Goodmans Mezzo SL tweeter replacement?
First off, let me introduce myself;
I'm Christian, 18 years old from the Netherlands. I own a pair of Goodmans Mezzo SL loudspeakers made in England. My problem, recently one of the tweeters gave up, and I was wondering if anyone knows where I could get a replacement tweeter.
Thanks in advance,
Hi, and very welcome Chris.
Tweeter: Philips AD0100 polycarbonate dome (?).
Dragging up the past.
What excellent taste you have owning a pair of Mezzo SLs! They are close to being the best 2-way "bookshelf" speaker ever made. One of the reasons for this is that, in the real world, 2-way is always a compromise. As you want the woofer to 'sing' all the way up to where the tweeter takes over, yet still reproduce deep bass (and likewise want the tweeter to go low enough to meet the woofer yet produce clear, crisp highs) there is usually a compromise - or three!
Goodmans had an excellent approach to this problem - at least in the mid-70s, just before they started going downhill as a top-notch speaker manufacturer. They used one of their own very well regarded woofers - in this case a beautiful big 10" beast with a cast aluminium chassis and a real rubber surround. In a departure for Goodmans they then put it in a tuned ported enclosure - when all of their other speakers had been sealed boxes - acoustic suspension.
This allowed the woofer to go down nice and low but presented them with a problem; It wouldn't reproduce the higher midrange frequencies - just below where the tweeter comes in - that are normally the responsibility of the woofer in a 2-way system. Now, even though Goodmans made some well-regarded tweeters themselves they didn't have anything in their 'stable' that would go from 2Khz all the way up to 20KHz and beyond.
Their excellent DT3 1" soft dome tweeter which was used in the larger speakers of the same year and range; 1974/5 and "SL" of "Slim-Line" range, named for the thin metal strip all around the front of the speaker that makes the sides look a lot thinner and lighter than the one-inch think that they are. Well, the Magnum SL used their own DT3 tweeter (as well as some Philips 1" soft domes [ADA0100 being one model, as mentioned] when they ran out of DT3s - but that's another issue. ;) They were never used in the Mezzo SLs)
The DT3 - and the Philips replacement - both only sounded good from about 3 to 3.5KHz and higher. In fact the extra current that's present at 2KHz would have fried the voice-coils. (As I'm sure you know the lower the frequency the more energy is involved in reproducing it - Such that, in a 100W 3-way system the woofer might be rated at 80W, the squawker (mid-range) at 40W and the tweeter at 15 or 20W.)
This problem of making a woofer and tweeter 'meet up' while reproducing a large percentage of the frequency range used for audio - and still sound musical at the cross-over point - is the reason a lot of speakers go the 3-wat route.
So, as this was sadly a time when Goodmans were in the twilight years of their time (even though the name was sold, changed hands a few times and now graces low-end Korean 'plastic' stereo and home theatre equipment) Goodmans engineers looked outside of their own range for a high-frequency driver that would mate with their excellent cast-aluminium framed woofer and, between them, make a great full-range speaker.
Their search ended at SEAS (Scandinavian Electro-Acoustic Systems), a Norwegian manufacturer of high-end audio drivers which had appeared on the world stage about five years earlier (and continues to manufacture some of the best drivers in the world).
Their the Goodmans engineers found a SEAS 1.5" mid/tweeter, a driver with excellent characteristics that (with the help of some Goodmans crossover design magic) would play cleanly and flat down to a 2KHz cross-over point yet still go all the way to 20KHz. It was a marriage made in heaven! Two drivers from two different companies who were at the very top-end of the audio reproduction field.
One, Goodmans, at the end of it's reign as one of the best speaker manufacturers in the world for the last 50 years. Goodmans, who's pre-~1976 drivers are highly sought-after and can fetch much, much more than they cost new... And the other - SEAS, at that time just starting to mass-produce high-quality audio drivers - and now providing drivers for some of the best-known companies at the very pinnacle of Hi-Fi sound.
Gramophone Magazine was very impressed with the Mezzo SLs. Their reviewer said: "Distortion seemed abnormally low, however, and a slight boost in the bass (using the amplifier controls) produced an admirable bass/treble balance that was satisfactory for all types of music..... In performance, the system is very low on distortion and therefore deserves to be used in conjunction with high quality equipment." You might not know it but that's amazingly high praise for such a staid and restrained magazine.
So Chris, after my mini bio of Goodmans last days of greatness I'll answer your question for you (if you didn't get the answer from the text above); I'd say the only way you're going to get a replacement driver is either from ebay or by purchasing another pair of Mezzo SLs with one blown tweeter. In case you haven't looked at yours it's a SEAS type Dome H-087.
I hope that you still have these speakers and are successful in finding a replacement driver. You know above where I mentioned that tweeters can only handle low wattage? Well, that's the reason why Goodmans rated the Mezzo SL at "Maximum RMS 36W". There's a lot of energy at 2KHz (and below, as the 2nd order crossover used will allow quite a bit of lower frequency energy through too).
That big beautiful woofer can handle far more power than that but, due to the design and having a soft dome tweeter sing so low it's power must be watched carefully. It wasn't such a problem in the mid-70s when they were made as amplifiers tended to be lower wattage. However modern amps could very easily blow the tweeter - which is the reason that replacements are expensive and hard to find.
The best of luck to you - I hope that you still have those speakers as they were undoubtedly some of the best made and collectors are now paying more than they cost new (£448) for a good pair and I think that they'll only go up from there!
After my last post I was having a quick look at the SEAS website and discovered that they're making what is essentially a new version of the H-087. I dare say it would cost an arm and a leg but take a look at the X3-06 Exotic T35.
X3-06 EXOTIC T35
"The Exotic T35 is a classic dome midrange tweeter with high sensitivity and a smooth, extended frequency response.
A coated fabric dome with integral surround manufactured by Dr. K. Müller in Germany ensures excellent performance and consistency. This supplier was among the first in the world to offer fabric dome diaphragms, and did produce the diaphragm for the famous 1.5” Dome Tweeter H087, developed by Seas in 1968."
So this could well be a replacement for the H087 used in the Mezzo SL but, if you do use it I'd suggest replacing them both.
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