HEDD Bass 08 - User review - Gearspace.com
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HEDD Bass 08
5 5 out of 5, based on 1 Review

Fully-featured with useful controls...coherent, full-bodied soundstage

4th June 2021

HEDD Bass 08 by Arthur Stone

HEDD Bass 08

Introducing: Gearspace recently reviewed the new Mk2 version of the HEDD Type-20 3-way studio monitor; in addition, the HEDD BASS 08 subwoofer to create a 2.1 system.

The new HEDD Audio BASS 08 and larger BASS 12 offer similar onboard electronic wizardry (A/D conversion and DSP) as the Mk2 Type- monitors. The BASS 08 and 12 are the first HEDD subwoofers and are compatible with the Mk1 monitors also.

I never really trusted subwoofers before. Something disjointed and 'nearly there' about the soundstage. The 08 changed my mind.

What I'd expect – or hope for – would be a more sophisticated, fuller bass representation, and an improvement in the performance of the main monitors (as they have less bass work to do). In my experience, if the crossover isn't good and the sub/monitors don't 'gel' then there is a hole or wide slot in the soundstage...low down near my ankles....a sense of disconnect.

The 2.1 combo of HEDD Type-20 mains and BASS 08 sub had a few things going for it: same manufacturer/range meaning a compatible crossover and powering; the Linearizer to optimize the signal for the subwoofer; and the rear panel dials to control room position/time delay. Each monitor also has the option for open- or closed-ports.

To cut to the chase, the HEDD Audio BASS 08 subwoofer scores full Gearspace points; professional gear; fully-featured; ease of control, connectivity, and fine-tuning; and a perfect sonic compliment to HEDD's main monitors at a price that doesn't break the bank.

BASS 08 signal path: Whether inputting an analogue or AES digital signal the path goes through the DSP section; essentially the BASS 08 is a digital monitor: not just digital amps and crossovers but full analogue-to-digital conversion and processing at 96kHz/32-bit.

Purists may grumble about the lack of analogue-only signal path and inclusion of DSP but this is a mature technology now and there is no negative sonic indication of a subpar digital process, in fact there are advantages over analogue particularly evident with subwoofer frequencies: super-low distortion; fast response; clean crossover; low noise floor...also low physical weight.

The digital features can also be updated via an Ethernet connection to an app, either to an online update file or an offline file. The firmware update process is quick and straightforward.

Rear panel controls: High-quality, feelgood dials. Good ergonomic layout with plenty of finger room. The set-up makes it a bit easier to manipulate the controls from an awkward position than other subs I've used.

From top left:
Vol dial adds or cuts up to 12 dB of output gain;
Linearizer (off/on/3rd blank);
CoP ported or closed;
Satellite Offset of +/- 2 metres to align with main monitors;
Crossover frequency (40-200Hz);
Low Frequency Range;
Analogue/AES input selector;
Input Sensitivity variable from -10 to +4dB;
Phase position.

Closed-or-Open (CoP) port baffles: Inserting the two circular baffles (plugs) into the BASS 08 (and 12) changes the character and response to that of a sealed cabinet; a rear panel dial selects between Open (ported) or Closed (sealed) to compensate and the DSP maps the signal to the new configuration. Tighter, tubbier bass or a slightly more laid back, subdued response.

Traditionally the use of sealed or ported cabinet designs have been room- and position-dependent e.g. ported designs, especially front-ported, have been better suited to a position close to the rear wall whereas sealed cabinets can resonate with the wall and perform better free-standing with some air around them.
CoP offers more than just this practical room-dependent application: sealed or ported offers a different dynamic and tonal response that can be an artistic decision for the listener. In use, both settings worked in my room, the difference being the angle of insight into the mix.

***Sorry, forgot to take baffle photos: they are high-quality rather than cheap plugs, similar to the baffles pictured below on the Type-20 Mk2's below but circular rather than oval.

The Linearizer: The short story is that each model of monitor (from any brand/manufacturer) has imperfection in playback (caused by the physical components): bass frequencies are subject to a longer time delay (milliseconds) than higher frequencies, and this difference across the frequency spectrum leads to out-of-phase sonic artifacts (disjointed soundstage; uneven response; etc.).

Each monitor has a unique 'phase response curve' and this can be measured in a anechoic chamber.

The Linearizer (a digital signal process) creates an inverse filter of the 08's phase response curve, passes the incoming audio through the filter, and this corrects the monitors imperfections on playback. The process results in optimal phase coherence across the spectrum; with frequencies aligned; leading to a detailed soundstage true to the source.

The monitor is also working at better mechanical efficient as it is not receiving conflicting signals at the same time e.g. signal to push speaker out and in at same time. This last point is important for subwoofers, in this case the HEDD Audio BASS 08, which is unique in offering the Linearizer feature in a subwoofer. A first.

Price: $1200 US/ £920 (inc. VAT) UK/ Euro 999


Tech Specs:
Woofer (honeycomb diaphragm): 8" (2" voice coil)
Frequency response (-3dB): 24-80 Hz (var)
Variable upper frequency limit: 40-120 Hz
LF range (-3dB): normal/extended: 24Hz/20 Hz
LFE function (LowPass filter and +10 dB gain): LP 200Hz / +10 dB
Input 1: analog stereo (2 ch) / Impedance: 2 x XLR / 22kΩ
Input 2: AES "in"1 x XLR
Output: AES "through" 1 x XLR
Output to satellites stereo (2 ch) highpassed @80 Hz L/R 4th order
Satellite offset @ANALOG OUT ± 2m, in .5 m steps
Input gain ±12dB
Input sensitivity: 0 dB = 90dB SPL/1m: -10/-4/0/+4 dB
HEDD Lineariser®, disengageable, delay: 30 ms
Phase switch:0/90/180/270°
Power Amplifier /Universal Mains 110-240 V: 300 W ICEpower
AD/DA Conversion: 96kHz/32bit
SPL max @ 1 m (half space): 105 dB SPL
Cabinet with satin lacquer finish: black
Dimensions (H x W x D): 392 x 290x 400 mm
Weight: 17kg
Warranty: 2 years

More Bass Sir? The main technical differences between the BASS 08 and the BASS 12 are the larger 12” speaker and 2.5” voice coil (against the 08's 8” and 2” respectively); a frequency response from 20Hz (the 08 24Hz); a 700 watt ICE power amp (vs the 08's 300); 115 dB max SPL at 1m (vs the 08's 105); and a substantially larger physical size and 20kg extra weight over the 08's modest 17kg.

HEDD have specc'ed the 08 and 12 well for their potential markets and rooms: the 08 is ideal for the smaller room or home/project studio. Despite living in an apartment I didn't have any concern (or guilt) about using the sub. No bass was wasted outside of the soundstage. The 08 reacted well with the room's modes and nodes, no doubt assisted by the Linearizer.

The 2.1 combo of the HEDD Type-20's and BASS 08 provided all the power and level I needed for safe continuous listening levels in a nearfield position (6' triangle), plus enough juice for tracking with instruments outside of the mix seating position, Two 08's would be an option if I had a larger room...or the BASS 08 and Type-15 2-way monitors.

The BASS 12 is considerably more powerful (on paper) but I didn't feel I needed that extra at near-to-midfield position and the 08's 300 watt amp segued well with the Type-20's 300 watt per speaker. Having not used the BASS 12 I can't make any recommendations, for example, they may be better matched with the Type-30's, but, for sure, they share the BASS 08's superb sound, build-quality, and features at a reasonable price point.

In Use: I updated the firmware: an easy online process via a HEDD app or using an offline file linked by Ethernet to each monitor.

The digital pathway seems to only bring benefits; I didn't hear any giveaway sonic artifacts of a digital character. The sound appeared as 'analogue' but without the usual 'analogue' side-effects such as hum, buzz or a sense of potent electromagnetic energy.

From the monitoring seat, with the 08 sub at my feet, I was unable to tell if the unit was powered on (apart from the signal LED) or that the wonderful low bass was coming from it. Also it is an even frequency response across the spectrum with no dips or bumps at the crossover: vibe without hype. Seamless.

The 08 is noiseless; only the bass sounds appear – no sense of weighty ambience or smudged detail. This sense that the soundstage is dissociated from the monitors is a characteristic of HEDD gear.

In the Linearization process the low frequencies the subwoofer deals with can be delayed from 200-500ms and the satellite speakers around 10-20ms (as the higher frequencies are faster).

The solution to this time differential is to delay the satellites: this is the first time a sub and satellite system can be phase-aligned. This assists in creating a seamless crossover point and reduces boominess and unwanted artifacts. I left the Linearizer on; the main sonic difference was a tightening of the bass with more detailed transient information and this upper detail segued well with the sound from the main monitors (also Linearized).

Without the Linearizer the sound is perfectly acceptable – musical and enjoyable but lacking the technical detail with Linearizer engaged. Having the ability to bypass the Linearizer offers zero-latency monitoring for tracking or time-critical workflow.

In addition the rear panel Satellite Offset control allows the physical position between subwoofer and satellite speakers to be compensated for (up to a distance of +/- 2 metres in 0.5 m steps – an approximate time window of 12 milliseconds). I positioned the BASS 08 close to my feet at mix position so didn't need it but it's a handy feature.

I felt comfortable and confident making decisions based on the 08; the sound is accurate and pleasurable to experience and this removes obstacles to workflow and creates a positive feedback loop for music production or leisure-listening.

Conclusion: The BASS 08 is more than just a subwoofer (the traditional bass reinforcement perspective) and more a hardware unit that glues the soundstage together and extends it.
Everything one could wish for: seamless, un-hyped, quiet self-noise. The reproduction of sound is very accurate. A pleasure to use and experience. I think the best compliment I can give the HEDD Audio BASS 08 is that it disappears and a coherent, full-bodied soundstage remains.

Gearspace Points.
Sound quality: 5/5 Exemplary. Quiet self-noise; perfect imaging in the soundstage. No hype.
Features: 5/5 Fully-featured with useful controls.
Ease of Use: 5/5 Small learning curve with the controls. Easy set-up; fine-tunable. Seamless sonic integration with the main monitors. Physically light and easily manoeuvrable (for a sub).
Bang-for-buck: 5/5Very good. For the quality of the product and its capability.

Attached Thumbnails
HEDD Bass 08-08bottom.png   HEDD Bass 08-08comp12.png   HEDD Bass 08-08dial.png   HEDD Bass 08-08panel.png   HEDD Bass 08-08rear.png  

HEDD Bass 08-08rearpanel.png   HEDD Bass 08-08t20baffle.png   HEDD Bass 08-08unique.jpg   HEDD Bass 08-08update.png   HEDD Bass 08-08woofer.png  

Last edited by Arthur Stone; 4th June 2021 at 05:55 PM..