When you start home recording on Windows, you run into the word “ASIO” on the settings screen of your DAW (music production software). The driver options include several labeled “ASIO”, and many people are unsure which to pick. This article summarizes, for beginners and based on official materials from Steinberg, Microsoft, Apple and Focusrite, what ASIO is, why Windows needs it, how it relates to the manufacturer’s own driver, and how a Mac differs.
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Key points
- ASIO (Audio Stream Input/Output) is a driver standard for exchanging sound between an audio interface and software. It was created by Steinberg of Germany.
- Steinberg explains that ASIO is supported by the major audio interface manufacturers and is required by most professional music software on Windows. One reason is its low latency.
- The basic approach is to use the manufacturer’s own driver that comes with your audio interface. Steinberg also advises using the latest ASIO driver provided by the manufacturer.
- Once you have chosen ASIO, what determines the amount of latency is the buffer size. This is covered in more detail in “Fixing your voice sounding delayed while recording“.
- A Mac does not need ASIO. “Core Audio”, which Apple provides, takes on that role.
What ASIO is
A driver is a program that sits between the software on your computer and the connected hardware and acts as an interpreter. In the case of an audio interface, it sends the audio data the DAW outputs to the interface, and delivers the microphone’s sound to the DAW.
ASIO is the name of that driver standard. According to Steinberg, ASIO (Audio Stream Input/Output) is an audio driver standard that Steinberg itself developed. The major audio interface manufacturers support ASIO, and most professional music software on Windows requires it. One of the reasons is its low latency.
Latency is the delay between making a sound and hearing it in the headphones. When recording vocals, the smaller the delay, the easier it is to sing. The causes of delay and how to fix it are explained in “Fixing your voice sounding delayed while recording“.
Source: Steinberg official help (Steinberg built-in ASIO Driver: information & download)
Why Windows needs it
Windows has a built-in mechanism that mixes the sound of various applications and plays it together. That is why the sound of a browser, notification sounds and the sound of a video can play at the same time. But when sound passes through this mechanism, it goes through several stages of processing, and that creates delay.
Microsoft explains that before Windows 10 the delay from this processing was large. For example, before Windows 10, the delay on the output side was about 6 to 12 milliseconds depending on the data format. From Windows 10 onward, it is described as having dropped to 1.3 milliseconds. In addition, the delay of the buffer (the area that holds data) between the system and the hardware was fixed at about 10 milliseconds before Windows 10. From Windows 10 onward, it can be made smaller with a compatible driver.
On the other hand, Microsoft names ASIO as another way to reduce delay. When a user installs a third-party ASIO driver (one made by someone other than Microsoft), applications can send audio data directly to that driver. However, the application must also be built to support ASIO.
The standard Windows audio mechanism has also been improving. Even so, for home recording, the common choice is a combination of an ASIO-compatible DAW and an ASIO-compatible driver. Steinberg also explains that ASIO is widely required by professional music software on Windows.
Sources: Microsoft Learn (Low Latency Audio), Steinberg official help
How it relates to the manufacturer’s own driver
Audio interface manufacturers distribute ASIO drivers for their own gear. Here we call these “manufacturer ASIO drivers”. When you buy an interface, the basic step is to first install the latest driver from the manufacturer’s site. Focusrite also advises updating the driver in its checklist for when audio problems occur on Windows.
Steinberg’s “built-in ASIO Driver”
For hardware that has no manufacturer driver, Steinberg distributes a generic ASIO driver called the “Steinberg built-in ASIO Driver”. Steinberg’s explanation is as follows.
- It is a generic ASIO driver for Windows that works with a wide range of audio devices.
- Its main purpose is to let devices that do not support ASIO be used with Cubase, Dorico, Nuendo and WaveLab. The targets are mainly the sound chips on a computer’s motherboard. It can also be used with other ASIO-compatible software, but Steinberg explains that it can support only use with Steinberg software.
- It supports 64-bit Windows 11, Windows 11 on Arm and Windows 10. There is no 32-bit version.
- It is a newer driver, released in July 2023 together with WaveLab Cast 2. It will gradually replace the earlier “Generic Low Latency ASIO Driver”, which will not be developed further.
With this generic driver, you cannot change the ASIO buffer size (the amount of latency) from a control panel. Steinberg explains that even with a fixed buffer size, the latency should be low enough.
Steinberg writes that “in general, we recommend using the latest ASIO driver provided by the audio device manufacturer.” It also says that if your interface is not working well, trying this generic driver as an alternative is worthwhile. In other words, it is easiest to think of the manufacturer’s driver as the basic choice and the generic driver as a substitute.
Sources: Steinberg official help (Steinberg built-in ASIO Driver: information & download), Focusrite official help (Troubleshooting glitchy audio on Windows)
The link to buffer size
Using an ASIO driver makes it easier to reduce latency. But the actual amount of latency is determined by the buffer size. The buffer is time that the computer sets aside in advance to process sound. Here is a plain-language summary of Focusrite’s explanation.
- A smaller buffer means less delay. In return, the load on the computer increases and the sound is more likely to break up.
- A larger buffer means more delay. In return, the sound is more stable.
- It is fine to make it small when recording and large when mixing.
Where you set it differs by manufacturer. For Focusrite interfaces on Windows, you set it from the “Focusrite Notifier” icon in the taskbar. If the sound crackles or breaks up, Focusrite advises trying a setting of 1024. With other manufacturers, it is often set in the ASIO control panel or in dedicated software. Check the manual.
How to decide the buffer size, direct monitoring, and what to do when your voice sounds doubled are left to “Fixing your voice sounding delayed while recording“.
Sources: Focusrite official help (What is latency in audio?, Troubleshooting glitchy audio on Windows)
How a Mac differs: Core Audio
A Mac does not need ASIO. Steinberg explains that “because Apple has its own audio mechanism, Core Audio, ASIO drivers are not required on macOS.” For this reason, there is also no macOS version of the “Steinberg built-in ASIO Driver”.
Core Audio is the audio mechanism Apple provides. Apple’s documentation says that Core Audio is deeply integrated into iOS and OS X and delivers high performance and low latency. It also explains that audio signals are exchanged with hardware through a layer called the hardware abstraction layer (HAL). That may sound difficult, but it is enough to think of it as “the Mac itself has a standard doorway for exchanging sound with hardware.”
As a result, on a Mac:
- You do not need to pick a driver type from ASIO. You choose the audio interface in your DAW’s settings.
- Focusrite explains that on a Mac, you set the buffer size on the audio settings screen of your DAW.
Sources: Steinberg official help, Apple Developer (What Is Core Audio?), Focusrite official help (What is latency in audio?)
How to choose when you are unsure on Windows
- On the audio interface manufacturer’s site, find the driver for your model and install the latest version.
- In your DAW’s audio settings, choose “ASIO” as the driver type and select the ASIO driver that carries the manufacturer’s name.
- If the sound breaks up, raise the buffer size. If the delay bothers you, try lowering it.
- If your hardware has no manufacturer driver, or it is not working well, one option is to try Steinberg’s “built-in ASIO Driver” (supported only with Steinberg software).
Frequently asked questions
Q. Does using ASIO improve sound quality?
The official explanations covered in this article are about low latency (less delay). They do not say that sound quality gets better.
Q. Is ASIO included on a Windows computer from the start?
Microsoft describes ASIO as a way for users to install and use a third-party driver. Install the driver distributed by the maker of the interface you use.
Q. What should I do on a Mac if the delay bothers me?
Focusrite advises changing the buffer size in your DAW’s audio settings on a Mac. For other measures such as direct monitoring, see “Fixing your voice sounding delayed while recording“.
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