Comparison of Audio Time Stretching Algorithms

 

TL;DR Jump to the Hard test and listen to the Original and to the Length 200% column.

The Contenders
1 Tested using Reaper
2 This is an open source algorithm.
The Light Test

Notes:

Original
Algorithm Length 110% (slower) Length 160% (slower) Length 50% (2 times faster)
Amazing
Elastique Efficient
Elastique PRO
Quantum
Radius
Rubberband
SoundTouch
SuperPV
Tachyon
ZTX
The Hard Test
Original
Algorithm Length 130% (slower) Length 200% (slower) Length 320% (slower)
Amazing
(1) (1)
Elastique Efficient
Elastique PRO
Quantum
Radius (2) (2)
Rubberband (3)
SoundTouch
SuperPV
Tachyon
ZTX
(4) (4)

Notes:

The Speed Test

This table shows the time it takes to transform 60 seconds of stereo, 44.1 kHz audio at 110% of the length. The tests were performed on the same reference computer.

Algorithm Time in seconds (smaller means faster)
Amazing    2.6
Elastique Efficient    0.69
Elastique PRO    1.0
Quantum    4.2
Radius   12.0
Rubberband    2.51
SoundTouch    0.92 (high quality) / < 0.25 (fast - sounds similar)
SuperPV    2.8
Tachyon  144.0 (quality 4) / 48.0 (quality 3 - sounds almost the same)
ZTX   16.8 (best) / 2.5 (good - sounds almost the same)
Musical References
[Light Test] John Lennon, "Imagine", Imagine (2010 - Remaster), EMI Records LTD, 2010
[Hard Test] Sia, "Bird Set Free", This Is Acting, RCA Records, 2016