Revisiting Jim Rogers JR149s
Martyn Miles
pfm Member
I owned a pair of S3/5R2 for a while. They became available at a good price and I knew I could sell them on
easily if I wanted to.
As a fan ( and former owner ) of various LS3/5as, I felt the little Spendors were a viable alternative. OK, the bass
end was not so pronounced, but that smoothness was addictive.
If I didn’t now own Harbeth P3-ESRs I could certainly live long term with the Spendors.
Good as they are, the little Harbeths have that extra ‘something’, in terms of insight, sense of scale and sheer
musicality.
I did sell the Spendors on in the end, but do miss their special qualities...
easily if I wanted to.
As a fan ( and former owner ) of various LS3/5as, I felt the little Spendors were a viable alternative. OK, the bass
end was not so pronounced, but that smoothness was addictive.
If I didn’t now own Harbeth P3-ESRs I could certainly live long term with the Spendors.
Good as they are, the little Harbeths have that extra ‘something’, in terms of insight, sense of scale and sheer
musicality.
I did sell the Spendors on in the end, but do miss their special qualities...
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mandryka
pfm Member
https://www.hifiloudspeakers.info/s...&start=0&sid=eddb3e9b948f6d416e7718be796aa970
A comment in the above discussion caught my attention
If it’s true I wonder if these changes effected the sound, or indeed how well the speakers have worn.
A comment in the above discussion caught my attention
If it’s true I wonder if these changes effected the sound, or indeed how well the speakers have worn.
Tony L
Administrator
Looking at the impedance plots on Stereophile for the SE and R2 I guess it is safe to assume the R is similar. I’ll switch the Leak back to the 16 Ohm tap and see what that’s like. I definitely prefer the 16 Ohm tap with the 149s, though they don’t dip below 8 Ohms (Gramophone plot on my Flickr here). If they sound good it will make running a couple of comparative REW measurements far easier as the playing field and amp output will be identical.
To my knowledge there was no cabinet design change in the original JR149 (i.e. the T27, B110 variant) beyond some deadsheet and foam added to the front around the time of the logo change from red to gold. This almost certainly being to address diffraction (the tweeter doesn’t like the over-hanging top-cap). The crossover fuse arrived at this time too. I am certain the thin, comparatively light and very well damped cabs of the 149 play a very big part in their wonderfully open and free sound. They are light enough not to store much energy, but don’t resonate either. Seriously clever cabs!
I know nothing about the later JR149 MkII or JR150. I’ve never heard either. I suspect the cabinet comments refer to these, but I do firmly believe light is good when it comes to speaker cabs, so it may be entirely wrong to associate it with cost cutting if it did occur. Jim might well have just found a way to do things differently. The 149 MkII is a potentially interesting speaker, though sadly relies on entirely unobtainable drivers so a bit too much of a risk for me!
ToTo Man
the band not the dog
That comment isn't entirely correct. I've had four or five pairs of JR149s, three pairs of JR150s, and three pairs of JR149 mk2s over the years, and saw no change in the thickness of the chipboard end caps between earlier and later serial numbers.
The 149 mk2 does have thinner end caps than the original 149, but I suspect the motivation for this wasn't cost-cutting (or at least not entirely) as the aluminium enclosure is taller, the net effect of this being a gain in internal volume without much of a noticeable increase in external dimension. I'm not sure how much of a cost saving there would be in thinner end caps. Chipboard isn't exactly an expensive material, and still requires veneering regardless of thickness. I suspect the biggest opportunity for saving money would have been the switch from KEF drivers to Focal and Scanspeak units in the 149 mk2. I read this was the motivation for using Audax drivers in the JR150 instead of KEF.
On the subject of 149 vs 149 mk2, I've written a comparison on this thread before, but IMO the 149 mk2 is a genuine sleeper, I really rate it. It shares many qualities with the original 149 but surpasses it on overall transparency IMO. It is, to my ears, less coloured through the midrange and more revealing up top than the original 149. If I had to choose one for monitoring purposes it would definitely be the mk2 but I can see why many would prefer the timbre of the original 149 as the mk2 is arguably a bit more analytical/sterile than its predecessor. The mk2 was well received by HiFi News:
http://mcmullon.com/icollect/hi_fi/jim_rogers/jr/Hi-Fi_News04.jpg
http://mcmullon.com/icollect/hi_fi/jim_rogers/jr/Hi-Fi_News05.jpg
http://mcmullon.com/icollect/hi_fi/jim_rogers/jr/Hi-Fi_News06.jpg
The JR150 is a different beast as it uses two midbass units in parallel covering the same frequencies. There is also greater distance between the Audax tweeter and first Audax midbass unit. These two features make it unsuited to nearfield listening. The 150 was designed to drive the listening room better than the 149, hence the twin bass units and larger enclosure. However, it is not a speaker I'd attempt listening to in a large room at farfield distance due to the inherent excursion limitations of the 5-inch Audax midbass units. I should note that my experience with JR150s has been from 2005 onwards, some 25 years after their release, so ageing could well have caused the suspension of the Audax midbass units to weaken over time. Therefore it is quite possible that they were able to handle higher SPLs when they were younger so to speak.
The Audax tweeter in the 150 has a rising response above 8kHz (a bit like Tannoys!) but this can be ameliorated by toeing the enclosure inward or outward to provide an off-axis listening position. There is also a -2dB HF attenuation switch on the crossover to reduce the overall level of the tweeter if desired, unlike the JR149/149mk2 which provides a continuously variable trimpot.
The 150 received only lukewarm feedback by reviewers on its release, and until recently I'd have ranked it a distant third with regards to timbral accuracy and overall clarity/transparency. However the pair I bought earlier this year are the best of the three pairs of JR150s I've heard and narrow the gap to the 149 considerably.
Finally, it's worth noting that ALL of the JR149, JR149 mk2 and JR150 I have owned or heard have sounded different to each other, some drastically so. The biggest variations I heard were between different pairs of 149s, while the smallest were between different pairs of 149 mk2s. This demonstrates that driver and crossover condition is key to any comparison, and that it is potentially very easy to form to a misguided opinion when auditioning a pair of loudspeakers that are unknowingly out of spec...
ToTo Man
the band not the dog
By servicing I presume you mean re-capping the crossovers? That's a good idea especially on crossovers that have ELCAPs, but does not necessarily guarantee that your speakers will be returned to sounding as they did when they left the factory. IME with the original JR149 and JR150, driver condition is the dominant factor. I re-capped a particular pair of JR149s because they sounded a bit shut-in, and the recap made no difference whatsoever in that case. Another pair of JR149s I bought had a huge broad plateaux in their midrange and sounded like a ghastly PA speaker. I didn't get to the bottom of that one but I suspect the drivers must have drifted way off-spec as the crossover components were all original and I doubt could have drifted enough to cause an anomaly of that magnitude. If you're happy with the sound of your JR149s as they are just now and don't hear anything objectionable or offensive then chances are your drivers are fine and I wouldn't worry. A recap may or may not bring some slight improvement but for peace of mind I'd do it anyway as it's unlikely to cause any harm.
Arkless Electronics
Trade: Amp design and repairs.
10W into 16R = 12.7V
10W into 8R = 8.9V
10W into 4R = 6.3V
10W into 8R = 8.9V
10W into 4R = 6.3V
Tony L
Administrator
Thanks, that is useful. It actually means my earlier 3.5V reading represents even less of the amps potential equating to about 0.7 Watt at 16 Ohms. I’ve just switched to the 16 Ohm tap and the Spendors, like the 149s, definitely seem to prefer it. Just more open and ‘alive’. I’m playing the Bill Evans and it really does sound very good! In the context I’m using I seem to have plenty of headroom, which is great to know. The Fluke meter is great, it gives a min, max and average value, so I’m confident I’m capturing peaks etc (I’ve only been quoting the max here).
Arkless Electronics
Trade: Amp design and repairs.
It all depends on the actual speaker impedance and at what frequencies you are measuring it of course...
If you use the 16R taps and the speakers are 8R then the amp will try to give a max power of 20W but obviously can't do it into that load and will probably run out of steam at maybe 6-7W and with greater distortion. If speakers are actually say 12-14R then 16R tap can be best compromise, but at frequencies where the speaker drops to an actual 8R... or maybe 6R impedance... Hence, as you will no doubt be aware, it's rather a compromise and eg if the speaker were 14R for much of the range but dropped to say 6-7R for most of the bass area, where the most power is needed, then 8R could be a better compromise. Horses for courses. Use ears in conjunction with impedance graphs!
Tony L
Administrator
That all makes sense, and if you look at the impedance plots for the 149s and Spendors they both go very high indeed, but not below 8 Ohms for the former, and 6 for the latter. The thing I’ve established here is I’m absolutely nowhere near the Leak’s limits here regardless of impedance, in fact I’d now be astonished if I’ve ever stuck more than a Watt and a half into either pair of speakers. I’ve just been playing the Spendors far louder than I ever would in normal use and got to 4V (peak), so 1 Watt into 16 Ohms according to the calc I linked to a page back. Even if the amp can only squeeze out 6 Watts into 6 Ohms, I’ll never get anywhere near that limit.
A few years ago a certain active loudspeaker salesman of distinctly non-scientific repute kept on threadcrapping all over the site claiming his little speakers had 400 Watt amp packs (they didn’t) and that you needed that amount to avoid clipping. I called ‘bollocks’ at the time arguing you’d be able to weld the voice coil rigid with 30 or less! Fun days, older pfm members will remember it well...
A few years ago a certain active loudspeaker salesman of distinctly non-scientific repute kept on threadcrapping all over the site claiming his little speakers had 400 Watt amp packs (they didn’t) and that you needed that amount to avoid clipping. I called ‘bollocks’ at the time arguing you’d be able to weld the voice coil rigid with 30 or less! Fun days, older pfm members will remember it well...
ToTo Man
the band not the dog
Interesting. The Spendors appear to dig just as deep as the JRs but have a less forward tuning with lower output above 2kHz. Do you have a graph comparing just one channel driven?
Here's what REW has to say! Both channels driven measured from my bean-bag listening seat. On paper two very similar little speakers!
PS no change in level, so that reflects the efficiency too.
Tony L
Administrator
That’s all I did. I’m still a subjectivist at heart so really only measure what I actually hear. I don’t listen at 1 meter on tweeter axis, so its just of no interest to me. By saying that I’ll inevitably be going back and forth a bit over the next month or so, so if there is any specific measurement you want to see I can easily do it.
Subjectively it aligns. The JR149s are a good click or two louder, they sound a little more dynamic and crisper as there is more crack to the snare, detail on brush-work, cymbals etc, but they are both really superb speakers IMO. Far more alike than different. I’m actually amazed how identical the bass is! That shows just how much is the room. Both sound great in the bass, I have no booms, honks or anything, and it is a fast, agile and musical sound, very easy to follow basslines etc.
I just don’t understand enough about REW to know how to dial room effects out, so again if you give detailed instructions I may be able to get something more generally useful.
PS One other thing worth clarifying is the JR149 tweeter level is where I decided I liked it the best! It is actually quite a bit of cut from its midpoint (about an hour and a half on a clock face), but I could back it off further if I wished. They sound right to me, I’ve tried more and less cut. The Spendors sound right too though, their treble balance is definitely gentler, but very nice and really suits a lot of stuff.
Subjectively it aligns. The JR149s are a good click or two louder, they sound a little more dynamic and crisper as there is more crack to the snare, detail on brush-work, cymbals etc, but they are both really superb speakers IMO. Far more alike than different. I’m actually amazed how identical the bass is! That shows just how much is the room. Both sound great in the bass, I have no booms, honks or anything, and it is a fast, agile and musical sound, very easy to follow basslines etc.
I just don’t understand enough about REW to know how to dial room effects out, so again if you give detailed instructions I may be able to get something more generally useful.
PS One other thing worth clarifying is the JR149 tweeter level is where I decided I liked it the best! It is actually quite a bit of cut from its midpoint (about an hour and a half on a clock face), but I could back it off further if I wished. They sound right to me, I’ve tried more and less cut. The Spendors sound right too though, their treble balance is definitely gentler, but very nice and really suits a lot of stuff.
ToTo Man
the band not the dog
No Tony, your measurement above is very useful as its from the listening seat and compares the Spendors and JRs under the same conditions. I was just interested in separate left and right channel measurements from the listening seat to rule out the possibility of stereo combing which my mic seems particularly sensitive to (I prefer to average the left and right measurements instead of taking a single stereo measurement). The similarity in bass response between the two models, if genuine, is quite remarkable, as I had my money on the JR149 being tough to match in that department, especially by a speaker that's even more diminutive in size!
mandryka
pfm Member
I was thinking I would get this man to look at them because he seems to know about the speakers and he's close enough for me to just drop them off. I don't want to send them in the post, it adds to the cost and the faff.
If anyone has a better suggestion or knows anything I should know please say, either here or by PM
http://www.retrotechaudio.co.uk/contact-us.html
ToTo Man
the band not the dog
Whereabouts are you? A more cautious first step may be to find some nearby JR149 owners and organise a get together to establish some sort of reference point of how a JR149 is supposed to sound, and then take things from there.
ToTo Man
the band not the dog
I'm 400 miles away unfortunately, but I'm sure there will be a few JR149 owners in the London area willing to help out.