SMP to SPH Converter

Prepare Turtle Beach SMP audio for SPHERE speech research

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Research Standard

Convert SMP samples to SPH — the SPHERE format trusted by speech research and linguistics communities.

Legacy to Corpus

Transform vintage SMP samples into research-ready SPH files for speech recognition and phonetics work.

Secure Handling

Your SMP files are erased after conversion. SPH outputs deleted from servers within 24 hours.

How to convert SMP 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

SMP is the native file format of SampleVision, a sample editing application developed by Turtle Beach Systems around 1990. SampleVision was among the first PC-based visual sample editors, letting musicians view waveforms on screen and perform cut, copy, paste, and loop-point editing — capabilities previously limited to expensive dedicated hardware samplers. The SMP format stores 16-bit mono PCM audio along with sampling-specific metadata: loop start and end points, sustain loops, release loops, and MIDI root note assignments. This made SMP files directly useful for creating and exchanging patches between hardware samplers via MIDI Sample Dump Standard (SDS) transfers, which SampleVision automated through its interface. A primary advantage was bridging the PC world with professional sampling hardware from Akai, E-mu, Ensoniq, and Roland — devices that had tiny screens and minimal editing tools. The format also supported common sample rates (22050, 44100 Hz) and brief text descriptions alongside audio data. Though Turtle Beach pivoted to gaming peripherals and SampleVision was discontinued, SMP files persist in vintage sample library archives and can be converted using SoX.
Initial release: 1990
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 SMP to SPH?

SPH (SPHERE) is standard for speech corpora in research. Converting SMP to SPH prepares legacy samples for linguistic analysis.

What opens SPH files?

NIST tools, HTK, Kaldi, and linguistic research frameworks work with SPHERE format audio data.

Does SPH include metadata?

Yes — SPHERE format includes rich text headers for metadata like speaker info and recording conditions.

Can I convert multiple SMP files at once?

Upload a batch of SMP samples and convert them all to SPH simultaneously — efficient for processing entire libraries.

Is the conversion secure?

SMP uploads are deleted after processing, and SPH outputs are removed from our servers within 24 hours.