Norgaard, if you are into building the LXs, I'm sure your up on the background of the Linkwitz designs. Please tell me... is the major breakthrough Sigfried developed simply the discover of the OB speaker configuration? Or is there more to it than that? I would REALLY like your, or others take on that.
What are your impressions on the LX-Mini? And more importantly, to the 521? I am dying for impressions.
I am actually considering building these LXCs first just to play with the 6/24 and get impression of what all this LX stuff is about. LXC
LXmini - crossover (ACN) or 6-24XO
Hello members,
if you have a LXmini -loudspeaker, then the LXmini crossover (ACN) was specially developed by Nelson Pass to meet the requirements of this speaker.
This is the reason why the LXmini-crossover has a equalization network on the
pcb and the 6-24XO has not.
Sure you can build a 6-24XO with the same crossover frequency as the LXmini-
crossover, but it will definitively sound different.
Greets
Dirk
Hello members,
if you have a LXmini -loudspeaker, then the LXmini crossover (ACN) was specially developed by Nelson Pass to meet the requirements of this speaker.
This is the reason why the LXmini-crossover has a equalization network on the
pcb and the 6-24XO has not.
Sure you can build a 6-24XO with the same crossover frequency as the LXmini-
crossover, but it will definitively sound different.
Greets
Dirk
I do realize there is a Pass developed specific crossover design for correction of the LX-Mini and 521 that includes additional processing. A LOT of additional processing in the case of the 521 where the solutions can get very expensive. I would actually invest in the 521s if I knew they would sound at least as good as my current mains. But I have my doubts. Thus, I'm approaching the project cautiously.
To Nelson Pass #776
Thank you! It’s a privilege to have you supporting all of us in our quest for diy audio nirvana. Never mind the fact you are the main catalyst to this obsession I have.
Best Regards
Tom
Thank you! It’s a privilege to have you supporting all of us in our quest for diy audio nirvana. Never mind the fact you are the main catalyst to this obsession I have.
Best Regards
Tom
to elwood625 #790
Hello elwood625,
I tested my JFets in my 6-24XO-builds to match from left to right channel (same buffer-cell in the left and right channel). I matched them to below 1%.
The 'lower' JFet in the buffer (schematic) is always the CCS-JFet which controls the current. I would use here the J113 (but there are also other possibilities). With the bias - resistor - value you adjust the current running through your upper JFet. Would have to be adjusted to the 'needs' of your Toshiba JFets.
I would use the Toshiba JFets in the upper part of the buffer.
Have you ever listened to the 6-24XO with the J113s? Well built this baby sounds incredibly good! My J113s (in the kit) have been matched very well ( I rechecked, measured them).
My opinion: I would use the precious Toshiba JFets in a preamp or poweramp - project.
But you can use them also in this active crossover.
Have fun!
Cheers
Dirk
Hello elwood625,
I tested my JFets in my 6-24XO-builds to match from left to right channel (same buffer-cell in the left and right channel). I matched them to below 1%.
The 'lower' JFet in the buffer (schematic) is always the CCS-JFet which controls the current. I would use here the J113 (but there are also other possibilities). With the bias - resistor - value you adjust the current running through your upper JFet. Would have to be adjusted to the 'needs' of your Toshiba JFets.
I would use the Toshiba JFets in the upper part of the buffer.
Have you ever listened to the 6-24XO with the J113s? Well built this baby sounds incredibly good! My J113s (in the kit) have been matched very well ( I rechecked, measured them).
My opinion: I would use the precious Toshiba JFets in a preamp or poweramp - project.
But you can use them also in this active crossover.
Have fun!
Cheers
Dirk
Hi Dirk -
I think I will stick to the J113's, not sure if the expense is worth the slight improvement in THD. I'm building this for a 150 Hz center point, this is where my Lowther PM2A drop like a rock, and have my REL S/3 subwoofer take over.
Since I have these speakers for Zen Mod's Singing Bush VFET (THF-51s) and now my P channel VFET amp, I want a dedicated preamp for these amps and speakers. So I'm building a single ended BA2018 and I'll add the 6-24 crossover inside the same enclosure so the preamp and crossover are hard wired together. Also saves another set of cables.
Thank you Nelson for the warning, with Dirk's suggestion of matching JFET's from Left to Right same buffer - cell, I would only need 6 matched pairs instead of 12 matched.
I think I will stick to the J113's, not sure if the expense is worth the slight improvement in THD. I'm building this for a 150 Hz center point, this is where my Lowther PM2A drop like a rock, and have my REL S/3 subwoofer take over.
Since I have these speakers for Zen Mod's Singing Bush VFET (THF-51s) and now my P channel VFET amp, I want a dedicated preamp for these amps and speakers. So I'm building a single ended BA2018 and I'll add the 6-24 crossover inside the same enclosure so the preamp and crossover are hard wired together. Also saves another set of cables.
Thank you Nelson for the warning, with Dirk's suggestion of matching JFET's from Left to Right same buffer - cell, I would only need 6 matched pairs instead of 12 matched.
Sorry for the late answer, busy times
I am yet to finish the LX521.4's - at long last got the tools I needed for the final stint today.
But the LX Minis are a fast build and I really cannot recommend them enough as a starting point - the LX521 especially if you make everything your self and don't buy them as a complete kit or finished - is a big project.
Linkwitz designs go way beyond just open baffle.... way beyond.
I have tried to incorporate several of the basics around even dispersion on my own OB's, but there are shortcomings which cannot just be shifted away by time-delays etc. on the miniDSP side.
The LX-Mini's spatial resolution, especially in the depth, is in a league of it's own.
However as always, even though these, as the active ATC's I also have, are relatively easy to place in a room to achieve a good result, there is no such thing as speakers being able to work in any room in any position.
In short: Proper placement will be rewarded, also on these.
End note is that I am grateful to Siegfried Linkwitz for these designs - They are surely a gift
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Thanks VERY MUCH for your answer Norgaard. That is extremely helpful. So there is something unique with the design. With the LX521 build, what are you finding "big"? It doesn't seem like the baffle construction would be too bad. The OB sub looks a bit complicated but not that bad. Maybe this answer would become evident if I purchased the plans or actually saw a pair in person. You are definitely making lean more toware taking it on.
Hi Bob,
My take was exactly the same = "not too big a project".
And if based on a kit or staying with the fundamental design I also think it still holds true, even though there is always a bit more to it than meets the eye at first.
With a not insignificant level of OCD and creative adjustments that can be changed quickly.
So for me it spiralled off, but the journey is all part of the fun....(it better be):
I decided to have a go at veneering myself, tweeter plates milled from brass, cross drillled cable channels in the baffles. Different routing in the sub cabinets also. No butt joints, all bevel cut and using 25mm black MDF for the woofers, everything joined with Lamello biscuits - eventually epoxy glued (and I won't use that again). Of course attempting to keep the tolerances <1/10mm. And thats just to mention the main changes.
It is however very critical to keep the acoustic dimensions on the top baffles accurate, nothing regarding the shape and dimensions on these is a coincidence. They don't look like that just for fun and giggles or to cause a stir
I will not claim the end result is any better than standard but I did have fun (and lots of frustrations) on the journey.
I will be running these on the MiniDSP 4x10HD I have - but as on the Mini's I really - while the ASP's are a nice opportunity - ...really would prefer a JFET based Pass filter for the 521's also - along the lines of the 6-24, or using these slightly modifiied / adjusted
I am yet to dig deeper into the required changes - and only one of my two boards is fully assembled
P.S: The LX minis took two afternoons to asssemble, glue dry time is the main time consuming part.
My take was exactly the same = "not too big a project".
And if based on a kit or staying with the fundamental design I also think it still holds true, even though there is always a bit more to it than meets the eye at first.
With a not insignificant level of OCD and creative adjustments that can be changed quickly.
So for me it spiralled off, but the journey is all part of the fun....(it better be):
I decided to have a go at veneering myself, tweeter plates milled from brass, cross drillled cable channels in the baffles. Different routing in the sub cabinets also. No butt joints, all bevel cut and using 25mm black MDF for the woofers, everything joined with Lamello biscuits - eventually epoxy glued (and I won't use that again). Of course attempting to keep the tolerances <1/10mm. And thats just to mention the main changes.
It is however very critical to keep the acoustic dimensions on the top baffles accurate, nothing regarding the shape and dimensions on these is a coincidence. They don't look like that just for fun and giggles or to cause a stir
I will not claim the end result is any better than standard but I did have fun (and lots of frustrations) on the journey.
I will be running these on the MiniDSP 4x10HD I have - but as on the Mini's I really - while the ASP's are a nice opportunity - ...really would prefer a JFET based Pass filter for the 521's also - along the lines of the 6-24, or using these slightly modifiied / adjusted
I am yet to dig deeper into the required changes - and only one of my two boards is fully assembled
P.S: The LX minis took two afternoons to asssemble, glue dry time is the main time consuming part.
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