Horn speakers with Imaging?

Nice seeing S.P. Tech (by Bob Smith) mentioned by @audiokinesis, although back in ’05 now. I owned a pair of their Timepiece MkIII model around 2010. Two friends of mine still use the Revelation model in their respective setups, one running the Rev’s full-range and passively configured, the other fully actively and subs-augmented (with the Rev’s high-passed). Bob worked on a Grand Rev model with dual 10" Seas woofers (same as used in the Rev’s, just bigger) and an oval waveguide, a behemoth of a speaker, but it never got to see the day of light before SP Tech went under. Especially the subs-augmented and actively configured Rev’s of my friend image really, really well, and are somewhat more resolved and transiently clean than their passive counterpart (which are a fiendishly heavy load to most amps; they were developed with the Crown Studio Ref. I’s). It’s one of the few setups I’ve heard that can make a well-recorded large symphony orchestra come fairly authentically to life, even organ concerts, which is no small feat, though not least a testament to my friend’s ability to actively implement and tweak a setup in the extreme. That said they sound bottlenecked compared to my own, also actively configured setup with very different speakers for pro cinema use and Tapped Horn subs.

@willgolf wrote:

Does everyone have the same definition of imaging? In audio terms, what doe that word mean?

+1

From Alex Halberstadt’s Stereophile review of the Klipsch La Scala AL5’s:

The Klipsches created sonic images that were eerily, entirely life-sized and placed them on a stage as large as the recording and the room allowed. Combined with their hair-raising dynamic chops, this allowed the La Scalas to come uncannily close to creating the illusion of real musicians playing in a room. That’s a big-time reviewing cliché, so perhaps a more effective way to communicate this is to say that they reveal how radically most speakers—even large ones—miniaturize the dynamics and scale of recordings.

This to me underlines how a vital aspect of speaker "imaging" has become or rather for long has been a (limited) thing of itself in audiophilia - that is, as something that is less a representation of a live event and more a cultivation of sorts into the the smaller, more laidback ".. razor-sharp sonic holographs" that is so prevalently hailed by many in this hobby of ours. Later in his review Halberstadt writes:

Last, while the La Scalas throw an enormous and cavernous soundstage, they do not create the razor-sharp sonic holographs of the kind conjured by certain contemporary minimonitors. But if that’s crucial to you, you probably aren’t considering these speakers.

This may (or may not) to some degree tie into the following comment by John Atkinson in his measurements section of the La Scala’s:

... the tweeter’s output arrives first at the microphone. The output of the midrange unit doesn’t arrive at the microphone for another 1.5ms, while the woofer’s output starts to arrive 2ms after that. Although the arrivals of all three horn outputs are within the ear’s tolerance for arrival time difference (footnote 2), such behavior could interfere somewhat with stereo imaging precision.

Using horn-based speakers myself I can attest to the importance of either physically time aligning or (actively) digitally delaying the individual driver segments to more properly cohere into a sonic "simultaneity" of a presentation as a whole. One can almost "see" the radiation bubble forming more smoothly in front of you when carefully applying the right amount of delay, and the positive effects it has on spatial acuity. Certainly the "life-sized" aspect of imaging or overall presentation that Mr. Halberstadt touches upon - ideally in proper conjunction with delay or timing execution as well as attention into power response and dispersion pattern matching at the crossovers - in general is severely overlooked.

However to think that he was only presented to a fraction of a larger potential, while still being so enthused about what he heard through the La Scala’s, puts into perspective the outlook that is possible (and fully attainable) with horn-based speakers when more closely considering all or at least additional aspects in their implementation.

@o_holter wrote:

... although I havent measured the ’radiation bubble’ in front of my bipoles I can well imagine that it changes like you say.

I find it to be an almost visually descriptive term a la ’sphere of sound,’ a sensation that can be created more effectively with certain point source speakers when the driver segments have been dialed in successfully wrt. timing/delay, power response and overall dispersion type/pattern - ideally emulated as a point source like Tom Danley’s synergy horns.

But what do you mean by ’life sized’ imaging? That images should not be too tall? Or too close up? Too bombastic?

In reference to the linked La Scala review by Alex Halberstadt, and supporting my own stance, ’life sized’ is addressing and exposing the lack of image size/scale from other speakers, and where the reviewer found the La Scala’s to excel by comparison.

Though it’s not explicitly clear it seems to me he may be linking overall image presentation and size with dynamic capabilities as directly proportional aspects, at least to some degree. This certainly makes sense to me in how dynamic prowess can more effectively "flesh out" the presentation - perhaps aided by the more narrowly dispersive nature of horns/waveguides - as something perceived akin to a live event.

Moreover the effective air radiation area of horn-based speakers is somewhat larger vs. direct radiating and lower efficiency dittos in that the combined displacement isn’t only dictated by the mouth areas, but rather extends (i.e.: grows) even further in front of the horn mouths. So, the combined air radiation area of the La Scala’s could easily be seen as taking up more than the totality of its frontal area. That being said the La Scala’s aren’t the tallest speakers around, and to me at least I find them to lack energy and ultimate fullness in the height dimension to really give that sensation of room fill and less-reproduced feel that taller horn-based speakers can more properly provide for.

Well designed, and not least larger horn profiles/geometries (and to some degree depending on the amps) aren’t up-close or creeping into your ears per se, but are rather present or immediate sounding. There’s a difference. All things being fairly equal; the larger the horn the less "aimed," more relaxed and yet physical it sounds - not wholly unlike the presentation of larger panel speakers, but more dense and visceral by comparison.

I find that this varies with the recording and production, and when the presentation is too forward and in my face, I push the listener chair back.

If the front/aft balance is right, and there’s no reason it can’t be with horn-based speakers, then the recordings and their variations in presentation should see no immediate need to shift listening position, but I guess that’s up to each to decide.