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Since the “no tilting rule” is one of the Macondo’s Axioms: (#2 - “All channels shell have strictly parallel axis”) then I would like to defend it.

be wrote:

The time alignment will depend on the geometrics of horn set up and listening position, in the same manner, no matter if the horns are tilted or not. It is simple: delay=(distance of ear to source)/(speed of sound)

It is just logically appears this way but unfortunately it is not so in reality. I do not know well theories behind all of it – my understanding and knowledge has more applied, practitioner outlook to those things – so I declared the harm of tilting as a practical fact but I do not explain the physical nature of this phenomena – I just do not know it. Interestingly I even never asked myself about the underlying reasons. I admit it would be interesting if somebody explain why tilting screw up arrival time but I am too pragmatic to dig in it myself.

be wrote:

I dont see why non tilting should have any advantage over tilting.

Ok, let me to explain. Take MF and HF drivers, position them strictly parallel and perfectly align them from 5 feet and listening position directly on the axis between the drivers.  In this case the driver’s cones will be strictly perpendicular to the main axis and equidistant from the listening position.  Now tilt one of the drivers for 1 degree and recheck the alignment from the same from 5 feet - you will be off. Now re-align the non-parallel drivers again. After you hit the alignment you will see that the equal proximity between the listening position to the driver do not exist anymore and the tilted driver will be in time-aligned setting closer or further then the non-tilted. Let call this tiny change of alignment distance with tilted drivers as the Tilting Excursion

Here is where the whole notion of drivers tilting hits the fan: the changing of listening position distance will demand a different Tilting Excursion. With the parallel drivers the Tilting Excursion juts do not exist. 3 feet, 5 feet, 10 feet – all the same: (distance)/(speed of sound). With the tilted channel you need to introduce a correction – the Tilting Excursion -depending of the listening distance.

The only know to me way to correct the thing is to wear some kind of detector on the listener that will read the distance to the driver and dynamically tilt one of the drivers contingent upon what the listening distance is. One would say: “Well, how about if the listening distance is very firmly set?” Then it should be fine, though I would have my concerns with the alignment at one octave above and before the crossover point in this case and I fell it might be the problem.

Take any loudspeaker with tilted baffle for done tweeters: Grand Slamm, Utopia and so on and take a look how dramatically HF sound changes with them whiles you move closer and further from them. BTW, GOTO officially “do not believe in time alignment” but they recommend tilting the drivers “until you get better sound”. Now you understand what kind BS they propose. BTW, if you have 2 channels with one cone plus 5 degree off the perpendicularity to the main axis and with another cone minus 5 degree off the perpendicularity to the main axis and the channel are time-aligned. Then you will have a perfect listening position no deeper then 1-2mm and you can very much listen in this case in a dentist char. As soon your hear move 1mm off then it will sound like somebody just put a ton of new Black Gates capacitors in your amplifiers….  if you know what I mean. :-)

be wrote:

Actually if one is so close to the horns that one or more of the the throats get obscured from vision by the inside of the horn walls, then the necesarry bending of the sound path will increase the changes of delays, when one is moving around.

I think the diffraction has nothing to do with it as the effect is clearly observable even with the direct radiator dome tweeters.

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