Adding Warmth to Software Synths

What is warmth, really? So many people use this word to describe a sound, but what does it actually mean? Are they talking about a certain frequency? A presence? A fullness of tone? Warmth is one of the most difficult terms to articulate because it can mean so many different things to different people. Some people swear by the “warmth of analog gear, vinyl records and tube amplifiers,” for example. For the sake of this conversation, I am defining warmth as the feeling you get when a sound draws you in, invites you into a space and makes you feel warm. It’s a broad description so interpret it as you see fit. When I want to add warmth to a sound, I want it to feel analog, real, and uniquely human. Like many of you, I use primarily soft synths when I am writing and producing music. The affordability, portability, and flexibility make soft synths super useful. I have a ton of love for hardware synths and modules but I’m most often reaching for something “in the box” to move quickly and keep the creativity flowing. In this article, I’m not advocating for or against any particular workflow or piece of equipment. I am, however, encouraging you to think beyond software presets and your normal way of working to create new and interesting sounds.
 
The Synth
Let's start with a simple pad sound. Feel free to pull up a synth pad or string preset in your favorite DAW. Or, if you’re a bit more adventurous, you can build your own synth with, let's say, two oscillators (a sine and a saw that are polyphonic, for instance) followed by a filter. The goal here is to have a basic sound that you like, but that you know could use some character to make it really stand out. I’m going to share with you my favorite techniques for doing just that - adding warmth and vibe to this sound using plugins that are available and included with most DAWs. They don’t have to be expensive or boutique (although those are great, too). It's all about how you use them. 
Here is my synth pad, totally dry, for you to hear as an example.


EQ
One of my favorite plugins to reach for first is EQ. I know this may seem obvious, and, it is! The beauty here is that you can really impact the sound of your synth by doing a simple low cut, a high boost or some combination of the two. Sometimes the synth I am working with has a great sounding filter of its own but I can’t get the kind of detail that I can with a fully sweepable, multiband parametric EQ with an adjustable Q. The other thing that I love to do with my EQ is set fairly steep high or low pass filters and experiment with what I refer to as “bandwidth limiting,” or limiting the frequencies in which the synth is working. If you roll off everything below 300hz, for example, you will have a much different sound than one that includes all of the sonic information below 300hz. Sometimes the opposite is necessary to make your synth feel warmer and maybe less bright or harsh. Try taking away everything above 1 or 2k and listen to what’s left. When applying EQ, I start with extreme moves that will noticeably shape my sound so that I can really get a sense of what’s useful. Making small moves is great when you’re mixing an already dialed in sound but when you’re creating the sound from the beginning, be bold!
In the example below, I have rolled off everything below 174hz, added a 1.3 dB dip with a Q of 2.0 at 380hz and a 4 dB dip with a Q of 1.7 at 740hz. Notice how my sound is thinner in the low end but also smoother overall.
 

Compression
Another great way to shape your soft synth sound and add warmth and vibe is by the creative use of compression. I say creative use because I’m not talking about using compression to control transients or smooth out a performance. Since we’re using a pad in this case there will be few transients and dynamics to control anyway. I am talking about using compression as a tonal tool. As with my use of EQ, I start with extreme settings to get a sense of what is possible. Try setting your ratio to 12:1 or even 20:1 and crank your threshold down to minus 20 or 30 dB and listen to what your synth sounds like. It probably sounds a lot more intense and gritty than it did before. When I’m working with pads I like to, at times, have 5-10 dB of reduction happening constantly. This use of compression will not only change the dynamics of your sound but it will alter the tone altogether. Keep your EQ engaged and experiment with the interplay between your EQ and your compressor. I like to put my EQ before my compressor so that I’m compressing the new sound that I’ve created with my EQ. This isn’t a hard and fast rule by any means, so also try swapping them and listen to the results. If you have a multiband compressor, experiment with that in this spot as well. 

In this example, you will hear the intensity brought on by my compressor, which is set with a ratio of 20:1 with constant gain reduction of 16 dB. Notice the slight pumping sound on the longer sustained chords - if this sound is part of a larger production, this slight rhythmic variation may add some nice movement to the arrangement.
 
 
Distortion/Saturation
If I have a sound I like as a result of EQ and compression, next I’ll add some form of distortion, overdrive or saturation. Sometimes this is the first thing I will insert and at times, may be the only thing I use, especially if DSP is a concern. Many synths actually have a distortion circuit built into them, which is handy if you want to hear what adding some more harmonic color to your synth will sound like. Unlike my EQ and compression techniques, I tend to use distortion and saturation more sparingly, as a little goes a long way. If you’re looking to add a ton of dirt or grit to your sound, go crazy here, but if you’re just looking to add a bit of warmth, try using small amounts of distortion first. Listen for how your sound is becoming more saturated and complex harmonically. Another great option for this application is a basic tape saturation plugin. There are compression characteristics as well as EQ changes that happen as a result of tape saturation. This is another simple, one-stop-shop if you are short on time or DSP resources. Try several different types of harmonic plugins here as distortion vs overdrive vs saturation will all impact your synth differently. 

In this example, I’ve added some drive, crunch and a little bit of low end back in with my distortion plugin. Once again, the change is subtle but noticeable. Since I removed all of the frequencies below 174hz with my EQ, the low end that is being generated by the distortion plugin has more of a white noise quality to it, as it is being created somewhat artificially.


Bit Reduction
Another simple but mighty way to add some much-needed vibe to your synth sound is by using bit reduction. If you are working on a modern DAW, your sample rate and bit depth are probably at least 44.1khz and 16 bits and may be as high as 192khz and 32 bits. This resolution, while offering incredible clarity and detail, can at times lead sounds to feel a bit sterile and cold. A bit reduction plugin can take the resolution of your audio down to 8 bits, for instance, which will add a bunch of grit and noise to your signal. A little goes a long way, so be judicious in your application here.
Below you will hear that I added just a touch of bit reduction. There’s a lot happening in the plugin that is creating some really cool high overtones, but I want just a tiny bit of that sound, so I have my mix knob set at 5%.
 

Chorus and pitch shifting
My final go-to when I’m looking to add warmth is either a chorus plugin or a pitch shifting plugin. A subtle shift in the pitch or timing of my synth can make a huge difference in terms of vibe and character. Again, many hardware and software synths have a chorus effect built into them, so feel free to start there. I like using a plugin version so that I can put it anywhere in my signal chain. Having chorus inserted after my tape saturation plugin, for instance, will sound very different than if I have it inserted before my saturation. Since chorus is essentially creating a double of my sound that is slightly delayed and pitched up or down, a doubler or pitch plugin can be great in this application, too. Don’t be afraid to try several plugins to find the ones you like. It may end up being something different than you would have thought! I recommend using a chorus or pitch plugin that has a mix knob so that you can keep as much of the original sound intact as you want and just add the amount of effect that feels right to you.
In this final example, I’ve added a little bit of chorus to the existing sound. You’ll notice that the pad is a bit wider and sounds a bit thinner. Adding chorus can often help sweeten your sound, especially if the distortion or bit reduction plugin has added grit or overtones that you want to smooth out.



Application/Experimentation
As with all things creative, experimentation is key. Even though I detailed a particular signal flow above, try different signal flows and combinations of these plugins. This is how new and unique sounds are discovered! Sometimes all you need is a bit of EQ or chorus to make your pad come to life! Have a great time creating and share what you discover below in the comments!