i wanna go All Active x-overs

Well, I have some suggestions, but realize I'm a newbie too...just one who is pretty good at research.

The MiniDSP units were originally designed to act as an active crossover. The EQ features were added later. Depending on your source, there are many different options for how to build the crossover. I'd been wanting to do a DSP crossover since the early 90s, and this is the first product I've found where I wouldn't have to breathe lead fumes to make practical (meaning I didn't want to solder bare chips to a custom board etc...).

I've been looking at some full range drivers, which seem to be able to cover the mid and high frequencies quite well, without the need for the downsides of a crossover. Another benefit is that the overall box size ends up smaller, which is great for surrounds. Check out Mark Audio--I've been looking at their Alpair 10.2, but have bought some of the cheaper CHR70 to experiment with. All of his drivers have an excellent reputation with FR fanatics.

A lot of what you're planning seems very similar to my interests. What kind of source/interface do you plan on using? I'll share what I know and I don't mind if you think or tell me I'm full of it.

well id be using spdif and/or rca for sources. i want lots of impact and dynamics, shooting for reference level 75db with the utmost clarity and still have some headroom to work with. i realize the in room db levels will be much more but thats what im shooting for. i already have 3 xpa 3's for power, so if i can use those for power with the minidsp units then thats what ill do. the reason i wanted each driver powered separately is for the simplicity of building standard rectangular cabinets and put in a single driver that covers basically the entire frequency range except 80hz and below. then it would be very simple for me to realtime analyze them and make the corrections. i could make the same exact box and use the same exact driver. then i wouldnt need to make a passive x-over, which i dont know how to do. i would need a larger miniamp like u said thou to make that work. 20x2 is not enough. ideally i would have amp power rms thats double the speaker rms.

but u said the minidsp can do what i want it to, so ill hold on to my current speakers for now and get those tweaked with the minidsp's.

those were some incredible looking drivers from mark audio, and they were really reasonably priced too. i may have to get a few of those here soon.

Hi.

DCX or MiniDSP are both excellent devices, and I'm also interested in active crossovers by Hypex, Rane, Tact, DBX, Dolby Lake.

But I believe you asked "What is the best?". The "best" is likely none of the above. It is, in my opinion, probably a DEQX HDP-3

http://www.deqx.com/products7.php

It is, in many respects, insanely powerful in its ability to integrate drivers into a cohesive loudspeaker. It is capable of making the absolute best loudspeakers in the world, plain and simple. 300db/octave crossovers with finite impulse response / absolute control over phase, the ability to get your frequency response down to a 1db window, and an included calibrated microphone with which to help design crossovers. Here is an article on it by Vance Dickason (of Voice Coil, also wrote the very informative "Loudspeaker Design Cookbook", and has designed some great speakers in the past)

http://www.deqx.com/assets/voicoil_review_feb2005.pdf

The tradeoff? It's very expensive. I can't imagine a full surround system using DEQX because of that. I can however imagine getting one DEQX HDP-Express (which costs less than the HDP-3 and has almost the same functionality) to cross over your main Left/Right speakers, a miniDSP to handle the center, and the hypex plate amps to handle surrounds. That would be my approach if I could afford it. I'm definitely a fan of miniDSP and how they cater to the DIYer rather than the pro audio segment.

yelis300 said:

get one of those, get some good quality drivers, then sit back and enjoy the show, or musical bliss if thats what ur into.

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As with any DIY Speaker, you still need great fundamental understanding and diligence to get it perfect. It's a powerful, powerful tool, but even the best tool is worthless if not used well.

what specs (t/s parameters) would you look for in a driver if you were gonna use this deqx hdp-3

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T/S parameters are not the way to put together a speaker. They make decent guidelines for a rough idea, but you need measurements, of things that a TS parameter cannot show. The most useful T/S parameter is Fs - resonant frequency. You need to make sure you are crossing over a good octave above fs, especially for tweeters.

I don't mind recommending you some drivers but I get the feeling you've yet got some learning to do.

t can take care of virtually all of the weaknesses in a loudspeaker?

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Whoa! It can vastly minimize the issues of crossovers. Loudspeakers have many, many weaknesses that you need to understand and address, that a DEQX won't "take care of"... Stored energy, power output, distortion, control of directionality etc are still things that contribute to the overall speaker.

would it just be a matter of the design of the enclosure?

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Not at all. Speaker design is sufficiently complex if you've never done it before! I highly recommend reading some books on audio reproduction and speaker design. Definitely read the works of guys like Floyd Toole, Earl Geddes, Vance Dickason, Ray Alden, Seigfried Linkwitz, Rod Elliot, and many others. On the bright side, it's a lot easier to fix "messing up" an active speaker than "messing up" a passive one.

forgot to add, the deqx site says that u could use one just for the fronts, and that they will become so cohesive that u wont even need a center channel anymore. it would create a phantom center channel. i dont know where i was going with that, it just sounded really cool to me.

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A good phantom center channel is excellent. However if you listen to recordings with discrete center channels, it may still be worthwhile to do a center. Not necessarily immediately, but eventually. My center channel will probably use a Seas or B&C Coaxial driver.

Ray Alden's book is probably an "easy" place to get started.

http://www.amazon.com/Speaker-Building-201-Comprehensive-Course/dp/1882580451

Although my advice is to build a passive 2-way based on someone's design on your own. That should really give you a better place to get started as it's a bit more "hands-on". It will give you a reference for what a great speaker should sound like, so you can try and "do better". You can eventually use it as a surround speaker. My suggestion would probably be an ER18DXT

But if you're serious about loudspeaker design, then as "complex" as that Loudspeaker Design Cookbook might seem, it's really the right level of "difficulty" to be approaching this with! But we can leave all that sort of discussion to another thread in the DIY speakers forum :neener: as the main focus here is that the DEQX is a very good tool but it's not "Speaker Building for Dummies". And remember, the HDP-express has much of the same functionality for less cost.