Prices. Choose optimal >
Order >

Extract ISO to DSF PCM. Clicks Issues. Part 1

Clicks into DSF or PCM (FLAC, WAV, AIFF, etc.) files extracted from ISO (1-bit audio) is fairly common occurrence.

«How extract ISO without clicks?» is one of most popular questions associated with conversion ISO 1-bit audio to music files.

Extract ISO to DSF PCM. Click Issues

Main issue here is plenty of different click types.

There is no general recommendation: how to fix any kind of these clicks.

Here we consider several possible types and try recommend action(s) for fixing each one.

You can try clicks either experimentally or after analysis of converted audio file content.



Let me begin from click reasons currently known me:

1. DC bias across a album >

2. Non-zero border level in albums with live concerts, operas, etc. >

3. Clicks placed into pauses between tracks >

4. Clicks inside audio stuff far enough from begin and end of file >

May be in the future will discovered new reasons. ISO surprise me not once.

Whether or not we hear clicks, depend on hardware software playback processing, volume level of amplifier.

1. DC bias across a album

ISO to DSF PCM extraction clicks - DC offset

a) Bit perfect extraction

Audio content of ISO can be extracted to DSF as is (without changes, bit-perfect extraction).

There no resampling and other processing.

If these files will be monitored at audio player with gapless playback ability, we won't hear clicks.

If the tracks are played back separately or other order than into the album:
Track 1 - probably click at end,
Track 2 - probably clicks at begin and end,
Track 3 - probably click at begin.

Click level depend on sample level at border of track.
Also click level depend on difference of sample levels at common border of next tracks.

For ability random order playback of the album’s tracks, recommended use SmoothDC processing.

SmoothDC click suppressing at begin and end of a audio tracks

Smooth DC PCM DSF - AuI ConverteR 48x44

Smooth DC is fast fade in/out (gain control) at begin/end of a audio track. Gain changing curve has special form that allow approach track from full volume to zero and vice versa smoothly.

Two tracks, processed by SmoothDC have common value at border - zero.

So there is no level "stair" between tracks, that can cause click.

Short time of the fade in/out is designed to minimisation of impact to track.

Special form of changing gain during time is designed for more smooth transient at track border(s).


b) Resampling of extracted DSF or extracting ISO to PCM

Tradition resampling re-initialised at begin of each converted track. Conversion ISO to PCM may be considered here as resampling too.

It is good for batch audio conversion of mixed unrelated tracks.

But for album type with general DC bias re-initialising will generate transient processes (noise)  at begin and end of the track.

At common spectrum of merged next tracks we can see it as splash (line at track border).

Gapless Conversion Audio Files


For minimal border changes recommended use gapless conversion, where all album tracks processed sequentially in album order.

Proper playback of resampled files should be gapless. Otherwise clicks can appear probably.


Yuri Korzunov,
Audiophile Inventory developer


Read part 2 >

AuI ConverteR 48x44 RSS Audiophile Inventory on Facebook Audiophile Inventory on Google+ Audiophile Inventory on LinkedIn

Audiophile converter
 CD ripper
DSF/FLAC metatag editor
AuI ConverteR 48x44


Import/Export Metadata during Conversion Audio

Read metadata: DSF, WAV, FLAC, AIFF*, mp3

Write metadata: DSF, WAV, FLAC, AIFF*


Metadata Editing



Metadata and CD ripping

Search and export text metadata from free Internet database.

Assigning album artwork before conversion.


Metadata and ISO (1-bit audio) extraction

Extraction text metadata from ISO.

Released new studio audio converter AuI ConverteR 48x44 v. 6.4 CD ripper, ISO, DFF, DSF, WAV, FLAC, AIFF, ALAC. Improved ISO extraction target directory management.

Audio Basis - Educational program

DSD converter is software for conversion DSD audio files to other formats and back. DSD audio files have extensions DSF, DFF, ISO. As target or source formats PCM multibit formats (WAV, FLAC, AIFF, mp3, etc. files and CD-audio disks) can be used. Also such converter can resample DSD files. Below will described how to work the converter.