There is another, somewhat unorthodox technique for getting a wide sweet spot, which works well with controlled-pattern speakers.
By way of background: The ear localizes sound by two mechanisms: Arrival time, and intensity. If the arrival times from both speakers are identical, the image will be shifted towards whichever speaker is loudest. And if the intensities are identical, the image will be shifted towards whichever speaker’s output arrives first. With conventional speakers, as you move off to either side of the centerline, the near speakers "wins" BOTH arrival time and intensity, thus the image shifts towards the near speaker, often dramatically so.
What I’m going to suggest is sometimes called "time-intensity trading", as the off-centerline listening locations which have a later arrival from one speaker compensate by having greater intensity (loudness) from that speaker.
Briefly, start with speakers which have a very uniform radiation pattern of perhaps 90 degrees wide (-6 dB at 45 degrees off-axis to either side) over most of the spectrum. Then toe them in severely, such that their axes actually criss-cross in front of the centeral "sweet spot".
For an off-centerline listener, the NEAR speaker naturally "wins" arrival time, BUT because of the aggressive toe-in and relatively narrow radiation pattern width, the FAR speaker "wins" INTENSITY!
For example, the first photo at this link is taken from a listening position which is well off to one side. As you can see, at this location you are on-axis of the far speaker but well off-axis of the near speaker. So the far speaker is actually LOUDER at the frequencies which matter most for image localization!
https://parttimeaudiophile.com/2019/06/17/new-gear-from-audiokinesis-and-resonessence-labs-t-h-e-sho...
With this configuration (and speaker type), these two localization mechanisms - arrival time and intensity - approximately offset one another, and you get an enjoyable spread of the instruments even well off the centerline like where that first photo was taken from. It’s not perfect of course, but it’s arguably about as good as far off-centerline listening is likely to get without advanced signal processing (like the Beolab 90).
The KEY to this technique working well is, the output of the near speaker must fall off SMOOTHLY and RAPIDLY as we move off-axis. In other words, this technique will not work well with most loudspeakers.
Of course the imaging will be best up and down the centerline, but elsewhere in the room the soundstage will hold up considerably better than normal. Spacing the speakers a bit wider apart than normal helps maintain soundstage width. A welcome side-effect of the speakers’ well-behaved radiation pattern is that the tonal balance holds up unusually well throughout the listening area, though a good omni will probably do better in this respect.
Here is a link to an article on the subject, I don’t know who the author is:
http://www.libinst.com/PublicArticles/Setup%20of%20WG%20Speakers.pdf
Duke
By way of background: The ear localizes sound by two mechanisms: Arrival time, and intensity. If the arrival times from both speakers are identical, the image will be shifted towards whichever speaker is loudest. And if the intensities are identical, the image will be shifted towards whichever speaker’s output arrives first. With conventional speakers, as you move off to either side of the centerline, the near speakers "wins" BOTH arrival time and intensity, thus the image shifts towards the near speaker, often dramatically so.
What I’m going to suggest is sometimes called "time-intensity trading", as the off-centerline listening locations which have a later arrival from one speaker compensate by having greater intensity (loudness) from that speaker.
Briefly, start with speakers which have a very uniform radiation pattern of perhaps 90 degrees wide (-6 dB at 45 degrees off-axis to either side) over most of the spectrum. Then toe them in severely, such that their axes actually criss-cross in front of the centeral "sweet spot".
For an off-centerline listener, the NEAR speaker naturally "wins" arrival time, BUT because of the aggressive toe-in and relatively narrow radiation pattern width, the FAR speaker "wins" INTENSITY!
For example, the first photo at this link is taken from a listening position which is well off to one side. As you can see, at this location you are on-axis of the far speaker but well off-axis of the near speaker. So the far speaker is actually LOUDER at the frequencies which matter most for image localization!
https://parttimeaudiophile.com/2019/06/17/new-gear-from-audiokinesis-and-resonessence-labs-t-h-e-sho...
With this configuration (and speaker type), these two localization mechanisms - arrival time and intensity - approximately offset one another, and you get an enjoyable spread of the instruments even well off the centerline like where that first photo was taken from. It’s not perfect of course, but it’s arguably about as good as far off-centerline listening is likely to get without advanced signal processing (like the Beolab 90).
The KEY to this technique working well is, the output of the near speaker must fall off SMOOTHLY and RAPIDLY as we move off-axis. In other words, this technique will not work well with most loudspeakers.
Of course the imaging will be best up and down the centerline, but elsewhere in the room the soundstage will hold up considerably better than normal. Spacing the speakers a bit wider apart than normal helps maintain soundstage width. A welcome side-effect of the speakers’ well-behaved radiation pattern is that the tonal balance holds up unusually well throughout the listening area, though a good omni will probably do better in this respect.
Here is a link to an article on the subject, I don’t know who the author is:
http://www.libinst.com/PublicArticles/Setup%20of%20WG%20Speakers.pdf
Duke