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Old 15th September 2007, 05:33 PM   #21
zobsky is offline zobsky  India
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Quote:
Originally posted by johninCR



With all 4 in 1 cab, just space efficiency, since 2 cone to cone and 2 magnet to magnet would still be push-pull. With only 4 drivers I'd suggest 2 cabs for maximum flexibility in placement, in which case cone to magnet is required for push-pull. Also, I find stereo into the bottom octave more important with open alignments even if the signal is mono.



Same as a W, but flatter bottom end, just as discussed in the original ripole thread. ie EQ may not be needed.


Yes, ... the reason I've bought 4 drivers is to build 2 cabinets, a pair to each. Each cabinet will POSSIBLY (or not) serve as a stand for the main speaker , depending on how they perform at that position (approximately 1m from rear and 0.5 m from side walls)
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Old 15th September 2007, 07:56 PM   #22
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Mine will also serve as the bottom portion of my speakers. The top will have a 10" driver fo the midbass/mids and then Heil AMT for the mid/highs.

Man, I really need to find someone local to cut some wood for me. I'm limited to what a jigsaw can do in an apartment.

Chops, your not going crazy; a ripole IS just a N/W baffle with restricted openings.
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Old 15th September 2007, 11:37 PM   #23
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Zobsky,

There's a catch with 2 drivers per cab, and that is how are you going to get equal loading if you do it in a W alignment to get the vibration cancellation too? That's the main reason I went with 4 in each cab, to get everything including the symmetry required for the Ripole concept.


Chops,

Yes, the original ripole is a double driver "N". I give credit where I think it's due by calling mine Ripole hybrids, since I'm trying to take advantage of the restricted pathway to mass load the driver for flatter extension down low.
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Old 16th September 2007, 12:15 AM   #24
y8s is offline y8s  United States
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I have 4 of the Stryke AV15 woofers that I originally bought intending to use as the woofer modules for some Linkwitz Phoenix speakers.

I may try to re-build their W baffles into a ripole config.

I googled a bit to find the parameters of a ripole. it found a post by johninCR saying you make the openings 25-30% of the driver's Sd.

Specs on the AV15:
Fs: 19.7 Hz
Qms: 4.71
Qes: .399
Qts: .368
Vas: 228 L
Re: 2.97 ohm
Z: 4 ohm
(dual 2 ohm)
BL: 15.5 Tm
Cms: .25 mm/N
Mms: 260 g
Pe: 500W
1W/1m: 88.5dB
2.83V: 92.5dB
Xmax: 23 mm
Xsus: 30 mm
Sd: 802 sq cm
Vd: 3.8 L
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Old 16th September 2007, 01:46 AM   #25
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Quote:
Originally posted by y8s
I have 4 of the Stryke AV15 woofers that I originally bought intending to use as the woofer modules for some Linkwitz Phoenix speakers.

I may try to re-build their W baffles into a ripole config.

I googled a bit to find the parameters of a ripole. it found a post by johninCR saying you make the openings 25-30% of the driver's Sd.
If those are the real deal drivers with the shorting rings, etc, I 'd be hard pressed to bury them inside folded baffles.

Also, the thread you want about ripoles starts with a thread titled "Honey I shrank the dipoles". If I mentioned that ratio, then that's where I got the info.
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Old 16th September 2007, 05:41 AM   #26
zobsky is offline zobsky  India
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Quote:
Originally posted by theAnonymous1
Mine will also serve as the bottom portion of my speakers. The top will have a 10" driver fo the midbass/mids and then Heil AMT for the mid/highs.

Man, I really need to find someone local to cut some wood for me. I'm limited to what a jigsaw can do in an apartment.

Chops, your not going crazy; a ripole IS just a N/W baffle with restricted openings.
Can't you get the folks at Home Despot to cut you up some MDF (their saws are usually brutal on plywood)? Most of the pieces should be fairly similar in size. All you'd have to do at that point is make the cutouts using your jigsaw and assemble the unit.
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Old 16th September 2007, 01:23 PM   #27
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Default air mass requirement

For the W shape what is the requirement for air volume ( mass ) behind and in front of the driver. I would guess that the volume in front of and behind the driver should be equal. Additionally the openings should have the same area in front and behind ( per driver ).

Would this make it look like a slot loading on both sides of the driver?

Would the air volume be a multiple of the maximum that the driver can move at Xmax ? Say 3.33 times if the vent area is 33% Sd? Is there any relationship ?

Cheers.
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Old 16th September 2007, 01:31 PM   #28
Salas is offline Salas  Greece
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Is the sound of a W frame as uncolored as the sound of an H frame?
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Old 16th September 2007, 02:05 PM   #29
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Since the W frame has a shorter path to the exit, maybe it should have resonances starting at a higher frequency and so be cleaner sounding when used with an appropriate crossover ?
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Old 16th September 2007, 03:29 PM   #30
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Quote:
Originally posted by zobsky


Can't you get the folks at Home Despot to cut you up some MDF (their saws are usually brutal on plywood)? Most of the pieces should be fairly similar in size. All you'd have to do at that point is make the cutouts using your jigsaw and assemble the unit.
These will hopefully be my permanent subs for the foreseeable future, so Home Depot is not an option. I know from past experience that their cuts can be WAY off. I also want to do magnet cutouts on the outside walls with a router which I don't have either.

ashok, Ideally you want equal openings on the front and rear. If your going for a "ripole" this usually isn't possible because of the size of the basket and magnet. You can make cutouts for the magnets, but the basket will probably keep you from getting an opening ~30% of Sd. From what I've seen most people just make the back opening as small as possible and then apply the ~30% Sd rule to the front opening.

The "volume" of the opening isn't relevant other than you want it as small as you can make it; i.e. just big enough to fit the driver. This helps push the resonance up in frequency. It's the area of the opening that is important.

My front cavity will be 15.5" x 15.5" x 2.5". The back will be roughly 15.5" x 15.5" x 4".
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