[rajacat]

Can you get pinpoint imaging with OB? IOW, in symphonic music can all the instruments be very accurately placed in space in three dimensions. Can you walk between and around the speakers and get the impression that you are strolling among the musicians and you can point to the various instruments which,of course , are instantly identifiable by their perfectly reproduced tone. aa

-Roy

[Graham Maynard]

Hi Roy,

I think the moment you walk 'around' any one loudspeaker of a stereo pair other than an omni, then you are leaving the 'stage'!

Between the loudspeakers, driver radiation patterns are bound to modify a stereo 'image' with position no matter what kind of construction there might be behind a baffle.

Cheers ........ Graham.

[-Richard-]

Hi Roy ~

Yes... Harbeth allows the front panel of their speakers to move... to float a bit with the front wave and the material is supposed to contribute to the all-over tonal presentation... but the
"floating" front panel also contributes to the "openness" of the sound.

"Can you get pinpoint imaging with OB? IOW, in symphonic music can all the instruments be very accurately placed in space in three dimensions. Can you walk between and around the speakers and get the impression that you are strolling among the musicians and you can point to the various instruments which,of course , are instantly identifiable by their perfectly reproduced tone."

I grew up in the explosively experimental period in audio of the 1950's. When stereo sound was first introduced there were records that "miked" a person walking across the stage from one speaker to the other, cars and trains moving from one speaker to another and so on. I was young enough to be thrilled by it... it was quite a treat... but in reality it was little more than a novelty.

So what interests me now? A richly palpable visceral tonal palette, a 3-D holographic spacial field, the emotion of the music or voice transforming my feelings into vibrations that thrum and pulsate with the music.

You could divide audio into 2 polarities... just to point out what I am getting at... on one side there is pin-point "accuracy" and on the other there is deeply felt emotion and a powerful connection to the music and voice. I am older now... what I am looking for is a powerful connection to the music and voice.

My DIY OB's do that for me with the right amplifier and preamp. I respectfully view audio design that stresses "accuracy" as novelty.

If you are happy with your current speakers that is all that matters. No need to convince anyone of the "truth" of your experience... most of the OB enthusiasts on this thread, myself included, have had quite a number of speakers and amps we have played with over the years.

Isn't it nice to know that if the spirit moves you that there is yet another speaker modality you can experiment with?

Enjoy, Roy.

Warmest Regards ~ Richard

[D OB G]

Hi Roy,

When you talk about pinpoint imaging, are you questioning whether OB speakers can do things like:

- in a classical music setting, for example, have the orchestra start 10, 20 meters? from behind the speakers, and then itself extend another 10 meters back to the percussion, all in your own living room, in correct overall loudness and proportion?

- reconcile the fact that many recordings are a composite, done on different days (with the chance, as is often heard by professional musicians, of different ambience).

- reconcile the fact that many instruments are dubbed (e.g. organs off site)

- reconcile the fact that typical solos e.g. woodwinds in particular are "spot" miked, and then left to disappear into the overall mix.

- reconcile the different microphone configurations, such as Blumlein crossed stero pair, versus RCA  (I think) "wall of sound" miking , versus a Russian Melodiya technique of placing mutiple microphones set into the stage in front of the orchestra.

... and many other considerations that others can no doubt think of.

My point is that I have heard many speakers give a fine musical account of orchestral music (with the right recording), in spite of the "tricks" and "traps" that seem to apply in one way or another in most large scale recordings, but to equate that with pinpoint accuracy may be the search for an artefact.

(Close your eyes at a concert and see if you can differentiate the principal cello from the rank and file in space, or the first basson from the second basoon, in space, for example from 20 plus meters away, with an orchestra doing its thing).

Just one angle.

David

[rajacat]

My question wasn't intended to be argumentative but rather a honest inquiry about what sort of sonic landscape the OB configuration is capable of delivering. My present speakers, Omega Hemp Bipoles, which I run in the optional dipole mode, do present a wide enveloping soundstage. I can walk around and between them and the instruments retain their positions and it sounds like I'm among them. I can point to the location of groups of instruments. I agree, at a concert it is almost impossible to distinguish between individual instruments lets say, in the violin section. Actually I'm fairly happy with the Omegas even though I haven't optimized the amplification and some other things. Those (4) 4-1/2" hemp drivers are tonally rich and amazingly quick. Presently I'm awaiting delivery of some Heathkit kt66 monoblocks which should further enhance the holographic imaging and tonal richness. Surprisingly the little Trends 10.1 (+some simple mods and battery power)used in conjunction with a Mapletree tube pre really do, to my neophyte sensibilities, provide a moving audio experience.

That said, I'm open to new ideas and when I get a little more time, build some OB speakers.

-Roy

[D OB G]

OK Roy, point taken.

Lucky you that you have enough room behind the speakers to walk around them!
Imaging improves the further away from the walls the speakers are placed.
Cardas gives a formula for the layout of a room with OB speakers, and they are a long way from adjacent walls.
One aspect of OB speakers that is relevant to imaging is whether the driver is centered or not. 
JohnK, (a true expert on the subject- musicanddesign.com) shows that an off-center driver skews the polar response, effecting imaging, and the power response.
Both Linkwitz (a true expert on the subject) with his Orion, and JohnK with his Nao, use drivers centered in the vertical plane.
However neither use horizontally centered drivers (there is a bass box under each midrange baffle) because there is a conflicting requirement to make the baffle as far from a circle as possible, with the driver not centered, to ensure as ripple free a response as possible above the baffle cut-off.
This can be mitigated, or eliminated with sophisticated equalization.
There would be differing opinions as to whether a narrower baffle gives better imaging.
There is a program, that you might be aware of, called the Edge (freeware) that can model the responses of various baffle shapes (with limitations that have been discussed in this forum), that shows that a rectangular baffle should be close to the golden mean 1:1.618, and that the driver should sit on the baffle close to the golden mean for minimum, or best controlled ripple above the baffle cut-off frequency.
This however does compomise the imaging compared to a vertically centered driver.
Another option to reconcile the two requirements is to use a vertically centered driver on a rectangular baffle with the top sloped (trapezium).
Given all this, there is no reason why imaging with OB should not be as good as other alignments.
There are advantages with OB bass that the room fundamentals are less excited, leading to a smoother bass, and with a rear facing tweeter (not for everyone) the power response in room can be more even, which can be preferred for imaging, especially if the rear radiation of the midrange is relatively free from obstruction (e.g. open cast chassis and alnico or neodymium magnet).
Having said all this, I don't believe any OB design is going to give the presentation of a stand mounted mini-monitor, and neither would I expect any fan of OB to want that.

David

[Anglo]

Hi

Good thread!  Being an OB fan for 3+ years now, Staging-while very low on my list-is quite amazing with OBs IMO.  What is so fantastik about OBs is their immediacy, their dynamics and their articulate bass.

They have horn like dynamics without the horn colorations, they have immediacy the energy  is not stored in a box.  This energy that boxes suck up is quite inevitable when one listens to an OB for an extended period of time and then goes back to a box sound.

Lastly, combining a high efficient wideband driver, a high efficient woofer with small and agile amps just adds to the pleasure of listening to any type of music.

Best,

Steve

[Duke]

To Rajacat:  I used to be a dealer for Clayton, but he's no longer marketing through a dealer network.  But let's just say that in my opinion he sets the bar very, very high at that price point.  And dangit, now I have to contemplate building a speaker to compete with him, because I can't sell his anymore.  I've been told that both Clayton and I received Golden Ear awards in the latest issue of TAS, and maybe the reviewer (Robert E. Greene) made some comparison comments.  My copy hasn't arrived yet, but the fact that both were awarded implies that both are worthy in their respective price ranges.  I can e-mail you links to some online commentary from a fairly well-respected (in DIY circles) individual who listened to my speakers and Claytons at RMAF '07, if you would like.

To JLM:  Sounds to me like you have a good understanding of bipolar speakers.  A bipolar has the possibility of deeper bass (before equalization) and greater amplifier-friendliness than a same-sized dipole, but the design will fail to compete with a dipole if there's any audible boxiness.  I doubt that bipoles will ever be as popular as dipoles with the DIY community, as they lack the dipole's elegant simplicity.  In fact, getting a bipole "right" is somewhat more complex than with a monopole box, and several different approaches have been tried by different manufacturers.  But, that's another topic.

To opnly bafld:  Touche'.  But note that my big bipoles were designed to compete in a different price range. 

Duke

[gainphile2]

My experience, anything trying to replace my OB (boxed, hybrid box-ob, omni) got removed within 1-2 days