@ freddi
I simmed it in WinISD v.07.0.900 as described in the The ABC 8th Order Bandpass | Decibelcar.com the Car Audio Knowledgebase link. It doesn't pan out with those identical port lengths, & that tuning ?
If i altered the smaller Vol's tuning, & port length, then it did !
85L @ 30Hz & 42.5L @ 42.5Hz
3 x ports @ 140mm D x 500mm L (INT)
I simmed it in WinISD v.07.0.900 as described in the The ABC 8th Order Bandpass | Decibelcar.com the Car Audio Knowledgebase link. It doesn't pan out with those identical port lengths, & that tuning ?
If i altered the smaller Vol's tuning, & port length, then it did !
85L @ 30Hz & 42.5L @ 42.5Hz
3 x ports @ 140mm D x 500mm L (INT)
Attachments
yes on the lowpass - here's a recently built BP4 I have - trace in red
An externally hosted image should be here but it was not working when we last tested it.
Hi,
I still maintain there is no such thing as 8th order. If you can
add something to the front to make it 4th order, the same
could be added to the back for 10th order, they don't exist.
Multiple coupling chambers don't change the physics,
you can't make a 4th order front or 6th order rear.
rgds, sreten.
I still maintain there is no such thing as 8th order. If you can
add something to the front to make it 4th order, the same
could be added to the back for 10th order, they don't exist.
Multiple coupling chambers don't change the physics,
you can't make a 4th order front or 6th order rear.
rgds, sreten.
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one could add an additional vented chamber in front of a normal 6th order series vented or parallel vented bandpass box - advantages
= I don't know - a simulator would really help
Bose for years has used a triple chamber http://www.whatsinside.info/bose-acoustimass-5-series-ii-transparent/
= I don't know - a simulator would really help
Bose for years has used a triple chamber http://www.whatsinside.info/bose-acoustimass-5-series-ii-transparent/
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I want to see some simulations - - a choke and cap and certainly electronic crossover rolloff would add an order or two better than an extra chamber in the two arrangements above. Are there any "8th" order BP arrangements with some advantage in the passband?
"Isaac" many years ago had a prototype calculator which was supposed to deal with one 8th order type
http://users.on.net/~isaacmcn/audio/subsim/newsubsim.htm
"Isaac" many years ago had a prototype calculator which was supposed to deal with one 8th order type
http://users.on.net/~isaacmcn/audio/subsim/newsubsim.htm
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@ Sonce
Hi, yeah good catch ! I was also simming a BR round about the same time, so i expect i didn't properly check the image i uploaded. Anyway you're correct about the lack of LP on the sim. Just redid it with the same driver Eminence Kilomax 18, & it's the same. Don't know why ? Maybe someone else could try & see what's happening
Hi, yeah good catch ! I was also simming a BR round about the same time, so i expect i didn't properly check the image i uploaded. Anyway you're correct about the lack of LP on the sim. Just redid it with the same driver Eminence Kilomax 18, & it's the same. Don't know why ? Maybe someone else could try & see what's happening
A little more detail
I have tried simulating the design posted in post #17 using Akabak but i did not have much luck getting it to work any better than a parallel tuned 6th order bandpass ...
The designs in post #7 can be seen as a Tapped Pipe or Transflex which many folks consider 6th order (like a Tapped Horn is according to some) , but modified with the additional resonant pipe tuned to place it roughly around the third pipe harmonic (or just below depending on the driver) and the additional resonant pipe section adds 2 orders giving us 8th order (just as a chamber&port set would) ...... That was my reasoning behind calling these 8th order... But perhaps other folks might say that this is just a 6th order with an additional resonance in the middle ..
The designs posted in post #7 were simmed in Hornresp using a few unorthodox arrangements of VRC and VTC , and they are the quarter wave (Eigenmode) equivalents of the Helmholtz 8th order in post #25 (Freddi's second sketch that is labeled "Eighth Order Triple Reflex") ...
To explain the Helmholtz version we can use the second sketch in post #25 as a reference: The lower left chamber is of course a sizable chamber with a long port which creates the fundamental resonance. The lower right chamber is the smaller one with shorter port and defines the box's upper response cutoff .... The upper chamber is tuned somewhere in between the other two resonances , and also provides additional loading on the 1st chamber shifting it's resonance downward ...
I have tinkered around a lot with this sort of design in sim and that (the above) is the only way i can seem to get these to work well, so as an example the three resonances could be spaced as 40hz , 90hz and 140hz ..... You can clearly see that three-point pattern in some 8th order sims when they are dialed in well, a cutoff on the bottom and top (of course) with sometimes a bit of a bump in the middle corresponding with the middle resonance, and accompanied by three impedance minimums within the working range, and four noticeable impedance peaks with the first peak located below FB as usual , two in the middle (on each side of the mid resonance), and the last one around/above the top resonance (or the fifth pipe harmonic in the case of the Transflex version of the 8th order)...
With the right driver (which is key) you can really squeeze a lot of decibels out without too much input power(good efficiency), using a cabinet size that is not too outlandish in my opinion, at least that has been my experience with the Eigenmode versions of the 8th order simulations .....
Might be an adventurous option to try out if you have one of those Beyma 15s laying around or a Definimax12 and want to do something unique and experimental Be the first guy in the world to build and own one! Could make a good PA sub in a portable package as long as you aren't needing to get below the 35-40hz range.
I have tried simulating the design posted in post #17 using Akabak but i did not have much luck getting it to work any better than a parallel tuned 6th order bandpass ...
The designs in post #7 can be seen as a Tapped Pipe or Transflex which many folks consider 6th order (like a Tapped Horn is according to some) , but modified with the additional resonant pipe tuned to place it roughly around the third pipe harmonic (or just below depending on the driver) and the additional resonant pipe section adds 2 orders giving us 8th order (just as a chamber&port set would) ...... That was my reasoning behind calling these 8th order... But perhaps other folks might say that this is just a 6th order with an additional resonance in the middle ..
The designs posted in post #7 were simmed in Hornresp using a few unorthodox arrangements of VRC and VTC , and they are the quarter wave (Eigenmode) equivalents of the Helmholtz 8th order in post #25 (Freddi's second sketch that is labeled "Eighth Order Triple Reflex") ...
To explain the Helmholtz version we can use the second sketch in post #25 as a reference: The lower left chamber is of course a sizable chamber with a long port which creates the fundamental resonance. The lower right chamber is the smaller one with shorter port and defines the box's upper response cutoff .... The upper chamber is tuned somewhere in between the other two resonances , and also provides additional loading on the 1st chamber shifting it's resonance downward ...
I have tinkered around a lot with this sort of design in sim and that (the above) is the only way i can seem to get these to work well, so as an example the three resonances could be spaced as 40hz , 90hz and 140hz ..... You can clearly see that three-point pattern in some 8th order sims when they are dialed in well, a cutoff on the bottom and top (of course) with sometimes a bit of a bump in the middle corresponding with the middle resonance, and accompanied by three impedance minimums within the working range, and four noticeable impedance peaks with the first peak located below FB as usual , two in the middle (on each side of the mid resonance), and the last one around/above the top resonance (or the fifth pipe harmonic in the case of the Transflex version of the 8th order)...
With the right driver (which is key) you can really squeeze a lot of decibels out without too much input power(good efficiency), using a cabinet size that is not too outlandish in my opinion, at least that has been my experience with the Eigenmode versions of the 8th order simulations .....
Might be an adventurous option to try out if you have one of those Beyma 15s laying around or a Definimax12 and want to do something unique and experimental
Be the first guy in the world to build and own one! Could make a good PA sub in a portable package as long as you aren't needing to get below the 35-40hz range.@ freddi
Yeah, SubSim is something i just remembered i had ! It's a while since i used it, & it was way ahead of it's time when released. I suppose it still is in some respects
Subwoofer Simulator can help with these designs.
- Closed-Box
- Vented-Box
- Passive Radiator
- 4th-Order Bandpass
- 6th-Order Bandpass - I
- 6th-Order Bandpass - II
- 8th-Order Bandpass
I might try it out again
@ Matthew Morgan J
Nice going, as always
Yeah, SubSim is something i just remembered i had ! It's a while since i used it, & it was way ahead of it's time when released. I suppose it still is in some respects
Subwoofer Simulator can help with these designs.
- Closed-Box
- Vented-Box
- Passive Radiator
- 4th-Order Bandpass
- 6th-Order Bandpass - I
- 6th-Order Bandpass - II
- 8th-Order Bandpass
I might try it out again
@ Matthew Morgan J
Nice going, as always
one could add an additional vented chamber in front of a normal 6th order series vented or parallel vented bandpass box - advantages
= I don't know - a simulator would really help
Bose for years has used a triple chamber Bose Acoustimass 5 series II transparent - What's Inside
An externally hosted image should be here but it was not working when we last tested it.
Attachments
Here we go
Alright guys, here it is
Arranged as a classic Helmholtz 8th order bandpass like David pointed out in the post above, using David's new "BP8" feature that he recently added to his wonderful software Hornresp ...
You can reach the new BP8 mode by holding down your CTRL key while clicking through all of the different alignment options ...
This cabinet is only 86.6 liters net , and we get nearly 120db out of a Definimax12 down to 40hz .... Response looks like it extends up to almost 170 or 180hz ....
Although the second and third resonance display in red letters (at the lower right in sim) as 120hz and 140hz the interactions between the different chambers and ports in this cabinet shift those resonances to 80hz and 170hz , so the set of effective resonances that we actually end up with are 40hz , 80hz and 170hz evidenced by the minimums on the Impedance graph and the nulls in the cone displacement graph ....
These pictures show the HR inputs, settings for each chamber, and i provided an export file as well... Everything a person needs to load this into their own install of HR ...
Anyway , (like i said about the Eigenmode version of these 8th order cabs) these simulations really do look fantastic but only for very specific drivers .... The low-ish VAS figure, along with an FS figure that is not too low combined with the relatively high motor strength of the Definimax12 allow the cabinet size to remain small while extension and output remain sterling!
Alright guys, here it is
Arranged as a classic Helmholtz 8th order bandpass like David pointed out in the post above, using David's new "BP8" feature that he recently added to his wonderful software Hornresp ...
You can reach the new BP8 mode by holding down your CTRL key while clicking through all of the different alignment options ...
This cabinet is only 86.6 liters net , and we get nearly 120db out of a Definimax12 down to 40hz .... Response looks like it extends up to almost 170 or 180hz ....
Although the second and third resonance display in red letters (at the lower right in sim) as 120hz and 140hz the interactions between the different chambers and ports in this cabinet shift those resonances to 80hz and 170hz , so the set of effective resonances that we actually end up with are 40hz , 80hz and 170hz evidenced by the minimums on the Impedance graph and the nulls in the cone displacement graph ....
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
These pictures show the HR inputs, settings for each chamber, and i provided an export file as well... Everything a person needs to load this into their own install of HR ...
Anyway , (like i said about the Eigenmode version of these 8th order cabs) these simulations really do look fantastic but only for very specific drivers .... The low-ish VAS figure, along with an FS figure that is not too low combined with the relatively high motor strength of the Definimax12 allow the cabinet size to remain small while extension and output remain sterling!
Hi MMJ,
Well done - it's not easy coming up with a satisfactory BP8 response!
I have taken a copy of your export file for future reference - thanks for making it available.
Kind regards,
David
Operation of the super secret modes! *mission impossible theme song plays*
Hi Freddy!
You just change the modes as you normally would by clicking on the alignment type repeatedly and it goes through all of the options , ND , OD, CH, TH etc etc etc , but if you then hold down your CTRL key the extra new modes will suddenly show up while clicking through the options .... ME , BP6 , BP8, ABC ....
In BP8 mode there is no "calculate" button like you would normally see on the lower right, it now just says "Wizard" , clicking on that button allows you to go in and edit the design by using the handy sliders ...... Of course you can also manually enter the inputs the old fashioned way, but in this mode you will need to use the Wizard to view the schematic and various graphs because as far as i can tell these things are not available outside of the Wizard (Unlike the non-hidden modes that are typically used in HR)
The schematic really doesn't change (at least not in the way to which we are accustomed) when you are adjusting chamber volumes, dimensions or vent lengths , the schematic just seems to be there to give you an idea of how all of these parts are arranged and lets you know which part of the box you are adjusting at the moment by turning that particular section yellow when you are making a change ... (So the schematic also functions in a way that is very different from the standard HR modes)
Freddi ,
Cheerful maybe, but cheap could be tricky.... It is harder to find the driver's with ideal specs for this box , and the strong motor feature is usually something found in pricier drivers ...........
Now that I think about it I could try one of the Soundqubed drivers in this box, their subs have oodles of motor strength and low VAS figures and are affordable ..
Hi Freddy!
You just change the modes as you normally would by clicking on the alignment type repeatedly and it goes through all of the options , ND , OD, CH, TH etc etc etc , but if you then hold down your CTRL key the extra new modes will suddenly show up while clicking through the options .... ME , BP6 , BP8, ABC ....
In BP8 mode there is no "calculate" button like you would normally see on the lower right, it now just says "Wizard" , clicking on that button allows you to go in and edit the design by using the handy sliders ...... Of course you can also manually enter the inputs the old fashioned way, but in this mode you will need to use the Wizard to view the schematic and various graphs because as far as i can tell these things are not available outside of the Wizard (Unlike the non-hidden modes that are typically used in HR)
The schematic really doesn't change (at least not in the way to which we are accustomed) when you are adjusting chamber volumes, dimensions or vent lengths , the schematic just seems to be there to give you an idea of how all of these parts are arranged and lets you know which part of the box you are adjusting at the moment by turning that particular section yellow when you are making a change ... (So the schematic also functions in a way that is very different from the standard HR modes)
Freddi ,
Cheerful maybe, but cheap could be tricky.... It is harder to find the driver's with ideal specs for this box , and the strong motor feature is usually something found in pricier drivers ...........
Now that I think about it I could try one of the Soundqubed drivers in this box, their subs have oodles of motor strength and low VAS figures and are affordable ..
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No problem at all David !!
I experimented around with these modes a little bit, back when you first added them
I am really glad to be able to help ,
Thank you for making these softwares available for the DIY crowd!
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hey MMJ - tweak a BP8 for PA310-8 - this ain't rite
Hehe , there you go! ahh yes The PA-310 is a pretty good idea! Looks like you tuned a little higher (FB of 50 to 55hz i am guessing?) That is some great output for 34 volts into an affordable pro 12
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