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Dear Romy,

OK, some more about the midbass.

Well, it was not really a surprise to us that the horn without the phase plug was dissapointing. Without the plug we had a horn that was a bit too short, had too large front cavity and less compression than we desired.

So it is nor really fair to say that the plug always is better, but in our design the plug is crucial since it is a part of the horn and helps connetcing a rather large driver to a small throat.

The goal was not to investigate about plugs but to make the horn. It would require a good deal of work to extend the horn to the same length as with the plug and reducing the front cavity to the same volume which would be needed if we should really test the plug. I do not think I will do this since I am happy with the result.

Under 500 Hz? With slow rolloff filters we still have some energy rather high upp in the MF range. We wanted to the directivity in the upper region of the midbass be close to what we have in the lower region of the MF. I think that the phase plug could be a way to achieve this.

As an example take a typical High End system with a crappy 8" woofer and a crappy dome tweeter crossed at 2-3k. The woofer will clearly beam at 2k and the tweeter will have a very wide distribution. The crossover from the woofer to the tweeter is easy to hear and can not be considered seamless. Of course we want something better than this.

I think that directivity in the crossover region matters quite a bit if you want to make it sound seamless.

On an other more disturbing matter: How can we use MF up to the region of 10k with a driver that has a 200Hz phase plug?? This will give a large amount of distorsion!

One more worrying issue: How much overlap should we have in the crossover region. I made a 1100Hz tractrix for 1" drivers and tried it as tweeter HP at 9k. It was easy to hear that it had better bottom than the normal tweeter. So if we want to use MF from 500Hz would a 250Hz horn be enough?? Or should we have to use a 100Hz. This issue gets even more disturbing when we consider the midbass!

I have not tried the Fane 8M. On paper it does not look that attractive, but it still might work well as you said. Quite heavy diaphragm though.

I tried some Fane tweeters which I found to be aggresive and metallic. Which reminds me....tweeters. Still a problem!

Best Regads: Ulf

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