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Old 20th January 2010, 08:54 PM   #191
Ciu is offline Ciu  France
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Hello Rudolf !
Thanks for this simulation, now I have a more precise idea what to do with. May be this would help somebody else, the Audax Pr300T0 bought from Ebay Belgium last year...

Greatfull Thanks!
Richard
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Old 18th January 2011, 02:30 AM   #192
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Hi all.

I've started my Ripole subs project using (4) Peerless SLS 12's and boxes will consist of 19mm MDF + 5mm oak plywood glued on. At this time I have the panels cut to initial oversize and the plywood glued on. Now I need a sanity check and some advice on the best choice between the (3) versions I'm considering. I'm not well versed on ripole design but I'm using Rudolf's generic guidelines for reference.

View my sketches here:
Jazzman's DIY Electrostatic Loudspeaker Page: Ripole subs are underway

I rather like the looks of the ultra-compact design of version 2, which has the woofer magnet ring flush to the box sides. However, the rear chamber is less than 1/2 SD. Before I dismiss this version I would like to understand what effect the lesser rear chamber area would have.

Version 1 likewise has the motor magnet ring flush to the side panels and similar width but achieves 1/2 SD on the rear openings by increased cabinet height.

Version 3 has only the very tip of the motor flush to the box sides and achieves 1/2 SD by increased cabinet width.

Your critiques, comments and suggested changes will be greatly appreciated, as I can't continue until I can nail down a design!

thanks all!
Charlie

Last edited by CharlieM; 18th January 2011 at 02:42 AM.
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Old 18th January 2011, 08:08 AM   #193
Calvin is offline Calvin  Germany
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Hi,

for the Peerless Id choose the larger version. Even then the Fb sinks below 20Hz. With the smaller versions the Fb drops below 16Hz, which is of no use in a dipole. And dont forget to add the passive equing network

jauuu
Calvin
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Old 18th January 2011, 10:34 PM   #194
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Thanks Calvin,
More Questions:

1) To make the box larger I assume we are talking about the area of the openings, so does it matter whether it's the width or the height that's increased?

2) Is there an advantage or penalty to adding 45 degree corner baffles at the rear of the center box chamber, as shown in this photo:
http://www.rstaudio.de/Subwoofer/Lasur.jpg

I'm sure I will have more questions concerning a passive EQ (low pass LRC filter?) and a crossover slope when I get to that point. I will be wiring the woofers parallel and using an active crossover and dedicated power amp.

Charlie
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Old 21st January 2011, 12:39 PM   #195
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Quote:
Originally Posted by Calvin View Post
Hi,

for the Peerless Id choose the larger version. Even then the Fb sinks below 20Hz. With the smaller versions the Fb drops below 16Hz, which is of no use in a dipole. And dont forget to add the passive equing network

jauuu
Calvin
I'm not at all clear on the passive EQ reqirements for the ripoles. I'm guessing it would be first order shelving circuit with components geared to a center frequency and woofers' impedance? Also, I've read some posts that suggest a notch filter for the charactristic ripole pipe resonance between 200-300hz-- can this be combined with the EQ filter? Or do I even need to worry about the pipe resonance if I cross over low enough with a steep slope?

I will be buying an active crossover for this project (slope undetermined at this time) and I also have a Behriger DEQ 2496 for line level EQ'ing upstream of the power amps. Even so, I've read some posts that recommend passive rather than active EQ'ing for ripoles so I'm thinking that's the way to go. Again, I seem to be stuck on stupid here with respect to ripole characteristics and EQ'ing. I need some help.

Last edited by CharlieM; 21st January 2011 at 12:59 PM.
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Old 24th February 2014, 07:26 PM   #196
satx is offline satx  United States
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Hey, I know this is an old thread, but I didn't want to start a new thread just for my question. I hope someone can help me without too much trouble.

So... I am working on the preliminary stages of a design for a 3 way dipole using a stacked Ripole as the woofer section, but I'm having trouble understanding what kind of usable bass I will achieve given number of drivers, driver size and xmax. SL's dipole spl spreadsheet is giving me pretty low numbers and I don't know if it's even applicable for Ripole.

I'm shooting for a target response of max/105db with an F3/30Hz, highpassed at 30Hz.
I don't listen at those volumes, but I do crank it occasionally and sometimes somebody besides me will get a hold of my system. I don't want it to bottom easily. Also, I will likely use them with my subs(sealed RSS390HF's) crossed at around 40-50Hz most of the time, but I want them to be able to stand on their own to 30Hz.

My plan is a stacked Ripole using 10-12" drivers(4) with 5-7mm xmax each in a traditional Ripole configuration. They will be low passed between 100-150Hz. I'll be using a 250Wx2@4ohms class D amp and minidsp. I know the excursion is low, but that would equal two 10-12" woofers with 10-14mm in a single Ripole.

I'd love to use the 10" drivers with 5mm xmax as they would allow the smallest footprint, hence they will have the highest quarter wave resonance and slimmest baffle/best dipole response @ the xo. And they're the cheapest

Will these be enough to hit my target spl and f3? That's about 7000 cm^2 of displacement for the 5mm ten inch drivers.

If not those tens, will any of these drivers in stereo groups of frour be able to reach my targets in a Ripole?

Thanks for the help!

Evan
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Old 24th February 2014, 10:25 PM   #197
satx is offline satx  United States
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Okay, so I thought I had read just about all I could on BMC's or Ripoles in English. I just found this post by Calvin that says that a properly designed pair of ripoles (4 drivers) will roughly equal the spl of 1 of the same driver sealed. That is excursion limited spl.

The spl of the single 10" woofer mentioned above is only 92.5db@30Hz so I guess I'm not likely to hit 105db with any of these drivers. This is using unibox to calculate.

One thing that is confusing me is the effect of gain from the floor, gain from a stereo pair and I think I read another 3db of gain somewhere. Going by those numbers it looks like I could reach 117db @ 1 meter, but that sounds really optimistic.

Can anyone shed a little more light on how to calculate and add the effects of these different things to a simulators results?

Thanks
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Old 24th February 2014, 11:15 PM   #198
puppet is offline puppet  United States
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You might consider positioning the ripole closer to the listening area.
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Old 24th February 2014, 11:27 PM   #199
satx is offline satx  United States
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Quote:
Originally Posted by puppet View Post
You might consider positioning the ripole closer to the listening area.
Thanks

I've read the posts of people doing that and that would certainly help, but as I said, this is for the bottom of a three way crossed around 100-150


Also, I already have good subs so I'm not trying to use the Ripoles as subs, but as woofers
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Old 25th February 2014, 12:52 AM   #200
puppet is offline puppet  United States
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Gotcha ... I wouldn't bother with the ripole for the woofer section myself. Seems like it would color the start of the voice frequencies too much ... if h/u frames are any judge in the ranges above 150hz. Aren't ripoles strong point the extended Fs of a given driver? What is your reasoning for using it as a midbass enclosure?
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