SPX to AVR Converter

Decode Speex into Audio Visual Research format online

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Research Audio Format

Decode Speex recordings into AVR — the Audio Visual Research format used on Atari ST and in specialized audio labs.

Server-Side Processing

All encoding runs on our cloud infrastructure — no Atari emulators or research tools needed on your computer.

Private and Secure

SPX uploads are erased immediately. AVR outputs are removed from servers within 24 hours.

How to convert SPX to AVR

1

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

2

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

3

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

About formats

Speex is an open-source audio codec purpose-built for speech compression, developed by Jean-Marc Valin under the Xiph.Org Foundation. First released in October 2002, it targets voice-over-IP, conferencing, and any scenario where spoken word needs to travel efficiently over a network. SPX files wrap Speex-encoded audio inside an Ogg container, pairing the codec's speech optimization with Ogg's streaming capabilities. Three sampling rates are supported — narrowband at 8 kHz, wideband at 16 kHz, and ultra-wideband at 32 kHz — along with variable bitrate encoding that adapts in real time to speech complexity. A standout advantage is its patent-free, BSD-licensed nature, which allowed developers to embed it freely in both commercial and open-source products. Speex also bundles acoustic echo cancellation, noise suppression, and automatic gain control, features that rival codecs typically delegate to external libraries. Although its creators officially recommend Opus as a successor since 2012, Speex remains deployed in legacy VoIP systems, archived recordings, and embedded devices where its lightweight decoder footprint is still valued.
Initial release: October 15, 2002
AVR (Audio Visual Research) is an audio format that originated on the Apple Macintosh around 1989, created by the Audio Visual Research company for their editing and synthesis tools. It stores raw audio samples preceded by a fixed-length header containing sample rate, bit depth (8 or 16 bits), channel configuration, and loop point markers. Unlike complex container formats, AVR uses a flat binary structure with no compression, preserving the full waveform quality at the expense of larger files. The format served professional Macintosh audio workstations during the late 1980s and early 1990s, when the Mac platform dominated creative computing. One advantage is uncompressed storage guaranteeing zero artifacts and perfect signal integrity through editing operations. Native loop markers represent another feature, letting sound designers define seamless repetition points within the file — ahead of its time for sample-based music production. Tools like SoX maintain AVR support, ensuring archivists can access and convert these legacy recordings. While eclipsed by WAV and AIFF, AVR remains a notable piece of early digital audio history.
Initial release: 1989

Frequently Asked Questions

Why convert SPX to AVR?

AVR was used on Atari ST and in audio research environments. Converting from SPX enables use with these specialized tools.

What is the AVR format?

Audio Visual Research format was developed for the Atari ST platform, storing simple PCM audio with a compact header.

What opens AVR files?

SOX, Audacity (via import), and Atari ST emulators can handle AVR files.

Is AVR compressed?

No — AVR stores uncompressed PCM audio, so files will be larger than compressed SPX sources.

Is the conversion free?

Yes — free on convertio.tools for standard usage.