What exactly is "imaging" ?

[RJohan]

The M2 has a rather significant waveguide/horn on its tweeter to get a good directivity match from two very mis-matched driver sizes.

Yes, that's what horns do, match the driver to the air, it's in the first page in all books/papers on horns. Not exactly new or rocket science.

 

[RJohan]

They've been designed for high-SPL and a pretty Spinorama (it doesn't mean they won't sound good though).

Edit: from JBL I'd rather have the S9800s or S9900s (with a pair of subs).

With S9800/S9900 I just would get a silly 'supertweeter' I can't hear anyway (I'm 63) and don't believe in or want to pay for. They look a bit nice than the M2's, but the M2's looks a lot better than my 4331B's in DIY 'chipboard heaven' enclosures.

 

[davidsrsb]

I don't recall if it was in this thread or another but someone linked to a website that had recordings to test the phantom imaging / spatial abilities of your speaker setup. I don't suppose anyone remembers what the website was?

@tuga gave us this one
https://www.audiocheck.net/audiotests_ledr.php

 

[John Phillips]

I've just done the following test on my Ditton 66s to investigate my dissatisfaction with their phantom centre imaging at their current location in my room (I have them very wide apart and close to the corners of my room, toed-in to cross in front of my listening seat):
...
My results:
...
4) Fail? The Phantom Centre Stability is dead central for bass, but gradually and steadily moves out laterally towards the speakers as frequency increases.
5) Pass
6) Fail? Huge difference noticed for bass, significant difference noticed for midrange, but a much smaller difference noticed for treble.
...
I'd be grateful if others could run test segments 4), 5) and 6) on your speaker systems and report back, if it's not too much trouble? Thanks.

For me:

• 4) There was a small shift in image between the stepped section: Bass slightly to the left of center; midrange central; treble slightly to the right of centre. I barely noticed this on the swept section.
• 5) I'm not sure what to make of what I heard.
• 6) There was a fairly similar level of contrast between normal/inverted in the bass, the midrange and the treble sections. Perhaps the bass contrast was weakest here but not that much.

This room is certainly asymmetrical: mainly diffusion from the right wall and mainly reflection from the left. But the frequency response of this diffusion / reflection is unknown. The system's channel gains are slightly tweaked for a central image. So I do expect some differences in testing. However I don't find anything untoward when listening.

 

[John Phillips]

I've just done the following test on my Ditton 66s to investigate my dissatisfaction with their phantom centre imaging at their current location in my room (I have them very wide apart and close to the corners of my room, toed-in to cross in front of my listening seat):

My results: ...

Thanks for that link. As I wrote, my room here is certainly amplitude asymmetrical, but these tests seem quite good at suggesting that the asymmetry may also be frequency-dependent.

However, I think they also confirm that my channel gain tweak for getting a central image was just about right, and that although the remaining asymmetry can be heard with a test signal, it seems my ear-brain system does not find anything to which it objects when listening to real music. I have long been interested in finding out the threshold below which measurable audio things cease to matter (to me, anyway) in real life.