Transcript Electronically controlled dispersion measurement system

by
presents:
Outline System “E.T.”
Electronically controlled dispersion measurement
turntable
 System
components
 System properties
 New features
 Make-up of the basic system
 Installation
 Manual control
 Control via the “ET Commander”
 Examples of system use
 Example 1: Polar measurements - 1 axis
 Example 2: Polar measurements - 2 axes
 Example 3: Polar measurements of Microphones
 Example 4: Listening tests
 Some references
 Technical specifications
Outline “E.T.” system components
Outline ET2-ST2: Electronically controlled
dispersion measurement turntable
The system comprises:
• ET 2
Electronic
Controller
• ST 2
Turntable
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Properties of the Outline “E.T.” system
Outline ET2-ST2: Electronically controlled
dispersion measurement turntable
An Outline “E.T.” system allows to control the rotation of one or more turntables. It's
thus possible to carry out acoustic measurements on loudspeaker systems and obtain
dispersion graphs.
 Outline “E.T.” is a manual or automatic rotation system for carrying
out dispersion measurements.
 Outline “E.T.” can be interfaced with all analog measurement
systems, in both manual mode and automatic mode, using the
sophisticated Outline ET Commander software, which controls all
its movements.
 Since it emits and receives TTL sync pulses, Outline “E.T.” can be
directly interfaced with computerized measurement systems which
recognise or generate this TTL pulse (LinearX LMS®, DRA
MLSSA®, GoldLine TEF 20®, Audiomatica Clio®, etc.), as well as
with others, by means of the ET Commander software in a
Windows® (95, 98, NT) multitasking system.
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 These possibilities make the Outline “E.T.” system unique for use in
research labs in which several sound reproduction or measurement
systems have to be moved simultaneously.
Properties of the Outline “E.T.” system
Outline ET2-ST2: Electronically controlled
dispersion measurement turntable
The 2D polar diagram shown alongside was drawn using an LMS® system: it shows the
SPL response values of a speaker enclosure measured at 500, 800,1K, 2K e 4K,10K Hz,
while carrying out four complete rotations in 5° steps.
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Properties of the Outline “E.T.” system
Outline ET2-ST2: Electronically controlled
dispersion measurement turntable
This 3D diagram was drawn using an MLSSA® system: it shows the SPL response
curves of a speaker enclosure (freq. between 200 and 20kHz) +/- 180° as a function
of the angle of rotation referred to the measurement “Z” axis (0°).
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Properties of the Outline “E.T.” system
Outline ET2-ST2: Electronically controlled
dispersion measurement turntable
This diagram shows the polar response of a microphone plotted in an anechoic chamber
using a calibrated wide-band source and rotating the microphone as indicated in the
example alongside.
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New features introduced
Outline ET2-ST2: Electronically controlled
dispersion measurement turntable
After the success of the first version of the ET1-ST1 turntables, Outline modified the ET
1 control unit, now called “ET 2”, with the following upgrades, in between ST1 was
improved mechanically and named ST2:
 “ET 2” is completely controllable via Personal Computer by means of the
Outline “ET Commander” program.
 “ET 2” can control TWO “ST 2” (*) turntables: the first (Master) rotates
clockwise, whereas the second (Slave) rotates counterclockwise.
 The Outline “ET Commander” program can control up to TWO ET 2 units,
driving two ST 2 (*) turntables, which can therefore rotate separately and
freely (plus other two “slave” turntables).
 With “ET Commander”, the turntable can be rotated in both directions
(clockwise or counterclockwise), in either automatic or manual mode.
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 “ST2” now can rotate also a suspended load up to 100 Kg. with 30 Kg.
of twisting moment, thanks to a 20% more powerful motor with stamped
steel gear.
(*) The second ST 2 unit is optional
Make-up of the basic system
Outline ET2-ST2: Electronically controlled
dispersion measurement turntable
The basic system of Outline “E.T.” comprises:
 1 “ET 2” electronic
controller
 1.8m. cable (DB9M –
DB25M) for
connecting the ET 2
to the PC LPT
 1 “ST 2”
turntable
 1 “ET Commander”
software for controlling
the system via PC with
Microsoft Windows®.
 0.5m. cable with one
DB9F (for
connection to the
measurement cards'
TTL output).
The equipment is completed by:
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 10m. cable (DB9 –
Micro) for connecting
the ET 2 and ST 2
 1 220V power cord for ET 2
 10 - 10MA hexagon socket screws
for fixing the ST 2 to the dedicated
hardware or optional “STAND-ST2”
stand.
 1 - 8mm hexagon key.
Installation – Connecting the ET 2 to the ST 2
 The DB9/F connector of the 10 m.
multipole cable (supplied as
standard) must be connected to the
“Turntable” DB9/M connector on the
rear of the ET 2.
 The other end of the cable must be
connected to the connector on the
ST2
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Outline ET2-ST2: Electronically controlled
dispersion measurement turntable
Rear of the ET 2
First turntable
Installation – Connecting a SECOND ST2 UNIT
With ET 2, two ST 2 units can be
controlled:
 The DB9/F connector of the
10m. multipole cable (supplied
as standard) of the SECOND
ST2 unit must be connected to
the “Turntable (Reverse Slave)”
DB9/M connector on the front
panel of the ET 2.
Outline ET2-ST2: Electronically controlled
dispersion measurement turntable
Front of the ET 2
 The other end of the cable must
be connected to the connector
on the ST 2.
The second ST2 unit will be in sync
with the first, but will rotate in the
opposite direction (slave conditions).
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“ET Commander” can control two ST2
units independently (plus two slaves
more), but in this case, two ET 2 units
must be used.
Second turntable
Installation - Connecting the ET 2 to a P.C.
with “ET Commander”
The new ET 2 control unit is fully controllable via
Personal Computer thanks to Outline's “ET
Commander” software:
 Connect the DB9/DB25 cable
(supplied as standard) to the
parallel port of the Personal
Computer and the
“Computer Parallel Port”
DB9F connector on the front
panel of the ET 2 unit:
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 When initiated, “ET
Commander” runs a test of
the ST2 turntable's status,
returning it to the 0° (zero
degrees) position.
Outline ET2-ST2: Electronically controlled
dispersion measurement turntable
Personal Computer
LPT
Outline ET2-ST2: Electronically controlled
dispersion measurement turntable
Installation - Connecting the ET 2 to the Measurement Card
The cable supplied with just one DB9 is for permanent connection to the measurement
system. For example, with LinearX LMS, it will be soldered directly to the DB15 connector.
For DRA MLSSA on the other hand, an (optional) normal DB9-DB9 cable must be used.
 To synchronize the movement of the ST 2 unit, using the TTL output of the
measurement card used, connect the DB9M connector of the 0.5m. cable
supplied as standard to the “Computer” connector on the rear panel of the
ET2. The cable's conductors (centre and ground) must be connected to the TTL
output signal PIN and the earth of the measurement card respectively.
 a second ST 2 turntable is connected, it will also be synchronised with the first
by means of the TTL pulse generated by the audio card, but will rotate
counterclockwise.
Rear of the ET 2
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Once the required angular
movement is finished, the
ET 2 unit generates
another TTL pulse (with
the required delay setted
by the user) to
communicate the audio
card that it can begin a
new measurement.
Outline ET2-ST2: Electronically controlled
dispersion measurement turntable
Manual control – ET 2 controls:
“Switch on”, “Reset” and “TTL Output Delay”
 This switch
switches on
the ET 2
and powers
the ST 2
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 The “RESET”
button on the
ET 2's front
panel returns
the ST 2 to a
position of zero
degrees (0°).
 The “TTL OUTPUT TIME ADJ” trimmer on the ET 2's
front panel is used to adjust the running time of the
measurement cycles by introducing a delay in
sending the TTL pulse, which can be set between 3
and 25 seconds. It can be used where the measuring
program (for example MLSSA®), provides for the
continuation of measurement after a pulse is
received from the ET 2 control unit.
Outline ET2-ST2: Electronically controlled
dispersion measurement turntable
Manual control – ET 2 controls:
“Deg Step”, LED and “Manual” buttons
 The “DEG STEP” selector on ET 2's front panel is used to
select the step (in degrees) of the movement which ST 2 will
carry out for each pulse received via automatic command
from a measurement card. This selector is only used for the
automatic control of the turntable by a measurement card
(connected to the “COMPUTER” connector on the rear
panel). If ET Commander is used, the position of this
selector is unimportant.
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 The two LEDs under
the “AUTO” printing
indicate the direction
of rotation of the ST 2
(COUNTER/CW CLOCKWISE) in both
Manual and
Automatic mode.
This is useful when
ST 2 can't be seen
directly from the
measurement
position.
 The two buttons
under “MANUAL”
are used to
manually turn the
ST 2
counterclockwise
(COUNTER/ CW)
or clockwise
(CLOCK WISE)
Manual control – Rotation
ST 2 turntable rotation can be controlled either
manually or automatically.
 Manual movement is carried
out using the control
buttons on the ET 2's panel
or the Outline “ET
Commander” software's
“virtual" buttons.
 Automatic movement is
carried out with the custom
“macro” controls available
using Outline “ET
Commander” software.
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 Automatic movement is also
carried out with “macro”
controls created “ad hoc” or
already available in the
measurement software
controlling TTL pulses on
input and/or output, such as
LMS, MLSSA, TEF 20 or Clio.
Outline ET2-ST2: Electronically controlled
dispersion measurement turntable
Control with “ET Commander”
Outline ET2-ST2: Electronically controlled
dispersion measurement turntable
 The ”ET
Commander”
control panel
gives a complete
display of all the
functions
available on ET 2.
 This is the screen
seen by a user
with just one ET 2
unit connected.
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Selection of Manual or Automatic control
with “ET Commander”
Outline ET2-ST2: Electronically controlled
dispersion measurement turntable
This button shows the selection enabled: “Manual”,
“Timer”, “External” or “Internal”. Clicking on it, the “Start
Control Mode” screen appears to enable the required
option to be selected.
 Manual: manual mode
 Timer: rotation according to the interval of time
set between the ST2's movements.
 External: the turntable rotates when an external
TTL pulse is received on the “Computer Parallel
Port” connector on the ET 2's front panel.
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 Internal: the turntable is rotated by a TTL pulse
received on the PC's parallel port.
Outline ET2-ST2: Electronically controlled
dispersion measurement turntable
Manual control with “ET Commander”
The ”ET Commander” control panel give a complete display of all the functions
available on ET 2.

This part displays ST2's position (in
degrees) and the two LEDs indicate
the direction of movement.
 A Manual movement is set
here: pressing “Start”, the
turntable carries out a
movement equal to the
degrees selected.
 Pressing this button returns
the turntable to the Zero (0°)
position.
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
This button runs a
turntable status
test.
Automatic control via “ET Commander”
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 The “step” for the complete rotation in
Automatic mode is set here: when “Start” is
pressed, the turntable rotates through 360°
with the selected steps.
Outline ET2-ST2: Electronically controlled
dispersion measurement turntable
 The Macros are set here by keying in the
(negative or positive) "step" for rotation
in automatic mode.
 One of the 10 letters available (from A to
J) is selected, the required angle is set
with the arrows and confirmed by
clicking the “Insert” button.
 Pressing “Start” starts the macro
sequence run from “A” to the last letter
set: the ST 2 turntable carries out a
movement equal to the angular step set.
 For example, it's possible to set a 10°
step on A, 340° on B: in this case, ST 2
moves in a clockwise direction from 0°
to 10°, then goes back to the 340°
position (-10°).
 The command varies according to what
has been set with the “Start Mode”
button.
Control of 2 ET 2 units via “ET Commander”
Outline ET2-ST2: Electronically controlled
dispersion measurement turntable
The Outline “ET Commander” program can control up to TWO ET 2 units, driving two
ST2 (*) turntables, which can therefore rotate separately and freely (plus other two
“slave” turntables).
 This is the screen
seen by users with
two ET 2 units
connected to an ET
Commander.
 The On/Off buttons
for units A and B are
used to enable or
disable them.
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 When the button is
clicked, the writing
on it changes from
“On” to “Off” and
vice versa.
Examples of use of the Outline “E.T.” system
Outline ET2-ST2: Electronically controlled
dispersion measurement turntable
The “E.T.” system has been designed and built to carry out polar response
measurements on loudspeaker systems, but can also be efficiently used for all
applications requiring a sophisticated computer-controlled turntable system.
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Example 1: Polar measurements - 1 axis – 2D
This system allows to obtain 2D Polar plots
(just one axis per set of measurements)
Example of 2D Polar Plot obtained with LinearX LMS4®
Other Polar Plots
with different
appearances but the
same results can be
obtained with the
following
measurement
systems (among the
best known):
 DRA MLSSA®
 Techron TEF 20®
 Audiomatica Clio®
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Outline ET2-ST2: Electronically controlled
dispersion measurement turntable
Outline ET2-ST2: Electronically controlled
dispersion measurement turntable
Setup for Polar measurements - 1 axis: example of hardware
As well as the Outline
“ET 2 – ST 2” set, the
following are required:
System under
measurement
ST 2


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One stand with
adjustable
height regolabile
One adjustable
microphone
stand
Microphone
Adjustable stand
Adjustable stand
Polar measurements:
1 axis – Horizontal plane of the speaker enclosure
In this way, the polar
response of the speaker
enclosure on the
horizontal plane is
obtained:
 Position the speaker
enclosure's acoustic
emission centre on the
axis of rotation of the ST 2
and the measurement
microphone
perpendicular to the
speaker enclosure's
acoustic centre.
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 Carry out a set of SPL
response measurements
until the required rotation
is achieved.
Outline ET2-ST2: Electronically controlled
dispersion measurement turntable
Polar Measurements:
1 axis – Vertical plane of the speaker enclosure
In this way, the polar
response of the speaker
enclosure on the vertical
plane is obtained:
 Carry out the same
procedure as for “1
horizontal axis”
measurement, with the
speaker enclosure
turned through 90° on
its emission axis.
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Outline ET2-ST2: Electronically controlled
dispersion measurement turntable
Example 2: Polar Measurements – 2 axes – 3D
Outline ET2-ST2: Electronically controlled
dispersion measurement turntable
This system enables 3D polar plots to be obtained (two axes per set of measurements)
in the shortest possible time and taking the smallest number of measurements.
 Using two ST 2
turntables (one rotating
the speaker enclosure
and the other the
microphone), it's
possible to obtain
measurements for
drawing up 3D Polar
Plots.
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 With “n” rotations of
360° of the speaker
enclosure equal to “n”
movements of the
microphone from 0° to
90°, a 3D polar plot
relative to a hemisphere
(2p steradians) can be
obtained.
Outline ET2-ST2: Electronically controlled
dispersion measurement turntable
Setup for Polar M. – 2 axes – 3D: Hardware example for speaker enclosure
By means of dedicated simple hardware (built “ad hoc”), such as that shown in this
example, any type of speaker enclosure can be positioned, maintaining the emission
axis perpendicular to the centre of rotation.
 The lower circular section, which serves as a rotation support for the arms, is bolted to the
bottom of the ST 2 and will in turn be fixed (for example) to the walkway grating of an
anechoic chamber, or simply place on an absorbent floor for the measurements in 2p str.
 The arms shown
here, which can be
freely moved, are
bolted to the top
holes of the ST 2
 The components
shown can be built
using normal steel
tubing, easily
found anywhere.
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Outline ET2-ST2: Electronically controlled
dispersion measurement turntable
Setup for Polar M. – 2 axes – 3D: Hardware example for microphone.
Example of dedicated hardware for the second ST 2 base for rotating a microphone.
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Outline ET2-ST2: Electronically controlled
dispersion measurement turntable
Setup for Polar M. – 2 axes – 3D: Example of set-up in an anechoic chamber
Example of a set-up in an anechoic chamber for a system with two ET 2 and two ST 2
turntables: to carry out this type of measurement, the speaker enclosure must be
positioned with its horizontal emission axis turned through 90°, i.e. laid on its side.
 The
component being measured in this case is the top horn of the speaker
enclosure, whose emission axis is perpendicular to the axis of rotation and
coincides with that of the microphone.
Second ST 2
Grilled
Grilled flooring
flooring
Anechoic cones
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If a
measuremen
t in 2p ster.
has to be
carried out,
it's
obviously
possible to
repeat the
same
“sketch” in a
free field
with the
system laid
on the floor.
All supports will
be covered with
soundproofing
material to
avoid
reflections
Microphone
First ST 2
Polar Measurements – 2 axes – 3D: Step 1
First measurement on the chosen emission axis:
speaker enclosure and microphone both positioned at 0°

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The microphone
remains
positioned at 0°
while the speaker
enclosure carries
out a complete
rotation (355°)
with 5° steps (or
multiples thereof).
Outline ET2-ST2: Electronically controlled
dispersion measurement turntable
Polar Measurements – 2 axes – 3D: Step 2
Outline ET2-ST2: Electronically controlled
dispersion measurement turntable
The speaker enclosure carries out a complete rotation for each microphone angulation:
here it has already carried out a rotation of 330° with 5° steps, whereas the
microphone remains positioned at 0°.

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The last
measurement at 0°
on the Horizontal
axis finishes with
the speaker
enclosure
positioned at 355°
(if a 5° step is
selected).
 When the speaker
enclosure returns
to position 0°, the
microphone turns
through 5°
(clockwise) and the
measurement
sequence starts
again with a
second complete
rotation.
Measurements Polar – 2 axes – 3D: Step 3
Outline ET2-ST2: Electronically controlled
dispersion measurement turntable
In this example, the speaker enclosure has already carried out two complete rotations
(in 5° steps) and is in position 330°, whereas the microphone has moved 5° three
times.

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The last
measurement for
preparing a 3D
polar plot is taken
when the
microphone is in
the vertical
position (90°) and
the speaker
enclosure has
reached position
355°.
Outline ET2-ST2: Electronically controlled
dispersion measurement turntable
Polar measurements – 2 axes – 3D: result
The polar plot of the complete sphere can be prepared by using the measurement
system software to calculate a “Mirror” of the hemisphere obtained.
Every computerized
measurement system
generally has its own
programming language.
The routine for carrying
out the necessary
calculation will be
prepared using this
language.
Mirror
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It is however possible to create a simple
data conversion program, no matter what
the measurement system.
Outline ET2-ST2: Electronically controlled
dispersion measurement turntable
Example 3: Polar measurements of microphones
This system can be used to prepare a 2D polar plot of a microphone.
Grilled flooring
Anechoic cones
 With additional
equipment (to rotate
the microphone on
the other plane) and
suitable
interpolation
software, a 3D plot
can be prepared.
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 According to the type of microphone being measured, its
acoustic centre (the capsule) will be perpendicular to or
coincident with the ST2 turntable's rotation axis.
Outline ET2-ST2: Electronically controlled
dispersion measurement turntable
Example 4: Using ET 2 with two ST 2 for listening to music
Taking advantage of the possibility of controlling two ST 2 (one of which is counterrotating), tests can be run to find the best stereo image.

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For example, Hi-Fi stores continually carrying out demos of
various types of loudspeakers enclosures can experiment
directly from the comfort of a demo room chair, and hear (in
real time) the change that take place in the stereo image when
the loudspeaker enclosures' reciprocal angle is changed.
Example 4 - Enclosures in position 0°

Outline ET2-ST2: Electronically controlled
dispersion measurement turntable
The emission axes of the two enclosures are perpendicular to the plane of the
listening point.
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Example 4 - Enclosures in position X1
Outline ET2-ST2: Electronically controlled
dispersion measurement turntable
The emission axis of speaker “L” is rotated by –(X°) in relation to the listening point.
 The emission axis of speaker “R” is rotated by +(X°) in relation to the listening
point.

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Example 4 - Enclosures in position X2
Outline ET2-ST2: Electronically controlled
dispersion measurement turntable
Loudspeaker enclosure's “L”'s emission axis is now rotated by –(X1°+X°).
 Loudspeaker enclosure “R”'s emission axis is now rotated by +(X1°+X°).


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With ET Commander,
the movement of the
two turntables can be
freely inverted
(however, one of them is
always a “slave”).
Outline “E.T.” System
Outline ET2-ST2: Electronically controlled
dispersion measurement turntable
USA Distributor:
Old Colony Sound Laboratories (Audio Amateur Group)
Some references:
 AKG Acoustics - Austria
 KRELL Industries – USA
 AUDIOMATICA – Italy
 LinearX Systems – USA
 AURA Systems – USA
 LUCASFILM THX – USA
 BOSE Corporation – USA
 MACKIE Designs – USA
 CARVER Corporation – USA
 MILLER & KREISEL – USA
 CELESTION – England
 MUNRO Associates – England
 CHALMERS University of Technology – Sweden  NEXO – France
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 COMMUNITY Professional – USA
 NOKIA Research Center
 CROWN International – USA
 PEAVEY Electronics – USA
 DRA Labs – USA
 PIONEER Electronics – USA
 EVI Audio – Germany
 RCF - Italy
 GENELEC – Finland
 ROCKFORD Acoustic – USA
 HARMAN Motive – USA
 SAN JOSE’ State University - USA
 HELSINKY University of Technology- Finland
 SIEMENS Hearing Instruments – USA
 KEF – England
 STAGE ACCOMPANY - Holland
 INFINITY Systems – USA
 Synergetic Audio Concepts – USA
 KLIPSCH Professional
 TURBOSOUND – England
Outline ET2-ST2: Electronically controlled
dispersion measurement turntable
Technical specifications of the Outline “E.T.” System
 Power requirements: 110/220 VCA 50/60Hz mains socket with fuse and voltage changer.
 12/20 VCC XLR connectors; internal short-circuit and inverted polarity protection circuit
 Max rotation speed: 200 msec/degree
 Precision: ± 0.25°
 Control system: optical position sensor
 Input/output connectors: 9-pole sockets (DB9)
 Input pulse: TTL (from 5 to 12 VCC) imp. 680 Ohms
 Output pulse: TTL with delay variable from 3 to 25sec.
 Pulse length 0.5 sec.
 Rotation angle: variable from 2.5° to 22.5° in minimum 2.5° steps
 Automatic reset button
 ST 2 maximum load admitted: stacked 300kg., appended 100 Kg., twisting moment 30 Kg.
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 ET 2 dimensions: 1 x 19” E.I.A. unit standard Rack x 125mm. depth
 ST 2 dimensions: diameter 35 cm. - height 10 cm.
Thanks
for
the attention