For Sale a pair of large floor standing Transmission Line loudspeakers from the mid 70s carefully constructed to the Hi Fi answers design by C. J. Rogers featuring a multi folded transmission line labyrinth with long haired natural wool damping.
Size 1000mm High x 405mm Wide x 470 mm Deep. Weight 48Kg each
They are fitted with the following drivers and base mounted crossover units:-
Bass KEF B139 SP1044
Mid KEF B110 SP1003
Tweeter Audax TW025MI (replaces original KEF T27)
Supertweeter Coles ITT-STC 4001G
Crossovers Separate Bass and Treble boards with Solen Audio Grade Caps in treble section wired in sonic link cable throughout. Crossover frequencies 375Hz, 3kHz, 10kHz.
These speakers produce a huge soundstage with an effortless deep bass and very detailed treble. They are in full working order and have been in daily use until being replaced with active Naim S-600s a couple of years ago.
I would prefer to sell them as complete loudspeakers but I can remove the drive units and crossovers as a job lot if required.
Looking for £350 mainly due to the value of the drive units.
The speakers are located in East Yorkshire UK. Carriage costs to be determined by arrangement.
Please PM me for further details. Hopefully some photos should follow.
Size 1000mm High x 405mm Wide x 470 mm Deep. Weight 48Kg each
They are fitted with the following drivers and base mounted crossover units:-
Bass KEF B139 SP1044
Mid KEF B110 SP1003
Tweeter Audax TW025MI (replaces original KEF T27)
Supertweeter Coles ITT-STC 4001G
Crossovers Separate Bass and Treble boards with Solen Audio Grade Caps in treble section wired in sonic link cable throughout. Crossover frequencies 375Hz, 3kHz, 10kHz.
These speakers produce a huge soundstage with an effortless deep bass and very detailed treble. They are in full working order and have been in daily use until being replaced with active Naim S-600s a couple of years ago.
I would prefer to sell them as complete loudspeakers but I can remove the drive units and crossovers as a job lot if required.
Looking for £350 mainly due to the value of the drive units.
The speakers are located in East Yorkshire UK. Carriage costs to be determined by arrangement.
Please PM me for further details. Hopefully some photos should follow.
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An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
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Do you have more info on the article? These are obviously different than the well known Rogers Pro9TL also published in HiFi Answers.
dave
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Hi planet10, they are essentially the same speaker but that’s the first time I’ve heard the Rogers Pro9Tl reference.
A friend and I made two pairs of these. The first pair exactly the same as Mr Rogers diagram above with the bass driver vertical at 13 1/2 '' cabinet width and a 3'' x 10'' front vent. They were very good but did not have quite the depth of bass I was looking for.
The second pair are the same design but housed in a 2 ½’’wider cabinet with the bass driver mounted horizontal giving an increased TL volume. This produced a much deeper tuneful bass but required the TL end port area reducing slightly. This also helped the rigidity of the baffle board.
This modification was not an official Hi Fi Answers change but my own preference. In the original article Mr Rogers does state the horn dimensions were not as critical as first thought, although I believe he was refering to the quarter wavelength length rather than the cross sectional area.
A friend and I made two pairs of these. The first pair exactly the same as Mr Rogers diagram above with the bass driver vertical at 13 1/2 '' cabinet width and a 3'' x 10'' front vent. They were very good but did not have quite the depth of bass I was looking for.
The second pair are the same design but housed in a 2 ½’’wider cabinet with the bass driver mounted horizontal giving an increased TL volume. This produced a much deeper tuneful bass but required the TL end port area reducing slightly. This also helped the rigidity of the baffle board.
This modification was not an official Hi Fi Answers change but my own preference. In the original article Mr Rogers does state the horn dimensions were not as critical as first thought, although I believe he was refering to the quarter wavelength length rather than the cross sectional area.
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Thanx... so you increased the volume and mass-loaded the line. Done right should indeed increase bass and reduce ripple.
dave
dave
I would love to own these, but they are too far away. Beautiful! They remind me of IMF. Good luck!
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