i have read the suggested threads in response to my search for ripoles and found no answer to my question. I read this site Jazzman's DIY Electrostatic Loudspeaker Page: Ripole Subwoofers: and sent him a reply, but, so far, no answer so I would like to throw these questions out to the forum.
Hi Jazzman, I read with interest your post on RIPOLE sub. I have read the original webpage by Axel Reidenthaler ( sp?), but your pictures and assembly plans seem much easier to follow😉 Maybe I' m just not good at interpreting plans. However, I have a couple of questions.
1. Why do the magnets have to poke through the sides of the ripoles? Is it a necessity to brace the drivers or enclosure, or to reduce the overall width of the ripoles? Not doing this would allow the fitting of various drivers to assess their suitability and certainly improve the aesthetics and make for an easier build. At low frequencies in these enclosures, could I surface mount drivers?
2. Could I get away with lower Qts value woofers or (heresy alert) even bass drivers that are similar but not identical, either in each ripole or in each pair of ripoles. I plan to experiment, but just wondered if you or anyone else has tried this approach. Why I ask is that I have a bunch of very similar 12" bass drivers (in pairs) just sitting around. I'm thinking that mismatched drivers in an enclosure or two enclosures with different (matched) pairs of drivers either might not matter or even complement each other because of slightly different resonances, peaks and dips etc which would tend to even out the response of pairs in the enclosures and room. I plan on bi-amping bass and FR with active XO. SS amp on Bass and valve amp on FR so sensitivities not an issue. Medium SPL in medium sized room.
BTW The woofers are all 8 ohm and I have a 4- channel amp that I could use to power each driver separately if needed or pair drivers in parallel or series for 4 or 16 ohm loads etc. Amp can drive 4 ohm loads and has inbuilt bridging circuits that allows 2, 3 or 4 channel operation approx 45w/ch (RMS) in 4 channel mode and screwdriver adjustable level controls for each channel.
Any suggestions very welcome.
Ozziozzi
Hi Jazzman, I read with interest your post on RIPOLE sub. I have read the original webpage by Axel Reidenthaler ( sp?), but your pictures and assembly plans seem much easier to follow😉 Maybe I' m just not good at interpreting plans. However, I have a couple of questions.
1. Why do the magnets have to poke through the sides of the ripoles? Is it a necessity to brace the drivers or enclosure, or to reduce the overall width of the ripoles? Not doing this would allow the fitting of various drivers to assess their suitability and certainly improve the aesthetics and make for an easier build. At low frequencies in these enclosures, could I surface mount drivers?
2. Could I get away with lower Qts value woofers or (heresy alert) even bass drivers that are similar but not identical, either in each ripole or in each pair of ripoles. I plan to experiment, but just wondered if you or anyone else has tried this approach. Why I ask is that I have a bunch of very similar 12" bass drivers (in pairs) just sitting around. I'm thinking that mismatched drivers in an enclosure or two enclosures with different (matched) pairs of drivers either might not matter or even complement each other because of slightly different resonances, peaks and dips etc which would tend to even out the response of pairs in the enclosures and room. I plan on bi-amping bass and FR with active XO. SS amp on Bass and valve amp on FR so sensitivities not an issue. Medium SPL in medium sized room.
BTW The woofers are all 8 ohm and I have a 4- channel amp that I could use to power each driver separately if needed or pair drivers in parallel or series for 4 or 16 ohm loads etc. Amp can drive 4 ohm loads and has inbuilt bridging circuits that allows 2, 3 or 4 channel operation approx 45w/ch (RMS) in 4 channel mode and screwdriver adjustable level controls for each channel.
Any suggestions very welcome.
Ozziozzi
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Hi,
A1: One smart thing about the Ripoles is their small size. The small dimensions lead to a considerable reduction in the drivers base resonance fs. As a rule of thumb .. the smaller the size, the more the reduction. When working with drivers of a certain set of parameters it was realized that the dimensions of the cabinet could become smaller than the drivers could fit. So it was obvious that the magnets protruded through the side walls.
Many drivers also feature a pole piece ventilation that should not be covered.
It'd rather be better to have the vent outside the box than to 'close' it with the cabinets side wall.
Of course could one widen the cabinet by widening at least two of the three chambers or by simply making the side walls thicker, but the first will lead to a slightly different tuning of the system and the second might look clumsy.
!How big or small You choose to built is simply Your choice.
The Linkwitz Dipoles for example built larger and Linkwitz seems to prefer drivers with considerably lower Qt and the accessability of the drivers is better.
Those dipoles require more electronic equalization though and don't look as small and smart -well, to my eyes at least. 😉
But no one hinders You to build a Ripole such that You can easily access and change the drivers. You may mount the drivers after Your fashion.
Surface mounting of the drivers could reduce the middle chambers volume a little bit though and You might want to correct for that by making the chamber wider by a few mm. Die to beeing the typically smallest volume of the three chambers the middle chamber dominates the behaviour of the whole system.
Variations in the two outer chambers volume doesn't change the systems behaviour as much.
A2: You can use lower Qt drivers, but those require more equalization towards the low bass. Apart from this its my experience that the well suited Qt range also depends on driver size. For the 6"-8" class I'd opt for Qts from ~0.4-0.6 lowering to 0.3-0.35 for 18"ers (just a rough rule of thumb .... I've heard 18"ers with Qts up to 0.9 perform reasonably well also).
Linkwitz seems to prefer lower-Qt/low-fs drivers for his designs.
I haven't tried different drivers together in a Ripole, but I'd opt against it as I doubt that it'd lead to the benefits You mentioned.
But Your are of course free and welcome to do Your own experiments.
jauu
Calvin
btw: his name spells Axel Ridtahler 😉 He's a friendly and helpful guy whom You can ask personally also.
A1: One smart thing about the Ripoles is their small size. The small dimensions lead to a considerable reduction in the drivers base resonance fs. As a rule of thumb .. the smaller the size, the more the reduction. When working with drivers of a certain set of parameters it was realized that the dimensions of the cabinet could become smaller than the drivers could fit. So it was obvious that the magnets protruded through the side walls.
Many drivers also feature a pole piece ventilation that should not be covered.
It'd rather be better to have the vent outside the box than to 'close' it with the cabinets side wall.
Of course could one widen the cabinet by widening at least two of the three chambers or by simply making the side walls thicker, but the first will lead to a slightly different tuning of the system and the second might look clumsy.
!How big or small You choose to built is simply Your choice.
The Linkwitz Dipoles for example built larger and Linkwitz seems to prefer drivers with considerably lower Qt and the accessability of the drivers is better.
Those dipoles require more electronic equalization though and don't look as small and smart -well, to my eyes at least. 😉
But no one hinders You to build a Ripole such that You can easily access and change the drivers. You may mount the drivers after Your fashion.
Surface mounting of the drivers could reduce the middle chambers volume a little bit though and You might want to correct for that by making the chamber wider by a few mm. Die to beeing the typically smallest volume of the three chambers the middle chamber dominates the behaviour of the whole system.
Variations in the two outer chambers volume doesn't change the systems behaviour as much.
A2: You can use lower Qt drivers, but those require more equalization towards the low bass. Apart from this its my experience that the well suited Qt range also depends on driver size. For the 6"-8" class I'd opt for Qts from ~0.4-0.6 lowering to 0.3-0.35 for 18"ers (just a rough rule of thumb .... I've heard 18"ers with Qts up to 0.9 perform reasonably well also).
Linkwitz seems to prefer lower-Qt/low-fs drivers for his designs.
I haven't tried different drivers together in a Ripole, but I'd opt against it as I doubt that it'd lead to the benefits You mentioned.
But Your are of course free and welcome to do Your own experiments.
jauu
Calvin
btw: his name spells Axel Ridtahler 😉 He's a friendly and helpful guy whom You can ask personally also.
Hi ozziozzi,
As to your amplifier connections: it is my understanding, that the passive filter elements suggested for use with the Ripol are driver specific parts of the design, and should not simply be replaced with an active crossover. Maybe Calvin can shed some more light on that subject.
Regards,
As to your amplifier connections: it is my understanding, that the passive filter elements suggested for use with the Ripol are driver specific parts of the design, and should not simply be replaced with an active crossover. Maybe Calvin can shed some more light on that subject.
Regards,
Attachments
Ripoles etc
calvin, thanks for your comments. The woofers I want to use are not vented and are fairly shallow designs. One pair has a Qts of about 0.6 so they should be ok in small ripole without complicated EQ ala Linkwitz. Not sure of other woofers, but they are similar design. My point about amp is that I can account for different sensitivities easily with all 4 channels easily adjustable. Active XO is adjustable for hi and lowpass from 80Hz to 5 kHz and slope switchable 12 and 24 dB/ octave. I am thinking lowpass at about 160-200 @ 24dB/oct. My test CD would be Bela Fleck and the Flecktones live at the Quick 🙂)
I looked at your website (amazing craftsmanship and designs) and noticed you had a ripole (@ Wetzlar) which appeared to only have one very large driver. Was that a 40cm (15") or larger? I have a pair of 15" Qts 0.28 woofers with Fs of 40Hz and 250W rating that might suit that style of ripole. Does it work as well as the push-push system? I am mainly trying to avoid the wide flat OB panel required for 15" driver. I had not considered a ripole for a single driver.
Tb46, the diagram you attached seems, to my limited knowledge, to be part of a passive Sub XO first-order 6 dB/oct at about 135 Hz (assuming the drivers are 8ohms each) plus some sort of correction network. I am not sure what that is supposed to achieve. Perhaps others can comment on it.
Since I plan to use active Lowpass at about 160-200 Hz I will not need an inductor between the amp and driver(s). Hopefully This will avoid cavity or driver resonances and not require extra passive components on the driver. Only time will tell. The drivers I can use have an Fs about 40Hz. If what I read about ripoles is true, this may result in usable output at 30Hz, good enough for me. I am mainly into Jazz, blues, modern adult contemporary, folk, modern country. What I am really thinking about is a FAST system, Fullrange plus "helper" woofer.
calvin, thanks for your comments. The woofers I want to use are not vented and are fairly shallow designs. One pair has a Qts of about 0.6 so they should be ok in small ripole without complicated EQ ala Linkwitz. Not sure of other woofers, but they are similar design. My point about amp is that I can account for different sensitivities easily with all 4 channels easily adjustable. Active XO is adjustable for hi and lowpass from 80Hz to 5 kHz and slope switchable 12 and 24 dB/ octave. I am thinking lowpass at about 160-200 @ 24dB/oct. My test CD would be Bela Fleck and the Flecktones live at the Quick 🙂)
I looked at your website (amazing craftsmanship and designs) and noticed you had a ripole (@ Wetzlar) which appeared to only have one very large driver. Was that a 40cm (15") or larger? I have a pair of 15" Qts 0.28 woofers with Fs of 40Hz and 250W rating that might suit that style of ripole. Does it work as well as the push-push system? I am mainly trying to avoid the wide flat OB panel required for 15" driver. I had not considered a ripole for a single driver.
Tb46, the diagram you attached seems, to my limited knowledge, to be part of a passive Sub XO first-order 6 dB/oct at about 135 Hz (assuming the drivers are 8ohms each) plus some sort of correction network. I am not sure what that is supposed to achieve. Perhaps others can comment on it.
Since I plan to use active Lowpass at about 160-200 Hz I will not need an inductor between the amp and driver(s). Hopefully This will avoid cavity or driver resonances and not require extra passive components on the driver. Only time will tell. The drivers I can use have an Fs about 40Hz. If what I read about ripoles is true, this may result in usable output at 30Hz, good enough for me. I am mainly into Jazz, blues, modern adult contemporary, folk, modern country. What I am really thinking about is a FAST system, Fullrange plus "helper" woofer.
With larger woofers, you may have issues crossing that high.
Do you know the xmax of your woofers?
Do you know the xmax of your woofers?
Hi,
the original Ripoles come with the passive EQ-network, which forms a Notch-Filter that kills the chamber resonance around 250Hz (+-100Hz, depending on the dimensions of the chambers).
This filter may be implemented with active technology .... its just not a original Ripole anymore 😉
The first patent granted to Axel described the Dual-driver Dipole bass (named BMC BlowMotionConcept ... whatever that meant).
A later second patent of Axel and his compagnion Richard Lohnert described single-driver dipols too (named DRS -DynamicResonanceSinking)
The only difference between both are the Dual-drivers respective the single-driver and as such the force/momentum-cancelletion of the Dual-system.
Force cancellation with the singles could be achieved by stacking two DRS-dipoles side bay side or (but only to a great degree) by stacking the DRSses vertically.
The same design rules apply to both.
A 12" driver with a Qts of 0.6, a Fs of 40Hz and no pole vent sounds like a cheap driver (though a value set of 0.6 and 40Hz alone sounds fine).
The small Ripole lowers the Fs considerably ... up to 15Hz, but typically around 5-10Hz.
Quite a large number of 15" PA-drivers are very suitable for this application.
You may want to test first how much excursion it can do and if it can do large strokes without becoming noisy.
Just drive the basses free-air with a very low frequency and increase the power.
Every driver sooner or later starts generating wind noise or rub-and-buzz.
Beeing an open system this will be audible in the finished dipole also.
It´d also be good if You could measure the TSPs and amplitude and impedance response of the driver.
Then it´s possible to calculate/sim the dimensions and the dipole behaviour quite exact.
jauu
Calvin
ps. Thanks btw for Your nice comment 😉
the original Ripoles come with the passive EQ-network, which forms a Notch-Filter that kills the chamber resonance around 250Hz (+-100Hz, depending on the dimensions of the chambers).
This filter may be implemented with active technology .... its just not a original Ripole anymore 😉
The first patent granted to Axel described the Dual-driver Dipole bass (named BMC BlowMotionConcept ... whatever that meant).
A later second patent of Axel and his compagnion Richard Lohnert described single-driver dipols too (named DRS -DynamicResonanceSinking)
The only difference between both are the Dual-drivers respective the single-driver and as such the force/momentum-cancelletion of the Dual-system.
Force cancellation with the singles could be achieved by stacking two DRS-dipoles side bay side or (but only to a great degree) by stacking the DRSses vertically.
The same design rules apply to both.
A 12" driver with a Qts of 0.6, a Fs of 40Hz and no pole vent sounds like a cheap driver (though a value set of 0.6 and 40Hz alone sounds fine).
The small Ripole lowers the Fs considerably ... up to 15Hz, but typically around 5-10Hz.
Quite a large number of 15" PA-drivers are very suitable for this application.
You may want to test first how much excursion it can do and if it can do large strokes without becoming noisy.
Just drive the basses free-air with a very low frequency and increase the power.
Every driver sooner or later starts generating wind noise or rub-and-buzz.
Beeing an open system this will be audible in the finished dipole also.
It´d also be good if You could measure the TSPs and amplitude and impedance response of the driver.
Then it´s possible to calculate/sim the dimensions and the dipole behaviour quite exact.
jauu
Calvin
ps. Thanks btw for Your nice comment 😉
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Calvin, I guessed that the network had such a function, but I was not sure of the exact range of frequencies affected. if I LowPass at about 100Hz (would work for me) @ 24dB/oct I should avoid cavity resonances at 250 +\- 100Hz without resorting to further LC networks on bass drivers--or at least reduce them to a very low level--right?
You are correct about cheap 12" drivers. One pair are Jaycar 2119 that several people on this forum have used successfully in OB, Others are SONY, AKAI and Technics salvaged from 70s and 80s 3-way sealed or ported enclosures.
Face, The 12" drivers were originally crossed over at 500-600 in a three-way, the 15" are pro drivers Fs 40 rated at 200W RMS I have previously crossed them to a horn at ~3kHz (similar to Wayne Parhams 4Pi design in a bass reflex ) and they sounded good. I will be driving them with a 90W/ch SS pro amp. Re : X-max etc, All I can say is *adequate* Xmax considering the Large cone surface and I only need modest levels for personal listening in a small to medium room. I will see how the various drivers sound in their respectively-sized ripoles.
Thanks for all your interest in my project and warnings of possible problems, now it is time to begin construction and listening tests.
As I may have mentioned before, I just want a bit of bass support for a FR OB. Flat OB bass or large sealed or ported boxes just takes up too much space so I am hoping that ripoles with either single or dual driver will suit my purpose. I *can* get into more exact mathematical and physical planning, but I prefer to just play with system and see how it sounds. It is a hobby, not a business and I have limited time available, so TSP tests of drivers (all salvaged) will not happen. If someone would like to visit me in Australia to perform these tests please PM me 😉
You are correct about cheap 12" drivers. One pair are Jaycar 2119 that several people on this forum have used successfully in OB, Others are SONY, AKAI and Technics salvaged from 70s and 80s 3-way sealed or ported enclosures.
Face, The 12" drivers were originally crossed over at 500-600 in a three-way, the 15" are pro drivers Fs 40 rated at 200W RMS I have previously crossed them to a horn at ~3kHz (similar to Wayne Parhams 4Pi design in a bass reflex ) and they sounded good. I will be driving them with a 90W/ch SS pro amp. Re : X-max etc, All I can say is *adequate* Xmax considering the Large cone surface and I only need modest levels for personal listening in a small to medium room. I will see how the various drivers sound in their respectively-sized ripoles.
Thanks for all your interest in my project and warnings of possible problems, now it is time to begin construction and listening tests.
As I may have mentioned before, I just want a bit of bass support for a FR OB. Flat OB bass or large sealed or ported boxes just takes up too much space so I am hoping that ripoles with either single or dual driver will suit my purpose. I *can* get into more exact mathematical and physical planning, but I prefer to just play with system and see how it sounds. It is a hobby, not a business and I have limited time available, so TSP tests of drivers (all salvaged) will not happen. If someone would like to visit me in Australia to perform these tests please PM me 😉
I'm stating that the top end may be limited due to the dipole peak, not the driver's inherent response.
Drivers with a large xmax are required as this design, due to the bottom end boost, will eat up excursion quickly.
Some car audio woofers work well in Ripoles. Check out the JBL GT5-15.
Drivers with a large xmax are required as this design, due to the bottom end boost, will eat up excursion quickly.
Some car audio woofers work well in Ripoles. Check out the JBL GT5-15.
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