JR-149 Speakers

designed by Jim Rogers

The JR149's were designed by Jim Rogers who worked as a Sound Engineer for the BBC. The Beeb used to use special monitor speakers to ensure quality and consistency in their audio output.

The high and low frequency drivers are the same as those in the famous LS3/5A speakers (the BBC monitors) - a B110 Bextrene woofer and a T27 tweeter, both by KEF. The cabinet itself is made of aluminium sheet, finished with wooden top and bottom covers, and a metal base. Different types of wood were available, some having a leather inlay.

Standard 6-sided box speakers have 3 pairs of resonant surfaces to create tonal imbalances and 'sound colouration'. They are top/bottom, left/right, and front/back. These types of box speakers are normally full of sound deadening fibre glass wool or wadding, and the internal walls have something like bituminous felt stuck to them.

The JR149's are cylindrical speakers, and the top and bottom ends are stressed by a threaded rod running from top to bottom, tightened with bottom mounted nuts. This makes them slightly concave, and effectively 'clamps' the sidewalls to reduce colouration, resonance and standing waves to a minimum. The result is a clear, natural, 'open' sound.

I think the JR149 are really smart looking speakers with excellent aesthetic appeal. They make excellent plant stands! The original brown foam grille (now long disintegrated) wraps round the aluminium cabinet, My JR149's have new foam grilles fitted. New grille foam can be bought from Wilmslow Audio in Leicester or South Coast Loudspeakers in Southampton.

In my opinion, the JR149 is in some ways better than the 35a. The former has a little bit more bass,I can't use the phrase bottom grunt since both speakers haven't got it! The JR149 has better spatial representation and also less strained when playing loud.At low volume both the JR149 and LS35a just won't boogie.However, add the JR Sub Woofer and turn the volume up and they really rock!

These speakers are not very efficient (because they have fairly high impedance) so you need an amplifier with a minimum output of 50W at 8 ohm. I drive them with an old QUAD 303.

I first saw/heard the JR149's at a Hi-Fi show in Harrogate in 1977 (I think), then I heard them again in 1978 or 9 with the JRSW sub woofer. Jim Rogers himself was proudly demonstrating them. I bought my JR149's when I was working in the Glasgow area in 1979, from a shop in Kirkintilloch or Bearsden (probably long gone). Then I got the JRSW a year later when I had saved some more pennies. I seem to recall that the JR149's were around £150 and the sub-woofer was about £250, and I was earning about £55 a week so it took me forever to save up for them.

Here is a copy of the original brochure for the JR149.

The JRSW sub woofer (bass unit) adds extra-ordinary depth and punch to the sound. It contains a fairly complex crossover network. Since low frequencies are non directional (i.e. mono), a standard speaker pair, each containing a woofer, is wasteful. A single, mono, sub woofer can be placed anywhere in the room (e.g. hidden out of sight) and the listener will never know. Any directional information is 'filled in' by the bass/midrange units in the stereo pair. So the amplifier outputs are cabled into the crossover in the JRSW, the low frequencies are extracted, converted to mono, and fed to the bass driver, while the mid and high frequencies are fed back out to the JR149's in stereo.

I'm sure that there was also a model available with a bass amplifier fitted (an active sub woofer) but I can't find anything about these. If you have any information, please email me on dave@davedixon.co.uk. There are loads of huge cables lying about the lounge. So the JRSW lives in a corner and pretends to be a table, and the cables go under the floor boards. (It's the only way to keep Wendy happy!).

The setup now sounds extremely sweet, and when the neighbours go out I can rattle the cobwebs out from under the floorboards. Warning: it is not recommended to stand expensive ornaments on the JRSW at high volumes while playing Supertramp!