In the world of Studio Recording in particular you will hear and read about an issue called sound card latency.  Truth is if we are using a computer system and sound cue software then we are going to find sound card latency is an issue for us too.

A Difference In Time – Sound Card Latency

As a special effect delay can be extremely valuable – ask any guitarist.  In fact it is responsible to a large extent for effects like phasing and flanging too.  However…  Uncontrolled, unwanted delay destroys our timing, sound quality and the overall value of our sound cues. Latency, if you’ve not met it before, refers to how a given sound file plays back (for our purposes in live theatre) and whether or not there is a small delay compared to when we start the audio file playing and when the computer actually plays it.  It stems from the lag between a number of pieces of hardware we employ such as our CPU, Harddrive, RAM and most importantly with audio – our Sound Cards.

Start With A Quality Sound Card

That “on board” sound card that came with your computer or cheapy USB sound card you bought for a steal on e-Bay do not a Quality Sound Card make.  They may be passable for your Aunt Mary to organize her iTunes collection or for Junior to play the latest version of his first person game Grand Theft Thomas The Tank Engine, but it’s going to bite you if you’re serious about working with sound cues in a live theatre production.  Beyond the lack of frequency response (i.e. Specifications on Sound Card Box may appear better than reality) their inability to handle rapid number crunching – which is at the end of the day what a sound card does – is not up to the professional rigours necessitated by theatre productions.  So starting with a quality sound card – there are many to choose from including semi-pro and pro that will work beautifully – is going to really make a difference to latency in your projects when playing back sound cues.

ASIO And Windows Core Audio

With Windows Vista and the more recent Windows 7 Microsoft completely overhauled it’s code in terms of how audio and video are handled.  So much so that compared to Windows XP and before on Vista and Windows 7 you can just about get away with murder when it comes to the problems Windows machines in particular used to face with latency.  In fact some people will find they can just about get away without using third party software tools like ASIO – just about… At this point I should mention that I’m referring to Steinberg ASIO sound driver software and not ASIO the Australian equivalent of the CIA…  ASIO drivers do a great deal to tackle the latency issue with sound cards.  Some sound cards support ASIO out of the box, others need coaxing and some others will work fine with ASIO4All. So if you’ve never done so it may be worthwhile taking a closer look at ASIO.  Keep in mind, at all times however, that messing with sound drivers can be an endless source of fatal errors in computers, sometimes even leading to a reboot or – horror of horrors – a reboot loop where you never get the computer to load Windows. N.B.  Recent versions of Windows have gone a long way to address this.

Basic Technical Definition of Latency

• So if latency is the time difference between input and output of any theatre sound cue computer system  then its fair to say the cause is mathematical/algorithmic issues and by mechanical/physical procedures that occur mostly in software and A/D and D/A converters, and when hard drives are used.  Like I said – basic but technical.
• Latency literally means the build up of delays in an audio signal as it passes through the audio interface.
• Latency is measured in milliseconds. There is input latency, output latency and round trip latency.
• You get latency when you monitor an audio signal through a computers signal chain.
• If you ever heard a delay in hearing sound when pressing a play button on a computer audio software program then you have probably experienced latency.
• You can also get latency form using effects (VST’s / DX’s) with hidden buffers. These effects are CPU intensive and should really be restricted to being used in the final signal chain of a sound cue project whenever possible.
• You experience latency if your ASIO buffers are set to high or your WDM latency is set to high.

Generalized Solutions

I say “generalized” because really it comes down to experience and familiarity with equipment.  Get to know your gear and it’s limitations.

• “Round Trip Latency” – should be less than 11 milliseconds for best results.
• In ASIO driver mode, make sure your ASIO buffers are set at their lowest settings. A setting of 32, 64, 128, or 192 should be acceptable for most sound-cards as a rule of thumb.
• In WDM driver mode, make sure you slide the latency slider all the Way to the left. A millisecond setting of 5ms or less should be acceptable.
• Make sure you go to your interface/sound card manufactures web site and download/install the latest drivers for your operating system – and keep them updated regularly as they often change without notice.
• A/B test both driver modes to see what works best on your computer.
• Use Theatre Sound Cue Software that supports ASIO – like MixAction.

Zero Latency

Not all sound cards are made equal and the cheaper they are invariably the less equal they are.  Some recent audio interfaces claim to offer zero latency monitoring – your mileage may vary when using them.  Frequently they’ll offer, particularly when recording,  the capacity for both latent and non latent signals to be heard at the same time. Ditch this setting – along with the Sound Blaster “What You Here” to avoid a theatre sound technicians worst enemy – Director/Producer Temper Tantrums…

 To conclude – Sound card latency is addressable, but in many instances you are going to have to be prepared to test configurations to find what works with your unique machine, and if all else fails, upgrade to a professional, low latency, sound card.

Scott Kane

Warning – Tongue In Cheek.

The Second Part Of  A Quick Guide To Sound, Cues And Special Effects In Theatre History Follows.

GREEKS BEARING THESPIAN GIFTS

 If you were paying attention in Part 1 you would realize that those theatre sound engineers who managed to avoid being eaten by mega fauna helped make the difference between a flat performance and something more exciting in BC theatrical productions.

Sometime after the ice-age ended, bringing a whole new meaning to the word “freezing tracks” during a bounce down,  the world witnessed changes in the manner theatre was performed.

Categories of theatre grew up, which affected how actors worked and also gave rise to different forms of acting. 

[ Note well that this was somewhat prior to the “Method Acting School” which has led to some critics arguing we are now back at 50,000 Years BC. ] 

Enter stage left  – Ancient Greece.  Arguably the birthplace of what we might call today “modern theatre”.

In ancient Greece, plays were often staged to mark a religious occasion.  There were significant differences in the audience compared to today. Only prestigious men were allowed entry, with women frequently being refused admission.  Known as amphitheatres, theatres consisted of a  gigantic round stage encircled in two thirds by the audience.  Indicating that there was plenty of room for the ladies if they’d done something with the other third.

Greek Amphitheatres, we are told,  could accommodate an audience of 25,000.  You can probably guess how difficult it would have been to get a glimpse of what was going on from the back row. Ever the innovators the Greeks overcame this obstruction by ensuring the actors were loud with grandiose voices and immense gestures.

A very similar situation exists today in parliaments and government around the world…

For dramatic effect, given laser lights and mechanical scenery was a few years off, the Greek actors wore masks combined with costumes.

High pitched chorus – the sound cue engineers of their day -  were used to as a way of building dramatic events during the play and as a form of notice to actors, as teleprompters were considered beneath them.

The “Janus” mask, the symbol of modern theatre, has it’s origins firmly in Greek theatre.

Finally to improve the visibility of the production and to give an impression of reality the plays were held in daylight so that the real landscape formed the scenery for the play.

Warning – Tongue In Cheek.

 A Quick Guide To Sound, Cues And Special Effects In Theatre History Follows.

50,000 Years BC Sound Cue Candidates

While it’s probable there were highly creative, and by definition “theatrical” events staged, prior to recorded history it simply isn’t possible to define when the “first theatre production” took place.

It’s a fair bet though that it would have been a drama, comedy or a combination of both.

Looking at so called “modern stone age societies” would suggest drama as a very likely candidate, with perhaps some “romance”, as pictured left, to add spice…

Naturally the “actors” had similar concerns and passions to explore in their scripts as we have today, though their method of expression may have been a little more robust.

It is possible they may well have inadvertently coined the real origin of a famous thespian expression – by wishing each other well in a performance with a causal “break a head”;  which has evolved over time to the gentler and more socially accepted “break a leg”…  

These were the days when sound cue engineers made their sound effects by hand – or mouth.  There were no PA systems, in fact the loudest animal on Earth was not sound engineers but the mating call of the male Moose.  Paradoxically the deafest animal on Earth was the female Moose – but I’ll leave the details on that to David Attenborough.

Nope.  Sound Cue Engineers stood stage left, unhindered by messy lighting looms and follows spot stands. Faithfully recreating the sound of a newborn buffalo – while casting a nervous look over their shoulder for errant sabre tooth big cats.