SPL Atmos 5.1 User manual

Manual
Atmos 5.1 Surround Miking System

2
Version 1.0 E – 12/2003
R&D: Wolfgang Neumann
This user's guide contains a description of the product. It in no way represents
a guarantee of particular characteristics or results of use. The information in this
document has been carefully compiled and verified and, unless otherwise stated or
agreed upon, correctly describes the product at the time of packaging with this docu-
ment.
Sound Performance Lab (SPL) continuously strives to improve its products and
reserves the right to modify the product described in this manual at any time without
prior notice. This document is the property of SPL and may not be copied or repro-
duced in any manner, in part or fully, without prior authorization by SPL.
Special thanks to:
Gerd Jüngling from ADT, who kindly provided the circuitry for the surround panning
matrix. Dirk Brauner Röhrengerätemanufaktur for the good collaboration.
Contact
Sound Performance Lab
Sohlweg 55, 41372 Niederkruechten, Germany
Fon [phone]
Fax [phone]
Mail: [e-mail]
Internet: www.soundperformancelab.com
Atmos 5.1 Surround Miking System, Model 9843 User’s Guide
© 2003 SPL electronics GmbH. All rights reserved. Technical specifications and appearance subject to change without notice.

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Contents
Atmos 5.1 – the complete miking system for surround recordings ................... 4
Installation ........................................................................................................ 5
Control Elements ............................................................................................... 6
Standard Recording Setup ................................................................................ 11
Integration of additional microphones/stereo submix ...................................... 12
Integration of additional microphones/stereo submix ...................................... 13
A typical recording setup .................................................................................. 14
Specifications ................................................................................................... 15
Block diagram ................................................................................................... 16
Introduction
Dear customer,
thanks for using the Atmos 5.1 system. We wish you have as much fun working with
it as we had during the development of this extraordinary recording equipment.
The complete Atmos 5.1 system includes Atmos 5.1 controller, the Adjustable
Surround Microphone 5 (ASM 5), a separate power supply unit and a multicore cable
(length ca. 25 meters/27.5 yards).
The Atmos 5.1 system allows to record the original event and all of its authentic
spatial content with highest precision. It demonstrates the significant difference
between discrete surround recordings and artificial surround mixes with breath-
taking results. To reliably achieve these amazing results, the Atmos 5.1 provides
everything you need to record virtually any audio event.
Due to its analog structure, the audio signals are compatible with any common
surround format—DVD-A, DVD-V, SACD, AC3, DTS, MLP... you name it, Atmos 5.1 can
deliver it.
With its ingenious ASM 5 „star frame“ array based on Brauner VM1 mic elements
and custom-designed, hand-built Atmos 5.1 controller, this unique system offers an
unparalleled combination of uncompromising audio quality and ultimate flexibility.
Most importantly, the Atmos 5.1 system is a breeze to use and can be set up in
minutes, arming you for the most convincing 5.1 recordings you‘ve ever experi-
enced.

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The Atmos 5.1 is a fully-featured stand-alone surround miking system for surround
productions in any known format.
The ASM5 surround microphone combines five microphones elements in an ideal
setup for surround recordings. Each one is directly assigned to one of the five
surround channels and can be processed discretely with the Atmos 5.1 controller. All
microphone elements are movable and their polar patterns can be set up individu-
ally, e g. to effectively compensate for disadvantageous room acoustics.
The Atmos 5.1 features a complete panorama matrix, an LFE section and a monitoring
section, thus all you need to create a surround mix. An External Inputs section allows
to integrate additional stereo mixes in a surround mix—either for the insertion of
additional microphones or to upgrade stereo consoles with surround capabilities.
The Atmos 5.1 system operates fully analog to ensure independence from any storage
or transmission format.
The ASM 5 surround microphone
The ASM 5 is based on Brauner VM1 mic elements. Three microphone elements are
assigned to the L/C/R channels, two further mics are used two capture the informa-
tion for the rear surround channels. Together they form a perfectly balanced surround
microphone.
Each microphone head can be moved by +/- 90° horizontally, the polar patterns can
be adjusted remotely from the Atmos 5.1’s ASM5 Pattern Control—infintely variable
for each capsule from omnidirectional through cardioid/hypercardioid to figure-of-
eight. A pad switch allows to reduce the microphone’s sensitivity by -16 dB.
The I/Os of both the ASM 5 and the Atmos 5.1 are built upon transformers to drive
wirings of up to 250 meters/275 yards. The ASM 5 can be installed on usual micro-
phone stands.
Atmos 5.1 controller
The Atmos 5.1 is equipped with five matched high precision microphone preamps
featuring SPL‘s triple gain stages to capture the superb sound of Brauner‘s ASM 5
microphone in the most transparent, noiseless and uncoloured way.
The microphone preamps also feature SPL‘s S er voD ri ve -Tec hn ology which detects
voltage differences (DC-offset) between the positive and negative paths of the ampli-
fying stages. Any offset increases noise and distortion and therefore compromises
the signal quality. ServoDrive minimizes DC-offsets to values between 0mV and 2mV.
The recorded signal contains less noise and distortion and improved tonal transpar-
ency.
Further features include Lundahl input transformers, pads, phase reverse, phantom
power, low cut filters, a switchable insert and tape send/returns. All switches are
luminated. High quality switches and relays with gold plated contacts are used
throughout.
Motorized gain controls
An important feature of the Atmos 5.1 are its motorized gain controls. While changing
the preamplification the relative loudness relationships between all five microphones
are maintained.
A Master Gain switch enables motorized control over all five microphones preampli-
fiers by just turning one control. This is especially important when re-adjustment of
the preamplification becomes necessary during recording to avoid negative effects
on the spatial coherence and phase stability.
Atmos 5.1 – the complete miking and system for surround recordings

5
The Atmos 5.1 unit and the PSU should not be installed near units which produce
strong magnetic fields or extreme heat. Do not install the units directly above or
below power amplifiers. Especially the ventilated PSU should be installed at a place
with sufficient air circulation.
The ASM 5 has to be placed the way that the LCR heads of the microphone (those
closer to the microphone center/90° angle) are facing the sound source. Be sure to
place the microphone as high as necessary to avoid ground reflections and comb
filtering effects. Usually the best position for the ASM 5 is right on the crossing
between the direct sound field and the diffuse sound field.
BEFORE switching on the PSU, you have to connect the ASM 5 via the multicore lead
to the Atmos 5.1 unit. Pay attention to fit the bayonet joints properly. Proceed in the
same way to connect the Atmos 5.1 unit to the PSU. Check that the voltage details
quoted on the PSU back panel correspond to your local mains electricity supply. Use
a minus (-) screwdriver to set the voltage selector to the required voltage.
By the way ... the PSU uses two 1,6 A slow fuses.
On the Atmos 5.1 unit, please check the positions of the ASM 5 Pattern Controls. We
recommend to start with the cardioid pattern characteristic for all five microphones
(controls in center position).
Please check the position of the External Mic Input switches on the back panel of the
Atmos 5.1. If these switches are depressed, the corresponding channels of the ASM
5 are deactivated. Depress them only to activate external microphones connected to
the XLR inputs.
Now switch on the PSU. Check the 9 LEDs on the front panel of the PSU. They indi-
cate that all 9 voltages are generated properly. Chassis ground and AC ground can
be disconnected with the Ground Lift switch (GND LIFT) on the back panel. This can
help to eliminate hum. An AC power cord is included to feed the IEC-spec, 3-prong
connector.
After switching in the PSU, proceed as follows:
1) Turn the Mic Gain of Channel 5 (master) control fully counter clockwise (0 dB).
2) Press the Channel Lock button at Channel 5 (all other channels follow automati-
cally to 0 dB).
3) Set the Master Mic Gain control to the 12 o’clock position (all other mic gain
controls follow precisely). Now the VU meters indicate modulation.
4) Setthe Fader controls to the 0 dB position (used for monitoring only, see “Standard
Recording Setup“).
5) Press the Direct button on every channel to route the signal directly to the Master
and Monitoring Outputs.
6) In the Monitor section, set the control to the 12 o’clock position. The L/R switch
has to be activated for 5.1 monitoring.
Installation

6
Input Section
Gain settings can be adjusted individually for each channel. The MIC Gain control
of channel 5 can be specified as Master Gain control to control all 5 gain settings at
a time—the motorized potentiometers ensure coherent gain settings for all chan-
nels with highest precision.
The microphone inputs are equipped with phantom power supply, switchable
insert, pad (-25 dBu), phase reverse and high pass filter (100 Hz/50 Hz).
For direct recordings of the preamplified signals recording devices like a multitrack
recorder can be connected to the insert Tape Send. Signals coming back from the
recorder can be connected to the insert Tape Return, for example to use the pano-
rama matrix or further Atmos 5.1 features.
The VU meters display the input level of each channel after the preamplifier
stages.
The insert Tape Return can also be used like a usual line input for external sources,
e g. to use all Atmos 5.1‘s features for a surround mix.
Fader
The fader allows adjustments of the signal level that is routed either to the direct
channel outputs, to the panorama matrix or to the outputs.
Control elements

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5.1 Routing
The Atmos 5.1 controller offers a complete routing and panorama matrix. With the
routing selectors the signals can be assigned to any of the the surround busses,
with the panorama matrix they can be positioned exactly. The Direct switch allows to
bypass the panorama matrix, routing the signal to the output of a surround bus.
F/S Pan
Front/Surround Pan blends the signal from the front to the rear channels or vice
versa.
Control Elements

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L/C/R Pan and Divergence
L/C/R panning determines the position of a signal in the L/C/R panorama. The diver-
gence control allows to attenuate the L and R channels in relation to the center
channel.
LFE signals
The LFE signal can be composited from the front, surround, and centre channels. A
24dB Butterworth low-pass filter at 130Hz can be activated to only let those frequen-
cies pass up to where localisation begins. In the mixing/premastering stage the
frequency can be reduced to the value required for i.e. AC3 or DTS encoding. If the
low-pass filter is not activated, a mono composite of the selected mic inputs can be
send to a separate sub/LFE processor.
Control elements

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Stereo In/Out
Two additional balanced inputs are provided to mix a stereo source from additional
room mics or from a multichannel sub mix to the front, centre and surround channels.
The stereo outs allow the stereo source to be processed or recorded with further
units.
Mic Distance
Two switchable allpass stereo width controls can be used to influence the stereo
width of each coherent channel pair (L and R, L S and LR). This way, variable distances
between the microphone heads can be simulated electronically. The Mic Distance
section is equipped with a hard bypass and a mono switch. Two phase meters display
the L/R & SL/SR correlation (either with Mic Distance control active or in bypass).
Control Elements

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ASM 5 Pattern Control
The ASM 5 provides infinitely variable adjustments of the polar pattern characteristic
for each microphone from omnidirectional up to figure-of-eight. These adjustments
can be made remotely from the Atmos 5.1 and can be monitored while recording.
A pad reduces the microphone‘s sensitivity by -16 dB.
Monitoring
Both during recording and mixing the monitoring volume can be adjusted by the aid
of an electronic circuitry that ensures precise, coherent volume control of all six chan-
nels. The Monitor Volume control also sets the volume for headphones connected to
the front. The 5.1/Stereo switches determine which channels are monitored.
PPM Meters
The PPM meters display the levels at the output of each bus. Values range between
-48 dBu und +9 dBu and are displayed in steps of 3 dB.
Control Elements

11
The Standard Recording Setup is the basic
configuration for “purist” 5.1 recordings. The
DTRS is connected right after the preamp stage
to record unprocessed microphone signals.
Additionally the 6th recorder’s channel can be
used to record the sub bass signals, the 7th
and 8th channel can be used to record a stereo
mixdown.
This setup can be modified or extended in many
ways, for example by connecting an analogue
multitrack recorder to the master outputs (up to
two recorder simultaneously via XLR and Jack)
for recordings of the processed signals – while
the DTRS still is recording as described above
(e. g. backups).
When using a stereo headset, the L/R, C, SL/SR
and SUB channels can be monitored individu-
ally (see Monitor section).
Insert Sends (XLR or Jack)
to DTRS inputs
ASM 5
Sub Bass (XLR or Jack)
Stereo Mix (XLR or Jack)
DTRS outputs to Insert
Returns (XLR or Jack)
5.1 Monitoring
Standard Recording Setup

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Integration of additional microphones/stereo submix
Stereo master outs to
External Inputs L & R
Additional microphones
The Atmos 5.1 controller allows to integrate
additional microphones as stereo or surround
submix. During monitoring, the level settings for
the ASM 5 determine the mix relation between
ASM5 and additional microphones.
In general additional stereo mixes can be
connected to the External Inputs. For integra-
tion of additional microphones as a stereo mix,
an external sub mixer, connected to the External
Inputs L&R, is needed to create the mix.

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Integration of additional microphones/surround submix
5.1 master outs to XLR Returns of the Atmos 5.1
Additional microphones
AtmosXLRsends
to DTRSor DASH
For insertion of additional surround submixes,
the Insert Send and Insert Return sockets on
the Stmos 5.1 rear panel must be connected
with a short patch cable. The Insert buttons of
the Iput section on the front panel need to be
depressed.
The additional surround mix is created on
a mulitchannel-ready submixer and and
connected to the XLR Insert Returns of the
Atmos 5.1 controller.
The signals can be sent to a DTRS/DASH via the
XLR Insert Sends on the Atmos 5.1.

Fliess
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A typical recording setup: SACDrecording with Atmos 5.1 and additional microphones

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Frequency range
Mic Direct Out @ 18 dB Gain: 10 Hz-180 kHz (+/-3 dB, Phase –2°)
(Channel Out, Master Out, Monitor Out as above)
Mic Direct Out @ 60 dB Gain: 10Hz-180 kHz (+/-3 dB, Phase –2°)
(Channel Out, Master Out, Monitor Out as above)
CMRR 100Hz 1 kHz 10 kHz
18dB Gain: -79 dB -79 dB -60 dB
34dB Gain: -66dB -66 dB -52dB
60dB Gain: -45 dB -45dB -32dB
w. Pad -16 dB @ 18 dB Gain: -90 dB -90 dB -79 dB
THD & N (Mic Direct Out) 1 kHz 10 kHz
60dB Gain: 0,22% 0,24 %
50 dB Gain: 0,07 % 0,07 %
40dB Gain: 0,022 % 0,023 %
30dB Gain: 0,007% 0,007 %
18dB Gain: 0,002% 0,0023 %
THD & N (Monitor Out) 1 kHz
60dB Gain: 0,24%
50 dB Gain: 0,07 %
40dB Gain: 0,03 %
30dB Gain: 0,034 %
18dB Gain: 0,031 %
S/N ratio (A-weighted)
150 Ohm generator, 22 Hz-22kHz filter, 60dB Gain@150Ohm
Mic Direct Out: -66,8 dB
Channel Out: -66,8dB
Master Out: -66,8 dB
Monitor Out: -66,8dB
50 dB Gain@all: -77,2 dB
40dB Gain@all: -85,8 dB
30dB Gain@all: -93,6 dB
18dB Gain@all: -96,4 dB
w. PAD -16 dB @ 18 dB Gain: -97,5dB
Specifications

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Block diagram