Let's talk about 8th order bandpass alignments for a second ...
Yes, they're not considered "audiophile", but for while the Bose AM5 II series was pretty popular, and that used an 8th order BP bass module that covered the range 50 Hz to 250 Hz -3dB and was considered to be a better match for the satellites than the 6th order BP module of the previous AM5 series. And a more than 2 octave usable range is pretty decent for any BP alignment.
Designing one of these things at first looks like a big pain in the *** because of all the parameters involved (V1, V2, V3, P1, P2, P3), but I'm wondering if there might be an easier way to approach the design process, by making some of those parameters dependent on each other?
For example, going by what the internals of the AM5 II look like, maybe we can assume V1=V2, and V1+V2=V3. So, once we set a V1, V2 and V3 can be automatically calculated. Maybe even link this to driver Vas*Qts, so
V1 = a*Vas*Qts
V2 = V1
V3 = 2*V1
The ports are a little more difficult. Maybe we can make the cross-sections of the vents be multiples of driver Sd , e.g.
Sp1 = b*Sd
Sp2 = c*Sd
Sp3 = d*Sd
The lengths of the vents? Well, using the layout I'm thinking about, those will be set by the dimensions of the box. The only way to vary their resonance frequencies will be by varying their cross-sectional areas.
So, given the driver's t/s parameters, we now have only 4 variables to worry about: a, b, c and d.
In fact, it might be possible that the "ideal" values for c and d might end up being simple multiples of b, which will simplify the design even further.
I think with this it should be possible for me to put together a BOXPLAN workbook that will create a design and the corresponding Hornresp sim. Whatcha think? See any possible "holes" in my idea? Would anyone be interested in doing a test build based on the resulting sim?
Yes, they're not considered "audiophile", but for while the Bose AM5 II series was pretty popular, and that used an 8th order BP bass module that covered the range 50 Hz to 250 Hz -3dB and was considered to be a better match for the satellites than the 6th order BP module of the previous AM5 series. And a more than 2 octave usable range is pretty decent for any BP alignment.
Designing one of these things at first looks like a big pain in the *** because of all the parameters involved (V1, V2, V3, P1, P2, P3), but I'm wondering if there might be an easier way to approach the design process, by making some of those parameters dependent on each other?
For example, going by what the internals of the AM5 II look like, maybe we can assume V1=V2, and V1+V2=V3. So, once we set a V1, V2 and V3 can be automatically calculated. Maybe even link this to driver Vas*Qts, so
V1 = a*Vas*Qts
V2 = V1
V3 = 2*V1
The ports are a little more difficult. Maybe we can make the cross-sections of the vents be multiples of driver Sd , e.g.
Sp1 = b*Sd
Sp2 = c*Sd
Sp3 = d*Sd
The lengths of the vents? Well, using the layout I'm thinking about, those will be set by the dimensions of the box. The only way to vary their resonance frequencies will be by varying their cross-sectional areas.
So, given the driver's t/s parameters, we now have only 4 variables to worry about: a, b, c and d.
In fact, it might be possible that the "ideal" values for c and d might end up being simple multiples of b, which will simplify the design even further.
I think with this it should be possible for me to put together a BOXPLAN workbook that will create a design and the corresponding Hornresp sim. Whatcha think? See any possible "holes" in my idea? Would anyone be interested in doing a test build based on the resulting sim?
no - 15tbx40 https://www.bcspeakers.com/en/products/lf-driver/archive/15tbx40
thieves carrieed off 1 15tbx40, 2-15pzb40 - all never used - got m tvs, guitars, a few basses, Hurst motot for VPI, I think they took my 196cc Champion motor slated for a minibike - maybe a tub with 22-real KSN1016A
thieves carrieed off 1 15tbx40, 2-15pzb40 - all never used - got m tvs, guitars, a few basses, Hurst motot for VPI, I think they took my 196cc Champion motor slated for a minibike - maybe a tub with 22-real KSN1016A
@Brian Steele
I can offer no insight into rules of thumb, but I hope you can find some.
My 8th order tinkering has been embarrassingly crude - moving sliders in the wizard until something looked good.
Perhaps you can use this (subjectively) good design which I am yet to build and reverse engineer? If you had a handful of designs that work, it might be easier to find some constants that you seek.
I do plan to build this design. Like most things, I’m waiting for the resources (time and money) to be available in the right quantities.
I can offer no insight into rules of thumb, but I hope you can find some.
My 8th order tinkering has been embarrassingly crude - moving sliders in the wizard until something looked good.
Perhaps you can use this (subjectively) good design which I am yet to build and reverse engineer? If you had a handful of designs that work, it might be easier to find some constants that you seek.
I do plan to build this design. Like most things, I’m waiting for the resources (time and money) to be available in the right quantities.
Attachments
I SEE it's a BP8P now.
I like how you went chambers' 2>1>3 instead of chamber 3 on top of both chambers' 1 and 2 like in HR.