MJK said:
I believe I may have had run-ins with the same individual
on the same forum (more of a list-serv) actually. I haven't posted to that list in years.Glad you took no offense.
BAM,
If you're considering patenting an enclosure design realize this...
pretty much anything that can possibly be done with enclosures has already been done.
If you're considering patenting an enclosure design realize this...
pretty much anything that can possibly be done with enclosures has already been done.
BassAwdy:
Nothing gets done until somebody decides to do it. If there is an advantage to BAM's enclosure, he should patent it.
Hey-it might not be usable for every enclosure in all situations. But when you consider all the variations of pro/hifi sound, and all the applications, inventing an enclosure with real advantages in even one application might well result in money coming in.
Also, bear in mind that BAM is an engineering student who has been posting on enclosures since he was in high school.
Getting a patent on an enclosure type with advantages in certain applications will sure look nice on job applications.
And who is to say he won't receive an offer from some large company who wants to use it, because it gives an advantage over the competition? Or might just lead to a job offer from the company interested in the patent?
I think BAM should go for it.
Nothing gets done until somebody decides to do it. If there is an advantage to BAM's enclosure, he should patent it.
Hey-it might not be usable for every enclosure in all situations. But when you consider all the variations of pro/hifi sound, and all the applications, inventing an enclosure with real advantages in even one application might well result in money coming in.
Also, bear in mind that BAM is an engineering student who has been posting on enclosures since he was in high school.
Getting a patent on an enclosure type with advantages in certain applications will sure look nice on job applications.
And who is to say he won't receive an offer from some large company who wants to use it, because it gives an advantage over the competition? Or might just lead to a job offer from the company interested in the patent?
I think BAM should go for it.
BAM
If you go the patent way, pay attention to how it's written, not to leave loopholes that could aloow others to circumvent your patent...
If you go the patent way, pay attention to how it's written, not to leave loopholes that could aloow others to circumvent your patent...
Hey... I didnt say his idea had already been done, just that most anything that can be done with enclosures has already been thought of. If he has something that is truely unique, great.
Another aspect of it is what it will take to get a patent. Money money money.
Another aspect of it is what it will take to get a patent. Money money money.
If you want to patent something, you really have to file it within a year of it's initial public anoucement.
yeah.... but bam hasnt made any public announcements. He just said he has an idea that has something to do with a high order BR with 3 chambers... That could mean many things
Yeah, here are some of the advantages to the enclosure design I'm proposing, if my suspicions and assumptions based on experience with other enclosures is correct.
1. Extremely deep bass potential without unloading of the cone at Fs
2. Output is boosted (won't say how) if the designer wants it to be, though this limits the bandwidth over which the ports can continue to supply the extra low bass output.
3. No midrange gets carried out of the vent
4. Possible series-tuning effects can extend output even lower, but at a much reduced level
5. People who like single-driver loudspeakers may now get good bass extension if they want something that will be good over a wide range
6. If I can get a patent, then the design is something nobody has ever done before.
Disadvantages to my enclosure design:
1. The enclosure relies mainly on resonances to generate output so it will tend to be "boomier" and have more overhang than most single- and dual-chamber bass reflex boxes
2. The design itself is as of yet unproven. Prototype is coming this fall, and uses a Tang Band W4-1052SA driver to demonstrate its usefulness with a single-driver design.
3, Large size, though this is not so much of a problem since there is stuff going on inside that will generate low frequency output like a very deep-tuned EBS, but will still load the woofer at its Fs.
1. Extremely deep bass potential without unloading of the cone at Fs
2. Output is boosted (won't say how) if the designer wants it to be, though this limits the bandwidth over which the ports can continue to supply the extra low bass output.
3. No midrange gets carried out of the vent
4. Possible series-tuning effects can extend output even lower, but at a much reduced level
5. People who like single-driver loudspeakers may now get good bass extension if they want something that will be good over a wide range
6. If I can get a patent, then the design is something nobody has ever done before.
Disadvantages to my enclosure design:
1. The enclosure relies mainly on resonances to generate output so it will tend to be "boomier" and have more overhang than most single- and dual-chamber bass reflex boxes
2. The design itself is as of yet unproven. Prototype is coming this fall, and uses a Tang Band W4-1052SA driver to demonstrate its usefulness with a single-driver design.
3, Large size, though this is not so much of a problem since there is stuff going on inside that will generate low frequency output like a very deep-tuned EBS, but will still load the woofer at its Fs.
BAM said:
Depends what you mean by "large size".
In loudspeaker enclosures, size is pretty much determined by bass output versus Vas / Vb ratio.
As an example, in a classic tuned reflex, where Qts = 0.38, Vas = Vb, and box is tuned to Fs, Fs = F3. I kind of use that as a guide to judge loudspeaker enclosures.
If your speaker has an Fs = 40 Hz, and when you put it in a box equal to it's Vas, the F3 = 80 Hz, then I would say that is a very large box for the output you get from it.
If the same speaker, (Fs = 40 Hz), is put into a unique enclosure with a total volume equal to it's Vas, and produced an F3 of 40 Hz, then I would say the enclosure-whatever it is- is not large for it's bass output. It's about equal to a ported design's.
Of course, lower rate of bass rolloff is desirable, so a box with a somewhat higher F3 but a lower rate of bass rolloff could be considered about equal output to a ported box's. In other words, if we put that same speaker, Fs = 40 Hz, into a unique enclosure which requires 1.25 Vas to produce an F3 of 40 Hz, but the rolloff rate is second or third order instead fourth, then I would say that unique enclosure requires a "box size" roughly equal to a ported design's, all things taken into account.
I just mean this as a general guide. You can weigh the factors for yourself, of course, as well as anyone who wishes to use the enclosure after you patent it.
I just wanted to give you some kind of baseline to judge "box size".
Next Chamber Coupling Theory
I think I've figured out how "series tuning" works. I call my theory the "Next Chamber Coupling Theory".
Consider a woofer, loaded into an air chamber. That chamber also has a bass reflex port which empties into another chamber which is vented to the outside. The two chambers are not necessarily the same size, and the two ports are not necessarily the same length or size. My theory is this: When the vent that connects the chambers is resonating, the next chamber is functioning as a 4th-order acoustic bandpass filter, tuned to a frequency determined by the vent leading to the outside, or the next chamber in series. If it has a narrow band that is centered at the tuning frequency of the first chamber (Fb sub 1), it will reinforce the output of the first port, which is resonating. But below the tuning frequency of the first chamber, the vent is unloaded, so the woofer "sees" the two chambers as one volume. I imagine that at any frequency that the first chamber is not resonantly loaded by the vent, the woofer will "see" the two chambers as one. Anyway, when the woofer is seeing the two chambers as one volume, the vent in the next chamber (hence the name of my theory) determines the resonant loading frequency (Fb sub 2) of that entire volume. So, three tuning frequencies (Fb sub 1-thru-3) are calculated. The first is the vent in the first chamber. The second is the vent in the second chamber. Then the third Fb is calculated with the vent tuning the two chambers if they are summed into one. Does it seem reasonable that when the vent between the two chambers is unloaded, the woofer "sees" the two chambers as one total volume, tuned by the port that radiates to the outside (assuming the port is not extremely restrictive of flow)? And does it seem reasonable that the second chamber acts as a 4th-order acoustic bandpass at frequencies equal to or above the tuning frequency of the vent that connects the two chambers?
I think I've figured out how "series tuning" works. I call my theory the "Next Chamber Coupling Theory".
Consider a woofer, loaded into an air chamber. That chamber also has a bass reflex port which empties into another chamber which is vented to the outside. The two chambers are not necessarily the same size, and the two ports are not necessarily the same length or size. My theory is this: When the vent that connects the chambers is resonating, the next chamber is functioning as a 4th-order acoustic bandpass filter, tuned to a frequency determined by the vent leading to the outside, or the next chamber in series. If it has a narrow band that is centered at the tuning frequency of the first chamber (Fb sub 1), it will reinforce the output of the first port, which is resonating. But below the tuning frequency of the first chamber, the vent is unloaded, so the woofer "sees" the two chambers as one volume. I imagine that at any frequency that the first chamber is not resonantly loaded by the vent, the woofer will "see" the two chambers as one. Anyway, when the woofer is seeing the two chambers as one volume, the vent in the next chamber (hence the name of my theory) determines the resonant loading frequency (Fb sub 2) of that entire volume. So, three tuning frequencies (Fb sub 1-thru-3) are calculated. The first is the vent in the first chamber. The second is the vent in the second chamber. Then the third Fb is calculated with the vent tuning the two chambers if they are summed into one. Does it seem reasonable that when the vent between the two chambers is unloaded, the woofer "sees" the two chambers as one total volume, tuned by the port that radiates to the outside (assuming the port is not extremely restrictive of flow)? And does it seem reasonable that the second chamber acts as a 4th-order acoustic bandpass at frequencies equal to or above the tuning frequency of the vent that connects the two chambers?
Re: Next Chamber Coupling Theory
Seems to me for what you are saying to be true, the second chamber has to be at laest four times the volume of the first chamber. Ohterwise, there will be significant interaction between the two.
And if you are banking on there being huge differential between the tuning of the second chamber alone and the combined tuning of the first and second chambers taken together, that would be a mistake. The same size tube inserted into an enclosure of 2 cubic feet would not tune much different if inserted into an enclosure of 2.5 cubic feet-a 25% difference.
And that is what the difference would be be if the second chamber is joined to a top chamber only 25% it's size-a 25% percent volume difference.
In this thread, people who have tried the double chamber idea have said that if the tuning of the top and bottom chamber is not more than an octave apart, all sorts of interferences occur and the response suffers.
BAM said:
Seems to me for what you are saying to be true, the second chamber has to be at laest four times the volume of the first chamber. Ohterwise, there will be significant interaction between the two.
And if you are banking on there being huge differential between the tuning of the second chamber alone and the combined tuning of the first and second chambers taken together, that would be a mistake. The same size tube inserted into an enclosure of 2 cubic feet would not tune much different if inserted into an enclosure of 2.5 cubic feet-a 25% difference.
And that is what the difference would be be if the second chamber is joined to a top chamber only 25% it's size-a 25% percent volume difference.
In this thread, people who have tried the double chamber idea have said that if the tuning of the top and bottom chamber is not more than an octave apart, all sorts of interferences occur and the response suffers.
BAM said:
I think this would play a major role.
Deep & loud bass is beautiful only when it's under control.
In comparison, vented enclosure is already boomier then closed, not to mention open baffle or horn. (Of course I mean good designs/well built for all of them)
Band pass mulitple vented enclosure is indeed worse then simple bass reflex box.
Among all of the enclosure types I've listened to, in the case of vented design, it's good only when mated with big, expensive, professional underhung driver.
The double bass reflex system will have as many resonances as there are lumped masses, for example the driver's cone/coil plus the number of ports. None of the system resonances will occur at the individual resonances, like the driver's fs or any of the individual f's of the chambers and ports. This is all simple vibration theory and the equations can be derived to predict the different resonances (modes) of this simple multi-degree of freedom system. You don't need to guess based on geometry and you should be able to come up with a form of alignment to get whatever optimized responses are possible.
If you can derive the equations for a ported box from the basic equivalent mechanical system and equivalent circuit models then exteding this to a double bass reflex design should be the next step. If you cannot derive the equations for a ported box by following the Thiele/Small papers then that might be a good starting point to learning about the double bass reflex enclosure. If you don't do the math, then you are just winging it and the results will be somewhat hit or miss. A little math and theory trumps a lot of talking every time. If you don't do the math, then a patent will be somewhat difficult to obtain and enforce.
If you can derive the equations for a ported box from the basic equivalent mechanical system and equivalent circuit models then exteding this to a double bass reflex design should be the next step. If you cannot derive the equations for a ported box by following the Thiele/Small papers then that might be a good starting point to learning about the double bass reflex enclosure. If you don't do the math, then you are just winging it and the results will be somewhat hit or miss. A little math and theory trumps a lot of talking every time. If you don't do the math, then a patent will be somewhat difficult to obtain and enforce.
Double-length ports in same box
Hi guys
This is a slightly different idea. How would you go about modelling a box with two ports of different length in the same volume (i.e. not a dual chamber box- see picture below)? This would be to extend the lower bass of a driver with a very low Q. Any ideas? Can one use UniBox (as per RJ's suggestion)?
Thanks,
Deon
Hi guys
This is a slightly different idea. How would you go about modelling a box with two ports of different length in the same volume (i.e. not a dual chamber box- see picture below)? This would be to extend the lower bass of a driver with a very low Q. Any ideas? Can one use UniBox (as per RJ's suggestion)?
Thanks,
Deon
Attachments
Greets!
Don't know of a program that will model them per se, but I visualize them as a single vent with an angled exit, ergo the pipes will have a single broadband resonance (low Q). I mean if you couple enough of them together with a 1/4WL difference between them you have in essence a BLH of 'x' BW depending on how many pipes are used.
Anyway, the angled pipe is a good way to have a well damped vent without flares or 'stuffing a sock in it', but the woodworking expertise required keeps most folks from using it.
GM
Don't know of a program that will model them per se, but I visualize them as a single vent with an angled exit, ergo the pipes will have a single broadband resonance (low Q). I mean if you couple enough of them together with a 1/4WL difference between them you have in essence a BLH of 'x' BW depending on how many pipes are used.
Anyway, the angled pipe is a good way to have a well damped vent without flares or 'stuffing a sock in it', but the woodworking expertise required keeps most folks from using it.
GM
I am beginning to wonder if a patent is quite the right thing. I could patent it and claim to have an enclosure that can get deep bass from a small driver while still controlling the driver's resonance, but then it only accomplishes about the same thing as a built-in subwoofer, which would probably get better results unless it was extremely poorly designed. Instead, I am thinking of just making a web page to discuss the whole thing so that no one else can claim to have "invented" what I think I've invented and then try to patent it. I don't really have a means to profit all that well from this, so if I were to patent it, I probably would just wind up abandoning it for more tried-and-true enclosure loading technologies. I don't need exclusive rights to profit from this, I just thought it would look great on a resume submitted to loudspeaker companies.
Is there a book or AES paper that covers the interaction between the chambers of a series-tuned bass reflex enclosure? There would have to be some insane interactions in the case of the Weems/Augspurger (dual chamber, each ported to the outside and the two chambers connected by a port) double bass reflex.
I am thinking I'll just build a box and do an impedance sweep with the help of a speaker-building friend of mine to see where the tuning frequencies are.
Is there a book or AES paper that covers the interaction between the chambers of a series-tuned bass reflex enclosure? There would have to be some insane interactions in the case of the Weems/Augspurger (dual chamber, each ported to the outside and the two chambers connected by a port) double bass reflex.
I am thinking I'll just build a box and do an impedance sweep with the help of a speaker-building friend of mine to see where the tuning frequencies are.
BassAwdyO said:
I'm just curious what the costs are.
Think I'll start a thread in the Everything Else section.
If I remeber correctly the filing fee alone is somewhere near $700. You will, however, need to get a patent lawyer to write it up for you. Less you happen to be a patent lawyer yourself, or want a patent that probably wont do anything for you(can easily be worked around and used by someone else legally).
I started a thread on patents a while ago...
I think it was labeled "how to patent your basstastic ideas" in the subwoofer forum
I started a thread on patents a while ago...
I think it was labeled "how to patent your basstastic ideas" in the subwoofer forum
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