S12 OB - Returning to true OB

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This one is to build a true open baffle with its simplicity (no h/w/u -frame etc.) I think there is something about them which other variation simply can't match.

Obviously the low-end output is severely limited :D.

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Still using my set of previous drivers:

Hivi K1
Seas L21 RNXP
Jaycar CW2119

Active XO and 3 amps.

Any comments ? :cool:
 
Very nice! :):up:

By the way, what are the crossover points/slopes?

And...can't resist this question: How would you compare it with Pluto's?

Thanks. The slopes are 1.5khz and 120hz. All LR4. Some usual SLP and notches for OB.

Yes, Pluto (clone) is a love-hate relationship. They have the best holographic and realistic imaging, yet the sound is coloured by the "box". One immediately notice this when swapping over. I've done numerous swaps before.

So this S12 imaging is close to Pluto, but not there yet. For that I have to use narrower baffle like my "S9". But tonality and "purity" of sound they're miles ahead.
 
Add wings :)

Ah, yes. But then I'm back with the u-frame problems. I can't put my finger on it but using h-frame or (worse U-frame/wings) there is some degree of lost reality and the brain is not easily fooled into the illusion.

My only explanation is, with h/u frames the polar response is not as uniform as simple OB.

This is abit unfortunate as I have wanted to build 4 woofers/channel dipole bass array as in my previous thread.
 
So this S12 imaging is close to Pluto, but not there yet. For that I have to use narrower baffle like my "S9". But tonality and "purity" of sound they're miles ahead.

To the right on top of the 6.5'' midrange driver in the picture are two Dayton ND20FA-6. They are mounted back to back in a short piece of plumbing tube. Diameter of this 'point source' is 4,5 cm, depth is 3,3 cm.
I have not listened to them yet, still using the double Monacor DT 25N on the left. But the Daytons are almost half that size and should be even better imaging.
 

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Ah, yes. But then I'm back with the u-frame problems. I can't put my finger on it but using h-frame or (worse U-frame/wings) there is some degree of lost reality and the brain is not easily fooled into the illusion.

My only explanation is, with h/u frames the polar response is not as uniform as simple OB.

This is a bit unfortunate as I have wanted to build 4 woofers/channel dipole bass array as in my previous thread.

Yes I understand ;) and I am agree with you. But you can take the advantage and keep a good polar response.

The wings don't need to be long, 4" (10cm) maximum and it is OK. You could win a little more bass +3dB or more. Perhaps you already have done this ?

Have fun !
 
Regarding baffles and No baffles,

Gainphile seems to take a step 'backward' with this new baffle and Rudolf, as always, going front to improve our stereo sensation.

Couldn't the two of you settle this discussion, also provoced by Stig-Erik's thread, of baffles or no baffles, small or more substantial, by measuring various baffle sizes and no baffles at different angles. I suggest 1 m distance and 15, 30 and 45 degree angles, in room measurement. This would be very clarifying for our future developments.

We have the 2.2 diameter guideline, but what we don't really know is if some baffle is better than no baffle.

It would be very interesting if there could be arranged some controlled measurements to illustrate this question.

/Erling
 
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To the right on top of the 6.5'' midrange driver in the picture are two Dayton ND20FA-6. They are mounted back to back in a short piece of plumbing tube. Diameter of this 'point source' is 4,5 cm, depth is 3,3 cm.
I have not listened to them yet, still using the double Monacor DT 25N on the left. But the Daytons are almost half that size and should be even better imaging.

I have a handful of ND20FB drivers I've meant to do the same thing with - the only issue I see is power handling. Tell us if they burn! Otherwise, they look to be very good for the application.

Regarding baffles and No baffles, Gainphile seems to take a step 'backward' with this new baffle and Rudolf, as always, going front to improve our stereo sensation.

Couldn't the two of you settle this discussion, also provoced by Stig-Erik's thread, of baffles or no baffles, small or more substantial, by measuring various baffle sizes and no baffles at different angles. I suggest 1 m distance and 15, 30 and 45 degree angles, in room measurement. This would be very clarifying for our future developments.

/Erling

There are lots of measurements around the forum - the results are fairly simple - the smaller the baffle, the higher the dipole peak. Dipole speakers maintain a uniform off axis response up to about the dipole peak, then it degrades. (Additionally, the magnet/frame structure interferes with things in the 1-2kHz range.) The compromise with smaller baffles is more low end loss of sensitivity. How anyone wants to apply this is up to them and subjective.
 
This one is to build a true open baffle with its simplicity (no h/w/u -frame etc.) I think there is something about them which other variation simply can't match.

Obviously the low-end output is severely limited :D.

Looks nice! I enjoy your explorations. Something to consider wrt the 'sound' of your woofers is that you are probably pumping more power into them - so if you wanted more things to 'worry' about, you might be getting more heating in the voice coil, and distortion from your amp. Just food for thought. I worry about this stuff, but only a little.

:D
 
Cuibono, thanks !

I was not really aware of your observations. I can see that baffle size is very much dependent of subjective thoughts and some objective overwiews regarding baffle size. Possibly the 2.2 rule of thumb would be the best then ?

/Erling
 
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