Bipoles or open baffle?

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KT

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Joined 2003
#1
For those of you who have tried both, which do you prefer and why?

I'm thinking about doing something with the CCS-FR125 or Altec 755E.

I understand Dave Dlugos (Planet10) and friends really like the FR125 in bipole cabs, but I don't recall if he tried open baffle.

Thanks,
KT
 
#3
I prefer bipoles. Not for every driver though. If the driver does not exibit a monotonically rising response when unfiltered on a baffle, its implementation in bipole is bound to sound heavy.
 
#6
My experience is that they indeed influence low frequencies on a narrow baffled cabinet, in that they effectively eliminate baffle step correction.

My take, after playing with both designs is that bipoles are easier to get right since they just require proper cabinet design and can be a whole lot more efficient. Dipoles require much more consideration since they have dramatic drops at LF and peaks above.

But really, the difference for me is the dipole eliminates the enclosures contribution to the sound. The bipole is going to have resonances, back reflections through the cone, standing waves etc.

amt
 
#8
at low frequencies the concept of a bipole doesn't exist acoustically,
Click to expand...

hi sreten,

i am not quite sure what you mean, can you elaborate on that?

there are subwoofers with two woofers, each on oposite side of the enclousure, they can be switched to work in either way, as bipole or dipoles
long time ago i experimented with this and i liked bipole bass better (i had that on my page but removed it recently)
there are even commercial subwoofers like that, with the switch
so the customer can decide what he/she likes, bipole or dipole bass

ed
 
#10
For those of you who have tried both, which do you prefer and why?
Click to expand...

well, back to the original question, which was about the fullrange and what is better

to me the unswer depends on the compromises one is willing to make

we all know that there is no such thing as ideal fullrange driver
most of the fullrange drivers which makes it all the way to the top will have to sacrify the bass
so, to put this puny little driver either on open baffle or to the enclosure as bipole will most likely yield no real bass
/there is an approach where the fullrange driver sacrify the top end, then you can achieve real bass with it, either on open baffle or as bipole, depends on the driver, but that is not fullrange anymore, since it requires tweeter/

to achieve satisfactory bass on open baffle is relatively easy, just use large cone area appropriate Qtc driver on very very big baffle
not very many people are willing to live with such big baffle (its ugly, believe me, I used to have two in my livingroom)

the most logical way for me is to use fullrange on open baffle with some low fr roll of
i have tried it many times and the sound is great, just ...open, clean, uncoloured....
why would you even try to get real bass out of tiny fullrange driver, thats futile, you will most likely muddy the midrange, thats not worth it
/offcourse under some circumstances one can live with weak bass out of a little fulrange driver, that all comes to the compromises we are willing to live with/

ed
 
#11
Thanks for the responses so far.

I wouldn't mind using a sub if that means the panel of the OB could be made smaller. CanOB be designed to have a LF rolloff like this? Also, are there issues with matching to a sub?

Also, does dipole describe two drivers on an OB with one driver facing forward and one facing back? Are the drivers wired in phase or out of phase? What are the advantages of a dipole over a single driver on an OB?

Finally, why does a speaker like the Linkwitz Orion, which seems to use drivers on an OB and then a dipole(?) sub need such a complex filtering network. Is the issue in matching a dipole sub with the OB's on top?

Thanks. I'm just getting started on the speaker journey so your insight is much appreciated.

Best,
KT
 
#15
KT said:

I wouldn't mind using a sub if that means the panel of the OB could be made smaller. CanOB be designed to have a LF rolloff like this? Also, are there issues with matching to a sub?
Click to expand...

All open baffles rolloff in the bass. The bigger the baffle the lower
the frequency the roll off begins. So the cone moves the same
amount it would in a box but much less bass is produced.

KT said:

Also, does dipole describe two drivers on an OB with one driver facing forward and one facing back? Are the drivers wired in phase or out of phase? What are the advantages of a dipole over a single driver on an OB?
Click to expand...

All open baffles are dipoles.
The two drivers are wired so the cones move in the same direction.
The twin drivers with one reversed reduces 3rd harmonic distortion.

KT said:

Finally, why does a speaker like the Linkwitz Orion, which seems to use drivers on an OB and then a dipole(?) sub need such a complex filtering network. Is the issue in matching a dipole sub with the OB's on top?
Click to expand...

The active network must compensate for the baffle losses.
The Orions mid panel requires a large amount of boost at the
point it crosses over to the dipole sub.

The c/o point cannot be raised due to cavity resonances of the
dipole subs H-frame.

🙂/sreten.
 
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