<h2>Introduction</h2>
<p>
- An engineer reading and using audio level meters compares to a musician
- reading or writing sheet-music. Just like there are virtuoso musicians
+ An engineer reading and using audio level meters compares to a musician
+ reading or writing sheet-music. Just like there are virtuoso musicians
who can't read a single note, there are great sound-engineers who just
- go by their ears and produce great mixes and masters without ever looking
+ go by their ears and produce great mixes and masters without ever looking
at a single meter.
</p>
<p>
- Yet, if you want to work in or with the broadcast industry, it is
+ Yet, if you want to work in or with the broadcast industry, it is
usually unavoidable to use meters.
</p>
<p>
- Audio level meters are very powerful tools that are useful in every
+ Audio level meters are very powerful tools that are useful in every
part of the entire production chain:
</p>
<ul>
- <li>When tracking, meters are used to ensure that the input
- signal does not <dfn>overload</dfn> and maintains reasonable
+ <li>When tracking, meters are used to ensure that the input
+ signal does not <dfn>overload</dfn> and maintains reasonable
<dfn>headroom</dfn>.</li>
- <li>Meters offer a <dfn>quick visual indication</dfn> of a
+ <li>Meters offer a <dfn>quick visual indication</dfn> of a
activity when working with a large number of tracks.</li>
- <li>During mixing, meters provide an rough estimate of the
+ <li>During mixing, meters provide an rough estimate of the
<dfn>loudness</dfn> of each track.</li>
- <li>At the mastering stage, meters are used to check
- compliance with upstream <dfn>level</dfn> and <dfn>loudness
+ <li>At the mastering stage, meters are used to check
+ compliance with upstream <dfn>level</dfn> and <dfn>loudness
standards</dfn> and to optimize the <dfn>loudness range</dfn>
for a given medium.</li>
</ul>
<h2>Meter Types</h2>
<p>
- A general treatise on metering is beyond the scope of this
+ A general treatise on metering is beyond the scope of this
manual. It is a complex subject with a history…
For background information and further reading we recommend:
</p>
<dl>
<dt>Digital peak-meter</dt>
- <dd>A <dfn>Digital Peak Meter</dfn> displays the absolute maximum signal
- of the raw audio PCM signal (for a given time). It is commonly used when
- tracking to make sure the recorded audio never clips. To that end, DPMs
+ <dd>A <dfn>Digital Peak Meter</dfn> displays the absolute maximum signal
+ of the raw audio PCM signal (for a given time). It is commonly used when
+ tracking to make sure the recorded audio never clips. To that end, DPMs
are always calibrated to 0 <abbr title="DeciBel Full
Scale">dBFS</abbr>, or the maximum level that can be represented digitally
- in a given system. This value has no musical reason whatsoever and depends
- only on the properties of the signal chain or target medium. There are
- conventions for <dfn>fall-off-time</dfn> and <dfn>peak-hold</dfn>, but no
+ in a given system. This value has no musical reason whatsoever and depends
+ only on the properties of the signal chain or target medium. There are
+ conventions for <dfn>fall-off-time</dfn> and <dfn>peak-hold</dfn>, but no
exact specifications.
<p>
- Various conventions for DPM fall-off times and dBFS line-up level can be
+ Various conventions for DPM fall-off times and dBFS line-up level can be
chosen in <kbd class="menu">Edit > Preferences > GUI</kbd>.
</p>
</dd>
<dt>RMS meters</dt>
<dd>An <dfn><abbr title="Root Mean Square">RMS</abbr>-type meter</dfn>
- is an averaging meter that looks at the energy in the signal. It
- provides a general indication of loudness as perceived by humans. Ardour
+ is an averaging meter that looks at the energy in the signal. It
+ provides a general indication of loudness as perceived by humans. Ardour
features three RMS meters, all of which offer additonal peak indication.
<ul>
<li><dfn>K20</dfn>: A meter according to the K-system introduced by Bob
</dd>
<dt>IEC PPMs</dt>
- <dd><dfn><abbr title="International Electrontechnical Commission">IEC</abbr>-type
- <abbr title="Peak Programme Meters">PPM</abbr>s</dfn> are a mix between DPMs and
- RMS meters, created mainly for the purpose of
+ <dd><dfn><abbr title="International Electrontechnical Commission">IEC</abbr>-type
+ <abbr title="Peak Programme Meters">PPM</abbr>s</dfn> are a mix between DPMs and
+ RMS meters, created mainly for the purpose of
interoperability. Many national and institutional varieties exist (<abbr
title="European Broadcasting Union">EBU</abbr>, <abbr title="British Broadcasting
- Corporation">BBC</abbr>, <abbr title="Deutsche Industrie-Norm">DIN</abbr>).
+ Corporation">BBC</abbr>, <abbr title="Deutsche Industrie-Norm">DIN</abbr>).
<p>
- These loudness and metering standards provide a common point of
- reference which is used by broadcasters in particular so that the
+ These loudness and metering standards provide a common point of
+ reference which is used by broadcasters in particular so that the
interchange of material is uniform across their sphere of influence,
regardless of the equipment used to play it back.
</p>
<p>
For home recording, there is no real need for this level of
- interoperability, and these meters are only strictly required when
- working in or with the broadcast industry. However, IEC-type meters have
- certain characteristics (rise-time, ballistics) that make them useful
+ interoperability, and these meters are only strictly required when
+ working in or with the broadcast industry. However, IEC-type meters have
+ certain characteristics (rise-time, ballistics) that make them useful
outside the context of broadcast.
</p>
<p>
- Their specification is very exact, and consquently, there are no
+ Their specification is very exact, and consquently, there are no
customizable parameters.
</p>
</dd>
-
+
<dt>VU meters</dt>
- <dd><dfn><abbr title="Volume Unit">VU</abbr> meters</dfn> are the dinosaurs (1939)
+ <dd><dfn><abbr title="Volume Unit">VU</abbr> meters</dfn> are the dinosaurs (1939)
amongst the meters. They react very slowly, averaging out peaks.
- Their specification is very strict (300ms rise-time, 1–1.5% overshoot,
- flat frequency response). Ardour's VU meter adheres to that spec, but for
+ Their specification is very strict (300ms rise-time, 1–1.5% overshoot,
+ flat frequency response). Ardour's VU meter adheres to that spec, but for
visual consistency it is displayed as a bar-graph rather than needle-style
(more below).
</dd>
</ul>
<p>
They all share the same configuration and color-theme which is available in
- preferences and the theme-manager. Settings for the Peak and RMS+Peak meters
- as well as VU meter standards are found in
+ preferences and the theme-manager. Settings for the Peak and RMS+Peak meters
+ as well as VU meter standards are found in
<kbd class="menu">Edit > Preferences > GUI > Metering</kbd>.
</p>
<p>
</p>
<img class="right" src="/images/meter-preferences.png" alt="" />
<p>
- Regardless of meter type and standard the meter display will highlight red if
+ Regardless of meter type and standard the meter display will highlight red if
the signal on the given channel exceeds the configured peak threshold.
</p>
<p>
<h2>Overview of meter types</h2>
<p>
- The figure on the left shows all available meter-types in Ardour 3.4 when fed with a
+ The figure on the left shows all available meter-types in Ardour 3.4 when fed with a
-18 dBFS 1 kHz sine wave.
</p>
alt="Bar-graph meters in Ardour" />
<p>
- Due to layout concerns and consistent look&feel all meters available in
+ Due to layout concerns and consistent look&feel all meters available in
Ardour itself are bar-graph type meters. Corresponding needle-style
meters—which take up more visual screen space—are available as
LV2 plugins (see image on the right):
projects / ardour-manual / blobdiff