All Harbeth loudspeaker systems are designed and hand-made in England, at the Harbeth factory in Lindfield by the same team. Harbeth is an ISO9000:2008 registered business and has systems, policies and procedures in place from goods-inward inspection through order management and Quality Control. Production log books record the serial numbers and batch traceability details of every Harbeth speaker made since 1986, including the Harbeth BBC LS3/5a.
There is 100% testing of every tweeter, crossover and bass/midrange unit at least once at Harbeth before being assembled into a complete system. It is then tested again as a complete system. We take quality very seriously.
Harbeth Audio Ltd. is formally financially audited. We have an impeccable trading record and are structured for supporting our customers for the long term.
At the concept stage the loudspeaker designer balances the speaker's characteristics for the target music he anticipates will be played on them. If the objective - as at Harbeth - is to make a speaker that is universally accurate to the recording, then the designer must not emphasise or reduce the energy in a specific audio band or the speaker's neutrality will be compromised.
Harbeth speakers are a suitable natural, engaging high resolution sound across all types of music at sensible neighbour-friendly levels. They do not need to be pushed hard to make a wonderful involving sound.
The paramount design objective at Harbeth, above all others, is the avoidance of listening fatigue by skilful design regardless of cost. A truly high fidelity loudspeaker simply cannot and must not sound fatiguing at all, and yet so many home speakers and so-called studio monitors are extremely fatiguing to listen to, to the point of physical pain after just a few minutes of exposure. Their initial promise soon turns to disappointment.
Truly natural-sounding loudspeakers do not exaggerate real-life sound. They just convey the lightness of touch and air of sound, heard live.
Loudspeaker critics from seventy years ago were well aware of listening fatigue and coined terms to describe what they heard, such as disembodied top, chesty, nasal, monkey chatter and so on. They found that music reproduction tended to conceal defects as the listener engaged with the music, but that the reproduction of human voice very effectively exposed acoustic weaknesses. So, we would strongly recommend that if you are curious to explore loudspeakers under demonstration conditions that you replay speech over ordinary speakers. You will hear a far greater range of quirks in their performance than you might expect!
Everything in the universe resonates. Some resonances are rather useful - such as the air mass inside the cabinet acting to permit a good system bass response. Other resonances are not so useful or desirable, such as the sound of knuckles on undamped timber panels.
Researchers have long known that the loudspeaker cabinet can contribute to the overall sound depending upon the panel stiffness, mass and the way it is bonded to adjacent panels. Taming these panel resonances demands great attention to the cabinet construction, and careful adjustment of many variables.
A generation or more ago, BBC research engineers and others proved that relatively thin panels are much easier to damp than conventional thick ones, where no amount of conventional surface treatment would fully suppress latent resonances in the critical middle frequencies. The superiority of carefully damped enclosure walls is part of the magic of the boxless Harbeth sound.
Harbeth have a reputation for sound quality underpinned by the BBC engineering legacy. All Harbeth speakers are designed as serious professional instruments.
Physics dictate that where sound quality is paramount, the drive units need to be of certain size to move sufficient air in order for the listening experience to be life-like. This then sets the minimum dimensions of the cabinet width.
If a no-compromise way could be found to produce the famous Harbeth sound in a different form factor, we would consider it.
Top quality conventional components are used in all of Harbeth's standard circuit boards selected for their actual values, long-term stability, physical size and availability. The component values used are not textbook ones and are tuned specifically to get the best from the Harbeth drive units. They're the result of extensive CAD simulation on the overall performance of the loudspeaker and its amplifier load, in combination with critical listening.
We do not recommend Harbeth users open or modify any part of a Harbeth speaker system because this would invalidate the Warranty. It is very doubtful that the performance could be improved although it could certainly change. From time to time Harbeth may introduce short production runs of advanced versions of its speakers which would permit us to select the ultimate components on a cost-no-object basis.
It is unlikely that mass-market audio quality will ever exceed the standard of the CD, nor, perhaps, does it need to. Vinyl LP, at its best and under ideal conditions, also offers a good sound quality.
It is a matter of debate as to whether the listener can truly benefit from sampling rates above 44/48k even in critical applications, and it is also known that many commercial recordings released in high bitrates (192k etc.) have been upsampled from 48k studio masters with no conceivable improvement in audio quality. Beware!
What do you want the speaker to do for you? Do you want it to spice-up the recording? Give you the immediacy of a front row seat? To project high frequencies with a glass-like cutting edge? Thumping bass? Harbeth is about natural sound and we have achieved that by a unique combination of superior drive unit technology, carefully executed crossover design and carefully crafted and damped cabinetry.
DRIVE UNITS: The Harbeth RADIAL™ drive unit is a masterpiece of clarity and purity of tone. There is no transducer like it - and there is no drive unit that outperforms the RADIAL™ technology because no other manufacturer has comprehensively investigated the matter of what makes a perfect drive unit. Read about RADIAL™ here.
CABINET SYSTEM: Harbeth cabinets are crafted from panels which are internally acoustically damped. This removes the contribution of the box to the sound in the frequency bands where the ear is especially critical.
The 'critically damped' box concept was thoroughly researched by Harbeth's founder when at the BBC, and by other researchers. It is, though, expensive and difficult to implement at a sensible cost, but as with the drive units themselves, Harbeth have mastered the craft techniques whereas conventional enclosures have moved in a direction of low-cost, thick panels which cannot be properly damped.
NATURAL REPRODUCTION: Thanks to our speech-based origins in broadcasting, humans are extremely sensitive to the quality of, and energy distribution through, the all-important 'speech band' (see Q1). This runs from about 100Hz right up (and through) the crossover region and beyond into the high frequencies. The importance of making this band sound 'right' (in side-by-side comparison with the original, live sound) is absolutely critical to the Harbeth soun', and it is the purity and unforced nature of the way we execute that band that sets a Harbeth apart from all others. A Harbeth has a lightness of touch and clarity without harshness - which is, of course, exactly what you would hear at the recording venue.
CROSSOVER DESIGN: Dividing the sonic spectrum (in the crossover) between physically different drive units requires great skill if natural sound is the objective. So, most of our design attention is invested in adjusting the crossover until the pass-band and flare-in/out contributions of the woofer/midrange and tweeter are seamlessly matched. This is mandatory to fool the listener's ear into believing that he's present at the recording, listening to the live first hand.
PLAY AT A REASONABLE LEVEL: Harbeth speakers are designed to sound just like real life when played at a normal, reasonable level. They do not need to be driven hard and unlike many other speakers do not need to be pushed into 'coming alive'. We appreciate how the human ear perceives sound and this knowledge is reflected in the energy balance between the drive units. We have a responsibility to protect listener's ears - and to be good neighbors - and to listening at a normal level whilst creating a wholly satisfying experience.
Loudspeakers present an electrical load to the driving amplifier that inevitably influences the amplifier's measurable and sonic performance. That means that, depending upon the actual loudspeaker and amplifier in question, certain frequency bands may be audibly boosted and others cut, and this will be interpreted as amplifier/speaker combinations having particular sonic personalities. Tube amplifiers and those with output transformers which couple the speaker to the circuitry are likely to perform quite differently depending on the speaker load.
There is a vast selection of amplifiers available each with its own features and fans. Our responsibility is to make sure at the design stage that Harbeth speakers are as benign a load as possible to give you the most amplifier pairing options to the consumer.
An often overlooked characteristic of power amplifiers is component ageing. That implies that the performance of the amplifier will progressively drift from the 'as new' specification with the passing of time, a process accelerated when the amplifier runs hot. Vintage amplifiers can be great fun to own but common sense says that after 25 or more years all electronic systems need specialist servicing to return them to the original specification.
One often overlooked parameter of audio amplifier design is the sensitivity of the input circuitry to the level of the incoming signal. With a phoneo source, the signal is tiny and overload is not likely to be an issue. With a high-level signal such as that from a streamer or CD, if input overload of the speaker-driving audio amplifier is to be avoided, careful scrutiny of its specifications is needed. Better still, to be really sure that the amp is always working in its clean, linear region, its gain structure, especially the circuitry before the volume control, can be audibly explored with a test CD or similar, available on the Harbeth User Group. All that's required is to play the CD source, and adjust the volume control until distortion can be heard, at which point the volume control rotation should be marked as the maximum rotation before the amp is outside its linear region. Once the technical appraisal of the amp's linear operating region is clarified, whether the amp is tube or solid state becomes a matter of personal choice.
Bi-wiring, the provision of more than one pair of terminals on the rear panel of a speaker cabinet, was a fashion in the 1980s and has its fans. The concept is that the signal from the amplifier to the speaker drive units should be sent along one pair of conductors from the amp to the speakers for the low/mid frequencies, and another for the high frequencies. The only Harbeth currently fitted with bi-wire terminals is the Super HL5plus.
The range in performance between so-called monitor grade speakers used in studios is as great as, or perhaps greater than those of domestic speakers. It's a confusing environment where impressing the client with a certain sound is often more important than absolute neutrality. That explains the tremendour range in quality of professional recordings and broadcast sound.
The Harbeth sound is natural, neutral, uncoloured and extremely easy to work with for hours on end at a moderate listening level. Other monitor brands have different characteristics and many boast that they are virtually indestructible when driven by huge amplifiers. Sound quality and immense power handling are uneasy bedfellows.
During any one day, over 20 million UK television viewers will be unwittingly hearing audio mastered on Harbeth speakers, along with millions more listeners overseas.
Yes. In fact, the perfectly integrated mid/high transition and the clean well balanced overall response means that record surface clicks and pops do not draw attention to themselves on Harbeth speakers.
Listening to vinyl on Harbeths is more enjoyable than on conventional speakers. The well-controlled Harbeth mid/top balance is not excited by surface clicks, avoiding listening fatigue.
Loudspeakers, like music, are so personal, so first of all, let's define what Harbeth offers and check it's what you're looking for. Harbeth loudspeakers are precision instruments and are used at home and in professional studios. They contribute little of their own character hence they are of 'low colouration' design with outstanding clarity and naturalness especially in the middle frequencies (where the ear is particularly sensitive). They offer a wide dynamic range and are suitable for all types of music at a sensible replay level.
Alexander Graham Bell discovered at the start of the electric sound age that the 'telephone band' of only about 300Hz to 3kHz is of paramount importance to our ears. Later, when A.M. (long and medium wave) radio was invented, this bandwidth was opened a little for better reproduction of music - but only by a little. So, by definition, the majority of musical energy falls in an audio band that is about as wide as listening to your speakers with the tweeters disconnected. So the defining subjective quality of a loudspeaker system is not at the extremities of the full, wide, 20Hz to 20kHz audio band but somewhere in the middle registers.
Evolution has honed the human auditory system for the interpretation of human vocal sounds, not music. It's an important point. Loudspeakers are coloured to greater or lesser extent, and the use of recorded speech (rather than music) is devastatingly revealing of latent loudspeaker problems in a way that music, unfortunately, is not. You can form much of your final opinion of a speaker's capabilities before you have played the first note of music if you explore its performance replaying male and female speech. You don't have to know the real voice in person, and ideally, you can make your own test tape of a familiar voice, recorded outside on a windless day with a superb microphone - and use that as a test. Replaying speech backwards, or spoken in an unfamiliar foreign language also breaks the emotional associations between the sounds of the words and their meaning and aids analysis.
While there are many examples of technically excellent recordings there are not so many that can be trusted as being truly high fidelity. Many fake the sound by processing, equalisation and the use of a vast number of spot microphones to showcase individual instruments. The concert sound really isn't like that at all: live sound is warm, lush and clean, has a huge dynamic range in reserve, and the instruments intermingle into a floating curtain of sound that is quite unlike most people's impression of home hi-fi. Practically all pop recordings are heavily processed with significant post-recording sound adjustment.
If you play an acoustic instrument, remember that when you play your own instrument that you are listening in its nearfield. This nearfield sound is a much 'harder' sound than a listener in the audience would experience at a distance, and it would be tempting for the musician-listener to select a speaker that mimics that more intense, localised sound.
The piano can be revealing not only of the big details but the micro detail in the decay as the notes fade into the silence in a large hall. But as with so many instruments, much depends on upon the recording. A piano in a small room (or even one in the concert hall with a microphone under the lid, close to the strings), will sound so different to a concert piano, in a big hall with the lid open. Blues, jazz, folk, or 'easy listening' music with simple instruments and vocal is also interesting and revealing of stereo positioning and depth in a different way to large-scale performance with lots happening at once.
Do not use solo pipe organ music to critically evaluate loudspeakers because the harmonic structure of pipe organ seems to be sympathetic to loudspeaker defects and will tell you nothing about the underlying problems (if any) of the speaker in the middle and upper frequencies. Conversely, brass instruments are especially revealing of cone colouration due to their rich harmonics, and showcase the clarity of Harbeth's RADIAL™ cone technology. Conventional cones soften the transients of brass instruments as you will hear for yourself.
A good salesperson will play recordings that highlight and complement (or disguise?) the characteristics of a particular speaker or recording. Do not be embarrassed about bringing a stack of your own CDs or discs with you to the hi-fi shop and be sure to make an appointment in advance. You will need lots of time, and a good dealer will expect this, and make a date for you.
Above all guard against being impressed because truly natural replay sound is not 'impressive'. It has a lightness of touch and a freshness which over good loudspeakers hangs like a curtain of sound and does not push the performers onto your lap. Excellent loudspeakers are subtle and impressive in the way they reproduce the small details, the microtones in music, and not by how loud or attention-grabbing they are. One of the exceptional characteristics of Harbeth's RADIAL™ cone technology is that no matter what they are tasked with reproducing, they don't fog over the details as conventional diaphragms do - listen out for that.
You can find more about the recording process and a detailed analysis of the typical subjective characteristics of hi-fi and studio monitor loudspeakers in our blog post, Listening to loudspeakers. Why not keep a printed copy to hand when you evaluate hi-fi speakers?
This question is ambiguous. The physical electrical filters employed in the crossover are not text book, and are in the range of 12-18dB per octave in the crossover region. The contribution of sound waves at the listener's ear (or measurement microphone on axis) throughout the crossover region is of around 18-24dB per octave. The electrical filters are well damped, and necessarily employ numbers of components to be sure that the drive units are all working perfectly in their optimum quality range.
The specialist hi-fi cable industry offers the consumer a vast array of solutions for connecting audio equipment together. This is surely a very good thing.
Ignoring cosmetics, there seem to be two main approaches to the design of speaker cables. One approach involves the deliberate manipulation of the measurable physical properties of the cable (resistance, capacitance and inductance) to alter the load that the amplifier sees. This maximises the contribution of the cable to the overall sound by introducing the cable as a filter element to the signal chain. Inevitably, the cable length will become a factor in this filter action, so the sonic results are rather unpredictable. Such a cable may well 'spice-up' the sound, but is that the correct approach in a high-fidelity sound system?
The opposite cable design philosophy holds that the cable be designed to minimise its contribution to the overall sound, by controlling, and minimising, the basic physical characteristics of resistance, capacitance and inductance. This seems a sensible goal to aim at in an audio listening system that is designed to be as neutral as possible and side-steps cable length as another variable. As far as the BBC are concerned, the Harbeths installed there are wired with modest conventional cable and that seems good enough for their professional purposes.
If you desire to experiment, have a long-term reference to fall back on such as humble 79 strand basic cable or something similar sold for electrical appliances around the home. Work with your dealer to find the best solution for your unique set-up.