Radio Mic Delay trick?

[sammfinn]

Hi,

 

I had a conversation with another theatre sound designer a while ago about omni radio mics and his methods on delaying them. He mentioned something he had seen someone do previously, apparently by delaying an omni mic (headworn) by 0.7 ms (?) it created a kind of mind trick that tricked the brain into thinking that the sound was coming from the person as opposed to the speakers on the pros. I imagine there is a lot more to it than this, but I was wondering if anyone had a system for implementing such a method, or if it even exists?!

 

I am using 7 Sennheiser MKE mic heads worn in the hairline, on a stage thats about 14 metres wide and goes about 7 metres deep from the pros line, with a L C R FOH system. There are some musical numbers, but I am only concerned with using the method during dialogue in an attempt to localise the actors voices... any advice on this would be greatly appreciated, or any other methods for achieving the same effect.

 

Thanks

[david.elsbury]

1ms = 1ft (as a general starting point) . So 0.7 Ms is tiny. I believe the brain only starts to become aware of a delay at a much higher amount (unsure exact number - someone??)

 

Anyway, how far are your actors from the front row? How far are your speakers from the front row? You might already have your delay, by virtue of speaker distance.

 

At the end of the day, does it sound good? Are you happy with the sound? That's all that matters, not a bunch of numbers :)

 

David

[MarkPAman]

It's called the Haas effect.

 

A lot of digital desks just let you set delay on input, and/or output as you wish. With an analogue desk, you'd require a delay unit of some kind. Or there may be a suitable delay in a speaker management unit if you have one.

[Ross]

Hi Sammfinn,

I think the study of the way your brain combines sound and vision is called psychoacoustics http://scholar.google.co.uk/scholar?q=acoustics+and+psychoacoustics

I've only dipped my toe in this with discussions about speaker placement when people want them to be tidier rather sound better but there is a whole bunch of reading depending on what level you feel comfortable with.

All the best,

Ross

[sammfinn]

Haas effect! thats the ticket. I have an X32 (dont grumble!) so all the delays will be plotted on the mic inputs within scenes, during the tech.

 

Cheers David, and of course its what sounds good regardless of anything else! I just wondered if there was a quick fix formula, but as with many things in this job its about finding methods that work for you. There is an apron to the stage, which is about 2 metres downstage of the pros line, and the front row sits right in front of that, and the cast come right downstage as well as some being upstage at the same time... So it could be interesting!! http://www.blue-room.org.uk/public/style_emoticons/default/dry.gif

 

Thanks Ross, I will have a look into that.

 

Thanks,

Sam

[J Pearce]

You can also set delays on each output and bus on the X32, as I am doing this week.

It can help to pull the image back down, but there is a limit to how much louder the reproduced sound can be compared to the natural acoustic sound before the trick fails.

 

Typically the brain can cope with up to 30ms between sounds and still merge them. I tend to go for true time align (1ms per ft) then add 10ms for image shift purposes.

 

There are some very clever systems out there that can track location and dynamically adjust the delay to match the aural location. Pricey and complicated though!

[Simon Lewis]

There are a number of effects at play (including Haas's) but this situation is more correctly attributed to Cremer and later Wallach and his 'law of the first wavefront' or Precedence Effect.

 

Basically, within given arrival times your ear brain mechanism attributes or localises the sound source to the first arriving wavefront. This is why you can delay teh reinforced sound to help give the illusion that the sound source is the actor on stage, not the loudspeaker to the side.

 

Jon mentions an automated system... have a look at Outboard Electronic's TiMax and Track the Actors systems.

[Bobbsy]

Practical use: the delay is actually just over 1ms per foot of difference between the actors' positions and where the FOH stacks are with reference to the audience. Clearly, without expensive auto systems that give a stunning sound stage, you can only work to an average. Plonk your actors somewhere mid stage then dial in a starting point using the 1ms per foot guide... Then very slowly dial in a bit more delay on each channel. You'll be amazed to hear the sound jump from the speakers to the actors' mouths.

 

Clearly this works less well as the venue size grows and you lose the direct sound, but. For an average venue it works a treat. I've been asked more than once on well amplified shows. If the PA had failed because, though they heard fine, nothing seemed to come from the speakers.

[Simon Lewis]

...I've been asked more than once on well amplified shows. If the PA had failed because, though they heard fine, nothing seemed to come from the speakers.

 

I know of installers who have correctly set up delays for distributed church sound systems, but have been told by the minister, "I'm not paying for loudspeakers I cannot hear.... switch them back on again!".

[sleah]

Funny how the mind plays tricks with you.

In theory, you shouldn't need a delay as the visual cue of someone speaking will arrive at your brain before the sound, so if you are closer to the speakers, then any delay to match the speed of the sound exiting the actors mouth and arriving at your brain ought to sound awful... but somehow your brain expects the sound to arrive after the visual so if it arrives at pretty much the same time, it gets all confused. So delaying amplified sound to make it arrive at the same time as the direct sound works well for your brain, even though it is slightly after the visual cue of the mouth moving! :blink:

 

I think my head is going to explode!!!!! :** laughs out loud **: :** laughs out loud **:

 

To save me making like a mole to go dig out the manual (and being a lazy get), can anyone tell me off the top of their head (or through their keyboard) if an Alesis Midiverb 4 can do a suitable delay?

 

I fancy a tinker :D

[Bobbsy]

...I've been asked more than once on well amplified shows. If the PA had failed because, though they heard fine, nothing seemed to come from the speakers.

 

I know of installers who have correctly set up delays for distributed church sound systems, but have been told by the minister, "I'm not paying for loudspeakers I cannot hear.... switch them back on again!".

 

Not churches exactly but been there, done that.

 

...and (I think) the best back handed compliment I ever received was the mother of an actress (who shall go un-named as she has enough career to turn up on Google) that it was too bad I made her daughter mime to recordings because the sound was too good to be live. I was using something like 22 orchestra mics and 18 RF lavs at the time. To her credit, the actress set her mother straight and sent me a nice thank you note.