When working with audio interfaces (or external sound cards), problems with crackling are some common concerns. Typically, we hear things like crackles, whether recording with a mic or listening.
If you too are experiencing this kind of noise with your external sound card (for example, your Focusrite 2i2), don’t worry: it is not faulty, but several things will need to be fixed.
Because yes, there are different possible solutions to the problem — or at least different actions that can be taken to eradicate these audio interface crackles, which are annoying for computer music, recording, and mixing.
In this article, we will see in detail different strategies that can be put in place to correct the audio interface crackling problem.
Why Does My Audio Interface Crackle
Before implementing any corrective action or update to reduce crackling sound from your audio interface, it is important to understand what is causing it entirely.
This will allow you to choose more appropriately what you are going to do to remove them.
What happens when you work on your computer with an audio interface?
Well, necessarily, the two devices communicate with each other – via USB. For example, they exchange data concerning the audio signal, which must be recorded and/or played.
Although you may think that everything is happening in real-time, it is not: neither the interface nor your computer can do everything at the same time.
As a result, a number of small blocks of memory called buffers are used to store audio data — typically located in RAM.
There will always be a latency between the moment when you play a note and the moment when it is recorded on your computer.
Let’s imagine that you are recording something (your voice, your guitar, etc.) via your audio interface, and let’s look at what is happening in a simplified way:
- Your interface converts the analog audio signal into a digital signal;
- data packets (and therefore signal) are deposited in turn in a buffer ;
- the computer accesses this buffer, retrieves the data, and stores it on the hard disk.
And conversely when you are listening to your production:
- the computer places a first data packet in a buffer;
- this buffer is retrieved and read by the interface;
- the computer comes to deposit a second packet;
What if the computer is not fast enough to retrieve or deposit these data fragments? Ah yes, here is when the famous crackles in the sound of your audio interface happen!
Crackles are very visible on the waveforms you have recorded:
Note on the other hand that the computer’s speed is not only linked to its power: the driver’s efficiency, that is to say of the program which precisely makes it possible to carry out the processes explained above, is there for many.
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Some manufacturers offer very well programmed / efficient drivers, such as RME.
In others, the drivers are slower and more prone to crashes: this generally results in crackling in the audio signal.
Below you will find some solutions to why does your audio interface crackle.
The usual suspects: buffer and sample rate
If you experience crackling with your external sound card (regardless of the DAW: Cubase, Reaper, Ableton Live, Studio One…), various actions can be taken to eliminate them.
Indeed, it is not tolerable to have this type of crackling when you listen to your production, even less if you record. Here are some solutions:
Adjust the buffer size
Your very first instinct should be to increase the size of the buffers — the very ones we were talking about a little earlier.
Indeed, the smaller the buffer, the faster the computer will have to be. And the more cracks there will be.
Increasing the buffer, therefore, allows your PC or Mac to breathe a little, at the expense of greater latency.
To adjust the buffer size, you generally have two options: through your DAW or through your audio interface software.
Through your DAW
When you are in your DAW, it is always possible to access an audio settings panel communicating with your interface.
The exact names will change depending on the software, but for example in Ableton Live, you can do Options > Preferences > Audio to access the following panel.
By clicking on the “Hardware Config” button, the configuration window for the software associated with your audio interface opens. You can then adjust the buffer size.
I advise you to go gradually: if your buffer is 64 samples and you have audio interface crackles, go to 128.
Are there still crackles? Go to 256 samples, the size just above. And so on…
Note: I have already had the case, counter-intuitive, where decreasing the size of the buffer made it possible to reduce the problems with the signal. It’s rare, but some drivers have trouble with very large buffers…
Note: some DAWs include options to reduce latency via a particular technology. If you are having crackling issues, try disabling these options first: sometimes they work just fine, but in some cases, they can do more harm than good.
Through your audio interface software
Most of the time, your audio interface comes with software, which you have probably downloaded, which allows you to modify the buffer size.
Generally, it is this software that is launched when you adjust the buffer from your DAW.
The interface can be more or less modern, more or less complex, but you will always find the appropriate setting.
For example, with the Focusrite Scarlett interfaces, the brand offers a tool called Focusrite Device Settings, which allows you to make the desired adjustments.
Adjust the sample rate
The problem with increasing the buffer size — as we have said — is that it has the effect of increasing the overall latency. If it does not pose any particular problem during playback/mixing, it is still more annoying during a recording phase.
A simple option, and directly accessible from the same panel as the buffer setting, is to adjust the sampling rate.
Indeed, this has a direct link to latency: the higher the sampling rate, the lower the latency.
But the more the processor (CPU) of your computer will be solicited.
We can therefore say that there is a good balance to be found between buffer size and sampling rate.
However, especially if your computer is not very powerful, I would advise you to stick to the sample rate you want to work with (typically 44100 Hz for CD quality), and just play around with the buffer setting. to avoid stressing your CPU.
And if after these first steps you still hear crackling when using your external sound card, then read on, there are still things you can do to improve the performance of your interface!
Reduce audio crackling by updating your software
A number of cracking issues can appear when your tools aren’t quite up to date.
Casually, between the first and the latest version of the software, there can be big differences in performance.
If playing with the size of the buffer did not allow you to annihilate the crackling of your interface, I advise you to check that you have correctly updated your tools.
Besides, even without crackling, it’s rather a good practice…
Update the firmware of your audio interface
Let’s start by looking at the audio interface itself. Indeed, it has its own software, which is installed on the integrated circuits it contains.
This is called “firmware”, and it is essential to ensure that it is up to date.
Even if you have just purchased your interface, there is no guarantee that the latest firmware version is correctly installed.
So, what to do?
The procedure is generally quite simple (and is described in the manual of your interface):
- either the manufacturer of your interface has integrated a firmware update feature, which launches automatically or which you can trigger manually;
- or you can get the latest firmware version directly from the manufacturer’s site.
Often, the firmware update is done via a very simple utility with a simple “update” button.
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Audio driver update
99% of interfaces are delivered with drivers provided by the manufacturer.
It is, therefore, necessary to make sure to use and keep these drivers up to date so that they remain compatible with the new versions of the operating systems (Windows, Mac OS, etc.).
Again, the procedure consists of going to the manufacturer’s site to download the latest version and install it.
Normally, it’s not necessary to uninstall the old version — but you can do so to ensure that the installation is as clean as possible.
Updated DAW and plugins
It’s not just the interface and its drivers that need to be up to date!
Indeed, all of your software is likely to create performance problems, which often result in audio interface crackles.
So make sure you have the latest version of your DAW and plugins.
Finally, updating your operating system can also be a good idea.
However, it can be a double-edged sword, in the sense that we have already seen problems appear following a Windows update, for example.
That said, as far as I’m concerned, my PC running Windows is always up to date, and I’ve never encountered a problem.
Check the hardware part
Most of the time, crackling or crackling problems with audio interfaces are related to the software part: incorrectly set drivers, not updated, etc.
However, specific hardware problems may have an impact on the behavior of your interface.
Here are some ideas of things you can check/try:
The cable and the interface
Visually inspect your USB cable and connector at the interface:
- is the cable in good condition?
- Is there dust on the connector?
- When you plug/unplug, does everything look normal?
In short, check that physically everything looks normal.
Avoid USB hubs
Today, especially if you are a laptop user, the temptation is great to use a USB hub.
However, this may simply be the cause of your crackling problems: in fact, the hubs will share the electrical current between several devices in a certain way.
Depending on what is plugged into your hub and its quality, it may no longer be fast enough for your audio interface.
A solution exists with “active” hubs, that is to say, powered by the mains. However, be careful with this type of hubs, too: depending on the electronic grounding circuit, they can create ground loops — and therefore create other types of audio problems (background noise, snoring…).
In short, you will have understood: by default, if you have the possibility, I recommend that you plug your audio interface directly into one of your computer’s USB ports.
Try another USB port.
Depending on your motherboard and how your computer’s components are mounted, some USB ports may be more efficient/faster than others.
There are tools and techniques for making measurements, but that is not quite the subject of the article: that said, if you are having sound problems with your audio interface, I advise you to test the other USB ports on your computer.
In some cases, the difference in performance can be significant.
Clean up your computer
We often underestimate the impact that dust infiltrating our computers can have.
However, it can reduce their lifespan, but it can also significantly impact performance.
Indeed, a lot of dust = the fans have a harder time cooling the case = it gets hotter = the processor is potentially less efficient.
So don’t expect cleaning your computer to double performance either — but cleaning it regularly (once every 6-12 months) seems like a good practice to me.
Optimize CPU and disk management in your DAW
At some point, despite the various optimizations you can make in the buffer settings and on your PC, you may still encounter problems — especially on sessions with a lot of plugins and a lot of tracks.
Fortunately, different approaches allow you to save system resources.
Freeze your tracks (or: the Freeze function)
A large number of DAWs incorporate what is called a track freeze function.
It is designed precisely to relieve your computer and avoid the audio interface crackles and pops you may have.
Indeed, when you freeze a track, it is exported to the hard disk in an audio format.
That is, instead of having a track with all your effects or virtual instrument plugins, you end up with a classic audio track — much less demanding of CPU or RAM resources.
And of course, the process is designed to be temporary and reversible: you can unfreeze a track at any time to make changes to it.
Adjust your plugin settings
Then, directly at the level of the plugins you use, some settings are likely to require a lot more computing power.
Start, of course, by deactivating or removing unused plugins, if there are any.
Next, see if any of your plugins have an oversampling option enabled.
Oversampling is a sampling technique used when programming plugins to avoid aliasing phenomena.
If it is essential to have a quality sound (I am thinking of distortions and amp simulations), this algorithm can be very resource-intensive.
For example, with Mercuriall’s excellent Euphoria amp simulation :
- without oversampling, I’m at 10% CPU usage;
- With an 8x oversampling, I go to 29%!
I, therefore, advise you to deactivate oversampling on your plugins when you are working and only, of course, if you hear crackling.
On the other hand, don’t forget to reactivate it during the export to take advantage of this feature and optimize the sound quality!
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Windows: a few simple actions to avoid audio interface crackling
For Windows users at least, specific actions independent of the DAW can be carried out to optimize the computer’s performance and therefore be able to allocate more resources to audio processing.
Close other programs
If you have audio cracking problems, it is essential to start by closing all software that could be running in the background.
Close all open windows, but also check among the icons at the bottom right of your screen that you do not have software that would be launched for nothing:
- Gaming applications such as Steam, Epic Games, etc.
- Cloud applications such as OneDrive, Google Drive (don’t forget to reactivate them after your MAO session, however)
Turn off visual effects.
Make sure to disable any visual effects that your computer may generate.
Typically, on Windows 10, it is advisable to disable window transparency effects.
To do this :
- Right-click on your desktop and choose the Personalize option.
- Go to the Colors tab
- Uncheck the Transparency Effects box
Remove any widgets/modules showing on your desktop if you use any.
Disable wifi and Bluetooth
In many studios, the PC(s) used for recording are not connected to the Internet. This potentially avoids some viruses, but it also has the advantage of maximizing system stability.
Indeed, everything that is wifi and bluetooth necessarily consumes part of the computer’s resources.
Except, in most cases, we don’t need to go on the web when we work on our songs.
If you have issues with audio crackling, try temporarily disabling both of these features. On Windows 10, an easy way to do this is to enable airplane mode.
Adjust power options
Especially if you are on a laptop, it is essential to check that the power options set by default on your computer do not lower its performance.
Go to the Control Panel, display the complete icons instead of categories (selector at the top right of the window) and click on Power Options.
A window will appear with a list of power plans.
Whether it’s to produce, record, or mix a song, you need to have as many resources as possible available.
It is then necessary to ensure that the High-Performance mode is selected.
Then click on Change mode settings and change the two settings that appear (Turn off the screen and Put the computer to sleep) to Never.
Then you can go even further by adjusting the advanced settings ( Change advanced power settings) :
- CPU power management: make sure all settings are at 100%
- Hard disk: set disk shutdown option to “never”
- USB Settings: Disable Selective Suspend
A few other ideas…
Here are some other simple actions you can take:
- defragment your hard drives, except, of course, if they are SSDs ;
- disable system sounds;
- disable your antivirus (if, of course, your computer is isolated from the rest of the world).
LatencyMon: the ultimate tool against audio interface crackles?
And now I’ve saved the best for last since there is software to check if your computer is suitable for real-time processing audio — and therefore for computer music, recording and mixing. .
This is LatencyMon, a utility from Resplendence.
There is a free version and a paid version of LatencyMon.
Objectively, the free version will be more than enough in most cases since it already provides valuable information.
So go to this page grouping the brand’s software, find LatencyMon in the list, and click on “Download Free Home Edition.”
Install the program like any Windows software.
Run your first test
The operating principle of LatencyMon is quite simple:
- Launch the software
- Click on the neon green arrow symbol (“Start Monitor”)
- Wait a bit for the analysis to take place
- Click the red square symbol to stop the scan
- Look at the results in the different tabs.
I advise you to do two tests, in both cases just after starting the computer:
- a first, “empty,” without having launched an application manually;
- a second, this time with your DAW open and playing one of your songs.
In theory, the second test will allow you to confirm the results obtained with the first.
Also, make sure to leave as much time as possible for the analysis to be as precise as possible: at least 5 minutes, but don’t hesitate to let the software run for 15 minutes.
The synthetic report
Once the analysis is done, start by looking at the “Main” tab.
This offers you a synthetic summary of what has been measured, as well as a concluding sentence.
It can be red, letting you know that something is wrong — or it can be green like in the screenshot below, letting you know that everything is fine.
Roughly speaking, this conclusion is based on the four execution times of the so-called DPC and ISR routines:
- if they are lower than 2 milliseconds (2000 µs), the software will consider that everything is fine and that your PC will be able to manage the audio in real-time;
- between 2 and 4 milliseconds, the software will consider that there is a doubt;
- And above 4 milliseconds will tell you that there is a big problem.
Note: there is a theory and real life. LatencyMon may give you a positive result (thus, in green) while you hear crackles. Continue reading if this is the case; what follows will concern you too.
Fix high DPC and ISR durations
The DPCs and ISRs are routines that can run at any time, potentially on the same processor that the audio signal is on, creating pop-outs in the sound.
It is, therefore, important that these durations be as short as possible.
To see what generates these latencies, go to the “Drivers” tab of LatencyMon and classify the table by clicking on the “DPC” column or the “ISR” column.
Then identify the drivers responsible for the highest DPC and ISR durations.
If, for example, LatencyMon tells you that the tcpip.sys or ndis.sys drivers generate significant DPC / ISR latencies. This means that your network drivers are at fault. Try disabling the corresponding devices (see the explanation on the Device Manager a little earlier in the article), then redo a measurement.
If you don’t know what a driver’s names stand for, a Google search of the driver’s name and/or description should bring you the answer.
Be careful not to disable something you don’t understand the purpose of!
Note: instead of or in addition to the DPC/ISR duration analysis, you can also look at the drivers that generated significant execution times, a piece of information available on the same tab.
Try to avoid page faults.
A complex page fault occurs when an application uses virtual memory stored on a disk and not in RAM.
As you will have understood, these events are also likely to generate crackling or crackling in the audio signal of your interface.
Click on the “Processes” tab and classify the table by clicking on the “Hard page faults” column.
First, I advise you to take a look at the applications with many complex page faults: some may not have been executed (for example, an antivirus that scans your hard disk when you are making computer music …).
However, the most important thing is to search your audio applications to see if page faults have impacted them.
If this is the case, two main actions are to be recommended:
- Close applications that use a lot of RAM;
- Increase the RAM in your system.
That’s it; we come to the end of this article — which I hope will have helped you solve your audio interface crackling problems.
Do not hesitate to ask your comments if you need clarification on certain elements.