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I.M. Distortion wrote :
      "...#1 from were you listen to system from you should be able to look down the throat of every horn in your system..."

jd wrote : 
      "...Hmmm... I will soon be able to verify this for myself..."


OK, I said soon... Last night I got home and tried angling the horns down toward my listening point.

For those who don’t know, I have made a horn system patterned after Romy’s Macondos. More on that and the differences between the two systems at end of post.

First I should say that the frames which will locate the horns are almost ready. In the mean time, I use a pair of modular metal racks, which I have adjusted for time alignment (not to within .001 of an inch, but as close as is reasonable knowing its temporary). The horns are normally all firing along parallel axes, straight out perpendicular to the rear wall.

So last night I angled the upper horns of right channel down toward listening point, and left the left channel with horns firing along parallel axes. The preamp I use has left and right volume controls, making it easy to listen to one channel at a time. I played a variety of music, trying to stick with mono recordings as much as possible while listining to only one channel.

Here are my preliminary observations listening to the right channel with upper horns angled down, as compared to the left channel with horns firing parallel :

Upper horns angled down (upper horns means 180 Hz fundamentals horn and the tweeter horn) :

1) « Tighter » sound when instrument plays a single note, I would say it was more in focus, but possibly less vibrant.
 
2) Possibly subjectively quieter (want to use one more click on the volume knob… a good sign I guess)

3) Flatter sound (as in less 3D space)

I thought it sounded good enough to take the time to angle the left channel down as well ; its sort of dangerous work due to the weight involved, but I wanted to hear it.

Both channels with upper horns angled down :

1) Game over in 3 seconds… Forget it… The space this system used to depict so fantastically had now gone completely FLATTTTTTTTT.

2) Notes sounded slightly dead and muffled by comparison (reminded me of the very nice box speakers I used to own)

3) Over all less captivating and less involving

This actually scared me ; what if I somehow couldn’t get the magic back (who knows man, maybe I had unknowingly hit the dPols jackpot ?). I put the horns back to parallel alignment, and happily the magic returned.

The new frames will make it far easier and safer to conduct this experiment again, and I will do it just to confirm these results.

I should add that had I never heard the system in its normal parallel firing configuration, I would have probably been impressed by the sound with horns angled down… It did still sound quite good, and I could have been fooled, I am after all an absolute beginner.

About getting this system up and running :

Since moving everything into a room that’s large enough, and putting the upper bass horns into the game, I just sit there in awe. The first night I was literally on my ass in amazement. I told myself no way is this possible… Such warm delicate detial is now filling the space, and what space! Really, I was quite certain that I was just too tired and was imagining this sound. The next night I told myself no way; must have some freaky good electricity here tonight… I gotta get some sleep ! Two weeks later and I am still on my ass. My life has come to a screeching halt. I don’t get anything done… Don’t ever get to sleep before 3 a.m. Don’t leave the house other than for work ; have been pulling on dirty clothes because I just can’t stand the thought of hearing the washing machine in the background… I am quite sure I will forever be single and I just don't care.

Romy you may take this all as a compliment.

Main differences between Romy’s Macondos and my horns, or where I would take the Macondos :

I use a larger top or "fundamentals" horn (180 Hz cut off vs Macondo’s 250 Hz),  which I do not attenuate at all. Consequently, the upper mid range horn (400 Hz ; same as Romy’s) is high-passed electronically at a higher point (4800 Hz 1st order), and the upper bass horn is not asked to play so high.

Relieving the small (400 Hz) horn of some lower frequenqies allows use of the original metal-suspended diaphragms in all four S2s.

I don’t use an injection channel ; My mind could be changed, but I do feel that I get the very nice tone via the above-mentioned diaphragms along with the drivers I use in the upper bass horns (115 Hz cut off ; same as Romy’s) : Old paper cone drivers with big AlNiCo magnets.

For tweeters I use (and love) the Electrovoice T350, which I high-pass at 12 KHz 1st order (well ok, I love one of the two pairs I have… For whatever reason, the other pair is not in the same league). I have zero motivation to try other tweeters.

This system still lacks true dedicated mid-bass horns (pair of 45 Hz straight bass horns "coming soon"), but the upper bass driver goes really low before rolling off, and I do let it go there for now. Also I use a pair of extreme low frequency enclosures, which I currently allow to run up to 90Hz 1st order, so a bit higher than will be the case once the mid-bass horns are done. Romy does have true mid bass (via a pair of line arrays).

The lower bass enclosures are responsible for a lot of the magic (pair of 16 cu ft sealed boxes), and they are very much a part of the system. The drivers have a really easy life… The cones don’t seem to move at all ; but switch them off to hear what they’ve been doing. It doesn’t matter what the music, at the very least they will tell you a lot about the recording space.

I don’t have a pair of Melquaid DSETs. I drive the horns with a pair of Lamm ML2s, running full range. I use a second pair of M1.1s for lower bass. The ML2s are hard to fault. In fact at this point, I can only find positive things to say about them. When I finally identify a good reason (sonic) to do it, I will try building a pair of DSETs… If the 45 Hz horns don’t kill me first.

Jd*

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