If you've ever mixed a track, then you should know what compression is. What you might not know is that there's a special kind of compression specifically designed to help you enhance the quieter parts of your song, making them stand out amidst the plethora of sounds in your mix: upward compression.

Imagine what this type of compression can do to your mix. By using it, you can add depth and texture to your mix and amplify those quieter parts that make your tune unique. Often overshadowed by the largely more popular downward compression, upward compression is a crucial tool in the arsenal of music producers of all levels and genres.

Today, we'll take a look at this formidable post-production tool, understand what it is, and how you can use it to take your tracks to the next level.

A Few Words on Compression

Compression is a crucial technique in post-production and is used to make audio sound better by reducing the difference between the quietest and loudest parts of a sound. Usually, this is done by making the loud parts quieter while keeping the quiet parts the same.

Compression makes the sound more consistent and easier to hear, especially when there are many sounds playing at once. Compression can also help balance the different sounds in a mix and make them sound more pleasing.

There are different types of compression, like downward, upward, multiband, and parallel compression. Each in their own way, these types of compression can make audio sound better, and make a track sound like a professionally-recorded hit.

Upward Compression: A Definition

In short, upward compression increases the volume of quieter sounds in a mix without affecting the louder ones. It does so by boosting the volume of sounds below a certain threshold, making softer sounds more prominent.

This post-production technique is great when you have quieter passages or tracks that need to be louder without compromising the overall dynamic range of your song. Upward compression can be applied to individual tracks or the entire mix.

When done right, upward compression can enhance the clarity and depth of your tune, emphasize low-level details, and add warmth and presence to it. It's used across all music styles but is particularly useful when working on tracks that have soft yet important moments, like acoustic genres. Regardless of the music field you work in, upward compression can truly revolutionize your sound for the better.

How Upward Compression Works in Music Production

It should be clear by now that you should use upwards compression when you want to emphasize and enhance quieter parts in your mix. Now, let's see how you can translate this knowledge into practical improvements to your song.

My recommendations should work regardless of your style and DAW; however, bear in mind that it all comes down to the genre you work on, your personal taste, and your workflow. Finally, pro users might be interested in multiband upwards compression, which adds a whole new level of frequency adjustments.

1. Choose which low-volume elements you want to enhance. These are usually crucial parts for the texture or emotional impact of the piece: soft vocal parts, wind instruments, a subtle piano melody, and so on.

2. Set the threshold level below which the upward compression will kick in. Sounds below this threshold will be amplified, while the rest will stay untouched.

3. Adjust the ratio and makeup gain reduction to make sure the boosted signals blend well with the rest of the mix.

4. Check the attack and release times so that the compression sounds natural.

5. Give the final touches to give your track a natural feel, making sure the soundstage feels cohesive and coherent.

Examples of When to Use Upward Compression

There are endless reasons why you might want to boost the volume of quieter parts of your track, but in my experience, here are some of the most common ways in which an upwards compressor can be used:

Vocal Tracks: To make sure that the quieter nuances of a vocal performance are as clear as the louder ones, including whispers, soft words, or breathy elements.

Acoustic Instruments: That's where upward compression can completely change your track, bringing out the quieter subtleties of guitars, violins, and pianos and enhancing the texture of the recording.

Ambient and Field Recordings: Highlight quiet details in ambient soundscapes or field recordings, making them more immersive and detailed.

Drums and Percussion: If you want to highlight the natural resonance and decay of drums and cymbals, upward compression is your best bet.

Background Vocals and Harmonies: To ensure all elements are clear without competing with the main vocals, adding depth to the mix.

Classical and Jazz Recordings: To ensure that the quieter passages are audible without compromising the overall dynamics, preserving the intention behind the softest notes.

Restoration: To make important audio elements more prominent when working with old recordings or tapes that usually have a lot of background noise or variable levels.

Upward vs Downward Compression

Upward and downward compression are two sides of the same coin, but downward compression is the one you use 80% of the time.

A downward compressor reduces the volume of audio signals above a certain threshold, so you can use it to mitigate peaks and add punch and density to a sound.

An upward compressor, as we already saw, increases the volume of audio signals that fall below a set threshold, making quiet passages more audible and improving the clarity of quiet audio.

Both these techniques adjust the dynamic range but in opposite directions: downward compression narrows the dynamic range by reducing loud sounds, while upward compression expands the perceived dynamic range by making quiet sounds louder.

Upward vs. Parallel Compression

Upwards compression and parallel compression share some similarities, and to some extent, you can use either to amplify quieter sections of your tune. However, they achieve this result in ways that affect your mix differently, so it's useful to know which one best suit your needs.

Parallel compression is a process that blends an unprocessed signal with a heavily compressed version of that same signal. Hugely popular across genres, but especially in electronic and other galvanizing genres like rock or metal, this technique adds energy and presence to the signal while maintaining the original dynamic range.

If you mix together a compressed and uncompressed version of the same audio signal, the result is that you're effectively enhancing the lower levels, as the downward compression in the compressed file is already affecting the signal, which is not unlike what you'd get by applying upward compression.

However, these two compression types are very different when it comes to the impact they have on dynamics. Parallel compression adds a certain punch and energy that you won't get with upward compression, which tends towards a more natural, cohesive effect.

As it's often the case, there's no one-size-fits-all when mixing tracks, so all you have to do is try both and see which one enhances the beauty of your track best: the subtlety of upward compression or the more energizing effect of parallel compression.

What about Upward Expanders?

Since we entered the upward compression rabbit hole, we might just as well discuss another interesting topic: signal expansion. Unlike compression, which reduces the dynamic range, signal expansion aims to increase it, making the soundstage more immersive.

There are two main forms of expansion: downward expansion and upward expansion.

A downward expander reduces the volume of audio content below a certain threshold, which is ideal for noise floor reduction. It's often used to decrease the level of background noise or to increase the dynamic contrast in a recording. If you want to make a recording sound clearer and more focused, downward expansion is a great option.

On the other hand, an upward expander can increase the volume of signals that exceed a set threshold, which can make a mix sound more dynamic by enhancing the louder parts and increasing the overall dynamic range.

Final Thoughts

When used right, downward, and upward compression can make your song sound professional and clear, as if mixed by a professional recording studio. As the loudness war in the music industry seems to emphasize the importance of punch and energy, being able to enhance the beauty of quieter sounds is certainly a way to prove your skills as a music producer and artist.

Remember to try out different settings and techniques to find what works best for your genre. With practice and patience, chances are you'll master upward compression and create mixes that stand out from the crowd.

Have fun!