Active crossovers

[boroson]

I've been studying articles at Elliott Sound productions about acive crossovers, mult - way speakers and bi, tri and quad amping them. With my experience building a ClassD 254L, many other Dynaco, Hafler and Van Alstine amps (plus speakers), I think it would not be too difficult to construct an amp (two 254L's in one cabinet = 8 discreet amps) that could easily quad amp a system. ESP also has active crossover plans and boards available and all of this has my head spinning with possibilities.

I'm pressed for time at this moment due to a home brew session starting and I did not get a chance to do a thread search, but I'd like to hear about some actively crossed speaker projects. Drivers used, basic cabinet construction, etc. It seems like a feller could build separate cabinets taylored for each driver, stack them, adjust the vertical displacement (time alignment), etc.

What do you all think?

[Wushuliu]

What about using the MiniDsp? You can test out active xo's on the fly from your computer, and then it saves the configuration when you're done. I think I'll be getting one soon. Small and so cheap and does so much stuff...

http://www.minidsp.com/

[howard]

Hi,
I have a Rane 3 way elect xover and I have built several small boxes (~.25ft3) with tweeter and mid in them with the woofer in a separate box as a base. I have a Vifa set, Morel, Dayton, Audax, Usher and Scan Speak. Sometimes I like to mix and match. I have not used much technology to account for the alignment and such. I just keep tweaking until it sounds good to me. I hope to improve in this area in the future.
Howard

[boroson]

Thanks for the link the MiniDSP modules look very interesting. I will be studying the site over the next few weeks. There is a nice looking MiniDSP forum that looks good. It appears that one could build crossovers, equalizer and ClassD Audio amps in one neat case. Interesting.

[rhubarb9999]

This MiniDSP looks VERY cool.

If I understand it right .. $200 (2 units) gets a 3/4 way super flexible crossover AND 6 band PEQ on both the inputs and each individual output.

Looks amazing on paper .. wonder how it sounds ...

[charlielaub]

This MiniDSP looks VERY cool.

If I understand it right .. $200 (2 units) gets a 3/4 way super flexible crossover AND 6 band PEQ on both the inputs and each individual output.

Looks amazing on paper .. wonder how it sounds ...

Don't forget, each MiniDSP board is like an empty shell - you need to fill it with a "plug in" in order for it to do something. These cost $10 each, so you are looking at $220 for two. You will also need some sort of regulated power supply, one for each board if they will be located in separate places (e.g. in two different speakers).

No matter how you slice it, these ARE very interesting. If you purchase two of these, it's almost like having a Behringer DCX2496 that you can put INSIDE your speakers. I am building some modular analog active crossovers for speaker projects that I have slated. Even if build everything myself, I bet the cost will be at least $50 per speaker if I wanted to do a 4-way, even with 2nd order crossovers, like the MiniDSP. Also, you COULD make it so that you can remove the MiniDSP from one speaker project and put it in to the next one, so that you really only need two boards to provide crossovers for all your systems. You can only listen to one pair at a time anyway! To that end, I noticed that they do sell a version in a case, the "MiniDSP in a box", so that it could be external with only amplification internal to the speaker. Cool.

-Charlie

[Wushuliu]

This MiniDSP looks VERY cool.

If I understand it right .. $200 (2 units) gets a 3/4 way super flexible crossover AND 6 band PEQ on both the inputs and each individual output.

Looks amazing on paper .. wonder how it sounds ...

Some noise measurements here vs. Behringer, etc.

"Anyways, here's a frequency response measurement on one of my MiniDSP units with no crossover/EQ/delay/etc programmed.....into a 10k ohm load.
(Mine is a Rev. B board which explains the -7.9db offset.)

Noise floor (yellow) with a few other measurements as references. Stock DCX2496 outputs (red), line outputs from EMU Tracker-Pre (violet), noise floor of my measuring system (aqua.)"

I think any of the shunt-regulated PS boards at diyaudio could improve that even more...

[Deward Hastings]

Noise floor (yellow) with a few other measurements as references. Stock DCX2496 outputs (red), line outputs from EMU Tracker-Pre (violet), noise floor of my measuring system (aqua.)"[/I]

If I'm reading the comments at diyaudio correctly those noise measurements were taken with the same input and output voltages for both devices. In that case the DCX is not gainstaged correctly, and "wastes" nearly 20dB of its native signal to noise ratio. It may reflect what an amateur unable to deliver pro levels on the DCX input would see, but it's not really a fair comparison of the noise levels of the two devices either with digital input or with proper levels (different for the two devices) on the analog inputs.

[Ron_E]

I'm using the Behringer DCX2496 and have been very happy with it. I've also built systems around Marchand analog crossover board kits which I can recommend. http://www.marchandelec.com/ There's also been some recent discussion about Ultimate Equalizer on the forum. http://techtalk.parts-express.com/sh...d.php?t=220381

Ron