Hi
I do not mean a gitar speaker. but with stiff I mean not a rubber suspension but a harmonica like one like as with the BMS speakers, I have on this moment contact with a chinese factory for make special ones for ob and dipoles/ripoles, maybe it is a good bussiness if there are people who wil buy that, I try afcourse for not expensive ones.
I have two visatons wsp26s in the dipole, and it has 22mm xmax 330cm2 for a 10 inch, that is big but it have a soft suspension and I still think we need some more rigid for dipoles with 12 mm xmax 18 inch.
thanks.
I do not mean a gitar speaker. but with stiff I mean not a rubber suspension but a harmonica like one like as with the BMS speakers, I have on this moment contact with a chinese factory for make special ones for ob and dipoles/ripoles, maybe it is a good bussiness if there are people who wil buy that, I try afcourse for not expensive ones.
I have two visatons wsp26s in the dipole, and it has 22mm xmax 330cm2 for a 10 inch, that is big but it have a soft suspension and I still think we need some more rigid for dipoles with 12 mm xmax 18 inch.
thanks.
Hello, at some stage it got said that the Ripole is only 25% efficient, compared to a closed box or a bass-reflex. Now come a few stupid questions.
1. Say you complete a Ripole made of two woofers, each featuring a 96 dB/Watt efficiency. Put 1 Watt of power at 50 Hz. What's the dB SPL?
2. Say you just completed a bass-reflex (or closed box) containing the same two woofers. Put 1 Watt of power at 50 Hz. What's the dB SPL?
3. Thus, how many dB SPL in global efficiency get wasted by the acoustic short-circuit occurring inside the Ripole?
4. Thus, it is feasible to design a conventional bass-reflex tuned around 50 Hz, quite compact (albeit not as compact as the Ripole, maybe), delivering about the same deep bass extension and about the same global dB/watt sensitivity?
5. Don't you have the intuition that this will be feasible, and cheaper than the twin-woofer Ripole?
1. Say you complete a Ripole made of two woofers, each featuring a 96 dB/Watt efficiency. Put 1 Watt of power at 50 Hz. What's the dB SPL?
2. Say you just completed a bass-reflex (or closed box) containing the same two woofers. Put 1 Watt of power at 50 Hz. What's the dB SPL?
3. Thus, how many dB SPL in global efficiency get wasted by the acoustic short-circuit occurring inside the Ripole?
4. Thus, it is feasible to design a conventional bass-reflex tuned around 50 Hz, quite compact (albeit not as compact as the Ripole, maybe), delivering about the same deep bass extension and about the same global dB/watt sensitivity?
5. Don't you have the intuition that this will be feasible, and cheaper than the twin-woofer Ripole?
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I think it was me who posted that my Ripoles are only about 25% as effiecient as conventional subs. While I believe this is essentially true for the lowest frequencies, my statement was misleading. I think Calvin's insight and explanation was much better than mine, so I will quote him here:
"Efficiency is often misunderstood or used in an incorrect way. As a follow Dipoles are said to have low efficiency. But that is not the whole case.
The dipole does not exite the room below the lowest room mode as a global distributing bass would, so it doesn´t profit from the room gain. It also suffers from acoustic phase cancellation. So one would truely expect less SPL at very low frequencies.
But if one compares efficiencies one needs to keep in mind the circumstances. A dipole benefits from the SPL of its backside. So above a certain frequency break point the dipole surpasses CB- and BR-loaded boxes. For typical subwoofer dimensions this break point is located somewhere between 50Hz and 80Hz. So if You´re using the dipole only as bass, keeping it off of the subwoofer-range below 50Hz it plays on par with CBs and BRs.
What else is usually not taken into account is the size of the dipole. A CB or BR (if a BR of such small size would be possible anyhow) of same size and under usage of a same sized driver would need heavy equalization and would yield a low efficiency also. You can trade size against efficiency. So a smaller sized system must be lower in efficiency.
If I compare a dipole of a size that may even be smaller than the drivers shipping cartonage, I need to compare it against a CB or BR of equal size."
I can't answer your other questions either, but if high efficiency is a priority, perhaps monopoles would be a better choice.
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Hi
Steph have You read and understood #25??
It explains the difficulties in evaluating the true efficiency and even more so comparing two efficiencies.
What do You want to compare if there are different ....
- drivers
- alignments
- amplitude responses (especially farfield)
- dimensions
- electronic equalizations
???????
Its like comparing apples and pineapples.
Due to different room interaction even equalized-to-same-amplitude-response-in nearfield the dipole will measure and sound different in the farfield to a monopole.
What remains is that the dipole requires large amounts of membrane area and that especially the small sized Ripoles allow for up to 4-times the membrane area as a similar sized casing in CB or BR.
It is a huge difference in saying ´25% efficiency´ or ´up to 4-times membrane area in similar sized casing´.
jauu
Calvin
Not Your Qs are stupid, but the above statement.
Steph have You read and understood #25??
It explains the difficulties in evaluating the true efficiency and even more so comparing two efficiencies.
What do You want to compare if there are different ....
- drivers
- alignments
- amplitude responses (especially farfield)
- dimensions
- electronic equalizations
???????
Its like comparing apples and pineapples.
Due to different room interaction even equalized-to-same-amplitude-response-in nearfield the dipole will measure and sound different in the farfield to a monopole.
What remains is that the dipole requires large amounts of membrane area and that especially the small sized Ripoles allow for up to 4-times the membrane area as a similar sized casing in CB or BR.
It is a huge difference in saying ´25% efficiency´ or ´up to 4-times membrane area in similar sized casing´.
As most Dipoles require rather more than less electronic equalization, the final amplitude response will be mainly shaped by the EQ and room and surroundings.
If You want good results choose the driver after the requirements. There are drivers that may suit both, the Dipole as well as a CB, but optimum drivers will certainly feature different sets of parameters.
jauu
Calvin
Not only I've never mentioned any kind of electronic equalization, but also you appear to react like I'm ignoring or disagreeing about the on-axis, 90 degree off-axis, near field and far field amplitude response presumable differences.
After your vast knowledge getting exposed, after reading in detail your #8, #10, #17, #20, #27 posts, why don't you deliver a set of amplitude response curves, all plotted on a same graph, so we can compare them?
About the near field and far field features, why don't you deliver a set of amplitude response curves, all plotted on a same graph, measured from different locations (and/or in various room sizes), so we can compare them?
Why don't you deliver more substantial subjective listening descriptions, about "omidirectional bass" perception against "shaking bass" perception. Is this before or after electronic equalization ? Is this near field or far field ? Is this Ripole against closed box, against bass-reflex, or against port-only outputs like the 4th-order bandpass, 7th-order bandpass, or 8th-order bandpass ?
All the time taken in discussing unverifiable features (or issues, it depends how you read) would have got a better allocation in building a closed box using the same speaker driver(s), measuring it and plotting it along with the various Ripole curves, enabling objective and verifiable comparisons.
You appear to neglect that the diyAudio audience is mature and skilled enough for assessing a design, even if it may exhibit a complicated amplitude response in bare state, without any kind of coil filtering and/or electronic equalization. Cheers!
1m ground plane comparison of sealed, H, N, & Ripole using same woofer posted here:
http://www.diyaudio.com/forums/plan...le-cavity-resonance-question.html#post3582579
Note that the plot is a comparison of sensitivity (ie SPL out for the same voltage input).
Thanks bolserst, very nice post. One graph with 4 curves is worth 1,000 words.
Ripole style with a 3 inch cavity exhibits the most compact shape, however the price to pay is a 9 dB sensitivity loss. At first glance such 9 dB waste looks fatal. Looking further, one realize that with adequate electronic equalization, one may approach a 1st-order highpass transfer function extending from 20 Hz to 120 Hz. After 15 minutes listening, your auditory system will compensate the 1st-order slope. Listening a full week on a daily base, it you happen to listen to other systems featuring the usual 2nd-order highpass slope (closed box) or 4th-order highpass slope (bass-reflex) at 40 Hz or so, you'll maybe realize how they sound defective.
Now, don't take this for granted. The 120 Hz crossover between the Ripole and the midbass must be properly done, without any relative phase shift between the two outputs. That's not easy to get. A prerequisite is to rely on a 2-channel audio analyzer, able to plot the phase (channel 1 used reference). If this is not done properly, there will be a serious issue around 120 Hz, ruining all efforts.
Ripole style with a 3 inch cavity exhibits the most compact shape, however the price to pay is a 9 dB sensitivity loss. At first glance such 9 dB waste looks fatal. Looking further, one realize that with adequate electronic equalization, one may approach a 1st-order highpass transfer function extending from 20 Hz to 120 Hz. After 15 minutes listening, your auditory system will compensate the 1st-order slope. Listening a full week on a daily base, it you happen to listen to other systems featuring the usual 2nd-order highpass slope (closed box) or 4th-order highpass slope (bass-reflex) at 40 Hz or so, you'll maybe realize how they sound defective.
Now, don't take this for granted. The 120 Hz crossover between the Ripole and the midbass must be properly done, without any relative phase shift between the two outputs. That's not easy to get. A prerequisite is to rely on a 2-channel audio analyzer, able to plot the phase (channel 1 used reference). If this is not done properly, there will be a serious issue around 120 Hz, ruining all efforts.
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Hi,
OffT
@steph_tsf
putting parts of cites of another person together in a form that implies a totally different meaning is certainly bad style.
Putting them together that it implies an unfriendly, even rude behaviour of the cited person, is a plain affront and impertinence.
I´ll report to the admins.
Also, if You want someone else to help You, You might choose a less postulating, commanding tongue.
Certainly, no one is here to do measurements on Your demand or command or anybody else´s.
OnT
jauu
Calvin
OffT
@steph_tsf
putting parts of cites of another person together in a form that implies a totally different meaning is certainly bad style.
Putting them together that it implies an unfriendly, even rude behaviour of the cited person, is a plain affront and impertinence.
I´ll report to the admins.
Also, if You want someone else to help You, You might choose a less postulating, commanding tongue.
Certainly, no one is here to do measurements on Your demand or command or anybody else´s.
OnT
jauu
Calvin
Before I get banned from diyAudio (thanks Calvin), I feel I need to tell that equalizing a woofer between 20 Hz and 120 Hz may fail using a digital equalizer based on a DSP56K processor (24 bit audio and intermediate storage on 24 bits), because of the internal gain featured by the IIR resonating cells. A digital equalizer operating on 32 bit audio, with intermediate storage on 32 bit, is mandatory.
During the experimental stage, I strongly advise to use a personal computer running Windows XP as equalizer and crossover, dealing with 32 bit audio. Try Flowstone. it costs nothing (trial version) and flexibility is king.
If you prefer analog, you can rub out the few peaks using active filters relying on (huge) synthesized coils using gyrators, say three parametric Eq in series dedicated to the 20 Hz to 120 Hz frequency band, plus three other parametric Eq rubbing some the high frequency peaks, plus a dedicated lowpass filter for targeting a acoustic Linkwitz-Riley 4th-order lowpass after 120 Hz. I'm afraid the transistor count in analog domain will repel most audiophiles.
Having said this, I'm curious to see the phase curve of a properly equalized Ripole. Will it reduce to the theoretical +90 degree of a 1st-order highpass system, or will there be a lot of "excessive phase" ?
During the experimental stage, I strongly advise to use a personal computer running Windows XP as equalizer and crossover, dealing with 32 bit audio. Try Flowstone. it costs nothing (trial version) and flexibility is king.
If you prefer analog, you can rub out the few peaks using active filters relying on (huge) synthesized coils using gyrators, say three parametric Eq in series dedicated to the 20 Hz to 120 Hz frequency band, plus three other parametric Eq rubbing some the high frequency peaks, plus a dedicated lowpass filter for targeting a acoustic Linkwitz-Riley 4th-order lowpass after 120 Hz. I'm afraid the transistor count in analog domain will repel most audiophiles.
Having said this, I'm curious to see the phase curve of a properly equalized Ripole. Will it reduce to the theoretical +90 degree of a 1st-order highpass system, or will there be a lot of "excessive phase" ?
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Hi, Not Your Qs are stupid, but the above statement.
What do You want to compare if there are different ....
- drivers
- alignments
- amplitude responses (especially farfield)
- dimensions
- electronic equalizations
???????
Its like comparing apples and pineapples.
Due to different room interaction even equalized-to-same-amplitude-response-in nearfield the dipole will measure and sound different in the farfield to a monopole.
What remains is that the dipole requires large amounts of membrane area and that especially the small sized Ripoles allow for up to 4-times the membrane area as a similar sized casing in CB or BR.
It is a huge difference in saying ´25% efficiency´ or ´up to 4-times membrane area in similar sized casing´.
As most Dipoles require rather more than less electronic equalization, the final amplitude response will be mainly shaped by the EQ and room and surroundings.
If You want good results choose the driver after the requirements. There are drivers that may suit both, the Dipole as well as a CB, but optimum drivers will certainly feature different sets of parameters.
jauu
Calvin
I'm deeply sorry, I totally disagree about the 20 points infraction you managed to prejudice me. As the above full quote clearly shows, you wrote "stupid", preceded by a negation "not", a negation that gets tempered by the "but" that's immediately following. Now look your main conclusion : "it's like comparing apples and pineapples". If I deserve a 20 points penalty for resolving your double negation to a plain unjustified aggression against me, you deserve a 40 points penalty for viciously hiding your aggression behind purpose-made, elaborate double negations. Please stop this.
It wil not go loud because ripoles need cone surface, like 15 inchers for some serious bass. You can stack multiply tough.
I no she has advances like room modes are less important, more low.
This one is a lot better, seems to sound very well but need distance from wall.
vrg kees
Besides the obvious beaming that will occur, the midrange and treble are rough.
For bass duty alone, it may be fine. IME, you may be surprised how quickly a pair of 12's or even 15's can run out of steam in this configuration.
Sent from my SM-G920V using Tapatalk
it it a good idea to use a pair of car subwoofer of Qts of 0.7, Fs of around 25hz and sensitivity of 95dB in ripole? this will handle freq only upto 100-120hz or so and will be crossed to a full range driver after. my SPL requirement is not more than 90db. room is pretty small (around 12' x 16')
You're not going to find a woofer with that high of a sensitivity with those specs.
The best budget woofer I've found is the JBL GT5-15.
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