Audio summing, sometimes called analog summing or summing, is an audio engineering technique you might come across if you're lucky enough to step outside your bedroom studio. Creating a polished track isn't just about creativity, it's also about strategy.

As we'll discuss below, summing in audio is a technique where audio signals are processed through analog hardware to create distinct textures in the final mix. In this guide, we'll uncover what audio summing is and weigh the pros and cons of whether or not it's the right choice for your mix.

What is Summing in Audio?

Audio summing is the process of bringing together several tracks into a single stereo mix or master track. The term "summing" specifically tends to imply that the electrical signal is processed through some analog equipment, which is why summing is often referred to as analog summing.

An analog mixer sums signal in a way that digital summing (or just bouncing out your master fader in your DAW) does not. By nature, hardware circuitry introduces subtle "imperfections", sometimes referred to as nonlinearities, which can provide warmth and character to a track.

In order to participate in true analog summing, you need to have access to equipment like an analog summing box, which brings together your multitracks into a single mix. Analog summing boxes have components like capacitors, tubes, resistors, and transformers, all of which contribute to their fingerprint character.

What's the Difference Between Analog Summing and a Digital Bounce?

It's worth noting that there are several specialized plugins designed to recreate some of the warmth and artifacts produced by an analog console. For instance, the Waves NLS Nonlinear Summer plugin is meant to be used this way in the digital summing process.

Analog summing doesn't come without its drawbacks, either. It's important to understand that analog equipment can be fairly unpredictable, and too much analog noise or crosstalk can certainly compromise a mix. Some engineers might prefer digital summing for its precision and predictable nature.

It's also worth noting that analog summing has a fairly high barrier to entry: hardware consoles and an actual analog summing box can be pretty expensive, starting at a thousand or more dollars on the low end. You might not have access to analog summing equipment in a home studio setup, and that's okay!

Depending on how summing is conducted, it can be a somewhat minimal difference in the overall impact of a song. It's the cherry on top if you have the luxury of analog summing a master fader, but it's not a make-or-break component of the music production process.

How to Sum on Analog Consoles

Summing on analog consoles is a simple, but nuanced process. Since the output of your sound is highly dependent on your equipment choices, one engineer's analog summing is likely to sound completely different than another's. The audio summing itself is simply a matter of patching, gain staging, and setting up your analog chain for your audio tracks to pass through.

What's a Summing Mixer or Summing Bus?

A summing mixer or summing bus is a hardware piece that allows you to send individual tracks from your DAW, process them through analog summing, and send the processed electrical signal back to your DAW for final processing. Many producers and engineers utilize this approach since you get the option of including the hard-to-replicate analog character without sacrificing the flexibility that comes from processing audio digitally.

Digital Summing versus Analog Summing Compared

Both digital and analog summing methods can combine multiple multitracks into a single source, but they both go about processing audio differently. Not sure if you should process via analog summing or digital summing? Here are the two methods compared for reference:

Analog Summing

As the name suggests, analog summing relies on physical gear to combine signals and create the unique character of the final mix. In practice, the warmth produced from analog summing is subtle distortions and harmonics that are created by the capacitors and transistors built into the hardware pieces. Analog summing is an older method of audio processing, but it is still incorporated into the recording process today due to its unique properties.

PROS:

• Known for creating warm, rich soundscapes through analog processing.
• Some listeners say that analog summed music has a more present stereo field or separation between the different tracks.

CONS:

• Requires basic knowledge of circuitry and understanding the ins and outs of your particular analog summing box or summing chain.
• Can be incredibly expensive. An analog summing box can cost over a thousand dollars on the low end.

Digital Summing

Digital summing uses mathematical, digital signal processes to sum audio with your digital audio workstation software like Pro Tools or Ableton Live. It's clean, precise, and provides fairly efficient feedback. Some engineers may incorporate analog emulation plugins into their digital summing workflow in an attempt to capture some of the character that may be lost from a purely digital sum.

PROS:

• Digital summing just requires a DAW, you don't have to shell out thousands of dollars for analog equipment.
• Digital summing tends to produce a cleaner, precise sound which may be more suitable depending on the genre of music.
• Doesn't require additional learning and understanding of hardware analog processing.

CONS:

• Digital summing is very clean, which can be helpful but it might hurt the character of recordings that rely on warmth, especially those within the indie or rock space.
• Some feel that analog summing produces a more present stereo mix, creating a unique stereo image through circuitry.

What is Hybrid Audio Summing?

If you have access to analog gear but want the precision that comes with digital tools, you might want to consider hybrid audio summing. In this method, you get the best of both worlds by creating tracks digitally, processing them through a compatible analog summing box, which will then send the processed mix back to your digital audio workstation. This method can be achieved using a hybrid mixing console or a DAW to analog summing box such as the Dangerous Music D-BOX+.

Does Analog Summing Make a Big Difference?

Depending on who you ask, analog summing makes all of the difference or not much of a noticeable difference at all. The reality is that recording, production, and composing are all much more integral to the quality of your song.

Analog summing is a great mixing and mastering technique to experiment with, but not having access to summing tools shouldn't deter you from making tracks if you don't have access to this technology.

I recommend checking out A/B tests on YouTube like this one to gauge whether it is worth additional investment:

Audio summing is what you make it. It can be a very helpful tool that adds character and depth to your mixes. However, it's important to put into perspective that analog summing is nice to have, but not wholly vital to producing an amazing track.

You can certainly craft a fantastic recording without the aid of analog gear throughout the mixing, recording, and production process. Just know that summing is there as a valued technique should you have access to analog gear.