Hi all!
I've posted in the past about how I found the Natalie P's a bit shrill and cold. So I decided to take some measurements. At first, I thought everything was OK, but then I found something was probably very wrong... (graph 1, measured.gif).
There's an almost 3 dB hump between 1KHz and 2KHz. This measurement was taken after I added 1 Ohm of padding to the tweeter, so as to try and tame what I perceived as too loud a tweeter.
So, I tried to find out if I had built the crossover wrong. The impedance plot is identical to the reference one, so I was really confused.
At this point, I went to PE and downloaded the impedance and frequency response plots for the RS180 and RS28. I then used LSPCad's KHF Tool to simulate diffraction from my baffle (which is identical to the one posted in the Natalie P's thread, except that it's deeper - 38 cms, actually), and simulated the crossover (with driver layout included) on LSPCad.
These are the results, with my measurements overlaid as a reference (Comparison.gif). They measured almost the same! (my measurements are quite poor, but in this case, they matched the simulation pretty well, I think).
I'm a bit confused. Could this be because I didn't round the corners of the speaker? I assume a 3 dB boost in this region would be perceived as a glaring midrange, so maybe this is what I've been listening to all along.
I played a bit with the crossover values, and got this as a result (schematic.gif).
It slows down woofer roll-off a bit, but it still manages to get rid of HF garbage, and it also eliminates the 3 dB hump I was getting, by changing 3 elements. (graph2.gif)
I wonder whether this is a step on the right direction (for my case), and how could I have controlled baffle step diffraction without modifying the crossover. I don't feel good about this, especially since I know this crossover has been built by countless persons and everyone has enjoyed it.... what do you think?
I've posted in the past about how I found the Natalie P's a bit shrill and cold. So I decided to take some measurements. At first, I thought everything was OK, but then I found something was probably very wrong... (graph 1, measured.gif).
There's an almost 3 dB hump between 1KHz and 2KHz. This measurement was taken after I added 1 Ohm of padding to the tweeter, so as to try and tame what I perceived as too loud a tweeter.
So, I tried to find out if I had built the crossover wrong. The impedance plot is identical to the reference one, so I was really confused.
At this point, I went to PE and downloaded the impedance and frequency response plots for the RS180 and RS28. I then used LSPCad's KHF Tool to simulate diffraction from my baffle (which is identical to the one posted in the Natalie P's thread, except that it's deeper - 38 cms, actually), and simulated the crossover (with driver layout included) on LSPCad.
These are the results, with my measurements overlaid as a reference (Comparison.gif). They measured almost the same! (my measurements are quite poor, but in this case, they matched the simulation pretty well, I think).
I'm a bit confused. Could this be because I didn't round the corners of the speaker? I assume a 3 dB boost in this region would be perceived as a glaring midrange, so maybe this is what I've been listening to all along.
I played a bit with the crossover values, and got this as a result (schematic.gif).
It slows down woofer roll-off a bit, but it still manages to get rid of HF garbage, and it also eliminates the 3 dB hump I was getting, by changing 3 elements. (graph2.gif)
I wonder whether this is a step on the right direction (for my case), and how could I have controlled baffle step diffraction without modifying the crossover. I don't feel good about this, especially since I know this crossover has been built by countless persons and everyone has enjoyed it.... what do you think?
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