Hi everyone,
First time posting here. This gentleman crossed a tweeter at 1800 Hz. However, the tweeter's Fs is 1200 Hz. I did know that was possible. Should one not stay at least an octave above Fs. Would someone care to explain this a little more?
I have been wanting to build a central channel with these or similar drivers.
This is the link:
http://member.newsguy.com/~stigerik/html/body_gnurk.htm
Thank you in advance
First time posting here. This gentleman crossed a tweeter at 1800 Hz. However, the tweeter's Fs is 1200 Hz. I did know that was possible. Should one not stay at least an octave above Fs. Would someone care to explain this a little more?
I have been wanting to build a central channel with these or similar drivers.
This is the link:
http://member.newsguy.com/~stigerik/html/body_gnurk.htm
Thank you in advance
The closer you get to the fs of the tweeter the more you need a series notch filter (to even out the sharply rising impendence of the unit --- unless you use ferrofluid - or something! - tweeters...
However, the main problem with getting to close to the fs of a unit is that the cut-off rate of the filter is usually just 12/ 24 db/oktave
meaning you still play rather loud below cutoff because the filterslope is too horisontal ... a 6db filter fx would only be -6 db down at 900 Hz if cut-off is 1800 Hz...
At loud levels that would lead heavy distortion and possibly blowing the tweeters after a while, depending on the quality of the unit.
Hobbes
However, the main problem with getting to close to the fs of a unit is that the cut-off rate of the filter is usually just 12/ 24 db/oktave
meaning you still play rather loud below cutoff because the filterslope is too horisontal ... a 6db filter fx would only be -6 db down at 900 Hz if cut-off is 1800 Hz...
At loud levels that would lead heavy distortion and possibly blowing the tweeters after a while, depending on the quality of the unit.
Hobbes
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Joined 2000
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While I am not an expert in this area, there are a few general guidelines that are often followed. I'm sure others will chime in...
In many applications (typical second order XO?), it is recommended that you cross at tweeter at 2-3 times its resonant frequency (Fs). If you use a higher order crossover, you may get away with crossing it at a point that is closer to the resonant frequency, and maybe 3-4 times Fs for a first order crossover.
With woofers, a recommended point is to low pass the driver at a point where the responses at 0 degrees and 30 degrees off axis remain within 3-4dB of one another.
In many applications (typical second order XO?), it is recommended that you cross at tweeter at 2-3 times its resonant frequency (Fs). If you use a higher order crossover, you may get away with crossing it at a point that is closer to the resonant frequency, and maybe 3-4 times Fs for a first order crossover.
With woofers, a recommended point is to low pass the driver at a point where the responses at 0 degrees and 30 degrees off axis remain within 3-4dB of one another.
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