HEDD BASS 08 Ultra Compact Subwoofer Instruction Manual

June 3, 2024
HEDD

HEDD logo BASS 08 Ultra Compact Subwoofer
Instruction Manual

BASS 08 Ultra Compact Subwoofer

Heinz Electrodynamic Designs
OPERATION MANUAL
HEDD BASS 08
HEDD BASS 12
last updated: 2022-02-03
© 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 offer 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 powersocket.
  • 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.

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» leaflet explaining the proper switch from Ported to Closed Mode
  • «CoP» screw and plugs to seal the bass reflex ports Please make sure your box contents match our listing.

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 specific section to find out more.
As active subwoofers, the BASS subwoofers have an integrated amplifier. You can connect them with a digital interface or analog pre-amplifier. Please refer to the section Getting Started or Positioning to find 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 different variants, which thus might not match your exact version in terms of appearance.
Front View
Rear View

Status LED
The front LED panel of the subwoofer will indicate its operational status as follows:

****| Green Light
power on
---|---
| Red Light
overload: please decrease the input sensitivity
| White Light
stand-by

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.
  • Definitively avoid subwoofers in corners.
  • Try to watch a minimum distance of 50 cm between subwoofers and adjacent walls.

«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 different systems that are available for the user to compare and choose. There is no definite better between the two systems. We recommend to compare carefully to find 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 fingers 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.
Ported Mode
This is the default operating mode. The bass reflex ports are open and allow for a powerful low-end reproduction. This operation mode allows for a higher efficiency and while maintaining access to lower bass regions.
Closed Mode
In closed mode the HEDD BASS subwoofer functions as an infinite baffle 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.

HEDD Lineariser®

Due to the physically given relationship between time and frequency, expressed in the groundtaking harmonic analysis or Fourier transform, different tones have slightly different 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® offers 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 difference 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 affect live recordings or instrument playing the HEDD Lineariser® can be switched off.

Control Settings

When viewing in PDF, please click the corresponding switch to jump to the appropriate section.

Volume
The output volume rotary switch Vol. changes the reproduction level of the subwoofer and connected satellites in a ± 12 dB range. It is an analog volume control after the DA converter. We recommend to set the Vol. of the BASS unit to +12dB and set the Vol. of the Satellite to the value you can find in the following table:

Recommended Vol. Setting BASS 08 BASS 12
TYPE 05 MK2 +3 dB +6 dB
TYPE 07 MK2 +3 dB +6 dB
TYPE 20 MK2 -3 dB 0
TYPE 30 MK2 -3 dB 0

We further recommend to fine-tune the volume through the connected source like an interface, control board, mixing board or pre-amp. For sources with high level outputs (i.e. +4dBu) we recommend selecting -10 or -4 on the Input Sens. control. For sources with low level outputs (i.e. -10dBV) we recommend to select either 0 or +4.
Please note that these settings are based on use in an optimally-treated room for linear frequency response. Please adjust the Vol. individually to match influences like the shape of your room, the position of the subwoofer, distance to the wall, etc. In some cases, it might even be necessary to balance the monitors with an uneven Vol. setting.
If you wish to increase bass presence, please lower the Vol. setting on the satellites. Likewise, to reduce low-end pressure, increase the volume of the satellites.
In the case that the Limiter LED lights up on your speaker: Please reduce the Input Sens. on the speaker that has the Limiter LED lighting up and increase the Volume by the same amount.
HEDD Lineariser®
By default, the Lineariser rotary switch is turned on. This activates an on- board phasecorrection 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 Offset
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 differences 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.

Crossover (X-Over)
Different 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 lowfrequency effects (LFE).

For the use in LFE channel set-ups the BASS subwoofers can be set to LFE, the preferred format for film 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 specific 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.
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.

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 qualified 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 off 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 flammable 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 85­265V. 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 fields. 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 sufficient 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.

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 qualified service personnel.
  • For cleaning the surface of the cabinet, we recommend to use a microfiber cloth and simply warm water. Don’t use any aggressive detergent, as it will damage the finish.
  • For cleaning dust out of the loudspeaker diaphragms, use a very soft brush.
  • Always switch the speaker off before cleaning!
  • Make sure that no liquids get inside the cabinet.
  • Don’t use flammable 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.

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 first 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 first: Please check our list of authorized resellers: https://hedd.audio/store-locator/

Limitations

Please note that inappropriate use voids the warranty and any claims.

Trouble Shooting

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 loudspeakers. 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 amplifiers has shut down the audio output to prevent electrical damage. Turn the unit off, 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 different 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.

If none of these advices solves the problem, the speaker might be faulty. If you need further assistance, please contact us directly: info@hedd.audio

Technical Specifications

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 filter +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 offset @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
Maximum Input @ Input Sens. 0| 4 dBu| 4 dBu
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 amplifier / 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 finish| 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

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 effects: 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 filters 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.
Within a subwoofer all frequencies between 20 Hz and typically 80 Hz should be reproduced at the same point in time of course, but as mentioned due to internal filters and driver properties delays of different durations are added at different frequencies:
Lower frequencies travel longer through speakers than higher ones.
In other words: the phase response of a subwoofer falls from higher travelling times – like 50 ms at ~20 Hz ­ down to 10 ms at ~80 Hz, which has become the standard crossover frequency between subs and satellites. With respect to frequency these different delays vary in a characteristic way for each subwoofer, they are represented in a curve called phase response. In analog times there was no way to avoid these phase errors.
With today’s powerful DSP’s it is possible to apply FIR (for Finite Impulse Response) filters that are able to correct these deviations, but they only can achieve it on cost of an overall delay for the through passing signal. To do the job the filters need to “know” what’s wrong in the time and frequency domain of the speaker, technically speaking they need the measured Impulse Response (IR) of the subwoofer under consideration. The IR’s of BASS 08 and BASS 12 have been measured in the big anechoic chamber of the Technical University Berlin and implemented in the DSP boards to deliver that information. It contains all their frequency and phase nonlinearities and can be used to correct the speaker in real time. The HEDD Lineariser®, an adapted FIR (Finite Impulse Response) filter is the mathematical tool of choice that reinstalls the original timely relationships of the incoming musical signal. The audibly improved transient response and a better focused stereo localization are evident benefits.
Having done this the phase response in the subwoofers now is linear, but as mentioned this has to be “paid” by an overall delay of ~40 ms for a down to 20 Hz (- 3 dB) frequency response. The DSP has to wait these 40 ms before the sound can be put through to the power amplifier and out of the box. As a consequence all frequencies between 20 and 80 Hz are delayed by 40 ms, it is called a group delay of 40 ms. It means the sub starts the low frequencies 40 ms later compared to the sound of the satellites. Wait ­ the HEDD MK2 satellite themselves have a Lineariser® too, in their case – because their response is set to > 80 Hz – their group delay is 10 ms only.
To solve the timing problems completely we implemented two more DSP channels that add a 30 ms group delay to the analog “Outputs to Satellites” XLR sockets at the backplates of the BASS 08 and BASS 12 subwoofers.
The Satellites now “wait” these 30 ms until the subwoofer emits its low frequency signals, then – if the satellite Lineariser is “ON” – add their own group delay of 10 ms – and well there we are: 40ms later, all 3 loudspeakers start reproduction at the very same millisecond, and they do it for each and every frequency in the complete audio band.
One more thing: in practice it often is difficult to set up satellites and subwoofers at the same listening distance. As only with equal distances the above considerations really work we have added a distance control called “SAT. OFFSET [m]” at the back panels of the subs. It allows to compensate the potential difference in travelling time between satellites and subwoofers if necessary, it actually would mean a new additional phase error. You may adapt to a ± 2m runtime difference between satellites and subwoofers in a .5 m resolution, that should cover the problem in most of the cases.
All components of HEDDs Linear Phase Satellite-Sub systems start the sound reproduction at the same point in time, and do so with the timely correct relationships within the audible band as to be found in the incoming music signal.
With the combination of HEDDs Linear Phase satellites, BASS Linear Phase subwoofers and an appropriate compensation for the longer group delay of the subwoofers, we actually have wiped out the standard problems that have been inherent in the use of subwoofers right from the beginning – until now.
We think we have found and eliminated the main reasons for inhomogeneous and boomy sound in Satellite-Sub systems. We at HEDD would be happy if you take the time for an audition, the proof as we do know is in the listening.
HEDD Subs and Satellites are “Right in Time”
Heinz Electrodynamic Designs
HEDD | Heinz ElectroDynamic Designs is a high-end audio manufacturer founded by Klaus Heinz and Dr. Frederik Knop. Drawing on a rich history in audio creation and reproduction, the German company builds handcrafted professional studio monitors, subwoofers, and headphones in Berlin since 2016. HEDD’s advantage is the in-house developed signature Air Motion Transformer driver.
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© 2021 HEDD Audio GmbH
Heinz Electrodynamic Designs
www.hedd.audio

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