TUTORIAL: AUDIO COMPRESSION - UNDERSTANDING FUNCTIONS - APPLICATION METHODS
WHAT POSSIBILITIES AND APPLICATIONS OF AUDIO COMPRESSION ARE THERE?
First of all, it should be mentioned that through a compression, as a rule, the Dynamic range of audio material reduces will. This means that the difference between the "quietest" and "loudest“Place in Audio material less will. A basic distinction is made between the application methods of the Up Compression and the Down Compression. First of all, it is important to understand this in principle. At the most famous is downward compression. Here certain passages with a high Level decreased, thus increases the signal density, what a Reduction in dynamics according to The process works similarly for upward compression, only here the passages are included low level raised to thus a Compression of the overall signal to achieve.
AUDIO COMPRESSOR TYPES
One differentiates primarily between Broadband and Multiband compressor. There is also the Tube compressor and Optocompressor. The Broadband compressor processed the complete frequency range of the audio material. At the Multiband compressor can be adjusted depending on the type various Frequency bands or define parameters that independent can be compressed from each other. The tube compressor works with a Electron tube instead of one Semiconductor circuitwhat many die According to opinion that has a Tube compressor ""warm“Sounds. Of the Optocompressor - in specialist circles one speaks of a "British compressor“- works with one light emitting diode in the signal control. Personally, I would rather describe the way of working as "lax " or "sluggish" define in the sound, which but still very musically sounds and one new possibility of creative work mixing or Testmaster opened.
BASICALLY THERE ARE THE FOLLOWING AUDIO COMPRESSORS:
- VCA compressor
- FET compressor
- Opto compressor
- Variable mu compressor
- Limiter (high ratio compressor)
WHAT OPTIONS DOES AN AUDIO COMPRESSOR HAVE?
- Attack: This value determines when the compressor should start working - if you want to keep the transients, you should choose a medium-short attack, e.g. 50ms
- Release: The release time determines how long the compressor needs to adjust the compression - this release parameter can also vary depending on the source material and signal. For example, you have a slightly shorter release time (e.g. 80-100ms) for drums that are played quickly, and a slightly longer or long release time (e.g. 140-250ms) for slow vocals.
- Ratio: This value determines how many decibels go into the audio compression and what is left of it. With a ratio of 4:1, 4 DB remains for every 1 DB that go into compression.
- Gain: This value can be used to amplify the compressed signal, which was previously reduced in level by the compression.
- Threshold: The threshold value tells the audio compressor at which level it should start audio compression.
WHEN IS WHICH TYPE OF COMPRESSOR RECOMMENDED?
"Good is what sounds good!"
So I wouldn't say one certain kind of compressor for one certain type of audio material is to be used. Especially in the area of Mixing and mastering the use of various compressors is important for the sound, but not necessary. Let's take a drum set from the skirt area, here you could with everybody x-remaining compressor or audio compressors work. I want that Overall signal sound more uniform from the gain, I would rather prefer a broadband compressor - for me this is it process like a kind of "Gluing process", In which I can identify the individual elements with the help of the"Glue“(Compressor) to one unity join. I use the multiband compressor for frequency images whose sub-ranges are different Parameters in Attack or release times have that Dynamics of the sub-areas varies greatly or because I only have one specific area of the frequency image would like to compress. in the test master I work with the Drawmer S3 multiband tube compressor.
APPLICATION EXAMPLE: VOCALS
In this example I show you the functions of a compressor and compression. Since the topic includes a very wide range of knowledge, it was unfortunately not possible for me to summarize everything about compression in one video. In the future there will be a subcategory for each main category, in which we will go into more detail about individual functions and application examples relating to compression and the audio compressor.
- In parallel compression, the main signal is partially compressed. The resulting effect is often called close and direct felt. Parallel compression makes sense wherever a compression or strengthening of the basic signal should take place, but the inherent character and dynamics of the basic signal should be preserved. This type of thickening is mostly used on drums or vocals, as the necessary "pressure" is missing. A possible setting for a parallel compression see z. B. as follows: Attack time: As low as possible (0,1 ms) Release time: As long as possible (200-500 ms) Treshhold: Set so that a gain reduction of 6 db is achieved. The compression method can still work for some Peak or RMS can be set. You can choose the setting according to your own taste. However, we recommend compressing according to peak. The parallel compressed signal can be adjusted according to taste. There is no fixed guideline for this.
STILL PROBLEMS WITH COMPRESSING?
With our analog compressors from Drawmer, Neve, SPL, SSL and Elysia, we are happy to provide a dynamic and powerful sound for your song!