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<spanid=toc-menutitle="Table of Contents"><iclass="fas fa-list-alt fa-fw"></i></span><olclass=linksitemscopeitemtype=http://schema.org/BreadcrumbList><metaitemprop=itemListOrdercontent="Descending"><liitemscopeitemtype=https://schema.org/ListItemitemprop=itemListElement><metaitemprop=positioncontent="3"><aitemprop=itemhref=/ardour-tutorial/en/><spanitemprop=name>Home</span></a> ></li><liitemscopeitemtype=https://schema.org/ListItemitemprop=itemListElement><metaitemprop=positioncontent="2"><aitemprop=itemhref=/ardour-tutorial/en/introduction/><spanitemprop=name>Introduction</span></a> ></li><liitemscopeitemtype=https://schema.org/ListItemitemprop=itemListElement><metaitemprop=positioncontent="1"><aitemprop=itemhref=/ardour-tutorial/en/introduction/what-is-digital-audio/aria-disabled=true><spanitemprop=name>What is digital audio?</span></a></li></ol></div><divclass="default-animation progress"><divclass=wrapper><navid=TableOfContents><ul><li><ahref=#frequency-and-gain>Frequency and Gain</a></li><li><ahref=#peaks-and-clipping>Peaks and Clipping</a></li><li><ahref=#sample-rate-and-bit-depth>Sample Rate and Bit Depth</a></li><li><ahref=#continuing>Continuing</a></li></ul></nav></div></div></div></nav><mainid=body-innerclass=highlightable><divclass=flex-block-wrapper><divid=head-tags></div><article><h1>What is digital audio?</h1><p><strong>Ardour</strong> is a digital audio workstation (DAW). Beforing using it to
cause its membrane to vibrate. The microphone turns these acoustic
vibrations into an electrical current. If you plug this microphone into a
computer’s sound card and start recording, the sound card makes thousands
of measurements of this electric current per second and records them as
numbers. The number of <em>samples</em> (i.e. measurements) made per second is
called the <em>sample rate</em>, and the number of possible values each sample can
have is called the <em>bit depth</em>. The combination of sample rate and bit
depth indicates how closely the digital signal can reproduce the sound it
has recorded.</p><h2id=peaks-and-clipping>Peaks and Clipping</h2><p>When Ardour displays the samples which have been recorded, they appear as
the <em>waveform</em> we see below. The center horizontal line indicates the
membrane of the speaker at rest, and the <em>peaks</em> of the waveform indicate
the maximum <em>amplitude</em>.</p><figure><imgsrc=en/Ardour4_Digital_Audio_Waveform.pngalt=Waveform></figure><p>If we take a waveform and increase its amplitude a lot, some of the peaks
may now fall outside the range that the computer can represent digitally.
The computer’s inability to represent peaks outside the range of amplitude
is called <em>clipping</em>, which results in a permanent loss of digital
information, as well as a change in the sound quality which is recognizable
as <em>distortion</em>. Ardour marks clipped peaks with the color red, as can be
seen in the image below.</p><figure><imgsrc=en/Ardour4_Digital_Audio_Clipping2.pngalt=Clipping></figure><p>In the image above, one can also see the <em>mixer strip</em> on the far left,
number indicates clipping has occurred.</p><divclass="box notices tip"><divclass=box-label><iclass="fas fa-lightbulb fa-fw"></i> Tip</div><divclass=box-content><p>Clipping often can happen at the time of recording if you set your
microphone levels too high.</p></div></div><p>The range of decibels between the region’s maximum peak and the clipping
<em>mixing</em> several sources together to keep the combined signals from clipping.</p><h2id=sample-rate-and-bit-depth>Sample Rate and Bit Depth</h2><p>To make audio playable on a compact disc, for example, the computer must
generate 44,100 samples per second. The sample rate determines the highest
frequency which can be recorded or played back by the computer. A sampling
rate of 44.1 kHz means that the highest frequency which can be represented is
just under 22.05 kHz. Since normal human hearing lies within the range of
approximately 20 Hz to 20 kHz, this is commonly accepted as a reasonable
sample rate. Other commonly used sample rates include 48 kHz (e.g.
multi-effects pedals) or 96 kHz (DVD audio).</p><p>Each sample is recorded as a 16-bit number. One <em>bit</em> is a piece of
information which is either 0 or 1. If there are 16 bits together to make one
sample, then there are 2^16 (65,536) possible values for each sample.</p><p>Thus, we can say that CD-quality audio has a sample rate of 44.1 kHz and
a <em>bit depth</em> of 16 bits. Professional music recordings are usually mixed
using 24 bits to preserve the highest amount of detail before being mixed down
to 16 bits for CD. Older computer games have a distinctively rough sound,
using only 8 bits. By increasing the sample rate, we are able to record higher
sonic frequencies, and by increasing the bit depth, we are able to use a
greater <em>dynamic range</em> (the difference between the quietest and the loudest
sounds possible to record and play).</p><h2id=continuing>Continuing</h2><p>In the next chapter, we’ll launch Ardour on Ubuntu Linux and learn the basics
<scriptsrc=/ardour-tutorial/js/search.js?1652723066></script></div><divid=homelinksclass=default-animation><ul><li><aclass=paddinghref=/ardour-tutorial/en/><iclass="fas fa-home"></i> Home</a></li></ul></div><divid=content-wrapperclass=highlightable><ulclass=topics><lidata-nav-id=/ardour-tutorial/en/introduction/title=Introductionclass="dd-item parent"><inputtype=checkboxid=section-9278c07c1c4f7473c66529d5a0c6e688class=togglechecked><labelfor=section-9278c07c1c4f7473c66529d5a0c6e688></label><ahref=/ardour-tutorial/en/introduction/><b>1. </b>Introduction</a><ul><lidata-nav-id=/ardour-tutorial/en/introduction/conventions/title=Conventionsclass=dd-item><ahref=/ardour-tutorial/en/introduction/conventions/>Conventions</a></li><lidata-nav-id=/ardour-tutorial/en/introduction/what-is-digital-audio/title="What is digital audio?"class="dd-item active"><ahref=/ardour-tutorial/en/introduction/what-is-digital-audio/>What is digital audio?</a></li></ul></li><lidata-nav-id=/ardour-tutorial/en/getting-started/title="Getting started"class=dd-item><inputtype=checkboxid=section-6ba418844f4e8ce868bfa62d1bf5b9b1class=toggle><labelfor=section-6ba418844f4e8ce868bfa62d1bf5b9b1></label><ahref=/ardour-tutorial/en/getting-started/><b>2. </b>Getting started</a><ul><lidata-nav-id=/ardour-tutorial/en/getting-started/starting-ardour/title="Starting Ardour"class=dd-item><ahref=/ardour-tutorial/en/getting-started/starting-ardour/>Starting Ardour</a></li><lidata-nav-id=/ardour-tutorial/en/getting-started/overview-of-the-interface/title="Overview of the Interface"class="dd-item alwaysopen"><inputtype=checkboxid=section-65fa48091b8ede8e5c409cc42ad6af14class=togglechecked><labelfor=section-65fa48091b8ede8e5c409cc42ad6af14></label><ahref=/ardour-tutorial/en/getting-started/overview-of-the-interface/>Overview of the Interface</a><ul><lidata-nav-id=/ardour-tutorial/en/getting-started/overview-of-the-interface/editor-window/title="Editor window"class=dd-item><ahref=/ardour-tutorial/en/getting-started/overview-of-the-interface/editor-window/>Editor window</a></li><lidata-nav-id=/ardour-tutorial/en/getting-started/overview-of-the-interface/mixer-window/title="Mixer window"class=dd-item><ahref=/ardour-tutorial/en/getting-started/overview-of-the-interface/mixer-window/>Mixer window</a></li><lidata-nav-id=/ardour-tutorial/en/getting-started/overview-of-the-interface/recorder-window/title="Recorder window"class=dd-item><ahref=/ardour-tutorial/en/getting-started/overview-of-the-interface/recorder-window/>Recorder window</a></li><lidata-nav-id=/ardour-tutorial/en/getting-started/overview-of-the-interface/cue-window/title="Cue window"class=dd-item><ahref=/ardour-tutorial/en/getting-started/overview-of-the-interface/cue-window/>Cue window</a></li></ul></li><lidata-nav-id=/ardour-tutorial/en/getting-started/creating-tracks-and-busses/title="Creating tracks and busses"class=dd-item><ahref=/ardour-tutorial/en/getting-started/creating-tracks-and-busses/>Creating tracks and busses</a></li><lidata-nav-id=/ardour-tutorial/en/getting-started/importing-audio/title="Importing audio"class=dd-item><ahref=/ardour-tutorial/en/getting-started/importing-audio/>Importing audio</a></li><lidata-nav-id=/ardour-tutorial/en/getting-started/setting-up-the-timeline/title="Setting up the timeline"class=dd-item><ahref=/ardour-tutorial/en/getting-started/setting-up-the-timeline/>Setting up the timeline</a></li></ul></li><lidata-nav-id=/ardour-tutorial/en/recording-audio/title=Recordingclass=dd-item><inputtype=checkboxid=section-f34c0a5099ecaf52ba2ddf859ecf8564class=toggle><labelfor=section-f34c0a5099ecaf52ba2ddf859ecf8564></label><ahref=/ardour-tutorial/en/recording-audio/><b>3. </b>Recording</a><ul><lidata-nav-id=/ardour-tutorial/en/recording-audio/recording-audio/title="Recording audio"class=dd-item><ahref=/ardour-tutorial/en/recording-audio/recording-audio/>Recording audio</a></li><lidata-nav-id=/ardour-tutorial/en/recording-audio/understanding-routing/title="Understanding routing"class=dd-item><ahref=/ar