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nl wrote:

However, these sorts of basshorns with twin 15" drivers and a very large mouth (larger than the cones of the drivers) have a long history. The Altec 210 cabinet, as used in the Altec A2 systems with two 515-type woofers, is a prime example. The engineers of these designs did actually know what they were doing, and made a series of engineering compromises. I can imagine what they are -- shorter horn length, smaller size, lower manufacturing costs and easier installation in theaters etc. Remember, these engineers were the very same ones that also made the compression drivers we use today like Altec 288, which typically have a 2:1 diaphragm/exit ratio. Some have an even smaller mouth, like the WE 555 which uses a 2" diaphragm and a 5/8" exit. While these are not "proper" horns in the fashion of midrange horns, nevertheless they have many horn properties such as increased sensitivity. So, they are not just funny-looking bass-reflex boxes either.

In many ways they are, nl. It is very simple to figure it out – just see where the horns stop EQ, let say 3dB, of the original driver response. If disregard the horn profiles and room loading then the delta between the sq inch of mouth and throat are important. The Altec 210 might not be considered in this case as they are also act like open buffers and therefore they (nether Knagfilm high-pass their horns)

nl wrote:

I think an interesting question would be: what are the various compromises made, and what are the results of those compromises? In some cases, the "compromise" might not be that important, for example reduced high-frequency extension might actually be an advantage overall. Thus, maybe we could come to a conclusion that "this is a good Altec 210-type design for those who must make those compromises, while this (other) design is best for those who can accept a ten-foot-long horn in their room."

Yes, it is trueand I see you point. However, I kind of always think more about sound reproduction then about loudspeakers making. Pretend somebody has special health need –100% oxygen to breath. You might feed the person with 50% oxygen and the person would not die, but your will also will not get out if this person the expected from him results. The same I feel with balance between compromises and design objectives. Sure, everything is compromise but let do not take 3 cub. inch enclosure and try to pull out of it 10Hz bass. We for sure can verbalize that it was good 10Hz bass for 3 cub. Inch enclosure but… something does not work for me in this logic. Can we name the multi-channel time-misaligned horns as Good Sound for random phase sources? Sound is Sound and has own needs, own inters and own agenda. I feel that it makes sense to talk about sound without mentioning the topology of sound reproduction. It sounds perhaps slightly minimalistic but in fact it is not.

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