W64 to SPH Converter

Easily convert W64 audio into SPH format online

Drop files here. 1 GB maximum file size or Sign Up
to
Facebook Amazon Microsoft Tesla Nestle Walmart L'Oreal

Batch Processing

Upload multiple W64 files at once and convert them all to SPH simultaneously. No need to repeat the process file by file.

Quality Preserved

The W64 to SPH conversion maintains maximum audio fidelity. Your recordings come through clean, without unnecessary artifacts.

Browser-Based Tool

No software to install — convert W64 to SPH directly in Chrome, Firefox, Safari, or Edge. Open the page and start converting.

How to convert W64 to SPH

1

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

2

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

3

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

About formats

W64 (Wave64) is a 64-bit audio container originally designed by Sonic Foundry — creators of Sound Forge — and later maintained by Sony after acquiring Sonic Foundry's desktop software division in 2003. The format directly addresses the 4 GB file-size ceiling imposed by Microsoft's 32-bit RIFF/WAV specification, a limitation that becomes problematic during long recording sessions, multi-channel captures, or high-sample-rate productions. W64 achieves this by extending chunk identifiers and size fields to 64 bits, using GUIDs instead of four-character codes. This structural change permits files to reach sizes measured in exabytes, effectively removing any practical storage constraint. The format supports arbitrary sample rates, bit depths, and channel configurations, making it well suited for film scoring, live concert recording, and scientific data acquisition. Sound Forge, Audacity, and other professional digital audio workstations provide native W64 support for seamless import and export. For engineers and producers who routinely work with long-form, high-fidelity material, W64 offers the reliability and simplicity of WAV without the frustrating size restriction.
Developer: Sonic Foundry
Initial release: 2001
SPH is the file extension for audio stored in the NIST SPHERE (SPeech HEader REsources) format, a standard created by the U.S. National Institute of Standards and Technology around 1990. Built for speech research, SPH files carry a 1024-byte ASCII header packed with metadata — database identifiers, channel counts, sample rates, byte ordering, and compression type — making every recording self-describing. The underlying audio is typically 16-bit linear PCM sampled at 16 kHz, though other configurations are permitted. Researchers at NIST, DARPA, and universities worldwide rely on SPH for distributing speech corpora such as TIMIT, Switchboard, and the LDC collections that underpin modern automatic speech recognition systems. A key advantage is that the human-readable header lets scripts parse recording metadata without binary decoding. The format's strict standardization also eliminates ambiguity when sharing datasets across institutions and platforms. Because SPH files store uncompressed PCM, they preserve full audio fidelity — critical when training acoustic models where even small artifacts can skew results.
Initial release: 1990

Frequently Asked Questions

Why convert W64 to SPH?

The Wave64 format is overkill for most listeners. SPH delivers your audio in a format anyone can open instantly.

How do I open a SPH recording?

Open SPH with NIST SPHERE tools, SoX, speech processing software. These applications provide full playback and editing support for the format.

Will I lose audio quality in the conversion?

Quality depends on the codec. If SPH uses lossy encoding, minor data loss occurs. Lossless targets preserve the original W64 audio faithfully.

How many W64 files can I convert in one go?

Upload as many W64 files as you need and convert them to SPH simultaneously. The batch feature handles multiple files efficiently.

Are my W64 uploads kept private?

Yes. Uploaded W64 files are deleted right after conversion, and the SPH output is removed from our servers within 24 hours automatically.