Plugin Usage Explained - CPU/RAM/DSP
Have you ever had a project start to crackle and glitch while you were working on it? You're not alone!
This issue has been around long before the invention of mobile devices and we're going to show you how to resolve it and try to explain why it happens in the first place.
Plus there seems to be some confusion in the space as to what the CPU and RAM actually do and and how they relate to the plugin performance inside your DAW (Digital Audio Workstation) so we'll try to break that down as well.
Let's talk about CPU first, what is it and what does it do? CPU stands for Central Processing Unit and is considered to be the brain of the device. This is the onboard chip that processes your audio in real time. Newer devices will always have faster CPUs than older devices as technology progresses ever onward.
Most DAWs will provide you with both a CPU and DSP meter letting you know how much processing power you're currently using. The CPU meter will never be at 0% though (at least in Cubasis on iOS) because the CPU still has to process the operating system and the DAW itself in addition to any real time processing that takes place once you hit play.
The faster your CPU the more DSP your device can process in real time.
And what exactly is DSP? DSP stands for Digital Signal Processing. The level of DSP you're generating will determine how hard your CPU has to work. Adding more plugins will create more DSP for your CPU to process. If your DSP levels reach to high you will hear that very famous crackle, stutter and glitching in your project that will make it impossible to complete until the DSP is lowered.
It's important to note here that not all plugins are created equal. Some are more efficient than others requiring far less DSP for your CPU to process allowing you to have more instances of them running in your project.
Typically stock plugins or plugins that come with your DAW take up the least amount of resources. 3rd party plugins can be optimized as well but generally 3rd party effect plugins like delays, reverbs and tape machines are usually the most DSP hungry when compared to sound shaping plugins like EQs and Compressors.
That brings us to RAM. RAM stands for Random Access Memory. We'd like to point out here that both CPU and RAM are equally important but they're important for different reasons. You will however need more of both to be able to work on larger and larger projects with more and more plugins.
There seems to be some confusion in the community that is leading people to believe that just adding more RAM alone will allow you to run more tracks and more plugins in your project. This is actually not true and here's why. RAM simply acts like a temporary storage facility holding onto things that need to eventually be processed by your CPU, but RAM doesn't actually do any processing itself.
Adding more RAM will only allow you to store more tracks and plugins in memory, but you'll still need a faster CPU to process those additional tracks and plugins once you actually hit play. Adding more RAM will NOT decrease the amount of DSP your CPU will need to process. In other words the only thing that will allow you to process more DSP is a faster CPU.
How To Lower DSP And Reduce Crackling
If you can't afford an iPad with a faster CPU at the moment there are still some tried and true ways to reduce your DSP load and thus remove any annoying crackling and glitching. The first way is to "Freeze" your tracks. This simply converts your MIDI track into audio removing the need for your CPU to process any real time effects leaving only the raw audio left for the CPU to worry about.
The second best way to reduce your DSP load is to use the most efficient plugins possible. This doesn't just mean using more stock plugins but choosing which 3rd party plugins you do end up using very carefully. The best way to find out how much DSP a plugin requires is to simply test it out and use it. If you do find it's using too much DSP then either freeze the track or replace it with a more efficient substitute, or both.
The third best way to reduce DSP levels is to use Send Effects. Cubasis allows you to either add plugins in your Insert Effects slot or the Send Effects slot. Plugins placed in Send Effects have the advantage of allowing multiple tracks to use a single instance of them simultaneously whereas plugins placed in the Insert Effects slot can only be used by that one track. Plugins commonly placed in the Send Effects slot are delays, reverbs and choruses where the Insert Effects are typically reserved for sound shaping plugins such as EQs and Compressors.
Why the M1 iPad Is Important
In April of 2021 Apple revealed they would be bringing over their incredibly fast next generation processors to the iPad. This has signaled to the world that Apple is deadly serious about making the fastest mobile devices on the planet. And since having a fast CPU is an absolute priority for real time audio processing music producers around the world rejoiced to hear this reveal.
Because we now know how serious Apple is about keeping their mobile devices as competitive as possible music producers can presume that more software and hardware manufacturers will pay attention to the iOS platform in the coming years and allocate more and more resources to this space.
Apple commiting the M1 chip to their iPads is truly a game changer for mobile music producers and the fact that the M1 iPads can currently only utilize around 5gb of RAM per app is almost irrelevant when you truly consider how much faster the M1 is compared to previous mobile CPUs and thus how much more DSP it can handle than its predecessors. Plus the iPad already comes with more than enough RAM to hold far more plugins than its CPU could ever process in real time anyway.
Now we hope we explained some of these technical details in a way that made sense to you as a music producer. Alot of this stuff can certainly get confusing but once you wrap your head around it should all make sense. The main takeaway really is that you’ll need as much RAM and CPU as possible for your music production. Your RAM determines how many plugins and tracks you can have in your project and your CPU determines how much DSP you can process at once, or in other words how many of those plugins/tracks you can run in real time once you hit play. So if you do see your DSP meter climb to high make sure to freeze some tracks and use send effects wherever possible.