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Multi-Way Conventional loudspeakers with crossovers

Microphone position - theoretical phase shift delay
Microphone position - theoretical phase shift delay
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Old 8th November 2019, 08:33 AM   #31
kimmosto is offline kimmosto  Finland
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I guess all this hassle starts from selection of design tools and methods which are designed for single mic spot measurements and simulation. Calculations and timing settings are needed to move virtual mic in the simulation to some other location than where actual mic was located while measurement of drivers. For example if all drivers of multi-way were measured at 987 mm to 0 deg and virtual mic in XO simulation is at 2345 mm on tweeter's axis. New calculations and settings are needed if designer wants to move virtual mic to some other distance or elevation. Response is not so correct anymore if driver is simulated to some other off-axis angle than measured. Off-axis simulation needs also reloading measurements.
No one forces to do that, but maybe self punishment is fun and making life of some others more difficult by recommending limited tools and methods is satisfactory. Few examples^
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Old 8th November 2019, 10:18 AM   #32
Juhazi is offline Juhazi  Finland
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I don't think that we have a hassle here, in this thread.

This started as a simple question of one specific phenomenom, how to understand it. Tolvan's Edge and XDir aren't design tools either, but just little visualizers to study a question like the one here.

Basics of an acoustic transducer's behavior in the baffle, off-axis radiation changes per wavelength, interferences with baffle and other transducers etc. must be deeply
understood! Simulations and design programs are combining all this, to the best they can.

Off-axis radiation pattern measurements and simulation is a modern trend, made rather easy by eg. VituixCAD. Designers typically do measurement and simulation to a single distance, typically at approximately 1m because of difficulties of measuring indoors (quasi-anechoic) simulation for design should be optimized at eg. 2,5m.

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Old 9th November 2019, 05:13 AM   #33
classicalfan is offline classicalfan  United States
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The measurements resulting from two tweeters mounted on the same baffle are very well explained in this video by Danny Richie of GR Research:

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Last edited by classicalfan; 9th November 2019 at 05:18 AM.
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Old 10th November 2019, 08:23 AM   #34
Rick PA Stadel is offline Rick PA Stadel  United States
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Sorry, AllenB -- I didn't say that right ..

What I was thinkin' was, "It is awfully easy to find oneself overly invested in the trig -- quite unnecessarily -- considering the many fine, modern tools available."

Apologies ... I'm still trying to learn to write!

And Thanks, Juhazi, for a couple of excellent examples.

-R

Last edited by Rick PA Stadel; 10th November 2019 at 08:37 AM. Reason: forgot something
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Old 10th November 2019, 08:41 AM   #35
AllenB is offline AllenB  Australia
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No problem Rick, I was just being pedantic
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Old 10th November 2019, 07:22 PM   #36
kimmosto is offline kimmosto  Finland
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Measured or simulated vertical off-axis data, few wires and blocks. Driver locations, tilt, delay and other adjustments and that's it.

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Old 10th November 2019, 08:47 PM   #37
Juhazi is offline Juhazi  Finland
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Thx kimmosto! Can you show simulation at 1m vs. 2.5m ?

andy2 post #4 "My real question is that some speakers are measured at say 1meter between the tweeter and mid driver. But there are speakers are measured at listening position such as 8ft length, 37in. height (or somewhere about there)."
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Old 11th November 2019, 09:08 AM   #38
kimmosto is offline kimmosto  Finland
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Quote:
Originally Posted by Juhazi View Post
Can you show simulation at 1m vs. 2.5m ?
Practical case is to capture measurement data at 1000 mm and simulate hor & ver planes on spherical surface, radius equals to typical listening distance e.g. at 2500 mm. I don't have measurement data captured at 2500 mm, and simulating directivity to 1000 mm is irrelevant. So my answer is No thanks.
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