What does frequency do on a compressor?

What Does Frequency Do on a Compressor?

Compressors do not affect all frequencies in the same way; higher frequencies tend to be less affected by the same settings than lower frequencies. Indeed, this difference lies in how compressors react to different frequencies, leading to practical implications in audio engineering. Bass frequencies carry more energy and thus often trigger more compression, a concept explained in detail by the basics of compression.

Compression and Frequency Response

Compression doesn’t affect varying frequencies uniformly. Lower frequencies possess higher energy for similar perceived loudness; thus, they trigger greater compression. This situations lead many compressors to feature filters within their side-chain or detector circuits, adjusting their reaction to lower frequencies.

Examples of Compressor Settings for Low Frequencies

Hardware like the Drawmer 1968 compressor has a “BIG” switch, which filters low-end frequencies from the detector circuit. Models such as the API 2500, along with its plugin emulation from Waves, offer a “thrust detector” switch with settings like "loud," "medium," and "normal". These settings determine the amount of low-end roll-off in the detector circuit.

Influence of Analog Components

Besides the detector circuit configurations, analog components like tubes and transformers can significantly affect frequency response. Classic compressors are favored because they impart a unique sound to the audio passing through them, adding subtle saturation and altering the EQ balance, especially by driving harder settings.

Multiband Compression and Side-Chain Techniques

Multiband Compressors

Multiband compressors provide another way to affect frequencies differently by splitting audio into several frequency ranges. Each range can be compressed independently, offering precise control.

Side-Chain Input Usage

Using the side-chain input, compressors can react to specific frequency ranges. For example, a de-esser works by filtering a sibilant vocal track to emphasize troublesome frequencies, feeding this filtered signal into the side-chain while the full audio passes through the regular input. This method allows compressors to reduce gain exclusively during sibilant frequencies.

Single Band vs. Multiband De-Esser

Single band de-essers might reduce gain for all frequencies, while dedicated and plugin-based multiband de-essers provide internal filter circuits, offering more control. A multiband de-esser is advantageous for complex sources like drum kits, tailoring the brightness control of cymbal crashes without affecting other drum elements.

Data Compression and Audio Quality

Three Important Considerations Before You Buy a ...

Regarding low-bitrate audio compression, such as MP3 or MP4/AAC, these formats use lossy compression. They aim to minimize file sizes for easier streaming and faster downloads by discarding less noticeable audio parts. However, heavy compression results in more audible artifacts, as explained by a new plugin that compares various codecs in real-time.

Choosing the Right Encoder

Different encoders perform better on various music types. Testing and comparing them using specific audio content ensures choosing the best option for the desired sound quality. On the other hand, FLAC, a lossless compression format, reduces file sizes without compromising audio quality, making it a preferred choice where high fidelity is essential.

Need more detailed guidance? Visit hydraulic compressor working principle for in-depth information on choosing the right compressor.