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Query related to Ripole woofer setup

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Sumanta

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Dear all,
I am going for a Ripole woofer setup for my open baffle speaker.
I will be making a single driver Ripole design.

I want to know, what should be port opening ratio for single driver cabinet construction. My study in net says for XMax <10mm, 1/4 Sd for front and 1/2 to 1 Sd for rear port for two driver construction.

My common sense says it should be 1/4 Sd for both port for single driver case.
Inspite of several search. I could not find any write-up, sharing of experience related to single driver case.

Please direct me to a knowledge based answer if anyone know something.

thanks,
Sumanta
 

goldyrathore

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A dipole (or ripole) does not make sense below the room Schroeder frequency. There are no room modes so a monopole (sealed/ported/PR) is better in every respect.
 
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Sumanta

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A dipole (or ripole) does not make sense below the room Schroeder frequency. There are no room modes so a monopole (sealed/ported/PR) is better in every respect.

But my current dipole plays much more accurate bass than the ported woofer of my FS speakers in my listening room!!!

I like dipole bass much more than cabinet bass.

Let's talk about Ripol N design requirement please.
 

Sumanta

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Off the topic but interesting and important to me, thanks to Goldyrathore.
A dipole (or ripole) does not make sense below the room Schroeder frequency. There are no room modes so a monopole (sealed/ported/PR) is better in every respect.

Dear Goldyrathore,
Thanks for bringing Schroeder frequency to my notice. I have quickly read to understand its basics.
In the mean time understood benefit of dipole speakers over monopole in the following link and get more clarity on why I perceive clearer bass in my dipole than my monopoles. Chapter c in specific of the link to be read, Schroeder frequency is explained here too for people like me.

Room Acoustics
 

Sumanta

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114 views yet no positive input to my query.

Seems Ripole is not so popular in us. Its not much different in worldwide as well. Probably because of limiting calculating software.
 

goldyrathore

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Probably because Ripole is highly inefficient, more difficult to get it right and needs more drivers/power for the same target SPL. Sonically there is no advantage below the first room mode. Even in the modal region (between first mode and Schroeder freq) the measured bass is not flat and requires EQ just like any other dipole.
 

Sumanta

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Probably because Ripole is highly inefficient, more difficult to get it right and needs more drivers/power for the same target SPL. Sonically there is no advantage below the first room mode. Even in the modal region (between first mode and Schroeder freq) the measured bass is not flat and requires EQ just like any other dipole.

I think you are wrong as far as those who made Ripole saying they are very happy are true statements.
 

Fantastic

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Not quite sure how loud you play your music. Ripoles are inefficient but can go deeper than other dipoles. You also need lots of cone surface area to achieve loud levels at LF. Eq will also be high and so drivers need to have high power handling capacity most of which is lost in equalisation ! But they are smaller than other solutions. You can also stack them up for higher power levels. Not to mention large power amps for each. I guess your driver is at least a 15 inch unit.

You might find that lots of people prefer the sound of the H frame followed by the U frame. But you should make what you prefer since none of them are ideal systems and so there is no 'best' solution.
 

Sumanta

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Dear Fantastic,
Thanks for trying to help me.
I have heard (personally) bass from plain OB and H frame OB and that is why will go for OB bass only. I have not yet heard Ripole and reading other's recommendation, I am interested to make a Ripole suitable for my requirement. Afterall Ripole is a folded pressurized open baffle only.
I know all the requirements that you said, but am looking for a particular answer to a particular question mentioned above.

It will be good if I get answer to that, or else will go by my ear and logic and my limited knowledge on sound and of course with the help from cautiously selected internet information.
 

Fantastic

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Most 'suggestions' cover a range and it appears to be related to the air mass load on the respective surfaces of the driver. I think the differential may be to off set the resonances that they cause and thus widen the flat response region.

People have successfully built the ripole with a front to rear area ratio of 1:2 with two drivers. But if you think for a moment increasing the drivers increases the surface area . So if you use one driver you can use 1/2 the area and keep the original rear area used on one driver. So the ratio still is 1:2 !
Drivers with approx more than 10mm will move much more air and so they recommend larger frontal area. Not sure if it is to reduce air velocity or due to linearity reasons.

I think you should build a 'box' with the driver . Make the 'spacer' and front end separate and just bolted on. That way you can change the spacer and try out different frontal areas. Start with a 1:2 ratio that others have tried.
Hope you have some measurement equipment. Even an inexpensive set up should be OK. This will be helpful more for making relative measurements and not absolute ones.
All the best.
 

Sumanta

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People have successfully built the ripole with a front to rear area ratio of 1:2 with two drivers. But if you think for a moment increasing the drivers increases the surface area . So if you use one driver you can use 1/2 the area and keep the original rear area used on one driver. So the ratio still is 1:2 !
All the best.

People have used 1/3rd to 1/4 for front and 1/2 to 1 for rear with two drivers. Definitely net sum of 2 Sd governed there. In my case it is just 1 Sd.

I think it should be 1/4 Sd for both front and rear port for single speaker as it was pointed out in diyaudio site (forgot the page). But box space should be compensated for the cone shape, back space should be wider than front.

I do not use measurement (yet) except my ear.
I had thought of going bolted way, but was not sure whether really will I re work on those boxes once it fails my ears. Plus, getting those suitable bolts are a pain. Rather keeping possibilities to change port size is a better option as the secret is there.

Longer Xmax is required to increase volume handled by drivers to increase SPL as Ripole is inefficient. Here but, I am not much bothered as I will use 15 inch drivers and they already have proved their performance in my present OB. In comparison to my present 12 inch mid driver, I will be using an 8 inch driver with 4 dB less SPL than the current 12 inch driver.

With Ripole I am trying to utilize a so called full ranger to the max and supporting it only at the low frequencies. My earlier intention was to cross at 250 Hz but am now worried about cabinet resonance. Let's see when can I get a carpenter to start:sad:.

Just an OT, Omni speakers are quite good and quite close in performance to OB as it was compared and explained by Riley with his Orion and Pluto. I can confirm now having an OB and something similar to Pluto.
 

Sumanta

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I had made a Ripole speaker. It is in painting process. Will post pictures soon.
I am making a OB for mid and upper frequencies. I will try active cross over through Foobar with Creative's DSP to find the appropriate cross over point and type for the Ripole and mid/tweeter set up.
Let's hope for the best.
 

Sumanta

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OB for mid and top and Ripole OB for low combination is now singing fine at my listening room.
Still there are work to do related to speaker cover grill and lug pins.

Here are photos of them.






 

Sumanta

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First impression:

I am happy with Ripole design. It worked the way I thought it will. I am getting lower frequencies better than my last OB. Fs of the 15 inch has reduced considerably. Overall design is compact than the last one. difference of around 9 SPL between 8 inch and 15 inch driver worked well for OB and Ripole OB system.

Philips 48002 is a nice driver. As Anthony wrote, it gives quite realistic voice reproduction. I still like mid from the 12FRX of Ahuja a little bit more for overall meatier presence, but these Philips drivers are in short good.

What impressed me the most now in this set up is spatial presentation. I am going through several tests to find if Ahuja Xover will work for this set up. The target is to make my system independent of active cross over. Because ultimately I want to play my record player with this speaker. At present I can not as they are active and controlled by laptop (foobar) and Creative's soundblaster DSP combination.
 

soundnovice

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i am not sure at bass freq below 300hz you will have any special advantage of going ripole or dipole....means bass will sound same in sealed or ripole or dipole at this low...but dipole will have better room interaction of course. i have not read anywhere ripole offers good handling of room modes, but dipole is for sure. especially in H-frame. i personally agree with goldy that a sealed sub can be lot more pocket friendly, small, good room interaction and nicely matches to main speakers being extremely simple to design and construct and tune! plus if u have high xmax drivers, you can add linkwitz transform to extend Fs to as close as 20hz (if enough xmax and power handling capability is available).....achieving the same with ripole or dipole could be costly affair. if ur crossing below 100hz.....then i strongly believe anything other than sealed hardly makes any sense.
 

Fantastic

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Dipole bass sounds different from boxed speakers. The Ripole is just a dipole configured a bit differently. Ripole stands for Rithalder's dipole , if I am not mistaken .
 

Sumanta

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Dipole bass sounds different from boxed speakers. The Ripole is just a dipole configured a bit differently. Ripole stands for Rithalder's dipole , if I am not mistaken .

Right, his name is Axel Ridtahler.
 

Sumanta

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i am not sure at bass freq below 300hz you will have any special advantage of going ripole or dipole....means bass will sound same in sealed or ripole or dipole at this low...but dipole will have better room interaction of course.

I remember you said you heard OB sound of LX521 Linkwitz Riley. One of the key difference between OBs and cabinet speakers is the clear bass. Clear bass is something an OB fan dies for and so can never go back to a cabinet speaker with happy ears. Yes dipole subs do not thump chest but sounds true. Musical.

i have not read anywhere ripole offers good handling of room modes, but dipole is for sure. especially in H-frame..

Ripole is just a folded dipole and yes it has less room interaction. It has benefits of dipole and compactness of cabinet speakers.
It worked right for me as I had main speakers of much lesser SPL hence low effectiveness of Ripole didn't affect overall sound quality. Having dedicated amplifier for different drivers, I have extensive freedom as well.

i personally agree with goldy that a sealed sub can be lot more pocket friendly, small, good room interaction and nicely matches to main speakers being extremely simple to design and construct and tune! plus if u have high xmax drivers, you can add linkwitz transform to extend Fs to as close as 20hz (if enough xmax and power handling capability is available).....achieving the same with ripole or dipole could be costly affair. if ur crossing below 100hz.....then i strongly believe anything other than sealed hardly makes any sense.

I wish you could hear a Ripole. Well, Ripole is pocket friendly, more compact than a sub having same driver, has low room interaction being dipole, simpler to design than a sub (to me atleast).
Ripole Fs of a driver which is the key reason for me to go for it as I wanted to use my existing drivers with better efficiencies at lower frequencies. It's design Fs is 45 Hz. Now it is playing lower frequencies better with effective Fs being somewhere around 35 Hz. Costing is my second key measurement scale for my success.

I do not much care about frequencies lower than 40 Hz. 20 Hz sound I probably can not hear now with my age crossed 40. And I know there are not many instrument out there in music I listen which play these low frequencies.

As I said earlier as well, I listen to music, not sound reproduction. I initially check my system with sound reproduction and then enjoy music. At present I am checking my system with my ear and my set of selected sound sources in CDs and with real instruments. My goal is to get rid of laptop based cross over so that I can hear my records through this speaker system.

Very soon, I will start enjoying music more than I was with my present set of speakers.

And I am slowly getting convinced that right brain can visualize a sound so much that it actually can enjoy it same whether it listens through a tiny low quality speaker or a good quality aptly designed one. It is like a child, easy to convince.
Left mind brings in problem by defining music with frequencies.

My goal is to enjoy music through the shortest, easiest and cheapest way. Minimum qualities for enjoyment is still controlled by my left brain and soon it will be satisfied.
 

soundnovice

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dipole would sound best of course....provided you put in thousands of dollors and construct a dual sub stereo dipole in h-frame!
anything else would never sounds true bass. my opinion.
i realized few things about rooms in US compared to our room setup. the walls are by default made of wood. and most of time walls have fibre glass as the heaters are built into the walls. then the floor carpet. so by default room is well designed for better acoustics. now compare the same to our rooms! solid reflective marble floors. non-absorptive walls. etc. so in my opinion a sealed box sitting in a corner or multiple sealed subs in each of the corner of the room with the reflective surfaces close to them...would actually produce better bass. ofcourse a dipole dual sub push pull would sound better but at a huge cost....

and almost nobody can hear anything at 20hz. that frequency range is supposed to be felt. only the one who have 'felt' it would understand....for others ignorance is bliss! i belive strongly that if during recording there is music content at 20hz then reproducing and hearing/feeling it will complete the quest for audiophile music and tremendous fun of listening to music. you can appreciate Zakir's true geniousness when you hear the lower octaves that his beats produce.....ofcourse achieving that is the true challenge. so pls dont limit yourself to 40hz! it is possible to reach 20hz and try to do that. meanwhile keep enjoying the music....
 
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