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Multi-Way Conventional loudspeakers with crossovers

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Old 18th December 2007, 08:14 PM   #11
crazyhub is offline crazyhub  France
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Join Date: Nov 2005
Location: alsace
I really don't see where you guess a problem.
You say 0.3% THD at 100/105db is respectable...I would say it's uncommon with non horned drivers!
And where is the problem with +/-2db on a small fr range right before uppermid?
Personally, if I had a doubt with this design it would be in the field of the off-axis energy in the uppermid because cutting a 145cm2 SD near 2Khz isn't quite ideal. With such a SD, nondirectional piston range begins close to 800Hz.

About the inner shape of the mid enclosure, sure such small bumps and valleys have less than an effect but the global shape has no // walls and this helps reducing standing waves.

Just my 2 cents.
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Old 18th December 2007, 10:16 PM   #12
Pan is offline Pan  Sweden
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Well the problem might be that the driver has increased distortion around 1k and that indicates something is going on. Yes the driver is a good one but hey, let's strive for perfection okay?

There are some drivers that perform equally good or better in part of the range, even non horn loaded drivers.

Wether the increase in distortion is a problem or not is hard to say of course without an in depth investigation of the driver. However if the distortion is of a type that is not increasing gradually but instead suddenly shows up, then the audibility might be worse..and such distortion is also often plauged with higher order harmonics.


The problem with +/-2dB ripple in a small range.. well it indicates once again that something is going on that shouldn't be there. It's just to much of a deviation from the raw respons of the driver indicating (likely) stored energy and/or difraction not dealth with sufficiently.

The enclosure will more or less behave as there is a back wall. Standing waves does not dissapear just because the shape is altered from a cube. A standard internal shape where the reflection is damped with something more effective than sheep wool would likely produce better results.


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Old 19th December 2007, 05:11 PM   #13
crazyhub is offline crazyhub  France
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Quote:
Well the problem might be that the driver has increased distortion around 1k and that indicates something is going on.
I don't see any increased THD around 1Khz on the rare plots on the net, only one huge breakup K2 near 5.7Khz where the two ears transform it into two reduced bumps, even no K3.
Quote:
Yes the driver is a good one but hey, let's strive for perfection okay?
I don't know of any perfect driver except perhaps in heaven if God is an audiophile addict, do you?
Quote:
There are some drivers that perform equally good or better in part of the range, even non horn loaded drivers.
Yes some floppy drivers that smooth the upper mid; up to 800-900hz I'm not sure at all they are on par with this one.
Quote:
+/-2dB ripple in a small range.. well it indicates once again that something is going on that shouldn't be there. It's just to much of a deviation from the raw respons of the driver
The raw driver (IEC baffle?) DOES show this ripple; whatever it's due to, I won't take much more care on this because of the very small level of THD and a low level of energy storage that can be seen on the waterfall plot.
Quote:
The enclosure will more or less behave as there is a back wall.
A rounded one...this helps...no rear wall at all doesn't much more help because of the huge impedance difference between inner air area plan and exterior.
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Standing waves does not dissapear just because the shape is altered from a cube.
They are smoothed on a larger fr range.
Quote:
A standard internal shape where the reflection is damped with something more effective than sheep wool would likely produce better results.
My point of view on this matter is: killing/avoiding standing waves before applying less dampening material which will then act more linearly without killing too much dynamics. But I agree that this applies more on bass drivers than mid drivers.
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