny there is a lot of back and forth on the Danley patents but its important to remeber there are no patent police you would have to be sued and it would have to be worthwhile to do so. I would prefer it if we just didn't talk about such things as it encourages self censorship and for almost all our activities it is not a realistic concern.
Patents are funny there is a lot of back and forth on the Danley patents but its important to remeber there are no patent police you would have to be sued and it would have to be worthwhile to do so. I would prefer it if we just didn't talk about such things as it encourages self censorship and for almost all our activities it is not a realistic concern.
The comments I made above were actually for the benefit of the DIY community with regard to multiple entry horns (MEHs). I have always tried to "do the right thing, whenever possible". Not infringing on someone else's rights--in this case, the right of exclusive economic gain from one's inventions. I work hard to stay away from such transgressions. i assume that others think the same way, since it is a fair reward for the inventor given by governments.
In the case of the MEH, there are two patents. One patent (US6411718) is expired and one is still in force (US8284976) until 6 November 2029 in the USA.
Why are there two patents, and what is the difference between them? (A cardinal principle of patents is that one cannot patent the same invention twice--in series--in order to extend patent duration.) Unfortunately, this appears to be the case in the second patent, US8284976, which to me appears to attempt to do exactly the same thing as US6411718 (now expired). The only substantive difference between the two patents is this clause, added to the second patent:
So the original owner of the US6411718 patent (i.e., not Mr. Danley) allowed his patent to expire in 2014 due to the business owner's failure to pay the ongoing legal fee to keep the patent in force. After about two years of expiration, even the original patent owner cannot petition the patent to be reinstated. So in 2016, the rights to the MEH became free and clear--public information. That's the key for DIYers in the US (and I assume elsewhere). That means that DIYers can use the information in that US6411718 patent to their heart's delight, and without any remorse.
The discussion that I added, above, is that with the second patent, if a DIYer attempts to use the typical electrical filters used to separate "ways" in a multiway loudspeaker, generally, you'd be infringing on the second patent, US8284976. There is an easy way to avoid this situation, and it is the way that at least the woofer low pass is designed in the SH-50 (i.e., a design that whose patent has expired).
So why all the fuss? Two things:
1) The expired US6411718 patent is extremely useful to DIY loudspeaker builders because of the resulting physical properties of the loudspeakers produced:
- inaudible modulation distortion with respect to using the same drivers in direct radiating mode
- full-range point source capability
- extremely flat overall phase response
- extremely high efficiency (implying very low power needs)
- small size for a fully horn-loaded loudspeaker,
- full-range controlled directivity, and
- the ability to use less expensive drivers-if that is a design goal.
2) DIYers and even loudspeaker design engineers are apparently creatures of habit and will not reconsider how they design the crossover filters in their MEHs--which they are apparently treating just like multiway/multiple aperture (i.e., typical multiway loudspeaker designs). This is not only completely unnecessary for MEHs for their effective low-pass filters, it's actually illegal (in the USA and other countries). My message to these DIYers is "don't do it that way". In fact, the SH-50 woofers are not done that way, and it does just fine up to 127 dB/1m continuous--using its passive dividing networks (i.e., crossovers).
All of my comments, above, having to do with patents amount to this:
- don't infringe (because you actually don't have to), and
- use better-suited dividing networks for MEHs that make use of their inherent performance advantages.
I see line sources as useful nowadays because of the advantages of a single driver itself in terms of potentially very low cost, flat amplitude and phase response, very good horizontal polar directivity, and wide frequency range, etc. (I'm thinking of AMTs here). But their Achilles heel is vertical directivity--which is way too narrow coverage angle. They also don't have the SPL output of ring radiator or dome diaphragm compression drivers on horns--even when the AMT is horn loaded. They really can't make it up to 120 dB @1/m.
Chris
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I think op was refering to planar array waveguides which turn a compression driver into a line source. But in the past danley has claimed his horns that use multiple rear compression drivers match the wavefront curvature you would expect in a non truncated horn so this is a bit more complicated than using just line sources at the rear.
I have some thoughts on how to go beyond danley designs for output and fidelity and think a hybrid of this wavefront curvature approach and the eaw Anya hf array is the way forwards as using Hugens construction principle we can construct such a curve using many small planar elements with the correct delay and eliminate the diffraction devices often used by danley replacing them with slightly curved horns. This should increase output (more comps) and fidelity but basically forces the speaker to be active with a huge number of channels so wouldn't be attractive to Danley. There is also an interesting Biamp patent to infringe (j/k) using slits to tap midrange compression drivers into horns that could allow said small horns to have midranges added.
I have some thoughts on how to go beyond danley designs for output and fidelity and think a hybrid of this wavefront curvature approach and the eaw Anya hf array is the way forwards as using Hugens construction principle we can construct such a curve using many small planar elements with the correct delay and eliminate the diffraction devices often used by danley replacing them with slightly curved horns. This should increase output (more comps) and fidelity but basically forces the speaker to be active with a huge number of channels so wouldn't be attractive to Danley. There is also an interesting Biamp patent to infringe (j/k) using slits to tap midrange compression drivers into horns that could allow said small horns to have midranges added.
Yes, that is what I discussed, just above in my next-to-last paragraph.
I didn't address Paralines, at all. That is patented. Furthermore, I think DSL deserves the revenue of the Paraline (an apparent trademark) to keep their enterprise afloat.
Chris
Hi Cask05,
"While the Office reserves the right to request additional information whenever there is a question as to whether the delay is unintentional, a person filing a petition seeking reinstatement of an expired patent more than two years after the date of expiration for nonpayment of a maintenance fee is required to provide additional explanation of the circumstances surrounding the delay that establishes that the entire delay was unintentional." MPEP 2590.
Kindest regards.
M
Not necessarily, cf. 37 CFR 1.378 Acceptance of delayed payment of maintenance fee in expired patent to reinstate patent. In particular:
"While the Office reserves the right to request additional information whenever there is a question as to whether the delay is unintentional, a person filing a petition seeking reinstatement of an expired patent more than two years after the date of expiration for nonpayment of a maintenance fee is required to provide additional explanation of the circumstances surrounding the delay that establishes that the entire delay was unintentional." MPEP 2590.
Kindest regards.
M
Good to know. Note that the apparently legal sources I read stated (at that time) that effectively, after two years expiration, the party's over. You're not going to get the patent reinstated for any reason. I guess you'd have to examine the case law to see when this rather extraordinary circumstance has been used to actually reinstate a patent more than two years out of expiration due to failure to pay fees.
Note that the original patent expiration date for US6411718 occurred in 2019...so the party's over in any event for US6411718.
Chris
Note that the original patent expiration date for US6411718 occurred in 2019...so the party's over in any event for US6411718.
Chris
Hi Cask05,
Nope, no need to examine the case law, the decision is simply at the director's discretion:
"The Director may accept the payment of any maintenance fee due on a patent after expiration of the patent if, upon petition, the delay in payment of the maintenance fee is shown to the satisfaction of the Director to have been unintentional." 37 CFR 1.378(a).
The key is the unintentional, not only the failure to pay the maintenance fee must be unintentional, but also the entire delay must be unintentional. To please you, there is in fact a case law regarding this
. Rembrandt Technologies LP v. Comcast of Fla./Pa., LP, 899 F.3d 1254, 1273, 127 USPQ2d 1826, 1838 (Fed. Cir. 2018).
Kindest regard,
M
Nope, no need to examine the case law, the decision is simply at the director's discretion:
"The Director may accept the payment of any maintenance fee due on a patent after expiration of the patent if, upon petition, the delay in payment of the maintenance fee is shown to the satisfaction of the Director to have been unintentional." 37 CFR 1.378(a).
The key is the unintentional, not only the failure to pay the maintenance fee must be unintentional, but also the entire delay must be unintentional. To please you, there is in fact a case law regarding this
. Rembrandt Technologies LP v. Comcast of Fla./Pa., LP, 899 F.3d 1254, 1273, 127 USPQ2d 1826, 1838 (Fed. Cir. 2018).Kindest regard,
M
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These come up for sale periodically relatively cheap compared to most Altec products, so might be interesting to convert to MEH for outdoor parties or similar:
https://www.lansingheritage.org/images/altec/catalogs/1993-pro/1993-24.JPG
https://www.lansingheritage.org/images/altec/catalogs/1993-pro/1993-25.JPG
A patent troll... and the Eastern District of Texas courts--which are notorious for these sorts of cases (at least according to the open press)....here is in fact a case law regarding this
Wow..that's digging deep for rationale.
Chris
Nope...Patents expire and become public domain.Hi Cask05,
Nope, no need to examine the case law, the decision is simply at the director's discretion:
"The Director may accept the payment of any maintenance fee due on a patent after expiration of the patent if, upon petition, the delay in payment of the maintenance fee is shown to the satisfaction of the Director to have been unintentional." 37 CFR 1.378(a).
The key is the unintentional, not only the failure to pay the maintenance fee must be unintentional, but also the entire delay must be unintentional. To please you, there is in fact a case law regarding this
Kindest regard,
M
"
Why Do Patents Expire?
Eventually, patents do expire. While a patent will remain in force for a period of time, eventually it is considered to be no longer in effect. The patented invention then becomes freely usable by others.Patent terms, if maintained correctly, vary but generally go for up to 20 years. After the patent expires, the invention can be used by others as much as they wish. For those seeking to use the patent after its expiration, knowing this expiration date is essential. There are historical reasons for the 20-year term, but nonetheless, it remains current policy.
Patent expiration is a policy balance between rewarding research and development as well as stimulating broad societal innovation.
A patent that remains in effect for too long can restrict others from using and building on it. All technology is built on past technology. To prevent long-term slowdown and unjust enrichment, patents eventually expire.
Consumers and the public benefit from both patented inventions as well as the inventions that the patent helps spur. Patents are essentially a monopoly, which is seen as a necessary means of making research and development a worthwhile investment. A patent may also expire if the inventor or owner fails to pay the required fee on time.
Design patents do not have maintenance fees. Utility patents will require a fee at the 3.5-year mark, the 7.5-year mark, and the 11.5-year mark from issuance. The fee also must be paid during the USPTO's specific window for payment, which may change and generally is only a few months. There also is a grace period that may be granted.
The grace period allows the patent owner to pay the fee after the deadline. But if the fee is not paid during this time, the patent will expire. Under certain circumstances, such as extraordinary difficulty in paying the fee, the USPTO may allow the fee to be paid and patent retaken even after the grace period.
The patent must also be renewed annually in order to justify the continued government grant of monopoly rights. The fees increase as the patent nears the 20-year mark, therefore decreasing the incentive to keep the patent if it's not economically useful. This patent expiration policy is carefully designed to attempt to balance innovation incentives by inventors with the larger public welfare.
The exclusive economic use of the patent rewards the inventor for pushing human knowledge forward. However, if all such inventions were restricted for a long time afterward, it would significantly slow down inventions by others and thus overall social well-being.
Even though a patent provides protection for the original producer, it does not mean the competition cannot produce a similar design or method. If the idea, design, or process is similar but distinct from the original or the company has gained the rights to license the inventor's idea, it can be produced even while a patent is in effect.
The reason for putting a time limit on patents is to prevent the building of unlimited monopolies. If patents were to have no expiration date then large corporations could corner the market by securing numerous patents to push out the competition by never allowing them to create similar products or designs.
An example of a case where allowing non-expiring patents would stifle competition would be phone technology. If the patent for the creation of the telephone would be extended for a period of time as well as broadly applied, the company that gained the patent would be able to control the production of all phones. If this were to occur, it could not only stifle technological advancements but also could drive up the price, as there would be no competition to drive the price down. This is how a monopoly is created, and antitrust laws in the U.S. prevent this from occurring. Giving patents an expiration date will allow competition to keep the price competitive and allow improvements to the idea.
There are some companies that wish to hold onto the intellectual property that they use to produce products. They do not seek a patent, instead, keeping the idea from becoming publicly known by protecting it as a trade secret.
What Happens to a Patent When it Expires?
After a patent expires, the inventor loses his exclusive right to profit from the idea. Other companies can compete and produce the product or process themselves. Usually, at this point, the market will become flooded with imitations, which often drives the price of the product down and competition increases. The inventor can continue to produce the product, but buyers will often not pay the same prices when there are comparable items for much less. However, the competition can not use the inventor's name for the product.If you need help with patent expirations, you can post your legal need on UpCounsel's marketplace. UpCounsel accepts only the top 5 percent of lawyers to its site. Lawyers on UpCounsel come from law schools such as Harvard Law and Yale Law and average 14 years of legal experience, including work with or on behalf of companies like Google, Menlo Ventures, and Airbnb."
https://www.upcounsel.com/why-do-patents-expire
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Hi NBPK402,
Could you please provide legal support for these statements?
Kindest regards,
M
There are two manners in which patent expires: (i) after a time limit, cf. 35 U.S.C. 154, and (ii) due to failure to pay maintenance fees 35 U.S.C. 41(b), 37 CFR 1.362. As you have correctly observer (i) cannot be cured, but (ii) (possibly) can as demonstrated supra.
Could you please provide legal support for these statements?
Kindest regards,
M
Follow the link I posted or go to the US Patent site. "
If you need help with patent expirations, you can post your legal need on UpCounsel's marketplace. UpCounsel accepts only the top 5 percent of lawyers to its site. Lawyers on UpCounsel come from law schools such as Harvard Law and Yale Law and average 14 years of legal experience, including work with or on behalf of companies like Google, Menlo Ventures, and Airbnb."
https://www.upcounsel.com/why-do-patents-expire"
Clear as night and day lifetime patents are for xx amount of years and NOT renewable. This is to stifle Monopolies due to Patents, Trademarks and Copyrights.
If you need help with patent expirations, you can post your legal need on UpCounsel's marketplace. UpCounsel accepts only the top 5 percent of lawyers to its site. Lawyers on UpCounsel come from law schools such as Harvard Law and Yale Law and average 14 years of legal experience, including work with or on behalf of companies like Google, Menlo Ventures, and Airbnb."
https://www.upcounsel.com/why-do-patents-expire"
Clear as night and day lifetime patents are for xx amount of years and NOT renewable. This is to stifle Monopolies due to Patents, Trademarks and Copyrights.
Well, in approximate numbers for example, a 20" square = ~13543/80 = ~169 Hz, shrink it to 10" = ~338 Hz, so your call versus a larger horn/mid-bass two way cab with either passive or digital time delay.