Extreme Open Baffle Active Speaker inspired by Linkwitz LX521

[al2002]

Photos here:

LX521 Photo Gallery

I would love to see / hear the LX 521 in Chandigarh, but it's a little too far north for me. I'm an expat living in central Mumbai. No offense to Mumbai, but I do miss my home town of Honolulu! I have no problem buying the plans. It's the ASP or DSP that I don't want to buy. But I'll reconsider it. Thanks, John

 

[MITsound]

Greetings. I don't mean to hijack this thread, but am in the midst of redoing my dipole system.
Right now, I'm going from no baffle to minimal baffle for a Neo 3, Neo 8, Neo 10 vertical array, actively crossed above a Dayton Audio RSS 265 HF-4 for midbass.
This seems fine for voice on up, but my question is regarding the redeployment of already owned bass drivers.
For better stereo and overall better bass, would I be better off using the two 18" subwoofers at left and right with a stereo amp, with my ready owned SPA 1000 driving a centre fill push pull with the two 15" Trace Elliot/ Celestions in parallel?
Or parallel a Celestion with the 18" PP183 , for two left and right panels?
Also, does it matter to have these in stereo at a 100 hertz cutoff, or would they be better as mono distributed bass dipoles in 3 or 4 locations?
I've been having trouble with placement that'll provide good bass, as well as mid and treble playback when all drivers are on a left and right baffle.
Sorry if this is the wrong thread for this, there doesn't seem to be much for distributed bass threads for dipoles.
Thanks.

 

[erez1012]

The circuit reference the original machine design, symmetrical FET input stage for the whole structure, the output coupler for the German elixir WIMA capacitors, small silver mica capacitors imported pipe selection of imported and precision pairing. Designed to separate left and right channels, each of two boards
Test data show that the distortion of the circuit is very small and the gain of each band is relatively average. Gain of the entire circuit is approximately 3.2 times.



• Input stage : 2.5-3MA
• Voltage amplifier stage : 20-25 MA
john curl
diyAudio Member



Join Date: Jul 2003
Location: berkeley ca Higher Idss, over 15 ma is best.


I use K170/J74 BL class with idss 9.2~9.4ma

Hi gk7

I use the exact values of the attached schematic but changed R16/R18 to 150 Ohm.
I did build the phono stage but I have problem with the offset. I got 250mv at the output. Attached is the phono schematic I use.
 
hi Gerhard
i want to build active crossover 2 way to my open baffle speaker according to LR.
what type of OP amplifier do you use in the filter?
capacitors?
thank

 

[mikessi]

Hopefully this thread is not completely dead!?

Joachim Gerhard -- Why did you spring-mount the Heil tweeters? Did you compare the sound to firm mounting (either in this project or elsewhere)? And are your speakers now "finished" -- I know as a DIYer, that they're never finished, but in relatively stable state? And how do you like them... compared to anything?

I'm building an LX521/NaO Note II RS blend w/ Aurum Cantus AST2560 Heil tweeters, with top baffle made of aerolam (aircraft aluminum honeycomb panels) laminated between thin layers of Baltic Birch.

Hence: Really curious about the shock mounting of your tweets....

 

[UlrikSan]

Hopefully this thread is not completely dead!?

Joachim Gerhard -- Why did you spring-mount the Heil tweeters? Did you compare the sound to firm mounting (either in this project or elsewhere)? And are your speakers now "finished" -- I know as a DIYer, that they're never finished, but in relatively stable state? And how do you like them... compared to anything?

I'm building an LX521/NaO Note II RS blend w/ Aurum Cantus AST2560 Heil tweeters, with top baffle made of aerolam (aircraft aluminum honeycomb panels) laminated between thin layers of Baltic Birch.

Hence: Really curious about the shock mounting of your tweets....

Mike, I'm curious. Did you build the speaker?

 

[Joachim Gerhard]

No, i did not compare to fixed mount in this build. From older implementations i know that the tweeter will sound more detailed and 3-dimensional that way.

 

[Telstar]

I admit defeat . I am a new member since yesterday , but have been actively lurking in here and conversing with Rudolf over email . Just read my introduction post . I really was under the impression that I would be the first to build a dipole using the Mundorf AMT 25d1.1 but alas , you beat me to it .
Anyway , my project is not finished yet but I already have some pics of the H-frame , minimal baffle for mids and tweets with drivers mounted (midranges are Wavecor WAF138 )
...
The baffle form is as narrow as possible for each driver to optimise sound dispersion as high in the frequency range as needed for the Xover point . Xovers will be around 250 and 1750 Hz

I thought Joachim was the only one who used them! This is the only thread I found. Are you still using these dipoles?
Can you describe more how does it merge with mids and other problematics (vertical directivity for instance, which is an issue on the Dayton)?

 

[mikessi]

Mike, I'm curious. Did you build the speaker?

Super late reply. Wasn't getting notices of posts here for a while.

No, I did not finish. Someone warned me that "normal" aluminum honeycomb panels like those used as floors on commercial aircraft (which is what I have) are too resonant to use in audio products. Rudimentary testing seemed to confirm this so my enthusiasm for the project waned. The Celestion SL600 and SL700 used aerolam and were successful, but I could not find out whether the panels were modified in any significant way to damp resonances.

In any case, I got embroiled in a major house move, then a complete house rebuild which took well over a year, and my workshop remains in chaos after all this. In a few more months, I will experiment further with aerolam.

 

[dtaylo3]

I see that Stereophile's website today has an interview with S. Linkwits and some video of his LX521.