MY STORY

Tannoy Monitor Gold 15″ (LSU/HF/15/8) were on my wish list since I discovered coaxial speakers and the theory behind putting two drivers on one axis. Couple of years ago I have become a lucky owner of these beautiful drivers. They were bought from London, from the first owner who in 1968 bought them in Lancaster enclosures. The gentleman used them in his private recording studio for couple of years during 70s. Afterwards, drivers were taken out of the enclosures, with an intention of building better ones. This has never happened, and for over 30 years these drivers were waiting for me in storage.

When I first plugged in these monster drivers housed in hardly optimized test cabinets I was very impressed with their sound. And this was while using crossovers with old electrolytic capacitors. Many hours of soldering and even more hours of wood working after, I was able to test these drivers with crossovers based on very good quality components and in heavy, sand filled, 25mm thick plywood, 210l bass reflex enclosures. More about building of these cabinets can be found in DIY section of this page.

As you’ve probably gathered by now, I bought these drivers without any enclosures so I was not able to review any particular model of vintage Tannoy speakers that use Monitor Gold drivers (for instance Lancaster or York). Nonetheless, from what I have heard, Tannoy enclosures from the basic range are not very rigid and people who buy them, sooner or later replace them with better quality DIY cabinets. Having heard Tannoy Monitor Gold drivers in many different closed and bass reflex enclosures, I am confident that the cabinets used for this review allowed the drivers to show their character and sound qualities.

Please note that purchasing vintage speakers is always a gamble. 50 years it’s a long time, and one can never be sure how this time affected the loudspeaker drivers. Consequently, it is possible that the Tannoy Monitor Gold that you have purchased will measure and sound different than the pair I reviewed.

tannoy monitor gold 15 speakers review 01 in enclosures

tannoy monitor gold 15 speakers review 02 in enclosures

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SPEAKER INFO

Model History

Tannoy Monitor Gold 15″ are the largest (and most expensive) drivers in the Monitor Gold range. The “Monitor Gold 15″ is a common name, but their factory model name is LSU/HF/15/8. These drivers were are successors to Tannoy Monitor Red 15”, and were first launched in 1967. The reviewed pair is from 1968, therefore, from the second year of production.

Tannoy Monitor Gold range was very popular in recording studios in 1970s. Many famous studios (including Abbey Road in London) used these speakers for mixing – check the photo of the left showing a pair of Tannoy Lancasters, presumably with MG15 inside. Numerous legendary albums were mixed using these speakers, so if you have a pair at home, you may be hearing the recording in a very similar way to the person who mixed it (this isn’t always a good news though ;). Also, I have found something that indicates that some of the recording studios may have been using these speakers in more modern times too. The photo on the right is an inner front cover of the Marchin’ Already album by Ocean Colour Scene. Looks familiar? This album was record in 1997. Apart from studio monitoring, these drivers were also used in higher end of domestic market. They were used in large horn loaded enclosures such as Tannoy GRF, Tannoy GRF Professional, and Tannoy Autograph.

Design

These drivers feature unique ‘Dual Concentric’ construction (visible on the scan of the sales brochure below), which ultimately means that we have two drivers (tweeter and woofer) combined in one driver and working on the same axis. This itself would not be so unique as there are many other coaxial drivers out there, however, in Tannoys, the tweeter diaphragm is placed behind the bass driver’s magnet, and the same magnet is used to power both – the woofer and the tweeter diaphragms. Furthermore, the tweeter diaphragm is in inverted position and it is enclosed in a chamber that turns it into a compression driver. The airwaves produced by it travel through the ‘Pepper Pot’ phase plug, and then, they are acoustically amplified in the metal horn throat (inside the magnet), and then, amplified further by the bass diaphragm, which acts as a horn extension.

Horns can usually be fond in the PA speakers, however, there are number of HiFi manufacturers that use horns with very good results (e.g. Klipsch, JBL, Altec, Lowther) and Tannoy is one of them. This is a rather basic description, but it gives a good overview of how these drivers work. People who are into DIY may find it strange, that a heavy and large woofer cone is crossing over with fairly small and efficient HF unit at 1kHz. This contradicts best practices that can be found in many loudspeaker building books, and yet, it seems to work here.

Having two diaphragms on one axis (in theory) should result in better pin point imaging than in traditional speaker designs. This is because the whole frequency range originates at one point source of sound, instead of coming from two or three different drivers placed somewhere on the speaker front baffle.

Amplification

Many people, probably due to relatively high sensitivity of these drivers, suggest using them with valve amps. From what I have read, these drivers were designed with transistor amps in mind, hence their 8 ohm nominal impedance. I’ve tried them with both, valve and transistor amps, and I much prefer their sound with good transistor, mainly due to better dynamics and bass control.

TANNOY MONITOR GOLD 15 SPECS

Frequency Response:	23 – 20,000Hz
Sensitivity:	92dB
Impedance:	8Ω (5Ω min.)
Power Capacity:	50W
High & Low Frequency Driver:	LSU/HF/15/8 380mm (15″) Dual Concentric with 51mm (2″) Aluminium Dome Compression Driver and 380mm (15″) Paper Diaphragm
Crossover Frequencies:	1,000Hz
Free Air Resonance (FS):	26Hz
Weight:	10kg (each driver)

Production Year:	1968
Price When Launched:	£84 for a pair
Equivalent Present Day Price:	£1,380 for a pair
Current UK Price:	£1,300 to £1800 for a pair

LOOK & FEEL OF TANNOY MONITOR GOLD 15″ DRIVERS

These drivers, 46 years after they were made, still look very impressive. The baskets are made from a very rigid die cast alloy and are stove enamelled. Bass diaphragms are made of paper, with diaphragm suspension being an extension of the actual diaphragm and coated with rubbery looking substance (presumably to aid with cone termination and to tune resonance frequency to the desired level).
The throat of the tweeter horn is made of untreated metal, which when mixed with humid British weather, often results in minor oxidation on the throat surface (not ideal).
The motors are rather large alnico magnets hidden under gold plastic covers. The crossovers are nicely soldered, using components available at the time when these were made. Wires, sockets and plugs are rather low quality by modern standards, however, they were probably OK back in the day. Overall, despite the pitfalls, really impressive drivers. Playing with these drivers was like playing with an old Jaguar E Type – classic beauty. Photos below present the drivers after the upgrade of 4 pin sockets.

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SOUND OF TANNOY MONITOR GOLD 15″

First Impressions

When I connected these rather large loudspeakers drivers for the first time they were very overwhelming… in a good way though, as the presentation of the sound was very different to what I experienced with most speakers previously. The soundstage was a wall of sound, much bigger than on most loudspeakers. Positioning and separation of the instruments was good but the depth appeared to be rather limited.

Bass

It’s hard to not be impressed but the bass of these Tannoy Monitor Gold drivers, especially when one is used to listening to modern tower speakers. There seems to be something special how these 15in diaphragms energise the room. When I first heard double bass from Temptation by Diana Krall, I was really blown away. Bass appears to be very dynamic and tactile. Feeling the physical impact of the sound is not something that people are used to these days, especially people who use stand mount monitors for playback. The bass appears to be quite meaty and well controlled. And in these 210L bass reflex cabinets, goes deep, very deep. Even at 35Hz using signal generator you can clearly hear the sound.

Midrange and Treble

Midrange and treble sound good, being very sweet and easy to listen to. However, it is not all rosy. Tannoy Monitor Gold 15″ are not the most detailed speakers in the world. I remember when I first compared them side by side with Celestion Ditton 66 and was really surprised how much more details I could here on Celestions. Saying that, even though there are many loudspekers with higher resolution than these Tannoy Monitor Gold, there are not many that are capable of delivering this full bodied sweet sound. What these Tannoys do best is saxophones, lower ranges on stringed instruments, and vocals. I have not yet been moved so much by My Romance by Ben Webster on any other speakers. Just bear in mind that are not the most truthful presenters. They definitely add their flavour to the sound. However, don’t be put off by this, as this is part of their character, and part of what makes these Monitor Golds what they are.

Soundstage

Tannoy Monitor Gold 15″ speakers struggle when depth of the soundstage and separation play an important role in our perception of the performance. I’ve experienced that with Needed Time by Eric Bibb and Auberge by Chris Rea, where the illusion of depth was very limited in comparison to other speakers. There are other speaker within this price range that can deliver much deeper soundstage illusion and give you a more immersive experience. However, that is not to say that these Tannoy speakers are not engaging. Even though the soundstage depth illusion is not the best, Tannoy Monitor Gold 15″ are still very engaging and enjoyable to listen to.

CONCLUSION

Tannoy Monitor Gold drivers are very musical and easy on the ears. Not the most detailed, and the soundstage depth is far from ideal, but despite these pitfalls, very enjoyable to listen to. Overall, sweet sound, with a lot of kick and energy to it.