join audio files different formats online
Joining a 44.1kHz MP3 with a 48kHz WAV, or a mono narration track with a stereo one, needs no manual conversion beforehand: the tool decodes each file to separate samples and reconciles the differences on its own. The output always uses the HIGHEST of the input sample rates and the WIDEST channel count, never the rate or channel count of the first loaded file, and every conversion applied is listed in a report before export.
The narration gets upsampled and upmixed at the same time, but keeps its 3-second duration and original pitch.
The join itself preserves the 96kHz, only the final MP3 encoding step applies the format's 48kHz ceiling.
With no rate difference among the three, only the channel count needs adjusting, and the report points to exactly which file changed.
Crossfade is a transition technique where the end of one track fades out while the beginning of the next fades in, creating a smooth overlap. It is ideal for continuous music mixes, soundtracks, or podcasts where abrupt cuts would sound jarring.
Yes. Each file is decoded to samples independently, and the lower-rate track is resampled up with a Blackman-windowed sinc filter, to match the highest rate present among the loaded files. No file loses bandwidth because of the join, since the conversion always goes up, never down.
Because the MP3 format (MPEG-1/2/2.5 Layer III) only supports rates between 8000Hz and 48000Hz, and 96kHz sits above that ceiling. The tool automatically snaps it to 48kHz before encoding, instead of simply failing or producing a file that plays back wrong.
No. The mono file gets duplicated across every output channel before entering the join, so it plays equally out of both speakers, with the right channel an exact copy of the left, not silence on one side.
Your files are processed locally in the browser. No data is sent to any server.