Preamp, digital crossover & room correction for 3 way stereo - DEQX HDP-5, Trinnov, other?

Regarding selection of a dealer, I would highly recommend Nyal Mellor of Acoustic Frontiers. He carries both DEQX and Trinnov. I purchased an HDP-5 from him about four years ago, and I could not have hoped for a better purchasing experience. He is extremely knowledgeable, helpful, and sincere, and will go out of his way to be sure his customers are happy with their purchases. He also provides a free one hour or so consultation/tutorial following purchase, via the Internet + telephone.

As far as the microphone is concerned, I purchased the optional Earthworks-based "reference calibration kit," which I would highly recommend vs. the much lower quality mic that comes with the HDP-5 as standard. Also, you'll want to purchase a mic stand separately, if you don't already have one. B&H Photo/Video is my go to place for that sort of thing.

IMO the only downsides of the HDP-5 are:

1) The learning curve that is required, at least if you choose (as I did) to do it all yourself and not utilize their DEQXpert service.

2) If you choose to utilize the speaker calibration/correction function (as opposed to the room correction function), which as you probably realize requires measurements to be performed with the mic positioned within about 2 or 3 feet of each speaker, room reflections reaching the mic during those measurements must be minimized. In my case I did that by moving the speakers to the center of the room, one at a time, placing sound absorbent panels (ordered from B&H) along the nearest walls or other reflective surfaces (which were about 6 feet away), and placing a pillow on the floor just in front of the speaker. That worked out reasonably well, although measurement in a larger room (mine is 22 x 13 feet) or even outdoors would have been more ideal.

Good luck. Regards,

-- Al

So you know, building an active speaker still requires proper time/phase alignment just like with a passive crossover.

So you'll need a way to measure the drivers and driver combinations to ensure proper integration with each other.

Too often I've seen beginners just guess at crossover slopes and use the EQ to beat them into submission. Ugh.

Excellent point, Erik. And as you may be aware time/phase alignment is the major purpose of the speaker calibration/correction function provided by DEQX.  

As I mentioned earlier, the more room reflections can be minimized when the necessary close-up measurements are taken for that process, especially reflections having early arrival times, the better the results will be.

I'm not familiar with how Trinnov handles the corresponding process, if in fact it provides a speaker time/phase alignment process that is separate from room correction.

Best regards,

-- Al

Hey Al,

Right. I'm not sure how that works either. Speaker design (active or passive) involves a number of choices. Filter points, slopes, eq, etc.

About the only thing you don't worry about as much with active is the impedance curve and filter interactions, and of course, buying several parts you aren't going to use in the final product. :D

But setting the filter points, and telling the room correction software to handle the EQ won't solve beam or lobe issues.