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Multi-Way Conventional loudspeakers with crossovers

What is the polar response of "L-frame" OB speakers
What is the polar response of "L-frame" OB speakers
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Old 6th October 2020, 11:29 AM   #1
scottjoplin is offline scottjoplin  Wales
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Default What is the polar response of "L-frame" OB speakers

Open Baffle Basics pt.3 - YouTube

The video above explains how a flat response is achieved by acoustic solutions. However he doesn't mention the effect on the polar response of this method. Has anyone tried this and/or done measurements?
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Old 6th October 2020, 07:09 PM   #2
classicalfan is offline classicalfan  United States
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Glad you brought this up. I've been wondering about it as well.

Might be better to post the same question over at audiocircle.com where most of the GR Research discussion takes place. I'm not sure if Danny even looks at this forum.
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Old 6th October 2020, 08:04 PM   #3
scottjoplin is offline scottjoplin  Wales
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Thanks for the suggestion.
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Old 6th October 2020, 08:23 PM   #4
classicalfan is offline classicalfan  United States
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I would do it for you myself, but I've been banned over there for too many challenges to the cable manufacturers for all of their snake oil posts.

So I can still read the forum, but I'm not allow to post anymore.

Last edited by classicalfan; 6th October 2020 at 08:28 PM.
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Old 6th October 2020, 08:27 PM   #5
scottjoplin is offline scottjoplin  Wales
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Thanks for the offer, yes, I recall you saying. I've just joined. Logically the answer is probably quite straight forward, the response will be skewed accordingly I would imagine. It would be interesting to see measurements though.
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Old 6th October 2020, 10:48 PM   #6
classicalfan is offline classicalfan  United States
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Iím expecting that there will be some sort of tradeoff.

While adding wings to an OB may help to flatten the FR curve it almost certainly has to affect the polar response. Particularly if the wings are significantly unequal in length as they are in these GR Research designs

So now you are not going to get equal cancellation for lower frequencies on both sides of the baffle as you do without wings. That means a certain amount of low frequency energy will be emitted to the side and consequently reflect off the side walls. How that translates into room response is the now the question.

Notice that some very well respected OB speakers do not even attempt to use this approach. Notably Spatial Audio Lab speakers have no wings at all. Nor do planars like Magnepan.
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Old 6th October 2020, 11:38 PM   #7
AllenB is offline AllenB  Australia
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What is the polar response of "L-frame" OB speakers
Done at four different frequencies, and perhaps seeing a pattern?
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Old 7th October 2020, 12:09 AM   #8
classicalfan is offline classicalfan  United States
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But this is quite different from what scottjoplin brought up to begin with. He was asking about asymmetrical L configurations. This is a symmetrical U box. Would not expect the same acoustic patterns from them both.
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Old 7th October 2020, 01:06 AM   #9
AllenB is offline AllenB  Australia
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What is the polar response of "L-frame" OB speakers
Indeed. Ok, this is a plain L.

It seems to follow the idea that if you try to deal with a directional issue like diffraction only focussing on one direction, you'll pay for it on other axes.

It's my view that a design should start out as symmetrical by default, unless/until proven otherwise, and notwithstanding a need to produce asymmetrical directivity as that's a different matter.
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Old 7th October 2020, 03:23 AM   #10
classicalfan is offline classicalfan  United States
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In the video that Scott references in the first post the main focus is on frequency response. In fact, polar response is not not dealt with at all in it.

So the real question here is whether optimizing one of the performance characteristics compromises a different one. There might not be a single 'right' answer, and if that's true then an understanding of the trade-offs would be valuable to have.
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