Ultimate Open Baffle Gallery

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#4,001
I'm wondering how Goldwood says Fs is 33Hz, but impedance peak is firmly at 40Hz...

Half space means infinite baffle, no baffle loss in the measurement. So, looks like Goldwood might give nice response in OB without EQ, but it's Xmax is quite low 5mm. High distortion to be expected below 100Hz in OB.

12inch woofer 500x500 ob edge.jpg
 
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#4,004
Juhazi said:
You guys are now thinking about only on-axis response. The challenge with OB/dipoles is to maintain similar polar response 0-360 deg and throughtout the spectrum ((or as far low as the designer wants).

Eg. U-baffle works only for narrow range, like any fixed baffle width. This is why a dipole speaker will preferably be 4-way with variable baffle dimensions.

http://www.dipolplus.de/thema2.html
http://musicanddesign.speakerdesign.net/HybridDesignNaO_II.html
https://www.linkwitzlab.com/Sound_field/Field_control.htm#Field Control
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So this would imply that PAP style open baffle will have an odd/skewed soundstage. So what open baffle projects are they on here which are 4 way, variable baffle and passive crossover?

I’m guessing this is why. Horn loading, using a beyma tpl-150h for example in Spatial audio x5 is such as good thing as it helps resolve directivity issues.

I used to have LX521, loved them but dsp and multiple amps were a pain.
 
#4,005
perrymarshall said:
I'd just like to add: People conjure up with all kinds of ideas as to what an "ultimate" system might look like. Often they are extremely complex designs with lots of excess drivers or technology or whatever.

I wanted something that at least in outline form was simple and elegant. Well, with the "Two and a half way" crossover design and the coaxial driver, the very focused, well-behaved polar pattern and the dipole configuration, I think these achieve that. I don't think throwing money or components at them would make them better. I suppose extreme bass-heads might add a sub-subwoofer for flapping your pant legs below 20Hz but 99.5% of music lovers would find that entirely unnecessary.

These are stiff competition to anything you can buy in a store, or see at an audio show for less than $100,000; and they'll give most of the designs north of $100K a good run for their money.

I don't know of any other system I've ever seen that has this combination of attributes - constant directivity across the entire band 20-20K, flat phase response, pristine step and impulse response, dipole pattern, 100dB efficiency, 500 watt power handling, dynamic range to burn. The imaging and transparency are unreal. You can walk ALL around the room and the stereo image is stable wherever you go.

And most women (including my wife) think they're gorgeous.

I encourage you to build these and show them off here on the forum.
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I'd love LOVE to my money STRAIGHT into this build Brother. You've made something good,Simple and 👍😎.
I want any info you can share. I'm HIGHLY Interested.
 
#4,008
gregulator said:
Thought I’d share the center channel I’m working on to match my live-edge open baffle mains and subwoofers.

At BAF I saw the speaker camp SLOB and decided to do my own take on a slot-loaded open baffle.

I still need to sand and finish it, but I didn’t want to wait to hear it. I’m happy with the sound.
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Those slots are interesting, but look incredibly small. Do you have any measurements for the woofers themselves? in open air, in baffle, with xover?
 
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#4,009
#4,010
nicoch58 said:
really nice ! isn't the woofer slot load too small ? maybe 1/3 of sd
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Yes, I was worried the slots were too small but it sounds ok. Maybe I’ll try to widen them but I’ not sure of the best way to do that. I don’t have a good measurement setup at the moment… I tried taking measurements of my other speakers with an uncalibrated AT2020, but the measurements looked suspect (they said bass was down something like 40dB at 30hz when I could clearly hear it during sweeps). I should just get a umic.

I’m curious, theoretically, what is the problem with slots that are too small? Why is 1/3sd the best choice vs other ratios?
 
#4,011
gregulator said:
Yes, I was worried the slots were too small but it sounds ok. Maybe I’ll try to widen them but I’ not sure of the best way to do that. I don’t have a good measurement setup at the moment… I tried taking measurements of my other speakers with an uncalibrated AT2020, but the measurements looked suspect (they said bass was down something like 40dB at 30hz when I could clearly hear it during sweeps). I should just get a umic.

I’m curious, theoretically, what is the problem with slots that are too small? Why is 1/3sd the best choice vs other ratios?
Click to expand...
maybe all start with Pa article https://www.firstwatt.com/pdf/art_slob.pdf there is a lot of chat on forum...
https://www.diyaudio.com/community/threads/pass-slob-build-discussion.300952/
 
#4,012
It would be interesting to hear these. I wonder if their performance has something to do with the "velocity squared" that Nelson described,

"The motional energy imparted to the moving air is proportional to the mass of the air times the velocity squared. The “squared” part means that if you triple the velocity you impart nine times as much energy, or about 9 dB worth. This raises the efficiency of the speaker quite abit, and it improves the transient response as the apparent mass of the air moved is higher inrelation to the cone mass of the drivers."

"The way this is accomplished is by “squeezing” the air through an opening narrower than the
surface of the moving diaphragm of the driver. In the diagram above, the air pushed by the
cones has to exit out the front of the loudspeaker through a slot opening whose surface area
is only about one third that of the cone drivers, and so it goes out about three times faster
than the velocity of the cones."
 
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