thanks Dewardh, I think there will be another LX521 on the go soon! 
The bass separation is also a great thing, we can then place the subs close to the side wall, hiding them as flower or art stands. Or, now the tweeter is not the achilles heel anymore, make a tower of them to reach higher SPL and run them fullrange without the 30hz cut.
The bass separation is also a great thing, we can then place the subs close to the side wall, hiding them as flower or art stands. Or, now the tweeter is not the achilles heel anymore, make a tower of them to reach higher SPL and run them fullrange without the 30hz cut.
that's exactly the issue I have, low ceiling only 2.3m high. I guess apart from a line array there is no other solution than acoustic treatment. Does it have to be broadband? Can't loose more than 10cm..
Keep in mind that excursion goes waaaaay up on an open baffle compared to in a box.
Is that electrical 2nd order ( crossover only ) or driver plus crossover 2nd order ( acoustic)?
"Why" is not only complicated but also beyond what psychoacoustics can yet explain. More research is desperately needed.
I don't know what you are doing that is different from what SL is doing, but "excessive excursion" is simply not an issue with the LX521. The cones on the drivers in LX521 are well behaved far enough out from crossover that the benefit of higher out-of-band suppression (necessary, for example, with the W22) just isn't there. With many drivers I'd expect higher order to sound better for that reason (stop-band suppression) alone. Imaging is possibly helped by the lower phase shift of the lower order filter . . . at very least it's one less confounding variable to worry about. What we perceive, even how we perceive, in the critical midband is still an open area of study. The motors and suspension of both drivers are obviously quite good, and seem well matched and balanced for the application. There may be some room for improvement, but I'd expect it to be modest.
Initial shipment of the custom "SL" drivers is promised RSN, although until there is sufficient supply they may be reserved for licensed builders. Once they are available you might want to get a set . . . the baffle dimensions can be easily figured from a photograph (especially if you think like an engineer
I see another cross post. Do't you get tired of cut and past? For those who care, here is a link to my response over at the PE board.
LX521 revisited
hahaha! Omg......a speaker build off!
Sounds like a great new reality show
We can get 10 designers together living in a house...at each others throats.
Crying and hugging, each with their own life's sob stories.
....I grew up hard man, I couldn't afford a a router until I was 18......
and it was a skill router at that!
Sounds like a great new reality show
We can get 10 designers together living in a house...at each others throats.
Crying and hugging, each with their own life's sob stories.
....I grew up hard man, I couldn't afford a a router until I was 18......
and it was a skill router at that!
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2nd order electrical. I've configured the miniDSP for 1st , 2nd and 4th order electrical couplers as well as a 4th order acoustic coupler. All for can be loaded into the miniDSP 2x8 simultaneously and switched on the fly. Make a very interesting comparison of the differences.
And again, when I speak of excessive excursion, I am not speaker of over excursion, just "more than required". Here is a plot of the predicted excursion of the SS Discovery 10F in my design with the various coupler crossovers at a level 22 Vrms, (60w into 8 ohms):
An externally hosted image should be here but it was not working when we last tested it.
Clearly with Xmax of the 10F at 2.6mm there isn't a problem. But form my point of view there has to be a clear advantage somewhere to justify the 1st order coupler. I certainly can not find it in the acoustics. But with a passive coupler I guess you could argue for simplicity. I don't know. Every thing I have done suggest that a 2nd or higher order coupler is superior.
Thanks for the graph John, higher excursion translates to higher distorsion, but maybe we need to read again SL own description:
With two well behaved and capable midrange drivers of different size, but covering nearly the same frequency range, it became feasible to build a very wide bandwidth, 120 Hz to 7 kHz, dipole midrange bandpass filter and keep group delay variation low in its passband by using a 1st order crossover filter around 1 kHz. Group delay variation relates to envelope distortion, which in a 4-way design can be kept lower in the critical midrange than for a 3-way.
Maybe interesting to cross read with the other thread about Greisinger's last paper, phase coherence and such..
Don't you get tired of spaming your problems with your design into all the LX521 threads you can find?
It's an open board and comparison and contrast of designes can only lead to consideration of possible improvement on both ends. Are you so oposed to that? After all, you posed the question, "I don't know what you are doing....". I just answered it.
Thanks for the graph John, higher excursion translates to higher distorsion, but maybe we need to read again SL own description:
With two well behaved and capable midrange drivers of different size, but covering nearly the same frequency range, it became feasible to build a very wide bandwidth, 120 Hz to 7 kHz, dipole midrange bandpass filter and keep group delay variation low in its passband by using a 1st order crossover filter around 1 kHz. Group delay variation relates to envelope distortion, which in a 4-way design can be kept lower in the critical midrange than for a 3-way.
Maybe interesting to cross read with the other thread about Greisinger's last paper, phase coherence and such..
That is indeed a seemingly convincing argument for using a 1st order approach, until you look at the actually GD for different order couplers and the specific 1st order alignment claimed on SL's site. But the biggest contribution to non constant GD is due to 120 Hz HP. Look, and I am sure some will get po'ed at me for saying this. It's salesmanship. It's spin. It's 1/2 of the story. It's like that commercial, "I heard read it on the internet and you can't post anything that isn't true on the internet!" You read it and it sound very convincing, particularly to the uneducated. But if you question it and look at it the reality is that both a 1k Hz LR2 and a 1k Hz B3, with one driver inverted, have the exact same GD, and the DC GD of those two crossover is lower than that of a 1st order aligned to sum at the -6dB point. The 2nd and 3rd order cases also have a less steep variation of GD through the crossover region. So, if it is GD alone that is setting the choice, 2nd or 3rd order wins.
[edit] If you are really concerned with the GD, then build a linear phasze speaker using the Bodzio UE. Constant GD across the audion band. Period!
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My belief at this point is that vertical line arrays are excellent (quite possibly the best) for bass and midrange, but above maybe 1kHZ a point source might be just as good, maybe even better, depending on tastes. It's all about working with the acoustics of the listening room. Roger Russel (former head of acoustic research at McIntosh) is totally a fan of wideband floor to ceiling vertical line arrays. He has a fun website that talks all about it and much more (Google his name if interested). But even a short vertical line array like I have (4 five inchers per side) will have significantly less floor and ceiling bounce at mid and higher frequencies. Plus the narrower driver dimension relative to a single 8 inch driver is better for lower mid imaging.
I find it interesting when Linkwitz explains LX521 and Watson:
My current sound and video setup
I'm wondering how is LX521 different from Orion in a way Watson does not work ? Why ITD enhancement does not gain improvement ? The listening room is the same. Afterall Watson was low pass filtered speaker so lower midrange is the main contributor.
- Elias
My current sound and video setup
I'm wondering how is LX521 different from Orion in a way Watson does not work ? Why ITD enhancement does not gain improvement ? The listening room is the same. Afterall Watson was low pass filtered speaker so lower midrange is the main contributor.
- Elias
Perhaps because the bass drivers are physically decoupled from the higher frequency drivers, the vibrations excited in the framework where the bass drivers are mounted are less easily coupled to the carcase supporting the other drivers: these are the sorts of things I find make a considerable difference to the sound ...
Frank