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Beyond Stereo

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Category: General
Forum Name: Advanced Discussion
Forum Description: Advanced discussion area for higher lifeforms
Printed Date: 18 August 2022 at 2:06am
Software Version: Web Wiz Forums 12.05 -

Topic: Beyond Stereo
Posted By: opus jody
Subject: Beyond Stereo
Date Posted: 08 June 2022 at 12:15pm
Greetings, speaker planners.
Percieved 3d sound stage, when 2 stereo sound sources make something like a triangle with the listening position. Great for hifi, but completely loses it on large stages, or wide, shallow stages, as described pretty well here:

So, I had a little 8m x 15m marquee, at Equinox festival a few years back. All good, except we had to fire the music side ways, so by the time a DJ booth had been built against the long side, there was a tiny dance space in the centre, where it would sound great (with stereo stacks) and two huge areas at each end that would have been a diabolical catastrophe of LF phase cancellation, and mucked up stereo imagin in the mid-tops.
I had 8x double 15 and 6x 2 way tops.
It was a small tent, so I split the rig into 4 stacks of 2 subs each, and the 6 tops arranged like this:
there would be 3 separate 'zones' of proper stereo.
With all the tops hard-angled over 45deg, I noticed that further back,  facing each of the two centre stacks, you also get a perfect stereo zone between stacks 1 & 3, and 2 & 4, and even further back, you get another perfect stereo point in the centre, hearing only stacks 1 & 4.
Stereo everywhere!! With the added bonus, that with just one top left, and one top right audible (on axis) heard from anywhere, there was no discernable comb filtering.

So, does it work bigger?, Bearded Theory, a 1200+ppl dance tent, with bands.
A large 2 pole big top, again sideways on, with the stage taking up most of the space to the 2 king poles, and the good bit (middle) shrunk even further by the raised FOH possition
I had already tried various set ups to avoid the inevitable 'awesome in the middle, but shit on the sides' effect.
Stereo rig - failed - no bass at the sides
mono central sub - failed - still not enough bass at the sides
So, triple stereo.
4 stacks of 2 x 218 (reflex) and 2 x 215 (reflex) with the same top box arrangement as above (L...RL...RL...R) which neatly put the FOH position on the apex, with perfect stereo between stacks1 & 4.
(The bass in this pic is not correct. Shown is 2 x 215, as I did at Equiniox above, not the 4 subs per stack I used)

This year we did the same, but with all 215's (4 per stack)
It was immediately apparent that as people entered the space, they didn't all head for the 'schweet schpot', but spread really evenly throughout the venue, and the bunch of pint-in-hand audiophiles that normally hang out in the middle, were instead evenly split between the two middle sweet spots, and right at the back, in front of the FOH sweet spot.
It's a winning set up! and no extra processing required.
If you get a wide venue, and have enough bass, & 6 identical tops, then try it!

Bearded Theory 2022
(Credit to Norty 303 & crew for the aMAZING lasers n shit)

This year, at Glastonbury, Glade Dome (in the area where Glade Main usually goes) we have a similar wide & shallow dance floor, so we're going to try the same system.
I suspect it might get a bit smeary outside the dance floor, but should sound super tight, no combing, and full stereo almost everywhere within the area.
Come & check it out. ;)

And for coinvenient reference, we're right next to the 'best sound system on site' so you'll be able to hear if a bunch of speakerplans hippies (and Lee) can get anywhere close. Clown

Improvised Hardware Music

Posted By: 4D
Date Posted: 08 June 2022 at 12:22pm
Yes indeed look forward to coffee a catch up & a listen.. :)

DMZ. "The bass was intense. Girls were literally running up to stand next to the subs"

Posted By: toastyghost
Date Posted: 08 June 2022 at 1:00pm
Nice idea! It’s not a million miles away from how L-ISA works, with vector-based amplitude panning between multiple coplanar identical sources.

If you can stretch to up to 7 ‘stacks’, ideally with a flown pair above the centre stage, then you can get really good results with various amounts of panning of ‘stereo’ sources to each of them. Either via desk or LMS matrices, although the former is preferable if you've got live music sources. 'Locating' a performer to the speakers near to them is much more 'natural' than traditional stereo.

The maths is relatively simple, just needs a tape measure and some inverse distance maths.

Funnily enough, it's also closer to the original Blumlein concept of 'stereo' anyway!

Posted By: opus jody
Date Posted: 08 June 2022 at 3:06pm
Another brucy bonus, the only two main bass dead spots are at each end of the FOH decking, so when the noise police turn up with their measurement mics, guess where we put them? Big smile 6dB extra for free.

Improvised Hardware Music

Posted By: James Tengo
Date Posted: 08 June 2022 at 3:27pm
We had d&b's take on 3D audio (Soundscape) on the April Groove Armada tour, 5 hangs of KSL across the front of the stage and 32 boxes of Y spread around the auditorium

Posted By: fatfreddiescat
Date Posted: 08 June 2022 at 5:02pm
Jody, all you say is bang on, comb filtering was all but inaudible, big wide sweet areas and less obviuos bass power allies, also sounding smooth behind the stacks of yours, was altogether a bloody good effort by allThumbs Up
Best sound on site hands down.

Posted By: kipman725
Date Posted: 09 June 2022 at 4:40pm
Hi Jody I was there at Bearded and your tent was one of the best sounding on site particularly your sub setup was working well in the tent.  As is often the case at these events the main stage setup was brain dead.  As you say quite a tricky tent to deal with if you can't have a conventional front to back arrangement.  I did however think that the sound was a bit strange in many places in the tent, particularly in the overlap region of the two front stacks.  My initial impression was the splay angle was totally wrong on the tops before the stereo concept was explained to me (sounded like bits of the spectrum was missing).  As you say though it gave more 'zones' in the tent with acceptable sound so perhaps it was the best possible compromise.

Posted By: opus jody
Date Posted: 09 June 2022 at 9:24pm
Hi. Sounds like you might have been in the central spot, that would normally be the best listening position on any other set up. That is one of the squiffy bits. If you had moved forward, between the 2 central tops, you would have got the full mosh pit experience, and if you'd moved back to FOH you would have the outer 2 tops, and if you'd moved either way sideways, directly in front of a central stack, you would have had left & right from stacks 1 & 3, or 2 & 4, but yeah, thats not the best listening position any more.

Improvised Hardware Music

Posted By: fatfreddiescat
Date Posted: 09 June 2022 at 9:50pm
I'm not so sure it was your system set up that caused that, just also happens to be around about where the reflections of of the roof of the tent would be hitting.

Posted By: 4D
Date Posted: 29 June 2022 at 9:52am
Originally posted by 4D 4D wrote:

Yes indeed look forward to coffee a catch up & a listen.. :)

Good to catch up with you and the inimitable James Folkes albeit briefly..   Came down later for a listen.  Gosh it was busy  

Sounded superb.    

DMZ. "The bass was intense. Girls were literally running up to stand next to the subs"

Posted By: opus jody
Date Posted: 01 July 2022 at 5:36pm
Great to see you too. It's been ages!

Yes, that was fun.
Getting covid wasn't though.

Quite a few compromises though.
The main ones were 3.5m gap between barriers & speakers, meant that the central stacks had to go inside the dome, so they were too close to each other (for proper 6-point stereo)
and the FOH position was so far back, that the angle of the outer tops was too deep, or FOH wouldn't have been able to hear on-axis, but it still worked pretty well.

Tops angled down a touch did a great job of keeping the sound contained within the space. Noise police pretty much left us alone. (Just a couple of dB off late at night)

There was a funny moment. Noise police wanted the rapper turned down (no problem, lol)
Then rapper wanted it up. (ok, a little bit)
Then noise police turned up wanting him down again, so I introduced them to eachother, and left them to it.
The noise guy never came back, hahaha" rel="nofollow - Hippo Sound System

Back to bed. Covid sucks. :(

Improvised Hardware Music

Posted By: jacethebase
Date Posted: 01 July 2022 at 6:02pm
Originally posted by opus jody opus jody wrote:

Great to see you too. It's been ages!

There was a funny moment. Noise police wanted the rapper turned down (no problem, lol)
Then rapper wanted it up. (ok, a little bit)
Then noise police turned up wanting him down again, so I introduced them to eachother, and left them to it.
The noise guy never came back, hahaha

That is fantastic work!


Posted By: Xoc1
Date Posted: 01 July 2022 at 8:42pm

Another Angle showing the Amp stacks -Typical PA nurd Photo - Heavy stuff!

Posted By: Xoc1
Date Posted: 01 July 2022 at 8:56pm
Found Another Smile

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