What is the difference between kbps and kHz?

I engage in the editing and export of audio files, and I’m curious to know if it is appropriate to export a 20kHz audio file at 320 kbps. I’ve provided an illustrative example through a spectrogram in Spek, which can be viewed here: spek example 20 kHz - Album on Imgur

While I understand that kbps represents the bit rate of the audio and kHz denotes the sample rate, recognizing their distinctiveness, I often rely on the spectrogram’s kHz information when deciding the optimal bit rate for export. However, I am uncertain if this approach is considered best practice. Are kHz and bit rate entirely unrelated? Is it acceptable to export an audio file at 320 kbps, even when the spectrogram indicates a kHz maximum of 20 or less?

I acknowledge that this is a highly technical inquiry, and I’ve endeavored to articulate my question as clearly as possible. Any insights into this matter would be greatly appreciated!

1 Like

In the context of digital audio, “kbps” and “kHz” refer to different units of measurement; it is important to grasp the differences between them when discussing sound recording, transmission, and reproduction.

The symbol for kilobits per second is “kbps”. It is a bit rate or data transmission rate measurement. It particularly refers to the quantity of data used in a digital audio file per second in the context of audio. The word “kilobit” implies that we are discussing thousands of bits per second. More data is sent per second the higher the kbps. To assess the quality and size of a digital audio file, this measurement is essential. To put it simply, more kbps, or a greater bitrate, usually translates into higher audio quality because more audio data is recorded. But it also means that file sizes will increase.

In comparison to an MP3 file encoded at 128 kbps, one encoded at 320 kbps will have greater sound quality but a larger file size.

However, “kHz” refers to kilohertz, which is a unit of measurement for the frequency that expresses the number of cycles per second. When referring to audio, it typically means a digital audio file’s sampling rate. How frequently audio samples are obtained to build the digital representation depends on the sampling rate. An audio file with a 44.1 kHz sampling rate, for instance, is sampled 44,100 times per second. Accurate audio reproduction can be achieved by capturing a greater range of frequencies using a higher sample rate.

But just like bitrate, greater file sizes are also a result of higher sampling rates. The 44.1 kHz sampling rate of typical CD-quality audio is thought to be adequate for faithfully reproducing the frequency range that is perceptible to the human ear.

In conclusion, although both kbps and kHz are important in the field of digital audio, they gauge distinct things. The bit rate (kbps) of an audio file determines its size and quality by measuring the amount of data consumed per second. On the other hand, kHz measures the audio’s frequency range and how faithfully the frequencies are captured in a digital format. Both have a big impact on digital audio quality, but they have differing effects on sound quality.