Friday 3 February 2012

Digital Audio (formats)

In this section I will be focusing on Digital Audio and what happens when an analogue signal is converted to a digital format, the factors that should be considered when choosing the correct format for your particular needs.
I will also look at how digital formats differ, and try and give you an idea of how there differences are going to effect your audio...

the subjects I will be starting on are:
Popular Digital Formats:
A quick look at the most popular formats, their typical usage.
  • Lossless (wav)
  • compressed (MP3, OGG, WMA etc)
DA/AD Processes
  • overview & notes on fileaize.
  • Bitrate & Frequencey
  • Encoding stage (with regards to hardware)
Format Comparrison
 MP3 vs WMA (compressed vs. compressed).
WAVvs MP3  (lossless vs compressed)


*check back soon for this part - I'm still in the middle of writting it*

Wednesday 1 February 2012

Sound Design for Video Games

I was originally going to call the section 'recording vocals for video games, however I realised most of the main points of interest also ralate to other sources of audio ...so...

At first glance sound design for games might not seem any different from that of film, music production or even for TV/radio however vdeo games place a set of unique contraints on the sound designer that can either hinder or help the creative process.

  • First thing to consider if the playback medium and its capabilities, namely what bitrate/frequency formats can the system (or console) handle?
  • Secondly is there a limit on the number of simultanious sounds that can be played back (polyphony range).
  • How is the sound output? Is it a device that uses headpones or proprietory speakers? Is the device likely to be plugged in to a larger amplified system such as home surround sound playback system? ...and how will all of these factors affect the gaming back experience?

To use an extreme example;

Imagine creating a score for LOTR for the Playstation 3 (or PC), now Imagine trying to transfer that gameplay experience to a gameboy (original) with all its polyphonic and format related limitations.

Each consol (or playback medium) will offer up its own set of contraints with regards to what audio formats are acceptable and this should be taken in to account as early on as possible to avoid wasted time/effort. ..For example it may not be worth while recording a vocal (eg shout) using an ultra-precise microphone at high resoltion if the format used to play back is limited to 22.05Hz . Each situation should be assesed to see what is possible and what is not, especialy where console gaming is concerned (or portable devices). ...memory allocation may also be limited!

Tuesday 31 January 2012

Abstract Theory

The Abstract Theories
This section doesn't really come under guide/tutorial, its more of a collection of ideas, or food for thought relating to music and how it effects the people that hear it, either intentionally or unintentionally.

A selection of phenomena and pequliar side effects of sounds, alot of it has to to with psychology, some of it is a mater for philosophers and the rest is a result of evelution and the way the human body interperated the audable feedback we get during the course pf our lives.
*time for me to sleep - I will continue this when I wake*

Wednesday 18 January 2012

Compression (a complete guide to)

What Is A Compressor?
A compressor just is a device used to regulate the dynamics (volume) of a source signal (audio).
It works by effectivly stopping the signal exceeding a value (maximum volume) determined by the operator (you).
If you were to classify compressors in regards to effects units, it would belong to the dynamic processor family as opposed to time-based effects processor (such as reveb, delay, flangers).

Setting Up Your Compressor:
Before you start ensure you have connnected your compressor/limiter to mixer via the inserts.
- Begin by adjusting the compressor's threshold until the peaks start triggering compression.
- Now adjust the Ratio as desired (depending on what your recording) ...we have now found our starting points, now you want to adjust (fine tune) ratio & threshold together until you have the sound your after.
- Time to move on to the attack and release... The attack will change how long it takes before the compressor kicks in (each time it is triggered by exceeding the threshold), and release controls shape how the compressor 'feels' after it has kicked in (the release will determin now long the compression effect will last before the cycle ends).
- Finaly adjust the output gain to compensate for any difference in volume that has occured due to the compression effect.
- Make use of your bypass buton (if you have one) to check the original level, your looking to have created a new average volume, so now you want to bring it up/down to aproximatly the same level you started with.


Things Worth Knowing:
The following are just a few suggestions (starting points even) to put you in the right direction, ofcourse what music/sounds you record will effect how the compressor reacts and thus how the final sound will be so keep that in mind. Also dont forget to keep an eye on your output gain control (if you have one) when dealing with harsh compression.
- Compressors can be set up to act as limiters, the only difference between the two devices being that the limiter will have faster responses (shorter attacks = more effective limiting), if you want to set your compressor as a limiter make sure your settings are as follows: Inputgain=zero, threshold=zero(or or -1db ), ratio=10-15:1(or as high as it goes), attack=short,release=short-to-mid, output gain=zero.
- Suggested ratios: bass guitars around at 4:1, soft vocals around 2:1, heavy vocals around 4:1, acoustic guitar 2:1, electric guitararound 5: 1, percussion (shakers etc) around 2:1., synth lead (with reverb) around 5:1.
- Fast attack would be more prefferable for anything that has sudden peakse,
- Slower attack is good for sound sources that require a a little punch before the compressor begins flattening flatening the sound (such as kicks when you want a little ckick at the begining or more impact), I also find a really slow attack nice on bassline or synth pads when reverb unit is used via inserts (not send/return).


Common Compressor Types:
- FET, Compressors attempt to emulate valve compression characteristics but more reliably than valves can. FET compressors are apparently nice on drums. (but i havent checked).
- Optical (opto), as the name suggests they implement light sensitive circurtry. They have slower response times than alternatives - this can be for the better or worse depending what you are recording. If your looking for a dedicated compressor for vocals or anything that needs slow attacks you may find an Opto compressor;'s characteristic 'sound' better for your needs.
- Valve, Every one is familiar with the term valve compressor even if they dont know exactly what a valve is.. but you dont need to know how it works all you need to know is they are tempremental (the longer its on the more pronounced the effect), pronce to breaking if transported alot and generally more expensive... But for some reason they just seem to sound a little warmer, this is most likely due to their higher noise levels. (FET compressors can have higher S/N ratio)
- VCA, Voltage Controlled Amplifier compression is very precice and its another one of those does what it says names that well... does what it says ^_^.
Its internal circutry has less noise/colour and responses are very high making them very precice and therefor flexable devices all round.

Additional controls etc:
The following functions/controls are not nessesary in a compressor but worth while knowing about, if you have them.
Bypass - Bypass often gets forgotten completely and results in a lot of scratching of heads when at a later point and asking questions like 'why is that track so quiet when it was so loud an hour ago' or 'why is this acoustic guitar distorted? ..I thought I had lilited it. The bypass function lets you compare what it sounded like before and what it sounds like now (post effect), if you didnt have bypass function you would be constantly plugging then unplugging they compressor or repeatedly reserting the controls.
Bypass also means you can permanantly connect your compressor to your mixer if used alot and not have to worry about damaging the socets through wear.

Side-Chain - Side-chaining is a technique that is widely used in music production, especialy electronic music. Sidechaining is basically getting one source to control another. so it could be compressor#1 tells compressor#2 when to trigger, or it could be oldskool synthesizer#a tells compressor#b when to trigger.

Warmth etc - these are not really anything to do with the actual compressor just additional things to add a little character to the sound... it could be a valve emulating transistor circut, or a subharmonic exiter effect process, it really depends on what you own.

Gate - If your lucky your compressor will have a built in gate, which will help clean up your recording (at least the dead air). ^_^ ...The gate will completely halt any sounds that do not exceed its threshold from passing (being heard), if it has varible controls (attack release) they work in the same way as the compressors attack and release do but they are unlinked (work independently of each other).

Tuesday 17 January 2012

Patchbays

Midi & Audio patchbays are generally only found in studios where either there are issues with space or time. Using a patchbay allows for quick re-routing of signals in situations where you have more equipment than there are available channels to plug them in to... or if you have a selection of effects units some of which that are not used frequently.
Some midi patchbays also allow for midi thu - allowing you to effectivly split the midi output from one device to multiple devices (this can be handy for things like layering drums using multiple sources).

Connecting to your patchbay:
Midi patchbays predictably relly on standard midi socketing (5pin DIN).
Audio patchbays come in a couple of variations... the most common (and cheapest) patchbays use 1 1/4"TRS jack (with regards to front side patching) but some may use old style Bantam jack (bantam jacks are the old manual telephone system patching architecture, which use small brass jacks that look similar to mini-headphone jacks).
With regards to the rear side patching of the audio patchbay, it may be designed to accept microphone cables, TRS cables or bantam cables - although bantam cables require manual soldering/adapting as the as the technology its self is no longer produced).

Oscillators (an introduction to)

The Oscillator (VCO) is the part of the synthesizer that generates the initial tones that are shaped (envelope) to form sounds as desired.. the number of oscillators, the type of wave they are generating, combined with the way in which the tones are combined determines the type of sound that is produced.

It is the most important module in the synthesizer as the final sound produced is primarily determined by the way you set up your oscillators. The common controls found on your oscillator are:
Wave Type -Simple waveforms (wave/sine/saw/tri/square), complex waveforms (pulse, noise etc).
Octave Select - Primarily used to fatten up sounds.
Semitone Select - Useful for creating small chords, especially on monophonic synthesizers.
Detune Pitch - Useful for creating more realistic sounds.

Hardware Sequencer(s)

A guide to the basic features of a hardware sequencer.


Recording Modes: ('Grid', 'Step', 'Overdub' or 'Replace').
Grid mode is your standard mode for recording rigid beats etc, each note recorded on a keyrange basis (as in select the not the sound is on, then select when the note is triggered).
Step mode is the traditional method of entering notes, by selecting the order the notes are played , manualy keying them in via built-in or external midi keyboard.
Overdub mode records over any previous midi data.
Replace mode overwrites your patern as it plays through the sequence.


Quantizing + Note Editing.
Essential for getting your grooves or riffs just right or correcting mistakes.
Song/Pattern Sequencing
Songs are built up by chaining together individual phrases/patterns in to a larger sequence.
Mixer
Volume of each track, panning position, automations and effects.
The mixer may also allow routing/grouping of midi/audio to specific midi/audio outputs allowing for greater control of the final mix (eg route all drum tracks to midi out1 and melody to midi out2).
Effects
Not all sequencers will come with built-in effects but if it does it is likelt to include compression, reverb, delay, and chorus/flange.
Some sequencers may also be able to introduce things like midi delay in to the midi data.

*all of the above are expanded upon in my other posts*