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| Date: |
December 07, 2005 at 00:53:24 |
| From: |
norman bates, [oproxy.rockwellcollins.com] |
| Subject: |
mweh, your opinion................. |
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Impact is a tough one to define. A full ranger can seem to have impact simply due to the same source, not different drivers and phase problems causing nonlinearity (highs and lows arriving close to the same time). I've had 8" full rangers seem to have slam. Although there is a theory on that further down this post.
Really good bass is not subwoofer bass. Subwoofers 80hz and down doesn't have slam unless poorly designed (see later on why). Think of 40hz notes on an organ, even 60hz, or deep notes on a bass guitar that the fundamental is 10 or so db down compared to the first and second harmonic. Ive seen the rta graphic equalizers and to me it seems 60hz is pressure, especially in a small to average room, not an auditorium. But that is for the room mode discussions.
I've also heard of certain woofers in a 3 way were praised, described as having great slam, yet they did not have much power below 70hz at all. The drivers were small xmax (think less than 2mm). It is theorized that the bass driver was skipping past xmax (not nearly enough to reach mech xmax) creating upper harmonics of the bass notes.
My 3 way cerwin vegas with 15s have great impact yet severely need a subwoofer for rap. They seem to hit 70 or so hz then drop like a rock. And I've ran dual 15s from 80-500hz in a quad amp setup at home and there was much better impact on drums than with only 1 15, remember they were rolling off at 24db/octave @80hz.
Or another situation, take a subwoofer and compare it to a slot loaded push pull (think -20db first harmonic compared to a single driver). The single driver seemed to have more slam yet was shown on a spectrum analyzer to have really strong harmonics (which wern't in the original recording) (you can find an old aes on horns vs bass bins, think altec). The push pull I have has less harmonics, cleaner, less excursion, and due to less upper harmonic garbage has less slam (I run 4 18s), and is less noticible.
If anyone wants to test this, i would imagine run pulsed sine wave at 60hz and listen to it compared to 100hz. To me drums lowest harmonic is 60hz but i would imagine theye is way more energy an octave above this than at 60hz.
I'll say hi to mom for you.
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