Hi I'm planning to try out a ripole woofer design. I've shortlisted two drivers
The Eminence:
- KAPPA PRO-15B with a Qts of 0.31
- Delta 15B with a Qts of 0.62
The Monacor SP-382 PA, is used in Ripole designs I come across and has a Qts 0.75, but not the right impendance for me.
I need 16Ohm drivers to keep the total at a resonable level, otherwise I shortlisted these Eminence drivers for the following reasons:
- They are well reviewed,
- High efficiency +/-100dB
- Papercone and surrround, similair to the full-range driver they will augment.
- Affordable
-They have a reasonable midrange, so cone break up will be well out of the way after filtering.
I'm planning to filter very low at about 100Hz first order with a single coil.
Any suggestions?
I've used the Wavecor Excellsheet to calculate Sd and it estimates a possible 43Hz..
The Eminence:
- KAPPA PRO-15B with a Qts of 0.31
- Delta 15B with a Qts of 0.62
The Monacor SP-382 PA, is used in Ripole designs I come across and has a Qts 0.75, but not the right impendance for me.
I need 16Ohm drivers to keep the total at a resonable level, otherwise I shortlisted these Eminence drivers for the following reasons:
- They are well reviewed,
- High efficiency +/-100dB
- Papercone and surrround, similair to the full-range driver they will augment.
- Affordable
-They have a reasonable midrange, so cone break up will be well out of the way after filtering.
I'm planning to filter very low at about 100Hz first order with a single coil.
Any suggestions?
I've used the Wavecor Excellsheet to calculate Sd and it estimates a possible 43Hz..
Hi,
both drivers have only a very limited excursion limit, which makes them rather useless for Ripoles.
Eminence alternatives with proper set of parameters could be the Kilomax Pro 15A, the Definimax 4015LF or the LAB 15.
With the size of the front chamber You can tune the resonance frequency and Qt a bit.
the smaller the chamber the lower the Fb.
In extreme You can achieve Fb of up to 15Hz lower than the Fs.
My experince is, that larger drivers allow for lower Qts without he need of equalization/bass boost.
Between 0.35 and 0.5 seems optimal to me for 15"er.
jauu
Calvin
both drivers have only a very limited excursion limit, which makes them rather useless for Ripoles.
Eminence alternatives with proper set of parameters could be the Kilomax Pro 15A, the Definimax 4015LF or the LAB 15.
With the size of the front chamber You can tune the resonance frequency and Qt a bit.
the smaller the chamber the lower the Fb.
In extreme You can achieve Fb of up to 15Hz lower than the Fs.
My experince is, that larger drivers allow for lower Qts without he need of equalization/bass boost.
Between 0.35 and 0.5 seems optimal to me for 15"er.
jauu
Calvin
Thanks Calvin,
Thanks for pointing this out, I didn't know excursion was that critical. De Kappa Pro does 13.2mm XMax, where as the Definimax does 15.5mm XMax.
I like the look of the Definimax and know Nelson Pass used one with great success in a dipole, something I took inspiration from. However I need a higher impedance.
Any more suggestion?
Thanks for pointing this out, I didn't know excursion was that critical. De Kappa Pro does 13.2mm XMax, where as the Definimax does 15.5mm XMax.
I like the look of the Definimax and know Nelson Pass used one with great success in a dipole, something I took inspiration from. However I need a higher impedance.
Any more suggestion?
Hi,
I don't what your talking about regarding tuning of a ripole.
Or what box arrangement with Fb the above applies to.
rgds, sreten.
Hi,
well, the thread is about Ripoles and my post deals with Ripoles
In case You´re unfamiliar with Ripoles ....
They are variants of Dipole Basses.
They are characterized by comparatively very small open chambers for the front and backside of the driver diaphragm.
They comprise a Dipole of folded Baffle style.
Using two drivers facing each other, two of the chambers may be joined into one chamber that both drivers use at the same.
This way the more commonly known 2-driver-3-chamber structure develops.
Due to their smallness the chambers add a serious dynamic load to the drivers which leads to the lowering of Fs and raise of Qts.
The smallest chamber shows the greatest effect and depending on the driver parameters Fs may sink by up to 15Hz.
With larger dimensions as for e.g in the folded dipoles after S.Linkwitz or plain open baffles the driver´s Fs and Qts remain rather unchanged.
So, driver parameters shall differ between a small and a large folded dipole.
While verylow Fs and Qts drivers are suggested by SL (12"/20Hz/0.2), the drivers for a ripole may preferrably be of medium Fs and medium to high Qts (15"/25-35Hz/0.35-0.5).
One finds the parameter set 35Hz/0.35 in many Pro-audio drivers.
Fortunately over the last years more and more drivers occur with raised excursion capability.
Beyma 15LX60, FaitalPro 15FH500 and 15FH520, BMS 15N850, Eminence LAB15, RCF 15 LP200AK, and some more.
As with all dipoles, the wavelengths within the working range are lareg compared to the baffle dimensions, hence they suffer from acoustic phase cancellation.
The effect is that for same SPL the excursion of the diaphragm is larger than with other cabinet styles, hence the need for longthrow drivers (requirement to move more air volume).
Larger sized drivers and/or Arrays of drivers allow to trade membrane excursion against membrane area.
jauu
Calvin
well, the thread is about Ripoles and my post deals with Ripoles
In case You´re unfamiliar with Ripoles ....
They are variants of Dipole Basses.
They are characterized by comparatively very small open chambers for the front and backside of the driver diaphragm.
They comprise a Dipole of folded Baffle style.
Using two drivers facing each other, two of the chambers may be joined into one chamber that both drivers use at the same.
This way the more commonly known 2-driver-3-chamber structure develops.
Due to their smallness the chambers add a serious dynamic load to the drivers which leads to the lowering of Fs and raise of Qts.
The smallest chamber shows the greatest effect and depending on the driver parameters Fs may sink by up to 15Hz.
With larger dimensions as for e.g in the folded dipoles after S.Linkwitz or plain open baffles the driver´s Fs and Qts remain rather unchanged.
So, driver parameters shall differ between a small and a large folded dipole.
While verylow Fs and Qts drivers are suggested by SL (12"/20Hz/0.2), the drivers for a ripole may preferrably be of medium Fs and medium to high Qts (15"/25-35Hz/0.35-0.5).
One finds the parameter set 35Hz/0.35 in many Pro-audio drivers.
Fortunately over the last years more and more drivers occur with raised excursion capability.
Beyma 15LX60, FaitalPro 15FH500 and 15FH520, BMS 15N850, Eminence LAB15, RCF 15 LP200AK, and some more.
As with all dipoles, the wavelengths within the working range are lareg compared to the baffle dimensions, hence they suffer from acoustic phase cancellation.
The effect is that for same SPL the excursion of the diaphragm is larger than with other cabinet styles, hence the need for longthrow drivers (requirement to move more air volume).
Larger sized drivers and/or Arrays of drivers allow to trade membrane excursion against membrane area.
jauu
Calvin
Thanks guys.
Calvin, I had a look at your website, you make some great looking audio gear. You obviously know your stuff.
I think the Eminence Kappa Pro 15B is the best compromise I will find in 16Ohm driver.
What do you guys think about trying to cross-over @ +/- 100Hz with just a single coil., is this feasible (I'd rather not go the Bi-amp route)? I understand this large a coil will impact dampening, but how critical is this at these low frequencies? How liniear can I expect the Ripole to stay below 100Hz, I've not found any measured data on this. Any pointers would be apprecaited.
I'm planning to integrate the Ripole front slot into a large baffle, so hopefully this will deal with accoustic shortage better.
Calvin, I had a look at your website, you make some great looking audio gear. You obviously know your stuff.
I think the Eminence Kappa Pro 15B is the best compromise I will find in 16Ohm driver.
What do you guys think about trying to cross-over @ +/- 100Hz with just a single coil., is this feasible (I'd rather not go the Bi-amp route)? I understand this large a coil will impact dampening, but how critical is this at these low frequencies? How liniear can I expect the Ripole to stay below 100Hz, I've not found any measured data on this. Any pointers would be apprecaited.
I'm planning to integrate the Ripole front slot into a large baffle, so hopefully this will deal with accoustic shortage better.
Hi,
Your hint regarding using a coil reminded me of something I miussed saying.
A Ripole implemented properly features a passive EQ network.
This consists of a series inductor with a copper resistance of 0.3-0.6 and a parallel RCL network.
Whereby only the ohmic part of the inductor is required for the notch filter to work on.
The inductive part could be omitted with, but it performs a very welcome lowpass functionality.
The slight raise of the Qts due to the series ´resistance´ counters for the losses of the inductor ... so efficiency won´t be affected -> no loss of SPL.
Inductors with higher dc-resistance are quite cheap.
See for example the I-Kern inductors at Intertechnik.de (pic below).
Without that circuit its just a small folded dipole.
The network comprises a lowpass and a notch filter to cope with the chamber resonance (typically ~200-300Hz, depending on the cabinet dimensions).
Besides increasing Qt slightly, the Fs drops even more.
The impedance response also drops in value and the minimum, somewhere between 100-200Hz, should be watched if teh amplifier can drive that load safely.
It is not a necessity to use highohmic drivers and to connect the drivers in parallel ... the series connection of 4-ohmers works well also.
jauu
Calvin
ps.
It is to understand that the cabinet already is a baffle, just a folded one.
Your hint regarding using a coil reminded me of something I miussed saying.
A Ripole implemented properly features a passive EQ network.
This consists of a series inductor with a copper resistance of 0.3-0.6 and a parallel RCL network.
Whereby only the ohmic part of the inductor is required for the notch filter to work on.
The inductive part could be omitted with, but it performs a very welcome lowpass functionality.
The slight raise of the Qts due to the series ´resistance´ counters for the losses of the inductor ... so efficiency won´t be affected -> no loss of SPL.
Inductors with higher dc-resistance are quite cheap.
See for example the I-Kern inductors at Intertechnik.de (pic below).
Without that circuit its just a small folded dipole.
The network comprises a lowpass and a notch filter to cope with the chamber resonance (typically ~200-300Hz, depending on the cabinet dimensions).
Besides increasing Qt slightly, the Fs drops even more.
The impedance response also drops in value and the minimum, somewhere between 100-200Hz, should be watched if teh amplifier can drive that load safely.
It is not a necessity to use highohmic drivers and to connect the drivers in parallel ... the series connection of 4-ohmers works well also.
jauu
Calvin
ps.
This will change to whole dimensioning.
It is to understand that the cabinet already is a baffle, just a folded one.
Attachments
Last edited:
Thanks Calvin, some great tips. The 200-300Hz notch filter is a great idea, do you still think I need it if my LPF is at 100Hz, using a single 25-27mH transformer inductor?
I’m planning to use a single driver, so putting them in series is not an option. Keeping the total (three way) system impedance at a reasonable level is a main concern. Efficiency is less of a concern.
I don’t quite understand why putting the Ripole into a baffle is a concern. Doesn’t it just make the total effective baffle bigger thereby reducing the effect of acoustic shortage even more, which should be a good thing. I thought the key to the Ripole design is the slotloading in combination with the baffle effect of the rear chamber (compared to the Dipole).
This is the inductor I was thinking of:
Audio Tschentscher | Lautsprecherreparatur | Lautsprecherentwicklung | HIFI - High End Trafo Spule Audio-Tschentscher, Feron Trafospule 27,00 mH, Produktion Audio Spul
I’m planning to use a single driver, so putting them in series is not an option. Keeping the total (three way) system impedance at a reasonable level is a main concern. Efficiency is less of a concern.
I don’t quite understand why putting the Ripole into a baffle is a concern. Doesn’t it just make the total effective baffle bigger thereby reducing the effect of acoustic shortage even more, which should be a good thing. I thought the key to the Ripole design is the slotloading in combination with the baffle effect of the rear chamber (compared to the Dipole).
This is the inductor I was thinking of:
Audio Tschentscher | Lautsprecherreparatur | Lautsprecherentwicklung | HIFI - High End Trafo Spule Audio-Tschentscher, Feron Trafospule 27,00 mH, Produktion Audio Spul
Well said, .. don't underestimate swept volume when selecting ripole drivers. They need it.
Hi all,
My SLS Ripoles were a big hit with the guys at Carverfest last week. One of my Carver buddies just purchased four 15" AE woofers (see link below) for an IB project but he now wants me to build some Ripole boxes for them.
AE Speakers --- Superb Quality, Unforgettable Performance, Definitely.
I'm thinking their 17 Hz FS is too low and their .7 Qts may be too high for a Ripole application. But my buddy is insistent about this so my question is: Could these drivers be made to work in a Ripole if the slot areas were made larger?
If a Ripole wouldn't work, how about a Linkwitz push/pull?
My SLS Ripoles were a big hit with the guys at Carverfest last week. One of my Carver buddies just purchased four 15" AE woofers (see link below) for an IB project but he now wants me to build some Ripole boxes for them.
AE Speakers --- Superb Quality, Unforgettable Performance, Definitely.
I'm thinking their 17 Hz FS is too low and their .7 Qts may be too high for a Ripole application. But my buddy is insistent about this so my question is: Could these drivers be made to work in a Ripole if the slot areas were made larger?
If a Ripole wouldn't work, how about a Linkwitz push/pull?
Hi,
well, they would ´work´ in a Ripole, but the outcome wouldn´t do the drivers nor the principle justice.
It´d be far off of optimum.
While the Qts is just so at the upper limit of the requirement, the low Fs renders the driver unsuitable for a good Ripole.
It is intended for IB useage and that´s where it could probabely shine.
If one insists on a folded Dipole it´d be a large sized one.
The Linkwitz might work ... at least it´s design would be better suited for the driver.
The chambers should be sized so that the Fs wouldn´t drop .. or as low a possible.
The passive filter network which is inherent to a original Ripole design sinks the driver´s Fs considerably.
The Linkwitz design doesn´t use this filter network, but only active filtering, which doesn´t sink the Fs.
If Your Buddy still insists on a true Ripole design, I can only recommend out of bad experience to withdraw from that project and save Your good reputation.
In the end You might end up being made responsible for the fail or suboptimal outcome.
If people insist on making failures against sound advice let them make the failures ... but their´s not Your´s.
jauu
Calvin
well, they would ´work´ in a Ripole, but the outcome wouldn´t do the drivers nor the principle justice.
It´d be far off of optimum.
While the Qts is just so at the upper limit of the requirement, the low Fs renders the driver unsuitable for a good Ripole.
It is intended for IB useage and that´s where it could probabely shine.
If one insists on a folded Dipole it´d be a large sized one.
The Linkwitz might work ... at least it´s design would be better suited for the driver.
The chambers should be sized so that the Fs wouldn´t drop .. or as low a possible.
The passive filter network which is inherent to a original Ripole design sinks the driver´s Fs considerably.
The Linkwitz design doesn´t use this filter network, but only active filtering, which doesn´t sink the Fs.
If Your Buddy still insists on a true Ripole design, I can only recommend out of bad experience to withdraw from that project and save Your good reputation.
In the end You might end up being made responsible for the fail or suboptimal outcome.
If people insist on making failures against sound advice let them make the failures ... but their´s not Your´s.
jauu
Calvin
I stand opposed to adding uncoupled dead weight to a cone as means
of lowering Fs. Weight of air column short circuit that does not couple
to the room and unloads the lower frequencies to no good end.
But if you are dead set to watch cones flap uselessly and make a lot of
air rushing noise instead of bass, get the most XMAX and XLIM you can.
Cone bottoming out will sound even worse, and then you have lost any
option of re-purposing those drivers to a real cabinet in the future. Folly
on top of folly, to Ripole expensive pro woofers of such limited excursion.
Take a look at Delta 15FL-4, cheaper than either of your listed choices.
6MM XMAX, and w bumped plate we can hope perhaps far greater XLIM.
Pair of 4ohm in series is same impedance as a pair of 16 in parallel...
Qts in the Zone Calvin was recommending will rise with dead weight,
I would assume ending with 0.6 to 0.9 Qts along with lowered Fs as
the wishful thinking behind it? Also the moving mass is only 66g,
which gives the added air weight more influence.
Even with a modest bump, might not be enough XLIM for Ripole.
There may be car audio junk drivers that would surpass any pro
driver in surviving this particularly absurd specialized application.
of lowering Fs. Weight of air column short circuit that does not couple
to the room and unloads the lower frequencies to no good end.
But if you are dead set to watch cones flap uselessly and make a lot of
air rushing noise instead of bass, get the most XMAX and XLIM you can.
Cone bottoming out will sound even worse, and then you have lost any
option of re-purposing those drivers to a real cabinet in the future. Folly
on top of folly, to Ripole expensive pro woofers of such limited excursion.
Take a look at Delta 15FL-4, cheaper than either of your listed choices.
6MM XMAX, and w bumped plate we can hope perhaps far greater XLIM.
Pair of 4ohm in series is same impedance as a pair of 16 in parallel...
Qts in the Zone Calvin was recommending will rise with dead weight,
I would assume ending with 0.6 to 0.9 Qts along with lowered Fs as
the wishful thinking behind it? Also the moving mass is only 66g,
which gives the added air weight more influence.
Even with a modest bump, might not be enough XLIM for Ripole.
There may be car audio junk drivers that would surpass any pro
driver in surviving this particularly absurd specialized application.
Last edited:
Assumed because 16ohm, he was already planning a pair.
Good you made clearer the mechanical necessity. Going to
shake like hell otherwise. Lots of flapping, not much bass...
You might want to flip one driver of the above pair for the
distortion cancellation as you mentioned. These will travel
the full excursion and all non-linearity thereof.
To correct my typo in #13, should have read: Delta15 LF-4.
Good you made clearer the mechanical necessity. Going to
shake like hell otherwise. Lots of flapping, not much bass...
You might want to flip one driver of the above pair for the
distortion cancellation as you mentioned. These will travel
the full excursion and all non-linearity thereof.
To correct my typo in #13, should have read: Delta15 LF-4.
Last edited:
As the world's leading authority on "how not to build a ripole", I feel compelled to add a link that demonstrates the effect the cavity has on Qts and Fs
http://www.diyaudio.com/forums/subw...but-these-drivers-suitable-6.html#post4085513
Also, Using a cone to magnet arrangement reduces even order harmonic distortion, but also makes the arrangement less symmetric in terms on the air cavity load on the individual drivers, .. for whatever that's worth. The cone - cone arrangement is how the ripole was intended to "work" i.e. the "blow motion principle"
Hi,
No. It is simply not any form of air motion transformer.
That would be a horn. Farfield SPL is directly related
to cone excursion and baffle loss. The only exception
is the resonant lengths of the ripole chambers, which
of course you should be rolling off below to avoid.
rgds, sreten.
- Status
- This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.