How to upsample audio

Last updated on June 28, 2024 by , Posted to edit audio

upsample audio

Higher sampling rates do not always provide benefits in all situations. The size of the audio file is directly proportional to this parameter, while not everyone will notice the difference in sound quality. However, there are cases where you need to use a high sample rate to ensure compatibility with hardware, software, or common standards.

Here are three commonly used sample rates that audio can be converted to:

  • 44.1 kHz: Meets the international CD audio standard adopted half a century ago.
  • 48 kHz: Is the standard for video and film dubbing.
  • 96 kHz: High-resolution audio used in recording studio masters.

However, it is important to remember that any sample rate conversion will result in a loss of audio quality. The full benefits of a high sampling rate are only realized if it is selected during recording creation. But here we mainly focused on how to resample finished audio files saved in MP3, WAV, FLAC, OGG, etc. format.

1 When is upsampling really needed?

The most common reason for upsampling that I currently encounter is when working with neural networks. Most speech enhancement and cleaning models are trained at a fixed sampling frequency - 48000 or 44100 Hz. At the same time, speech recording does not require a wide frequency range, which allows digital voice recorders to save storage space. In this case, upsampling is essential.

The second most common reason is working through low latency ASIO interfaces. Having many advantages when working with DAWs, they nevertheless have limitations in supported sampling rates. For example, my May 44 ESI has a lower limit of 32000Hz. When playing audio recordings with lower sampling rates, there is no way to do without upsampling.

Previously, I would have started by mentioning Audio CD or DVD as the main reason for upsampling, but now they are almost out of use. So that's one less reason. Modern audio codecs do not have this problem, and if they do, there is always an alternative.

2 How to upsample audio in Windows

Audio Converter Plus offers an easy way to convert audio to any possible format from 8 kHz to 96 kHz. It is worth mentioning that the capabilities of the resampler are not limited to this range, so the input parameters may go beyond it. For example, when converting DSD streams, the input frequency can be 384 kHz.

In my opinion, there is no need to upsample to higher frequencies, such as 192kHz, which are of interest only to audiophiles. Moreover, audiophiles themselves never accept sound that has been oversampled.

Since the sampling rate is changing, it's a good idea to make all the necessary changes in one pass. Changing the number of channels or normalizing the volume can be a free bonus.

Download this simple yet powerful audio upsampling converter for free:

sampling rate converter

With default settings, the converter will try to maintain the sampling rate as long as possible. Automatic conversion is activated in rare cases, for example for the Opus format, which does not support the most common sampling rate of 44100Hz.

In most cases, you will need to set all parameters manually. But don't worry, it's very easy to do.

Step 1: Import the audio file
Launch the converter and import audio files into the program using the "Add files" or "Add folders" buttons. Finally, you can simply drag and drop audio files onto the converter icon on your desktop.

Step 2: Select Audio Format
At the bottom of the main window, select the desired format from the list. Please note that the settings for each format are set independently and will be used for all imported files.

upsampling options

Step 3: Adjust the sample rate
Click the Encoder Options button to the right of the format list. Sampling frequency comes first and contains a list of frequencies available for the selected format. You can change the remaining parameters at your discretion. You can simply leave them in the "Same as original" position. Don't forget to click OK to confirm the changes.

Higher sample rates are not available for all audio formats. For example, MP3 supports a maximum of 48 kHz, and the legacy GSM codec is limited to 8 kHz. Typically, the highest sample rates are available for lossless codecs.

Step 4: Run the conversion
When everything is ready, set a new output folder and click "Convert" to start the conversion.

3 Useful tips

  1. Avoid resampling whenever possible. It does not improve sound quality in any way, but introduces its own distortions associated with aliasing and dithering.
  2. If you need to resample, use integer multiples because they are computationally simpler and more transparent. The worst option is to convert between 44100 and 48000Hz.
  3. All other things being equal, upsampling is more transparent than downsampling. With downsampling, you permanently lose individual samples, and with upsampling, you add new intermediate ones.
  4. Keep in mind that the majority of portable device's DACs are already operating natively at 48000Hz, so it's best to feed them at 48kHz.

4 Let's sum it up

With Audio Converter Plus, anyone can perform fast sample rate conversion on Windows. Additionally, this tool includes many other practical functions for processing all types of audio files, such as transcoding, normalization, metadata transfer, audio size reduction, etc. Get effective universal tool right now!

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