Bluetooth technology has come a long way since its humbling days as a wireless communication protocol that transfers data between mobile and fixed devices. Today, it’s a ubiquitous technology applicable in almost all hi-tech use cases. The number of peripherals that use Bluetooth to communicate is immense — wireless keyboards, headsets, video game controllers, mice, you name it.
The audio side of Bluetooth, in particular, has received tremendous headway. Part of what led to this development was the incorporation of new audio codecs. In a basic sense, an audio codec is an algorithm that compresses and decompresses audio signals. The main objective of audio codecs is to produce high-fidelity sound at the least amount of bits without compromising quality.
Two popular codecs used for Bluetooth audio are aptX and AAC. Both promise high-quality audio and use advanced algorithms to manage the bitrate of the audio stream. As such, they ensure they achieve the highest possible audio quality while reducing the file size.
However, some differences exist that make one codec technology better. This article examines AptX vs. AAC codecs in greater detail. We’ll appraise their encoding methods, technical specifications, and performance characteristics to bring to light the best.
AptX vs. AAC: Side-By-Side Comparison
The following table overviews the technical specifications comparison between AptX and AAC.
|Sampling rate||44.1kHz, 48kHz||8kHz to 96kHz|
|Latency||1.8 ms (@48kHz)||60 ms (@44.1kHz)|
|Compatibility||Android devices, Some Windows devices||Apple devices, some Windows devices|
|Maximum Bitrate||325kbit/s (@ 48kHz)384kbit/s (@ 48kHz)||320kbps|
AptX vs. AAC: What’s the Difference?
Incorporating codecs in Bluetooth was a major milestone in wireless audio technology. While these technologies changed how we consume Bluetooth audio, they use different methodologies that yield varied results. We’ve already established a few discrepancies from the above table, which we’ll discuss in greater detail in the following sections. However, first, let’s have a brief overview of aptX and AAC.
AptX vs. AAC: Overview
AptX is a proprietary codec technology developed by Qualcomm. The abbreviation aptX stands for audio processing technology. It uses a lossy compression algorithm that reduces audio size without affecting audio quality. This technology finds use in various audio applications, including TV audio, music streaming, and video gaming. As a bitrate compression
On the other hand, AAC is an open-source codec often used in multiple audio compression applications. AAC is an acronym for Advanced Audio Coding. Unlike aptX, AAC finds common use in streaming audio over the internet. However, people also use it for digital radio broadcasting, mainly compatible with iOS devices. Below are the differences between aptX and AAC.
Sampling Rate and Bit Depth
The sampling rate is a crucial metric in digital audio codecs because it determines the frequency or how often an analog audio signal converts into a digital signal after sampling. Basically, it’s the number of times per second either aptX or AAC records a sound wave and converts it into a digital signal. Normally the higher the sampling rate, the more samples in a second are taken.
What comes out of this is a more accurate representation of the original sound wave. A higher sampling rate captures more nuances in the music files, including subtle changes in volume or pitch.
Another crucial metric is bit-depth. This metric determines the member of bits used to represent the amplitude of an audio signal. In the case of audio codecs, bit depths help establish the level of detail with which an audio signal is compressed.
More clearly, a higher bit-depth in an uncompressed audio signal indicates that the codec has the potential to represent the audio signal during compression more accurately.
Now back to aptX and AAC. Both support a bit-depth of 16 bits of data meaning that each sample is represented using 16 bits. This bit-depth is sufficient for most applications, but some high-end applications that desire more accuracy and detail may require relatively higher bit depths.
AptX supports 44.1kHz and 48kHz, whereas AAC supports a sampling rate of 8kHz to 96kHz. AAC can support a broader range of audio formats, including those that require a higher sampling rate. These higher rates presented by AAC mean that the audio quality can provide better sound quality.
Bitrate is basically the amount of data that transfers over a Bluetooth connection per second. Maximum bitrate is the highest amount of data that can do so within a second. AptX and AAC have varied bitrates.
AptX has a maximum bitrate of 352kbps, meaning the highest kilobits it can transfer over a Bluetooth connection is 352 every second. Technically, this is a high-quality bitrate sufficient for most applications, including streaming music over Bluetooth. This high bitrate reduces audio data compression, resulting in better sound quality.
AAC supports a maximum bitrate of 320kbps, which is high enough for most high-end applications. While it’s lower than aptX’s, AAC is synonymous with high efficiency in compressing audio data. Basically, it can disseminate high-quality audio data at a relatively lower bit rate than aptX, giving smaller sizes and less strain on the Bluetooth connection.
However, it’s crucial to note that various factors affect the bitrate when transferring data over a Bluetooth connection. These factors include the quality of the Bluetooth connection, available bandwidth, and audio signal. Another factor is the complexity of the audio signal.
In the context of audio codecs, latency is the delay of an audio signal transmission between the source and listener. This parameter is crucial because it impacts the general user experience, especially in applications where real-time audio is paramount. Such scenarios include gaming, live performance, and video conferencing.
AptX and AAC immensely vary in latency. AptX has a latency of 1.8ms at a sampling rate of 48kHz. This low latency makes it an ideal choice for real-time audio applications.
The delay between the audio source and the recipient is minimal; thus, there’s a seamless and natural listening experience. AptX achieved this low latency using its proprietary algorithm that reduces the delay between the dissemination and reception of the audio signal.
AAC’s latency is quite high, 60ms at a sampling rate of 44.1kHz. As such, there will be a noticeable delay between the time of dissemination and reception, resulting in a less seamless and natural listening experience. This high latency in AAC is because of the complex algorithms that use more time to encode and decode the audio data.
AptX and AAC have different levels of support regarding devices. About all smartphone devices using Android 8.0 or higher support aptX. Additionally, this audio codec is natively supported on several platforms, including snapdragon 845 and higher. We can say it’s an Android friendly codec.
On the other hand, AAC inclines more to the Apple ecosystem. All iOS devices, including iPads, Mac computers, and iPhones, support AAC natively. Other applications like YouTube and consoles like PlayStation and Nintendo support AAC codec.
AptX vs. AAC: 6 Must-Know Facts
- AptX has a maximum bitrate of 384kbps, whereas AAC has a maximum bitrate of 320kbps.
- AptX is light on the processor, thus faster, whereas AAC is quite processor-heavy, which makes it relatively slower.
- AptX is mainly used on Android version 8.0 and higher, whereas AAC is most used on iOS and Mac devices.
- AptX supports HD audio with sampling rates of up to 48 kilohertz, whereas AAC offers sampling rates ranging between 8 and 96kHz.
- AptX has a low latency of 1.8ms at 48kHz, whereas AAC’s latency is quite high at 60ms at 44.1kHz.
- Both have a bit-depth of 16 bits of data.
AptX vs. AAC: Which One is Better? Which One Should You Use?
The choice of codec to use depends on various factors. In most cases, the codec you choose will depend on your intended use of the signal, your preferred sound quality, and the device being used. Both have strengths and weaknesses that make one a more desirable option than the other.
If you own an Android 8.0 or higher, you are better off with an aptX codec. Also, it has a low latency that ensures high-quality audio data transmission with minimal compression artifacts. As such, it’s an ideal solution for real-time audio use like gaming and live performance. Because of the low latency, aptX also assures you of a seamless listening experience that is technically better than AAC.
If you use an Apple device or one that uses the iOS operating system, AAC is the ideal codec to use. This codec is synonymous with its high-quality compression algorithm that delivers sound quality with minimal data loss. As such, it’s a popular choice for streaming services and other applications with limited bandwidth. Ultimately, the choice depends on your needs and use case scenario. However, if you have the option, it’s worth experimenting with both codecs to establish the one that delivers the best sound quality.
The image featured at the top of this post is ©Mix and Match Studio/Shutterstock.com.