HEDD BASS 08 User manual

© 2021 HEDD Audio GmbH | Heinz Electrodynamic Designs | www.hedd.audio
OPERATION MANUAL
HEDD BASS 08 HEDD BASS 12
Heinz Electrodynamic Designs
last updated: 2021-05-20

-2-
Table of Contents
Introduction and Quickstart
Box Contents
Product Overview
Status LED
CoP: Closed or Ported
HEDD Lineariser®
Control Settings
Safety Instructions
Warranty
Troubleshooting
Technical Specications
A Brief History of Time
3
4
5
7
8
9
11
15
17
18
19
20

© 2021 HEDD Audio GmbH | Heinz Electrodynamic Designs | www.hedd.audio
Introduction & Unpacking
Thanks a lot for choosing HEDD BASS subwoofer
All BASS subwoofer models have an identical backplate so this Manual works for all of them.
The BASS subwoofers monitors oer detailed and partly new kinds of controls, so we invite you to
read through the following sections carefully.
Please unpack your new loudspeaker carefully. If you discover any damage to the packaging or the
speaker itself, don’t operate the speaker and contact your HEDD dealer for solving the problem.
We suggest that you allow the speaker to acclimate to the temperature of your room for about an
hour before using it.
Quick Start
• Make sure the main power switch is in the “0” position, then connect the power cord to the power-
socket.
• Set the power switch to “1”
• Connect your audio source via the balanced XLR or the AES in socket, then select the desired input
with the ANALOG / AES rotary switch.
As there are quite a number of control knobs on the backplate we recommend to start playing music
with all markers in the “Up” position: ALL "0" and "
↑
" POSITION = FACTORY SETTING
Enjoy the music.
PS: Please save the original box as it provides the safest way for a future transportation of your
speaker.

-4-
Box Contents
The complete set includes:
• one active subwoofer HEDD BASS 08 or BASS 12
• one power cable compatible with the region from where it was sold
• quickstart guide
• «CoP» leaet explaining the proper switch from Ported to Closed Mode
• «CoP» screw and plugs to seal the bass reex ports
Please make sure your box contents match our listing.
QUICKSTART
BASS Subwoofer
How to switch between Closed and Ported

© 2021 HEDD Audio GmbH | Heinz Electrodynamic Designs | www.hedd.audio
Product Overview
Congratulations on purchasing the HEDD BASS 08 or BASS 12. You have acquired very
precise subwoofer with a rich feature set. The main features are exchangable use as a Closed
or Ported system, as well as the integration of the on-board HEDD Lineariser®. Please head
to the specic section to nd out more.
As active subwoofers, the BASS subwoofers have an integrated amplier. You can connect
them with a digital interface or analog pre-amplier. Please refer to the section Getting
Started or Positioning to nd out more.
Due to their similar nature, this operation manual equally covers the HEDD BASS 08 and
HEDD BASS 12 subwoofers. This manual uses illustrations of the dierent variants, which
thus might not match your exact version in terms of appearance.
Front View
HEDD Honeycomb Woofer
size 8’’ or 12’’ respectively
Front-facing Bass Reex Port
can be used ported or closed
with included plugs
Status LED
please refer to section Status LED to correctly read the signal

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ANALOG INP TS
O TP TS TO SATELLITES
VOL. [dB] LINEARISER®CoP
-1
-2 +2
+1
0
60
40 200
100
120*
80
*FOR LFE
EXTEND.
(less SPL)
NORMAL
+10 dB FOR LFE
MONO LEFT
ANALOG
RIGHT
-4 +4
0
-10
-90-270
0
-180
-6
-12 +12
+6
0 ON
OFF
(*)
Ported
Closed
SAT. OFFSET [m] X-OVER [HZ] LF RANGE
ANALOG/AES INP. SENS. [dB] PHASE [°]
ALL "0" and "↑" POSITION = FACTORYSETTING
!
RISK OF
ELECTRIC SHOCK
DO NOT OPEN
MADE IN GERMANY - www.hedd.audio
SUBWOOFER
This loudspeaker is capable of delivering sound
pressure levels in escess of 85 dB(A), which may
cause permanent hearing damage.
Do not expose this appliance to moisture or rain.
Refer to qualied personnelfor servicing.
CAUTION
CAUTION
I
O
AES IN LEFT RIGHT
AES THROUGH LEFT RIGHT
1
3
2
PUSH
1
3
2
PUSH
1
3
2
PUSH
85V - 264V 50Hz/60Hz
factory use only
BASS Control Board
used for adjusting the various settings
please see section Control Settings
Rear View
In- & Output Connections
XLR analog & AES digital input
XLR analog output & AES passthrough
Power Switch
integrated universal mains, compatible with 85V - 264V at 50/60 Hz
appropriate power cable supplied

© 2021 HEDD Audio GmbH | Heinz Electrodynamic Designs | www.hedd.audio
Status LED
The front LED panel of the subwoofer will indicate its operational status as follows:
The monitors automatically jump into stand-by after 30 minutes. They wake back up when
audio is played.
Subwoofer placement
Only recommendations can be given here as the interaction between a subwoofer and the
rooom modes (that are responsible for the standing waves that may occur) are complex and
not predictable:
• Avoid placing subwoofers near walls.
• Denitively avoid subwoofers in corners.
• Try to watch a minimum distance of 50 cm between subwoofers and adjacent walls.
Green Light
power on
Red Light
overload: please decrease the input sensitivity
White Light
stand-by

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«CoP» Closed or Ported
The HEDD Type 20 MK2 and Type 30 MK2 can be used in either closed or in ported
mode. These are two fundamentally dierent systems that are available for the user to
compare and choose. There is no denite better between the two systems. We
recommend to compare carefully to nd the optimal option for your environment and
listening habits.
Switching Between Closed and Ported
By default, the HEDD speakers are "ported." This means that the bass port is open. To
switch to "closed" mode, please follow the steps below.
1. Insert the included HEDD plugs with help of the HEDD screw to close the ports.
Make sure that the screw is facing outwards!
Push the plugs deep into the bass ports. Make sure that you
can still reach the screw comfortable with your ngers to
pull it out. The plug should not go deeper than when the
bass port starts to bend and the resistance increases. Once
inserted, feel free to unwind and remove the screw.
2. Switch the knob on the backpanel of your monitors to Closed mode.
Please note that the headroom in Closed Mode is limited compared to Ported Mode.
We highly recommend to lower the volume before switching.
from Closed to Ported
To switch back to Ported Mode, stop the audio
playback, wind the screw back into the plug, gently
pull the plug back out again and change the rotary
switch on the backpanel to Ported.
!
!

© 2021 HEDD Audio GmbH | Heinz Electrodynamic Designs | www.hedd.audio
Ported Mode
This is the default operating mode. The bass reex ports are open and allow for a powerful
low-end reproduction. This operation mode allows for a higher eciency and while
maintaining access to lower bass regions.
Closed Mode
In closed mode the HEDD BASS subwoofer functions as an innite bae speaker. This
results in a cleaner sound and increased resolution. However, a 6-10 dB reduction in
maximum sound pressure level (depending on the audio material) for low frequencies is
the consequence.
CoP
Ported
Closed
CoP
Ported
Closed

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HEDD Lineariser®
Due to the physically given relationship between time and frequency, expressed in the
groundtaking harmonic analysis or Fourier transform, dierent tones have slightly
dierent travelling times through loudspeakers. This is true for both active or passive
speakers. Broadly speaking, lower frequencies need more time to pass through than
midrange frequencies, and these are slower than the high tones.
Our HEDD Lineariser® oers a complex phase-correction of your HEDD sat-sub
system. It solves one of the most challenging problems in loudspeaker designs, e.g. the
natural occurance of phase dierence during multi-component sound reproduction.
With the on-board Lineariser®, our monitors and subwoofers are always “right in time”.
The phase-linearisation will improve transients and imaging. To be noted: the correction
necessarily will introduce a latency of around 30 ms. To avoid the delay that might aect
live recordings or instrument playing the HEDD Lineariser® can be switched o.

© 2021 HEDD Audio GmbH | Heinz Electrodynamic Designs | www.hedd.audio
Control Settings
Volume
The output volume rotary switch changes the reproduction level in a ± 12 dB range. We
recommend to ne-tune the volume through the connected source like an interface,
control board, mixing board or pre-amp.
The output volume allows to match the speakers to the audio chain, e.g. lowering SNR or
THD. The default setting is 0 dB.
When viewing in PDF, please click the corresponding switch to jump to the appropriate section.
VOL. [dB] LINEARISER®CoP
-1
-2 +2
+1
0
60
40 200
100
120*
80
*FOR LFE
EXTEND.
(less SPL)
NORMAL
+10 dB FOR LFE
MONO LEFT
ANALOG
RIGHT
-4 +4
0
-10
-90-270
0
-180
-6
-12 +12
+6
0 ON
OFF
(*)
Ported
Closed
SAT. OFFSET [m] X-OVER [HZ] LF RANGE
ANALOG/AES INP. SENS. [dB] PHASE [°]
ALL "0" and "↑" POSITION = FACTORY SETTING

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HEDD Lineariser®
By default, the Lineariser rotary switch is turned on. This activates an on-board phase-
correction of our HEDD BASS subwoofers.
For more information, please refer to the section HEDD Lineariser®.
Closed or Ported
CoP switches the internal system layout according to the selected option. Please make
sure that the plugs are correctly inserted for closed mode.
For more information, please refer to the section Closed or Ported.
Satellite Oset
With HEDD MK2 monitors and HEDD BASS subwoofers it is possible to build completely
linear phase Satellite-Subwoofer set-ups. This works best when satellites and subs have
the same distance with respect to the listener. For more details please read the “ A Brief
History of Time” section at the end of this manual.
In case the subwoofer has to be placed at a shorter or a longer distance the dierences in
travelling time of the sound can be compensated. Taking the sub position as given, with
the Sat OFFSET control you can add or subtract ± 2 m in satellite distance with respect
to the sub location. +1 m means the satellites are 1 m farer away than the subwoofer etc.
- 1m + 1m

© 2021 HEDD Audio GmbH | Heinz Electrodynamic Designs | www.hedd.audio
Crossover (X-Over)
Dierent crossover frequencies are selectable by this control. In practice the 80 Hz
position has established itself as a quasi-standard and we recommend it as well. Should
you intend to set up a linear phase satellite-sub system you have to choose 80 Hz to make
the phase linearization really working.
LFE option
Sometimes multi-channel audio tracks have a separate audio channel, referred to as low-
frequency eects (LFE).
For the use in LFE channel set-ups the BASS subwoofers can be set to LFE, the preferred
format for lm sound reproduction. The Format means a 120 Hz crossover point and an
additional + 10 dB level.
These two settings are available at the controls:
• X-Over: 120 Hz for LFE
• LF Range: +10 dB for LFE
Should an AV receiver be responsible for the bass management, please set the X-Over
control to “120 Hz for LFE” and the LF Range control to “normal”.
Low Frequency Range
The default low frequency range may be adjusted according to specic needs. When set
to extended, the low frequency response is extended by ~20 %. In the case of BASS 12 it
goes from 20 Hz (-3 dB) down to 16 Hz (-3 dB).
Due to the now much bigger amplitudes the woofer has to manage the maximum sound
pressure level SPLmax is reduced by 6-12 dB depending on the kind of music.
60
40 200*
100
120*
80
*FOR LFE
EXTEND.
(less SPL)
NORMAL
+10 dB FOR LFE
SAT. OFFSET [m] X-OVER [HZ] LF RANGE

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Analog/AES
This 4-position rotary switch functions as input selection. “Analog” takes an analog signal
from a symmetrical source.
The other 3 positions refer to an incoming digital AES signal. Left, Right or Mono can be
extracted from the data.
Input Sensitivity
The “Input Sensitivity” rotary switch levels the voltage of the analog input. It can be used
to optimize the signal to noise ratio for the A/D converter. In case of weak input signals
the gain can be added for up to +4 dB. In case of very loud signals (>2 V) either -4 or -10
dB gain reduction can be applied to avoid an A/D converter overload.
The setting has no eect when the signal is received through the digital AES input.
Phase
Due to dierent positions between Sub and Satellite it might be recommendable to
switch the phase from 0 to 180 °, in some cases to 90° or 270° corresponding to timely
optimisation in the crossover region, it is not clearly predictable due to the room -
subwoofer coupling.

© 2021 HEDD Audio GmbH | Heinz Electrodynamic Designs | www.hedd.audio
Safety Instructions
Please read the following safety instructions carefully before setting up your system. Keep the
instructions for subsequent reference. Please read the warnings and follow the instructions.
• To reduce the risk of an electric shock, do not open the loudspeaker yourself. Always refer to
qualied service personnel.
• This is an active loudspeaker. It must be connected with an IEC 60320 AC mains power cord
like the one supplied with the product.
• Please switch o your audio system before connecting or disconnecting any cables to the
speaker – also if you intent to clean the surface or single components. Never use ammable
or combustible chemicals for cleaning audio components.
• HEDD studio monitors are equipped with universal mains, meaning that the speakers work
within a voltage range from 85–265V. This makes the usual voltage switches unnecessary.
• Do not place this unit on an unstable cart, stand or tripod, bracket or table. The unit may fall,
causing serious injury and/or serious damage.
• This product should never be used outside. Avoid exposing it to rain or any sort of moisture.
• Power chords and audio cables connected to this product should never be stepped on.
• Please note that defective cables can harm your speakers and / or create humming, crackling,
etc.
• Always keep electric equipment out of the reach of children.
• Always unplug sensitive electronic equipment during lightning storms.
• The monitor should be installed near the socket outlet and disconnection of the device should
be easily accessible.
• To completely disconnect the speaker from the AC mains, physically disconnect the power
chord.
• Please try to avoid touching the speaker diaphragms. Always keep the woofer’s ventilation
ports open.
• Don't use the speaker at very high or low temperatures. The speakers’ back panel should not
be exposed to direct sunlight. Never operate this product in an explosive atmosphere.
• High SPL’s can irreparably damage your ears! Please take good care when working the
speakers at high levels.
• Loudspeaker diaphragms are embedded in strong magnetic elds. Magnetic objects (toys
etc.) should not be placed or played around with next to the speakers.
• Make sure that the air can circulate behind the speaker as it needs sucient cooling.
• Only mount this product onto dry and non-conducting walls (wood, plaster). For other wall
materials an additional isolation panel is required. To prevent injury, this loudspeaker must be
securely attached to the wall in accordance with the installation instructions of your wall
mount bracket.

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Maintenance and Care
• Your HEDD BASS subwoofer doesn’t need any internal maintenance like
lubricating, mechanical adjusting and so on, so there is no reason to open up the
speaker cabinet. If servicing will be necessary, refer to qualied service personnel.
• For cleaning the surface of the cabinet, we recommend to use a microber cloth
and simply warm water. Don’t use any aggressive detergent, as it will damage the
nish.
• For cleaning dust out of the loudspeaker diaphragms, use a very soft brush.
• Always switch the speaker o before cleaning!
• Make sure that no liquids get inside the cabinet.
• Don’t use ammable or acidic chemicals for cleaning.
Shipping and Packaging
If you need to send your speakers postal, use the original packaging. It’s the safest way
to get your speakers from A to B.
HEDD Audio GmbH cannot be held responsible for any damage due to improper
packaging.
Environmental Information
All our products comply with RoHS and WEEE.
If your speaker is seriously broken, please consult your local authorities for further
information on proper disposal.

© 2021 HEDD Audio GmbH | Heinz Electrodynamic Designs | www.hedd.audio
Warranty
We promise that our products are free of defects in material and workmanship for the
duration of twenty-four (24) months from the date of the original purchase. This
warranty can be extended to thirty-six (36) months if the product is registered with us
within the rst 6 months after purchase: hedd.link/registration
Accessories and any parts that are subject to wear and tear are covered for six (6)
months.
The latest updates to our warranty will be accessible online at hedd.audio/warranty/
Please always contact your point of sale rst: Please check our list of authorized
resellers: https://hedd.audio/store-locator/
Limitations
Please note that inappropriate use voids the warranty and any claims.

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Trouble Shooting
If none of these advices solves the problem, the speaker might be faulty. If you need
further assistance, please contact us directly: [email protected]
Problem Solution
Green Power-LED is “on” but there
is no audio output
1. Check the wiring and make sure that all cables are
connected correctly.
2. Check if you have selected the correct input via the
ANALOG/AES switch on the back panel of the speaker.
3. Check the signal path. Swap the cables of both loud-
speakers. You might have one defective signal cable.
4. Connect an audio source directly to the speaker (pay
attention to the volume!). If you now have audio output, the
malfunction is in your signal path.
5. If the back panel of the speaker is very hot, it may be that
the internal thermal protection of the ampliers has shut down
the audio output to prevent electrical damage. Turn the unit
o, let it cool down and repower.
There is a hum or buzz noise in the
output
1. Disconnect all signal cables. If the noise is gone, check your
audio cables and the equipment of your signal path. If you are
using the balanced XLR input, try to activate Ground Lift on
your signal source.
2. If there is still noise, check if you have any other electrical
devices that potentially produce high amounts of RFI
(cellphones, switching power supplies, radio equipment) next to
your speakers. If so, move them further away.
3. Try connecting the speakers to a dierent power socket.
Red Overload-LED lights up
constantly
Reduce the input audio level either on the source or with the
Inp. Sens. control and increase the Vol. instead.

© 2021 HEDD Audio GmbH | Heinz Electrodynamic Designs | www.hedd.audio
Technical Specications
HEDD Subwoofers BASS 08 BASS 12
Woofer (honeycomb diagram) 8’’ (2’’ voice coil) 12’’ (2.5’’ voice coil)
Frequency response (-3 dB) 24 - 80 Hz 20 - 80 Hz
Upper frequency limit (var.) 40 - 120 Hz 40 - 120 Hz
LF range (-3 dB): normal / extended 24 / 20 Hz 20 / 16 Hz
LFE function (LowPass lter +10 dB gain) LP 200 Hz / +10 dB LP 200 Hz / +10 dB
Input 1: analog stereo (2ch) / impedance 2x XLR / 22 kΩ 2x XLR / 22 kΩ
Input 2: AES “in” 1x XLR 1x XLR
Output: AES “through” 1x XLR 1x XLR
Output to satellites (2ch) highpass @ 80 Hz L/R 4th order 80 Hz L/R 4th order
Satellite oset @ANALOG OUT ± 2m in .5m steps ± 2m in .5m steps
Sensitivity (Inp. Sens.: 0 dB, Vol.: +12 dB) 90 dBSPL 1W/m 96 dBSPL 1W/m
Input gain ± 12dB ± 12dB
Input sensitivity -10 / 4 / 0 / +4 dB -10 / 4 / 0 / +4 dB
HEDD Lineariser®, disengageable, delay 30 ms 30 ms
Phase switch 0 / 90 / 180 / 270° 0 / 90 / 180 / 270°
Maximum SPL at 1 m (half space) 105 dB 115 dB
Power amplier / universal mains 110 - 240 V 300 W ICEpower 700W ICEpower
AD/DA Conversion 96 kHz / 32 Bit 96 kHz / 32 Bit
Cabinet with satin lacquer nish black black
Dimensions (H x W x D) 392 x 290 x 400 mm 595 x 380 x 610 mm
Weight 17 kg 32.1 kg
Warranty 2 years 2 years

- 20 -
A Brief History of Time
(within subwoofers, this time)
by Klaus Heinz
Subwoofer are in use since many decades, their integration into the reproduction chain allows to
add fundamental frequencies where small speakers meet their limits. However, the use of
separate bass units often shows two typical unwanted side eects: the woofer section appears
to be separated or not really integrated into the overall sound image, and the low frequencies
themselves tend to sound somewhat boomy or weakened. Before we started to build subwoofers
we took a closer look at the reasons for these widely experienced problems. The answer we found
is: time.
Already in single loudspeakers one can observe that lower frequencies need more time to travel
through the speaker than higher frequencies. In Satellite-Sub systems additional time shifts
occur at the crossover points and the involved high-and lowpass lters both in satellites and
subwoofers. All in all some timely confusion is added in the reproduction chain by loudspeakers,
let us see why.
As we deal with sound a principal physical remark has to be made: soundwaves are completely
characterized by time and frequency. Between these two there is a fundamental physical
relationship called the Harmonic Analysis. It states that each change in the frequency response
of a loudspeaker inevitably causes a corresponding change in the Phase Response.
But what is a “Phase Response”?
A phase describes the timely distance between two events, nothing more. So if a tone starts at
exactly 12 pm and another one at 12:01 pm the phase delay is 1 minute. As a consequence of the
Harmonic Analysis phase delays in loudspeakers necessarily occur due to the nonlinearities in
their frequency response. These delays range from <1 ms (Millisecond) to appr. 50 ms, depending
on the transmitted bandwidth and some DSP internal settings.