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Multi-Way Conventional loudspeakers with crossovers

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Old 4th March 2011, 07:50 PM   #5121
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Yeah I've noticed that the three Johns seem to think alike

(John Sheerin, John Hasquin, and me (who's name is John, not Patrick.)

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Old 5th March 2011, 12:31 AM   #5122
gedlee is offline gedlee  United States
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Would someone with more experience than me critique my waveguide based on this plot? It shows 10 degree increments from 0 to 90. No crossover.

The baffle appears the same top, left and right, so I will therefore assume that this plot is a representative sample, and calculate a power response from it. I plan to feed that power response into my crossover simulator. Does this seem reasonable?
I'm guessing that this waveguide is very small, the axial hole is very low in frequency. I also suspect that there are some sharp edges or some room reflections because the response is rather rough. But its a good start.
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Old 5th March 2011, 08:31 PM   #5123
AllenB is offline AllenB  Australia
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Thank you.

I have plotted the power responses, simmed and crossed. In dealing with the acoustic phase I have boosted the tweeter by 2-3dB over target at 1500Hz. As this would have affected the power response, I may try undoing that and notching out the woofer instead.

Regarding baffle steps, I used to apply a simmed baffle step correction to an on axis plot, but now I see that this is close to pointless. BTW If anything, my bass is too high.

I rolled off the top end (4dB down at 10kHz). I'm still tweaking, but I just prefer it this way.
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Old 9th March 2011, 02:55 AM   #5124
AllenB is offline AllenB  Australia
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I have a curious reflection. Impulse response is not too bad for 10ms except for a reflection which I have tracked down to the opposite side waveguide. Quite ironic
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Old 9th March 2011, 03:32 AM   #5125
gedlee is offline gedlee  United States
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I'll tell you that that is a very clean impulse response - if its in-situ of course. The first impulse is clean, almost perfect with a nice extended gap of "nothing", then the room reflections. It hardly gets better than this and I have seen a lot. Nice work!
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Old 24th April 2011, 09:56 PM   #5126
jzagaja is offline jzagaja  Poland
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OS 12" with and without foam plug (Bulpren S28190). It seems foam attenuates uniformly.
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Old 28th April 2011, 07:09 AM   #5127
kstrain is offline kstrain  Scotland
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OS 12" with and without foam plug (Bulpren S28190). It seems foam attenuates uniformly.

While I have no reason to doubt you, it is hard to compare the differences in the figures without knowing the colour key. Could the ratio be plotted, or the figures normalised to the same peak value? (Or some other means to allow comparison of the change at >5kHz with the change at <1kHz, which you say is the same).

Ken
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Old 28th April 2011, 07:21 AM   #5128
jzagaja is offline jzagaja  Poland
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Take a look here:

Waveguides and horns
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Old 29th April 2011, 08:15 AM   #5129
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what are you using to do the plots?
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Old 29th April 2011, 08:16 AM   #5130
jzagaja is offline jzagaja  Poland
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Matlab and ARTA.
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