Dear Spookydd,I have a larger project for a multi-amp 4 way system and I want to design the best 4 way active crossover filter possible, and keep it buildable as a DIY project, so I want to avoid any SMT type of stuff. Although careful choice of opamps can allow 2 versions of PCBs made, one through-hole and the other could be SMT.
I have all my speakers made and I plan to have a kind of short rack on wheels to house all the power amps, the crossover and all the electronics needed, including a micro-controller based management of the whole thing to automate it so no human intervention is needed on the rack itself, not even to turn it off.
The type of filter chosen is Linkwitz-Riley 24db/oct, making use of all-pass filters to correct the phase differences.
The tentative crossover frequencies chosen (for now) are:
150hz
1.5khz
8khz
Certain things remain to be debated, as far as eventual additional adjustable delays on some bands to compensate for physical alignments of speakers. My speakers are adjustable, as each of the 4 ways is in its own cabinet and they are on top of each other, thus can be physically adjusted, to a point. But perhaps having an extra adjustable delay to correct for some of the physical alignment that can't practically be made, could be useful.
The input needs to be balanced, to allow for long signal cables, while the amp racks would be positioned very close to the speakers, to minimize the speaker cable lengths. I expect the longest power cable length not to exceed about 2m, probably even less, at least for the tweeters, that are way on top of everything else. The bass power cables might not even be much longer than about 1m.
Sorry for the us based diyers, as I work only in metric
Attaching a rough synoptic of the crossover.
Did you finish your ASP project?
If yes, are you offering the ASP as a DIY package or even a finished package?
I know, it is six years since you mentioed this project, but I do hope you have had success.
Hoping to hear from you.
Subhash 2016
All this is still on the agenda, and it actually has been far more than 6 years since I started working on it.
I haven't been able to work on the hobby for some time now, which bothers me quite a bit, but I surely will get back to work asap, when I get through the backlog of other (paid) work that I've been taking on over a year ago..
The larger project will have to grow from the parts that I've been working on. One of those parts was that 4 way x-over that I was last working on. I also was working on a headamp roughly at the same time.
There is some automation electronics to figure out to bring everything together in a coherent system, to integrate all that stuff into that short rack on wheels that I mentioned before. With 4 power amps, the 4 way x-over, supplies and automation housekeeping, all in one.
What do you mean by "ASP"? At the moment I'm not sure what that acronym refers to.
Of course everything I do will be shared, although this may not be quite for everyone, due to the magnitude and complexity of the system.
Basically, the plan is to have a short rack with all that power stuff to be located right next to the speakers, probably in the rear, with super short cables going to the speakers. That rack should no require any access once in place and would turn itself on and off on its own when needed. It would go in a very low standby power mode when not needed, ready to turn itself on when an audio signal is sent to it, and go back to sleep when audio has been gone for a certain timeout.
4 ways may not be for everyone, so I suspect rather few would be interested in the whole shebang.
I will design the racks and will also share the mechanical design data for whoever wants it.
I have mostly built a prototype of that 4 way x-over, and I haven't started to power it up and test it yet, but it was very close to that when I was rudely interrupted by other work. When I finally get around to it again, I will be at the point of testing that prototype, and then the headamp prototype will also get some attention, as it's roughly at the same stage as well.
Just a matter of time, it remains very much on the agenda.
Cheers,