🧪Lab Report #2 : Sends vs Inserts in 2025 — Why the Old Rules Still Matter
Do we still need to use sends for reverbs?
What's up, Lab Dummies?
The other day, I was watching Jason Joshua demonstrate his front-to-back panning technique, and I thought it was something I really wanted to discuss. One thing I always try to do is create a very clear and three-dimensional mix, and reverb is often underutilized when it comes to creating space and depth.
Now, of course, this is something we can use with early reflections, and there are a few different techniques that we can talk about at a later date. However, one thing I did want to mention was that the way he was using the reverb was essentially on the track itself.
TLDW : He was using the reverb as an insert on the vocal to move the vocal “back and forth” in the space by adjusting the wet/dry knob on TrueVerb. I know many people have thought this:
"Why do people recommend sending reverbs to sends? Why don't we just use them on individual elements?"
In fact, you might be someone who's doing exactly that. So today, I want to talk about that. Let's get into it.
Sends vs. Inserts: The Great Reverb Debate
In the world of audio engineering, technology is constantly changing, but some techniques that started back in the day are still valid for a solid reason. A lot of beginners will slap reverbs on everything, and this is a common point of debate between engineers and producers. The engineer will want the producer to track out the beat and take off all the reverbs, and the producer will say, "No, that's the effect!" There's a reason for this.
Should we use it as a send effect—sending all of our sounds to a single reverb? Or should we use it as an insert effect on individual tracks?
The first thought that comes to mind is, "Computers today are fast enough. There's no need to reserve processing power. We can just slap reverbs on everything, especially with a fast enough computer." While it's true that adding reverb to every track can make something sound more immersive, there's a crucial reason why using reverb on a send is the tried-and-true technique used by engineers for decades and a cornerstone of a polished, cohesive mix.
Here's why:
1. Cohesion and Shared Space
Imagine your mix is a band playing in a concert hall or a gymnasium. Using a single send reverb is like placing all your instruments in that same physical space. Each element feeds into that same reverb, so they all share the same acoustic environment. This "shared tail" acts as a sort of glue, binding the different tracks together in a unified way. It's one of the most powerful things you can do to make your mixes sound cohesive.
If you decide to use a reverb on every individual track, it's like each musician is playing in their own room. Even if the settings are similar, the individual reverbs will have subtle variations in decay and modulation. This can make the mix feel more like a collage of elements rather than a cohesive song played by one unified group. If too much of this is going on, it can be highly disorienting for the listener.
2. Phase and Frequency Build-Up
One of the biggest culprits of a muddy mix is the build-up of low-end frequencies. When you insert multiple reverbs, each instance generates its own stereo image, phase characteristics, and reflections. The overlap of all of these can create unpleasant comb filtering or a low-frequency wash, especially with many instruments using a high wet/dry mix.
If you use a single send reverb, you control the blend from one return channel, so all of the phase interactions are predictable. You can also easily roll off the high or low end with an EQ on that send track, preventing the reverb from cluttering up the mix and leaving space for the kick drum and bass.
3. Efficiency and Workflow
Imagine you're about 90% done with a mix and you decide that the reverb is too dark. If you used inserts, you'd have to go to each one of those tracks and adjust the EQ on each reverb—a tedious and time-consuming process. Ultimately, if you're the engineer, you're wasting a client's time, and if you're the producer, you're wasting your own time in the studio.
With a send reverb, you can change the entire reverb with just one move. You can EQ, compress, automate, or gate the reverb on the auxiliary track without having to adjust any other instruments. If you need to pull an instrument back in the mix or move it around, you just adjust the send level.
The Hybrid Approach: Best of Both Worlds
Even with all of this being true, there are still instances where certain elements may just sound better with a dedicated reverb. So, here's what you can do—this is what I do: I'll have one or two reverbs that are my main space, and then for individual elements that I want to move around, I'll put a dedicated reverb on those tracks. Typically, it's not going to be more than one or two elements that I'm doing this with. Everything else can go to the main space.
This way, you get the best of both worlds: the glue of a shared room and the character of a unique space where it counts. I can create mixes that have that three-dimensionality and are still CPU-resourceful.
Ultimately, I understand if you're one of those people who's using reverbs on everything or leaving the reverbs on your instruments in the mix. If it sounds good, don't change it. However, if you're running into phase issues, low-frequency mud, or having a hard time placing things in the stereo image, then take advantage of early reflections and use sends for reverbs.
If you're working with something and you want the ability to place itforward and backward in the stereo field, then having a reverb on that instrument is a completely valid approach. Early reflections do create a sense of depth and space, especially when tied to an instrument's panning and tone, which results in a very integrated sound for that single instrument. However, remember that when you do this, you are trading off a little bit of that uniform glue for that specific sound.
If you understand how to do both, you can utilize these two techniques simultaneously to get a very three-dimensional mix without having any phase issues or low-end mud. So if you appreciate this, make sure to share it with somebody who can benefit from this information.