Author Topic: delay on FOH  (Read 487 times)

Ram

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delay on FOH
« on: May 20, 2017, 12:38:12 AM »
On a front of the house for a large audience - I have 2 FOH speakers close to the stage and 2 FOH speakers 60 feet away into the audience.
I guess the signal to the farther speakers should be 'delayed'.
From DL1608, how  do I send the outputs to these speakers?
If I send the mains (Left Right) to the farther speaker with the delay, how do I send the same main to the close speakers without delay.
Should I use 2 auxes with unity levels and post fader (to the closer speakers?)
Or is there a better way to feed the four speakers?

Thanks.
-Ram

shufflebeat

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Re: delay on FOH
« Reply #1 on: May 20, 2017, 02:13:34 AM »
Hi, Ram.

A few background questions first:

Do you run your main speakers in mono or stereo?
Do you intend to run your satellite (room) speakers in mono or stereo?
Do you have bass bins and tops or just full range cabs?
How big is your PA?
Do you intend to run a full range signal o your satellites or just top end?
Are you using active or passive speakers?

The answers don't radically alter any suggestions but they might be relevant in some way. Others might think of more questions.

Ram

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Re: delay on FOH
« Reply #2 on: May 20, 2017, 02:56:02 AM »
>>Do you run your main speakers in mono or stereo?
mono

>>Do you intend to run your satellite (room) speakers in mono or stereo?
mono

>>Do you have bass bins and tops or just full range cabs?
just full range - no bass bins

>>How big is your PA?
4 Mackie srm450 speakers

>>Do you intend to run a full range signal o your satellites or just top end?
full range

>>Are you using active or passive speakers?
active

shufflebeat

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Re: delay on FOH
« Reply #3 on: May 21, 2017, 10:30:12 AM »
Ok.

There are several ways to actually hook up the system, hereís one:

Main outs (L/R) go to your main speakers Aux 5&6 (could be any 2 but letís use 5&6) to satellite speakers (delay tower/stack) Link auxs 5&6 for stereo use (now Iíll refer to 5&6 as 5/6).

Now you have some decisions to make at the aux 5/6 master section:

1) Pre DSP - individual signals going to satellites will not reflect that channelís EQ and compression - not recommended except in specific circumstances, not yours.
2) Pre fader - signals reflect EQ and compression settings but are not controlled by the FOH fader settings - handy if you want the satellites to Ďtop upí sounds that are not carrying to the back of the room, making a separate mix for satellites which will not change as you adjust FOH.
3) Post fader - signals to satellites reflect channel EQ and compression settings and are adjusted with channel FOH faders. You can still do the Ďtop upí by adjusting the 5/6 channel faders appropriately or just leave them at 0dB so the mix at 5/6 is the same as FOH (assuming the same master EQ settings).

Option 3 is probably the most suitable but Iím sure you can think of situations where the others might be useful.

Definitely use ďL/R muteĒ so that the audience at the back of the room canít hear the band chat through a mic you think has been muted.

You can choose for the satellites to reflect FOH pan settings but this is not relevant if youíre running in mono.

You could do all this on one aux but that would require you to run an XLR link cable between the satellites which might not be practical if they are on opposite sides of the venue. I have 2 super-long XLRs (XXXLRs?) for such purposes.

Now if you go to the 5/6 master compression page, at the bottom is the delay setting. If your speakers are all in a line, (ie. satellites are off to the side in a wide room) then this gets complicated and you might cause as many problems as you solve. If your satellites are in front of the FOH down a narrow room then itís simpler, estimate the distance between FOH and satellites and type it in. You may want to play some music through both FOH and satellites and experiment with delay times until the musical image becomes Ďsolidí. Itís fun.

Donít worry about messing with temperature unless you have a medical qualification.
« Last Edit: May 21, 2017, 10:35:59 AM by shufflebeat »

Rdmitch

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Re: delay on FOH
« Reply #4 on: May 21, 2017, 11:49:48 AM »
Can you clarify a dumb question for me regarding delay since this thread is on the topic.

If the satellite speakers are in the back, or halfway back of a deep room, and sound from the stage takes a
microsecond to get back there....why would we ADD additional delay ?
I would think adding delay to speakers in the back would put them even more out of sync to the stage sounds.
What concept here am I just not understanding?
Please help me understand this better.
Your never to old to learn something stupid

shufflebeat

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Re: delay on FOH
« Reply #5 on: May 21, 2017, 12:20:17 PM »
...because electricity travels down cables (to satellites) quicker than sound travels through air from FOH to the back of the room (including to those standing beside satellites).

Delay is applied to satellites to allow the sound from FOH to catch up.
« Last Edit: May 21, 2017, 12:23:32 PM by shufflebeat »

Rdmitch

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Re: delay on FOH
« Reply #6 on: May 21, 2017, 02:33:14 PM »
Got it and think I'm understanding the concept better.

I was simply thinking that in a venue deep enough to need satellites, people in the back would not hear any
stage sound, so why delay the satellites.
I guess the concept is the relationship of sound traveling thru air from the FOH spkrs being more in sync
with the satellites and I can see that as a valid reason for the delay.






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shufflebeat

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Re: delay on FOH
« Reply #7 on: May 21, 2017, 04:09:21 PM »
As we're talking here it's all a bit theoretical and open to misunderstanding. When you hear it in real life it's totally obvious and relatively simple, although people have written large books on the underlying theory and related topics. At a gig it just sounds better.

I've been a "guest" tech at a regular folk gig at which I've previously been a member of the audience. I can hear the effects of non-delayed satellites; phasing problems and rhythmic conflicts. Everyone can hear them but few people know they can hear them because the brain filters out the effects so the music makes sense.

When I do the gig I delay the sats, EQ them to allow for FOH and concentrate on a decent mix. People are amazed and very complimentary, even though they have a great, and deserved, loyalty to the regular tech.

When I demonstrated the difference to the promoter it was in an empty room so reflections meant the difference wasn't quite so apparent and he was a bit sceptical but the audience were convinced, even though they didn't know what of.

Weogo

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Re: delay on FOH
« Reply #8 on: May 22, 2017, 01:21:01 AM »
Hi Ram,

Another approach:
Un-assign all channels from the L/R master, and do assign them to Groups 1 & 2.
Hard-pan the Group-1 master to the left, hard pan Group-2 to right, and send Groups 1 & 2 to the L/R master. 
Set the Group1 & 2 masters to nominal 0.
Turn on delay for only Group-2.  Use an XLR-Y cable out of the Left master output to your front speakers, and an XLR-Y out of Right for your delay-fills.

Now your L/R master is your overall level control.
You can fine-tune the front/back levels with the Group 1 & 2 masters.
If you want a little more of channel-2 vocal in the rear speakers relative to the front, simply pan the channel a little to the right.
I use this setup in a venue with a mono center cluster and front corner-fills.(And no delay.)
All 6 Auxes are still available for monitor mixes, subwoofer send, two recording mixes, etc.

Properly set the level on the delay-fills and they will nearly disappear.
You may have someone tell you they aren't turned on.
When you turn off the fronts, they will still definitely hear the delays.

Delay-fills are a compromise.  More sound sources can mean less intelligibility, because of more sound arrival times.
But properly used, they can add intelligibility, without turning up front speakers.
If possible, sometimes a better approach is getting front speakers up high enough to not blast folks at the front of the hall, and tilting the speakers down to reach the back of the hall.

Another delay-fill issue is there may be significant low-mid frequencies coming off the back of the speakers and going toward the stage.
Sometimes you might want to cut some lows out of delay-fills.
 
I use delay-fills at more than 50% of my gigs.

Thanks and good health,  Weogo

Ram

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Re: delay on FOH
« Reply #9 on: May 22, 2017, 03:38:08 AM »
Thank you Rdmitch and Weogo!
I know I will learn a lot by asking here and I certainly did!
I will use Rdmitch's solution since it is easy for me to do.
-Ram

shufflebeat

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Re: delay on FOH
« Reply #10 on: May 22, 2017, 10:27:13 AM »
 Hey, Weogo, I like the sound of that, for the price of  a two splitter cables you're reclaiming two aux sends. How are you delaying group 2?

I'm on MF4.6 and there are only delays on the aux sends and L/R (linked for stereo).

Weogo

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Re: delay on FOH
« Reply #11 on: May 22, 2017, 01:48:20 PM »
Hi Shufflebeat,

Oops! 
Sorry, that is a patching setup I use in a venue that still has a Yamaha 01V96, which has delay on Groups.
The 01V96 even has separate, independent delays on the L/R masters.

There is a way to do this with only one Aux.
Make Aux-6 post-fade, apply and use for delay, Label BACK.
Use an XLR-Y cable out out of Aux-6 for two delay-fill speakers.
Label LR Master FRONT.  You can still do 'stereo' LR.
Label VCA-1 HOUSE for master level control, assign LR and Aux6 to VCA-1.
You still have independent level of Front and Back.

Thanks and good health,  Weogo

shufflebeat

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Re: delay on FOH
« Reply #12 on: May 22, 2017, 05:02:46 PM »
Ah, you piqued my tech-itch there - got it.

I should have considered the use of a Y-splitter to accommodate 2 speakers in mono - otherwise as you were.

Greg C.

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Re: delay on FOH
« Reply #13 on: May 23, 2017, 07:07:46 PM »
As far as the delay goes, the ballpark is ~1ms per foot. So if your fills are about 60 feet from the mains, then you'll need about a 60ms delay to line them up.
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Greg C.

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Re: delay on FOH
« Reply #14 on: May 23, 2017, 07:15:17 PM »
Got it and think I'm understanding the concept better.

I was simply thinking that in a venue deep enough to need satellites, people in the back would not hear any
stage sound, so why delay the satellites.
I guess the concept is the relationship of sound traveling thru air from the FOH spkrs being more in sync
with the satellites and I can see that as a valid reason for the delay.

Sound is pretty slow. It travels about 1 millisecond per foot (actually a tiny bit faster than that, but it's close enough). So if you're 100 feet away from the stage, that's a 100ms of travel time until it hits your ears, or 1/10 of second. If you need rear fills to help get PA to the folks at the back of the room without killing people in front with excessive mains levels & you don't add the properly delay, the folks that can here the fills will hear an echo and it will smear intelligibility noticeably. This is true of smaller venues and big ones like say the Coachella festival outdoors where they run line array towers on delay.

The phenomena of the speed of sound is also interesting in that if you're shot by sniper with a high power rifle, the bullet will hit you before you hear the shot since those type of rounds are hypersonic - faster than the speed of sound ;)
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