Sunday, 30 December 2012

IMF TLS80 Transmission-Line Speaker




These are considered one of the best British speakers ever made, "Id go with that"

My first real speakers, I was 18 and handed over £400 for them. What a pair of speakers, nothing but music making machines. I had them setup in a basement once and I can honestly say they were nothing short of amazing. From the deepest bass to the highest crisps, these had it all. Perfect delivery, warm and subtle with all the detail. Sound-stage was huge, with sound wizzing around my head and I mean 360* around!



The real magic to these speakers is the bass. So smooth and deep without ever a booming note. Transmission-Line speakers are the one for me! Tried Cambridge R50 but not enough sub base and the sound was murky as hell. TLS50, I hated everything about them! It has to be the 80s every time. The perfect speaker... Until I found the IMF Studio... more on those later.

                

Drive Units
Bass:

Kef B139: 11 3/4" x 8 1/4" flat polystyrene diaphragm

Mid range:

Kef B110: 6" plastic cone containing in separate line

Tweeter:

Celestion HF-1300:

Super-tweeter: 
Celestion HF2000:

Crossover
4-way

Crossover points: 375 Hz , 3.5 kHz and 15 Khz

Frequency Range
20 Hz to beyond audibility


33 comments:

  1. There have been far superior speakers produced in the last 30 years. Yes these would have been gorgeous when new. Someones ears may have deteriated along with their speakers. So much myth around old speakers. dont be fooled

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    1. I don't see any real new technology in speakers for the last 30 years. Normal considering the esoteric Hifi companies size and durability. They have no money for real R&D.
      Someone mind may heve been deteriorated by pure marketing.
      Just compare "myth" old speakers and what you can buy new for the same price and let your ears decide.

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    2. couldn't have said it better myself, thanks.

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    3. What do you mean by "superior"? Speaker technology has in essence not changed in principle of being a sound radiator. Drive units have been changed in manufacture and so forth. Can you name me a make and model (non Transmission Line design)up to say £20K that has a frequency response of 20Hz to beyond audibility. We would all benefit from your knowledge.Please oblige us.

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  2. I still have my TLS80's, had the cross oevers redone and can't find a suitable replacement for under 10K

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    1. Nice one! Sadly mine have found a new home but at least I have the memories!

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  3. I bought my TLS80's back in 1976 for £320 from Largs in High Holborn. Still have heard nothing better -
    at least for home hi-fi. What did happen recently was that the Celestion 2000's gave up the ghost. Replaced them with Coles 4001 I think they're called. Sounds even better. Don't be tempted to drive them at very very high levels because the super-tweeters will blow. I think that's what happened to the original units. But the other units (bass treble and mid) are all still fine. I'm lucky enough to be able to drive them to high levels - but yes , the super tweeters will blow. Answer - turn the volume down a bit!!!

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  4. I used a pair of Rogers Studio Monitors for a long time because I liked them so much. Had good trebble and bass. Then I heard the IMF TLS 50 MkIIs. I bought them for the base performance with pipe organ music. Then stepped up to IMF TLS80 MkII, which I now thoroughly enjow for performance in the upper register as well as the pedal notes of organ music. I can feel the Cathedral/Church in my listening space.
    Probably the moderl TL PMC speakers would improve on these but at a price.

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  5. Id like to say a massive thank you to everyone for all the interest and comments on this article. Im glad to see a generally positive response here and hopefully you will enjoy the IMF Studio article coming soon.

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  6. So what about the IMF's studios?

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  7. Gorgeous speakers in both sound and looks. While they are roundly excellent TLS-80s are not perfect. The Celestion tweeter is a little bit peaky around 3000 hz due to some stored energy. It can give the speaker a bit of an explicit quality in the lower treble which enhances detail in some source material. The midrange has a slight cupped hands quality which is characteristic of certain bextrene drivers. These are minor carpings however and the ear tunes them out quickly as the TLS's 80s virtues grab your attention. One thing to be careful... because they are so big they give some people the impression they are capable of high volume levels. No they are not. The drivers (typical for british speakers in the 70s) are delicate, particularly the tweeters and the power handling and maximum SPL is no better that may British bookshelf speakers that use these tweeters, like Spendor, Rogers and B&W. These are not for metal heads but for most other kinds of music at sane listening levels the IMF TLS-80s will captivate if driven by top notch ancillaries and with attention paid to room acoustics and treatment.

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    1. Hi my name is Tony I purchased pair of tls80 2 in 1977. I have had thousands of enjoyable listening since. I paid 440 pounds for them . I require a super tweeter is this item still available ? And if so where from. Any help would be appreciated. P's. I was very lucky to visit IMF factory in high Wycombe before they folded and had a memorable tour and an hour in there demo studio. Thanks Tony.

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  8. Nice to read some positive comments about a British loudspeaker company that made such an impact on the hi fi scene in the seventies. Having grown up with my TLS50s which I bought for £320,00 in 1975 and enjoyed every minute of them playing every genre of my musical tastes e,g,soft rock,motown,country rock and a smattering of classical. 15 years ago I was offered a pair of 80s for the princely sum of £100.00 needless to say I bit the sellers hand off - had new crossovers made and installed by Wilmslow audio and renewed B139 and B110s - brand new from some guy in Wales --- installed and run in softly for 48 hrs and now sound like they used to.
    With the correct ancillaries and room placement remind me just why I love to listen to music, and have listened to Tannoy DC10s and Linn Isobariks, but always return to my prefered TLS80S for sheer enjoyment.

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  9. Just a question from a guy who consider buying a pair of TLS 80 mk2. What is different between TLS 80 and TLS 80 mk2? And witch year did they put the TLS 80 mk2 at the market?
    Do they sound any different kontra the TLS 80?

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    1. Qite a bit of difference, actually. Mostly in the crossover. The mark 2s are flatter, more dynamic and more accurate with better power handling. The older TLS 80s sound darker at treble frequencies and more blunted in general. Both have the awesome bass extension of a good transmission line.

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  10. I've had my TLS-50s since April 1975. I will never part with them. The same with my FONS CQ30 turntable and SME 3009 tonearm. The rest of my system, I have updated, but with the goal of maximizing sound quality from the IMFs.

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  11. My father recently passed away and I have 2 x IMF TLS80 speakers/cabinets still in their original boxes in top condition (plus the various amps and players). Not for me, any ideas where to sell please?

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    1. Your best bet is to get them on eBay, sell your items separately, take good photos and make sure they are 100% tested and working well. If you do this with all the items Im sure you will be very pleased with the results!

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    2. hi,I would be interested in them providing the price is right.

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    3. Maybe you would like to send me an email.

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    4. Hi Peter - not sure how I e-mail you as I don't have a google+ account but you can contact me on paul@thegaters.com. However, going away soon for a week (half term)

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  12. Hi. You wrote about the IMF TLS80's. Can I ask a couple of questions.
    You wrote that they were the perfect speaker.....until you found the IMF Studio (more about that later). I can't find the more later. Did you write any more about the Studio, as I'd be very interested to know more about them.
    I also have a pair of TLS 50's. I know you don't like them, but they are good in a domestic kitchen. But one tweeter has finally gone. The tiny wire broke. Do you know where I could get a replacement compatable or original (peerless) speaker or a pair.
    Many thanks.. John.

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  13. I find your final comment implying the Studio is even better than the TLS 80. My second pair of speakers was the Studio MK2(it was way superior to the MK1 which crossed over at 750 Hz rather than 375 Hz) after a pair of AR2As(later converted to AR2AXs). I did love my Studios especially after Bud Fried(Irving M Fried = IMF) improved them by adding doping on the mid-range(the guy who did it skipped it that month because he found it ugly) and after Bud redamped the mid-range line. I must admit I loved the Studio but I thought the TLS 80 a step up. I'll be very interested in your comments.

    I also owned TLS50s but it's really hard to compare the studio and TLS50 because of the long time lag between ownership. I sold my Studios to a friend. I can't recall what I did with my TLS50s. But I do recall using early pairs of B&W DM6s and Rogers LS3/5As as my next speakers.

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  14. I inherited a pair of TLS80 and TLS50 speakers along with two Ampzilla amplifiers. Any idea where I could sell this equipment? Thanks. williams.alex.paul@gmail.com

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  15. Shaun Patel 20 August 2015 18.38

    I have a pair of IMP TLS 50 II speakers for which I am looking a good home where they will be appreciated by music enthusiast.
    Anyone wishes to buy them please contact or let me know where I can sell them. Please contact me at spatel20@sky.com

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  17. Spoke about 18 months ago about my TLS80s and have subsequently read about the strife that other people get from their SWMBO and partners in as much that they're too big and ugly........ take up too much room bla bla bla.
    Well a while ago I was in two minds whether to downsize and utilise my Tannoy 613s and a sub woofer, and would you believe it......The wife threatened to leave with them if they went and talked me into keeping them........ saying that I'd regret it in the long run as nothing else under 5 grand would come anywhere close. Needless to say ; they're still here and still sounding superb. And this is why I've been happily married for the last 28 years.
    I'm coming up to 60 next April so they'll probably see me out anyway, but I suppose I could put them end to end and be buried in them B-) Big G.

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  18. I have a request for advice. But indulge me first with the story.
    1966, my wife and I married. I was interested in what was then "Hi-Fi" and bought from junk shops, individually, two mismatched mono speakers. The sheer size in pre-subwoofer days made them superior to anything smaller. For five years they dominated our litle London flat. The swinging sixties. Miniskirts, psychedelic shirts and the best rock bands that God ever gave us. My old speakers dominated party after party. Beatles to listen to, Stones to dance to. Inevitably came the move to suburbs and No 1 baby. Wife said the ugly speakers had to go. I could spend what was then an unreasonably big sock of cash. I could go just as big - five years of listening to the Rolling Stones had convinced her that for Satisfaction size really did matter (sorry, couldn't resist that one). So got these speakers, in England called "IMF Domestic Monitors". They were unbelievably good. Someone here has commented on the bass. It is strong and pure, reproducing the note accurately without one-note-boom and, yes, whatever the aficionados of separate subwoofers say, good bass does have some directionality. But years brought more daughters, a demanding career, and while the IMFs followed us faithfully through Surrey, Toronto, Minneapolis and Atlanta, they were each time a bit less fitting for main rooms, and so for a quarter of a century they have sulked in a finished basement - rarely fired up, but each time there was "wow". This year the breast cancer that had bitten my bride so hard just three years after we bought the IMFs came back for vengeance. After 40 years, metastatic cancer in the spine and bones. Debilitating on the physique and mobility and unremitting pain that, thank God, modern medicine has under control - at least for now. But sitting so long in the main room together, she asked for the IMFs to be brought up from their cavern. So I got the IMF up to the main floor (a feat in itself), wiped of the mold, replaced the grill cloth torn to shreds by cats, and put them where the rest of the room is just context. I connected up the Transcriptor Reference, put on Widor's Toccata and fired it all up. Amazing. The power, the effortless presence is all still there. I swear that with a good recording and a large room these things reproduce organ better than a cathedral – and I have heard quite a few cathedrals. But now comes the question.
    There is, to my ear, a slight lack of a certain definition, particularly on rock such as the riffs of "Money for Nothing" and classical violin. Not an absence of higher frequencies, rather that it feels like there should be more directness, more "attack". If I were to guess, it is as if the mid range frequency waves are slightly smoothed. I could develop several theories:
    1. That this problem is inherent in a transmission line design and/or part of the emphasis of bass in any design.
    2. That the mid-range speakers have deteriorated over 40 years.
    3. Others here have said that there has been little change in speaker design in the last few decades. This may be true, but surely there has been change in speaker materials. I seem to recall reading that there is now emphasis on stiffer cones, whereas the IMF’s midrange speakers are floppier than my….well let’s not go there! Interestingly, the big Kef bass speakers are very stiff. Should I just change the midranges?
    4. I recall in the seventies that muddiness introduced by crossovers was an intractable problem and I also seem to have read that there has been big advancement in crossover design. Should I change the crossovers?
    What I do not want to do is change the volume balance by, e.g., adding another mid-range speaker that destroys the principal beauty – strong low freq. On the other hand, I can just accept that these speakers, like me, are of another age and, again like me, be appreciated for what they are and not what they are not.
    Any comments would be appreciated. Thanks for humoring me.

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  19. I had a similar experience and re did the capacitors the speakers sound wonderful again, I bought a kit from Falcon acoustics

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  20. Anyone compare the IMF TLS 80's to the B&W 808's I have a chance to pick up a pair of the 808's and just wonder if it would actually be an upgrade?

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    1. I do not know the 808's, but comparing the fronts - the space taken up respectively by speakers and wood tells you a lot. The IMFs were designed to deliver musical balance and beauty at high or low volume, and they do by putting the cost into the structure of the cabinet, not multiple speaker drivers. Without giving a lecture on speaker design (which I can), the transmission line is arguably the best way to take a 300 hertz or so signal (upper levels of the bass sound) and pump it out of the front of the speaker driver while taking the sound at the back and putting it through a labyrinth that takes a 300th of a second to get through, so the rear sound comes out in the same phase as the next front wave. The 808's follow the more recent design of large number/massive speakers. It is mainly a marketing thing - started, I seem to recall, by Polk. If you turn up the volume VERY high they will produce a lot of sound, but however well designed, there are compromises on quality. Many would say that at normal volumes any quality loss is miniscule. But personally I believe that at normal volumes a single mid-range driver has to move more and accelerate to higher velocities to produce the same level of sound as two or three, and for me this delivers more bite in the sound. So the question is where do you live and what do you want to do? If you live in a condo or a duplex, I cannot see how you could reasonably turn the knob up sufficient to warrant the 808's. On the other hand, the IMFs have beauty, and will deliver more than enough volume for any typical room and small gathering, but if you are in an open plan McMansion and have parties, the IMF's can be overpowered and/or overdriven and the B&Ws would probably suit you better. B&W is still a great name.

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  21. Transmission line bass wins hands down. So I don't think anything else will give that magic on organ.
    If the crossovers haven't been touched, then received wisdom is that the capacitors will have almost certainly deteriorated by now to such an extent that changing them is likely to bring a noticeable improvement, and someone's already noted that Falcon would seem to be the place to go.

    I have a pair of IMF prof monitors, model name as given on them is unclear, but from everything I've researched I believe they are most probably in effect RSPM Mk 1, dating from late 1960s (with the earlier 'racetrack' style B139s, and long fibre wool not foam visible in the ports). When I bought them secondhand in about 1990, upgrading from my TLS50s I'd had since new in 1975, I was told they'd been fitted with upgraded crossovers. I've been very happy with them ever since, until trying some room correction software recently, during testing of which I found one of the supertweeters Made odd noises when the test tone was applied, and there was significant roll-off in both speakers at the high end, About 20dB down by 15khz, worse in the one with the odd supertweeter. The reality is that my hearing drops off similarly, however that means doubly reduced chance of hearing the top end. I plan to swap the supertweeters over to determine if the odd noises have a physical cause in one of them requiring replacement (when I'd change both), and also recap my crossover.

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  22. Back in the 70's I worked for Armstrong Audio, later on Soundcraft then broadcast manufacturers, so know a bit about quality sound. I have recently replaced my Armstrong 626 + Spendor BC1's with a matched pair of IMF TLS80'S powered by a revamped Quad 405-2 and 34 preamp. As long as you use high quality leads and cables and check the caps (CAPACITORS) in your gear when you listen to early 80's music or before the sound will be better than the gear it was recorded on, I know I built it.
    In my mind nothing sounds as good as it did 40 years ago anyway, thats because I had young ears! just enjoy the music now!

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