So the HP out of the miniDSP is phase-reversed? This will confuse many week-enders like me....
There's a difference between phase and polarity.
The woofer and tweeter ARE in phase at the crossover frequency even though they're wired with reverse polarity relative to each other. The HP output of the miniDSP is NOT phase-reversed in this case since SL has chosen to implement the required polarity change with driver wiring vice toggling a setting of the miniDSP. If week-enders follow the directions in the LXmini construction manual they will have no problem. This particular system uses a frequency-independent delay (vice an all-pass filter) on the tweeter to effectively time-align the drivers, but it's still not a linear-phase design.
Cheers,
Dave.
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Member
Joined 2006
Yeah, I'm not going to take the bait on that one.
My response in post #12 works for this query too. My subjective evaluations regarding power amplifiers are meaningless to anyone else......as are theirs to me.
Use whatever power amplifiers you want, as long as their characteristics don't skew the response of the drivers/system......or if they do, that you understand that fact.
And that goes for DSP boxes (and other equipment) too. Use whatever you want.....as long as you understand what you're doing.
Cheers,
Dave.
Member
Joined 2006
well, a lot of us already have $$s in there and may now be looking for compromizes
. SL seems to have broken the mold on the acoustic design. if he is short of challenges now, he could try for something with higher sensitivity to make papa's amps run at least the critical mid section. should I add: "please"... maybe leave the bass to distributed subs, and reduce cone travel requirements in the firtst couple of hundred hertz of low mid since he just proved a true dipole could start higher, and.... well, the more (modular) choices he gives us the better.
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well, a lot of us already have $$s in there and may now be looking for compromizes
You want SL to redesign/compromise his system with different drivers and a separate woofer system so that specialized low-power/low-gain/high-z amplifiers could be used??
If you already have that type of amp (that you want to use) it likely steers you to a particular type of speaker system, yes?
Cheers,
Dave.
Instead, SL might just stimulate some new amplifier designs.
Uh-oh! (Checks bank balance)
One thing I find interesting about this speaker is that the mid-tweeter is still a 4" so it is more similar to a FAST than a conventional multi way speaker with a conventional tweeter. I can't but wonder if there is something missing in the 10 khz + dispersion. Or if it doesn't matter and using a tweeter is just overkill.
Especially as most tweeters are domes which are hard to integrate without large waveguides, using say a 2" - 3" mid-tweeter full range driver would be much easier to integrate. If we want symmetric response we can just use two with one pointing backwards.
Especially as most tweeters are domes which are hard to integrate without large waveguides, using say a 2" - 3" mid-tweeter full range driver would be much easier to integrate. If we want symmetric response we can just use two with one pointing backwards.
Many, many, if not most people on diyAudio build amps, so we have an "Amp Build Up" problem. And most of the amps built are Pass designs I think. The Linkwitz multi-amp systems might allow us to use all the amps and amp parts we have laying around.
and while the parts aren't super cheap, due to the massive power supplies and heatsinks, they are much much cheaper to build than to buy. It seems that the complementary designs would work better for the output needed on peaks and such.From talking to people at Burning Amp I get the impression that lots of people have a secret wish that they could have Pass amps on at least some of the drivers in SL designs, even though it doesn't seem that straightforward.
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+1 ( I have LX521 kit in a box (without the bass section though), but am still working on my own OB to drive with papa amps. I am however making subs for a distributed bass to add the LX top to it later (and possibly embarass my OB in the process?
). I only know that if I knew the miniLX was coming I would have waited since that would have earned me some BIG points with my wife (unlike my OB which..., well you can guess the reaction: 
) oh oh. hope at least PSs can be carried over? I was gonna bring myself in winter time to build some P3As and such but maybe I should wait?
It's pretty clear that the top end will get by with 10 watts or so, but even
with level adjustment on the dsp needs 20+ dB of gain.
Existing power supplies will support that, and balanced outputs would give
the voltage swing for the 80+ watts required for the bottom, so you might
easily re-purpose those transformers and caps.
with level adjustment on the dsp needs 20+ dB of gain.
Existing power supplies will support that, and balanced outputs would give
the voltage swing for the 80+ watts required for the bottom, so you might
easily re-purpose those transformers and caps.
well, a balanced alephP (have those parts too) could drive a balanced F4 with 20dB gain? (Variac is right; this could be about saving all the forgotten parts). I am only so not looking forward to more 
.
Papa, I new only good things could come from the legends sipping wine at the Sea Pine Cottage (yes, yes, the little birdie told me).
The challenge is on you (us) to get an audible improvement though; because if it is all in the acoustics and this is IT, I will have to look for another hobby.
. Papa, I new only good things could come from the legends sipping wine at the Sea Pine Cottage (yes, yes, the little birdie told me
).The challenge is on you (us) to get an audible improvement though; because if it is all in the acoustics and this is IT, I will have to look for another hobby.
Surely we need to have competent people to 'peer review' a design, not just drones of cheerleaders. The work of JohnK, for example... how many years in advance with symetrical tweeter, narrowing baffle panel, etc ? Be objective to the task!
It had been proposed that uniform directivity is desired, hence the evolution towards LX521, Nao Note, etc. But now with LXMini we have monopole -> cardioid -> dipole -> monopole towards higher frequency. This is the complete opposite of LX521. Surely this needs investigation. The reflected sound is no longer replicas of direct soundwaves.
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I have some speakers which are well regarded examples of constant directivity (Gedlee Summas) and I also have some DIY speakers that are cardioid in the mid and CD in the highs.
I find that the cardioid definitely adds something. It's similar to the effect that you get with dipole speakers, that big spaciousness.
If I could integrate a second tweeter firing backwards, to make it cardioid in the mids *and* the highs I would.
Of course this is one of those things that will depend on a person's preferences; the additional energy radiated backwards might not be everyone's cup of tea.
I've also tried the Summas as a mono bipole (Summas back-to-back) and the sound of that was excellent also, I definitely considered it an improvement.
"Preference", and the room. I've been a dipole advocate since my first Maggies over 35 years ago, but in my listening room never with rear tweeters. I put absorbers behind the ribbons in my MG-III, and reverted to "front only" after trying the rear tweeter mods with my ORION. And my LX clone is definitely a "no rear tweeter" project. All because of my "front wall" . . . (although that is mitigated somewhat now by my failing HF hearing).
All speakers are influenced by the room . . . none sound the same outdoors (no room) as they do in a bedroom or bathroom. "Constant directivity" speakers may fare better in that regard, but they are not immune, and the "spaciousness" offered by dipoles and omnis comes at the risk of the intrusion of response irregularities from the room. There are always tradeoffs.
I have not yet heard the LXmini, and apart from curiosity don't have any reason to. I recognize the compromises, and the intent of the compromises, and fully expect that they sound just fine used as intended in appropriate listening rooms (which is probably most). I can also with some confidence predict that, because of "geometry" (particularly door and window location), they wouldn't work well in mine (which is, for the same reasons, ideally suited to dipoles). They are, nevertheless, and interesting exercise, no doubt "better" than PLUTO in the midrange, and yet another example of SL's ability to both innovate and to pick his compromises well (which itself obviously comes from his understanding, grown from long experience, of room/speaker interaction).
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