| Dedicated horn loaded mid -- big disappointment. [message #61169] |
Mon, 12 October 2009 19:26  |
noviygera
Messages: 23
Registered: June 2009
Location: United States
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Chancellor |
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I purchased a pair of front loaded horns with JBL e120 12" drivers. They are crossed over at 200 and 800Hz 24/octave
2 pictures here:
http://picasaweb.google.com/noviygera/Midbass#
dimensions are of the cabs are 28" wide-20" high and 24" deep.
When I hooked them up the sound was loud, very boomy, rolled off (as in muffled), and what really surprised me, completely lacking in detail and articulation. What is to blame here:
cabinet or driver? or both?
I was comparing these to my current 10" vintage Rola drivers on open baffle and there is no comparison. The open baffle is much more "natural" tone, detail and articulation of small music nuances, except for one thing: less efficiency and less boomy.
I am very interested in going the horn loaded mid bass "direction" but this negative experience completely surprised me. Why such poor performance? Any thoughts on this?
-Herman
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| Re: Dedicated horn loaded mid -- big disappointment. [message #61186 is a reply to message #61184] |
Wed, 14 October 2009 20:17  |
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Wayne Parham
Messages: 18789
Registered: January 2001
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Illuminati (33rd Degree) |
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You could try Speaker Workshop, which is freeware. For more information on things like what you'll need to get going, how to make measurements, what to look for and how to do it, see the Measurement forum, here on ART.
Measurements are best taken outdoors, free of reflections from walls that cause notches in response at distances that are odd multiples of 1/4λ. This is due to the fact that self-interference would combine at 1/2λ, which is excactly out of phase and subtractive.
On the other hand, if all you're interested in is higher frequencies, you can get away with working indoors. The process is called "pseudo-anechoic" and what is involved is setting up the measurements to send the signal and only capture what happens before the first reflection arrives. You do it with gating, which is setting the measurement "window".
Pseudo-anechoic measurements are a great way to get work done indoors, say on a cold winter day when you don't want to be outdoors. Since the crossover frequency is often where you're most interested, and since this is usually high enough to do pseudo-anechoically, that saves you from having to make all measurements outdoors.
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