Upwards aligned open baffle? ( pop box meets open baffle )

Hello all!

Since reading that open baffle sounds nice and has a better radiating pattern I've thought of merging the Carlsson inspired pop box with the open baffle concept:

It would be used primarily for music listening on low volume, no earthquake capable sound needed :p

Dipole/Ripole subwoofers to handle up to somewhere 100 - 300, or as high as they can handle while still performing optimally.

Then do an open baffle with upmounted full range driver surrounded by four inwards mounted tweeters to help from about ~ 4-5 khz and upwards, for if I'm not mistaken the FR driver would in these higher frequencies have inadequate dispersion.

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The baffle would stand on for example on legs and stand 50-70 cm high.

The idea is to create an open baffle speaker without a soft spot inside the room, I move around in the room and want to enjoy the sound everywhere.

MiniDSPs would be used to handle sub -> OB speaker crossover and EQing while the FR and Tweets would be passively crossed, maybe active there too in the future though.

Do you think this could work or is there a better existing solution that would also give me softspot-less sound? Since open baffle supposedly already have a good spread would it still be advantageous to flip it horizontally or is it better to have the baffle vertical as normally done?

And if it would work, approximately how large would the baffle have to be? Would it have to be gigantic or can one get away with something in the line of 25 x 45 cm?

// Olle

EDIT:

This might be better placed in "Multi way", so if it should and some mod sees it maybe they can move it? =)
 

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Of the few omni-directional speakers I've heard they sounded best placed at a central location, as opposed to the more traditional stereo arrangement.....is this the plan? Of the few OB speakers I've heard, I did always enjoy the dipole effect they have on soundstage......they have a sense of space I've not heard on a boxed speaker. With that said, I don't see a point in going OB here, as you'll just be sending all the reflective energy into the floor. I doubt any fullranger is going to have the dispersion to listen at any distance, so IMO you'll exacerbate the "dead spot" issue ten fold (instead of having a room response gap, you'll have a massive gap in the speakers response. Additionally, dependent on the moving mass and suspension compliance of the driver, you could run into sag issues. I could be way off...try it and report back.
 
Both yes an no, the ideal is to have a fairly traditional stereo arrangement BUT where I'm not limited to a central soft spot of listening but instead can move around the room.

Sure, I will sometimes hear the left channel with higher volume than the right but thats okay, but I want to hear all frequencies of each channel with equal loudness wherever I am. In other words, I don't want to loose treble if I move out of some soft spot =)

I've also thought of using traditional BR clones of that original speaker but with a Dipole sub crossed right below you can hear directionality, or stereo Dipole subs with smaller BR speakers ontop of them.

But the idea here is to remove all noise from having an enclosure that supposedly Open Baffle should solve, right now I have BR clones of that speaker which works really well, no soft spot at all which is why i thought about improving it more.

So an idea, as it is now the reflections are directed to the floor yes but what if you placed a cone underneath?

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Wouldn't down reflections then be directed around it?
 

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My final experiment of this type of speaker used a stuffed U-frame for the woofer and a sealed sphere for the midrange.

Overall the speaker worked well but I wanted to be more scientific and compare different speakers so I also built a rough pure dipole.

My assumption was that I could check off the "I've tested open baffle dipole and concluded my omni sounds better" box. When I did A/B listening though I found the opposite. The open baffle sounded much more clean, it wasn't even close. In all experiments since I haven't yet succeeded in designing a sealed or sealed-ish speaker box that sounds as clean as an open baffle.

I'm not sure if the sound problem has something to do with the radiation pattern or if there is just something inherently problematic with trying (failing?) to contain the back wave. It's really frustrating because I have measured a lot and I can't detect any significant difference in the measurements but I can hear it very clearly, it is night and day. In one of my experiments with a small full range leaky cardioid with baffle I got measurements that were almost perfect: a consistent cardioid response over the whole frequency range from 200 - 14000 hz. No ugliness in the impulse response either. Still sounded like I was listening through a tube compared to the pure dipole version.

So in the end I've pretty much abandoned non OB projects, my current project is a full range dipole CBT array. Although I might experiment with a leaky cardioid again but instead of using a hard box material like foamcore build it only using lossy materials like wool of different density. Should give me a box with less problems from standing waves at least. Mostly since It would be interesting to have the sound of an open baffle but with a cardioid response instead of dipole.

Footnote: When comparing dipole vs sealed I take two identical drivers and build as close to identical speakers where one is sealed or ported and one is open baffle, and then EQ them to measure identically.
 

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