Project 81 -- 12 dB active 2-way Linkwitz-Riley alignment and phase coherenthttp://sound.westhost.com/project81.htmMy intentions are to use this 12db crossover to properly blend (crossover) my front channel B&W speakers, and an HSU subwoofer......which makes it a 2.1 channel system.Theory in short....The P81 is used on the output of my preamp and from there, is sent to 2 amps...highpass is sent to front channel amp, and lowpass to the subwoofer amp....crossed-over @ 80 Hz. What this does, is "relieve" my front channels from having to produce much below 80 Hz, an area that mini-monitors often struggle at (flabby, poorly-defined bass). and gives that responsibility to the sub. Plus, the crossover point will be well tuned, rather than relying on my sub's adjustable lowpass filter only (there's no highpass filter on my sub or preamp).The sub's one filter is defeatable, and the P81 alone, defines the crossover point for satellites and sub.I have built the P81, installed it temporarily in my system, and seems to be doing it's job.... (click on pic)(unshielded ?? noise >> NO << ....how about that ? :shock: )associated gear...http://www.hsuresearch.com/products/vtf-2-mk3.htmlhttp://www.bowers-wilkins.com/display.aspx?infid=2301&sc=hf
What my plan is, is to first take long measurements of the system with a digital cross-over. After I've settled on the cross-over frequencies & other things, I'm going to duplicate them in analog.
I just ordered the DCX2496, and from reading from diyaudio.com and various other sources there will be some problems with the unit, mainly with the CS8420 sample rate converter and the NJM4580 opamps used everywhere. Also the PSU might need upgrading.
I mean if you are mixing in a box and go the digital route to the DSP, use some good quality DAC's with reasonable slobe anti-aliasing filters then how can you go wrong? If you are missing details then there are probably some time-dependent issues like some kind of reverberation in the room. Flat on-axis response is not a measurement of transparent system anyway, it may be the off-axis response has some notches which prevent some room interaction
Hi Of course there is a bunch of projects on the net , but I never tried to build any of . I tried some old single-end design but there were a lot of dynamics issues and collorations. So, my question is do you know some accurate and "high end " design? Maybe some discrete design?
Sorry about the non-answer answer, but IMO the question is not which high performance circuitry to use, but what filter curves to target. Good luck.
Acoustics is done pretty well, and I claim that some details are missing because I compared system with similar but passive crossed speakers in same room. So, it measures flat, I don't have any EQ problems but i can't hear all details i hear on my passive monitors. At the end, I tried to do all passively but mine drivers are not ideal for passive crossover That's why I would like to try some analog active and to hear the difference. If that doesn't sounds "better" I can go back to DCX...
the nearfields I like is my new ones
ZD5's, look very pretty. I think there was a thread on building them at diyaudio.
QuoteZD5's, look very pretty. I think there was a thread on building them at diyaudio.Well I started from ZD5 but ended with something else Tonny Gee was kind to help me design completely new crossover.I also forget to mention that I experimented with DCX on this speaker too. Some transients are missing again
Reagarding the XO you tried with the nearfields using DCX was it similar topology (3rd order I guess if this is the one you implemented: http://i52.photobucket.com/albums/g8/mobidik/ZD5_nearfield_alternative.jpg )? Well, passive driver has to deal with real impedance of driver so you better measure the FR & phase of that nearfield crossover first (electrically directly from drivers, not acoustic response) and then reproduce that in DCX.
Also you could try this one (3rd order Bessel xo) with the mains:http://www.rane.com/note147.html
Many main monitors (in big studios) use horns and compression drivers for better transient response. It may be that even though the response looks good the soft dome tweeter can't do it with real stuff. I think you could try the metal dome SS 980000 (http://www.tymphany.com/d2904_980000) instead the SS 970000 you use (I assume D2905/D2904 have similar motor and need minimal changes in crossover). Also shallow waveguides like the ones Genelec uses should create no problems with diffractions (they are not real horns).
Here is another one on the net...."Moamps" / Passhttp://www.passdiy.com/pdf/articles/phasecrx.pdfhttp://www.passdiy.com/gallery/hi-lo-xover-p1.htmhttp://www.diyaudio.com/forums/showthread.php?postid=319300=FB=
I was thinking about MOX crossover, but that discrete opamp looks kinda funky. Not sure.... Did you tried that?