Harbeth older and discontinued models:

[MarkNC]

Hi all-originally wasn't going to jump into this, but I must say as an SHL5 owner that I don't believe the supertweeter in this system is at all useless. The small diameter offers greater dispersion at the highest frequencies; even though, as Mr. Shaw has pointed out, there's not a lot of content up there, there are some not-unimportant upper harmonics even with acoustic music.

And considering the delicate quality of what I hear with instruments such as bells, cymbals, glockenspiels, etc. (better than with any speaker system I've had) this seems to be a worthwhile design option.

[RogerMBond]

I think the Monitor 30 is the best speaker I've ever heard regardless of price. That means, Mr. Shaw, that you as a designer have come closer to the mark of perfection than any other speaker designer in the history of hi-fi

My ears tell me that Mr. Shaw, more than any speaker designer I'm aware of, get's it. Anyone with ears is very likely to get what "it" is with just a short audition of any Harbeth product. Sir, of you don't get it, I'm sure there is a competitive model somewhere for you.

??? No, thank you.

[RogerMBond]

Really? I'm surprised you have the time to do anything else.

Also, to repeat a straightforward question you've chosen to ignore: have you actually heard the SHL5 and Monitor 40.1 yourself?

I don't have time to do very much else. Since 1997 I've been evaluating, collecting, and dealing exotic modern and vintage hi-fi, visiting manufacturers, various listening rooms, writing reviews, and going to shows. Yeah, I've heard a lot of speaker systems....including the SHL5 and Monitor 40. Believe it or not, it was actually a Naim/SHL5 combo that interested in me in Harbeth in the first place...even though I wasn't a fan of the tweeter(s) right out of the gate. Ironic, eh?

[RogerMBond]

Ummm. Interesting.

The core of this is that based on inadequate market research (of one individual's preferences) I am being told that I should invest precious time developing - as it were - a hybrid model between the M30 and the SHL5. That's like introducing a car model between that BMW 3 series and 5 series; let's call it the BMW 4 series. Business sense tells me that the likely consequence of this '4 series' is not that it increases overall sales of BMW much if at all, but that it will now confuses the would-be 3 series customer and the would-be 5 series customer. In short, it would be a marketing distraction. Marketing people have an axiom: "the confused customer never buys" and setting aside all issues of technical merit, just because it could be designed does not mean it should be designed and definitely does not mean that it will sell.

And yes, it is all about money. I do not design speakers to tickle my own fancy. Harbeth is a successful business and there is no place in our business for designing and introducing products to give me kick and our sales channels a headache. Sales, design and manufacture are integrated interdependent activities.

I'm struck by the contradictions in what we've read, which seem to praise the RADIAL driver (thank you for that) yet are dismissive of any tweeters other than the treasured SEAS units in the writer's possession. A donor vehicle is being sought to transplant these tweeters into but at first it can be a thin-wall Mk2 cabinet with a polypropylene driver (read about Harwood's PP here in Newsletter 27) and but then it cannot be the virtually identical thin-wall SHL5 but it could be similar BBC-inspired legacy thin-wall '2 cubic foot' cabinets. Strange.

What I suspect is not fully appreciated here is that the relatively minor importance of the tweeter, regardless of whether it is made from knicker-silk (a soft dome), a pressed metal sheet (hard dome incl. aluminium) or any other crude or exotic material you care to mention, in a hifi speaker. That's because there is almost no energy in music above about 5kHz. We know this because even on AM radio we can follow-along with classical music, pop and speech, and the AM sound is similar to that of disconnecting the tweeters, or conveniently, unlinking one bi-wire link. So it is better, in my opinion, to focus design time and effort on optimising the woofer/cabinet/grille/basic crossover where 90% of the audio energy is needed and then, not exactly as an afterthought but as a second pass perhaps, make a selection of tweeter 3-6 months down the design path. That keeps all the options open, and avoids the designer working himself into a technical corner because of poor early-on choices. An open-mind is definitely beneficial, and less stressful.

We have been down this hybrid route once before. I am reminded of the Harbeth HL-K6 speaker (remember it?) which one distributor insisted was desperately needed back in the mid 90s. It used the RADIAL woofer from the C7 and the tweeter from the P3 in a box which was only just wide enough to shuffle the woofer into from the rear. Result: as I explained above. P3 customers found it too big and C7 customers too small. It was a distraction.

On the subject of the tweeters uses in the old-style BBC monitors, I must say that having recently given a quick listen to the Celestion/Coles HF1300/1400 on one of those old 70s monitors I was surprised just how good it was. It shouldn't have worked considering it's origins as a full-range intercom in a WW2 battle-tank (yes, truly!) but it did. But there again, using underwear-silk impregnated with flexible resin to form a piston is hardly an engineering solution to tweeter diaphragm design is it! It shouldn't work, but it does. But is it necessarily better than a hard dome tweeter? Common sense tells you that it can't be. Each tweeter design has a different set of properties and it is a little foolish to dismiss 'all hard domes' or 'all soft domes'.

You wouldn't say all straight-6 engines were certainly superior to all V6 ones (or vice versa) would you?

Mr. Shaw....an excellent, informative post, as usual. Thank you. I'd only like to add clarification to what seems to be confusion about my thought process regarding the modification of an older HL monitor. First, let me say that the ringing cabinet isn't a deal breaker for me. It actually doesn't bother me very much at all. I only noted that it was there. The tweeter section is what I find objectionable. So in other words, I could happily live with the SHL5 were I to swap tweeters and disconnect the supertweeter. But why would I want to invest real money in something that I was only going to carve up? I would not. That's where the old HL monitor came into the picture. When finished with the MK II update/mod, would I have something as good as a contemporary AS design with the Radial driver? Absolutely not. But I'll bet it would sound damn satisfying and I'd be into a few hundred dollars vs a few thousand. In other words, I am willing to accept 70% of what I really want for 10% of the cash output. When you enlightened me about the possible failure of the old, poly cone...that inspired me to stop thinking about the MK II and instead focus on obtaining a pair of Monitor 30's.

[Miles MG]

I have a pair of early (Serial Numbers: 228 A & B ) HL Monitors. The clear polypropylene units have white roll surrounds, which show no signs of distress. The Audax tweeters are OK, too. Falcon Acoustics can supply new Audax dome/voice coils. I had a pair fitted to my original Spendor SA1s. I also have the original 'Harbeth Acoustics Type HL' Instruction/Spec. sheet. Apart from quotes from users of the speakers, there is a profile of H D

Harwood and comprehensive notes on the design. In the HL Monitor Specification it clearly states the crossover frequency as 2 Khz. By the way, the price quoted was £298 + VAT. I love my HLs. I wouldn't change them for anything else... MGM .

{Moderator's comment: as Alan explicitly stated here recently, the crossover frequency of the Mk2 he measured is NOT 2kHz. Whether that was a misprint or design revision we will never know. One issue to be aware of is the correct phase of the tweeter if you attempt DIY repairs. You *need to make sound measurements of the frequency response of the complete speaker* after repair because there is NO standardisation on Audax tweeter terminal colours/markings, replacement tweeter parts or any other alternative tweeters. You have a 50/50 chance of connecting out of phase.}

[DSRANCE]

Old news I'm sure and I don't have documented evidence apart from memories, but I think the earliest original HL's went through a tweak or two on its way to settling into production. Within a very short time, we (at KJ) were firm fans of the model and yes Martyn, they did seem to build on the dearly beloved BC1, which was starting to sound just a bit thuddy/tubby, constricted and tired in comparison I recall back then, the bass just not being competitive as the competition improved. The HL just let the music flow effortlessly in comparison, whether it be delicate acoustic music, or The Alan Parsons Project I fondly remember

Martyn, enjoy your vintage HL's for the lovely product they still are. The new ones are clearer and tidier, and so they should be, the work and experience that's gone into them, but that doesn't mean your oldies are outclassed, since the "family resemblance" should clearly be there, as it is in my relatively rough-n-ready rebuilt BC2's.

[A.S.]

...they did seem to build on the dearly beloved BC1, which was starting to sound just a bit thuddy/tubby, constricted and tired in comparison I recall back then, the bass just not being competitive as the competition improved. .... as it is in my relatively rough-n-ready rebuilt BC2's.

I think that was a general observation at the time.

What nobody really appreciated (or even wanted to believe) was that they were criticising the BC1 rather harshly for what was in actuality a design feature. The first question to ask of a speaker design is 'what is the target listening loudness?'. If the answer is that it is designed to be used in studio control rooms at a replay loudness rather lower than the studio staff would like because of general commotion in the studio and/or the close proximity of other studios and worries over bleed-through of noise from one to another, then it's a legitimate design decision to lift the bass end output of the speaker. That's because our ears perceive bass strongly correlated to loudness: if the loudness drops even a little, the bass subjectively diminishes rather more.

Take that same speaker, optimised for 75-80dB studio monitoring and place it in the untreated home listening environment, set the listener to 2 -3m away from it (rather than in the relative near field), connect it to an powerful amplifier, turn up the replay volume to 90-110dB and you have a recipe for boom and excessive warmth. What do you expect?

Re: BC2 .... that had a 1.5" voice coil hence more power handling than the 1" BC1 to pander to those home users determined to use the speaker at higher spls. But it was said that what the 1.5" voice coil gained in power handling it lost in midrange quality.

Unsure what questions to ask when considering new loudspeakers? No chance of a demo in your own home? Then ask the above question and it will give you a good starting point about the suitability of the loudspeaker for your needs. There is, of course, no perfect speaker, but a match between your listening loudness requirements (e.g. late at night, easily irritated neighbours) and the speaker design philosophy is the correct starting point.

As a class, the 'BBC monitor' is designed to sound full bodied and natural at a lower listening level than most other speakers due to it's application heritage. If you see pictures of speaker brands proudly boasting their rock and roll application or heritage against a backdrop of a huge studio and whaling guitars, avoid them like the plague. That implies that they have been optimised for high replay levels >>> 100dB and will sound gutless and bass light at home at a normal loudness. The ear has to be given a little assistance because none of use replay at home at anything like full concert loudness. This has been known for the best part of 100 years and you can read about ISO226 here.

ISO226: see the upward tipping curves in the low frequencies? See that the are not parallel to each other? See that at the threshold of hearing (bottom red line) for 20Hz to sound as equally loud as 1kHz (the pivot point) there needs to be a massive boost of about 60dB? It's the difference between those curves that (ideally) needs to be considered to make a transistor radio sound like a full orchestra .....

[Miles MG]

Re. the Audax tweeter mentioned, it is now available again. Falcon Acoustics supplied two brand new, made in France, HD 12 x 9 D25 models for my original HL Monitors. One tweeter had noticeably gone down in output, so I contacted Jerry Bloomfield ( whom I know) at Falcon. He shipped me a pair out and all was well again...

[Miles MG]

Thank you. When the output of one of my Audax tweeters on my HL Mk. 1s went noticeably down recently, I contacted Falcon Acoustics about replacements. They supply new Audax HD 12 x 9 D25 tweeters, plus voice coil / dome assemblies as mentioned above... The Audax tweeter phase question* was resolved by Jerry Bloomfield of Falcon.

He lives very close by me, the other side of Oxford. We discussed the 2Khz. question some time ago. Martyn Miles .

{Moderator's comment: *I think this means which signal wire goes to which terminal pins which is ambiguous on that tweeter? But as the Audax company closed down >15 years ago these units are not originals are they?}

[Miles MG]

Re. The Moderator's comment about the Audax tweeters. I advise he looks on the Falcon Acoustics website. The HD 12 x 9 D25 Jerry supplied are identical to the old ones, with the (well, it looked to me ) genuine Audax legends, etc. The comment re. Polarity was resolved, as mentioned. The HLs sound just as they did previously. After help from Andy Sinden of Harbeth re. the problem he emailed me to say the Audax units were unavailable. I contacted him after my HLs had been repaired and told him about Falcon Acoustics help, as other owners of HLs would wish to know where to source the tweeters for HLs needing replacements. I hope this clarifies the matter. M G Miles .

{Moderator's comment: Audax was (is?) a Harman International Group company. It would be nice to know the recent history of the brand/company.}

[quoro]

Would I notice much of a difference if I upgraded my Compact7ES to the latest ES3 spec? I only ask because after 8 years of my system being unchanged I recently upgraded my CD player and amplifier to a Naim Uniti2 and I just can't believe the improvement. Now I'm wondering if I can achieve a similar jump by changing my speakers. I've read there were quite a lot of improvements between ES2 and ES3, so am assuming there would be a worthwhile jump between ES and ES3. I live quite away from a dealer so thought I'd ask the question before making the trip. I love the Harbeth sound (or lack of it) and the C7ES has provided many years of sterling service (since 1998), but if there is an improvement to be had, well I've done the overtime and am willing to bolster the company's profits. Love the forum by the way!