Advantages of Series Crossover vs Parallel for Subs & Open Baffle

I'm considering a new OB build. Two-way with Eighteensound xt 1086 and nsd 1095n driver paired with 12 inch drivers for a two way OB. Will this be a good candidate for a 1st order series filter?

I haven't settled for the woofer yet, but they should go up to 1300 hz.

Personally, I don't know... Only tests would tell ! Fortunately, for a 2-way serial crossover, the parts are few : one L , one C , an L-pad.

That said, I'd be reluctant to let a 12" woofer reach a FC as high as 1300Hz, but OK : why not after all ? It depends on the woofer abilities and again, a test will tell you if it works...

T
 
This could be a candidate for woofer

Beyma 12BR70​


https://www.beyma.com/speakers/Fich...hoja-tecnica-baja-media-frecuencia-12BR70.pdf

Beyma offer excellent, high performance and ruggered speakers - the 12BR70 is a typical sample. I use a pair of 12BR70 in my Omega Ripole Subwoofer :

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Since I have several pairs, maybe I'll build a project of large sealed enclosure with them also... But they can be used in Open Baffle too, since they have FS=30Hz / QTS=0.5 / N=93dB/w/m, and interestingly :
1703543457752.png

I never tested them in OB configuration, but it is certainly a valuable compromise for what you expect.

T
 
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Personally, I don't know... Only tests would tell ! Fortunately, for a 2-way serial crossover, the parts are few : one L , one C , an L-pad.

That said, I'd be reluctant to let a 12" woofer reach a FC as high as 1300Hz, but OK : why not after all ? It depends on the woofer abilities and again, a test will tell you if it works...

T
Test will show, but I would like to narrow down the opportunities first.
 
@tubelectron I'm still trying to figure out what makes a design a Ripole?
Is it lowering of the driver Fs by X percentage?? 10%???

Dave.

@Davey - have a look on my small website below :

https://guilhemamplification.jimdofree.com/hi-fi-other-projects/

There's some explanations on the Ripole (in French and in English), and links to good websites describing more in details the principle of this very interesting type of Subwoofer.

1703632707623.png


Search also for Ripole + Axel Ridtahler on google. There's many articles in English on the subject... And in German, of course ! ;)

T
 
@perrymarshall

At home I use large estats 60x200cm with pleasure (non constant directivity). Going to convert STH260 waveguide monitor made for father to maybe Exar-MEH. Bought Wavecor SW270 and Arylic 2.1 amp to try out 3 way DSP. This thread made me interested in hybrids.
I think an important consideration is direct sound vs room energy reflected sound.

It is so universal that speakers are unidirectional at low frequencies and beamy at high frequencies, that this sounds completely "normal" to the average audiophile. But as Linkwitz points out, the mismatch between direct sound and reflected sound is your ears' first clue that something is wrong.

A dipole that covers the full range on both sides inherently has a room energy response that matches direct response. That includes electrostics (with the caveat that most have very narrow HF dispersion).

A large Multi Entry Horn is also capable of doing this.

Aside from those few formats, no other conventional box type has a room energy response that matches direct sound.

Bose was onto this many decades ago and their 501, 601, 901 etc designs dealt with this. But their execution was very mediocre by audiophile standards. I always felt Bose had good engineers and clever engineering concept-wise, but their drivers and components were "shaving pennies" cheap and frankly I never thought their speakers sounded good.

But if you can imagine building any one of those designs with 2024 state of the art audiophile drivers and components, the result would be very different. For example, imagine a Bose 901 style design with nine MarkAudio or Tang Band W4-1337 4" Titanium drivers using DSP (I wrote about the cleverness of that design from a bass reflex perspective in a sidebar in Audioxpress here) - in other words, real high end drivers instead of $15 paper cone full ranges, it would no longer sound mushy and midrangey. It would sound more like an electrostatic with a nice wide sweet spot.
 
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Aside from those few formats, no other conventional box type has a room energy response that matches direct sound.
I would have to disagree with this, other types will as well. Also, are we conflating constant directivity with consistent direct to reflected?

Dipole is one of several types that can, if done properly, be closer to constant directivity in the typically problematic baffle step region, and it's fairly easy to try to some degree. Other speaker types can do this region potentially more consistently when you consider less reflections.. but it appears many find them more of a challenge so there are less examples around for people to talk about.

A large Multi Entry Horn is also capable of doing this.
Multi entry should have nothing to do with it. A two way multi entry covering a similar bandwidth to a single driver horn, on a similar waveguide should be more similar than they would be different.
 
Which other box types have room energy that matches the direct sound across a wide bandwidth, without adding extra drivers pointing in other directions?

I'm not sure there's a way to can get direct energy matching room energy without some form of Constant Directivity (by definition), but maybe there's a method I'm not familiar with. Does anyone know of a way?

You're right, Multi-Entry has nothing to do with it; multi horn systems will also work. Bass horns are huge, so the only way I know of to get room energy = direct energy without a speaker the size of a Klipsch LaScala (refrigerator) is with a dipole.

As far as I know, if you want direct energy to match room energy, the only way that I know of to achieve that besides dipole is with a large bass horn, that has HF drivers matching the directivity of the bass horn.
 
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Perry and I agree, if I understand properly, that constant directivity below 700Hz is a worthy goal. I guess that's for the same reasons, which I surmise we've likely observed. I don't agree that dipole is the only way to achieve it.. and that other ways may sound a bit different.

Davey, my conclusions are generally from a time before Floyd Toole came on the scene. On that topic, it has to be said that DIYing ideals can produce different ideas than a focus on the assessment of commercial offerings. It can also lead to very different speakers.
so the only way I know of to get room energy = direct energy without a speaker the size of a Klipsch LaScala (refrigerator) is with a dipole.
Indeed, that's one part of the challenge I mentioned. If we settle on the idea that it's constant directivity we're interested in, what is it about constant directivity that's good? The simpler view often spoken about is that it matters more above 700Hz. In that case, most waveguide speakers fill the requirement.. if done well.

What is the factor that helps down lower, is it the smoothness of DI or is it a freedom from reflections.. and how much does one play a role in creating the other?
 
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Let's be clear, I'm not the dipole evangelist who dismisses the value of other speakers. I've built just about every box type there is and I like all of them for various reasons.

If you want direct response to match room energy below 700Hz, you can make that happen with a very conventional very slim tower using an array of small woofers. Sealed or reflex. You can put HF drivers on the backside and you'll get the energies to match. That's more or less an omnidirectional speaker.

If you're going to eliminate reflections, you need a horn, or else a cardioid with multiple woofers and likely multiple amps and DSP. Like the Dutch & Dutch 8C. I think that's very cool, but it's not for the faint of heart.

You can also achieve this by shifting from dipole to monopole at a sufficiently low frequency that the Allison Effect (notch from boundary cancellation) doesn't happen. A dipole crossed over to a monopole sub at a low enough frequency will accomplish this.

Maybe you can also achieve these goals with sophisticated room treatments.

The only clean, simple and straightforward way I know of to make reflected energy match direct energy is with a dipole woofer and CD tweeters pointing both directions. Possible, even elegant with a 2-way.
 
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The only clean, simple and straightforward way I know of
Fair enough.

If you want direct response to match room energy below 700Hz, you can make that happen with
If we can leave out the practical issues for a simpler definition.. Constant directivity can apply at different angles (different DIs). You can have..

1. Very narrow DI for a maximal direct to reverberant field ratio,
2. A corner speaker for maximal reverberent field to early reflection ratio,
3. Omni-directional for maximal reverberent to direct sound ratio,

.. and everything in between.
 
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