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Tannoy Edinburgh 3149 become Tannoy Edinburgh Monitor Gold 12 !!!

ToTo Man

the band not the dog
A few months ago I made the difficult decision to sell my Tannoy Lockwood Majors (fitted with MG15s) and revert to my Tannoy Edinburghs which I had ‘retired’ several years earlier. The Lockwoods are of great pedigree, however I just could not get on with them in my acoustically treated but modestly sized 4.2m x 3.8m x 3.25m room unless I applied Dirac room correction across the full frequency spectrum to smooth out the response. With correction applied, they were superb, probably the best sounding speakers I’ve owned, and in hindsight I was crazy to sell them. However, unfortunately I listen with my eyes almost as much as my ears, and I was very frustrated that I had an aesthetically beautiful (to my tastes at least!) pair of Edinburghs that I hadn’t enjoyed for years. I was also given an ultimatum to reduce the number of “wardrobe-sized speakers” in the house, so sadly the Lockwoods had to go…

I original retired the Edinburghs due to being unsatisfied with their bass output. Over time the surround of the 3149 driver stiffens and consequently raises the Fs significantly, necessitating either a re-cone or a long and arduous process of removing the incumbent doping compound and applying new doping compound. I chose a 3rd and perhaps more radical option; to buy a pair of XXLS400 subwoofers to fill in the missing lows! Once balanced with Dirac, this turned out to be one of the smartest moves I have made. I was now experiencing bass with a smoothness, speed and extension I hadn’t had with any of my previous loudspeakers including the DSP’d Lockwoods. However, the more I listened to the Edinburghs, the more I noticed other colourations, particularly in the mids around the crossover frequency. No problem I thought, I can fix this by applying Dirac to the mids and highs as well as the bass. To a large extent I was right; with full spectrum DSP applied the Edinburghs became much more neutral and transparent in the mids and highs, and the soundstage opened up superbly. However at higher SPLs, there was still an audible harshness that made extended listening quite fatiguing, and no matter how hard I tried I just couldn’t learn to love the sound.

I’m no expert, but as far as factory-built cabinets go, the Edinburgh enclosure seems very well made, and so with the right driver and crossover, I figured it must have the potential to be a stellar loudspeaker. Which got me thinking, what if I replaced the stock 3149 driver with vintage DC driver and crossover? After consulting a couple of Tannoy experts I was advised that the Monitor Gold 15 or HPD 385 would be ideal for the 200L distributed-ported Edinburgh enclosure. However, as a woodworking novice, I was less than enthusiastic about irreversibly enlarging the cutout in the beautiful cork baffle to accommodate a 15-inch driver, so I turned my attention to 12-inch units. After a very disappointing experience with a pair of recently serviced and re-foamed HPD 315s which turned out to be an extremely poor left/right sonic match, I elected to use a pair of Monitor Gold 12s which I'd stored away for a rainy day. Having never measured these, it came as a wonderful surprise to find them matched to ±1dB across most of the range. They are also the flattest of all the Tannoy drivers I have measured above 1kHz. Things looked very promising!

I was a fool to think that it would be a simple process of unbolting the 3149 driver and bolting in the MG12, in fact it couldn’t have been further from the truth! This is what I learned during the process: (1) The bolt holes of the two units don’t line up, so new holes need to be drilled for the MG12. (2) The rear basket of the MG12 is larger in diameter than the 3149, so the baffle cutout needs to be enlarged. (3) MGs are clearly not designed to be front-mounted, as the bolt-holes literally need to be drilled 1mm away from the edge of the cutout, which means if you make the cutout fractionally too big or you slip the drill then it’s game over. (4) The drill holes are so close to the edge of the cutout that conventional tee-nuts are extremely difficult to use to provide a thread for the bolt, so I instead inserted the bolts from the rear and screwed on conventional nuts from the front after the driver had been mounted on the bolts, - not as easy as it sounds!

Two weeks of hard graft and I now have one Edinburgh cabinet fitted with an MG12 driver and its associated LSU crossover. From early listening tests and measurements, I am chomping at the bit to get the other one done! I am very impressed with the sound; it’s transparent, clear, detailed but also punchy and has excellent depth and sense of scale. I’m actually surprised by the quantity of bass; it sits between my sealed Lancaster MG15 (which are too lean IMO) and the Lockwood Major MG15 (which were overbearing IMO) but is better controlled with more speed and less overhang. I don’t understand much about T/S parameters, my ignorant plan was just to “stick the MG12 in and hope for the best”, and the plan seems to have worked out well.

As you can see from the following graphs that compare the Edinburgh MG12 against the Lockwood Major MG15 and Lancaster MG15, the Edinburgh MG12 is the smoothest measuring of all of the Tannoy models I've had in this room, and to my ears it’s certainly the best sounding with the least amount of colouration. That doesn’t mean it’s perfect however. There is a broad -3dB trough between 100Hz and 500Hz which makes it sound just a touch thin and clinical. A quick experiment with parametric EQ to boost this region by a couple of dBs restores enough warmth to the sound without making it undesirably bloated, after which there is honestly nothing else I can fault with this loudspeaker. I was already intending to use Dirac to smooth out the sub-100Hz bass response and integrate my XXLS400 subs below 40Hz, so I’ll probably just extend the range it corrects up to 500Hz and call it good, as I really don’t think I can be bothered going down the rabbit hole of playing about with cabinet damping to see what effect this has on the trough, as taking the driver in and out is a PITA. Besides, it may well be caused by floor bounce, since the trough looks more like a series of peaks and dips rather than a flat shelf, in which case altering the cabinet damping will likely have no impact on this.

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As I write this I am currently listening to an intentionally mis-matched pair of Tannoys as my other Edinburgh cabinet undergoes its transformation. I have a Lancaster MG15 on the left channel and an Edinburgh MG12 on the right channel and I'm having a swell time! :) Played together in stereo it’s amazing the similarities these two loudspeakers share. Switch to mono and pan the balance left and right however and the differences become apparent: the Lancaster is superbly musical and engaging to listen to but is ultimately coloured through the bass and mids (i.e. you can hear the cabinet contributing to the sound); whereas the Edinburgh MG12 sounds more grown up and sophisticated, cleaner and more accurate, more solid and grander in scale. Both are excellent in their own way and I will definitely be hanging onto my Lancs as an investment as they are 100% mint (even still have their original boxes) and would be fab if not a touch indulgent in a second system. However, I dare say the Edinburgh MG12 will become my endgame reference speakers, at least as far as Tannoys are concerned.

Here’s a before and after pic of the Edinburgh with 3149 driver (left) and MG12 driver (right). The MG12 sadly doesn’t quite match the 3149’s cosmetic beauty, but that’s a small price to pay for a such a significant sonic improvement! Once I cover up the old bolt holes and missing areas of cork with a 3/4-inch wide “ring” facing of some sort around the driver it should hopefully look (almost) as pretty as before. Any ideas on what I could possibly make this ring out of would be greatly received??!!

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Very interesting. Are the 3149s hard-edge? Hard to tell from the pics. Looks like the MG12s are the hard-edge variant so I assume so if they both work well in the cabs. Very brave to do irreversible work on such nice cabinets it has to be said, I'm pretty sure I'd have chickened out and just had the 3149s properly reconed. So, are they better than the JR49s? ;-)
 
Yes 3149's are hard edged - same drivers as used in the SRM 12X series like the LGM/LRM's etc.

They look great, and agree that you're brave to modify the cabs but it sounds like it was worth the risk! Fab. I'd like to try my 10" HPD's in a pair of Prestige cabs if anyone has some hanging around in their garage ;)
 
Very interesting. Are the 3149s hard-edge? Hard to tell from the pics. Looks like the MG12s are the hard-edge variant so I assume so if they both work well in the cabs. Very brave to do irreversible work on such nice cabinets it has to be said, I'm pretty sure I'd have chickened out and just had the 3149s properly reconed. So, are they better than the JR49s? ;-)

Yes Tony, both drivers are hard-edged. The 3149s can be re-instated if need be, the hole only needed to be enlarged by 3mm all the way round so is still smaller than the front of the 3149 chassis. Not that I intend to do so, but it's good to keep the option available in the event that I should ever want/need to sell the Edinburghs and the buyer wanted them fitted with the original drivers.

The mess you see around the MG12 driver is behind where the 3149 sat. Some of the cork had stuck to the gasket on the driver and unfortunately lifted when the driver was removed, hence my intention to fit some sort of ring around the MG driver to camouflage this.

It took MANY hours of careful filing with a curved wood file and finishing with a sanding block to enlarge the hole, as it was vital to take baby steps and not to make the hole bigger than absolutely necessary, I'm literally talking fractions of mm's!

I'd have had the 3149s re-coned if I'd have been satisfied with their mid and treble performance but they sounded very coloured and phasey to my ears. The MGs are in a different league IMO.
 
Ah, the little SRMs. These never had any bass before the surrounds stiffened! I never realised they ended up in a domestic speaker as they were designed for very dead sunding 80s studios and can sound very dry and fierce in a home setting, especially with grippy modern solid state (they'd likely have been on the end of a Quad 303 or 405 in the studio). Even the big 2x15" FSMs give up at about 50Hz! The soft-edge K variants such as the ones in the GRF Memory seem far more house-trained. Surprised the HPDs faired so poorly, though pair matching really is the bane of Tannoy ownership. I'd pay £thousands for a pair of MG15s that were genuinely to spec and within 1db of each other. Mine get within about 2db with one roll-off control backed off a notch!
 
Good call... I have a bunch of vintage Tannoys to choose from including Golds Silvers and Reds...my favourite of many years now is butyl edged 12" Monitor Golds in huge inert cabs used with 12" Silver crossovers. Sound is just more spookily 'in the room' with the 12s. The silver crossovers btw run the bass cone wide open, the crossover only operating on the treble pressure unit...
 
The silvers don't have the notch filter for the horn resonance either do they? Doesn't that make things a bit 'crunchy' around 3-4kHz? By saying that the Japanese seem to think the 12" Silver is the best of all Tannoys, and I tend to agree with Japanese audiophiles far more than most others. They seem to like what I like!
 
I'd try some of this to patch/disguise where the cork has lifted https://www.amazon.co.uk/dp/B003MQ4CB2/?tag=pinkfishmedia-21
Theres probably even thinner stuff available in sheet form.

Pity you can't get that with irregular black mottling through it... I guess I could get creative with a black ink marker though! The cork needs to be as thin as possible, I've seen 0.8mm on eBay which is probably the thinnest available? I've actually managed to salvage some cork from the back of the 3149s so I should be able to patch some of this back in. What's the most appropriate glue for this, PVA or wood glue?
 
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Pity you can't get that with irregular black mottling through it... I guess I could get creative with a black ink marker though! The cork needs to be as thin as possible, I've seen 0.8mm on eBay which is probably the thinnest available? I've actually managed to salvage some cork from the back of the 3149s so I should be able to patch some of this back in. What's the most appropriate glue for this, PVA or wood glue?

Yeah Richard, a more extensive web search may find the proper pattern/thinner stuff.
If I'm not mistaken the stuff in the link is self adhesive but PVA, contact adhesive, copydex all will work.
 
The silvers don't have the notch filter for the horn resonance either do they? Doesn't that make things a bit 'crunchy' around 3-4kHz? By saying that the Japanese seem to think the 12" Silver is the best of all Tannoys, and I tend to agree with Japanese audiophiles far more than most others. They seem to like what I like!
Not a problem to me in my system...as it happens I have the 12" Silvers which go with the crossovers...going with the Golds was based partly on marginally prefering the sound but also the peace of mind not utilising such irreplacable drivers as the Silvers with spouse and teenagers using the system.
 
Was playing about with some sine waves today (as one does!) and noticed some audible harmonic distortion from my Right MG12 around 116Hz. So I got the REW equipment set up to take measurements from 1 metre distance and, sure enough, there is some distortion in the right driver at 116Hz. Is this something I should be concerned about?

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I’d maybe try again with the driver out of the cab as it could be a resonance or rattle at that freq.
 
I’d maybe try again with the driver out of the cab as it could be a resonance or rattle at that freq.

I can just picture my dad's face when I ask him to remove the driver from the cab as it's a real bugger to get back in without loosing the bolts inside the cab! :eek:

I sine swept the drivers last year before installing them in the cabs (I still have the graphs) and can confirm there is no distortion on them, so either you're right and something is sympathetically resonating, or else something untoward has happened to the driver and/or crossover between then and now. This is actually the first time I've properly sine swept the drivers since fitting them in the cabs. I've just been doing pink noise RTA out of laziness but of course this doesn't record distortion, so I don't actually know when the distortion first appeared.
 
I’d try: Leaking Gasket behind driver, uneven torque on bolts may be distorting the frame or try rotating the driver see if it clears. Spot of superglue on bolts /inside cab will hold then in place.
 
I’d try: Leaking Gasket behind driver, uneven torque on bolts may be distorting the frame or try rotating the driver see if it clears. Spot of superglue on bolts /inside cab will hold then in place.
Think you might be right. Applying pressure to the top edge of the driver reduces the distortion at 115Hz by about 7dB. I stubbornly didn't fit a gasket to the rear edge of the drivers before mounting them as I was concerned it would stick to and subsequently rip-off pieces of cork baffle like the stock 3149 drivers did. So it looks like I have egg on my face...
 
Pm me your address and I’ll pop some in post

PM sent. :)

PS - I've been enjoying this hobby since I was a teenager (I'm now 31), and have owned Tannoys in one form or another for the last 8 years, and this is honestly the most contented I have ever been with my system. I'm so relieved I turned down what was a very reasonable offer last year to sell the Edinburghs (avec 3149s) and instead embarked on the then unchartered territory of adapting the cabinets to accept my MG12s. It's turned out to be one of the smartest hifi moves I've made, as I would simply not have been able to afford what it would cost to buy an equivalent level of performance from a ready-made product.
 
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