View Full Version : How little power do I need for my Harbeths?
Those of you familair with my opinions about excessive and unnecessarily powerful amplifiers to drive their Harbeths may take comfort in this story .....
When I was in southern China recently at a hi-fi show, I personally listened to a pair of SHL5s driven by two monoblock 300B tube amps - each about the size of a house brick. The power rating of each amp was about 7W. The sound? Excellent - and loud enough to fill the room.
It is true of course that the amp would be operating at its limit, but being a tube amp this soft clipping was not audible.
From this I think we can say that just about any amp even in the low tens of watts rating should make an excellent match to Harbeth speakers, which are designed by me to have as easy and universally suitable electrical load as possible. In short, don't even consider changing your amp from whatever you currently have until you are absolutely sure that such an upgrade really would give you more performance. The name of the game is surely to win the most performance for the least financial outlay, and in that respect a pair of Harbeths will always pay handsom dividends.
airdavid
10-09-2006, 10:45 AM
Those of you familir with my opinions about excessive and unnecessarily powerful amplifiers to drive their Harbeths may take comfort in this story .....
When I was in southern China recently at a hi-fi show, I personally listened to a pair of SHL5s driven by two monoblock 300B tube amps - each about the size of a house brick. The power rating of each amp was about 7W. The sound? Excellent - and loud enough to fill the room.
It is true of course that the amp would be operating at its limit, but being a tube amp this soft clipping was not audible.
From this I think we can say that just about any amp even in the low tens of watts rating should make an excellent match to Harbeth speakers, which are designed by me to have as easy and universally suitable electrical load as possible. In short, don't even consider changing your amp from whatever you currently have until you are absolutely sure that such an upgrade really would give you more performance. The name of the game is surely to win the most performance for the least financial outlay, and in that respect a pair of Harbeths will always pay handsom dividends.
Alan,
what about the punch and bass power? Is it necessary a powerful amp to have them? I listende to Compact 7-es with 50 watt naim nait 5i and with Nac 202-200 with 70 watt, same room: a more powerful bass and punch with 202-200, even if it was loud enough with nait 5i too....
Bye,
David
...
what about the punch and bass power? Is it necessary a powerful amp to have them?Yes, I think one advantage of a more powerful amplifier is, as you say, in the bass range.
I was not saying that a tiny amplifier is all you need! I was making the point that even with just a few Watts it's amazing how good a Harbeth can sound especially on music with a well balanced sonic spectrum.
tobes
11-09-2006, 01:19 AM
I've never used one of the flea powered SETs that Alan is talking about, but I personally wouldn't want to be without the scale/dynamics and low frequency heft that is acheivable with my 175Wpc amp.
The C7s sound very nice with average (but not sloppy!) system setup.......however they sound flat out amazing when you apply the meticulous care they deserve.
I love these speakers!
airdavid
11-09-2006, 10:25 AM
Yes, I think one advantage of a more powerful amplifier is, as you say, in the bass range.
I was not saying that a tiny amplifier is all you need! I was making the point that even with just a few Watts it's amazing how good a Harbeth can sound especially on music with a well balanced sonic spectrum.
Thank you,
so do you think a 50watt with 250 va amp is enough for Harbeth Monitor 30 in 20\25 squaremetres room ?
Regards,
David
p.s.
"The istant Email notification" doesn't work !!!!
Paris Kotsis
11-09-2006, 10:58 AM
Alan,
did you hear super resolution with this amp or just "good resolution"? Me, trying to drive M30 with 5 Watts of a 2A3 based tube amp, I got some very natural tonal colors but not much detail.
Paris
Paris Kotsis
11-09-2006, 11:12 AM
David,
I find the 50 Watts of Crimson 620E absolutely fine with M30 in my listening room, which is about the size of yours. They can play very loud with control and also very clear at ultra low levels.
Paris
airdavid
12-09-2006, 09:27 PM
"The istant Email notification" doesn't work !!!!
Anyway,
does anybody listen to Monitor 30 with Exposure XXXV ?
In Italy it's said it's a wonderful match...
David
ddort
08-05-2007, 07:20 PM
Very little, at least if you share my sensibilities...
I have a Fi X 2A3 amplifier, using JJ Electronics 2A3-40 tubes, and a Pathos Classic amp as well.
When I got my Model 30s, I moved the Fi amp to the library, paired with some efficient Triangle speakers, in the belief that I needed the extra power from the Pathos Classic.
I found myself in the library a lot, because I missed that SET magic, even though I loved the Model 30s.
About two weeks ago, I paired the 2A3 with the Model 30s.
WOW.
I don't know what kind of music you guys listen to, or at what volume... But the Lindsays (and guest) playing the Schubert Quintet at midnight will make a stone weep.
Don't let them tell you you're missing something..... Love what you've got, and three watts are fine.
Ned Mast
27-10-2007, 02:07 PM
Alan,
I enjoyed reading this article in the Nov issue Hi-Fi News. The photo of you holding the 12in Radial driver for the M40 puzzled me a bit, though. . . Elsewhere in the issue another question was raised by Keith Howard in his final installment of his four-part series on amplifier power, and I wonder what your thougths are. Using a Musical Fidelity kW750 power amp and B&W 805S speakers, he basically concluded that much music demands far more peak power than we generally think it does. During parts of the music he played - at high but not excessive volumes - even his 750W amp clipped a bit.
I have read other statements by audiophiles who have measured amplifier output to be over 400 watts during passages of classical music, so know that Keith Howard is not alone in his views. But more often, I read that 100-150 watts is adequate for most "reasonably" effeicient speakers. Of course, slight clipping might be benign and inaudible, but perhaps those of us who listen to orchestral and orchestral/choral music should think in terms of more watts to drive our Harbeths? After all, watts are cheap, unless one insists upon exotic electronics.
Ned
... he basically concluded that much music demands far more peak power than we generally think it does. During parts of the music he played - at high but not excessive volumes - even his 750W amp clipped a bit ... but more often, I read that 100-150 watts is adequate for most "reasonably" efficient speakers. Hello Ned,
Machismo is alive and well it seems! I am sure that Mr. Howard's observations are valid but are not IMHO relevant to the reproduction of music at home in a socially responsible way. I have actually answered this particular question here before but I agree that it is one of those issues that will never lie down.
Have a look at this item here (http://www.harbeth.co.uk/usergroup/showthread.php?p=886#post886) which I hope brings together various previous comments.
I stress:
- you DO NOT need a big amplifier to make beautiful music at home!
- you MUST take care of your ears!
- you must be socially responsible! Your neighbours are not interested in your music. They have a right to silence and privacy! Likewise, the drama programme being recorded in this studio does not want (or need) to hear the football commentary being edited in the adjacent studio!
And so, Harbeth speakers are unique in being designed to sound natural and full bodied at a normal, reasonable listening level. This is entirely because of their BBC heritage - they were/are used in BBC control rooms which are about the same size as our listening rooms and the speakers are quite close to the listener - so they DON'T NEED to play them loud for them to sound natural!
Ned Mast
27-10-2007, 07:56 PM
Thank you for your response, Alan. Sorry to bring up an issue that - as you point out - has been dealt with rather extensively here before. I think I can see merit in both sides of this issue; lots of power is fine, or perhaps much less is sufficient. Of course lots of power need not imply excessive volume. I suppose as one listens in one's own environment, he/she will arrive at what seems adequate for that space. But if one finds the music not pleasant sounding at fairly high volumes, I also wonder if it might be because the amp is being over-driven. How many of us will have heard this event enough to recognize it? We might just assume the recording is not that good, when in fact it might sound fine at that volume with adequate power and without the clipping. I include myself in this group, by the way.
Ned
David Schalkwyk
27-10-2007, 10:22 PM
Alan,
I enjoyed reading this article in the Nov issue Hi-Fi News. The photo of you holding the 12in Radial driver for the M40 puzzled me a bit, though. . . Elsewhere in the issue another question was raised by Keith Howard in his final installment of his four-part series on amplifier power, and I wonder what your thougths are. Using a Musical Fidelity kW750 power amp and B&W 805S speakers, he basically concluded that much music demands far more peak power than we generally think it does. During parts of the music he played - at high but not excessive volumes - even his 750W amp clipped a bit.
I have read other statements by audiophiles who have measured amplifier output to be over 400 watts during passages of classical music, so know that Keith Howard is not alone in his views. But more often, I read that 100-150 watts is adequate for most "reasonably" effeicient speakers. Of course, slight clipping might be benign and inaudible, but perhaps those of us who listen to orchestral and orchestral/choral music should think in terms of more watts to drive our Harbeths? After all, watts are cheap, unless one insists upon exotic electronics.
Ned
I asked the same question some weeks ago after reading the same article. All I can say in addition to Alan's assurances is that my 1960s 17 (or so) Watt Class-A Sugden drives my HP-3s to perfection. I've tried a 200 Watt MOSFET amp that was slightly more dynamic but not as musical. I prefer the latter.
David
It's an important issue and it needs to be regularly re-explored so make no apology for raising it again. I take a very pragmatic view on all this power stuff, namely that regardless of how much power you have to ram into the speaker's terminals, think for a moment about what's going on inside the speaker cabinet.
Rough numbers: electrical to acoustic conversion efficiency (i.e. electricity >>> sound waves) is 1%. That means that if you have a 100W amp, 99 Watts are being burned up as heat in the speaker for which we have no sonic benefit. If you have a 750W amp, 742W are being radiated as heat in the speaker, assuming, in both cases that the amp is working flat out. Now how would you like to handle a 99W light bulb? Or a 742W electric bar heater? You'd be mad to try and you'd severely burn yourself. And the plastic cone of the speaker is of similar organic make-up to your fingers and it too can burn - or rather melt.
At the final analysis, almost all of that 99% power that is wasted as heat, not as sound and ends up in the voice coil. As you can see perhaps from the attached, the wire is extremely thin and obviously can not take more power than it can radiate - in the confined and unventilated environment of a speaker cabinet. So, if the voice coil can't radiate the heat, why force the power into the poor speaker? It makes no sense to me at all.
Compare and contrast (as they say) the thin hair-like wire of a voice coil with the fat wire used in an electric heater and you'll see why heaters last for years even dissipiating all their power as heat!
Ned Mast
28-10-2007, 03:04 AM
Thank you again, Alan, for your forebearance in discussing this issue of amplifier power. I see no reason to take issue with what you have said, and will only ask a question or two in this - my last post on the subject.
Firstly, if I am running 50 watts or 500 watts into a speaker, and listening at peaks of approximately 87 to 90 dBs, am I not essentially putting the same amount of power into the speakers with both amps? (I do want to emphasize that I would only want enough power to listen at these kinds of peak dB levels - to my ears not excessive - without distortion.) Of course, when listening to classical music these kinds of peaks are only occasional - not at all constant. Quite different from rock music, for example.
Secondly, if only 1 % of the power of an amplifier is used in the production of music, wouldn't one want to err on the side of having adequate power rather than too little? Again, emphasizing that the power would not be used for achieving higher volume levels, but simply to be sure that those peak moments would be un-distorted? I hope you will understand that I am in no way trying to be argumentative about this; I simply would like to understand why power is an issue at all. Or, to what extent it reasonably should be. I will also freely admit that I have listened to my M40s with three different amplifiers, with ratings of 60w, 275w, and 300w into 8 ohms and have noticed no obvious deficiencies in any of the three. So perhaps I have truly answered my own questions, though the comparisons were not long term enough to be definitive.
I would not have brought this whole issue up were it not for the fact that I am considering (quite speculatively) moving to a digital amplifier, since I am using a digital pre-amp and there may (or may not?) be advantages to being digital all the way to the speaker; ie., no loss of resolution at lower volume levels. I would not be getting a digital amp with nearly the power of my analogue amp. I am assuming that watts are watts, be they produced in the digital or analogue realm.
With gratitude for your patience and understanding, Ned
There are a few observations about the 'power issue' which worry me:
1. Why have the power available if you can't use it constructively? (Why drive a gas guzzling 4x4 on choked city streets just to make the point that you have power?) If you have it, there is an irresistible temptation to use it - perhaps unwittingly.
2. The speaker draws power from the amplifier and the amp delivers that power to the speaker on demand. The power drawn depends somewhat on the resistance of the speaker, the listening level and the type of music all in combination.
You start listening. You enjoy. You increase the volume. 99% of the extra power drawn by the speaker is wasted as heat in the voice coil*. The voice coil quickly heats up. Its resistance increases which opposes the volume increase. So you turn it up a bit more. The voice coil becomes even hotter. It's resistance increases more. Now its temperature is up in the 150?C+ region. You still want louder and your amp can deliver still more power - so you turn it up. Now the voice coil temperature is over 200?C close to the melting point of the cone. Sooner or later either the voice coils fragile wire will overheat and fracture (as light bulbs eventually do) or the cone/voice coil junction will melt. Either way, you'll need a new expensive drive unit.
*Actually a little heat is generated in the crossover.
3. A Harbeth is by definition smooth sounding. It is soooo tempting to turn up the volume!
4. As you increase replay level your ears operate their wonderful Automatic Gain Control mechanism which works through tiny muscles which slowly fatigue. Mix that with a little (or a lot) of alcohol and result: you turn up the amp to 'override' your own internal volume regulator.
5. Human nature ......... ! You may be able to exert maximum self control with your 750W amp but what happens when the kids are home alone!
6. Harbeth's are designed to sound full bodied and natural at moderate listening levels. When played far above that target level they are not optimised.
7. Take a look at the attached pictures of the historical influence on Harbeth designs, right back to the 1940s. All but one are BBC studios in which you will see that the sound engineer is remarkably close to the (big) speakers. The replay volume level is low and the monitor speakers would have sounded full and natural. Contrast that with, say, the wonderful Capital recording studio with the speakers far away in the wall. That's a wholly different monitoring situation where 750W may well be necessary, and tolerated by speakers and listeners. Of these two environments, the BBC-type relative-nearfield setup is much more akin to how we use our Harbeths in our homes and the minimal power we need to sound natural.
>
Ned Mast
28-10-2007, 05:17 PM
I agree wholeheartedly with the first part of your number 1 item in your last post, Alan; I abhor the trend in this country to drive humongous SUV's which are uneconomical, don't ride well or handle well, and are a menace to both other cars and their own drivers. The second part - concerning the irrisistable urge to use amplifier power - may apply to many listeners, but I honestly don't feel personaly is applicable.
From my listening experience, it seems that most CDs have an ideal listening level. Too low, and the soft passages become inaudible; too loud, and the loud passages are overbearing. For most CDs, I find that I can leave the volume level in approximately the same position. Small adjustments are sufficient; never a continual raising to enjoy the music more, since that leads to quite the opposite result! All of your other points make absolute sense.
Thank your for posting the photos of the monitor control rooms. I am a bit curious about the positioning of the M40s. In some of the photos it seems that they are quite close to the walls behind them. I can't tell if there is acoustic treatment behind them or not. In my room, getting them within 3 feet of the wall behind them gives a substantial boost to the 50Hz region, and not quite as large a boost to the 100 to 110 Hz region. These are the two primary peak regions. Fortunately, DSP takes care of this quite nicely.
By the way, in response to a comment from an earlier post of yours concerning the expense of DSP. I agree that it might be considered expensive, but - to me - in a relative sense, not unreasonably. Many hi-end electronics and cables sell for far more than DSP units, and effect the sound far less. And to deal with that bass energy with commercial room treatment products would, I believe, not be inexpensive. And then what would the room look like? In addition to which DSP will effect the entire frequency range - not just the bass - though not as dramatically. I add this because I believe that controlling room reflections and modes is not treated as seriously as it should be by most listeners. I feel that I am hearing the true, uncolored sound of the M40s in a way that I never did before DSP.
Respectfully, Ned
I agree wholeheartedly with the first part of your number 1 item in your last post, Alan; I abhor the trend in this country to drive humongous SUV's which are uneconomical, don't ride well or handle well, and are a menace to both other cars and their own drivers...
Thank your for posting the photos of the monitor control rooms. I am a bit curious about the positioning of the M40s. In some of the photos it seems that they are quite close to the walls behind them. I can't tell if there is acoustic treatment behind them or not. In my room, getting them within 3 feet of the wall behind them gives a substantial boost to the 50Hz region, and not quite as large a boost to the 100 to 110 Hz region. These are the two primary peak regions. Fortunately, DSP takes care of this quite nicely.Concerning SUV's they are also exceedingly dangerous to pedestrians as they have moved the centre of impact upwards from the leg region (bad enough) to the head region (especially in children) and chest region where medics say the damage is far more severe than at the legs.
Anyway - room treatment in M40: yes, the old-school BBC studios, that is, those built up until the last year or two when the new guard took to the purse - were all what are referred to in the BBC (with a faraway look) as 'proper' studios with 'proper' reverb times and 'proper' absorption. I'll see if I can find the BBC papers that describe their construction. The basic rules of good acoustic space were certainly documented and well understood at the BBC in 1930, but of course, discarded now in favour of the trendy 'all glass' construction.
There has never been a case of an M40 installation (almost every one I've personally delivered and set up, even to Scotland and Ireland) where any comment has been made at all about the bass. All I've needed to do - depending upon the studio's HF characteristics is to lift (never cut) the HF when room lagging is really heavy. And that's it. But we know that when the same M40 is installed in *some* tricky domestic listening spaces there will be a bass excess. You've solved the issue with DSP - a very elegant way of doing so - and in the case of the M40.1 the whole bass driver/room interaction has been reconsidered in favour of a shallow roll-off which is augmented by the room to give an extended bass. It remains to be seen if that will drop into a BBC environment: I suspect that the pro-users will need some bass boost!
As for CD listening volume level: Peter Walker of QUAD put it so aptly: 'the volume control is like a cameras zoom function. Too loud and the performers are pulled right into your face; too quiet and they recede into the distance. For every picture and performance there is an optimum zoom, an optimum volume level to capture the whole canvass'.
holden
11-01-2008, 05:29 PM
I'm not sure i'd call myself an audiophile, i only have mid priced stuff. I use a Leben 12-watt vacuum tube amp (cs-300), and an Arcam cd-33t with my Harbeth compact 7-es2's. I sit close - about 1 and a half metres away. I can't turn the amp up past 11 o clock, or the police will visit (This is Japan!) . Anyway, It sounds superb. I previously had an older (Quad), more powerful amp, but it sounds feeble in comparison. I imagine this power would be quite sufficient in any small/mid sized room, though i guess things might start to deteriorate at a certain point in a largish room. I can't imagine why much more power would be needed in a relatively small space. The whole set up sounds very convincing and bold to me. I've got repetitive strain injury in my feet from too much tapping.
DSRANCE
11-01-2008, 06:32 PM
I'm not sure what it is about valve/tube amps - maybe it's the extra ringing and distortion (grin)... - but many of them seem to do with just one or two watts what solid state amps do with ten times that amount. Probably not the place to discuss it though :)
I'm certainly a victim of the need for more volume. First thing in the morning I can listen quietly without too much bother, but as the day goes on (even in enforced retirement) my Tinitus gets worse and I need to turn it up (I used to make the excuse that the system warmed up but now I'm not so sure after the first hour or so). Fortunately for my ears (what's left of them), I can't play music very loud now and "herself" dislikes my tastes anyway, so the volume stays down.
I wonder if there will ever be an ACTIVE Studio 30/Compact 7? I suspect doing the crossover electronically before the amps would be the icing on their cake... well, I can dream...)
I am very encouraged to learn that a 23 watt DNM amplifier was able to drive the new 40.1 speakers...my question is whether or not one of these models (the 40.1 or Super HL5) would be easier to drive and a better match for my amplifiers? Or, is there another model in the line that I haven't consideredGood question. This amplifier/watt issue seems to come up time and time again and clearly there is a huge amount of misunderstanding about this. We've covered this here many times before, but let's have another look at it. It really is incredibly simple. Let's be absolutely clear about watts. A watt is a watt is a watt. A heat watt describes the same available energy as an electrical watt, as a steam watt and as a sound watt. A watt is a unit of power. This unit of power can not be faked or gerrymandered in any way*. Our entire physics depends upon the constancy of our units of measurement and their cross-conversions.
Now let's compare 23W of conventional filament electric light bulb with 23W of power to drive a speaker with its heavy cones. The power output from one single conventional 23W light bulb would barely fill the room with sufficient light to read by; all the bulb has to do is to send out weighless photons which requires no effort from the bulb at all.
But now let's flood the room not with light but with sound ...let's draw the same 23W of power from the National Grid and feed it to a speaker via a power amplifier. This time, the 23W of power is going to have to (try) and do some serious work, moving 50g or more of cones in and out according to the music, accelerating them from standstill and stopping them dead. And remember, loudspeakers have a typical efficiency of about 1% in conversion process from electricity in to sound output - yes, you read that correctly: one percent efficiency: 99% of the power a speaker draws from the amp is wasted as useless heat and never becomes sound.**
I think that you can see that 23W really is a very small amount of power to move heavy cones when 99% of it is wasted as heat. 23W obviously will perform useful work and it may sound great if you listen close to the speakers, you play music at a low level and the music has a relatively low dynamic content - say, solo classical guitar, string quartet, spoken voice etc. etc.. Personally, I'd be happier if you matched your 23W with a higher-efficiency speaker such as the SHL5 or C7 where you will will be able to play louder and have a (little) power in reserve.
* Think of how much power it takes to boil a kettle to 100 degrees C. There is no argument about this. It takes x watts. No more, no less. If you have less than that required amount of power available to you, you cannot boil the water. You may like lukewarm coffee but you will never burn your tongue on lukewarm water - to do that you need to put more energy into the water, to make it really boil. It's the same with sound: you may like 'lukewarm' music, but if you want to make your music 'boil' you have to put more power into it. It's that simple.
** Apparently, a full orchestra playing at maximum power generates about 70W of acoustic power. If we say that a speaker operates at about 1% efficiency (very typical for all hi-fi speakers) we would need, in theory, 7000W of amplifier (7kW) to attempt to recreate the same loudness as an orchestra in our listening room. The speakers would burn-out in under one second, and we would cause structural damage to the building and a huge irritation to neighbours. So, in fact, we are accustomed to 'recreating' live music at a tiny fraction of the peak sound level we would hear at the recording itself. If you think about it, we must be listening at about 1% of the real-life peak level. This is the reason that we are satisfied with the sound quantity generated by extremely small amplifiers. For me, the issue is that if I like the music, perhaps I'd like to turn up the volume a bit and listen at 2% or 5% of the real volume - I'll need some real watts to do that. No amount of kiddology with amplifier specs. is going to give me more loudness .... for that I'll need more watts.
David Vair
10-03-2008, 05:07 AM
Thank you very much for your thoughts and explanation. In light of the power need for the new 40.1, why did you choose to mate it with the 23 watt DNM amplifier at CES rather than something with more power reserves? Is the Super HL5 that much more efficient than the 40.1?
I am very interested in your speakers, very, very few manufacturers emphasize the need for fidelity to natural tonality and timbre; but if you don't have these, then instruments stop sounding like themselves and begin to sound more the same.
I am not personally responsible for the selection of any electronics that is partnered with our speakers. Our policy has always been that I design Harbeths to be a easy 'amp friendly load' and that is as far as I need to go. Whatever others choose to marry with the speakers will then certainly work and give pleasure. As with all such speaker-amp-CD combinations, there are well established personal preferences and it is not my role to examine or explore those issues. I think we were trying to make a statement along the lines 'you may be surprised just how loud and sweet 23W can sound even with big speakers' and that we certainly achieved! In short, I have enough to keep me busy on the speaker front without straying into the electronics arena!
The SHL5 is a little more efficient. You may just detect it on an A/B switchover.
Is that really the case that few manufacturers care about tonality? Since I don't mix with the hi-fi crowd socially or otherwise, I really don't know.
chord
10-03-2008, 03:25 PM
It is still puzzling to me how speakers can unload 99% of wasteful heat energy so effectively. After some period of listening, the speakers should be warm to touch. However, it seems not the case in real time situation.
Moreover, would the drivers (mid or bass cone) perform differently at different temperatures? If so, has that been taken into account in the process of design?
Specificaly to Harbeth speakers, what is the optimal range of temperature (ambient temperature) for the speakers performing as the design intends?
Would the speakers require some kind of "warm-up" in cold weathers for example?
You can find a fuller description of the efficiency issue here in Wikipedi (http://en.wikipedia.org/wiki/Loudspeaker) (scroll down to Efficiency vs.sensitivity). Yes, the room temperature is important and we've already covered that here (http://www.harbeth.co.uk/usergroup/showthread.php?p=1070&highlight=temperature#post1070), and yes, it is very much taken into account by me. Yes, speakers will sound quite different when they are significantly colder than comfortable room temperature.
99% of drive unit failures are caused by burn-out of the voice coil. The listener wants more loudness and pours more power into the speaker voice coil. As only about 1% of that power is converted to sound, 99% heats the voice coil, and beyond a certain power/time point, this process runs away and the voice coil cooks. Ultimate breakdown occurs when there is insufficient ventilation to cool the voice coil (and cone) as it excurses back and forwards.
Attached is a picture of a drive unit showing the aluminium voice coil tube (or former) that has become so hot that it has melted its way through the speaker cone. Obviously, this took many minutes and a lot of watts: the owner was distracted by a long phone call and by the time he returned to his listening room the damage had been done. The attentive listener can always hear that a drive unit -especially a small one - is being strained as power input equates to a dramatic cone motion in a small driver - an attendant increase in tell-tale audible distortion.
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bbtan
30-07-2008, 01:27 AM
My Compact 7 is driven by Simple 4 SET amp of 11 watts....and I can say it's beautiful...most natural and heart warming......and I don't like loud music..only naturally wonderful music..
NikPer
16-09-2008, 09:29 AM
I am using an amplifier with 2xEL34 per channel in Triode mode with my SHL5 and i am very happy with the sound.
hifi2me
18-09-2008, 09:19 AM
Anyone who has experience with Lavardin IS or IT version?
coredump
18-09-2008, 01:17 PM
Anyone who has experience with Lavardin IS or IT version?
Well, I'm using the IS to partner my SHL5. Are u worry abt the 30Watts of output power? Not to worry, it can drive it effortlessly. with a normal CDP output of 2V, at 9 o'clock, the volume is enough to fill up my room of 3m by 3m. Good for all genre. :)
Rabbit
19-09-2008, 07:35 AM
I'm really enjoying the C7ES3's I have at home right now (loaners until my brand-new set arrive); I suspect that this model of speaker will be with me for a long time. In fact, I remind myself that, as Alan says, they're a "capital equipment" purchase, so I'm actually thinking that I'll be bequeathing them to someone in my family when I expire. They also sound absolutely fab with my Naim electronics; a very complementary system, IMO. Involving, yet easy on the ears.
But that's not why I'm posting - I'm just curious, where does the C7ES3 rank in terms of efficiency in the Harbeth lineup?
Regards,
Rabbit
Rabbit
19-09-2008, 07:52 AM
I'm not sure i'd call myself an audiophile, i only have mid priced stuff. I use a Leben 12-watt vacuum tube amp (cs-300), and an Arcam cd-33t with my Harbeth compact 7-es2's. I sit close - about 1 and a half metres away. I can't turn the amp up past 11 o clock, or the police will visit (This is Japan!) . Anyway, It sounds superb. I previously had an older (Quad), more powerful amp, but it sounds feeble in comparison. I imagine this power would be quite sufficient in any small/mid sized room, though i guess things might start to deteriorate at a certain point in a largish room. I can't imagine why much more power would be needed in a relatively small space. The whole set up sounds very convincing and bold to me. I've got repetitive strain injury in my feet from too much tapping.
If you care about the sound of music playback, you're an audiophile. At least, I considered myself such when all I could afford was a second-hand Sansui receiver, Kenwood 'table and "smaller" Advent speakers. Spending loads of cash doesn't mean anything. Besides, Arcam is well-respected kit and Leben tube kit VERY admired in "audiophile" circles!