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Thread: Harbeth SHL5 specific

  1. #21
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    Default Re: Harbeth SuperHL5 specific

    Leo: for security reasons this is not a question that should be directed at the User Group. Please contact the factory and give then time to scrutinise the records - they are busy.
    Alan A. Shaw
    Designer, owner
    Harbeth Audio UK

  2. #22
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    Default High Powered Amps with Super HL5

    In a magazine review for the Super HL5 the reviewer mentioned using 400w monoblock amplifiers. Knowing that the HL5's need something like 10% of this power to sound grand, at what point do very high-powered amplifiers cause damage to the speakers? Would a 500w @ 8ohms amp cause damage to the HL5's, for example?

  3. #23
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    Default Re: High Powered Amps with ..... anything

    Quote Originally Posted by ACF
    Would a 500w @ 8ohms amp cause damage to the HL5's, for example?
    I'm glad this old chestnut has resurfaced to have the opportunity to cover it again (it was on the old Smartgroups).

    First, how can we put this into proportion - it's difficult to imagine a Watt isn't it. Well ..... not really. A Watt is a unit of energy. That's all we need to know. So how much is 50W or 500W? Well, if you hold a 50W light bulb in your hand you're experiencing the heating effect of 50W since the amount of that energy that is radiated as light is miniscule (which is why regular bulbs are such an environmental curse).

    How about 500W? OK, that's ten 50W bulbs all working together. Now, could you comfortably hold a working 50W bulb? Maybe - maybe - for about 20 seconds. How about 500W? You'd be mad to try.

    When the energy reaches the speaker where does it go? About 99% is wasted as heat: it does nothing useful in getting sound to your ears. Where does the heat go: mainly in the voice coil. And the voice coil is bonded to the cone, which is made of plastic. And what do you think 495W (500W x 99%) of energy does to the cone? It melts it. Simple as that. And very quickly too.

    Example: (click on picture at the bottom of the page to see the frightening effects of too much power: the hot, sharp edged voice coil former has softened then cut its way through the cone just as a hot-wire polystyrene cutter through a ceiling tile) http://www.harbeth.co.uk/sales/servi...ares/index.php

    Hope that clears up the mystery!
    Alan A. Shaw
    Designer, owner
    Harbeth Audio UK

  4. #24
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    Default Re: High Powered Amps with ..... anything

    The specification of M40 states that it can handles 200W programme material, does it means it can max convert 200W input energy into sound pressure? Anything beyond that will be dissipated as heat?

    Also the product brochure states M40 has sensitivity 84dB @ 1W. Given every double up power can increase 3dB in loudness,
    87dB @ 2W
    90dB @ 4W
    93dB @ 8W
    96dB @ 16W
    99dB @ 32W
    102dB @ 64W
    105dB @ 128W
    108dB @ 256W

    Does it mean that the maximum loudness M40 can produce is somewhat around 105-108dB?

  5. #25
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    Default Re: High Powered Amps with ..... anything

    Before we drift down this road - because needless to say I've only touched on the subject in my previous comments and I have a feeling I gave further information here not that long ago - what other extremely limiting factors do you think could govern the maximum power input to (and sound pressure from) a speaker system?
    Alan A. Shaw
    Designer, owner
    Harbeth Audio UK

  6. #26
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    Default Re: High Powered Amps with ..... anything

    Alan,
    I guess the max power handling depends on the following factors:

    Magnet strength
    Cooling efficiency of motor structure
    Moving mass of voice coil

    My guess is just based on some marketing claims from other manufacturers saying those are the factors for their high power handling. Interest to learn more on the voice coil and magnet detail of Harbeth unit other than the RADIAL material.

    Kevin

  7. #27
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    Default Re: High Powered Amps with ..... anything

    Well almost. We are exploring the whole issue of a speakers efficiency. We mean by 'efficiency' how effectively it converts electrical energy into sound. I stated earlier that about 99% of the electrical power arriving at the speakers terminals never becomes sound, it is wasted as heat. So, the electro-acoustic efficiency of a typical speaker system is about 1% - extremely poor.

    Then we moved to look at power handling - which is not the same issue at all. Low efficiency does not necessarily imply low power handling, but it often is.

    You said that max power handling depended upon:

    1) Magnet strength ---- no, relates to the conversion of electical input into sound not power handling

    2) Cooling efficiency of the motor structure --- agreed, relates to the burn-out limit of the voice coil

    3) Moving mass of the voice coil --- no, almost irrelevant in (Harbeth-like) bass unit, no significant effect on power handling or efficiency.

    So, only 2) relates to the maximum power handling.

    So where does that leave us then? There are seriously significant element in the efficiency/loudness equation. What do you think they could be? Clue: think about elastic bands and also about pendulums.

    Please also look at: http://www.harbeth.co.uk/usergroup/s...?p=866#post866
    Alan A. Shaw
    Designer, owner
    Harbeth Audio UK

  8. #28
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    Default Re: High Powered Amps with ..... anything

    I have thought of cone thinness, elasticity of rubber surround and crossover complexity. But I am not sure they are relevant to max loudness or/and sensitivity?

  9. #29
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    Default Re: Roll up! Sensation! "Puny little Driver fights The Atmosphere".

    Quote Originally Posted by kevint
    I have thought of cone thinness, elasticity of rubber surround and crossover complexity. But I am not sure they are relevant to max loudness or/and sensitivity?
    Well, let's review what sound waves really are. A sound wave is nothing more sophisticated than a localised variation in the atmospheric pressure in the vicinity of the source (i.e. the drive unit).

    If this pressure modulation were not (very) local then somone playing a speaker in London would be audible in Beijing.

    About the atmosphere: it has a pressure on the entire surface of the earth that's fairly constant. It varies (predicatably) with height so up a mountain the pressure is lower. (Thought: that implies that a speaker played up a mountain would be even less efficient than on the ground: it it were a battery operated ghetto blaster, those batteries would run down far quicker up there as the volume control would have to be turned up further to produce the same loudness).

    Now, let's think about the woofer. It has an 8" cone - or a 10" - or a 15" (it doesn't matter for this argument) ..... what we are hopeful of is that this puny little featherwirght driver can somehow 'take on' the entire pressure of the heavyweight atmosphere as it surrounds the speaker and pump it up and own (i.e. modulate it). No wonder this miracle is resitricted to the local environment around the speaker, in the room, in the house and not down the street otherwise you'd hear all your neighbours speakers: the noise would be unbearable.

    If you want to make a really worthwhile variation in sound pressure you need dynamite: you need to put a lot of energy into the source, so much so that if you put a regular borometer near the source you'd actually see it register the exposion. But - key point (at last: sorry) - to produce a big sound from our tiny little drive units (relative to atmospheric pressure) we're going to have to flog poor Driver to death dancing about on his toes whilst The Atmosphere just soaked up all the punches. To make any impact, Driver would have to have punches not of a few millimeters but by metres and metres like some giant steam piston. It's not going to happen is it!

    So, the limit of our loudness capability is cone excursion and that is reached long before the burn-out power handling ceiling. Were it not, it would be best to wear welder's goggles when listening to your speakers (and ear protection) in case the cones slapped you about the face. (Umm. Could be an interesting new concept ...)
    Alan A. Shaw
    Designer, owner
    Harbeth Audio UK

  10. #30
    Jasper Guest

    Default What is the material of jumpers and terminals?

    Quote Originally Posted by A.S.
    This thread specifically relates to the SuperHL5
    Dear Alan,

    I played SHL5 SSE since Nov 05. I use Marantz 7c+8b to drive it. The speakers provides me a lot of experience in matching with the amplifiers. They seems to be matched with old interconnectors and speaker cables, which are simple, thin, and natural without colouration.

    Two items along the electrical path which I am not so satisfied with, they are the jumpers and terminals of the speakers. They seems to be made from aluminium, not copper and is feeble and would be originated from China. I believe if they are made from copper, the bass would be more solid and deep.

    Before I use SHL5, I own HL compact 7. The jumpers and terminals are robust and is made from copper and originated from UK.

    If it is really what I guess, I will replace them with genuine UK made ones. So, Alan, please advise.

    Jasper

  11. #31
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    Default Re: Harbeth SuperHL5 -What is the material of jumpers and terminals

    Quote Originally Posted by Jasper
    ... the jumpers and terminals are robust and is made from copper and originated from UK. If it is really what I guess, I will replace them with genuine UK made ones. So, Alan, please advise.
    My good friend: I understand your question and your concern, but I do not want to take any money off you, and I do not want you to waste any of your money.

    First of all, the Harbeth biwire links are gold-plated brass. They are punched in the UK by hand one at a time, and then driven by car to a jeweller in London: he applies the gold plate. Then they are collected from him, he is paid (because gold is valuable and he demands to be paid immediately) and driven directly to our door. Then they are fitted to your speakers.

    But .... copper and brass is not mined in the UK any more. It is imported. From where? I do not know. Anywhere. Does the copper or brass know that it is from one country or another? No. Italian brass is as good as African brass.

    Please do not worry about the biwire links. The solution to that problem is very simple: a nice glass of wine - then the ghost of the link problem vanishes.
    Alan A. Shaw
    Designer, owner
    Harbeth Audio UK

  12. #32
    Jasper Guest

    Default Re: Harbeth SuperHL5 specific

    Dear Alan,

    Thanks for your immediate reply. How about the terminals? Are they made from brass and gold plated also?

    Actually I am quite satisfied with the performance of SHL5 SSE. It has high/low and most importantly has vocal full mid-range, quite a balance. I sit back every night on my sofa to enjoy my classical LP discs which had been stored for sometime.

    I have A/B test with the SHL5 in the sale agent's audio room before I bought SSE. I totally agree with you that it is a loss business for SSE (50 pounds for each pair).

    One very minor point is that the owner certificate was signed by your engineer, not you yourself. My compact HL speaker certificate is signed by you. I am precious of your certificates and I framed both of them and displayed them in my audio room.

    Next time when you are in Hong Kong, I must bring along the certificate for you to sign.

    Best regards.
    Jasper

  13. #33
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    Default Re: Harbeth SuperHL5 specific

    Quote Originally Posted by Jasper
    Next time when you are in Hong Kong, I must bring along the certificate for you to sign.Jasper
    I'd be delighted to meet you. I don't know about the terminals themselves. I guess that they are cast, but please don't worry about them. I guarantee that changing them will make no difference to the sound what so ever. Thinks about this: if we could squeeze even 1% of improvement out of any part of a Harbeth speaker by the simple expediency of changing a humble part (rather than me working late into the night so often on real engineering solutions) then believe me, I would have done so - long ago. But since there are no improvemnets to be gained "for free" I am obliged to struggle to make real improvements, no matter how exhausting the task.

    Incidentally, on a personal note, I read last week with great interest (and may I add, a sense of pride) the full page obituary of Sir Jack Cater, Hong Kong's former Chief Secretary who had a dramatic, positive and lasting effect in shaping the foundations that make Hong Kong the fabulous, open and exciting place it is. http://www.telegraph.co.uk/news/main.jhtml?xml=/news/2006/04/20/db2001.xml
    The world needs many more people of Cater and MacLehose's stature, but they are in very short supply it would seem.

    Our best wishes to all our friends in Hong Kong. (My affection towards HK is well known from my many visits).
    Alan A. Shaw
    Designer, owner
    Harbeth Audio UK

  14. #34
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    Default Re: Harbeth SuperHL5 specific - SuperGrille

    I just noticed (and felt) that the SHL5 SuperGrille, when in place, actually touches the aluminium tweeter.
    Does it matter if it is in contact or is there another protective cover over the tweeter (i.e. the SuperGrille is in fact in contact with the protective covering rather than the tweeter itself?
    Cheers

  15. #35
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    Default Re: Harbeth SuperHL5 specific - SuperGrille

    Quote Originally Posted by kuryakin72
    ... actually touches the aluminium tweeter. Does it matter ?
    The absolutely flattest frequency response is achieved when the gap between the tweeter's protective gauze and the underside of the cloth is at a minimum.

    Perhaps the way to think is like this: we are used to looking at the speaker from our hot seat in the room. Once, in Japan, I was told (and I absolutely agree with this)
    Alan san - you are thinking like a Westerner; from the outside in. Turn that around as we Orientals do: look from the inside out ...."
    I mean by this, imagine that you are the tweeter looking out into the room. Once you take this position you can see what a disaster the conventional wooden board with holds cut in it and covered with cloth is: diffraction from all around the aperture.

    The Harbeth SuperGrille solves all of these problems at a stroke but at a relatively high cost. First the metal for the frame has to be cut and bent exactly to length. Then welded by hand. Then fettled. Then degreased and sent away for powder coating (to prevent rust) .... then received by Harbeth and sent on to another supplier for cloth covering .... and finally back to Harbeth and fitted to your speakers. That adds up to about ten times the cost of a conventional board slapped onto the front. But technically/acoustically it's worth every penny.
    Alan A. Shaw
    Designer, owner
    Harbeth Audio UK

  16. #36
    danrubin Guest

    Default Re: Harbeth SuperHL5 specific

    I was just looking at the excellent photograph of the HL5's crossover that appears on the Harbeth website. That board is labelled "version 5, 16-02-2005". Since my HL5's probably pre-date that, I am wondering what changes there may have been between different versions of this crossover, and whether the change between versions 4 and 5, for example, is sonically significant.

  17. #37
    J.A. Boonstra Guest

    Default Re: Harbeth SuperHL5 specific

    Quote Originally Posted by AlanW
    I've had my Super HL5's for a couple of months now. It is unparralleled in my experience how they "get out of the way" and let the musical performances speak for themselves without intrusion. I am also continually amazed by their soundstaging and imaging performance, not to mention the realism of the orchestral instuments themselves on good classical recordings. The HL5's actually better my previous speakers (upgraded/modified KEF 101's) in the imaging and soundstaging department, and I had consistently found the KEFs to out-image all of the other speakers I had compared them to previously. I would not have thought this possible given the much larger size of the HL5 cabinet.

    Another major improvement over the KEFs is the image size and midrange purity. The KEFs, being a mini-monitor, tended to miniaturize the images, and it is thrilling now to hear bass strings as they sound with great seats at a live performance. Also, the string sound is the finest I've ever heard, as subtle variations in tone and phrasing are now laid bare. Obviously, the low-end performance of the Harbeths is another world entirely compared to the KEFs. Overall I couldn't be happier with the Harbeths, and consider them to be my best-ever audio purchase.
    I agree 100%. My previous speakers were Spendor BC1's, which served me well for more than 20 years. Thinking about that, I believe I had them almost 25 years. The BC1's are the same size and they also derive from the same heritage, which is the famous BBC monitor. However, hearing the Harbeth's was a revealing experience to me. The reproduction of details is stunning. For example: the difference in sound between a lute with "old style" gut strings and one with "modern" strings is far more obvious.

    For me it is very important that the Super HL 5's let me hear MUSIC, not loudspeakers. The sound is always musical, relaxed without being too laid-back, detailed without being overly analytical, creating a big musical "picture".

    I really love this concept. I have loved my Spendor BC1's for almost 25 years, but now the Harbeth Super HL5 shows me, that a big progress has been achieved without abandoning the concept of the Classic British Loudspeaker.
    It has taken me a long time to find a worthy successor for my BC1's and when I "found" the Super HL5's, it took me a few years to save enough money to buy them, but it was well worth the "investment".

  18. #38
    macolive Guest

    Default Re: Harbeth SuperHL5 specific

    Quote Originally Posted by J.A. Boonstra
    I agree 100%. My previous speakers were Spendor BC1's, which served me well for more than 20 years. Thinking about that, I believe I had them almost 25 years. The BC1's are the same size and they also derive from the same heritage, which is the famous BBC monitor. However, hearing the Harbeth's was a revealing experience to me. The reproduction of details is stunning. For example: the difference in sound between a lute with "old style" gut strings and one with "modern" strings is far more obvious.

    For me it is very important that the Super HL 5's let me hear MUSIC, not loudspeakers. The sound is always musical, relaxed without being too laid-back, detailed without being overly analytical, creating a big musical "picture".
    I wish I could concur with you on your observations...but I have to wait for my SHL 5's for a couple more days....They're finally coming!!!!

  19. #39
    J.A. Boonstra Guest

    Default Re: High Powered Amps with ..... anything

    Recently I had the opportunity to hear a pair of Harbeth Super HL5's being powered by an Audio Research VS 55i valve-amplifier (55 watts, push-pull 6550 valve configuration). I was very impressed by the sound quality. Later that week I heard an Ayon 300B SET amplifier, which sounded absolutely superb (but had very little power, something like 27 watts). Since then I have taken every opportunity to listen to valve-amplifiers (shop demonstrations, hifi-shows, etcetera).

    I confess, I am addicted to "valve sound". I want a valve-amplifier. Oh yes!
    Maybe next year or so, because I recently bought my Harbeth Super HL5. They cost me an arm and a leg, but it was very well worth it!

    My questions are:

    1) What kind of valve amplifier works best with the Super HL5's?
    I think, that SET's are underpowered, but they are too expensive for me anyway. So I guess it will have to be be a push-pull configuration (possibly EL 34's or KT88/6550).

    2) In hifi-magazines I often read, that one watt from a valve-amplifier is not he same as one watt form a solid-state amplifier. It seems, that one "valve-watt" can be compared with two or even three "transistor-watts". Is that true?

    3) Can you tell me, how to choose a valve-amplifier that works best with teh Super HL5's (other than just listening)?
    Is there a minimum power requirement?
    It seems, that valve-amplifiers react very sensibly to a speakers' changes in impedance behaviour. I read, that some speakers can get to almost 2 ohms, which can cause a shortcut the valve-amplifiers. How does the Super HL5 behave in this respect?

    I know, I am asking a lot, but I want to make sure that I don't harm my Super HL5's.

    J.A. Boonstra,
    Netherlands

  20. #40
    macolive Guest

    Default Re: High Powered Amps with ..... anything

    Quote Originally Posted by J.A. Boonstra
    Later that week I heard an Ayon 300B SET amplifier, which sounded absolutely superb (but had very little power, something like 27 watts)
    Hi,

    First of all, if the 300B amp that you heard was a SET than it could not have been 27 watts. I think the 300B SET amps are rated at about 8-10 watts.

    To answer some of your questions:
    1) What kind of valve amplifier works best with the Super HL5's?
    I think, that SET's are underpowered, but they are too expensive for me anyway. So I guess it will have to be be a push-pull configuration (possibly EL 34's or KT88/6550).
    1. I personally think that any valve amp can suit the SHL5 but other factors come into play. If you have a small room (say 3 x 3.6m) and listen to mostly small jazz ensembles or vocals than a 300B set amp will probably do well. A push pull amp will give you power but lacks the immediacy and finesse that SET amps can provide.

    I've had a KT88 based amp at 200watts per channel and I had a 2a3 SET amp. I preferred the 2a3 but it lacked power for orchestral music. I switched to an 805 SET (50 watts per channel) and was generally happy. In the end, I wanted the best of both worlds and I bought a BAT VK-75. This is a single ended bridged design using the 6c33 triodes. Needless to say that I am happy but there is an itch to try a 300B amp.
    2) In hifi-magazines I often read, that one watt from a valve-amplifier is not he same as one watt form a solid-state amplifier. It seems, that one "valve-watt" can be compared with two or even three "transistor-watts". Is that true?
    2. I've heard the same about tube watts but I've never heard anymore than that.

    3) Can you tell me, how to choose a valve-amplifier that works best with teh Super HL5's (other than just listening)?
    Is there a minimum power requirement?
    It seems, that valve-amplifiers react very sensibly to a speakers' changes in impedance behaviour. I read, that some speakers can get to almost 2 ohms, which can cause a shortcut the valve-amplifiers. How does the Super HL5 behave in this respect?
    3. There's really no way to choose an amp but to listen. The impedance curves are on the website and it is a fairly easy load for valves. Valves don't like impedance dips.

    BTW, I just got my SHL5's last night...they look and sound great! Thanks alan! Specially for the autograph.

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