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Multi-Way Conventional loudspeakers with crossovers

Introduction to designing crossovers without measurement
Introduction to designing crossovers without measurement
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Old 13th April 2018, 07:21 AM   #611
Lex vs Kingpin is offline Lex vs Kingpin  Turkey
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Originally Posted by AllenB View Post
The power rating of resistors should be high enough that they are not damaged by heat. It is not simple to predict how much you need. Low efficiency drivers, and woofers, and when used at high power, need to be larger than high efficiency drivers, and tweeters, and when used at low power. The resistors I use typically vary between 1/4W and 20W. It is OK to use a resistor with a higher power rating than you need. It can be useful to have a stock of 5W resistors of different values to use. When you use them on a woofer, it is best to play music through them then feel them. If you cannot keep your finger on them then you need to be using a higher rated part.

If your tweeter impedance is smooth enough to work with then you don't need the parallel resistor.
Thank you sir! I will continue the calculations. Best.
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Old 26th August 2018, 01:17 AM   #612
nigelb63 is offline nigelb63  United Kingdom
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Bloody excellent tutorial,Allen. Any chance of you and a whiteboard on YouTube?
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Old 26th August 2018, 01:33 AM   #613
nigelb63 is offline nigelb63  United Kingdom
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Originally Posted by DBMandrake View Post
While attaching foam near the edge of the baffle can reduce the ripples in the response (particularly on-axis) caused by baffle edge diffraction, the basic baffle step shift in response of 6dB will always remain regardless of the type of damping material used. All you're doing is getting a little bit closer to the theoretical smooth 6dB shelf response of a sphere, with less overshoot than you might otherwise get with a rectangular baffle.

I'm sure you know that, but some people reading could possibly mistake your comments to suggest that somehow the basic 6dB shift was being reduced, reducing the need for baffle step correction, which isn't the case.

With typical edge radii of front baffles I'd also suggest that foam is only effective above about 2Khz or so, and only at frequencies where the active driver has wide enough (180 degree) dispersion to illuminate the baffle in the first place.

For a midrange driver you would probably get more reduction of baffle diffraction ripples (especially below 2Khz) by simply offsetting the driver a bit, and for a tweeter (which is where the foam would be most effective) you can more or less eliminate baffle diffraction by using a tweeter incorporating a waveguide - on many such designs little or no signal is radiated at right angles along the plane of the baffle so there is nothing to diffract from the cabinet edges at those frequencies.

Whether there is any worthwhile effect depends entirely on the directivity of the drivers - small drivers with very wide dispersion may see a significant improvement, larger and/or directivity controlled drivers won't see any useful improvement in my experience.

Certainly worth trying though.
Hi Simon, what would you class as a “typical baffle radii”?
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