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Revisiting Jim Rogers JR149s

Has anyone stacked two pairs of them?

If anyone is near me with a pair who wants to try, let me know. I’m in London, Wimbledon.
 
There's an interesting discussion taking place at the moment on TAOS with regards to using the Monacor SP-135TC as a replacement for the KEF B110 SP1003. I'm not sure if he's a member here, but I've encouraged the OP to check out the JR149 discussions on this forum.

Completely coincidentally, I spent yesterday afternoon measuring spare drive units I've acquired over the years. This doesn't strictly relate to the JR149 so if you wish to move this post to its own thread, Tony, I'll understand.

The drivers I measured included Audax HD100D25 tweeters (used in JR150 amongst others), KEF B110 SP1003 midbass units, IMF 5/36 midbass units (these were IMF's answer to the B110 which I'm guessing they developed either due to frustration with B110 production inconsistencies and/or wanting to reduce costs), Audax HD13 midbass units (used in JR150 amongst others), Monacor SP-135TC (I bought these to replace the Audax HD13 in my JR150). I'll just post the midbass driver results here as the tweeters aren't really relevant to any JR149 discussion!

The measurements were made in free-space with no baffle or enclosure so are of limited use, but may be of some value nevertheless. I took them at a distance of 1m and off-axis by about 0.4m (it's been a long-time since I did geometry, is that an 18 degree angle?). I measured off-axis because I started with the HD10025 tweeters and those all exhibited a sharp dip at 6kHz when measured on-axis.

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IMF 5/36 midbass units (these were IMF's answer to the B110 which I'm guessing they developed either due to frustration with B110 production inconsistencies and/or wanting to reduce costs),

Looking at the response my guess is IMF wanted to get shut of the nasty out of band resonance, which they appear to have done very successfully indeed. That is the bad point of the B110 for sure and the requirement for the notch filter.

On that general subject I’d rather like to see some crossover modelling for the LS3/5A just to see how that speaker’s notch filter compares to the 149. My suspicion is it must be deeper as I’ve never heard the slightest hint of a quack from 3/5As, whereas the 149s can have just a little hardness to the upper mid/low treble (violin can sound just a tiny bit edgy, though I’m being very critical here). My impression is 3/5As are a little smoother, but I don’t think they have the dynamic impact, bass or scale of 149s. I’d love to really compare them at great length sometime (I rather wish I’d bought a pair of Falcons when they were first introduced at £1.2k or whatever it was!).
 
Well yesterday I sadly took my JR149s out of my main system, have to say its been a very enjoyable 6 months listening to these amazing little speakers.

The naturalness of voice and sweet treble is what I really appreciate about and they actually do quite a good bass but ultimately you have to be careful about not turning up the wick too much. So I put my Tannoy precision 16.4 back in the system and what a disappointment
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So out of the loft came my Wilmslow Audio Classique soft dome version with the Volt BM 220.8 Bass Mid and Scanspeak D2905-9500 Tweeters, old school speakers and I loved these speakers for years and now I know why, they have much of the attributes of the 149s in great mid range sweet treble, great imaging and solid bass so these are keepers

JR149 not going to waste as they are now in my second system with my Rogers A100 Amp and T100 Tuner

Alan
 
Looking at the response my guess is IMF wanted to get shut of the nasty out of band resonance, which they appear to have done very successfully indeed. That is the bad point of the B110 for sure and the requirement for the notch filter.
To my layman's eyes, the 5/36 driver looks very similar to the B110, so I'm curious as to how IMF were able to avoid that resonance when KEF seemingly weren't?!

https://www.falconacoustics.co.uk/imf-5-36.html
 
THAT'S 'classic'!!!!

At the risk of going off topic, is their another source apart from the T100 and is it period correct?

Jim
Unfortunately not, my Garrard 401 is in the loft but this system is also plugged into my digital system via a computer and Synology NAS so can replay all my digital music via JRiver Media player and still sound's amazing due to the JR149 speakers

Alan
 
I know for sure that JR149 speakers used Focal 5N401 woofers, not KEF B110.
It was actually Focal’s first customer!
 
I know for sure that JR149 speakers used Focal 5N401 woofers, not KEF B110.
It was actually Focal’s first customer!

Only the JR149 MkII (thinner top and bottom panels, no metal base). The original version used the T27 and B110.
 
The interesting question with these is whether the Type 24 crossover is a good or a bad thing.
This has been discussed already to some extent in this thread. I had Hartle's Type 24 crossovers and was fooled for some considerable time into believing they were an improvement over the originals, but they weren't. They're voiced with a more forward upper midrange which reduces the perception of depth and also makes the top octave sound drier and less airy. Also, they don't have the same baffle step correction as the originals so have weaker bass output. I uploaded measurements comparing their frequency response with the stock crossovers. See posts #298, #302 and #304. The Type 24's saving grace is that it's made to much closer tolerances than the original crossovers and so should give better pair matching (assuming your drivers are well matched in the first place).
 
But they still sound awful and remove the sparkle of the originals, I have a pair languishing in the shed never to see light of day.
I'm only pleased that I'm not the only one to have realised their flaws.
 
I stand corrected then Tony!
I’ve only seen mkII versions, probably.
That's interesting as here in the UK the number of mk1's greatly outnumber the mk2's. For every ten mk1's I see on the used market, I'm lucky if I see one mk2. Which country are you in?
 
But they still sound awful and remove the sparkle of the originals, I have a pair languishing in the shed never to see light of day.
I'm only pleased that I'm not the only one to have realised their flaws.

Never heard the T24, but looking at ToTo Man’s measurements they certainly take things in the wrong direction to my eyes. I’d love to really understand the story behind them and how close to Jim Rogers’ design the aftermarket ones actually are. I have huge respect for Rogers and can’t imagine he would have made them worse, so my guess is something has been lost in translation somewhere, e.g. they were designed for different drivers, for use with a sub, something like that. They were never officially released by JR, so I’m sure there is more to this story than we know.
 
That's interesting as here in the UK the number of mk1's greatly outnumber the mk2's. For every ten mk1's I see on the used market, I'm lucky if I see one mk2. Which country are you in?

France, where Focal has manufactured loudspeaker units for 40 years.
 
This has been discussed already to some extent in this thread. I had Hartle's Type 24 crossovers and was fooled for some considerable time into believing they were an improvement over the originals, but they weren't. They're voiced with a more forward upper midrange which reduces the perception of depth and also makes the top octave sound drier and less airy. Also, they don't have the same baffle step correction as the originals so have weaker bass output. I uploaded measurements comparing their frequency response with the stock crossovers. See posts #298, #302 and #304. The Type 24's saving grace is that it's made to much closer tolerances than the original crossovers and so should give better pair matching (assuming your drivers are well matched in the first place).

Any less baffle step than the original and they'd need to be wedged against the wall Kan-style.
 
Regarding the type 24 crossover ( and this is hearsay from a very reliable source ) Jim Rogers did design them and I believe he was going to offer them to the market as an 'upgrade'. Which version of the speaker he had in mind, I don't know. How Graham Hartle got hold of the design I don't know, but do know he was in frequent contact with Jim Rogers, whether this was social or semi professional as Graham was a cabinet maker by trade and I saw quite a few of his cabinets and cabinet re-works. My 'source' , sadly no longer of this earth so I cannot verify the above and must rely on memory was a well respected and knowledgeable Kef enthusiast over on the forum hifi loudspeakers, he assisted Graham in hand winding the inductors of the type 24 crossover and assembling them. His comment regarding the crossover was that ' it smooths them out', but did not commit to an opinion.
That I'm afraid is the limit of my knowledge regarding the Type 24's and unfortunately punctuated with too many ' don't knows '
 


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