TerraTec Algorithmix Sound Laundy User manual

03.08.01
Manual (English)

2 Algorithmix® Sound Laundry™ TerraTec Edition (English)
Contents
1. Overview..............................................................................................................................3
2. Getting Started ....................................................................................................................4
3. Playback Section ................................................................................................................. 5
4. Processing Section ..............................................................................................................6
5. Descratcher ......................................................................................................................... 7
6. Denoiser..............................................................................................................................8
7. Application Tips...................................................................................................................9
8. Keeping in Touch................................................................................................................11
Fig.1: The Sound Laundry™ TerraTec Edition window.

Algorithmix® Sound Laundry™ TerraTec Edition (English) 3
1. Overview
Introduction
Sound Laundry™ TerraTec Edition is a powerful tool for cleaning up problematic and historic
recordings directly on your PC. It helps you remove or significantly reduce unwanted audio,
maintaining authentic sound with almost no degradation of its original quality.
Sound Laundry™ TerraTec Edition is an ideal enhancement for audio editing and CD
recording programs, especially, if you are in interested in transferring all your treasures from
tape, vinyl or even shellac records to CD using TerraTec PhonoAmp. The Sound Laundry™
TerraTec Edition offers almost full functionality comparing to our Sound Laundry Compact ™.
It was developed especially for the multi-media user who does not want to spend hours
learning complicated processing procedures, as well as the meanings and uses of the never-
ending parameter adjustments needed by other professional software. Both processing
modules, Descratcher and Denoiser require setting up only two parameters for optimization,
usually within a few seconds. You can easily do this during real-time playback. In addition,
you can adjust the volume and the timbre (bass/treble) of the cleaned output signal.
Features:
·real-time operation with 166 MHz MMX Pentium under Windows® 95/98/Me/NT/2000
·high stability because of stand-alone operation
·44.1 kHz / 16 bit ”red book” WAV format accepted
·the world’s fastest off-line processing
·easy, intuitive interface
·remove transient noises like clicks, spikes, static discharge, crackles, pops, surface noise
·reduce constant background noise like hiss, hum, and thyristor buzz
·soften digital distortion and mask drop-outs
·real-time preview while fine-tuning the parameters
·unique difference function for monitoring the noise being removed
·all calculations with up to 80-bit floating-point accuracy
Typical Applications:
·archiving and restoration of historic audio materials
·remastering old recordings to CD: shellac, vinyl, tape
·removing noise from demos recorded onto cassette decks
·cleaning up noisy dialogs or telephone cuts
·reducing noise for AM radio, short-wave radio, and FM broadcast
·removing broadband noise from video tracks

4 Algorithmix® Sound Laundry™ TerraTec Edition (English)
2. Getting Started
Installation
Sound Laundry™ TerraTec Edition is delivered on a CD configured for automatic installation. If
the AutoStarter application does not start automatically, simply double-click autorun.exe (to
be found within the root directory of the CD) and follow the on-screen instructions.
For a quick check of the Sound Laundry™ TerraTec Edition installation, simply click and
select the democlic.wav file for processing. Sound Laundry™ TerraTec Edition supports wave
files according to the red book standard: 16-bit / 44.1 kHz.
Operation
Sound Laundry™ TerraTec Edition features an intuitive interface. Following the steps below
you can get professional-quality results when cleaning up scratchy or noisy recordings in
minutes.
1. Open the File Menu by clicking the [LOAD] button.
2. Chose the WAV file you intended to process.The desired file will be loaded and its
waveform will appear in the waveform window.
3. Start playback with the button. At this point you should be able to hear the sound
and observe the peak-level meter as well as the Analyzer windows showing input signal,
output signal and noise profile. You can stop the playback with the button and
”rewind” to the beginning with the . During the playback it is possible to restart from
any point you like by snapping the cursor in the waveform window and placing it at the
desired position.
4. If your recording is contaminated with strong transient noises like spikes or clicks, set up
the declick fader.
5. If your audio material contains crackles or thyristor buzz, set up the decrackle fader.
6. If you need to remove broadband noise like tape hiss or remaining vinyl surface noise, use
the Denoiser; set up threshold and reduction faders.
7. To compare the original sound with the restored sound, click the box [bypass all].
8. To hear only the ”garbage” being removed, activate our unique [difference] feature.
9. Adjust volume and bass/treble sliders according to your taste.
10. Click [STORE] to store the final processed audio material to a new file. Such files (in 16-bit
format) can be then written to a CD using any recording program capable of burning audio
CDs.
11. How to adjust the parameter of the Descratcher and the Denoiser to gain the best possible
audio quality is described in the sections Descratcher, Denoiser and Application Tips

Algorithmix® Sound Laundry™ TerraTec Edition (English) 5
3. Playback Section
The Playback Section is placed in the lower part of the Sound Laundry™ TerraTec Edition
window. You can load a WAV file for processing, start and stop playback, as well as jump to
the desired position in the WAV file by moving the cursor in the waveform display.
After loading a WAV file, its name and format is shown in the status window below the
Analyzer and its waveform is displayed in yellow in normalized view, i.e., properly squeezed
to the width of the waveform display.
Fig. 2: The Playback Section of Sound Laundry™ TerraTec Edition.
The processed audio material can be stored off-line by opening the file dialog with the
[STORE] button. The sampling frequency of the output file is the same as the input file (44.1
kHz). File format conversion or sampling rate conversion like 96 kHz to 44.1 kHz should be
done by the appropriate high-quality tool in your editing or soundcard software.
List of the buttons and switches in the Playback Section
opens this help file
stops the playback
starts the playback
moves the playback cursor to begin
opens the load file dialog
opens the store file dialog
CPU [ XX % ] shows the computer load, i.e., how much computational Sound
Laundry™ TerraTec Edition is using
difference allows listening to only the noise being removed during processing
bypass all allows listening to the input only bypassing the Descratcher and
Denoiser

6 Algorithmix® Sound Laundry™ TerraTec Edition (English)
4. Processing Section
The Processing Section of the Sound Laundry™ TerraTec Edition consists of four main parts:
Descratcher (left), Denoiser (right), Analyzer (in the middle), as well as Bass/Treble and
Volume controls (below). Two level meter allow you to monitor the final output level while
setting up the volume and bass/treble controls.
Since the CPU requirement of the Sound Laundry™ TerraTec Edition is very low (about 30% on
a 300 MHz PentiumII for a 16 bit, stereo, 44.1kHz .WAV file) you can optimize all the
parameters while listening to the processing in real-time.
Fig. 3: The Processing Section of Sound Laundry™ TerraTec Edition.

Algorithmix® Sound Laundry™ TerraTec Edition (English) 7
5. Descratcher
The Descratcher effectively removes clicks and crackles from old vinyl or shellac records, and
from audio files contaminated during recording due to switching, digital cross-talk, or thyristor
buzz.
The descratching algorithm consists of two main parts: the declicking filter and the
decrackling filter. While the declicking filter is normally used to remove heavy clicks from old
vinyl records or switching noise arising from analogue or digital audio equipment, the
decrackling filter removes any remaining, mostly small but dense clicks called crackles.
The higher the declick parameter is set, the more clicks are removed. At a setting of zero,
virtually all clicks pass through the filter. For the declicking of typically polluted vinyl records
transferred to the digital domain, a declick value of approximately 50 works well in the most
cases.
Fig.4: Typical click in the signal taken from a vinyl record (left) and restored signal (right).
The higher the decrackle parameter is set, the more crackles are removed from the original
signal. The extreme setting, close to 100, results in a smoothing of the input signal. In general,
this parameter can safely be set to 80 without any audible artefacts. In some cases, even an
extreme setting up to 100 can still improve the quality of processed audio material.
In order to minimize the occurrence of artefacts in the descratching process, the final setting
of the declick and decrackle parameters should be performed by critically listening to different
parts of the audio file to be cleaned up. We highly recommend using the difference feature of
the Playback Section, allowing optimal parameter set-up in a very intuitive way. You can
switch between the original input signal and the input/output difference, i.e., the part of
signal removed by the descratching algorithms. This difference signal normally should not
contain parts of the original signal you want to preserve. For further remarks on how to
optimally set up the decklick and decrackle parameter, see Application Tips.
Please note that the difference feature works for both Descratcher and Denoiser
simultaneously. Therefore if you want to concentrate only on Descratcher performance, leave
both Denoiser faders (threshold and reduction) at zero.

8 Algorithmix® Sound Laundry™ TerraTec Edition (English)
6. Denoiser
The Denoiser belongs to the so-called single-ended noise reduction systems. This means it
does not need any special coding procedure before recording, like in the famous tape noise
reduction system from DOLBY™ Lab. It is a tool that efficiently removes any kind of broad-
band noise from pre-recorded audio tracks. The Algorithmix® Denoiser is a weapon against
tape hiss, noise from telephone-call cuts, and residual noise from old records after processing
with the Descratcher.
In a single-ended noise reduction systems, the user decides which noise characteristics have
to be applied to the denoising process. A typical broadband noise profile, optimized for
surface noise of vinyl records as well as tape hiss, is used in this version of the Denoiser.
The noise reduction process in the Denoiser is controlled by just two parameters, allowing an
easy search for optimal results, depending on the given input signal.
The frequency spectrum of the input signal (red), the noise profile (white) applied to the
processed audio material, as well as the spectrum of the output signal after processing
(green) can be followed in the Analyzer window.
The noise profile (white) marks the threshold border, above which no noise reduction is
applied. The threshold parameter moves this noise profile up and down and can be used to
set up the profile just above the background noise level. For a given threshold, the second
parameter, called reduction, decides the amount of removed noise below the chosen noise
profile.
A good starting value for threshold is to set the noise profile just above the background noise
level (approx. 10 dB). A subsequent increase of the reduction parameter should significantly
reduce the background noise. If noticeable artifacts in the form of so-called singing or robot-
like sounds appear (time aliasing phenomenon), decreasing the reduction parameter and
increasing the threshold level (up to about 30 dB above the background noise) usually helps.

Algorithmix® Sound Laundry™ TerraTec Edition (English) 9
7. Application Tips
The Descratcher and the Denoiser are easy-to-use audio restoration tools based on extremely
efficient signal processing algorithms. In most cases you will automatically achieve good
results. To get the maximum, especially when working with heavily damaged audio material,
there are some practical rules:
1. Use a stereo record player if you restore old mono vinyl or shellac records and process
both channels individually before merging again to mono. This improves the signal-to-
noise ratio by at least 3dB (actually a factor of two) when compared to the descratching
procedure applied to pure mono files.
2. transfer recordings to be restored directly to .WAV file without using any processing device
like a limiter or compressor prior to the descratching procedure.
3. If the audio material to be restored contains very strong clicks, you may allow some
clipping while transferring to the digital domain. We recommend you make a few versions
recorded with different input gain and compare the results after the descratching process.
4. Do not exaggerate with the declick and decrackle parameters to avoid artefacts. When
working on heavily disturbed material, use a good acoustical compromise between the
level of remaining disturbances and artefacts introduced to the output signal. Be
indulgent if you have hopelessly damaged material; nobody can restore original data from
nothing.
5. Very strong changing noise level and noise characteristic may be problematic. In such
cases professional mastering engineers try to cut the original piece in parts and treat them
individually with different de-noising parameters. Later the denoised pieces are joined
together.
6. Do not exaggerate the parameters threshold and reduction to avoid artefacts in the form of
singing or robot-like sounds (time aliasing). Begin with a moderate adjustment by setting
the noise profile to just above the background noise level (approx. 10 dB) and gradually
increasing the reduction parameter. Finally try to recursively find the best relation between
these two parameters.
7. If you are working on heavily disturbed material, find a good acoustical compromise
between the level of remaining noise and artefacts introduced to the output signal. Be
indulgent if you have hopelessly noisy material. Nobody can restore the original signal
without having enough original information.
8. It helps sometimes to apply the denoising process two or more times consecutively with a
moderate parameter setting rather than one pass with an extreme setup.
9. A recommended tool that significantly helps to adjust the Denoiser parameters is the
Analyzer. It allows for following the denoising process, especially the influence of the
noise profile and parameters.

10 Algorithmix® Sound Laundry™ TerraTec Edition (English)
10. If you feel that the output signal is not enough loud increase volume watching the left and
right level meters. If you realize that the most highest red LEDs shine the volume is already
too high; you have reached so called clipping level which may results in audible
distortions.
11. It is possible to smoothly increase (+) or decrease (-) the amount of high and/or low
frequencies in the final output signal according to your sound timbre preferences using
bass and treble sliders. It is possible that the raising of the bass or treble controls
increases output signal volume up to the clipping level. In such case you need to lower the
volume slider until clipping disappears (the most highest red LEDs does not shine
anymore).
12. Low-cost sound cards used for A-D/D-A conversion may themselves introduce severe
artefacts and noise to an audio signal. For professional applications, use high-quality
audio cards like the TerraTec EWX 24/96.
13. If you record and process your audio files using 48 kHz or even 96 kHz sampling
frequency, you have to be sure to use a high-quality conversion tool if going down to the
CD sampling rate frequency, 44.1 kHz.
14. For the best results, use your own ears in combination with the difference feature of
Playback Section. Switch between the original input signal and the input/output
difference, i.e., the part of the signal taken out by the descratching and denoising
algorithms. This difference signal normally should not contain any parts of the original
signal you want to preserve.
Important Remark:
The Sound Laundry™ TerraTec Edition is a very fast and very effective tool. You will be
amazed by how dramatically the audio quality of old records and problematic audio files can
be improved. But please do not expect miracles if you process material with long gaps or
jumps. The information theory says that once the information is lost and there is not enough
redundancy in the remaining material, the restoration process for the original material is
impossible. In such hopeless cases, experienced mastering engineers try to transfer similar
recording parts into gaps using very precise audio editors. The same is if you process material
containing so much noise that the original signal is no longer distinguishable. Also here the
information theory says that once the information is sunk in noise (very bad signal-to-noise
ratio) and there is not enough information about the properties of the original signal, or even
worse, the original signal is in addition non-linearly distorted, the denoising process can
deliver only limited-quality results.

Algorithmix® Sound Laundry™ TerraTec Edition (English) 11
8. Keeping in Touch
For further information concerning enhancements, updates and new Algorithmixâproducts,
visit us on the Internet at:
http:// www.algorithmix.com
or send e-mail:
to [email protected]
if you need any information about installation and performance of this product,
or to [email protected]
if you have general suggestions and questions concerning our product line.
Algorithmix® and Sound Laundry™ are trademarks of Algorithmix GmbH. All other product
and company names mentioned above are ™ or ® trademarks of their respective owners.
The information in this document is subject to change without notice. No part of this
document may be copied , reproduced, transmitted, or recorded, without prior written
permission of Algorithmix GmbH.
Copyright © 2000 Algorithmix GmbH. All rights reserved.

12 Algorithmix® Sound Laundry™ TerraTec Edition (English)