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Thread: Confused by loudspeakers? Read on ....

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    Default Confused by loudspeakers? Read on ....

    Evaluating loudspeakers by listening and finding the best one for your needs takes time and skill. Here we give you some tips. [We have covered this in thousands of posts across the HUG: here is the quick guide.]

  2. #2
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    Default Introduction: Listening to loudspeakers

    In an interesting recent post a new user commented that he'd been living with a pair of speakers for nearly thirty years. Exchanging these for any speakers regardless of brand or model after such a long familiarisation is the same as separating from your long-time life partner and starting all over again. Some will quickly adapt whilst others will find the transition confusing and disturbing. Given enough time, most will adapt. And just as with the human heart, time heals and both it and the audio memory heal and reset themselves.

    I know that we've touched on the vital core subject of listening to speakers many, many times in numerous posts scattered across the Harbeth User Group. I many respects it is the most important subject. I've been curious about the sound that loudspeakers make since I was a teenager. The one thing I didn't inherit (or more accurately, contract to buy) from Harbeth's founder Dudley Harwood, was formal expertise in evaluating the sonic character of loudspeakers. I knew the concept, I'd read the erudite papers but I didn't know how to actually sit in front of a speaker and deconstruct what I was hearing. That process can no more be hurried than developing a nose for whisky or perfume. It just needs a curiosity and plenty of time.

    Well, luckily I had the time and interest. I'd not expect you to have either. So what I want to do is to pull together the essence of what I've learned about 'tasting' loudspeakers in as readily accessible form as I can. This is only my methodology and experience; you should develop your own way to attack this subject. And once you have worked that out, hone it and refine it. It's a good skill to have.
    Alan A. Shaw
    Designer, owner
    Harbeth Audio UK

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    Default 1. A loudspeaker creates an illusion ....

    In my post here I mentioned how a loudspeaker createdsan illusion in your brain of being in the company of real musicians. We willingly fall into the trance that we're 'really there' despite the fact that our loudspeakers (boxes) are reproducing musical instruments (boxes) recorded in a studio (another box) and played back in our listening room (yet another box). Somehow our brain can hear through the intermediary steps and take us directly to the musicians.

    But have you ever wondered if a animal would similarly be able to jump the box-in-box of the reproduction chain and also be seduced by ghost of the original sound? Or to their ears would it be apparent that the at-home listening experience was entirely different and unconnected to the real life sound? It would depend upon the audible cues that humans and animals use when creating the illusion in their brains. There may be commonality - or there may not.

    To rework some thoughts from my post mentioned above:

    I really can understand the tricks that ones audio memory can play on you. But the core issue is that audio reproduction at home is nothing more than an illusion. Whilst you listen you (hopefully) allow yourself to be drawn into an enjoyable trance, overriding the logical part of your brain which says 'these performers just can't be here in front of me, in my room!'.

    INHO to begin to make any sort of credible comparison between two speakers that create an entirely different listening experience you'd need a whole vocabulary of words to describe to yourself what you are hearing. How the colours in the new dream differ from those of the old one... [all speakers] are wrong; [all speakers] are right. Neither is reality - both create an illusion.

    The really challenging task, even for someone who works on loudspeakers as a designer, is teasing out level differences from coloration or quality differences when listening. They may in fact have the same sort of sonic signature. But the designer can play around with the levels, up or down, but he's really stumped by latent coloration issues. Even an experienced listener may mistake one for the other....
    Alan A. Shaw
    Designer, owner
    Harbeth Audio UK

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    Default 2. Is there a perfect loudspeaker?

    No. It entirely depends upon what you expect the loudspeaker to actually do for you. If you want to project a voice across a football stadium, you'd be advised to consider a speaker with a dominant midrange and no bass or extreme top. What I'd call a 'hot' sound. If you want to provide background music in a restaurant, then the very last thing the diners would want is a hot midrange! They'd appreciate a depressed, distant midrange, little top and a warm, soft bass. And played very quietly too. This applies to the professional application of loudspeakers too. PA speakers find favour with groups because they deliberately introduce coloration to give a certain sort of vocal or guitar sound.

    Many pop bands of the 60s and 70s freely admitted that 'their' sound was significantly the sound of their PA speakers - brands like Marshall exemplified this. So the concept of a perfect speaker is as ludicrous as the perfect motor car. Fuel efficiency may be of paramount importance to a Ford driver and an irrelevance to an Aston Martin driver. Both users are absolutely right. So it certainly is 'horses for courses' when considering loudspeakers. And we at Harbeth would never waste the time or energy persuading someone that our speakers were the ultimate.
    Alan A. Shaw
    Designer, owner
    Harbeth Audio UK

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    Default 3. A lexicon of words to describe a loudspeakers personality

    Perhaps we should standardise on a dictionary of descriptive terms that cover the sonic personality of loudspeakers we may encounter.

    Did you know that at least as far back as 1937 in the pioneering days of quality loudspeakers, our forefathers were perfectly aware of most of the issues that still bedevil today's loudspeakers. The adjectives they use we still use to describe excessive or deficient energy in different frequency bands.

    Attached is a scan of the original 1937 (UK) GEC Research Laboratory blueprint document (the only way of making a copy, long before the photocopier was invented) from my archive. Nothing has changed in over sixty years of loudspeaker development. The speaker industry should not be proud of that. Consider that this document was written two years before the start of WW2, in the days of the shellac 78 record, and about ten years before magnetic tape was invented. In other words, the limitation of the reproduction chain even then had been identified as the loudspeaker - as it still is. By a very large margin.
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    Alan A. Shaw
    Designer, owner
    Harbeth Audio UK

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    Default 4. How humans sense the world in which we live

    A creatures that is able to gather useful information about its environment is one better able to take advantage of the environment. And the primary evolutionary drive of all living creatures is to reproduce. The food chain means that one living organism may consume another for food. Hence, avoidance of predators is of paramount importance if you want your species to thrive and reproduce.

    All human senses have their origins in tipping the balance of survival away from predators. Our ears in particular, with their strange external flap and organ of hearing buried at the end of the ear canal inside the skull, have been optimised to hear a predator approaching. They have not been especially refined for speech or music, because in the evolutionary time line, speech and music are very recent events: too recent to have had an impact on the million-year development of the human hearing system.

    Attached a picture of youngest son David's ear.

    We should consider why evolution has honed the ear/brain as it has. Three things strike me:

    1) The physical external (and I assume internal) apparatus of the ear seems to be common to many animals; a cat, dog, tiger and man all seem to share a basic design. On the basis of Darwin's selection of the fittest this common mechanism must serve evolution well, this is, it provides an adequate advance warning system of predatory danger. Any alternative and lesser acute or useful hearing system would have been weeded out by evolution because, quite simply, if its owner was eaten because it didn't hear approaching danger then such a design would be an evolutionary dead-end (literally).

    2) It follows that this basic system must have reached a point of development far back in history before the branching of species into the evolutionary tree we're familiar with now. And since that point there must have been very little development of the ear.

    3) None of the other species sharing the same auditory system speak or create and listen to music. So musical abilities - which we believe only date from about 35,000 years ago - are certainly not what the ear apparatus was designed or optimised for: music (even speech) is a secondary and rather specialist application for which there is no specific adaptation in the mammalian ear it would seem.
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    Alan A. Shaw
    Designer, owner
    Harbeth Audio UK

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    Default 5. The limitations of our senses

    There are three reasons that scientific measuring instruments were invented:

    1) The acuity of our senses varies with age, health and disease. A very young person or an old person will sense differently to someone in middle age. A child may not feel cold; and elderly person may be unable to move unless the room temperature is greatly elevated, so much so that a middle age person is stifled.

    2) The performance of our senses somewhat depends upon their training through repeated use. A perfume chemist has a highly developed sense of smell and can detect subtle fragrances present in very low concentrations that an untrained observer is unaware of.

    3) Our senses are good at making reliable side-by-side comparisons but very poor at making time-range comparisons. Take a look at the two colour swatches AS THUMBNAILS JUST AS YOU SEE THEM BELOW THIS TEXT (don't click on them yet) - are they exactly the same colour or not? Difficult to say isn't it. But how about if I showed you only one red swatch now, and in ten minutes or a week or two showed you the other? What then? Or if you hover for a few seconds over one then use the mini-viewer to make an instantaneous switch between them. What now - are they the same colour or not? Are you more confident at judging when the comparison has only the shortest time-gap?

    This demonstrates why scientists invented instruments. Even the simplest instrument - a ruler - is necessary because we must compare the unknown length against a known length to determine the unknown length with precision. No human is capable of drawing exact linear or angular dimensions with precison. Or consider temperature measurement - the thermometer removes the inevitable personal variances between observers. Or hertz which standardises frequency and pitch. Or the decibell, loudness. Our scientific world is underpinned by standards and if we had perfect objective sensory ability, we would not need instruments. We would be the instrument. Science is about removing the variability due to the observer from the equation. Non-science is about promoting the opinions of the uncalibrated observer at the expense of experimental controls.
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    Alan A. Shaw
    Designer, owner
    Harbeth Audio UK

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