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High crossover slopes will minimize lobing when you cannot get the driver acoustic centers concentric.

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Walt

Lobing definitely makes the speaker sound crappy. Any slight movement of your head creates changes in timber.

I used that as a DSP crossover technique on a pair of VMPS RM40 speakers with the ribbon center and it worked much better than the original passive XO. The guy gave me the RM40's as he could never get them to his liking.

Dave,

Curious. How does the radiation pattern of 7” tall ribbon tweeter interact with circular radiation of the mids? I presume the G1 radiation is predominantly horizontal.

To my ears they work quite well together. I can't say that I notice drastically different sound when I stand up and move about the room than when I'm sitting in the sweet spot.

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I have too much stuff - https://www.pleasebuymystuff.com

I've had a DEQX for several years now. If you're not familiar with the DEQX products they provide an electronic crossover and room equalization all done in the digital domain. Since I'm all digital all the time this works out well for me. Several filter types are available including Linkwitz-Riley and Butterworth. I don't use the room equalization, but I did use the equalization feature to provide the low shelving filter that the NHT subs were designed to use.

At one point I decided to prove my theory that steep crossover slopes did indeed sound worse than the more typical 12-24 dB slopes. The results did not match my expectations and quite a few people agreed that the 96 dB slope crossover did sound better than the 24 dB slope I typically use. It does make sense, at least to me, that if different drivers aren't duplicating efforts there's less of a chance they will not be reproducing the overlapping frequencies identically. Two drivers with different characteristics will not reproduce sound identically no matter how well matched they are. They may be close, even remarkably close, but exactly the same? I don't think so.

A 96 dB slope crossover minimizes the overlap, you can hear the sound get cleaner and better defined as the slopes get steeper. That's what everyone I auditioned the test blind to said. There were no exceptions.

All that said, I'm using 24 dB slopes with the DEQX because I also want to be able to run the speakers full range from a single amplifier and I can try different things relatively quickly and easily with the DEQX that would take a lot of effort in the analog domain. I'll likely go back to 96 dB slopes when using the DEQX after I've finalized the analog crossover.

More comments on the DEQX vs. a passive crossover to follow.

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I have too much stuff - https://www.pleasebuymystuff.com

If anyone would like to come and take a listen to these I'd love to hear your honest feedback. As long as you're vaccinated you're welcome to swing by. So far, feedback has been extremely positive. I've had a few comments that have prompted minor changes and welcome more honest feedback. I've said it twice, I'll say it once more, I want HONEST feedback.

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I have too much stuff - https://www.pleasebuymystuff.com

I had the fun of play around with Dave's speaker for a couple of days.

For those that were inquiring about the radiation pattern, below are some graphs that show:
- response at the suggested listening axis (10 or 20 degrees)
- horizontal dispersions 0 - 70 degrees,
- vertical +/- 0,5,10,15 degrees, and
- phase matching - which I thought was excellent phase matching, as evident by deep reverse null (on and off-axis). The crossover was 1,550hz.

I thought the speakers sounded pretty damn good - but I was too nervous to push ribbon tweeter (since it's not mine ).

Ignore the SPL magnitude and slight wiggles, that was due to reflections creeping into the impulse response.

Amazingly flat response
When I heard them back in the spring I could easily tell the speakers had a wide rang
There no screaming meanies.
Quite an accomplishment