SOU to HCOM Converter

Turn SOU audio into HCOM — no software installation needed

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Rapid Conversion

Most SOU to HCOM conversions complete in seconds. The cloud-based engine processes recordings rapidly regardless of length.

Broader Reach

SOU is a niche legacy format with minimal support. Converting to HCOM brings your audio into a format recognized by SoX and many other tools.

Batch Processing

Upload multiple SOU recordings at once and convert them all to HCOM simultaneously — no need to repeat the process individually.

How to convert SOU to HCOM

1

Select files from Computer, Google Drive, Dropbox, URL or by dragging it on the page.

2

Choose hcom or any other format you need as a result (more than 200 formats supported)

3

Let the file convert and you can download your hcom file right afterwards

About formats

SOU is a raw audio format designation that functions as an alias for unsigned 8-bit PCM data (u8) in the SoX audio processing framework. Files with the .sou extension contain headerless, uncompressed audio samples stored as unsigned 8-bit integers — each byte represents a single amplitude value from 0 to 255, with 128 as the silence midpoint. Because there is no header, playback parameters such as sample rate and channel count must be specified externally. The default assumption is typically mono at 8000 Hz, though the data can represent any rate the recording hardware supported. The u8 encoding that SOU aliases is one of the simplest possible digital audio representations, predating structured audio containers like WAV and AIFF. Raw unsigned PCM was commonly produced by early sound cards and digitizers in the late 1980s and early 1990s, when storage constraints and limited processing power made headerless formats a practical choice. One advantage is absolute simplicity: SOU files can be read by any program capable of basic file I/O, with no parsing of container structures or metadata decoding required — useful for embedded systems, hardware diagnostics, and educational contexts where audio fundamentals are being explored. The format's minimal overhead also means that conversion to any modern container is lossless and instantaneous, since the raw PCM samples can be wrapped in a WAV or AIFF header without any transcoding.
Developer: SoX Contributors
Initial release: 1991
HCOM is a Huffman-coded audio format from the early Macintosh era, designed to shrink digitized sound for distribution on floppy disks and bulletin board systems when storage was precious and modems were slow. The encoder takes 8-bit unsigned PCM input, computes a frequency table of sample-delta values, and builds an optimal Huffman tree that replaces common deltas with short bit sequences. Compression ratios of 2:1 or better were typical for speech recordings, a meaningful saving when a 3.5-inch floppy held only 800 KB. Files were distributed as Macintosh resource forks and played through utilities like SoundApp and the BinHex ecosystem that defined Mac software exchange in the late 1980s. The format supported sample rates up to 22.255 kHz, matching the output capabilities of original Macintosh sound hardware. Tools such as SoX retain HCOM decoding support, ensuring that archived recordings remain accessible decades later. HCOM holds three practical advantages for preservation work: lossless compression that recovers the original samples exactly, a self-contained Huffman table embedded in each file for dependency-free decoding, and historical prevalence across thousands of vintage Mac sound archives.
Developer: Apple Computer
Initial release: 1985

Frequently Asked Questions

Why convert SOU to HCOM?

SOU is a legacy raw audio format without any container structure. Converting to HCOM gives you classic Macintosh audio compression.

How do I open a HCOM audio?

You can open HCOM with SoX, vintage Macintosh software, and retro computing tools.

Does SOU to HCOM conversion affect quality?

Since SOU is already a low-quality telephony format, converting to HCOM typically improves accessibility without meaningful further loss.

Can I convert SOU to HCOM on any device?

Yes — the converter runs entirely in your browser, so it works on Windows, macOS, Linux, and mobile devices alike.

Can I convert multiple SOU recordings at once?

Yes — upload several SOU recordings simultaneously and they will all be converted to HCOM in parallel, saving you time.

Does SOU to HCOM conversion cost anything?

Standard conversions are available at no cost. Paid plans unlock higher limits and faster processing for heavy usage.