A combined level and correlation meter for Surround signals for the 5.1 - Standard
The levels of all six channels as well as the phase correlation between all combinations of two channels are represented,
so that defined statements are possible for the mono compatibility of a stereo and a Surround signal, in addition,
for the Stereo compatibility of a Dolby Prologic signal or a 5.1-Signals in the Downmix.
PAS-Surround Meter can be configured in a number of different ways, to accurately model the ballistics,
responses and graphics of a wide range of standard peak programme meters.
These meters currently include the following:
· IEC 268-10 Type I - Nordic N9
· IEC 268-10 Type IIa - BBC PPM
· IEC268-10 Type IIb - EBU PPM
· DIN 45406
Provides information about mutual phase-frequency relations between the signal of the left and right channel
and allows us to spot any possible irregularities.
These 'irregularities' may not have any significance in the case of stereo playback, but it should be
remembered that the material we record can also be played as a mono signal (for example, on TV or on one
of the radio stations which are broadcast or received in mono), and is worth sounding at least similar
to what we imagined.
The commonly applied DIN45406 with a head room of 6 dB referred to digital 0, Nordic
N9, BBC PPM,
EBU PPM and the
K-System (K-20, K-14, K-12) by Bob Katz are easily and individually recallable by using the Windows-function
keys F1 to F 8.
Download some avi-demos, there you can see the movements of the Surround Scope and Levels:
Surround Meter 5.1.wmv (347 kb)
Surround Moves.wmv (2.842 kb) no sound, but you will see...
a complex surround mix demands the full attention and concentration
of the sound engineer, the accompanying surround display has
to show the sound engineer at one glance the sound in its
total complexity. This is the reason why the design of this
display was kept factual and clear. At the left side above
the surround meter, a circular arrangement of the five sound
sources (speakers) can be found. This arrangement does not
comply with the arrangement of the famous (and dreaded) ITU-circle,
but it shows in a mathematically exact manner the present
mixing ratio of the five sources to each other by means of
the surround ball moving in the circle area. Especially the
often very critical balance between the front and rear speakers
is shown clearly and immediately here. However, this only
refers to the loudness of the five channels to each other
and not to their phase relation. The phase relation of a chosen
pair of channels will be shown on a correlation display below.
correlation display demonstrates the so-called correlation
level. For a better understanding, we will now make a short
excursion into the physiology of human hearing. To locate
the instruments of the stereo panorama, the ear does not only
assess the difference of sound level between the two channels
of a stereo-recording; the even more realistic impressions
originate from differences in the duration. When taking a
closer look of the hearing process in the nature, the reason
becomes obvious: To reach the ear which is turned away from
the sounds point of origin, the sound wave has to cover
a longer distance, hence arriving there later. From a technical
point of view, this delay is perceptible as a phase shift
between the channels.
If this phase shift is too big, the
signals are being deleted during a mono-reproduction process
as positive and negative half-waves of the vibrations compensate
each other and the mono sum becomes null. The dramatic thing
is that these deletes are different for every instrument;
hence the whole mix is shifted. So if you listen to a mix
in mono which sounds well in stereo, some instruments are
suddenly too low or the reverberation is missing.
Reverence Level: 0dBFs, -18 dBFs (european broadcast), -20 dBFs (american broadcast)
With the High OL POINT and Low OL POINT adjust it two borders, between which you can assign different colors to the bar line display. The color Base Color. applies to the segments of the bar line display below the Low OL POINT, the color Low OL Color. to the range between the two adjusted points, and the color High OL Color. to the range above the High OL POINT. Thus the appearance of the announcement can be changed variously and be adapted to your used representation.
Here you can select your digital drivers
Sound Driver Settings
After having started the programme, you should first of all
relocate the audio channels of your sound card in the available
channel routing. Therefore you can either use the internal Windows-MME
audio driver or installed ASIO-drivers if they are activated.
The PAS Surround Meter has the ability to approach all known
audio drivers; the sampling frequency (48Khz,44Khz ) or the
applied Bit resolution is not of importance here. In the case
that a Bit/splitting with 88.2 Khz or 96 Khz is used via an
ADAT-Interface, however, the configuration has to be carried
out via two separate Opto-ADAT inputs.
A double seizure of the
surround inputs with similar input channels will cause an error
message!! In this case you have to restart the PAS Sourround
Meter and feed the audio channels correctly.
course it is also possible to use the surround meter as a usual
:: Correlation Settings
this settings dialogue, the user can carry out his individual
adjustment of all parameters of the correlation level indicator.
correlation as Bars
the user can chose between 2 different types of display diagrams.
The bar diagram always refers to null. We are aware that the real
correlation does not have a relation to null, but this diagram
helps to keep a better overview. Of course this is a matter of
taste. This is why we also put the lines display as default.
268-10 Type I - Nordic N9
IEC 268-10 Type IIa - BBC PPM
IEC268-10 Type IIb - EBU PPM
dB Full Scale
recommend these soundcards:
(balanced analogue I/O (8x XLR/TRS mic/line with 48V phantom
power),ADAT I/O (up to 48kHz), 8 channels (up to 96 KHz) switchable
to S/PDIF optical (TOSlink), S/PDIF I/O (coax), AES/EBU I/O,)
ESI MaXiO EX8000
Connecting a multichannel AV Amplifier to a multimode sound card (analog way)
FOR DIGITAL IT IS JUST 1 CABLE LIKE THIS: (S/P-Dif, optical und coax, ADAT interface, AES/EBU In/Out )
FOR DIGITAL IT IS JUST 1 CABLE LIKE THIS:
(S/P-Dif, optical und coax, ADAT interface, AES/EBU In/Out )
F1 = IEC 268-10 Type I - Nordic F1 = Nordic N9
= DIN 45406
= IEC 268-10 Type IIa - BBC PPM
F4 = IEC268-10 Type IIb - EBU PPM
F6 = K-System K-20
F7 = K-System K-14
F8 = K-System K-12
= delete max peak and peak offset
For the operations of the PAS Surround meter the following minimum requirements
IBM PC or compatibly with 800 MgHz Pentium
- 128 MB RAM
- VGA monitor and diagram map with 32 bit colors or more, dissolution
mind. 1024 x 768 recommended
- Windows compatible 16-Bit-Multimode-Soundcard (at least 3 Stereo
- mouse or other showing equipment
- 10 MB place on the disk
Microsoft Windows 2000/XP/Vista 32
- Windows MME sound drivers
The 5.1-Format offers completely independent channels, with which
therefore also the rear loudspeakers can be separately from each
other headed for and which entire frequency range to take off.
This extended possibilities open clearly with placing the instruments
in the area, and klangliche changes by Matrizierung cannot even
develop. Also with the center channel it concerns an individual
channel, with whose separate control beyond the possibilities
of a LCR Panpots however it should be considered that the phantom
center between left and right channel nevertheless further existed
and with same signal portions in the center channel can cause
extinctions. On the other hand a situation can be created by skillful
placing of some events in the center channel and other one in
the phantom center, with which the center signals before a formed
texture seem to stand for through left and right channel, which
seems to move on change of the hearing position even opposite
the center channel.
The name 5,1 states that beside the five Fullrange loudspeakers
an additional Subwoofer is used, which is likewise headed for
by a discrete channel. This as LFE (Low frequency Effects) did
not designate channel serves however for the recording the satellite
loudspeakers of completing bass signal. That would be already
not meaningful, because with music production does not admit the
specific data of the respective hearing plant are. Thus if the
frequency response of the five main loudspeakers is not enough
far enough down there and if these are to be supported therefore
also by the Subwoofer, then this is to be realized rendition-laterally,
as it already admits for example from Stereo Subwoofer plants
The LFE channel serves excluding the recording of low-frequent
effects additionally for the Fullrange range of the main loudspeakers.
Here extremely deep basses with high levels and therefore large
diaphragm deflections are well waived, which do not load the main
loudspeakers any longer.
When mixing in the 5.1-Format clay/tone engineer does not enjoy
nevertheless all liberties of the completely discrete channels,
because many consumers do not operate their Surround Abspielgeraete
at all in the Surround mode. Here an automatic Downmix then often
takes place in the playback unit. This leads on the one hand to
the fact that with the Platzieren for example thundering a thunderstorm
exclusively in the LFE channel dead silence will prevail completely
surely with the users, who did not attach Subwoofer, why one avoids
such extreme attitudes with production and always also on the
main loudspeakers should put supplementing signal portions. On
the other hand however the rules there always apply for the attention
of the phase positions with the pro log IC or Stereo format in
the long run also to a 5.1-Mischung, with a later to count automatic
Downmix are. But the phase relationships between all pairs of
channels must be correct, and appropriate correlation announcements,
how them offer the PAS Surround meter, are very helpful.
By the discrete center channel, significant signal portions effects
in the LFE channel, important from the rear loudspeakers and,
the speech cannot be when exclusive hearing the left and right
channel of Stereokompatibilitaet. Therefore its own mixture is
to be made for Stereo listeners, which does not have to be noted
however obligatorily on two further channels of the Surround Tontraegers.
The format Dolby digital contains meta data so mentioned, in which
the controlling of the automatic Downmixes can be given in the
playback unit by producing clay/tone engineer. Since this has
also effects on the sum levels, the PAS Surround meter refers
such measurements into its concept also.
to the homepage