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Pace, rhythm and timing. What do these terms mean to you with respect to hifi?

Have a gander at this
http://jcgl.orpheusweb.co.uk/temp/barik.png
It illusrates the problem with the graph. I've tried to fit a scale (red) with 2.5 Ohm devisions. As drawn you can see that not all the marked values written on the plot align. Adjust to fit them, and one of the others won't fit. Similarly, the freq sale is oif course log.

Similarly the (green) lines show a full size (full) and a 0.708 line (broken). You can estimate a width from this which is around 10 Hz or so. i.e. Q around 3. But it is hard to know where the base of these lines should start as there will be some common resistance, etc.

So depending on how you decide to choose the scaling and origins you can get various values. But even assuming a Q of 3 at 30Hz we end up with a response time of the order of 100 ms at 30 Hz. Harmonics can dodge this are output before the fundamental movements of the bass can get going.

But we really need better data to make this more than a plausible behaviour. Data needed. As has been the case for decades.
 
Even worse trying to find a measurement of a MK1 or 2 Kan. Linn seem to have gone out of their way to avoid tests.
 
Those measurements are for original 3rd order crossovers.

Those that aren’t active will be likely to be running 4ohm crossovers.

And lots of people obviously run with split B139s and an amplifier per driver.
 
My take is that PR&T is an artifact, and an accident, of the origins of Linn and Naim's early products, and not something that was deliberately designed-in.
 
Would the upwards facing drivers be interpreted as almost reverb? Even direct sound from them is going to be a ms or two late as they are set far back
 
Tony L said:
The thing I don’t know is how LS3/5As would sound on Naim. I run them on valves and they sound truly superb.
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I sometimes run mine with a NAP 140 and that combo sounds great, albeit it sounds less good with a Naim preamp in the mix. I don't think there's a lot wrong with Naim power amps. Their speakers were execrable and their preamps overrated, I think. I haven't really heard any of the more recent post-Olive range though.
 
Yank said:
There are Kan and Sara measurements in the old Hi Fi Choice books. They're pretty grisly.
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I've never heard a Linn speaker I thought sounded anything like actual music, which is probably why I always found Linnies' proselytising hugely unconvincing. Linn should have stuck to electronics, they were actually pretty good at that.
 
Naim power amplifiers have conventional performance except for the output resistance and that won't have much effect on a LS3/5A
 
david ellwood said:
Those measurements are for original 3rd order crossovers.

Those that aren’t active will be likely to be running 4ohm crossovers.

And lots of people obviously run with split B139s and an amplifier per driver.
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However without details we can't tell if/how those suggestions actually change the isbarik pair's *mechanical* resonance behaviour, or how. If you have the relevant measured details, please share them and we can then assess what difference they may make. e.g. we'd need impedance plots, etc.
 
sideshowbob said:
I've never heard a Linn speaker I thought sounded anything like actual music, which is probably why I always found Linnies' proselytising hugely unconvincing. Linn should have stuck to electronics, they were actually pretty good at that.
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I very much liked the classic Linn/Naim/Linn systems. I remember the first time I heard a LP12, Naim 32/Snaps/250 and Isobariks properly setup in a domestic setting and I thought it sounded amazing. That set me off down that whole path in the early ‘80s and about 17 years later I ended up with a very similar system myself. I have however never got on with either brand on its own. Once they went their own separate ways I was out. I still very much like the LP12, many ‘chrome bumper’ era Naim amps and the Linn speakers that completed those systems. I’m in a rather different place now taste-wise, but it was good kit and I’d never knock it. To be bluntly honest I can’t think of any full Linn or full Naim system I’ve personally heard myself that I wouldn’t take a really well setup LP12, Nait (1 or 2) and Kan II nearfield system over, and I’ve heard some very expensive ones! Once that combined synergy or whatever it was went I didn’t seem to get on with the company’s individual visions much at all.
 
Jim Audiomisc said:
Erm. -3dB is x 0.708, not x 0.3. And the vertical scale doesn't seem linear to me. Hard to be sure but the full-width looks more like less than 10Hz than more. My best guess is a Q of around 5. But it could be anything from about 3 up. If you call it 3, that's an envelope tau of the order of 100ms.

See if you have more luck than my at trying to align a linear scale against the handwritten values that have no markers. I find when I try this that the gaps don't show the same scaling.

TBH what we really need is some decent measurements. But the effect I've outlined probably happens. Just that we lack data to clarify the timescale.
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Thanks for the clarification. I misunderstood your earlier message (I did think 70% down seemed strange).

Could they really design something so badly so as to end up with a Q of 5? (Rhetorical question).
Just the damping caused by the DCR (2 in parallel) ought to prevent such a high value.
 
S-Man said:
Thanks for the clarification. I misunderstood your earlier message (I did think 70% down seemed strange).

Could they really design something so badly so as to end up with a Q of 5? (Rhetorical question).
Just the damping caused by the DCR (2 in parallel) ought to prevent such a high value.
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The problem is in part the added mass of trapping the air between the drivers. But of course having two linked drivers means more mass than one. And don't assume they are unique in terms of mechanical Q. Other speakers have peak resonances.

I think I first encountered the isobarik driver pair idea in an ancient HFN issued long before Uncle Ivor appeared on the scene. IIRC A comment then was the high moving mass, potentially giving a high mechanical Q.

Nor does it have to be 'bad' if people *like* the result. One of the points I made is that the behaviour I raised as possible would 'expose' the leading harmonics of something like a bass guitar by delaying the fundamental. The result might then give the 'sound' people report where such instruments become clearer and 'better timed' because people find that leading edge of the pluck clearer. if people prefer it, then for them it isn't 'bad'. Just that their 'timing' point is based on something other than they may have assumed.

Note also that some other speakers may be, mechanically, having similar behaviour. But it may not show in the impedance plot because it is in parallel with something else. e.g. if they'd added a parallel 20 -ish Ohm resistor to the barik then the peak would drop and the apparent Q would look lower. But *mechanically* it might be the same. Hence...

However this is still just a plausible idea as we lack really reliable data. Just that it looks like a potential explanation.
 
Jim Audiomisc said:
Nor does it have to be 'bad' if people *like* the result. One of the points I made is that the behaviour I raised as possible would 'expose' the leading harmonics of something like a bass guitar by delaying the fundamental. The result might then give the 'sound' people report where such instruments become clearer and 'better timed' because people find that leading edge of the pluck clearer. if people prefer it, then for them it isn't 'bad'. Just that their 'timing' point is based on something other than they may have assumed.
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Do you think bass reflex rear porting has the same effect?
 
S-Man said:
Just the damping caused by the DCR (2 in parallel) ought to prevent such a high value.
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I'm unclear about this as well. Impedence measurements normally involve a relatively high resistance being put in series with the speaker and the voltage being read across that. This would mean the Qes component would be mostly absent from this measurement?
Qes is vital in determining Qts - the important bit - of the system in operation.

We don't know how the impedance measurements were actually made in this instance and the whole thing is complicated by the two drive units being closely coupled and in parallel but the principle remains.

If this is the case, and we are mostly only measuring Qms from the impedance graph, then the high Q shouldn't be a problem. In fact, some argue that a high Qms is a good thing.

Additional data: For a stand alone B139, Qms is 4.54 but Qes is about 0.41 giving a Qts of about 0.37. That's free air and box loading increases the the Qms in the system. Amplifier output impedance, series inductors and speaker cable resistances all affect Qes.
 
The basic problem here is that a number of factors affect the resulting Q. As things stand we lack sufficient reliable measurements on the barik to go much further. Hence at present I'd just regard what I outlined as plausible, but in need of better/further measurements/examination. Interesting, though.
 
sideshowbob said:
I've never heard a Linn speaker I thought sounded anything like actual music, which is probably why I always found Linnies' proselytising hugely unconvincing. Linn should have stuck to electronics, they were actually pretty good at that.
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Linn Kaber (passive) is a pretty good speaker if you steer well away from Linn / Naim electronics. We successfully ran them with a Densen BEAT B100 in a system that proved very popular with those that heard it.

Can't remember who designed them in that era, but they knew what they were doing with Kabers, and the Helix. The Keilidh was a mess though, far too warm and and a bit lumpen.
 
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