http://www.pesupport.com/cgi-bin/config.pl?read=400365

Bill Fitzmauice said(Bill told me by private email he won't post here anymore, but wouldn't say why, so we won't get him to reply here):

> Isn't it all about center to center distance
> in the dome tweeters?

"Yes and no. First, combing is not a major issue as far as the horizontal plane is concerned, only the vertical, so in most cases it's moot. What is of concern is lobed response, where the wavefronts aren't integrated at the radiating plane. Eventually those wavefronts do integrate, but if they don't do so well before the listening position then response will be jagged. To be confident of the result map the polar patterns of the individual drivers of the array and be sure that they integrate before the listening position, ideally no more than half the distance out from the array."

He's not specific enough for me to know what he's talking about. He does imply that the 30 inch .9 c-to-c distance dome lines(like I have, incidentally) have badly dropped high frequencies. Unfortunately neither me nor any of the people I've had over to hear them have said that. In fact, many have talked about the scintillating highs.

What gives here? More people who have never built a line array with no real idea of what exists? Don't know!!

If one does that, then one gets comb filtering unless one uses ribbons.

Marolboro

• http://www.pesupport.com/cgi-bin/config.pl?read=400442

In my research, which is considerable, THERE IS NO OTHER AVAILABLE DOME TWEETER than the Neo 20A, which can have its flange cut close enough to make the required center to center distance. The 1.25 or 1 inch models are too big and have a crossover too low, and the .5 inch models have a cross too high. All of them are usually too big to make the c-to-c distance.

I have to say that this is the reason why Jim and everyone else chooses ribbons or planars: only one possible choice for domes. And its a pretty inexpensive one. I'd like to find a dome specifically made that has a flange right up against the dome itself, and is more like a $10 quality each.

Marlboro

The Alpine domes in one of my vehicles is cut right up to the edge, and they are an awesome sounding low cost tweeter.

Brian

Marlboro