SPL Phonitor 2730 User manual

Manual
Phonitor
Headphone Monitoring Amplifier
Model 2730
1
5
°
2
2
°
3
0
°
4
0
°
5
5
°
7
5
°
-
2
.
0
-
1
.
6
-
1
.
2
-
0
.
9
-
0
.
6
-
0
.
3
d
B
C
E
N
T
E
R
L
E
V
E
L
OFF ON OFF ON
METER CAL.
METER MODE
VU PPM
+60
-2 0
MONO
CROS./SPK. CENTER
OFF ON OFF
SOLO
L R
OFF
Ø
L R
OFF
S
P
E
A
K
E
R
A
N
G
L
E
C
R
O
S
S
F
E
E
D
M
I
N
2
3
4
5
M
A
X
DIM
120 V Rail Headphone
Monitoring Amplifier
Phonitor
Model 2730
V
O
L
U
M
E

2Phonitor
Manual Phonitor Model 2730
Version 1.0 – 5/2008
Designer: Wolfgang Neumann, Hermann Gier
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 document.
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 reproduced in any manner, in part or fully, without prior authorization by SPL.
SPL electronics GmbH, Sohlweg 80, 41372 Niederkruechten, Germany
Phone. [phone]
Fax [phone]
E-Mail: [e-mail]
Internet: www.soundperformancelab.com, www.spl-usa.com
CE Declaration of Conformity
Manufacturer: SPL electronics GmbH, Type of Equipment: Audio Signal
Processor, Product: Phonitor, Model 2730, Compliance Engineer:
Wolfgang Neumann
Test Basis: EN50081-1:1992, EN50082-1:1992, EN60065:1993, EN61000-3-3:1995,
EN60065:2002, EN55013:2001, EN55020:2002, EN61000-3-2:2000, 73/23 EWG;
93/68 EWG. We herewith declare, that the construction of the Phonitor, Model
2730, is in compliance with the standards and regulations mentioned above.
Notes on Environmental Protection
At the end of its operating life, this product must not be disposed of
with regular household waste but must be returned to a collection
point for the recycling of electrical and electronic equipment. The
“wheelie bin“ symbol on the product, user‘s manual and packag-
ing indicates that. The materials can be re-used in accordance with their mark-
ings. Through re-use, recycling of raw materials, or other forms of recycling of
old products, you are making an important contribution to the protection of our
environment. Your local administrative office can advise you of the responsible
waste disposal point.
WEEE Registration: 973 349 88
© 2008 SPL electronics GmbH. All rights reserved. Names of other companies
and their products are trademarks of their respective owners.

Phonitor 3
Symbols And Notes, Scope of Delivery ............................. 4
Important Security Information ..................................... 5
Hook Up .............................................................. 7
Introduction .......................................................... 8
Applications ....................................................... 9
A New Kind Of Headphone Amplifiers:
Headphone Monitoring Amplifiers ............................... 9
With And Without Magnifiers .................................... 9
The End Of Ear Fatigue ............................................ 10
Rear Panel/Connections ............................................ 12
Wiring .............................................................. 12
Voltage, Power Connection, Power, XLR Connectors . . . . .... . . . . 13
Pin Wiring XLR Connectors, GND Lift Switch ..... . . . . ..... . . . . ... 14
Front Panel/Connection ............................................. 15
Headphone Connection, Recommendations, Warning . ..... . . . . 15
Control Elements .................................................... 16
Crossfeed, Speaker Angle ........................................ 16
Interaural Level and Time Differences
as Related to Crossfeed Setup .... . . . . . .... . . . . . .... . . . . . .... . . . . 17
Interaural Level and Time Differences
as Related to Speaker Angle Setup ....... . . . . . .... . . . . . .... . . . . . 18
Table: Crossfeed and Speaker Angle Parameters . . ..... . . . . . ... 19
CROS./SPK., Center Level, Center Off/On . . . . .... . . . . . .... . . . . . .. 20
VU Meter, Signal LED, Overload LED ... . . . . . ..... . . . . ..... . . . . ... 21
Meter Mode, Meter Cal., Dim ..................................... 22
Solo, Phase Ø ..................................................... 23
Mono, Volume .................................................... 24
OPERATION: Quick Guide to Headphone Monitoring ........... 25
Adjust Headphone Reproduction to Loudspeaker Monitoring ... 25
Specifications ....................................................... 28
Measurements ...................................................... 29
Frequency Response, Phase Response . . . . . . .... . . . . . .... . . . . . .. 29
THD vs. Output Level, THD vs. Frequency .. . . . . . .... . . . . . .... . . . . 30
Copy Master: Recall Settings ....................................... 31
Guarantee ............................................................ 32
Contents

4Phonitor
Symbols and Notes
Scope Of Delivery
Symbols And Notes
IN THIS MANUAL A LIGHTNING SYMBOL WITHIN A TRIANGLE WARNS
YOU ABOUT THE POTENTIAL FOR DANGEROUS ELECTRICAL SHOCKS
– WHICH CAN ALSO OCCUR EVEN AFTER THE MACHINE HAS BEEN
DISCONNECTED FROM A POWER SOURCE.
AN EXCLAMATION MARK (!) WITHIN A TRIANGLE IS INTENDED TO MAKE
YOU AWARE OF IMPORTANT OPERATIONAL ADVICE AND/OR WARNINGS
THAT MUST BE FOLLOWED. BE ESPECIALLY ATTENTIVE TO THESE AND
ALWAYS FOLLOW THE ADVICE THEY GIVE.
The symbol of a lamp directs your attention to explanations of impor-
tant functions or applications.
Attention
Do not attempt any alterations to this machine without the approval
or supervision of SPL electronics GmbH. Doing so could nullify com-
pletely any and all of your warranty/guarantee rights and claims to
user support.
• Phonitor, Model 2730
• This manual
• Power cord

Phonitor 5
Important Security Information
Please note and retain this manual. Carefully read and follow all of the
safety and operating instructions before you use the machine. Be dou-
bly careful to follow all warnings and special safety instructions noted
in this manual and on the unit.
Connections: Only use the connections as described. Other connec-
tions can lead to health risks and equipment damage.
Water And Humidity: Do NOT use this machine anywhere near water
(for example near a wash basin or bath, in a damp cellar, near swim-
ming pools, or the like). In such cases there is an extremely high risk of
fatal electrical shocks!
Insertion Of Foreign Objects Or Fluids: NEVER allow a foreign object
through any of the machine‘s chassis openings. You can easily come
into contact with dangerous voltage or cause a damaging short circuit.
NEVER allow any fluids to be spilled or sprayed on the machine. Such
actions can lead to dangerous electrical shocks or fire!
Opening the Machine: Do NOT open the machine housing, as there is
great risk you will damage the machine, or – even after being discon-
nected – you may receive a dangerous electrical shock!
Electrical Power: Run this machine ONLY from sources which can
provide proper power at the prescribed rating. When in doubt about
a source, contact your dealer or a professional electrician. To be sure
you have isolated the machine, do so by disconnecting the power cord
from your wall connection. Be sure that the power cord plug is always
accessible. When not using the machine for a longer period, make sure
to unplug it from your wall power socket.
Power Cord Protection: Make sure that your power cord is arranged
to avoid being stepped on or any kind of crimping and damage related
to such event. Do not allow any equipment or furniture to crimp this
power cord.
Power Connection Overloads: Avoid any kind of overload in connec-
tions to wall sockets, extension or splitter power cords. Always keep
manufacturer warnings and instructions in mind. Overloads create fire
hazards and risk of dangerous shocks!
Lightning: Before thunderstorms or other severe weather, disconnect
the machine from wall power (but to avoid life threatening lightning
strikes, not during a storm). Similarly, before any severe weather, dis-
connect ALL the power connections of other machines and antenna and
phone/network cables which may be interconnected so that no light-
ning damage or overload results from such secondary connections.

6Phonitor
Air Circulation: Chassis openings offer ventilation and serve to protect
the machine from overheating. NEVER cover or otherwise close off
these openings. NEVER place the machine on a soft surface (carpet,
sofa, etc.). Make sure to provide for a mounting space of 4-5 cm/2 inch-
es when mounting the machine in racks or cabinets.
Controls And Switches: Operate the controls and switches only as
described in the manual. Incorrect adjustments outside safe para-
meters can lead to damage and unnecessary repair costs. Never use
the switches or level controls to effect excessive or extreme changes.
Repairs: Unplug the machine and immediately contact a qualified
technician when you think repairs are needed – or when moisture or
foreign objects may accidentally have gotten in to the housing, or in
cases when the machine may have fallen and shows any sign of hav-
ing been damaged. This also applies to any situation in which the ma-
chine has not been subjected to any of these unusual circumstances
but still is not functioning normally or its performance is substantially
altered.
In cases of damage to the power cord or its plug, first consider turning
off the main circuit breaker before unplugging the power cord.
Replacement/Substitute Parts: Be sure that any service technician
uses original replacement parts or those with identical specifications
as the originals. Incorrectly substituted parts can lead to fire, electrical
shock, or other dangers, including further equipment damage.
Safety Inspection: Be sure always to ask a service technician to con-
duct a thorough safety check and ensure that the state of the repaired
machine is in all respects up to factory standards.
Cleaning: In cleaning, do NOT use any solvents, as these can damage
the chassis finish. Use a clean, dry cloth (if necessary, with an acid-free
cleaning oil). Disconnect the machine from your power source before
cleaning.
Important Security Information

Phonitor 7
Be very careful to check that the rear chassis power selection switch
is set to the correct local line voltage position before using the unit
(230 V position: 220-240 V/50 Hz, 115 V position: 110-120 V/60 Hz)!
When in doubt about a source, contact your dealer or a professional
electrician.
Before connecting any equipment make sure that any machine to be
connected is turned off. Follow all safety instructions from page 5.
Place the unit on a level and stable surface. The unit’s enclosure is EMC-
safe and effectively shielded against HF interference. Nonetheless, you
should carefully consider where you place the unit to avoid electrical
disturbances. It should be positioned so that you can easily reach it,
but there are other considerations. Try not to place it near heat sources
or in direct sunlight, and avoid exposure to vibrations, dust, heat, cold
or moisture. It should also be kept away from transformers, motors,
power amplifiers and digital processors. Always ensure sufficient air
circulation by keeping a distance of 4-5 cm/2 inches to other units and
to the sides of the unit.
Before You Begin
Make sure the Volume control is turned hard left before you power up
the unit. Now control Volume. Note that too high levels can damage
headphones and hearing!
Hook Up

8Phonitor
Introduction
There is more than meets the eye in working with headphones. A rea-
son for this surely lies in that modern audio production often neces-
sitates decentralized processes. In turn, production phases following
such plans more often take place in acoustically questionable rooms.
In such circumstances, a mix might occur in an acoustically deficient
ambiance (for example, in an extremely modal room), and employing
headphones then begins to make sense when a successful mix would
otherwise turn out to be impossible.
But another fact is that many musicians or producers might wish to – or
be able to – mix at home (to say nothing of having to). Then the head-
phone becomes a clear must, enabling an evening or late night session
that can only take place thanks to its being unhindered by the local
acoustic environment.
Each and every careful headphone user should know about the ana-
lytical advantages of headphone monitoring, but also about the main
disadvantage: the difficulty (if note impossibility) in properly judging
room ambiance.
Therefore, several years ago SPL began planning the development of
a compact, professional headphone amplifier design based on its 120
volt technology. The essential inspiration came from project manager
Hermann Gier‘s desire to eliminate the major disadvantage in working
with headphones. It therefore meant transferring essential ambient
parameters of loudspeaker monitoring to the headphone monitoring.
After several years of development and painstaking optimization, we
can now introduce the Phonitor, whose derivative name from combin-
ing “Headphone“ and “Monitor“, conveys the successful conclusion of
this process.
At first glance the Phonitor‘s functional range makes immediately
clear that this is not just another headphone amplifier. With the usual
(monitoring) parameters there are new functions such as “Crossfeed“,
“Speaker Angle“ and “Center Level“. These are the essential parame-
ters to create what with loudspeaker monitors are perception of width,
balance and overall space and how we recognize them coming from
the loudspeaker. Crossfeed simulates the frequency dependent inter-
aural level differences from both channels. Speaker Angle determines
the stereo width caused by frequency dependent interaural time dif-
ferences. Center Level regulates the balance between phantom center
and L/R stereo signals.

Phonitor 9
Applications
Aside from its outstanding abilities as loudspeaker substitute the
Phonitor offers well equipped studios a fully functional monitoring
alternative.
In addition one can take along the Phonitor into an unfamiliar studio
or production environment that always provides the engineer’s own
monitor sound.
Furthermore, with the Phonitor one can simply enjoy music as it was
originally mixed, namely for playback over loudspeakers.
A New Kind Of Headphone Amplifiers:
The Headphone Monitoring Amplifiers
The Phonitor design is our high-end interpretation for what a complete
headphone amplifier should be. A well chosen system of Phonitor and
headphones can by and large replace loudspeakers and offers best
requirements for a fatigue-free hearing and successful work sessions.
We therefore refer to the Phonitor as a headphone monitoring amplifier
system.
The basis for this high-end development is our proved 120 volts ref-
erence technology based upon our own, handmade operation ampli-
fier. It corresponds to approximately twice that of most modern analog
audio semiconductor technologies. Through such 120 volts circuitry
and processing we reach performance levels far beyond conventional
designs in dynamic range and distortion levels.
Such technical specifications exceed all known analog or digital stan-
dards (please also refer to the chapter “The End of Ear Fatigue” from
page 10).
With And Without Magnifiers
The Phonitor encompasses advantages of both kinds of monitoring
methods: On one hand the analytical headphone monitoring is like
working with an acoustic magnifier but without external room influenc-
es; on the other hand, loudspeaker monitoring forgoes the microscopic
effect, but provides for room ambiance.
Working with the magnifier effect of headphones has the advantage of
safely hearing clicks or similar defects and helps in fine tuning cross-
fades or to judge tonal problems in individual tracks. >
Introduction

10 Phonitor
With And Without Magniers, The End Of Ear Fatigue
Introduction
On loudspeakers such analyses are much more difficult, as such prob-
lems just are not as apparent when one is working without being able
to “zoom in” aurally.
Conversely, loudspeakers provide monitoring with the advantage of
spatial balance in a (definable through placement) stereo width, which
in turn provides the illusion of an acoustic stage.
Traditional headphone reproduction produces one 180-degree stereo
width in the middle of the head, and it is exactly this which creates the
very problematic-to-impossible headphone mixing environment. An es-
sential reason for such unnatural ambiance is the complete separation
of the channels, which does not exist either in natural hearing or in ste-
reo loudspeaker reproduction. This makes it nearly impossible to judge
tonal balance, a stereo image and the phantom center level. Panorama
adjustments as well as related EQ settings that one attempts with
headphones, typically just do not function on loudspeakers.
Moreover, what is often called the “super stereo effect” with head-
phones usually creates a great deal of ear fatigue in the long run. Over
loudspeakers the sound stage is felt in front, while in contrast, when
monitoring through headphones, the stage is present on the left and
on the right – but frontal and rear information is lost.
The End Of Ear Fatigue
Aside from these unnatural headphone ambiance there are further dis-
advantages with fatigue when mixing or listening with headphones.
First, some cans themselves may not be that comfortable to wear...
Moreover, a standard headphone amplifier is often an additional im-
portant reason for premature ear fatigue. Almost without exception,
present-day headphone amplifiers employ comparatively undemand-
ing IC’s. In the best cases they might work with symmetrical voltages of
+/-15 V to +/-18 V, and in less favorable cases, with only a simple supply
of 9 or 12 V from cheaper external “wall-wart“ power supplies.
But the voltage level acts in circuitry much like the cubic inch capacity
to the productive power of a combustion engine: Cubic inch capacity is
replaceable with nothing but more cubic inch capacity – and in the pro-
ductive power of electronics, voltage level functions similarly.

Phonitor 11
The End Of Ear Fatigue Introduction
For some years, now, SPL has addressed this issue in all of its master-
ing product series through its own specifically developed 120 volt tech-
nology. Consoles and signal processors of the SPL Mastering Series
appear as central elements in installations of today’s most renowned
mastering houses (z. B. Bob Ludwig’s Gateway Mastering & DVD in the
USA, Simon Heyworth’s Super Audio Mastering in Great Britain or the
Galaxy Studios in Belgium).
This 120 volt technology is based on discrete operation amplifiers
from SPL’s own production, developed and perfected over many years
by SPL’s co-founder and chief developer, Wolfgang Neumann. These
SUPRA OPs work with high-performance semiconductors in Class A
technology at a symmetrical voltage of +/-60V.
In the Phonitor nine SUPRA OPs are employed. The SUPRA OPs have a
Signal To Noise Ratio of 116 dB and offer a nearly 34 dB headroom – that
yields an unequalled 150 dB dynamic range.
The musical result is not to be mistaken: Regardless of the monitor-
ing means, regardless of how loud you monitor – the Phonitor always
remains a distant, impartial factor unaffected when used to capacity
and beyond being overloaded. The phase stability is always perfect,
its THD next to immeasurable. The Phonitor’s SUPRA OPs cannot be
stressed in the most stressful circumstances, and for precisely this
reason its musical sound is always relaxed and spacious. All frequen-
cies are reproduced in balance, basses are stable and tight, mids are
clear and differentiated and highs remain transparent and soft.
Such supreme and heretofore unreachable neutrality in audio repro-
duction is the direct consequence of our technical approach and basis
in 120 volt technology: Possible disturbances from such as noise or dis-
tortion are so slight that we even arrive at the boundaries of the best
measuring equipment, and what remains is quite simply unaltered mu-
sical sound.

12 Phonitor
Rear Panel/Connections Wiring
Make sure that the voltage switch setting
reflects the correct local power line voltage.
Input & Output
Right Channel
The Phonitor can be fed from any stereo signal path via its
rear panel XLR sockets. Headphone connection on the front panel.
Input & Output
Left Channel
Power Supply
Connection
Power
Switch
GND Lift
Switch

Phonitor 13
Voltage
The rear panel voltage selector switch serves to let the user switch to
the local line voltage standard.
IMPORTANT ADVICE: Before you use the Phonitor, make
sure that this switch setting reflects the correct local power
line voltage (115 V position: 110-120 volts/6o Hz, 230 V
position: 220-240 volts/50 Hz).
Power Connection
Connect the included power cord to the rear Mains Input. Transformer,
power cord and case connection conform to VDE, UL and CSA require-
ments. Power fuse ratings are 500 mA slow blow ( 220-240 volts) or 1 A
slow blow ( 110-120 volts).
Power
The rear panel Power switch activates the unit, confirmed by the light-
ed VU meters.
IMPORTANT ADVICE: Switch on the unit only after you have
turned the Volume control fully left, and wait to set your de-
sired volume level until the unit is powered on. Neglecting
this can damage either or both your ears and your headphones!
XLR Connections
Switch off the unit before you begin the process of making the first
or any subsequent connections (rear panel Power switch). Neglecting
this can damage either or both your ears and your headphones!
Connect the monitoring signal to the left and right channel XLR input
sockets. Both XLR outputs transmit the monitoring signal unaltered
so that no additional monitoring output is needed for insertion of the
Phonitor. Input and output stages are electronically balanced. They
ensure high common mode rejection and drive long cable connections
(depending on cable capacities and following input stages).
Rear Panel/Connections
Connections & Switches

14 Phonitor
Pin Wiring XLR Connectors, GND Lift
Rear Panel/Connections
Pin Wiring XLR Connectors
The diagram shows how to wire the balanced XLR connections if unbal-
anced connections are required.
GND Lift
The rear panel GND lift switch eliminates hum by separating the inter-
nal ground from the unit’s housing ground. Hum can, for example, re-
sult when this unit’s housing has a common ground connection with
other machines that might have a different ground potential.
Input Output
balanced unbalanced balanced unbalanced
1=GND
2=hot (+)
3=cold (-)
1
2
3
1
2
3
12
3
12
3

Phonitor 15
Front Panel/Connection
Headphone Connection
Headphone Connection
Connect headphones to the standard 1/4” (TRS) stereo plug on the
lower right front panel. The layout is: Tip =left channel, Ring = right
Channel, Sleeve = ground.
Make sure that the plug firmly seated for a solid connection.
Recommendations
Unplug the headphone when you switch off the Phonitor. Otherwise
discharging residual voltages can cause beeping sounds. We did not
add a circuitry to avoid that phenomenon as it would have compro-
mised sound quality.
Reduce volume level before you remove or plug in the headphone (or
when switching headphones). This excludes louder clicks and pops
reaching the ear. In addition, this can avoid unpleasant surprise that
follows when a headphone’s lower impedance suddenly reproduces an
otherwise acceptable Phonitor volume setting of a first headphone at a
much higher – even painful – level.
Warning
NEVER plug in a mono 1/4“ to the headphone output. The use of a
mono 1/4“ will lead to a short-circuit that will destroy the final ampli-
fier stage! Standard headphone connectors always have stereo plugs,
and thus a correct connection will be assured when you only connect
headphones directly.
1
5
°
2
2
°
3
0
°
4
0
°
5
5
°
7
5
°
-
2
.
0
-
1
.
6
-
1
.
2
-
0
.
9
-
0
.
6
-
0
.
3
d
B
C
E
N
T
E
R
L
E
V
E
L
OFF ON OFF ON
METER CAL.
METER MODE
VU PPM
+60
-2 0
MONO
CROS./SPK. CENTER
OFF ON OFF
SOLO
L R
OFF
Ø
L R
OFF
S
P
E
A
K
E
R
A
N
G
L
E
C
R
O
S
S
F
E
E
D
M
I
N
2
3
4
5
M
A
X
DIM
120 V Rail Headphone
Monitoring Amplifier
Phonitor
Model 2730
V
O
L
U
M
E

16 Phonitor
Crossfeed, Speaker Angle
Crossfeed
The Crossfeed switch allows you to adjust the frequency-dependent
crossfeed simulation of both channels by adjustments of interaural
level difference – as if this characteristic would be heard from moni-
tors when in their own room ambiance. One can compare variations
in crossfeed values as approximating the influence of different room
sizes and characteristics on a given loudspeaker setup.
This adjustment can be made in six steps ranging from “minimum” to
“maximum”. Crossfeed interacts with the Speaker Angle value to simu-
late the width of a stereo image (please refer to the next section).
For further information regarding simulation of a specific loudspeak-
er playback setup, please refer to the “Quick Guide To Headphone
Monitoring“ on page 25.
Speaker Angle
The Speaker Angle switch provides for frequency-dependent simula-
tion of your stereo image width by adjustments of interaural time dif-
ference. This influences the moment in time at which a signal‘s wave
form arrives at the ear and corresponds to a particular variation in the
angle of an actual loudspeaker pair.
The time constants of the interaural time differences between the left
and right channels occur within a range of 90 to 635 microseconds.
Compare the table “Crossfeed and Speaker Angle Parameters” on page
19. We recommend to start with the figures of the accentuated lines
from this mathematically-based table for a given monitoring setup. As
you might expect, however, the best results can only occur when you
follow the recommendations and then as needed, carefully engage in
your own additional fine tuning, especially between Speaker Angle and
the Crossfeed value.
For further information on the simulation of a specific loudspeaker
playback, please refer to the “Quick Guide To Headphone Monitoring“
on page 25.
Control Elements
1
5
°
2
2
°
3
0
°
4
0
°
5
5
°
7
5
°
S
P
E
A
K
E
R
A
N
G
L
E

Phonitor 17
Crossfeed, Speaker Angle
Interaural Level and Time Differences as Related
to Crossfeed Setup
The following two diagrams show, respectively (on the left), the fre-
quency response of interaural level differences and (on the right)
the interaural time difference at maximum Crossfeed value and at a
Speaker Angle of 30 degrees.
The following two diagrams show, respectively (on the left), the fre-
quency response of the interaural level difference and (on the right) the
interaural time difference, at minimal Crossfeed value and a Speaker
Angle of 30 degrees.
The black curves stand for the side of the direct sound wave front,
while the gray curves stand for the opposite side. It is clearly recogniz-
able that corrections are usually done for frequencies below 1 kHz.
You should also note that the Crossfeed control functions mainly level
dependent. Effects with respect to time differences are comparatively
slight. However, that they, too, may be altered is an indicator of interac-
tion between Crossfeed and Speaker Angle control.
Control Elements

18 Phonitor
Control Elements
Interaural Level and Time Differences as Related
to Speaker Angle Setup
The following two diagrams show (on the left) the frequency response
of interaural level difference with respect to the interaural time differ-
ence (on the right) at maximum Crossfeed value and a Speaker Angle
of 75 degrees.
The following two diagrams show, respectively (on the left), the fre-
quency response of the interaural level difference and the interaural
time difference (on the right) at a maximum Crossfeed value and a
Speaker Angle of 15 degrees.
The black curves stand for the side of the direct sound wave front,
while the gray curves stand for the opposite side.
The larger the Speaker Angle value (and/or angle of an actual loud-
speaker placement), the greater the effect will be of shifting the oppo-
site side toward more deeply lying frequencies, since with an increased
spatial arc around the head only lower frequencies will undergo pro-
portionate modification.
It should also become apparent that the Speaker Angle control is pri-
marily depending on interaural time differences. Its influences on level
differences are in contrast, comparatively slight.
Crossfeed, Speaker Angle

Phonitor 19
Crossfeed, Speaker Angle Control Elements
Crossfeed and Speaker Angle Parameters
The accentuated lines show at which Crossfeed values the Speaker
Angle most precisely matches the theoretically determined time differ-
ence values. These, of course, are mainly a starting point to reproduce a
real monitoring setup.
Formulae for calculations from http://www.sengpielaudio.com/
LaufzeitdifferenzenBeimNatuerlichenHoeren.pdf
Speaker Angle
Switch
Crossfeed
Switch
Level
Difference
Time Diff.
(µs)
Speaker Angle
(Result)

20 Phonitor
CROS./SPK., Center Level, Center Off/On
Control Elements
CROS./SPK.
With CROS/SPK. you switch on or off Crossfeed and Speaker Angle
functions globally. This provides for direct A/B comparisons.
Your impression may at first be that the results are not so spectacular
as expected – until you consider that the Phonitor is not an effects ma-
chine. Instead, reevaluate your aural impression by thinking about this:
normal headphone monitoring confronts you with a 180-degree sound
stage – the “super stereo width” has so little to do with loudspeaker
playback. Now you can gradually reduce this in 15 degree steps with
the Speaker Angle switch. Subsequently, using the Crossfeed function,
you can simulate the acoustic effect of room size and ambient charac-
teristics on a given listening device.
Center Level
With the Center Level control you may regulate the intensity of center
signals to compensate for the stereo signal processing with Crossfeed
and Speaker Angle.
This Center Level signal is produced as a mono sum of the left and right
channels. Changes in these values are regulated through a finely gradu-
ated, six steps switch (0,3, 0,6, 0,9, 1,2, 1,6 and 2 dB).
In a normal headphone listening experience, the center signal is typically
quieter than the stereo signals, which appear much louder due to the
super stereo effect. If the signal width is narrowed through changes in
Crossfeed and Speaker Angle (so as to correspond to your actual loud-
speaker setup), the headphone center may likely sound too intense now.
Lowering the center levels will again return the center signal to the cor-
rect volume in relation to the L/R stereo image.
Center Off/On
This switch activates or deactivates the Phonitor Center Level cir-
cuitry. In conjunction with both CROS./SPK. Off/On and CENTER Off/
On switches, it offers the choice between (conventional) headphone
amplifier setup and the Phonitor’s unique headphone monitoring am-
plifier setup.
-
2
.
0
-
1
.
6
-
1
.
2
-
0
.
9
-
0
.
6
-
0
.
3
d
B
C
E
N
T
E
R
L
E
V
E
L