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The Harbeth User Group is the primary channel for public communication with Harbeth's HQ. If you have a 'scientific mind' and are curious about how the ear works, how it can lead us to make the right - and wrong - audio equipment decisions, and about the technical ins and outs of audio equipment, how it's designed and what choices the designer makes, then the factual Science of Audio sub-forum area of HUG is your place. The objective methods of comparing audio equipment under controlled conditions has been thoroughly examined here on HUG and elsewhere and should be accessible to non-experts and able to be tried-out at home without deep technical knowledge. From a design perspective, today's award winning Harbeths could not have been designed any other way.

Alternatively, if you just like chatting about audio and subjectivity rules for you, then the Subjective Soundings area is you. If you are quite set in your subjectivity, then HUG is likely to be a bit too fact based for you, as many of the contributors have maximised their pleasure in home music reproduction by allowing their head to rule their heart. If upon examination we think that Posts are better suited to one sub-forum than than the other, they will be redirected during Moderation, which is applied throughout the site.

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{Updated Oct. 2017}
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The role of the loudspeaker

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  • The role of the loudspeaker

    ... to inflate the room with sound ....
    Alan A. Shaw
    Designer, owner
    Harbeth Audio UK

  • #2
    ..to disappear..

    Comment


    • #3
      To let us hear our Hi-Fi system. No matter how good or expensive a system is, it's nothing without speakers.

      Comment


      • #4
        As you may have read here, the function of the loudspeaker is, objectively, to ....create sound waves in the listener's room.

        Agreed? Any other objective purpose you can think of?

        Loudspeakers exist to modulate the ambient air pressure in the listener's room.

        Modulate = increase or decreasing something with respect to time

        Air pressure = is what we measure with a barometer. It's usually expressed in millibars, or these days in Pascal (Pa). Air pressure varies with height above ground, and it's that fact which allows aircraft to know their altitude. See here.

        Taken together then, the above highlighted sentence means...

        'The loudspeaker is a device placed in the listener's room that acts as an air pressure pump. Although the ambient pressure in the room (at ground level) is static (only varying over hours or days according to the local weather), when the loudspeaker starts to play it increases and decreases the air pressure fraction of second by fraction of second in the vicinity of the loudspeakers according to the music. Our ears/brain are desensitised to the ever-present ambient background air pressure, but good at sensing pressure modulation of the constant static air pressure, as caused by the loudspeaker, and we call that experience 'sound'.
        That's all we need a loudspeaker to do for us.

        Why are there then thousands of different variation on the theme of loudspeaker?
        Alan A. Shaw
        Designer, owner
        Harbeth Audio UK

        Comment


        • #5
          I guess there are many speaker designs because it is actually very hard to make a good speaker. Even the best ones like Harbeth are far from perfect, so they are not an effectively homogeneous commodity like the electronics have become (even if boutique electronics manufaturers try to convince us otherwise). Also, a speaker's performance is crucially influenced by the room, and not all rooms are the same. Finally, good speakers are (should be) by far the most expensive part of the chain.

          Comment


          • #6
            Originally posted by A.S. View Post
            Why are there then thousands of different variation on the theme of loudspeaker?
            Because no method of pumping air in the listener's room is perfect, and in consequence there is no ideal loudspeaker.

            Comment


            • #7
              Originally posted by Milosz View Post
              Because no method of pumping air in the listener's room is perfect, and in consequence there is no ideal loudspeaker.
              I'd say that sounds like logic. It must be correct.

              Let's just think about a typical 'hi-fi' speaker for a moment. We accept that the basic function is to modulate (pump up and down) the air pressure in the room. Humans then experience 'sound'. But forget everything you know about loudspeakers, and imagine that you are a passing alien who sees a loudspeaker for the first time.

              What do you notice in the arrangement of moving parts in the loudspeaker air pump?
              Alan A. Shaw
              Designer, owner
              Harbeth Audio UK

              Comment


              • #8
                ... to deliver recorded sound as good as possible to the listener ...
                Last edited by mactrix; 09-09-2017, 09:08 PM. Reason: replaced "music" with "sound"

                Comment


                • #9
                  I don't think that the primary role of the loudspeaker is necessarily related to music, audio, pleasure, or similar.

                  The loudpseaker is necessary on Earth, with an air atmosphere, to pump air pressure up and down in the locality of the speaker. That has no automatic association with speech, audio, music or even quality. The same loudspeaker transported into the vacuum of space would be uttery useless, because there is no air, and hence no air to pressurise. Hence, logically, there can be none of what we humans call 'sound'.

                  Evolution has taken advantage of the static omnipresent pressure of the earth's atomophere as it envelops humans, to develop a personal inbuilt system of detecting tiny variations - modulations - of local air pressure around the head of the listener. The detectors are called ears. All the loudspeaker has to do - and exists for - is to pump air pressure. Everything else that it does or does not do is secondary.

                  Let's take this analysis step by step, as Prof. Faraday would. My question in post #7 above was what do we see when we look at a typical hi-fi speaker? How are the parts visually arranged? Describe exactly what you see.

                  This is not a trick question but it has very wide ramifications.
                  Alan A. Shaw
                  Designer, owner
                  Harbeth Audio UK

                  Comment


                  • #10
                    When I look at a typical hi-fi speakers and equipment, then most either don't look nice or they are porn. They look like foreign body in the living space.

                    They are either cheap mass products or intended to impress the visitor with obscene design (horns, oversized, polished, phallus symbols, silver cables, tubes).

                    Comment


                    • #11
                      Originally posted by mactrix View Post
                      When I look at a typical hi-fi speakers and equipment, then most either don't look nice or they are porn. They look like foreign body in the living space.

                      They are either cheap mass products or intended to impress the visitor with obscene design (horns, oversized, polished, phallus symbols, silver cables, tubes).
                      Please, with respect, I am not asking for a subjective opinion. I'm asking for an observational report in the style that of one of the greatest observationalist scientists we have seen, Prof. Michel Faraday, would write. Would he have written the above comment? Respectfully, I don't think so. I'm not interested in personal opinion here, no matter how much I may agree or disagree. We're just after observational reportage. Facts, in other words. So we can build a reliable lexicon independent of personal preferences.
                      Alan A. Shaw
                      Designer, owner
                      Harbeth Audio UK

                      Comment


                      • #12
                        Example of Prof. Faraday's lucid investigatory style from his diary of March 1851 (and a lesson to us all in clarity):

                        1685*. Again, placed a piece of soft iron opposite the pole of a bar magnet a foot long, an inch broad and 0·4 thick (the figure is to a scale of about one half); and then placing paper over the bar and magnet, sprinkled fine filings on and observed the lines depicted. It was beautiful to see how they flowed into the iron at the end near the magnet and how they flowed out again at the further part from a comparatively much larger surface— and also to see the concavity of the lines outside the iron near the equatorial part of it, shewing the double curvature— and the beautiful character of the streams of force into the air or space from the further part.
                        This is the sort of contribution to debate that endures. No complex numbers. Just a picture that is drawn in the reader's mind. Not an explanation of the physical process; an observation of it.

                        So, back to my question from post #7.
                        Alan A. Shaw
                        Designer, owner
                        Harbeth Audio UK

                        Comment


                        • #13
                          Ok, let's have a go. (Don’t laugh):

                          In purely descriptive (and literal) terms... we notice a conical surface made from plastic or cardboard material and suspended by a rubber surround over a purposely created magnetic field capable of imparting controlled vibrations upon the cone via a coil attached to its base. All this is hidden from the eye by something called a ‘dustcap’ that forms the cone’s convex bottom and effectively seals in all the parts behind itself.

                          Thanks to the airtight nature of the cone material, its thinness and rigidity, and also to the high flexibility of the rubber suspension, the said vibrations can be optimised to the benefit of the speaker’s efficiency.

                          Comment


                          • #14
                            A* answer. Nothing to laugh about there. Great. That's what my granddaughter would see.

                            Originally posted by S Magus View Post
                            In purely descriptive (and literal) terms... we notice a conical surface made from plastic or cardboard material and suspended by a rubber surround over a purposely created magnetic field capable of imparting controlled vibrations upon the cone via a coil attached to its base. All this is hidden from the eye by something called a ‘dustcap’ that forms the cone’s convex bottom and effectively seals in all the parts behind itself.

                            Thanks to the airtight nature of the cone material, its thinness and rigidity, and also to the high flexibility of the rubber suspension, the said vibrations can be optimised to the benefit of the speaker’s efficiency.
                            So, if we separate the observation from the deduction (which requires far more insight than you could possibly have looking at the speaker plonked in front of you as a passing alien would see it), and we have:

                            we notice a conical surface made from plastic or cardboard material and suspended by a rubber surround....
                            That's the observation I'm after.

                            I think we could expand your observation of a typical hi-fi speaker a step or two further. How about if we add ....

                            ... we notice a box comprising solid panels forming a front, a back and a top and bottom. On the front surface we observe a conical surface made from plastic or cardboard material and suspended by a rubber surround. In addition we observe a smaller conical surface....
                            How does that seem to you?
                            Alan A. Shaw
                            Designer, owner
                            Harbeth Audio UK

                            Comment


                            • #15
                              Imagining myself as an passing alien when I look at my speakers, I see a mute symmetrical pair of rectangular boxes with purposefully placed, round, concentric circles of synthetic membrane like surfaces of two sizes, mounted vertically, a smaller round membrane above a larger round membrane placed on the front surface of each box and flush mounted secured with screws in a metal frame. Both boxes are a certain distance apart and level both vertically and horizontally, again symmetrically, as well as facing in the same direction.

                              The boxes are of solid construction, all 4 sides are solid planes apart from the front surface with the convex concentric membranes the larger one has a smaller concave cupola of the same material in its centre, while the smaller membrane has a convex nodule protruding from a finely meshed patterned membrane. The taut membrane material is both fragile and resilient. The opposite face of the box has a circular plastic panel from which the lugs protrude, into which the wires are held in place by a screw like mechanism on each of the lugs. One lug is red in colour, one lug is black in colour on each box.

                              Zork is calling I must make my way back to the ship as the invasion of the Mngpphy star system continues apace.

                              Comment

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