What professionals say about Ximpa

"OK, this is truly spectacular! You have achieved probably 98% of the quality of the best SRC algorithms I have tested, and you manage to do it in a fraction of the time. One of the closest in terms of quality and general attributes of result files takes 10 seconds to process a one-minute 96kHz file to 44.1kHz (extrapolate as desired). Ximpa (at its highest setting) only takes 4 seconds! So you perform 66% faster while accomplishing 98% of the quality? I wish I could get close to those numbers with other time-consuming dsp chores. It would revolutionize the throughput of my studio!"

Stephen V. Smith,
Soundsmiths Mastering, Inc.

Sample Rate Conversion

Sample rate conversion (SRC) is the process of changing the sampling rate of a data stream from a specific sampling rate (e.g. the input/output hardware rate) to another sampling rate (e.g. the application rate). With the conversion of communication and software markets, SRC is becoming a necessary component in many of today's applications including Digital Mixing Consoles and Digital Audio Workstations, CD-R, DAT, DCC and MD Recorders, Multitrack Digital Audio and Video Tape Recorders, Studio to Transmitter Links, Digital Audio Signal Routers/Switches, Digital Audio Broadcast Equipment, Digital Tape Recorder Varispeed Applications, and Computer Communication and Multimedia Systems. In most of those applications, a very high quality sample rate converter is required. Most high quality SRCs currently available on the market employ a digital filter that provides the required quality by up-sampling the data to a very high sampling rate followed by down-sampling to the required output sampling rate. The disadvantage of this technique is the huge amount of computation required to implement such a digital filter. DSP Algorithms Ximpa Sample Rate Converter is designed from scratch to provide very high quality and at the same time requires low computation power.

Product Features

Ximpa Sample Rate Converter consists of two parts; a proprietary digital filter design module and the corresponding filter synthesis module. The former designs the coefficients of high quality digital filters, and the latter filters blocks of samples through the previously designed filters. Ximpa efficiently supports multi-channel streams, and is suitable for real-time as well as off-line sample rate conversion. The default digital filter has the following characteristics:

  • Stopband attenuation = 150 dB.
  • Passband ripple = 0 dB.
  • Passband frequency range = 0.9875% of the output bandwidth.
  • Transition band = 0.0956% of the output bandwidth.

The impulse response and frequency response of a Ximpa digital filter designed to convert the sampling rate from 48kHz to 32kHz is shown in the figure below. Click on the image for a better view.

ximpa filter


Ximpa Sample Rate Converter is available in two forms.

  1. A Windows application to convert the sampling rate of audio files from any sampling rate to any other sampling rate.
  2. A Software Developing Kit (SDK) that enables developers of desktop, embedded systems, and DSP applications to integrate Ximpa into their applications for real-time sampling rate conversion. The SDK is directly available for several platforms.

Audio Samples

Input: Classical music input at 44.1kHz, stereo.
Output: Classical music output at 48kHz, stereo.

Input: Speech input at 11.05kHz, mono.
Output: Speech output at 16kHz, mono.

Download Ximpa Sample Rate Converter Demo

To closely examine the performance of the Ximpa SRC software using your own audio samples, download the Ximpa demo. This Windows application will allow you to convert the sampling rate of any audio file and listen to the original and resulting files from within the application. Although the Ximpa software can convert from any sampling rate to any other sampling rate, the demo output sampling rate is limited to those rates commonly used with modern PC sound cards. The demo will process the first 30 second of the input file.

Ordering and More Information

To order Ximpa File Processing application for Windows or Ximpa SDK for Windows click here. Please contact us for availability on other platforms and more information on this product .