I'd love to try one, just to see what the design process is like and how accurate the sims are.
My concern is that the HornResp sim doesn't include the impact of losses, and there's also the question of port lengths being affected by their actual position in the box, something that's not addressed in Hornresp.
It's Ok if you design for A and get something approximately like A, which is what happens when most people use Hornresp for designing bass horns. It's another thing to design for A and get B, something totally different, due to an "accumulation of errors" caused by what I indicated above.
There's also the question of design methodology, i.e. how would be your start point for designing such a thing? e.g. given a particular driver, how would you go about designing the best 8th order BP for it? How does one choose a driver for such an alignment anyway?
My concern is that the HornResp sim doesn't include the impact of losses, and there's also the question of port lengths being affected by their actual position in the box, something that's not addressed in Hornresp.
It's Ok if you design for A and get something approximately like A, which is what happens when most people use Hornresp for designing bass horns. It's another thing to design for A and get B, something totally different, due to an "accumulation of errors" caused by what I indicated above.
There's also the question of design methodology, i.e. how would be your start point for designing such a thing? e.g. given a particular driver, how would you go about designing the best 8th order BP for it? How does one choose a driver for such an alignment anyway?
For what it's worth
I have toyed around with the idea of 8th order alignments and i came up with a few good sims, and possible foldings and layouts .... I mentioned it over at the Mass Loaded Transflex / Karlflex discussion a few times but never got around to building one of these 8th order cabs ...
As far as drivers are concerned, Low VAS , Mid Q drivers with strong motors seem to work well for this .... Beyma 15p1200ND/n , B&C 18TBW100 , Eminence Definimax 4012 , and dual Alpine SWE-10S4 (no longer available) all simulated very well in this type of cabinet .. .
Efficiency and output is decent for a smallish box however this is not the design of choice if you are shooting for extreme bass extension or ultimate cone control ..... This design is all about efficiency in a cabinet that would be smaller than a FLH for a given driver .... According to simulations this design looks like it competes well in terms of size/performance when compared to other popular DIY configurations such as Tapped Horns, but real world performance has yet to be tested because nobody has built one yet..
I have toyed around with the idea of 8th order alignments and i came up with a few good sims, and possible foldings and layouts .... I mentioned it over at the Mass Loaded Transflex / Karlflex discussion a few times but never got around to building one of these 8th order cabs ...
As far as drivers are concerned, Low VAS , Mid Q drivers with strong motors seem to work well for this .... Beyma 15p1200ND/n , B&C 18TBW100 , Eminence Definimax 4012 , and dual Alpine SWE-10S4 (no longer available) all simulated very well in this type of cabinet .. .
Efficiency and output is decent for a smallish box however this is not the design of choice if you are shooting for extreme bass extension or ultimate cone control ..... This design is all about efficiency in a cabinet that would be smaller than a FLH for a given driver .... According to simulations this design looks like it competes well in terms of size/performance when compared to other popular DIY configurations such as Tapped Horns, but real world performance has yet to be tested because nobody has built one yet..
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Hi Brian,
As indicated some time ago in my Post #5472 on the Hornresp thread, the predictions should hopefully be reasonably accurate at bass frequencies. We won't know for sure though, until some brave soul decides to have a go at building and testing one
.For some reason, I gained the impression that these alignments were being used for car sub-woofer designs, but perhaps I was mistaken in thinking this. I am starting to wonder why the feature was requested at all, if no one is building these speakers. I hope I didn't spend time developing new simulation models that nobody intends using
.Kind regards,
David
Hmm, I thought it was requested to sim K15s except with a basic vent cutout, then use the cutout's area to reshape it to an expo, hypex/whatever Karlson slot without having to resort to using AkAbak or at least getting 99% of it into AkAbak to fine tune the K-slot.
It can also be used to extend a TH's [6th order] usable BW, so between the two it seems a worthy upgrade if folks can figure out how to input it and use the LW to tweak it.
GM
It can also be used to extend a TH's [6th order] usable BW, so between the two it seems a worthy upgrade if folks can figure out how to input it and use the LW to tweak it.
GM
it should do a good job of catching K15's characteristics where it counts - I'm not feeling well enough to give a go - it should be great to make general predictions to avoid wasting wood with new K's
K15 by Carl's estimation
vf = 2.3 cu ft
vb = 4.0 cu ft (before driver displacement)
sb = 32 sq inches
sf = 222 sq inches
The rear shelf creates a port area of 52.5 sq inches with the back of the cabinet.
The front shelf creates an area of 73.5 sq inches with the front panel.
K15 by Carl's estimation
vf = 2.3 cu ft
vb = 4.0 cu ft (before driver displacement)
sb = 32 sq inches
sf = 222 sq inches
The rear shelf creates a port area of 52.5 sq inches with the back of the cabinet.
The front shelf creates an area of 73.5 sq inches with the front panel.
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Hi,
I'm still unconvinced. Low bass interacts will the drivers 2nd order
rolloff and gives a maximum of an acoustic 4th order rolloff. There
is no rolloff for the front loading so the front maximum is 2nd order.
i.e the maximum acoustic is 6th order, vented, TL etc.
If you can arrange the front to be 4th order, the same could be used
at the rear for an overall 10th order, AFAIK it simply doesn't exist.
There is no evidence at all Karlson is 8th order.
The concepts to me seem to be being inaccurately misused.
rgds, sreten.
I'm still unconvinced. Low bass interacts will the drivers 2nd order
rolloff and gives a maximum of an acoustic 4th order rolloff. There
is no rolloff for the front loading so the front maximum is 2nd order.
i.e the maximum acoustic is 6th order, vented, TL etc.
If you can arrange the front to be 4th order, the same could be used
at the rear for an overall 10th order, AFAIK it simply doesn't exist.
There is no evidence at all Karlson is 8th order.
The concepts to me seem to be being inaccurately misused.
rgds, sreten.
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The K15 is a [4] resonant cavity box [defined as polyresonant by PWK], ergo 8th order, so we'll have to agree to disagree: http://home.planet.nl/~ulfman/images/klipsch.jpg
The various other Karlsons are 4th or 6th order.
GM
The various other Karlsons are 4th or 6th order.
GM
Hi,
The K15 4 cavity box does not indicate any sort of 8th order response,
in anyones imagination given the information that you have provided.
I don't want evidence, I want the proper theory for 4th order front.
rgds, sreten.
The graph shown indicates its at best 4th order high pass,
with no low pass, with some 2nd order mid notches.
Its interesting the measurement notes that the claimed
response is +/- 2dB 20Hz to 20KHz, hardly 8th order.
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I am starting to wonder why the feature was requested at all, if no one is building these speakers. I hope I didn't spend time developing new simulation models that nobody intends using
Oh, I don't want to discourage anyone from actually trying an 8th order system. Just be prepared for a bit of cutting and trimming to get the tuning right, if it's a BP alignment.
Here's an example - a 4th order BP (the lowest order possible) as sim'd in HornResp vs. actual measurements. I expect that as the order increases, the "accumulation of errors" will also increase.
Attachments
I don't think deletion of K15's rear shelf as its placed would have much impact upon its frequency response - IIRC that gap is ~2.5" from shelf edge to rear panel for ~52sq.in area (not including cleats) - the front shelf seems to deflect
these ~ground plane dips on this coupler would not look as deep if it were rocked forwards so the baffle is perpendicular to the ground
there was no rear shelf in this box - vents were two 4.5" holes IIRC - despite the meek FR, it was punchy with that Eminence 18
these ~ground plane dips on this coupler would not look as deep if it were rocked forwards so the baffle is perpendicular to the ground
there was no rear shelf in this box - vents were two 4.5" holes IIRC - despite the meek FR, it was punchy with that Eminence 18
An externally hosted image should be here but it was not working when we last tested it.
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Not really sure what you're wanting here, but if it's the electrical circuit equivalent or some mathematical explanation I can't provide it or even point you to a web page or JAES paper.
Hopefully we can agree that the driver's front/rear chamber [if sealed] is a 4th order BP and it's my understanding that every additional resonant chamber coupled to it adds another 2nd order to it, ergo the two upper chambers that couple to the two bottom chambers increase it to 8th order.
Anyway, David apparently knows the math good enough to mod HR to sim one, so hoping he'll chime in and either confirm it's an 8th order or ??? and maybe understand/answer your Qs.
Yeah, the marketing hype was so ridiculous, misleading that it became the leading audio pariah until fairly recently and even now is only a viable 'full-range' speaker to a very few. Personally, I think it's just a good ~three octave BP while some others find it acceptable to ~four octaves.
Note that the 20-20 kHz was presumably based on the K15 being loaded with an Altec 604 duplex or similar co-ax or tri-ax.
GM
it could be fun doing a simple so called 8th order ABC The ABC 8th Order Bandpass | Decibelcar.com the Car Audio Knowledgebase
as drawn it looks like a combination of parallel and series 6th order bp - I've seen the ABC also drawn as a standard Weems style DCR and its not intuitive to me what the one below would do - a sim would be helpful to see if its workable with the 2:1 chamber ratio and tunings
as drawn it looks like a combination of parallel and series 6th order bp - I've seen the ABC also drawn as a standard Weems style DCR and its not intuitive to me what the one below would do - a sim would be helpful to see if its workable with the 2:1 chamber ratio and tunings
An externally hosted image should be here but it was not working when we last tested it.
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Hi,
Not really, A sealed box is 2nd order and a front and rear sealed is useless.
4th order BP is front vented or TL, 6th order is both vented or TL, how you
get beyond that acoustic limitation physically is beyond my understanding.
The ABC design is not 8th order, and its operating description is very poor.
rgds, sreten.
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Sorry, my bad, I thought you knew enough about basic BP alignments to know I meant just the rear chamber is sealed in a 4th order BP.
A 4th order BP has a vented front chamber and a sealed rear chamber. A 6th order BP either has a vent in both chambers or one between the two, which is sometimes referred to as a quasi-6th order BP and if I'm right, then 8th order adds a coupling chamber to it as per the K15.
What acoustic limitation?
GM
A 4th order BP has a vented front chamber and a sealed rear chamber. A 6th order BP either has a vent in both chambers or one between the two, which is sometimes referred to as a quasi-6th order BP and if I'm right, then 8th order adds a coupling chamber to it as per the K15.
What acoustic limitation?
GM
To get the order of the loudspeaker box, simply add the orders of the low-pass and the high-pass filters of the box.
- Second-order box is a sealed box, it has only high-pass filter which is 2nd-order (12dB/octave) and none low-pass filter.
- Fourth-order box is either conventional bass-reflex box with only high-pass filter which is 4th-order (24dB/octave) and none low-pass filter, or band-pass box with sealed back and vented front chamber - which makes 2nd-order high-pass filter (12dB/octave) plus 2nd-order low-pass filter (12dB/octave).
-Sixth-order box has two vented chambers, with two variants - serial and parallel. Both have 4th-order high-pass filter (24dB/octave) plus 2nd-order low-pass filter (12dB/octave).
- Eighth-order box has three vented chambers, the third one couples previous two together (or only the front one), to make 4th-order high-pass filter (24dB/octave) plus 4th-order low-pass filter (24dB/octave). Bose once had that kind of subwoofer in one of the many incarnations of his infamous Acoustimass range of subwoofers.
ABC design with only two vented chamber connected with a vent between looks to me as a 6th-order box (with an unnecessary complication). Will anyone skilled in AkAbak shed some light on this, please?
- Second-order box is a sealed box, it has only high-pass filter which is 2nd-order (12dB/octave) and none low-pass filter.
- Fourth-order box is either conventional bass-reflex box with only high-pass filter which is 4th-order (24dB/octave) and none low-pass filter, or band-pass box with sealed back and vented front chamber - which makes 2nd-order high-pass filter (12dB/octave) plus 2nd-order low-pass filter (12dB/octave).
-Sixth-order box has two vented chambers, with two variants - serial and parallel. Both have 4th-order high-pass filter (24dB/octave) plus 2nd-order low-pass filter (12dB/octave).
- Eighth-order box has three vented chambers, the third one couples previous two together (or only the front one), to make 4th-order high-pass filter (24dB/octave) plus 4th-order low-pass filter (24dB/octave). Bose once had that kind of subwoofer in one of the many incarnations of his infamous Acoustimass range of subwoofers.
ABC design with only two vented chamber connected with a vent between looks to me as a 6th-order box (with an unnecessary complication). Will anyone skilled in AkAbak shed some light on this, please?
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