I don’t know that we’re looking at (typical) transmission lines much anymore? or if there even is such a thing at this point, it’s all bass reflex or cranked up
air ‘spring rate’? (hard to argue when they’re the same thing anyhow) but these models and things that Brian Steele has made in the past (boom unit, is a very nice write up, btw as is his entire highly useful website) ) do not have long rectangle shapes that would promote or suggest some of the uniqueness that occurs in offset driver entry TL. There is not enough information on the Internet, nor does there appear to be the amount of people interested in this to present anything as evidence or another way to look at ‘TL’….
Brian Steele missed this ‘science’ i suspect:
π÷9 = 0.349
this entry point promotes Helmholtz resonance. having the driver entry perfectly at this point facilitates the harmonics with double and triple the wavelength
of the fundamental, especially when the TL has 2 folds (3 sections), which causes reinforcement of the fundamental through harmonic subtraction. the reinforcement is perceived as the difference between the double and triple wavelength and thus our ear hears an additional 'ghost' fundamental, or rather a boost of that frequency. the frequencies in the box are not 'fighting' each other but rather coalescing on every node in the TL. it's like the Tacoma Narrows bridge, resonance became so strong the entire structure started waving. this is ideally what one would want, smaller-scale, in a TL
? when sim
looks nice but doesn’t match the real thing what was the point of sim?
air ‘spring rate’? (hard to argue when they’re the same thing anyhow) but these models and things that Brian Steele has made in the past (boom unit, is a very nice write up, btw as is his entire highly useful website) ) do not have long rectangle shapes that would promote or suggest some of the uniqueness that occurs in offset driver entry TL. There is not enough information on the Internet, nor does there appear to be the amount of people interested in this to present anything as evidence or another way to look at ‘TL’….
Brian Steele missed this ‘science’ i suspect:
π÷9 = 0.349
this entry point promotes Helmholtz resonance. having the driver entry perfectly at this point facilitates the harmonics with double and triple the wavelength
of the fundamental, especially when the TL has 2 folds (3 sections), which causes reinforcement of the fundamental through harmonic subtraction. the reinforcement is perceived as the difference between the double and triple wavelength and thus our ear hears an additional 'ghost' fundamental, or rather a boost of that frequency. the frequencies in the box are not 'fighting' each other but rather coalescing on every node in the TL. it's like the Tacoma Narrows bridge, resonance became so strong the entire structure started waving. this is ideally what one would want, smaller-scale, in a TL
? when sim
looks nice but doesn’t match the real thing what was the point of sim?
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where is this in ‘0.341’? its getting fuzzy? (precarious is wrong word, i dont know what is right though ?) (red,green and purple(should be brown, oops) on Generic HR model go with Martins illustration of sine wave shapes of Pmax/Vmax @ closed end)
π÷9 = 0.349
this entry point promotes Helmholtz resonance. having the driver entry perfectly at this point facilitates the harmonics with double and triple the wavelength
of the fundamental, especially when the TL has 2 folds (3 sections), which causes reinforcement of the fundamental through harmonic subtraction. the reinforcement is perceived as the difference between the double and triple wavelength and thus our ear hears an additional 'ghost' fundamental, or rather a boost of that frequency. the frequencies in the box are not 'fighting' each other but rather coalescing on every node in the TL. it's like the Tacoma Narrows bridge, resonance became so strong the entire structure started waving. this is ideally what one would want, smaller-scale, in a TL
π÷9 = 0.349
this entry point promotes Helmholtz resonance. having the driver entry perfectly at this point facilitates the harmonics with double and triple the wavelength
of the fundamental, especially when the TL has 2 folds (3 sections), which causes reinforcement of the fundamental through harmonic subtraction. the reinforcement is perceived as the difference between the double and triple wavelength and thus our ear hears an additional 'ghost' fundamental, or rather a boost of that frequency. the frequencies in the box are not 'fighting' each other but rather coalescing on every node in the TL. it's like the Tacoma Narrows bridge, resonance became so strong the entire structure started waving. this is ideally what one would want, smaller-scale, in a TL
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never fails . he opens the door to the goldmine of hidden secrets in qw resonators/soubd/physics/math/everything once you assume it is all the freq/energy concept and use it to navigate the puzzle pieces together as entries in HR.
(I can’t even explain the majority of stuff that it reveals or at least provide you an opportunity to see something that inevitably ends up being a function in other areas of physics or numerical reference mathematical value etc. that wavelength and frequency and thePmax and Vmax describe as a sequence of code that can also be found in the DNA helix and in the solar system, compass as time and units of circle descriptions from radius diameter to circumference to volume and then the expansion of the sphere?? Meanwhile the other descriptions using rectangle/hexagon /square on an existing circle are nodes to do the same exact thing in the strangest of ways as described already in architecture of the greatest possible resonator in the world(???it seems once you use it in a qw pipe??) yet discovered in the Egyptian pyramid it seems and in many ways onshift to trigonometry or radians or circumference of a circle in degrees swap to centimeters in order to expose it it we’re description of something that is however very very very real and incredibly difficult to type all at once
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The attached tables compare the results produced by all the methods and alignments proposed for the updated TL Design tool.
The first table shows non-tapered transmission line results. The second table shows the results for transmission lines having maximum taper. The same driver was used for all cases.
MK 2021 A - Alignment QL15/SBB4/BB4
MK 2021 B - Alignment QL15/QB3/SQB3
MK 2021 C - Alignment QL15/SC4 /C4
Brian,
I decided to use 1 - 5 rather than 6 - 10 for the BW range.
BW = 1 is equivalent to your BW = 6 and BW = 5 is equivalent to your BW = 10.
The first table shows non-tapered transmission line results. The second table shows the results for transmission lines having maximum taper. The same driver was used for all cases.
MK 2021 A - Alignment QL15/SBB4/BB4
MK 2021 B - Alignment QL15/QB3/SQB3
MK 2021 C - Alignment QL15/SC4 /C4
Brian,
I decided to use 1 - 5 rather than 6 - 10 for the BW range
.BW = 1 is equivalent to your BW = 6 and BW = 5 is equivalent to your BW = 10.
Attachments
Brian is the amazing one for developing the method, which as you can see from the results posted, works exceedingly well.
Interesting stuff.
I'm guessing you used my suggestion of Vb=20*Qts^3*Vas? What do the results look like if Vb=20*Qts^3.3*Vas instead?
The reason that I'm asking is that a Qts of 0.40 is sort of like the "magic number" for a 4th order box, because for a maximally-flat alignment with a driver of Qts=0.40. Fb works out to be Fs, the driver's resonance frequency. Based on the results you posted, my method (if an exponent of "3" is used), results in a TL that's larger, with an Fb that's lower than Fs.
I've got a couple more observations to make about the results you provided. Unfortunately I've got to go prepare for work. I'll do so in a followup post later this evening.
I'm guessing you used my suggestion of Vb=20*Qts^3*Vas? What do the results look like if Vb=20*Qts^3.3*Vas instead?
The reason that I'm asking is that a Qts of 0.40 is sort of like the "magic number" for a 4th order box, because for a maximally-flat alignment with a driver of Qts=0.40. Fb works out to be Fs, the driver's resonance frequency. Based on the results you posted, my method (if an exponent of "3" is used), results in a TL that's larger, with an Fb that's lower than Fs.
I've got a couple more observations to make about the results you provided. Unfortunately I've got to go prepare for work
. I'll do so in a followup post later this evening.Hi David.
I get this, a bandpass like respons, looks like a bandpass sub but is not precisely, this one has a compression chamber, when I make that bigger
it jumps into a bandpass. Nice respons, tapped horn like. Only I do not now how to get damping into the closed back chamber. Can you tell me? thanks.
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It can possibly be improved by offsetting the throat entrance to the front chamber enough to null out the first harmonic (around 400 Hz in your image).
Can I do this in hornresp? long time ago I did play, so forgot some tricks. thanks
.
Ok, finally found some time to have a look..The attached tables compare the results produced by all the methods and alignments proposed for the updated TL Design tool.
The first table shows non-tapered transmission line results. The second table shows the results for transmission lines having maximum taper. The same driver was used for all cases.
MK 2021 A - Alignment QL15/SBB4/BB4
MK 2021 B - Alignment QL15/QB3/SQB3
MK 2021 C - Alignment QL15/SC4 /C4
Brian,
I decided to use 1 - 5 rather than 6 - 10 for the BW range
BW = 1 is equivalent to your BW = 6 and BW = 5 is equivalent to your BW = 10.
Starting with the driver parameters:
Fs=28 Hz
Vas=71.03 litres
Qts=0.40
Using the "optimum box" equations, we get
Vb=20*Qts^3.3*Vas=20*).4^3.3*71.03=69.1 litres
Fb=(Vas/Vb)^0.31*Fs=(71.03/69)^0.31*28=28.2 Hz
Using my suggested equations (which admittedly are based on a few sims), we get
Vb=20*Qts^3*Vas=20*).4^3.3*71.03=90.9 litres
Fb=(Vas/Vb)^0.31*Fs=(71.03/69)^0.31*28=25.9 Hz
The "BS2022" method in your table. with a BW setting of 1 has Vb at 87.382 litres, or 96% of the value provided by my suggested equations.
You didn't include Fb in your table, but plugging the figures into a Hornresp sim results in an Fb of 26.4 Hz, 2% over the value provided by my suggested equations.
I think that's close enough
The "BS2022" method in your table. with a BW setting of 5 has Vb at 87.382 litres, or 96% of the value provided by my suggested equations. so no change there. Plugging the figures into a Hornresp sim however results in an Fb of 27.2 Hz, 5% over the value provided by my suggested equations. Is a 5% difference Ok? I'm not sure, but I remind myself that this is just for a "suggested TL", not an "optimized TL"...
I noted also that the volume of the TL predicted by my suggested equation for Vb is noticeably smaller than that predicted by MK2006, but also noticeably larger than predicted by MK2021. I suspect that the predicted volume would be a lot closer to the MK202 figures if Vb=20*Qts^3.3*Vas was used instead, and maybe we should use that going forward.
Interesting results for the straight TLs.
The TL looks Ok in image 1 (BS022), oversized in image 2 (MK2006), undersized in image 3 (MK2021A), and Ok in images 4 and 5 (MK2021B and MK2021C).
The results suggest that the best TL for this driver lies somewhere between 58 and 87 litres. If the "optimum box" equation to calculate Vb in my method, that spread would be between 58 and 69 litres (another hint that perhaps using Vb=20*Qts^3.3*Vas for my method might produce better results).
The size predicted by MK2006 (120.7 litres) seems way too large. Perhaps only usable if the TL is going to be stuffed.
I suggest rechecking the calculations being used for MK2021A, as the result seems grossly undersized.