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Linkwitz LX521.4 - new build and impressions

mamsterla

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Hi all,

One of my COVID projects was to build the Linkwitz LX521.4 to replace my first LXmini. I finished them last week and hooked them up to Nord-built Hypex 4-channel amps and a MiniDSP 4x10HD. And Yes, I know these things are ugly. I had put off building them for some time for several reasons: (1) cost; (2) uncertainty about whether they would be too visually obtrusive; and (3) ugly. But COVID made me say, What the heck, just do something already. So I did. I don't think building them out of pretty wood makes them appreciably nicer looking, so I just ordered the Madisound Baltic-birch kit.

I've had the weekend to listen, and I just want to report that these are, hands-down, my favorite speakers ever, including the Dutch & Dutch 8C, which I sell as a dealer and think are awesome. Of course, by the time you've built the LX521.4 and obtained the 8- or 10-channel amp(s), 4x10HD, and decent cabling (copper speaker wire, a bunch of XLR's, 6 or 8 male and female Neutriks, etc.), you'll have spent about $6,000, give or take, so it's not like you're getting off cheap, but what a payoff.

If anyone knows why, I found I couldn't use unbalanced RCA connections from MiniDSP 4x10HD to the Nord amps without ungodly ground loop noise. But once I switched over to balanced connectors using the Phoenix pigtails supplied with the MiniDSP, the noise went away entirely. I've got two separate Nord amps, one a year old, one new, and the older one had no problems running unbalanced to my prior LXmini. I can't figure how this new build created a ground loop.

Congrats on the build. I went with the Hairball Audio analog ASP.4 crossover and ATI AT528NC amps. My build is painted and uses a veneer on the bridge - learned a lot and would do it differently if I had a chance - trying to get a piano black is really hard with the paint and sprayer I had at my disposal. I've had it for about 2 years and also really enjoy mine. I pair it with dual Rythmik F15HD subs and miniDSP 4x2HD handling them. Crossover is at 60Hz and the bass is just so good with that system - multiple subs have given an almost flat in-room response at my seating position.

I know I have a huge reflective screen behind the speakers - I just don't have a way to change the room at the moment. I am using Anthem's ARC to help correct some of the problems.

LX521_front.jpg

LX521_back.jpg

LX521_pair.jpg
 
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pokerbarlo

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Can I use 6 channels of 3 ncore 250 plus 4 channels of 2 ncore 500 for the 4 sub drivers for this what would be most optimal? With minidsip 2x10
 

phoenixdogfan

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Is there a way to build the crossover and eq filters on a pc based crossover system like Ekio and then use a high quality 8 channel DAC like the Octo Dac 8 Pro? Seems to me using something like 4 Purifi Eigentact amps is going to waste if you're also using the miniDSP 4 X 10.
 

kjb

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Sorry to hijack the thread, but I figured this would be a good place to ask. I'm thinking of building a pair of these as a sort of follow up project to a Linkwitz Pluto-inspired 3-way speaker I recently attempted.

Would it be okay to construct the LX521 baffles out of transparent acrylic, polycarbonate or even glass?
As far as I can tell, nobody's done that. I think it would improve the appearance of the speaker tremendously, at least for those of us who prefer a more conventional design.

Take a look at this thread on oplug.
https://oplug-support.org/viewtopic.php?f=28&t=2649&start=25
 

pokerbarlo

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This is actually a good question what is the best way to build this with which crossover and suggested DACS Okto Dac 8 pro is out of stock.

Is there a way to build the crossover and eq filters on a pc based crossover system like Ekio and then use a high quality 8 channel DAC like the Octo Dac 8 Pro? Seems to me using something like 4 Purifi Eigentact amps is going to waste if you're also using the miniDSP 4 X 10.
 

Burning Sounds

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You can build the x-over/eq in JRiver or Roon's DSP. I've done both and they work fine and they both sounded the same and measured the same regarding transfer function. The problem with JRiver's DSP is that there is no visual representation of what you have built and you will need to adjust the shelving filters' Q - https://wiki.jriver.com/index.php/Parametric_Equalizer#Q_or_S

In Roon at least you can see what you have built - but of course there is a big difference in cost between JRiver and Roon.

Some people have concerns about running x-overs/eq in software as a PC crash or freeze has the potential to send all frequencies to the tweeter. In more than 5 years of running LX521 x-overs/eq in software - primarily JRiver (I only did it in Roon during a 90-day trial - I didn't subscribe to it in the end) I have never had an issue with this. On the very rare occasion when JRiver has frozen or crashed there were never any problems. I don't worry about it.
 

phoenixdogfan

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This is actually a good question what is the best way to build this with which crossover and suggested DACS Okto Dac 8 pro is out of stock.
They will eventually restock. I have one on order, and a two channel Purifi. Adding three more Purifis and buying the makings of an LX 521 seems feasible to me if I move somewhere with a bigger listening room.
 

JimB

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An interesting development is that Dr Frank Brenner in Germany has a new magnesium lower mid driver for the LX521 - https://linkwitz.store/product/linkwitz-22mg/

It's considerably more expensive than the original polypropylene driver, but is a direct replacement requiring a few eq tweaks.
Nice. I've wondered about the potential of the Purifi drivers for midrange in an Orion three-way.
 

Pultzar

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1619501515599.png


I painted my panels black and wrapped everything else in black velvet. They look pretty fantastic. The room they are in is also black velvet. Gives new meaning to speakers disappearing :) They also have a base so I can move them around as necessary.

Dipole bass is nice but it is not a magic bullet. Dirac helps a lot. I am crossing over to a pair of subs built with Eminence NSW6021 drivers. For music I don't think that subs are necessary but for home theater they are valuable.
 

Colonel7

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View attachment 126564

I painted my panels black and wrapped everything else in black velvet. They look pretty fantastic. The room they are in is also black velvet. Gives new meaning to speakers disappearing :) They also have a base so I can move them around as necessary.

Dipole bass is nice but it is not a magic bullet. Dirac helps a lot. I am crossing over to a pair of subs built with Eminence NSW6021 drivers. For music I don't think that subs are necessary but for home theater they are valuable.
That is a great design. Best looking ones I've seen by far. I daresay the back even looks elegant. Most of the other pics in other builds look like they should be in a log cabin. Nice job!
 

Colonel7

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View attachment 126564

I painted my panels black and wrapped everything else in black velvet. They look pretty fantastic. The room they are in is also black velvet. Gives new meaning to speakers disappearing :) They also have a base so I can move them around as necessary.

Dipole bass is nice but it is not a magic bullet. Dirac helps a lot. I am crossing over to a pair of subs built with Eminence NSW6021 drivers. For music I don't think that subs are necessary but for home theater they are valuable.
Do you know if the velvet affects the sound in any way?
 

pokerbarlo

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You can build the x-over/eq in JRiver or Roon's DSP. I've done both and they work fine and they both sounded the same and measured the same regarding transfer function. The problem with JRiver's DSP is that there is no visual representation of what you have built and you will need to adjust the shelving filters' Q - https://wiki.jriver.com/index.php/Parametric_Equalizer#Q_or_S

In Roon at least you can see what you have built - but of course there is a big difference in cost between JRiver and Roon.

Some people have concerns about running x-overs/eq in software as a PC crash or freeze has the potential to send all frequencies to the tweeter. In more than 5 years of running LX521 x-overs/eq in software - primarily JRiver (I only did it in Roon during a 90-day trial - I didn't subscribe to it in the end) I have never had an issue with this. On the very rare occasion when JRiver has frozen or crashed there were never any problems. I don't worry about it.
View attachment 126564

I painted my panels black and wrapped everything else in black velvet. They look pretty fantastic. The room they are in is also black velvet. Gives new meaning to speakers disappearing :) They also have a base so I can move them around as necessary.

Dipole bass is nice but it is not a magic bullet. Dirac helps a lot. I am crossing over to a pair of subs built with Eminence NSW6021 drivers. For music I don't think that subs are necessary but for home theater they are valuable.

Was planing on using these as my LCR for home theater as well what is your whole setup? What did you match for satelittes and atmos? have any pictures?
 

Pultzar

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Was planing on using these as my LCR for home theater as well what is your whole setup? What did you match for satelittes and atmos? have any pictures?

I don't have any pictures now but might take some. It's tricky to represent because the room is all black velvet over custom made diffusers, absorbers, etc.

So the LX521 are left and right with a phantom center. I'm using Pluto's for the surrounds. . I haven't completed Atmos but planning on some coax speakers for that. I'm also considering replacing the Plutos with the JBL CBT speakers that were recently reviewed here.

I have considered them for LCR behind a transparent screen, but I'm concerned about the listening distance.

Just when my theater got more or less finished, my wife and I purchased property and we are building a new home which will include a much larger theater space. I might retire the LX521 from theater duty and instead pull them out for music listening. They sound excellent but I want speakers behind the screen so something that doesn't need to be out from the wall would be ideal.
 

Pultzar

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Also for people considering subs for HT use, don't waste your time with Thor like I did. Go for something with much higher output capabilities.
 
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