The source limits the output
When a YouTube video is uploaded, its audio is compressed to save bandwidth, typically topping out around 128 kbps to 160 kbps for standard streams. When you use a converter to "download in 320 kbps," you are placing a 128 kbps stream into a 320 kbps container. This process, known as upscaling, adds empty data padding and increases the file size without adding any lost acoustic detail.
Visualizing the difference
If you examine the frequencies using a spectrogram, genuine 320 kbps audio shows frequencies reaching up to 20 kHz and beyond. However, upscaled audio from YouTube exhibits a hard cut-off around 15 kHz to 16 kHz. The missing frequencies were permanently removed during YouTube's initial compression; no converter can synthetically recreate them.
Generation loss
Every time a lossy audio format like MP3 or AAC is re-encoded, it suffers from generation loss. Downloading a YouTube video and converting it to MP3 involves decoding the source and re-encoding it. Selecting an excessively high bitrate doesn't stop generation loss—it only masks it by making the resulting artifact-heavy file larger.
The ideal setting
For the best balance of file size and quality, matching the source bitrate is optimal. Selecting 192 kbps is generally recommended for YouTube conversions as it provides enough overhead to avoid compounding compression artifacts without creating unnecessarily large files.
Frequently Asked Questions
No. YouTube standard streams deliver audio at approximately 128-160 kbps AAC or Opus. YouTube Music Premium offers 256 kbps.
It won't sound significantly worse, but it will take up more than twice the storage space with zero audible benefit.