Neumann KH 750 DSP User manual

   ·  .  ·   · 
 ()/- ·  - · @. · ..
KH 750 DSP
A S
 . / . B M™
. /
I M

KH 750 DSP | 2
The KH 750 DSP subwoofer .................................................3
Delivery includes ..........................................................3
About this manual..........................................................3
Product overview ..........................................................4
Installing and connecting the KH 750 DSP ....................................6
Preparing the subwoofer ...............................................6
Preparing the room....................................................7
Setting up the subwoofers..............................................7
Positioning the subwoofers.............................................8
Connecting the subwoofer..............................................9
Connecting network cables . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
Connecting/disconnecting the subwoofer to/from the mains power supply ...15
Configuring and using the KH 750 DSP ......................................15
Switching the subwoofer on/o ........................................15
Functionality of the back panel lights ...................................16
AUTO STANDBY switch ................................................17
CONTROL MODE switch ...............................................17
Resetting the KH 750 DSP .............................................17
Firmware update.....................................................17
Calibrating the subwoofer.............................................18
Compensating for larger time of flight (TOF) dierences ..................20
Using the bass management ...........................................20
Remote-controlling the bass management ...............................21
Setting the replay level of the subwoofer................................21
Activating ground lift .................................................22
Cleaning and maintaining the subwoofer.....................................22
Troubleshooting ..........................................................23
Specifications ............................................................24
Pin assignment of the XLR socket ...........................................24
Acoustical measurements and block diagram.................................24
Mechanical drawings ......................................................24
Trademarks ..............................................................24
Technical information & glossary ...........................................25
Contents

KH 750 DSP | 3
The KH 750 DSP subwoofer
Thank you for purchasing a Neumann subwoofer. Neumann subwoofers are designed to com-
plement Neumann’s extensive range of monitors. They can be used in music, broadcast, and
post production studios for tracking, mixing, mastering, and home recording. They can be
positioned away from a wall, next to a wall or in a corner and can be mixed freely with other
loudspeakers and subwoofers from the Neumann Studio Monitor Systems range.
The built-in 2.0 / 0.1 Bass Manager can be used in many ways as there are four routing modes
to ensure maximum flexibility when using the subwoofer - see “Uses” below. Fourth order
crossovers and flexible acoustical controls allow for seamless system integration and the bass
management function can be remotely controlled.
State-of-the-art circuitry design and the specially developed long excursion bass driver have
been used to ensure the most accurate sound reproduction possible. Neumann products are
designed for longevity so we hope you enjoy many happy years of using this product.
Uses
• Bass extension for loudspeakers
• Increasing the maximum SPL of loudspeakers
• Decreasing harmonic and intermodulation distortion of loudspeakers
• Reproducing the LFE channel
• Reproducing the “Sub” signal of a bass managed multichannel source
• Working as an extension for KH 810, KH 870 and KH 805 subwoofer systems
• Making a Plane Wave Bass Array™ system
• Improving the modal behaviour of the room due to optimal placement of the subwoofer in
the room.
Delivery includes
1 KH 750 DSP subwoofer
4 Rubber feet
1 Quick guide
1 Safety guide
Delivery also includes European, UK or US mains cables
About this manual
This operating manual describes the physical setup and autonomous operation of the
KH 750 DSP. For information about using the KH 750 DSP in a network please refer to the very
helpful Neumann.Control software.
Some of the advantages of exploring Neumann.Control are:
• More extensive acoustical controls for more accurate audio reproduction
• System-wide control such as volume control, soloing and muting
• Rapid system re-purposing
When released, to download the app for Android or iOS tablets go to the Google Play Store or
Apple App Store and search for “Neumann.Control”.
When released, to download the software for PC or Mac go to www.neumann.com and find the
download section in the KH 750 DSP product page.
The current operating manual as well as the quick guide and the safety guide can also be
downloaded from the “Downloads” area on the product page at www.neumann.com.
Note that imperial dimensions are approximate.

KH 750 DSP | 4
Product overview
1
2
1 Neumann logo
2 Metal grille

KH 750 DSP | 5
E
B
C
A
D
3
4
89 67 5
HIJ
F
G
0
3 MAINS POWER switch
4 IEC mains socket with protective ground contact
5 LOW CUT potentiometer
6 INPUT GROUND LIFT switch
7 ETHERNET CONTROL NETWORK socket
8 XLR3-M sockets
ANALOG OUTPUT | LEFT/A
ANALOG OUTPUT | RIGHT/B
9 XLR3-F sockets
ANALOG INPUT | LEFT/A
ANALOG INPUT | RIGHT/B
0 BNC sockets
DIGITAL | AES3 INPUT
DIGITAL | AES3 OUTPUT
A SUBWOOFER GAIN | OUTPUT LEVEL switch
B SUBWOOFER GAIN | INPUT GAIN potentiometer
C SUBWOOFER PHASE switch
D SUBWOOFER PHASE switch
E BASS MANAGEMENT switch
F BASS MANAGEMENT LED
• green = active
G AUTO STANDBY switch
H POWER ON LED
• green = on
• red = protection active
• amber = indication
I CONTROL MODE switch
J CHANNEL B INPUT MODE switch

KH 750 DSP | 6
Installing and connecting the KH 750 DSP
Have the product installed and connected by a specialist. Due to his/her technical training,
know-how and experience as well as knowledge of relevant provisions, regulations and stan-
dards, the specialist must be able to assess assigned tasks, recognize potential hazards and
ensure appropriate safety measures. The following safety and mounting instructions are
addressed to this specialist.
CAUTION
Danger of injury and material damage due to tipping/dropping of the product!
If improperly mounted, the product and/or the mounting hardware (e.g. rack) can tip over
or drop down.
X
Always have the product mounted by a qualified specialist according to local, national
and international regulations and standards.
X
Use the mounting systems recommended by Neumann and always provide sucient addi-
tional protection against tipping or dropping by means of safety wires.
CAUTION
Damage to the product due to overheating!
If air cannot circulate properly around the rear of the subwoofer, the power amplifiers may
overheat leading to premature activation of the thermal protection system which limits the
maximum output level of the subwoofer. In rare cases, damage to the product may also
occur.
XThe whole of the back panel should have a free flow of air to ensure good cooling.
XWhen installing the product into tight spaces such as wall recesses, maintain an air gap
of at least 2" (5 cm) around the subwoofer’s backplate to ensure a free air flow.
For information on installation, please refer to the supplied “Getting Started Quickly”
supplement. This will help you set up the subwoofers and loudspeakers in a way that
will give you the best acoustic performance from the system. For further information on
setting up subwoofers and loudspeakers, please refer to the “Questions & Answers” sec-
tion at www.neumann.com.
Preparing the subwoofer
CAUTION
Risk of staining surfaces!
Some surfaces treated with varnish, polish or synthetics may suer from stains when they
come into contact with other synthetics. Despite a thorough testing of the synthetics used
by us, we cannot rule out the possibility of staining.
XDo not place the KH 750 DSP on delicate surfaces.
To place the subwoofer on a flat surface:
X
Attach the supplied self-adhesive feet to the bottom of the cabinet, about 2-3 cm (1") from
the edges.
This reduces the risk of scratching the surface and acoustically isolates the subwoofer from
the surface.
XAlternatively, the feet can be stuck onto the side of the cabinet if that helps with mounting
the product in the room.
If you want to hide the subwoofer:
XUse a thin open weave cloth. To provide visual cover, you can use two layers of the cloth.

KH 750 DSP | 7
Preparing the room
X
Arrange all acoustically relevant surfaces and objects symmetrically on either side of the
listening axis of the room (left/right).
XMinimize the sound that is reflected back to the listening position by using angled surfaces
and/or acoustical treatment.
X
The subwoofer can delivery very low frequencies at high levels which can lead to objects and
parts of the room structure to rattle. Ensure that rattling and resonating surfaces are avoided.
This product has been optimized for use in recording studios. In order to avoid aecting
the quality of reproduction, make sure that the product is used in an EMC environment.
Setting up the subwoofers
Choosing the type of setup
The driver is located on the front panel of the subwoofer, allowing the subwoofer to be either
set up in a room or flush mounted into a wall recess.
Flush mounting the subwoofer into a wall recess or placing it directly against the wall oers
the following advantages:
• A solid wall boosts the level of the subwoofer in the room which can be compensated by
reducing the output level of the subwoofer. This also reduces distortion resulting in a cleaner
sound reproduction.
• Reflections from the wall behind the subwoofer are eliminated so that the frequency
response becomes smoother.
• The subwoofer does not occupy space in the room when flush mounted.
If you want to flush mount the subwoofer into a wall recess:
X
Have the wall constructed by an experienced acoustical engineer. At least the following points
should be observed:
• The wall should be solid (stone, brick, concrete, several layers of gypsum or MDF).
• Ensure a free air flow around the rear of the subwoofer.
Using one or several subwoofers
XUse ...
one subwoofer several subwoofers
... if your room does not oer sucient
space for several subwoofers.
... if you need to move left and right
along the mixing console, or if there are
several listening positions along a large
format mixing console.
... if you require a higher output power
or less distortion with the same output
power.
... to suppress lateral modes or cross
modes in the room by means of a Plane
Wave Bass Array (PWBA™).
... if many smaller cabinets are easier to
position than one large cabinet.
To reduce low-frequency distortion, the uncalibrated output level of your subwoofer
should always be higher than the output level of your loudspeakers. We recommend
using arrays with several subwoofers, in which case the uncalibrated maximum output
level of the subwoofer array should also be higher than the maximum output level of all
the loudspeakers in the system. The subwoofers can then be calibrated to a lower output
level resulting in lower distortion and correspondingly cleaner low-frequency
reproduction.
For information on building a balanced system, please refer to the “Product Selection
Guide” at www.neumann.com.
The Neumann.Control software must be used to set up multiple subwoofer systems.

KH 750 DSP | 8
Positioning the subwoofers
Regardless of whether you are setting up one or several subwoofers:
X
Always ensure that the distance dwall between the wall behind the subwoofer and the sub-
woofer’s front is less than 0.8 m.
If you are setting up one subwoofer:
X
Position the subwoofer against the front wall, left or right of the middle of the front wall
ideally at 1/4 or 3/4 of the room width.
XDo not place the subwoofer at the side wall or rear wall of the room as sometimes proposed
for domestic applications.
If you are setting up several subwoofers as a Plane Wave Bass Array™(PWBA™):
XUse two to four subwoofers for smaller rooms and three to four subwoofers for larger rooms.
XSet up the subwoofers along the front wall within half a wavelength of the upper cut o fre-
quency of each other. The maximum spacing of the subwoofer cabinets is determined by the
setting of the routing mode or crossover frequency (see page 21):
Setting Max. spacing of the subwoofer cabinets
RIGHT approx. 2 m (6'6")
EXTERNAL BASS MANAGEMENT depends on crossover frequency setting in the
source equipment, for 80 Hz approx. 2 m (6'6")
LFE-MODE 1 approx. 1.4 m (4'6")
LFE-MODE 2 approx. 2 m (6'6")
If you observe the stated spacing, the subwoofers form a cylindrical source and generate
a plane wave down the room, a so-called Plane Wave Bass Array™(PWBA™). The PWBA™
reduces stationary waves between the side walls, improves the bass reproduction and
suppresses lateral room resonances.
You can correct excessive low frequency energy in the room using the potentiometer
SUBWOOFER GAIN| INPUT GAIN Band the switch SUBWOOFER GAIN | OUTPUT LEVEL A
(cf. page26).
If you set up several subwoofers, you can utilize their mutual coupling to achieve an acoustical
gain. The following acoustical gains are possible:
Number of subwoofers Acoustical gain
10.0 dB
26.0 dB
39.5 dB
412.0 dB
dwall
Utilizing the
acoustical gain

KH 750 DSP | 9
Positioning and orienting subwoofers and loudspeakers
Subwoofers are omni-directional in their typical pass band as the generated wavelength is
long compared to the surface producing the sound, therefore it does not matter in which direc-
tion the subwoofer is oriented when placed in the listening environment.
For your loudspeakers, however, an accurate positioning and orientation is vital.
XPosition your loudspeakers as follows:
System Position and orientation
2.0 (stereo) ±30°
5.1 ITU-R BS.775-1:
0°, ±30°, ±110° (±10°)
(center, front left/right, surround left/right)
ANSI/SMPTE 202M:
0°, ±22.5°, arrays to the surround left and to the surround right,
plus optional subwoofer(s)
6.1 as 5.1 systems plus 180° (back center)
7.1 0°, ±30°, ±90°, ±150°
(center, front left/right, side left/right, back left/right)
For detailed information on the positioning and orientation of your loudspeakers, please refer
to the operating manuals of the loudspeakers.
If your subwoofers cannot be placed at the same distance from the listening position as the
loudspeakers, time-of-flight dierences will occur.
XAvoid distance dierences of > 2m (6'6").
X
Compensate for time-of-flight dierences as described in the chapter “Calibrating the phase”
on page 19.
Connecting the subwoofer
Signal
(source connector) Source impedance Cable length Subwoofer connection method
Analog (RCA) low up to 10 m
(30')
via an adapter (RCA-XLR)
to the ANALOG INPUT socket (XLR)
9 (see below)
Analog (XLR) low up to 100 m
(300')
directly to the ANALOG INPUT
socket (XLR) 9 (see below)
AES3 (BNC) 75 Ω up to 100 m
(300')
directly to the DIGITAL INPUT
socket (BNC)0 (see page 10)
AES3 (XLR) 110 Ω up to 100 m
(300')
via an impedance converter and an
adapter (XLR-BNC) to the DIGITAL
INPUT socket (BNC)0(see page
10)
S/P-DIF (RCA) 75 Ω up to 10 m
(30')
via an adapter (RCA-BNC) to the
DIGITAL INPUT socket (BNC)0 (see
page 10)
The default signal selection is analog. If a valid digital signal is connected to the digital
input this digital signal is automatically selected. In Neumann.Control it is possible to select
between automatic signal switching, analog or digital.
Note: If the source equipment is digital, we recommend using digital connections from the
source to the subwoofer as this avoids additional unnecessary signal conversions.

KH 750 DSP | 10
Connecting analog signals to the KH 750 DSP
X
Use balanced XLR cables to connect the corresponding sockets ANALOG INPUT 9of the
KH 750 DSP to the audio source.
XUse an XLR adapter (not supplied) to connect unbalanced cables (e.g. RCA cables).
Use the
following wiring if you want to make your own XLR adapter:
Wiring Pin Signal
Output (RCA) Input (XLR-M)
1Audio ground
2Signal +
3Signal -
The level delivered by devices with RCA outputs (-10 dBV) is usually less than the studio
level (+4 dBu):
X
If necessary, use active unbalanced-to-balanced converters in order to be able to connect
devices with unbalanced signals.
XWe do not recommend passive unbalanced to balanced converters using transformers. They
usually limit low frequency levels and increase high frequency distortion.
Connecting digital signals to the KH 750 DSP
X
Connect the digital AES3 or S/P-DIF-output signal of your audio source to the DIGITAL INPUT
socket 0of the respective KH 750 DSP. See picture below.
The KH 750 DSP subwoofer only supports non-encoded AES3 and S/P-DIF sig-
nals. Encoded signals such as MP3, DTS or Dolby Digital are not supported.
Only one cable is needed for uncompressed AES3 and S/P-DIF digital signals
(single-wire mode). They contain two audio channels: “subframe A” and “sub-
frame B”. Usually, the audio channels are:
Subframe A Subframe B
Left Right
Center LFE
Surround left Surround right
Back left Back right
A clock input is not required because subwoofers are not audio sources and the
converters are clocked to a very stable internally generated clock source.
X
Use a Neutrik NADITBNC-F impedance and level converter (not supplied) for XLR to BNC
conversions of AES3-signals. This method brings impedance matching, level matching and
source-receiver isolation. The Neutrik NADITBNC-F converter is guaranteed to work up to
48kHz. Only one converter is needed per digital signal cable.
XUse the following wiring if you want to make your own converter:
CAUTION
Damage to the product due to high AES3 signal levels!
AES3 signal levels in XLR cables are much too high for the DIGITAL INPUT socket
(BNC)0. If you connect such signals without reducing the signals’ level, damage to the
product will occur.
XAlways make sure that your converter is able to match impedance and level.
Wiring Pin Signal
110
cable
AES3 on XLR to AES3 on BNC Connections
75
cable
110
57 mW
54.9
112 mW
187
26 mW
56.2
1.2 mW
Use E96 1% resistors
Source
(XLR-F)
Subwoofer
(BNC)
1Shield
2Signal +
3Signal -
This method brings impedance matching and level matching, but no source-receiver isolation.
Use a resistor network to passively attenuate the XLR signal from 3.1 V down to 0.42V and
change the impedance from 110  to 75 .
Connecting
unbalanced
cables
Connecting
AES cables

KH 750 DSP | 11
Connecting loudspeakers to the subwoofer
For a simplified representation, the following connection examples show loudspeakers in com-
bination with the KH 750 DSP subwoofer. Each of the examples only shows one possible com-
bination of loudspeakers and subwoofers. For information on building a balanced system,
please refer to the “Product Selection Guide” at www.neumann.com.
Either use balanced XLR cables to connect the corresponding ANALOG OUTPUT 8sockets of
the subwoofer to the analog input sockets of the loudspeakers or use the DIGITAL OUTPUT 0
socket for loudspeakers with digital inputs.
Full range stereo (bass managed): two loudspeakers and one subwoofer
XFind the correct cabling diagram below depending on your source signal type (analog or
digital) and the subwoofer/loudspeaker interconnection signal type (analog or digital).
XSet the CHANNEL B INPUT MODE switch Jto STEREO.
Source Signal: Analog
Subwoofer-loudspeaker connections: Analog
Source Signal: Digital
Subwoofer-loudspeaker connections: Analog
Source Signal: Analog
Subwoofer-loudspeaker connections: Digital
Note: Set the left loudspeaker input signal
select to Digital A and the right loudspeaker
input signal select to digital B.
Source Signal: Digital
Subwoofer-loudspeaker connections: Digital
Note: Set the left loudspeaker input signal
select to Digital A and the right loudspeaker
input signal select to digital B.
L
Sub
ANALOG INPUT LEFT/A
ANALOG INPUT RIGHT/B ANALOG OUTPUT RIGHT/B
ANALOG INPUT LEFT/A
ANALOG INPUT RIGHT/B
ANALOG IN
ANALOG IN
ANALOG IN
ANALOG IN
R
L
Sub DIGITAL IN
DIGITAL OUT
DIGITAL IN
DIGITAL IN
DIGITAL OUT
DIGITAL IN
R
L/R
Sub
DIGITAL AES3 INPUT ANALOG OUTPUT LEFT/A
ANALOG OUTPUT LEFT/A
ANALOG OUTPUT RIGHT/B
DIGITAL AES3 OUTPUT
9 8
89
9 0 0
0 8
8
0
9
DIGITAL AES3 OUTPUT
L/R
DIGITAL AES3 INPUT
Sub
Stereo systems

KH 750 DSP | 12
Full range stereo (bass extension): two loudspeakers and two subwoofers
XFind the correct cabling diagram below depending on your source signal type (analog or
digital) and the subwoofer/loudspeaker interconnection signal type (analog or digital).
XSet the CHANNEL B INPUT MODE switch Jto STEREO.
Source Signal: Analog
Subwoofer-loudspeaker connections: Analog
Source Signal: Digital
Subwoofer-loudspeaker connections: Analog
Source Signal: Analog
Subwoofer-loudspeaker connections: Digital
Source Signal: Digital
Subwoofer-loudspeaker connections: Digital
Sub L
Sub R
Sub L
Sub R
ANALOG INPUT LEFT/A
ANALOG INPUT RIGHT/B ANALOG OUTPUT RIGHT/B
ANALOG INPUT LEFT/A
ANALOG INPUT RIGHT/B DIGITAL AES3 OUTPUT
ANALOG IN
ANALOG IN
DIGITAL IN
DIGITAL IN
L
R
L
R
ANALOG OUTPUT LEFT/A
DIGITAL AES3 OUTPUT
Sub L
Sub R
Sub L
Sub R
DIGITAL AES3 INPUT
DIGITAL AES3 INPUT ANALOG OUTPUT RIGHT/B
DIGITAL AES3 INPUT
DIGITAL AES3 INPUT DIGITAL AES3 OUTPUT
ANALOG IN
ANALOG IN
DIGITAL IN
DIGITAL IN
L
R
L
R
ANALOG OUTPUT LEFT/A
DIGITAL AES3 OUTPUT
Note: Set the left loudspeaker input signal
select to Digital A and the right loudspeaker
input signal select to digital B.
Note: Set the left loudspeaker input signal
select to Digital A and the right loudspeaker
input signal select to digital B.
9
9
9
9
8
8
8
8
0
0
0
0
0
0
0
0

KH 750 DSP | 13
Discrete multichannel systems (professional applications)
In multichannel systems, stereo pairs of loudspeakers (L/R, Ls/Rs, etc.) can be connected to
subwoofers as shown above.
X
For the Center and Sub/LFE channels, find the correct cabling diagram below depending on
your source signal type (analog or digital) and the subwoofer/loudspeaker interconnection
signal type (analog or digital).
XThe Center channel must be connected to the analog A input or be located on the digital
A channel. The Sub/LFE channel must be connected to the analog B input or be located on
the digital B channel.
X
Depending on how you wish to handle the Sub/LFE channel, set the CHANNEL B INPUT
MODE switch Jto EXTERNAL BASS MANAGEMENT, LFE-MODE 1 or LFE-MODE 2.
• EXTERNAL BASS MANAGEMENT replays the “Sub” channel full range through the sub-
woofer (preferred setting for already encoded signals or a mixing console with bass
management enabled). In the source equipment, set the loudspeakers to “Small” and
the crossover frequency to 80 Hz.
• LFE-MODE 1 replays the LFE channel up to 120 Hz through the subwoofer (preferred set-
ting for movie mixes, pre-encoded mixes).
• LFE-MODE 2 replays the LFE channel up to 80 Hz through the subwoofer and above 80
Hz through the connected center loudspeaker, thereby giving full range monitoring for
the LFE channel (preferred setting for music mixes).
Source Signal: Analog
Subwoofer-loudspeaker connections: Analog
Source Signal: Digital
Subwoofer-loudspeaker connections: Analog
Source Signal: Analog
Subwoofer-loudspeaker connections: Digital
Source Signal: Digital
Subwoofer-loudspeaker connections: Digital
Note: Set the center loudspeaker input signal
select to Digital A
Note: Set the center loudspeaker input signal
select to Digital A
C
Sub
ANALOG INPUT LEFT/A
ANALOG INPUT RIGHT/B
ANALOG INPUT LEFT/A
ANALOG INPUT RIGHT/B
ANALOG IN ANALOG IN
Sub/LFE
C
Sub
DIGITAL IN DIGITAL IN
Sub/LFE
C
Sub/LFE
Sub
DIGITAL AES3 INPUT ANALOG OUTPUT LEFT/A
ANALOG OUTPUT LEFT/A
DIGITAL AES3 OUTPUT
DIGITAL AES3 OUTPUT
C
Sub/LFE
DIGITAL AES3 INPUT
Sub
9 8 80
00
9
9 0
9
Multichannel
systems

KH 750 DSP | 14
Bass managed multichannel systems (domestic applications)
XIn multichannel systems where there is a bass manager preceding the monitoring system
(for example in surround sound processors), connect the loudspeakers and subwoofer(s)
directly to the source equipment (analog or digital). The “Sub” signal should be connected
to the analog B input or be located on the digital B channel.
XSet the CHANNEL B INPUT MODE switch Jto EXTERNAL BASS MANAGEMENT.
X
In the surround sound processor, set the loudspeakers to “Small” and the crossover fre-
quency to 80 Hz.
Source Signal: Analog
Source Signal: Digital
Sub
Sub
ANALOG INPUT
RIGHT/B
Sub
Sub
DIGITAL AES3
INPUT (B channel)
9 0
Connecting network cables
To use the extended functionality oered by the Neumann.Control software, the subwoofer
must be connected to a standard network switch using a user supplied standard Ethernet cable
(Cat 5 or better). The maximum length of the cable is 100 m.
Refer to the Neumann.Control software help for information about how to use subwoofers in a
network.
RJ45 RJ45 RJ45RJ45
Network Switch

KH 750 DSP | 15
Connecting/disconnecting the subwoofer to/from the
mains power supply
To connect the KH 750 DSP to the mains power supply:
XMake sure that the switch MAINS POWER 3is set to “OFF”.
XConnect the IEC connector of the supplied mains cable to the IEC mains socket 4.
Power Source
3
4
XConnect the mains plug of the mains cable to a suitable wall socket.
To disconnect the KH 750 DSP from the mains power supply:
XSet the switch MAINS POWER 3to “OFF”.
XPull the mains plug out of the wall socket.
Configuring and using the KH 750 DSP
Switching the subwoofer on/o
You can switch the KH 750 DSP on and o using the switch MAINS POWER 3.
XSet the switch MAINS POWER 3 to:
• “ON” to switch the subwoofer on. The POWER ON LEDHlights up red for 5 seconds, dur-
ing which the subwoofer is muted (see below). The POWER ON LEDHthen lights up
green.
• “OFF” to switch the subwoofer o. The POWER ON LEDHlights up red and goes o after
a few seconds. The subwoofer mutes immediately when it is switched o.
There is a five second delay before sound can be heard from the KH 750 DSP and the
loudspeakers connected to the outputs in order to avoid noises (pops) from preceding
equipment switched on at the same time. Conversely, switching o the subwoofer
immediately mutes the audio.
On/o switching
using the switch
MAINS POWER 5

KH 750 DSP | 16
Functionality of the back panel lights
Action Indication
Firmware activities
Subwoofer is booting up Power LED solid red
Subwoofer boot up error Power LED flashing red
Subwoofer firmware is being updated Power LED solid amber
Subwoofer resetting to factory default settings Power LED flashing red
Everyday operation
Operating normally Power LED solid green
Subwoofer in active system is solo’ed in
Neumann.Control
Power LED solid green
Subwoofer system output level is muted
(GUI button on Operate page)
Power LED solid red
Subwoofer system output level is dimmed
(GUI button on Operate page)
Power LED solid green
Bass management disabled Bass management LED o
Bass management active Bass management LED green
Protection
Protection system is activated (takes priority over
other indications)
Power LED red
Neumann.Control Alignment
Setup: Identify the Subwoofer Power LED flashing amber
Guided Alignment: Subwoofer is selected Power LED flashing amber
Manual Alignment: Subwoofer is selected Power LED flashing amber

KH 750 DSP | 17
AUTO STANDBY switch
If the AUTO STANDBY switch Ghas been set to ON, the KH 750 DSP will switch to standby after
90 minutes without an input signal.
Standby means that the network interface, signal processing circuitry and power amplifiers
are all powered down. Standby mode is automatically deactivated when a suciently large
audio signal is detected at the input. The time taken to resume normal operation and hear
sound is 5 seconds. It is possible to change the time and standby signal level before standby
mode is activated using the Neumann.Control software.
Standby can be disabled by moving the AUTO STANDBY switch G to OFF.
CONTROL MODE switch
If the CONTROL MODE switch Ihas been set to LOCAL, the KH 750 DSP will not react to net-
work commands from the Neumann.Control software. Control of the subwoofer will be from the
backplate only.
If the CONTROL MODE switch I has been set to NETWORK, the KH 750 DSP will react to net-
work commands from the Neumann.Control software. All backplate controls marked with “*”
will be ignored.
If the CONTROL MODE switch I is set to NETWORK but there is no network connection and
active Neumann.Control software, the last used network configuration will be used. If the
Neumann.Control software has not been connected before, the default settings will be used.
If you have configured any settings via the Neumann.Control software and you remove the
network cable, the current settings will stay active.
By switching from network control to local control you can easily switch between a configura-
tion set using the Neumann.Control software and settings made directly on the subwoofer.
This can make sense if you want to temporarily use the subwoofer in a dierent location than
your measured studio environment.
The subwoofer does not lose its settings even when disconnecting it from the network or the
mains supply.
Resetting the KH 750 DSP
To reset the KH 750 DSP internal controls to their factory default values:
XSwitch on the KH 750 DSP.
XWhile the power light is solid red during the boot up phase, move the AUTO STANDBY switch
Gup and down repeatedly.
The power light will then flash red while the default settings are being applied before revert-
ing to green.
Firmware update
Firmware updates are done via the Neumann.Contol software. When it is opened it surveys
the network for subwoofers and checks if the firmware is up to date. If a firmware update is
needed, you will be prompted to follow the on-screen instructions. It takes approximately 1.5
minutes per subwoofer to do the update.

KH 750 DSP | 18
Calibrating the subwoofer
Before using your system for the first time and whenever you change the physical conditions in
your listening environment, carry out the following steps:
XAdjust the frequency response and the level of the loudspeakers before calibrating the sub-
woofer (see the operating manual of the loudspeakers):
Application Recommended frequency response Comments
Studio flat A flat response brings good
translation
Film X-curve shape ANSI/SMPTE 202M:
the shape of the X-curve
depends on the size of the room
Home subjective evaluation Not necessarily a flat response,
a gently downward sloping
response with increasing
frequency is often preferred
All the loudspeakers in the system should have the same level at the listening position. This
is often measured using a pink noise test signal that is set to -18 dBFS (Europe) or -20 dBFS
(USA) on the mixing console’s output level meters and a sound level meter set to “C-weighted”
and “slow”.
XCalibrate the frequency response, the phase and the acoustical level of the subwoofer.
To do so, choose one of the following methods:
1. Alignment using Neumann.Control:
It is highly recommended to use Neumann.Control to calibrate the loudspeakers and
subwoofer in the room. Download the software and choose an Alignment method that
suits your circumstances: Precision, Guided, Manual.
2. Calibration using the backplate controls:
A: Calibration using an acoustical measurement system
Calibrating the frequency response, phase and sound pressure level by means of an
acoustical measurement system should always be your first choice since it yields the
highest accuracy. This method is described below.
B: Calibration using Neumann test signals
In the absence of an acoustical measurement system, you can calibrate the settings of
your subwoofer using Neumann test signals (see page 20).
C: Calibration using music signals and an 80 Hz test signal
A calibration by means of music signals is also possible but should always be the last
choice. In this case, play an 80 Hz test signal from your source equipment to calibrate
the phase (see page 20).
For setting up one or several subwoofers via Neumann.Control follow the on-screen
instructions.

KH 750 DSP | 19
Calibration using the backplate controls and an acoustical measurement system
The settings of the switch SUBWOOFER GAIN | OUTPUT LEVEL Aand the potentiometer
SUBWOOFER GAIN | INPUT GAIN Brecommended in the following table are valid for
the following settings of your Neumann loudspeaker: INPUT GAIN: “0 dB” and OUTPUT
LEVEL: “100 dB SPL at 1m for 0 dBu”. For information on how to set your Neumann
loudspeaker, please refer to its operating manual. If the mentioned values cannot be set
on your loudspeaker, adjust the subwoofer accordingly.
The frequency response of a subwoofer depends on its position in the room and on the room
geometry. The same subwoofer installed in dierent positions in the same room may require
dierent acoustical control settings.
XAdjust the frequency response of the subwoofer at your listening position. To do so, proceed
as follows:
X
Make sure that the switch SUBWOOFER GAIN | OUTPUT LEVEL Ais set to “100 dB SPL at 1m
for 0 dBu”.
X
First, set the potentiometers SUBWOOFER GAIN | INPUT GAIN Band LOW CUT 5to the
following settings. These settings can be used as a starting point for further adjustment:
Subwoofer position Setting of potentiometer
SUBWOOFER GAIN | INPUT GAIN B
Setting of potentiometer
LOW CUT 5
In a corner -8 dB 0 dB
Next to or flush
mounted in an
acoustically solid
wall (e.g. brick,
concrete)
-4 dB 0 dB
Next to or flush
mounted in an
acoustically soft
wall (e.g. gypsum)
-2 dB 0 dB
Free standing in an
untreated room
-2 dB 0 dB
Free standing in a
well-treated room
0 dB 0 dB
XCheck the frequency response at the listening position using your acoustical measurement
system:
• In the case of excessive very low frequency levels at the listening position, turn the
potentiometer LOW CUT 5 to the left. This reduces the output level of the subwoofer
towards lower frequencies.
XMeasure the subwoofer’s sound pressure level at the listening position.
XAdjust the sound pressure level of the subwoofer so that the level of the frequency response
of the subwoofer below 80 Hz corresponds to the level of the frequency response of the
loudspeakers above 80 Hz.
• To do so, use the potentiometer SUBWOOFER GAIN | INPUT GAIN Band the switch
SUBWOOFER GAIN | OUTPUT LEVEL A. Make sure that the input signal is not too high.
XSet the phase using the left switch SUBWOOFER PHASE D. Values from -180ºto -315º can
be obtained by setting the right switch SUBWOOFER PHASE Cto “–180º” and by adding the
set value of the left switch SUBWOOFER PHASE D.
Example: To obtain a phase shift of –270º, set the right switch SUBWOOFER PHASE Cto
“–180º” and the left switch SUBWOOFER PHASE Dto “–90º”.
XSet the left switch SUBWOOFER PHASE Din combination with the right switch SUBWOOFER
PHASE Cto values of 0º, -45º, -90º, -135º, -180º, -225º, -270º, and -315º, until you have
found the setting that gives the lowest sound pressure level at the listening position at the
cut-o frequency of 80 Hz (180º phase shift between subwoofer and loudspeaker, maximum
level cancelation).
Calibrating the
frequency
response
Calibrating the
subwoofer level
Calibrating the
phase

KH 750 DSP | 20
X
Set the right switch SUBWOOFER PHASE Cto the opposite position. The phase shift between
loudspeaker and subwoofer is now 0º. Check your subwoofer’s sound pressure level again
and, if necessary, readjust it so that it corresponds to the sound pressure level of the
loudspeakers.
Your system is now completely acoustically calibrated.
Note that any change of the low cut influences the crossover phase. Therefore, the
phase and the level need to be recalibrated after changing the low cut EQ setting.
Calibration using the backplate controls and Neumann test signals
XDownload the Neumann test signals and the instructions for use (PDF file, in English) from
the KH 750 DSP product page at www.neumann.com.
XFollow the steps described there.
Calibration using the backplate controls, music signals and an 80 Hz test signal
X
Adjust the settings for the sound pressure level and the frequency response as described
above.
X
Calibrate the acoustical phase using an 80 Hz test signal. Check the settings of the sound
pressure level and frequency response by means of music signals you are familiar with.
• Connect the left front loudspeaker to the socket OUTPUT | LEFT 8.
• Set the switch BASS MANAGEMENT Eto “ACTIVE”.
• Play an 80 Hz test tone from your source into the audio input INPUT | LEFT 9so that the
subwoofer and left loudspeaker are playing the tone.
• Set the left switch SUBWOOFER PHASE Din combination with the right switch SUB-
WOOFER PHASE Cto values of 0º, -45º, -90º, -135º, -180º, -225º, -270º, and -315º,
until you have found the setting that gives the lowest sound pressure level at the listening
position at the cut-o frequency of 80 Hz (180ºphase shift between subwoofer and loud-
speaker, maximum level cancelation).
• Switch o the test signal at the source.
• Set the right switch SUBWOOFER PHASE Cto the opposite position.
The phase shift between loudspeaker and subwoofer is now 0º.
X
Check the settings of the sound pressure level and frequency response by means of music
signals. Listen for a smooth extension of the frequency response of the main loudspeakers
down to 20 Hz.
To to this, proceed as follows:
X
Listen to music containing content down to 20 Hz. Activate and disable the bass management
by repeatedly moving the switch BASS MANAGEMENTEbetween the two positions. There
should be no increase or decrease in level between the lower cut o frequency of the loud-
speaker and 80 Hz.
Compensating for larger time of flight (TOF) dierences
If the subwoofer is placed at a distance > 2 m (6'6") behind the loudspeakers with reference to
the listening position, the subwoofer back panel phase controls will not suce. In this case
use Neumann.Control to access the built-in delay functionality.
Using the bass management
X
For a two-channel stereo system set the switch CHANNEL B INPUT MODE Jto “STEREO/
RIGHT”.
XSet the switch BASS MANAGEMENT Eto “ACTIVE”.
The bass management is activated. This inserts a 4
th
order 80 Hz high pass filter into the
signal path of the audio outputs OUTPUT | LEFT and RIGHT 8and routes all audio signals
below 80 Hz to the subwoofer. The LED BASS MANAGEMENT Flights up green.
If you deactivate the bass management, the audio signal of the audio outputs OUTPUT | LEFT
and RIGHT 8is only reproduced by the loudspeakers. Use this function to prevent the low
frequency signal components of the main channels being reproduced by the subwoofer.
XSet the switch BASS MANAGEMENT Eto “DISABLED”.