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Linkwitz LX521.4 - new build and impressions
- Thread starter suttondesign
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wizardofoz
Member
if you are not building a pair of LX521's it really doesn't belong here. you don't get a pair 521's by changing out the parts for something else. at least built as designed then go about your own improvements on a different box and compare.
This just looks like an abomination IMHO...neither are 521's
This just looks like an abomination IMHO...neither are 521's
Strong words. Do others feel this way?
I am both a careful inveterate DIYer and a student respectful of both Linkwitz & John K.s work.
I did build an lx521 with the original top baffle drivers & the 90 deg dual opposed bass box (V-frame) -- albeit with SBA woofers. The V-frame exhibited enough vibration in its panels that it became clear to me why SL felt compelled to build the bridge stand for the upper baffle. I built the W-frame OB bass box to learn for myself the effect on vibration. The reduction in bass panel vibrations was dramatic. Hence my adoption of the W-frame and direct coupling of the top baffle to the bass box.
If you read SL's notes about his choice of bass config (after he'd already modified the Orion with W-frame bass for its last official version), he states...
Bold emphasis mine
I disagree with SL about the amount of vibration from dual opposed W-frame. It really is minimal and the V-frame is far worse. I suspected his desire to keep construction simple & flat-packable were stronger motivations for his decisions.
The use of the different top drivers was directed by my own comparisons of each driver vs SL's original choices, as I already discussed in earlier posts.
Actually, the single biggest mechanical weakness in my execution comes from the 8" driver -- the amount of bass energy that this driver exhibits with the PEQ boost required to counteract OB cancellation causes the entire top baffle to vibrate at higher volume. Despite the 1.2" thickness. It's on my list of planned improvements for the speaker. (Aside: there's one LX521 user who replaced the BB plywood of that panel with 3/4" aluminum, IIRC, and reported it to be the single greatest mod he'd applied.)
No, my build is not a LX521.4 but it is certainly informed & inspired by it. If that makes it unsuitable to mention in this thread, by all means report my misstep to mods & have them dump the offending posts.
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wizardofoz
Member
Ok so you “sort of built the 521 but not quite”…I did build the 521’s (actually the 4th pair completed after SL released his design) and have kept up with upgrades done after his passing to include the new MG lower mid and crossover changes to support it.
I see no need to go messing with other design variations at this time…ymmv of course and if you have the means to try other things that’s fine too.
As for my comment on the looks - I guess every builder with love their own approach, but no offense was intended.
And for the record the baffle thickness is 3/4” not 1.2”. You also don’t mention what crossover you used - asking out of curiosity
Good for you to follow the Linkwitz route closely. Still, given the exchanges I had with SL about both Orion & 521 while he was still alive, I'm pretty sure he'd have been both sympathetic with my path as well as curious about the end results. He was very much a DIYer & never stopped tweaking his published designs.
And yes, you're right, the appearance of my speakers are low priority because they live in my studio/workshop as references. They are not intended for the LR, where the Orions are doing fine duty.
TBH, my original intent was to build both NaO Note II by John K. as well as the LX521. The 2 designs were so close I felt compelled to compare them. At the time I ordered, some components were out of stock at Solen. When I started building, I used the parts I did receive. The dipole AMT was the only component I planned from the start to veer from both sets of plans: it just made more sense than 2 dome tweeters per speaker, an approach I'd already used in the Linkwitz Orions.
I was not pleased with flex of the 18mm BB plywood top baffle. It ran counter to Linkwitz's own efforts to minimize vibration in the driver baffle of the Orion. The better supported NaO Note design seemed superior, but the 521 shape was more visually interesting to me, so I experimented with several variations for improved rigidity -- a 24mm BB and composites of BB+MDF and BB+aerolam+BB. Aerolam is the honeycomb aluminum + thin skin outer panels used for internal walls and floors of passenger plans. The 4x8 sheet of 12mm thick fiberglass skin aerolam was never used surplus from a YVR service company for Alaska Air that I acquired precisely for applications like this. You might know thatB&W Celestion used aluminum skin aerolam for its celebrated SL600 and SL700 monitors.
The 1.2" thick BB+MDF baffles were the 3rd set I tried. They stayed on because I chickened out of using the aerolam composites. Cutting it created dangerous fine aluminum & fiberglass dust & shards that my dust extraction devices at the time didn't handle well.
I still intend to reduce the vibrations in the baffles. A magnet-mounting of the 8" driver, as used in the Orions, is in the works.
I'd love to try the Linkwitz 22MG, but the €290 price for each is sobering. Likely means >CA$1000 to land it here. Maybe if a friend wants an original up-to-date lx521. I haven't seen any tests or measurements of this driver -- do you have any to share? Is it a variation of the 8" MG driver used in the Orion??
I have no doubt the L26RO4Y04 is a more powerful woofer than the SBA SB29WNRX75 I used, but by the time it came back in stock at Solen, the price had jumped to nearly what it is today -- CA$750, or $3000 for 4 -- nearly 3x that of the SBA. I calculated that the primary difference would be max SPL, the Xmax difference of 15mm vs 11mm: 102 dB vs 98 dB at 30Hz. With a pair of drivers per speaker, the theoretical max is 114 dB vs 110 dB. I didn't think I'd miss the extra 4 dB. The last measurement I made of one 521 clone in a vary large room (around 80x40' with 15~20' ceiling) showed flat response at 30 Hz & around 5-6 dB at 25 Hz. This at 95 dB/1m.
My miniDSP 4x10 HD crossovers are LR4 at 120 & 1000 Hz, and LR4 at 3500 Hz. These were derived experimentally, but they are close to both NaO and 521 originals -- tried both sets with endless variations. In all, I spent some 3 years experimenting with upper drivers & crossover/PEQ settings before settling on the current config. I have a new Flex 8 that will replace the 4x10HD soon.
And yes, you're right, the appearance of my speakers are low priority because they live in my studio/workshop as references. They are not intended for the LR, where the Orions are doing fine duty.
TBH, my original intent was to build both NaO Note II by John K. as well as the LX521. The 2 designs were so close I felt compelled to compare them. At the time I ordered, some components were out of stock at Solen. When I started building, I used the parts I did receive. The dipole AMT was the only component I planned from the start to veer from both sets of plans: it just made more sense than 2 dome tweeters per speaker, an approach I'd already used in the Linkwitz Orions.
I was not pleased with flex of the 18mm BB plywood top baffle. It ran counter to Linkwitz's own efforts to minimize vibration in the driver baffle of the Orion. The better supported NaO Note design seemed superior, but the 521 shape was more visually interesting to me, so I experimented with several variations for improved rigidity -- a 24mm BB and composites of BB+MDF and BB+aerolam+BB. Aerolam is the honeycomb aluminum + thin skin outer panels used for internal walls and floors of passenger plans. The 4x8 sheet of 12mm thick fiberglass skin aerolam was never used surplus from a YVR service company for Alaska Air that I acquired precisely for applications like this. You might know that
The 1.2" thick BB+MDF baffles were the 3rd set I tried. They stayed on because I chickened out of using the aerolam composites. Cutting it created dangerous fine aluminum & fiberglass dust & shards that my dust extraction devices at the time didn't handle well.
I still intend to reduce the vibrations in the baffles. A magnet-mounting of the 8" driver, as used in the Orions, is in the works.
I'd love to try the Linkwitz 22MG, but the €290 price for each is sobering. Likely means >CA$1000 to land it here. Maybe if a friend wants an original up-to-date lx521. I haven't seen any tests or measurements of this driver -- do you have any to share? Is it a variation of the 8" MG driver used in the Orion??
I have no doubt the L26RO4Y04 is a more powerful woofer than the SBA SB29WNRX75 I used, but by the time it came back in stock at Solen, the price had jumped to nearly what it is today -- CA$750, or $3000 for 4 -- nearly 3x that of the SBA. I calculated that the primary difference would be max SPL, the Xmax difference of 15mm vs 11mm: 102 dB vs 98 dB at 30Hz. With a pair of drivers per speaker, the theoretical max is 114 dB vs 110 dB. I didn't think I'd miss the extra 4 dB. The last measurement I made of one 521 clone in a vary large room (around 80x40' with 15~20' ceiling) showed flat response at 30 Hz & around 5-6 dB at 25 Hz. This at 95 dB/1m.
My miniDSP 4x10 HD crossovers are LR4 at 120 & 1000 Hz, and LR4 at 3500 Hz. These were derived experimentally, but they are close to both NaO and 521 originals -- tried both sets with endless variations. In all, I spent some 3 years experimenting with upper drivers & crossover/PEQ settings before settling on the current config. I have a new Flex 8 that will replace the 4x10HD soon.
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somebodyelse
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Celestion, not B&W. Also interesting in this context because of the dipole sub and active crossover that could be added to the SL600 to make the SL6000.
Thanks for that. Correction made.
OB subs have been around for some time. Gradient made one in the 70s for use with Quad ESLs.
FYI, pictured with my DIY 521 clones in a previous post is a partial attempt to replicate the Gradient 1.4 -- or rather, AINO Gradient, Juhazi's DIY take on it: https://www.diyaudio.com/community/threads/aino-gradient-a-collaborative-speaker-project.231353/ My trial didn't go far, due, I suspect, to flaws in the 12" PA driver I chose or perhaps because of the success of the 521/NaO project. I reserve the right to revive it in the future.
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Dial back the aggression and snark. Take a break and come back once you aren’t so grumpy.
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I met SL and his wife once and had some email correspondence. He was very friendly and open to ideas, a real gentleman and entuhiastic experimenter-diyer with speakers.
I am surpised how jealous and secretive most of the owners of his speakers are, nothing should be changed or critisized and no measurements shown publicly. I am not a member at OPLUG but I read it sometimes.
Like mikessi I got great inspiration and info from linkwitzlab website and adopted some ideas, but even more from Kreskovsky and Gradient. Very few speakers are totally new concepts and there never will be the ultimate best speaker.
I am surpised how jealous and secretive most of the owners of his speakers are, nothing should be changed or critisized and no measurements shown publicly. I am not a member at OPLUG but I read it sometimes.
Like mikessi I got great inspiration and info from linkwitzlab website and adopted some ideas, but even more from Kreskovsky and Gradient. Very few speakers are totally new concepts and there never will be the ultimate best speaker.
Thank you for the suggestion! So I spent 15min of the rest of my lifetime reading and searching OPLUG LX521 threads back to year 2018 (I started lurking the forum around 2010)
I found two posts with response measurements! Very little discussion about dsp settings either...
It is perfectly ok for me if it stays as a closed community without peer reviews and criticism.
Here is Erin's test of LXMini. He made some changes to dsp settings and measured that too https://www.erinsaudiocorner.com/loudspeakers/linkwitz_lx_mini/
LX521 is very difficult to set up in Klippel NFS as whole, but without sub it should be easy.
I found two posts with response measurements! Very little discussion about dsp settings either...
It is perfectly ok for me if it stays as a closed community without peer reviews and criticism.
Here is Erin's test of LXMini. He made some changes to dsp settings and measured that too https://www.erinsaudiocorner.com/loudspeakers/linkwitz_lx_mini/
LX521 is very difficult to set up in Klippel NFS as whole, but without sub it should be easy.
olieb
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I agree. Considering how much talk there is about this speaker, which is one of a kind, it is more than astonishing that it has not been done already a long time ago. I would love to see Klippel spinorama AND harmonic distortion.
Funny you should mention LXmini, Juha. I made a couple of very nice variants that began as LXminis but morphed -- one with a NEO8, another into an omni with a reflector that houses an upfacing tweeter with reflector. But I won't post any pics of those here -- don't want to start another ruckus! 
Dave Reite, I am now seriously considering about making a complaint of your personal attacks against me. Please stay on topic and I and perhaps many others would be very happy if you could give some information about the issues that are discussed here, that is the role you seem to be playing at OPLUG as "Davey".
The reason why I haven't signed at OPLUG is that I get so much info from the mainpage and I have never seen, heard or done any of SL's designs. I feel that I would be an outsider there, so I let it be.
I have been learning dipoles, measuring and setting up dsp since 2013, project thread of my 4-way dipole speakers is https://www.diyaudio.com/community/threads/aino-gradient-a-collaborative-speaker-project.231353/ and compilation from 2015 s is also at https://www.linkwitzlab.com/AINOgradient Neo83 191215.pdf
The reason why I haven't signed at OPLUG is that I get so much info from the mainpage and I have never seen, heard or done any of SL's designs. I feel that I would be an outsider there, so I let it be.
I have been learning dipoles, measuring and setting up dsp since 2013, project thread of my 4-way dipole speakers is https://www.diyaudio.com/community/threads/aino-gradient-a-collaborative-speaker-project.231353/ and compilation from 2015 s is also at https://www.linkwitzlab.com/AINOgradient Neo83 191215.pdf
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