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In the Forum: Horn-Loaded Speakers
In the Thread: Barn Conversion - James' Project
Post Subject: BasshornPosted by Johan Dreyer on: 2/5/2007
Romy
I think what I gained from the basshorns were 1. "Speed"or lack of momentum.Specifically deep notes on piano.The sensation of that leftmost keys with the initial impact then followed by the resonance from the instrument as separate entities.I hear this in real life but not in big bottomed speakers.The same with fingered double bass Note for note one can follow.I honestly can't say this is due to the horns per se.I do however believe that a single woofer with huge excursion simply cannot stop in time thus causing a boom instead of bom.Multiple arrays in a sufficiently rigid cabinet may however cause the same effect.I simply do not know.
2. I call this the "pulsating room effect" Here there is a sensation of the air in the room actually pulsating to the sound.This is not boom but a sense of sheer energy being transmitted.Unlike music simply being played way too loud and being unpleasant this is simply an awareness of the power of a bass instrument and- more remarkable- the air in the recorded space being excited by the instruments(not only bass instruments).We have all heard how ,on a good mid horn , a brass instrument (especially saxophone or trumpet) can simply leave the horn and gigantically excite a room.Exactly like a live instrument next to you can startle by its sheer energy exciting a space( A Trombonist I know calls it "picking up the room").That is what happens on a basshorn too.Again I hear this effect in real life too.I think it is the horn matching the impedance of the drivers to the room
Effect 1 I think one may obtain with multiple big motored drivers but 2 I have only ever heard in life and these basshorns.
The delay thing is a problem.I hear delays higher up as drivers become audible as individual speakers instead of a whole sound.I do not hear this in bass.I think you may be right about the arrays.They may simply create a whole room full of sound that makes the above effect inaudible.On the other hand they quite clearly image left right and depth too so I do not know.
But how to hear it? In setup I ran a sine wave at crossover freq through the system and watched the mic response(at listening position) on an oscilloscope figuring I should see 2 spikes in the reproduced sine.I saw none. This is probably nonsense but it made me feel better. I would expect to hear wide ranging instruments to "split in two"at the crossover, but I do not hear that either.Instruments not in one "space" i.e lower notes deep in the horn and the higher component out front? I have not heard that either.Never mind the old tap dance efffect of old WE horns.I think that only happens higher up.Bottom line :neither I nor my friends hear it so I stopped worrying about it. Maybe somebody can.Then I 'll worry again.
In early experiments I set up the lowermid/mid horns/tweeters up in my garage and used my Klipschorns as bass. I then moved the midhorns forward and back looking for time differences.That was very obvious from about about 1m movement.There the sound really did split into totally separate entities. It was so obvious I stopped the experiment immediately.
Maybe the 2m? pathway in the folded Khorn plus the additional 1m away.Maybe 3m or 9ms is the cuttoff for audibility at 180Hz?Maybe I am deaf...and stupid?A final thought.Maybe on Edgars subs(and the Khorns) what one heard was panel resonances at way above crossover freq causing a localising effect?Of course in a concrete and brick basshorn weighing many tons none of these resonances occurRerurn to Romy the Cat's Site