Originally Posted by NWCgrad
Yeah, the 2242 does have a pretty hearty rising response starting at 800 Hz. If not adequately attenuated it would really muddy the midrange. I have no issues with going with the 4th order on the lf.
No doubt I know a lot less than @A9X-308
on this topic and am always willing to learn.
In one of my early designs, I used a KEF B139 for bass with a 12dB slope to the mid at 300Hz or so. For ages there was a mid anomaly I and a friend could hear occasionally, but didn't show in the measured response*. It turned out the B139 had a sharp resonance over 1kHz. I built a notch for it and the problem was gone. Be very aware that out of band artifacts can turn out to be very audible with shallow slopes even if you think they're far enough out of band to be inaudible.
Another tip would be to not just focus on the FR, but other aspects such as distortion as well. Most drivers start to increase in THD at the lower end of their operating BW, but many do at the top as well. Just because the FR and acoustic slope on a midrange look good at 200Hz, doesn't mean that it won't perform better with a 300Hz xover because of something else like THD or maybe with a steeper slope. Just because the mid on your horn is going to give a nice roll off because it's in a small sealed enclosure, doesn't mean that it won't be better rolled off steeply. With a 200Hz 1st order you'll still be feeding it a significant amount of power below this and if the driver does increase in THD, the components produced will be in the active BW of the driver/flare and likely audible.
Before I moved back to Sydney, I had a very large 5 way front loaded horn system. It had been 3 years work and set up with as little xover as possible (it was powered by a monster own design tube amp**). Sounded great. But then I got the offer to try some new DSP xovers. On a whim, I decided to go the other way and try 8th order slopes. So with levels set I started to listen. It was one of the few jaw dropping experiences in audio for me.
In your response to my first post, you mentioned you'd read about what different slopes sound like: In my own experience, that's malarky. How many of those people have measured many aspects of the system to see what really
caused the audible difference? In my experience of the DIY world, very few. They just change the slope and declare the result.
* This was on an analog CRO with custom logarithmic amplifiers. And no capture.
** For those who've read my comments on tube amps here over the years, I did it because it was fun to design and build. It had a lot of SS in it, so purists hated it. It was also the size of a three drawer filing cabinet and for 50W class A, drew >1kW from the wall at idle. I used an SS amp at least as often and was no less satisfied.