designing for imaging, soundstage

[blue934]

anyone care to share thoughts on baffle design/crossover points/etc. with regard to imaging and soundstage? haven't read much discussion on this topic here.

wayne j. has some ideas from the eros design a few yrs ago;
"The front baffle is 9.5" wide with an outer edge rounded with a 1 1/2" roundover router bit and the inner edge rounded with a 3/4" bit. This was done in combination with offsetting the woofers drivers 5/8" to the inside of the baffle's vertical centerline to improve imaging. The tweeter is offset 1 1/8" from the centerline toward the inner edge of the front baffle. The center to center distance between each woofer and the tweeter is 6.75" for reasons that will be more fully explained in the crossover design section. Don't be surprised that this number is somewhat larger than the center to center distance recommended by other designers, as my experience has found that this approach provides a taller, deeper soundstage with less compression in front of the speaker at the expensive of a slight amount of imaging that can be regained with a good quality amplifier and proper speaker placement in the listening room."

this sounds like a low crossover point is good but keeping c-c distance as far apart as possible with that crossover.? right, wrong? any differing or more complete views on how to obtain great imaging? how do these theories differ from MTM to TM? lots of of offset tweeters but haven't seen many offset mid/woofers.
searching for answers
david

[max_andrews]

I've heard a good thing to do to improve imaging is to slightly boost the response from 2-4khz by about 2dB, which is very slight. But sure enough if you read reviews of speakers that are said to have "great imaging," many of them tend to have this slight bump from 2-4khz.

[blue934]

interesting,
thanks
david

[planet10]

Good phase response (preferably no XOs in the critical region) and a low diffraction signiture help alot,

dave

[Thawach]

Originally posted by planet10
Good phase response (preferably no XOs in the critical region) and a low diffraction signiture help alot,

dave

may be correct.But it's not at all.

[tomtom]

Originally posted by planet10
Good phase response (preferably no XOs in the critical region) and a low diffraction signiture help alot,

dave

I hear so many opinions about where critical region is.

50-1500
300-3000
700-3000
1500-7000

So where it is?

Is there some well documented and accepted consensus?

Imaging and stage is on top on my priority list too.

[SY]

All of the above. Lobing and polar pattern are everything. Take a look at the waterfall displays that Stereophile shows to indicate off axis response. Speakers with good imaging that isn't insanely room-critical tend to have very consistent polar patterns without serious lobes. When you see responses with rollercoaster humps and dips off axis, you know that either the imaging and soundstage will be poor or that the ignoramus reviewer will comment on how great the speaker is because the setup and placement is so critical.

I would have to disagree with planet 10 regarding phase response; the phase response of an LS3/5a, for example, is a horror show, it has a crossover right in the upper midrange, a steep one at that, yet it's an imaging/soundstage champ. But the designers took great care about diffraction, lobing, and horizontal polar pattern.

[Magnetar]

I think this is purely subjective unless you have the same speakers and room that were used for the final mix of the recording. Even then what were they listening to/for? probably not 'imaging' or 'soundstaging' - more like tone and wholesomeness of the event - or the intent - of the final production.

[sdclc126]

I'm not a big believer in imaging/soundstage etc. - you rarely if ever hear any of the popular designers talk about it. Speaker placement/listening position are probably the real contributors here - build a properly designed speaker with quality drivers and the rest will fall into place.

[auplater]

Originally posted by sdclc126
I'm not a big believer in imaging/soundstage etc. - you rarely if ever hear any of the popular designers talk about it. Speaker placement/listening position are probably the real contributors here - build a properly designed speaker with quality drivers and the rest will fall into place.

Dunno about that... my BG line array dipoles produce a rock solid, you are there image as long as the source was marginally well recorded. Female solo guitar work has incredible "in your home" presence, as does solo piano.

Sometimes I actually jump startle if I'm doing something while listening, and a well recorded piece comes on... it's like there's someone else in the listening space all of a sudden.

I've grown especially sensitive to soundstage/imaging deficiencies, as the quality of my repro gear has improved through the decades. I believe dipoles / line sources are the way to go if you have the room to use them.

John L.