Live Production Systems Learning Journal
Entry 1
Audio Mixing is blending and moulding the sound so that the no individual element stands out. As described by Doug Fenske, an audio mixer “is a device with the primary function to accept, combine, process and monitor audio” before it is heard across the front of house (FOH) system and through stage monitors.
Within the venue, which would be around the size of the sonic lab (L 17m x W 11m x H 7m), you would most likely have an ensemble of no more than 5 performers due to the fact that it’s a relatively small space and the staging would require as much room as possible. You would be more akin to seeing a sound reinforced performance in the venue due to its sound reinforcement capabilities. Considering the location of the console’s mix position is just as important as speaker placement As discussed in Live Audio (Swallow, 2010), the centre of the room is the sweet spot as it is where “all points of the audio come together and are audibly in focus.” Having the console marginally off-centre can ensure that any identical frequencies can be mixed properly without them summing.
When reproducing live sound, mic line level is too low to be able to be processed through the console and therefore has to be turned into a line signal level when it reaches there. It’s not only microphone signals that are mixed before coming out of the FOH system. If there are acoustic instruments needing connecting to the FOH system, you would be using a DI box to allow longer cable runs and “polarity switching to correct phase problems.” You also require inputs from instrument microphones in order to amplify instruments that have no direct outputs such as drum kits and signals such as guitar line signals to the console. Due to this, you would need to use a mixing console with around 20 input channels in order to mix the FOH sound fully and ensure there’s enough space to input everything.
Analogue mixing consoles that have between 16 and 24 outputs include the Mackie ProFX 16v2, that has 16 inputs and built in effects processing, the Soundcraft Signature 16 analogue mixer, and the Mackie Behringer SX2442FX, which has 16 XLR mic inputs and a 3-band EQ.
Viewing a console in person would help in deciding which console to buy. Choosing the one that suits your needs is essential, and by getting a feel for how the mixer works, its layout and what the mixer includes. Things to consider when buying a console are whether the console has phantom power, direct outputs and what type of EQ settings the console has, such as a 3-band, 5-band or 7-band EQ.
Entry 2 (
Venues may have pre-installed consoles which means adjusting to what you’re using. This could also mean that if you’re used to one console or another, you’ll have to relearn how to use it. This happens when transferring between analogue and digital consoles, as they both have totally different functionalities. With the event being performed in a space similar in size to the sonic lab, it would be a relatively intimate performance.The outputs required would be direct outputs for instruments such as drum kits that need minimal sound reinforcement. One would also require mix buses in order to apply effects such as reverb onto signals such as vocals, and specific outputs to the monitors in order to enable the musicians to have monitor mixes. Due to the number of input signals, you would need a minimum of 8 output channels and maybe a couple of direct output channels.
Digital mixing consoles have advantages and disadvantages over analogue consoles. A digital console would give you a higher quality of sound but the analogue can round things off to make the sound seem more natural. Another advantage is that due to being able to save settings, there’s “instant “recall””. This makes life easier for sound engineers, as digital console manufacturers make smaller consoles but having overlapping pages to utilise more features and so that you won’t have to manually readjust each part individually. Digital mixing consoles use digital connections, namely AES and S/PDIF, which keep noise and phase shift out of the signal path and avoid analogue/digital converters. AES is a balanced connection that keeps it in its digital format until the last second. S/PDIF functions in the same way, though the connection is unbalanced. This would certainly inform my decision of which mixer to choose.
Presonus STUDIOLIVE 16
https://www.gear4music.com/Recording-and-Computers/Presonus-StudioLive-16-Series-III-Digital-Mixer/1TZL?origin=product-ads&utm_campaign=PLA+Shop+-+Presonus&utm_medium=vertical_search&network=google&adgroup=Presonus.+All+Products&merchant_id=1279443&product_id=85521d1&product_country=GB&product_partition_id=92329185199&gclid=Cj0KCQiA_s7fBRDrARIsAGEvF8SQYno5AMyiaxZ5Jqv11pqeOH8toGjEPrEcO5DQ5s_nRs5AefJdapkaAkO-EALw_wcB
A few examples of mixing consoles that could be considered for performances of this kind include the following. Firstly, there’s the Behringer X32 which is a digital mixer that has 32 input channels – 2 layers of 16 input channels but can support up to 48 channel snakes, 24 mix buses. This mixer would suit a venue of this size due to its advanced capabilities and price, which is very reasonable. Secondly, you can also get the PreSonus StudioLive 16, which has 24 input channels, 10 outputs and has a vast array of signal processing.
Entry 3
As discussed in Sound and Recording (2014), a microphone is “a transducer that converts acoustical sound energy to electrical energy” by using a diaphragm system to pick up the signal. There are different types of diaphragms used in different microphones which then gives them different purposes. The moving-coil or dynamic microphone is mostly used in live work for handheld vocal use, due to its robust build and the use of a mesh shield that attenuates any background noise and heavy pronunciation. The capacitor, or condenser, microphone would also be used in a live context to reproduce sounds coming from instruments such as drums, or guitar amps. This is down to the fact the microphone is lighter and with its resonant output of around 12- 20kHz, the increased output isn’t as obvious.
There’s added advantages to using a capacitor microphone as there’s an amplifier built in to the microphone and therefore can be changed to a line level signal. Due to its cardioid polar pattern, there’s a more focused directionality and any unwanted sound is kept out of the mic and it “minimises the risk of feedback, from PAs and amps”. There are other variants of the cardioid polar pattern – the hyper- and super-cardioid – that could be used in a live context, though the may have sound coming from the rear of the condenser microphone due to the rear of the diaphragm being open but with obstacles. One wouldn’t tend to find omni-directional or figure-8 microphones in live work due to the polar patterns not being as focused. That said, one might find a switchable microphone in a live context due to its ability to switch between polar patterns as it may be of use for vocal reproduction so it might be a bit more useful than have 2 separate polar patterned microphones.
For the event needing live sound reinforcement in the venue, I would suspect to need around 10 microphones to enable everything to be reproduced properly and accurately. There would most likely be multiple vocalists that would need mics. There’s always the possibility that a drum kit could be used so the bass drum, snare and overhead microphones would be needed and if there were any guitar amps being used the could also be helped with a microphone so they are reinforced and the sound is mixed well.
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Entry 4
To understand different microphones, discussing the differences between the polar patterns helps. There are 3 main polar patterns – the omnidirectional, the figure-8 and the cardioid. Omnidirectional polar pattern’s microphone’s diaphragm is only open at the front and responds to absolute changes in air pressure. Figure-8 polar pattern is
10 different due to the diaphragm being open at both the front and back, which causes the diaphragm to respond to pressure difference. A cardioid polar pattern however, is a polar pattern that is a combination of both the omni- and the
11 fig-8, where both the front and back are open, but the rear has obstacles to block or colour the sound. The frequency response is less smooth than the other two but this microphone has a more focused field that sound would be picked up from, hence its valued use in live work.
Another element to consider when using microphones is what is called the proximity effect, which happens when using a cardioid microphone. The closeness of the sound source to the microphone can cause bass tip-up, where “the bass response increases more and more”. This is one con of a cardioid microphone but they do rule supreme within the live sound world. When discussing or purchasing microphones, be it for studio work or live work, the pros and cons of each type are.
When it comes to dynamic microphones, they are cheap, robust and have "in-built compression of signal high sound pressure levels (SPLs)”. On the other hand, the cons really do outweigh the pros in terms of live sound work. Their resonant peak is around 5kHz which is no good for higher frequencies and the fall in response occurs very rapidly above around 10kHz, there’s more of a slower response to signal and they are heavier which restricts the diaphragm movement.
Having said this, condenser microphones aren’t exactly perfect either. Even though they’re more accurate, are smaller and lighter and have a better high frequency response, they’re more expensive, a lot more delicate and do not work well in damper conditions. To enable good and informed purchases to be made, one would be more inclined to research the different products available from different companies. It would also be helpful in making notes about the different capabilities the microphones you are considering buying have as this may sway you regarding which microphones. One would look for elements such as frequency response, sensitivity and dynamic range and would depend on what the available budget is.
Entry 5
Regardless how high the quality of the equipment you buy or have for a performance venue, its all
15 fairly useless without ways of connecting it all to each other. There are multiple cables with a variety of terminations required to perform successful live sound reinforcement.
There are two types of XLR cables used. The first is a XLR-3 cable would be used to carry an audio signal at greater lengths from microphones across the stage to the mixer and also be used for carrying signal from the mixer to the monitor so that the performers have audio mixes of each other. These connections have 3 pins – one is a
15 screen cable; the second is a signal send and the third is a signal return. You would require more of these cables than any other for amplification purposes. The second is the XLR-5 which is a 5 pin termination used for DMX control of lighting. These have one screen and two sets of sends and returns (1 is screen, 2-5 are sends and returns).
Unbalanced (A gauge) jacks would tend to be used for guitar and bass amplification with
15 amplifiers. The cables would be shorter as the unbalanced connection restricts some interference, but if line is used to “carry an audio signal over tens of meters, the cumulative effect of interference may be unacceptable”.
The last termination is the Speakon which would be used to carry loudspeaker levels for the FOH sound, and there may be a minimum of 2 speakers so you wouldn’t need too many and these would be long enough to reach the wall but not too long.
There are other interconnections that may be required for the performance. One option would be short insertion cables to be able to use external processors so that there’s a strong signal flow. A second option would be DI boxes, that convert all line signals into balanced mic line signals.
Entry 6
In a performance venue of this size, it could be used for multiple events and therefore may have moving equipment to accommodate this. This will then result in the front of house loudspeaker array being a moveable installation. In venues that are larger, or are permanently used for reinforced performances, the array will more than likely be fixed.
There are two types of loudspeaker arrays used in live work, active and passive. There are advantages and disadvantages of having both systems. When using a passive system, it’s cheaper and there’s only one amplifier required where passives need two amplifiers which then makes the system expensive. That said, the loudspeaker filters are less accurate and the drivers are harder to match with sensitivities, whereas the filters in active ones are more accurate and each driver’s power output can be controlled.
Due to the venue being relatively small (around 150 seats) and the music being performed will be of a pop nature, the level of sound power output won’t be a lot. The level of sound power output suggested by crown audio for “Pop or jazz music in a medium-size auditorium… [is] 250 to 750W” which makes sense as there’s a general rule of thumb for this as 5W per seat. Some examples of loudspeaker combinations available commercially with this sound power output include the SubZero 700W 12” Active/Passive PA System; the Genelec Studio Monitor which has a 400W woofer, 120W Midrange and a 120W tweeter; and the Yamaha CBR10 Passive PA speaker. Choosing a loudspeaker array would include what your budget is, the loudspeaker performance; driver design – cone or dome; how many drivers and the crossover filters used in the loudspeaker and the loudspeaker sensitivity, which is how efficiently the loudspeaker the conversion from electrical sound energy to acoustical sound energy happens.
Entry 7 (Week 8 – lighting design)
Some suggestions for reflection:
What are the advantages of LED lights over incandescent stage lighting?
Efficient, cost effective, no loss in brightness, bulbs won’t need changing, come in variety of different lights
There are a number of categories of light used in stage contexts. What sorts of applications are appropriate for each category of lighting fixture?
Floods – house
Followspots – movement
PARCAN – strong colours, SFX – stage lighting, strobes etc
Profiles – lighting up people, i.e. moving heads
What categories and quantities of lights might be required for your venue?
As above – floods can be used for house
Parcans for walls, floor, stage
Moving heads/profiles – splashes of colour, lighting up performers
What control functionality would you require from a lighting console in order to use your specified lights?
Dimming, movement changing, colour changing, intensity, seletion of individual lights
What lighting consoles are commercially available with this sort of control functionality?
Titan Mobile – Avolites
2 more
Entry 8 (Week 9 – loudspeaker array)
Talk about:
Horizontal dispersion
Vertical dispersion
Different types of arrays
Functions
Advantages
Usefulness