It's an expansion of the omnis to 1 meter, with a commensurate expansion of the subcards to 28" (24" for cards; 20" for supercards). Both pairs then panned-in just enough to provide a solid center (considerably less than the middle pair of the four mic Decca Tree; for my taste, ~80-81% compared to the 50% stated for the 4-mic Tree).

My reason for trying this is that I'm always looking for a main array that sounds equally pleasing on 'phones and loudspeakers. The Onno double AB does this beautifully, but there are times the unique properties of the Faulkner-4 are preferred. As lovely as the 26" omni spacing sounds on speakers, I've always found it to feel a bit phasey and a touch weak in the center on 'phones. Panning-in a touch helps, but then it begins to sound a bit narrow on speakers.

One meter spacing with mild in-panning addresses both issues; sounds more natural and comfortable on 'phones and still sounds nice and lush on loudspeakers due the significant increase in Interchannel Time Difference relative to 26" spacing.

I've found it's best to set the degree of in-panning while monitoring with 'phones rather than speakers. One can tell immediately when there starts to be too much build up in the middle.

I would never claim to have 'bettered' an idea of @ TonyF 's, I just find for my own taste, that I enjoy this more on HP listening, and it doesn't compromise speaker reproduction at all, in fact it has more 'bloom' (especially at low frequencies) due to the increased ITD.

Have you tried it on a variety of sized ensembles...I'm guessing it might lend itself better to a larger, wider orchestra rather than a chamber group ?

Does it still tend to sound 'furry' at equivalence-gain (ie when the 2 pairs are mixed at equal level, thus leading to favour one pair over the other by 6-9dB, to avoid this phenomenon) ?

So far, I've only used on orchestra.

Wider spacing would have no effect on the mix balances.

Measured as only a North American could. It's OK - as a Canadian I am SAE/Imperial/Metric schizophrenic too.
For our friends in the rest of the world, that's: 51 cm for supercardioid, 61 cm for cardioid, and 71 cm for subcardiod. Or you could probably round it to 50/60/70 centimetres. Of course, the metre spacing of the omnis is 100 cm...the beauty of a decimal-based system. Oh yeah, there's two spelling systems in English too. Metres and meters. Or is that just English and American preferences? Is American a language? Some think so.

I think the 'problem' of mixing the two pairs at equal level is rather exaggerated.

When I first began experimenting with the dual pair array, I listened carefully and extensively for any change in timbre when the two pairs were at equal level - I would characterize it as 'barely audible'; certainly not harsh, distorted or 'furry', only 'sub-optimal' at worst.

It's well to remember that with the subcard pair in the middle, the distance between the two left mics (and the two right) is only about 4"; a little over half the distance of an ORTF pair, which is widely considered to have good mono compatibility (the two mics mixed at equal level). Therefore with the four-mic pairs at equal level there will only be about half as much combing as ORTF summed to mono, and begins at about an octave higher (and that top octave between 10k and 20k isn't even audible to most males over 30).

Not to mention the 'on paper' combing that the Decca Tree is certainly producing, and even 'worse', the Onno Pipe, Onno Bar, Double AB (whatever one chooses to call it), where each channel is getting two mics a good 9' apart summed at equal level! Yet both these arrays are widely admired for their actual sound quality.

As always, better to trust one's ears more than the numbers and theories.

It’s probably not so much an adverse phase interaction between the two mic pairs as a clash of stereo width pictures not matching between them.

If one compares the ‘numbers’ (level difference, stereo recording angle) of a comparison (pics below) between the standard omni 67cm and sub-cardioid 47cm spacings…the differences are shown. One may argue with Sengpiel’s measurements, so it would be interesting to compare them with others’ similar charts eg Williams, Schoeps.

I hear a ‘fuzzing’ when both pairs (of 47/67cms) have an equal contribution to the blend, which is alleviated when one or the other pair dominates by more than 6dB

If it bother thee, simply widen the subcards a bit till they match . . .

TonyF himself has described the middle spacing as "around 47cm...". I seriously doubt that minor differences are really audible.

Precise match-up would vary depending on the actual pattern of the subcards in use (there's no 'industry standard'). I haven't found that precise match up is really that important in actual use, and have never heard the 'fuzzing' you have.

Awhile ago I went back and collected (I think) all of Tony's posts here about the array, and there were none about an equal mix sounding bad; there was indeed only two comments about the mix:
1. "..usually end up with one pair dominating by 6dB."
2. A comment about an M 50-like mix: "The overall color with the omnis at -6dB is not so different from the M50's (although a bit drier)..."

…and thus, with your enhanced 1.0 metre omnis/0.71 sub-cardioids (both pairs with 90 degrees angular separation). Pictorially the images show a stretched stereo picture, with bunching of material in either speaker (and perhaps a ‘thin’ centre-fill ?) How’s your experience of this wider pairs array ?

You’re right about there not being a ‘standard’ sub-cardioid pattern…it’s yet another wild-card variable in any of these measurement approaches

Not sure what you're asking; the 'stretched stereo picture' is filled-in by the in-panning (same reason the main pair of the four-mic Decca Tree is panned-in.); something the Sengpiel can't show you - gotta use your ears.

What's "'thin' centre-fill"?

I think you just need to try it, no?

Yes, using one’s ears, rather than graph plots and tables, is the way to go….and ideally those ears informed by speaker vs output rather than headphones, as the latter can both exaggerate and hide phase and width issues. A thin centre fill is what the centre mic in a 3/5 mic Decca Tree is aimed at avoiding

I've never heard a 'thin center' in any of the work that Kenneth Wilkinson and John Dunkerley did with the four-mic Tree.

The 4 mic tree uses a smaller spacing for the centre pair (36”/91cm) than the centre-rear pair of the trio-Tree, plus panning-in, ensures a solid centre comparable to that of the 3/5 Tree.

The Dunkerley et al book states (on the 4 mic Tree): ‘It is a much more difficult technique to get right, as the spacing of the microphones is critical, but it can give a wonderful clarity to the result, particularly at the lower end of the frequency range’

I’d been using a 4 mic tree for many years before I even knew it had been a Decca invention ( ‘main pair plus outrigger’ arrays had been in use with Telarc, among others since the late 1970’s) …and experimenting with the width of the centre pair, as well as that of the outriggers, gave good insights.

I’m happy to give orthodoxy, such as the Decca Book and Richard King’s writings, star-billing, as a prelude to my own adaptations according to hall size, stage width, furnishings and wall treatments, ceiling height etc

Christian Amonson’s OCCO (and friends) document is a good summary of the 4 mics on a bar landscape, and introduces a few new contenders….such as Marc Aubort’s OOOO….that I wasn’t previously aware of.

In an associated document, I think Christian refers to this:

“Four Across the Front”
FOUR MICS, EVENLY SPACED ACROSS THE STAGE.

Like “three across” the front, the primary problem with this approach is that there is no definitive stereo image.

The two mics near the center are too far apart to be correlated, and the mics on the outside stretch the image even further. Even if the center mics are panned in some, the mics still don’t have enough information to properly recreate the sound of the space and ensemble. Without a true main pair, the mix will always sound “assembled”.

The main engineer who used this technique also used it very low and close to the band, creating a very uneven rendering that favored the downstage player”

https://www.seeingsound.com/occo-ste...ding-technique

Indeed, 3' is the max spacing I would be comfortable with filling the middle by in-panning.

As wonderful as Aubort's recordings are in every other respect, I don't enjoy the hole-in-the-middle they have (main pair many feet apart), and find them more pleasant to listen to with a little in-panning, especially with headphone listening.

__________

The article is a bit inaccurate on two things:

1. Aubort didn't use "OOOO" that frequently; he's said he only adds the outer pair when the orchestra is unusually large. Many of the Slatkin/St.Louis sessions were a simple main pair, plus very few spots, and a hall ambience pair. "...basically we have a two microphone approach." ('Studio Sound' magazine, Oct '81)

2. Using the term "OSSO" for Faulkner's array is not quite right; he's often used it with regular cardioids, such as Rode NT6 ("...I have been happiest using subcardioids..."). He's also said that directionals of any pattern (even up to figure-8) can be used, depending on the situation. Perhaps a better moniker would be "ODDO".

Thank you for that clarification M50k….instead of landing on this thread I should have posted to an earlier one which raised the same issues, and to which you’d replied some months ago ie:

boojum/jnorman array

"...so I picked this one at random... because it's generically about cabling for a multi-mic array, rather than about the mic deployment (spacings, directional characteristics etc) per se, I hope that's ok ?"

Might as well - there's been zero interest in the original topic . . .

Happy New Year studer58. This might have been the more appropriate thread to hijack:Faulkner array and insta-snake in action
That said, I have a hard time imagining more than four mics on a single bar but YMMV.

Thanks for locating that thread Jim...yes, you're right, it's more relevant to my posting than this one, so I'll terminate/repost to migrate it across...maybe our posts here will give this thread a bump ?
As for the 2 unused channels...maybe aim a directional pair backwards, just for 'additional mix options' ?