Linn Nexus LS250

ticktock

Member
2006-12-21 9:35 am
Please can i have your opinion on the said speaker the sound is not that good to my ears.
The (stock) Nexus' sound always has been poor.


Do you guys think if i recap the crossover will be beneficial or i'm only going to waste my money.
Definitely a waste of money. You'll need a better designed crossover instead.
Increased component quality cannot substitute a proper crossover layout. ;)


Still an interesting story about how Ivor T. likes speakers to be designed. :tilt:
 
The (stock) Nexus' sound always has been poor.

If only you can share your mods ;).

Definitely a waste of money. You'll need a better designed crossover instead.
Increased component quality cannot substitute a proper crossover layout. ;)

I think so it's in crossover design, because my amp is working effortlessly with the other speakers but in Lexus I need to crank up the volume to produce ample bass. I wanted to try with a different crossover but I don't know where to search for the right one? you got one? :D
 
I have a pair of Nexus' too.

I find the bass adequate - I'm not a bass-hungry listener, but I do find the treble tiring.

I was wondering whether there is anything I can do to re-house them into a better cabinet...

I find them musical enough, but top end is 'brittle'.
I can't find much to dislike about this speaker, an 8" paper bass and 1" tweeter on 4th order acoustic crossover, I'd suppose. Certainly, changing the baffle won't help tweeter response much. Though, I don't much like soft-domes at all. They have a poor signal to noise ratio at the top end IMO.

I feel like I'm saying the same thing over and over, and just not getting through.

To reduce tweeter level, you adjust attenuation. To roll off the top end, you add a Zobel:
Impedance Equalization (L-Pad) Circuit Designer / Calculator

You really need to draw up the crossover schematic to change things predictably. I guess you're not going to want to do that either.

One of my similar efforts below. A mylar tweeter. Wired negative polarity on 3kHz crossover.
 

Attachments

  • Lynn Nexus LS250.JPG
    Lynn Nexus LS250.JPG
    30 KB · Views: 279
  • Visaton Build.jpg
    Visaton Build.jpg
    70.3 KB · Views: 288
  • 8inch bass plus tweeter 3kHz XO.PNG
    8inch bass plus tweeter 3kHz XO.PNG
    8.7 KB · Views: 278
I used to be the friendliest, most constructive poster at this forum. I think some of the rest of the members here have rubbed off on me, these days. Sorry. :eek:

19/20 threads at this forum go nowhere. I happen to be rather experienced at 8" bass plus 1" tweeter. If you're willing to put in some work, so am I.

I'd dump the soft dome in favour of a metal dome in this case. SEAS TBFC/G

It'll need a Zobel to sound good at the top end. 6R and 1uF is about right for Le 0.05mH and 4.8 ohms:
H1212-06 27TBFC/G

You might then need to adjust attenuation. That needs a schematic to be precise. You see, without that, we are blind men without a stick. :D
 
The tweeter crossover may have a zobel already. Maybe 1.5uF and 6 ohms.

The circuit is very hard work to decipher. Looks like 4th order on both sections. That's a positive polarity on both drivers solution usually. But I'd want to sim it.

Bass will go roughly coil, cap, coil, cap with a resistor thrown in with one of the caps.

Tweeter will go cap, coil, cap, coil then a zobel by the look of it. That's quite easy to attenuate, you just put a resistor at the input.

If you look at the back of the PCB, you can see the wiring and polarity on the speaker biwireable input. I usually flip it 180 degrees in paint to relate it to the view from the other side.

The left hand side in the vertical layout up from the input plugs is the bass section. Bigger values. Resistor and capacitor values are easy enough, without an inductance multimeter we'll just have to guess coil values.
 

Attachments

  • Lynn Nexus LS250 circuit tracks.JPG
    Lynn Nexus LS250 circuit tracks.JPG
    22.7 KB · Views: 118
  • Lynn Nexus LS250 Components.jpg
    Lynn Nexus LS250 Components.jpg
    106.8 KB · Views: 257
  • Lynn Nexus LS250 Crossover.JPG
    Lynn Nexus LS250 Crossover.JPG
    67.8 KB · Views: 253
  • Lynn Nexus LS250 Crossover another view.jpg
    Lynn Nexus LS250 Crossover another view.jpg
    172.6 KB · Views: 122
Last edited:
I think you did well to decipher that one, Junie! Looks like the positive input is actually the earth plane on the PCB.

It still doesn't make sense on tweeter Zobel placement, but you end up with a sixth order acoustic bass and 4th order acoustic tweeter for sure. Which is a complete mess on phase. It just misbehaves above crossover point because the bass rolls off too much.

This is potentially a lovely speaker. The crossover guy just didn't really get the right idea at the start. No wonder he spent 6 months fiddling with it. The filter should have been strangled at birth.

LR4 is one good way to do this sort of thing. 24dB/octave acoustic filters. It's usually a positive polarity solution, but with an 8" bass the time alignment is about half a wavelength (5cm) off at 3kHz, so you wire negative polarity.

Big basses have big mechanical rolloff to start with so you only need 2nd order electrical on them. I came up with a nice circuit. Phase alignment to die for. Detailed sound. Won't be overly bassy, as it goes. That's my taste, and you could change that.
 

Attachments

  • Linn Nexus LS250.JPG
    Linn Nexus LS250.JPG
    30 KB · Views: 139
  • Linn Nexus Improved 2nd and 4th order filters.PNG
    Linn Nexus Improved 2nd and 4th order filters.PNG
    8 KB · Views: 154
  • Linn Nexus Improved FR.PNG
    Linn Nexus Improved FR.PNG
    17.2 KB · Views: 155
  • Linn Nexus Improved Phase.PNG
    Linn Nexus Improved Phase.PNG
    18.2 KB · Views: 109

Attachments

  • DSCF2866.jpg
    DSCF2866.jpg
    813 KB · Views: 40
  • DSCF2867.jpg
    DSCF2867.jpg
    958.6 KB · Views: 44
  • DSCF2868.jpg
    DSCF2868.jpg
    981 KB · Views: 43
  • DSCF2869.jpg
    DSCF2869.jpg
    992.8 KB · Views: 34
  • DSCF2870.jpg
    DSCF2870.jpg
    983.1 KB · Views: 35
  • DSCF2871.jpg
    DSCF2871.jpg
    823.7 KB · Views: 28
  • DSCF2872.jpg
    DSCF2872.jpg
    861.9 KB · Views: 28
  • DSCF2873.jpg
    DSCF2873.jpg
    870.4 KB · Views: 28
  • DSCF2858.jpg
    DSCF2858.jpg
    995.6 KB · Views: 38
  • DSCF2853.jpg
    DSCF2853.jpg
    1,018.4 KB · Views: 39
Last edited:

NLT

Member
2021-12-30 8:27 am
I needed to jump in on this...

I have the version of the LS250 that Maniac has and it is crazy to me what I hear from other forum members. The LS250 is a 'fantastic' speaker and it was designed by a guy who is... literally a doctor of physics. He had limitations placed on him by the market and by Linn. The baffle is plastic and I think thats probably the worst part. That being said, they sound better than other Linn speaker from that time period. Voiced drastically better than a Helix or a Keilidh. To me, they are a speaker for people who care about the natural reproduction of instruments. There are other speakers who have greater coherence, but on the LS250 a violin or an acoustic guitar sounds like exactly that.

As it pertains to the tweeter. The OW1 is probably not the right replacement for this. The original tweeter is an exact mechanical match to an OWII and the subtleties of that sensitivity change are not that subtle. The OW1 rolls off at 18k instead of the full range. While preferred by a lot of people, you would need a different crossover. I prefer the OWII because I think it resolves cymbals better.

If I were going to re-design this speaker I would (and I don't really know that much):
1. put it in a better box but not a box with no resonance at all
2. use a 3rd order filter on an OWII
3. use a 2nd order on the Woofer
 
I needed to jump in on this...

I have the version of the LS250 that Maniac has and it is crazy to me what I hear from other forum members.
I have since moved onto McIntosh SL-6 with solidified ferrofluid in the tweeters... Which i put up with for a few months, bought a 6 pack of 0.1ml ferrofluid to fix it. Then proceed to sit on it for a few months....

Then finally went ahead and fixed it. That was a major pain. I more our less traded the LS250 for SL-6 (bought and sold them for equivalent price), might be interesting to see where i end up with in a couple of years... ;)