Why no bipole speakers ?

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#6
The bipole helps a lot with the loss of bass due to baffle step. The issue to watch out for is that with a bipole, you cannot place it too close to a back wall or you get a big cancellation dip due to reflection from wall. My sims show a distancenofncirxa 4-5ft away from nearest back wall.

Some sims and a build of a 4 driver bipole MLTL here.

http://www.diyaudio.com/forums/full-range/234535-tangband-w3-881-mltl-build.html
 
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#7
The several bipole FAST configurations we've built to date have all had side mounted bass drivers, and certainly one of the issues with them is placement relative to side walls, etc. - they tend to be even more persnickety that mono-poles. In Dave's large main living / listening room, that's not as big a problem as it can be in a 400 or less sq ft space with furniture, asymmetrical room boundaries, pony walls, yada yada

Front to back bipoles also have issues - similar in my experience to large dipole planars or OBs; you know - at some point the room acoustics get in the way of what you hope to accomplish with an exotic design, and effective treatment can get bulky /expensive.
 
#8
Some "explorers", are evloving bipole speaker ambience goals into enhancing left+right 2-speaker stereo "up front" sound stage imaging, into a more realistic "around the room" spacial image.

Example: Front 60-degree angled-in Econowave speakers providing both the imaging and dynamics for a proper front sound stage, agumented by a separate stereo pair of under-200Hz short-horn midbass speakers aimed toward the ceiling and rear wall.
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Duke ..... the owner of the AudioKinetic Company

"As music lovers, what are we looking for in a high-end audio speaker? The closest approach we can reasonably make to recreating the perception - the feeling - of being in the presence of live music. Timbre, inner detail, and dynamic impact are all a part of this. But perhaps the most elusive aspect is image density - that is, the perception that the sound-source images we hear in space have body and weight to them. This goes beyond the pinpoint imaging of a good mini-monitor, and beyond the rich sense of envelopment of a good omnidirectional system, though it includes aspects of both.

The key to recreating sound images that feel like the real thing is to set up a powerful, diffuse, spectrally correct, fairly late-arriving reverberant field. When done right, the ear-brain system interprets this reverberant energy as confirmation of the imaging cues in the first-arrival sound and we perceive those sound images as having realistic density.

The Dream Maker LCS system uses a high quality pair of main speakers to generate the desired first-arrival sound, and then a pair of separate, dedicated, highly directional upfiring array modules adds the extra spectrally-correct reverberant energy, with the required time delay coming from the long path this energy takes bouncing off the ceiling before reaching the listening position. The Late Ceiling Splash configuration is the invention of James Romeyn, and could be considered an advanced evolution of the controlled-pattern bipolar configuration first seen in the original award-winning AudioKinesis Dream Maker. "

Home
 
#9
For the purpose of correctness regrading Duke LeJeune of AudioKinesis, you can go to his web site given by LineSource at:

Home

Duke's child board AudioCircle forum is at:

Duke LeJeune, AudioKinesis Loudspeakers

You can likely search back in time to read his earlier work on bipoles.

I used some of Duke's bipole work for some of my projects on bipoles here on diyaudio. His off set driver locations idea can lessen the around the cabinet resonance for bipole speakers.
 
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#10
I was thinking that this Xmas season some experiments might be in order. If I were to go with a TC9FD, based on the positive results reported on this forum, for the full-range, which drier would be a good one to consider for the supporting woofer ? I'd prefer a small driver and accept that there will be limitations to SPL as I already have big speakers in the house this would be a challenge to achieve decent results in a smaller, stand mount, enclosure.


A mini DSP might allow some funky experiments with the bipole approach - I don't have a mini DSP but perhaps Santa will bring me some new toys.
 
#11
LineSource said:
Some "explorers", are evloving bipole speaker ambience goals into enhancing left+right 2-speaker stereo "up front" sound stage imaging, into a more realistic "around the room" spacial image.

Example: Front 60-degree angled-in Econowave speakers providing both the imaging and dynamics for a proper front sound stage, agumented by a separate stereo pair of under-200Hz short-horn midbass speakers aimed toward the ceiling and rear wall.
-----------------
Duke ..... the owner of the AudioKinetic Company

"As music lovers, what are we looking for in a high-end audio speaker? The closest approach we can reasonably make to recreating the perception - the feeling - of being in the presence of live music. Timbre, inner detail, and dynamic impact are all a part of this. But perhaps the most elusive aspect is image density - that is, the perception that the sound-source images we hear in space have body and weight to them. This goes beyond the pinpoint imaging of a good mini-monitor, and beyond the rich sense of envelopment of a good omnidirectional system, though it includes aspects of both.

The key to recreating sound images that feel like the real thing is to set up a powerful, diffuse, spectrally correct, fairly late-arriving reverberant field. When done right, the ear-brain system interprets this reverberant energy as confirmation of the imaging cues in the first-arrival sound and we perceive those sound images as having realistic density.

The Dream Maker LCS system uses a high quality pair of main speakers to generate the desired first-arrival sound, and then a pair of separate, dedicated, highly directional upfiring array modules adds the extra spectrally-correct reverberant energy, with the required time delay coming from the long path this energy takes bouncing off the ceiling before reaching the listening position. The Late Ceiling Splash configuration is the invention of James Romeyn, and could be considered an advanced evolution of the controlled-pattern bipolar configuration first seen in the original award-winning AudioKinesis Dream Maker. "

Home
Click to expand...

I was under the (mistaken?) impression that the LCS modules employed by Duke have a more extended frequency response than this, and I seem to recall seeing pictures that showed an array of woofers surrounding a single tweeter; at the same time, though, I've heard it said before that the "proper" way to to it is to sharply bandpass the augmenting modules.

Can anyone offer some thoughts as to what the thinking is there?
 
#15
chrisb said:
The several bipole FAST configurations we've built to date have all had side mounted bass drivers, and certainly one of the issues with them is placement relative to side walls, etc. - they tend to be even more persnickety that mono-poles. In Dave's large main living / listening room, that's not as big a problem as it can be in a 400 or less sq ft space with furniture, asymmetrical room boundaries, pony walls, yada yada

Front to back bipoles also have issues - similar in my experience to large dipole planars or OBs; you know - at some point the room acoustics get in the way of what you hope to accomplish with an exotic design, and effective treatment can get bulky /expensive.
Click to expand...

I'm more interesed in the front-back kind. And the room interaction is part of the interest.
 
#18
Bigun said:
I'v also been interested in the positive reviews of the new FF85wk. Still, question is, which small woofer ?
Click to expand...

And the FF85wKeN are better yet. I just swapped out the A7+A12pw MTM and hooked up the Tysen V2 protos (FF85wKeN + Silver Flute W14 (1 each side) in a Woden ML-TL).

Still haven’t got them 100% tuned it, but 1st impressions are good.

How small is small?

There are a huge number of possible candidates. The W14 is really good, irregardless of its budget price. We have also used Peerless 830870, EL166, A12pw, SDX7 with good results. Have a design (unbuilt yet) with a pair of vintagish Foster 12” (i’ve got north of a dozen of those, gotta use em up).

dave
 
#19
I'd like to hear both the vifa and the fostex full-range options. I was never happy with the fostex driver I had many years ago, too bright, but I will admit it has magic. The FF85wk has it's resonant peak at a much higher frequency, above the 'presence' region so I thought this might make it workable. The vifa I have no experience with, but I do have fountek 88's and they are smooth sounding so I know what can be possible. Perhaps the best idea is to get both and hear them with my own ears. I am also thinking about angling the full range driver upwards so that at normal listening height the driver is always a bit 'off axis'.

Woofer? - again, the challenge I've given myself initially is a to conceive of a small standmount design for a smallish listening space. Therefore, the woofer should be not much larger than the full range. I'd like to make a relatively small enclosure and I'd like to minimize the group delay consequences of the usual vented box. So I figure this means operating the woofer(s) in a sealed cavity or with a resistive vent. I assume this means a small Vas. OR perhaps one of those arrangements where the woofer is driven below it's fs. It's all just reading and learning right now.
 
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