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Setting Sound Levels

Mon, 6 Oct 2008, 06:28 pm
Don Allen15 posts in thread
Has anyone actually learnt How to set up the sound levels in your theatre or is there an "expert" who says you have do do it my way and yet they cannot explain to you why they do it their way. If you can hear hiss, or noise or your speakers sound overloaded or distorted, then it is time to learn how to set up the levels in your audio desk. This article by Yamaha will explain it all, please remember to turn your amplifier gains way down before you start setting your levels. http://www.yamaha.com/yamahavgn/CDA/ContentDetail/WrappedTextDetail/0,,CNTID%25253D48551%252526CTID%25253D227500,00.html In summary: 1. Your cd player will have a nominal line output, it may be fixed at 774mV as it is not usually a 600 ohm feed, but a 10Kohm feed (domestic). 2. Set the slide fader to 0dB which is the black line at the 3/4 mark (3/4 of 1 volt is 775 mV) 3. Set the main fader to 0dB which is the black line at the 3/4 mark (3/4 of 1 volt is 775 mV) 4. Adjust the channel gain which is usually a rotary knob so you get 0VU on the desk output meter. 5. Adjust you power amp input level, usually a rotary know, for the desired sound level in the theatre. You now have the ideal compromise between best signal to noise (getting rid of the hiss) and not running out of headroom (distorting the sound coming out of the speakers. Hope this explains things and helps improve the sound in some of Perths theatres. Links: Line Level - Wikepedia http://en.wikipedia.org/wiki/Line_level

Thread (15 posts)

Don AllenMon, 6 Oct 2008, 06:28 pm
Has anyone actually learnt How to set up the sound levels in your theatre or is there an "expert" who says you have do do it my way and yet they cannot explain to you why they do it their way. If you can hear hiss, or noise or your speakers sound overloaded or distorted, then it is time to learn how to set up the levels in your audio desk. This article by Yamaha will explain it all, please remember to turn your amplifier gains way down before you start setting your levels. http://www.yamaha.com/yamahavgn/CDA/ContentDetail/WrappedTextDetail/0,,CNTID%25253D48551%252526CTID%25253D227500,00.html In summary: 1. Your cd player will have a nominal line output, it may be fixed at 774mV as it is not usually a 600 ohm feed, but a 10Kohm feed (domestic). 2. Set the slide fader to 0dB which is the black line at the 3/4 mark (3/4 of 1 volt is 775 mV) 3. Set the main fader to 0dB which is the black line at the 3/4 mark (3/4 of 1 volt is 775 mV) 4. Adjust the channel gain which is usually a rotary knob so you get 0VU on the desk output meter. 5. Adjust you power amp input level, usually a rotary know, for the desired sound level in the theatre. You now have the ideal compromise between best signal to noise (getting rid of the hiss) and not running out of headroom (distorting the sound coming out of the speakers. Hope this explains things and helps improve the sound in some of Perths theatres. Links: Line Level - Wikepedia http://en.wikipedia.org/wiki/Line_level
jeffhansenMon, 6 Oct 2008, 06:32 pm

Cheers Don. "Sound" advice

Cheers Don. "Sound" advice for us hacks out there. www.meltheco.org.au
David AshtonMon, 6 Oct 2008, 10:33 pm

I know that, however, you

I know that, however, you will not find it set that way in virtually any venue, the common setting is with the amps set at full and masters down to compensate, there was a heated debate by so-called "experts" on the "Blue-room" about this topic and it was amazing to see the total lack of understanding of the "experts".If you have other links in your chain, graphics, compressors or effects, the rule is to set their gains so that they are just below their clip point.Setting the gain structure this way will increase your signal to noise ratio considerably and as dimmer noise is the most likely source of interference in a theatre, this helps dramatically.
Walter PlingeTue, 7 Oct 2008, 09:40 am

power boxes

If you are lucky enough to have quality powered boxes with no gain control on them or unlucky enough to have "installation" amps with no gain control, the point to reduce gain is as late in the signal chain as possible. Graphics with an output gain are good for this. I've seen people trying to balance levels on the bottom few milimetres of faders.
JoeMcWed, 8 Oct 2008, 01:34 pm

Knowing next to nowt about

Knowing next to nowt about sound gear, except how to play or avoid it.
As in most theatres techies tend to rely upon the Bang Test, for the most part.
David showed us the other day, how to set the sound levels, which was great!
It always bemuses me witnessing noise boys, constantly twiddling their knobs & such during a show. Sure I realise the need to ride the desk occasionally, but bumping & griding the rotaries all the time. Is surely just for the old ego, especially when the operator is taking up valuable seating in the centre of the auditorium - which is something that gets up my nose!
Don AllenWed, 8 Oct 2008, 04:27 pm

Yes go to the Fly By Night

Yes go to the Fly By Night and watch Ric set up, takes a few hours to set up mics and DI's to the tech specs, tune to the room and set foldback levels, then he sits back with very little adjustment required because he has taken the time to set it up correctly.
TaureanWed, 8 Oct 2008, 06:38 pm

Thanks for the link

Thankyou Don, David and "Roger" for your input and advice. Having seen Ric, Martin, Dan Higgot (ESH Touring Company) and others of their ilk going through the "sound check" pre-show setup more times than I care to remember, I am one who is painfully aware of the need to keep it low on the controls.

For the record, Yes Gaafa, riding the desk is a bit of an ego trip for some Audiophiles, but as Don implied, in most cases it is not necessary if they have set their desk up correctly in the first place, but sometimes knobs just have to be twiddled.

Whilst I am here, I apologize on behalf of Audio Tech's the world over for taking up valuable seating space in the centre rear of the auditorium, but that is simply the most logical place for us to be. We need to hear what the audience hears,if not.... well we may as well not be there.

Sit us up in the Bio Box behind a glass screen and we will run your show.... but be prepared for the onslaught of unhappy patrons that complain it is too loud, too quiet, couldn't hear the vocalists over the band, couldn't hear the band over the vocalists, the telephone was too loud, the gunshot was too quiet, the thunder was unbearable, what were those strange noises that sounded like blah...blah...blah.. and so ad-infinitum.

If you want the best sound reproduction you can get, we need to be where we can hear it the best, which is in among the audience so that we are listening to whatever they are listening to and can (if we want to show off and ride the desk) make adjustments as neccessary.

"Be nice to your Tech's - or they'll turn out the lights and go home!"

NaWed, 8 Oct 2008, 07:11 pm

I've been waiting to ask...

another thread to add to the FAQ? We need more stuff there for us techies Furry puppet eyes for your next build at Puppets in Melbourne
stephendeanWed, 8 Oct 2008, 08:24 pm

A book to read

for those of you wanting to know more about live sound I suggest you read Duncan Fry's Live Sound Mixing. This is a great book by an Aussie Sound engineer. This guy is respected world wide. One thing he does say is most times you run your amps at full or maximum as the level going to each amp is controlled firstly by the mixing console, and then by graphics, compressors and final crossovers. This is how I do in my everyday job as well.
David AshtonWed, 8 Oct 2008, 10:30 pm

If he says that he is

If he says that he is wrong, and I very much doubt he did, because it is illogical, the input to the amplifier has to be balanced to the output of the previous device.A quick Google of audio gain structure will throw up scores of references, none of which will tell you to set amp gains at full. A good guide to gain structure is http://www.rane.com/note135.htm You should look at it or any of the other excellent studies, it will improve your sound.
JoeMcThu, 9 Oct 2008, 12:19 am

Graeme I think I realise

Graeme I think I realise the reason;- " I know he's audio, but wot's he doing there?"
With audio personally, I prefer to 'set & forget! - in the words of Francis Reid;-
"Hear the light & see the sound"
lets face it;-
If audio techs could count past 1 - 2 -?
They'd all be electricians!
The same when setting up bands, why go to all that palaver? 
"If one wants to know about EQ'n the venue - just consult the Drummer!"
As this all lovable ongoing banter; -
Bless all the Noi's Boi's 
'n their cotton wotknots?
[this is a great thread;-
I now feel confident enough to  darn wind socks & sew up pressure pockets!]
Walter PlingeThu, 9 Oct 2008, 04:54 pm

Duncan Fry's Live Sound Mixing

Dunc, bless his cotton socks, is writing about mixing bands mainly. A very diferent proposition to audio for theatre, where silence is just if not more important than noise. Though even then there are some types of music gigs where I would knock some gain of at the amps to get better levels going through the desk. If an amp wasn't meant to have a gain control, it wouldn't have a gain control. If its there you are meant to be able to use it.
Walter PlingeWed, 19 Nov 2008, 08:02 pm

Gaffa 1,2,3,4,5,6,8,9,10

..... HMMMMMM ..... is that what you really think of us "noise boy's" Gaffa Luv, Andrew Foster Head Of Sound. Priscilla On Stage The Musical ;)
JoeMcWed, 19 Nov 2008, 11:59 pm

Affectionate techie banter

1 to 10 very impressive, your have obviously gone digital - Affectionate techie banter Andrew! Aptly descriptive &/or in dogegorising as in one being a Luvvie, twirly or a spiv!

Chookas

Walter PlingeThu, 20 Nov 2008, 05:01 pm

Figured...

Figured that, but just couldn't pass up the opportunity to type to ten for you. All the best.
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