How to measure an active speaker system?

[Tyson]

I have a modded DCX and I've got it set up to sound pretty good, based on the published specs of the drivers. I also have a calibrated Dayton MM6 mic and an M Audio USB Preamp. But I have no idea how to make any kind of measurements with them. Most of the programs out there seem to be geared toward measuring and building for passive crossovers, not for active ones. The drivers I'm using is an SB Acoustics SB29 tweeter, and a single Peerless HDS Nomex 830875 as a midrange, and then three of the 830875's as bass woofers.

Basically I built the Elsinore DIY speakers which are MTM-WW, didn't like the way they sounded, so I reconfigured them to be MT-WWW. I think it's because I'm in such a small space, the midranges were spaced too far apart and I don't sit far enough back for them to properly integrate.

Anyway, how can I do some measurements with the drivers in the box and in the room? I don't have the ability to take the speakers outside, unfortunately. Measuring phase is also important to me, but again, I have no idea how to do it....

[boconnor]

Originally Posted by Tyson

Anyway, how can I do some measurements with the drivers in the box and in the room? I don't have the ability to take the speakers outside, unfortunately. Measuring phase is also important to me, but again, I have no idea how to do it....

It depends on what you want to do with the measurements.

If you want to correct the combined speaker/room response, then you can measure from the listening position and use correction software to tell you what changes to make in the frequency response.

If you want to adjust the speaker responses independent from the room, then you'll need to do some quasi-anechoic measurements (close mic techniques with time windowing filters). Its a bit trickier (and less accurate) than putting your speakers in an anechoic chamber.

In either case, there is good software on the net (free and payware) to help you do it. There is some info on my thread about how I am doing room response measurements and changes, which might help: Digital Room Correction Project

[Pano]

Have a look at the HOLMImpulse software. There are 2 threads on it in this forum.
It's very, very good and it's free!

The FRD Passive Crossover Designer (runs in Excel) also does active filters. Another very good free software.