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Multi-Way Conventional loudspeakers with crossovers

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Old 23rd July 2012, 11:12 PM   #41
Mark Kravchenko --- www.kravchenko-audio.com
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why would that be if the mic is on the floor?
Check your cited book on the effective range of a ground plane measurement, and the attendant tilt you have incorporated. Then do the math on the reflection path you have created by raising the baffle above the very surface you are trying to use as a ground plane.

You have incorporated some good ideas here, but the lift off of the floor is not one of them.

You may have in mind that you will be using these enclosures off of the floor, fine and well, but then you should be testing them in a much different manner. The important points are in chapter 5 page 71 on.

You have a great design idea, good enclosure ideas, and a fairly well thought out crossover. Measurement is not easy to get right I know from experience. It is indeed very easy to get wrong.
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Old 24th July 2012, 01:23 AM   #42
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His measurements are fine. They just show some reflections near the mic. Because of this some smoothing is needed. Page 63 of the book describes ground plane and he's done it right. It's just uncommon to see. And it needs the mic to be "flush" with the ground. Which it never can be.
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Old 26th July 2012, 11:11 AM   #43
Henkjan is offline Henkjan  Netherlands
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raising the LOT above the ground is also in dr Joe's book and is intended to get the correct baffle step in, placing a loudspeaker on the floor which would normally be on a stand would "create" a larger baffle that would not give the right response (as iirc is also shown in the book). next time either find a way to reduce the floor reflections or use 2 measurements (ground plane and normal gated) and "glue" them together (or just accept the measurement as it is, since with some smoothing the basic curve looks the same as is indicated in post #24 )
Click the image to open in full size.
which should be "good enough" for initial filter design
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Old 27th July 2012, 10:14 AM   #44
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Yes you have the correct idea. Some ground plane, and some near field stitched together. The use of gating alone in a very reverberant room will not get you a clean response. But you are perfectly correct in stating that it is enough for crossover work.

Still think they will sound great. Better by leaps and bounds what was available in the 70s and 80s.
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Old 27th July 2012, 03:56 PM   #45
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Sometimes smoothing will approximate nicely to what a properly gated measurement will provide, but a lot of the time it does not. Usually reflected high frequency data data will smooth nicely, the real trouble comes with smoothing out peaks in the 100-500Hz range, give or take. At high frequencies, as the wavelengths are short, you tend to get a reflection containing a spread of frequencies and it averages out nicely. At lower frequencies though you get modal room interaction and reflections such as floor bounce coming in and these do not tend to average out anywhere near as well.

Personally I like to use reasonably short gated far field measurements, combined with a near field measurement + bafflestep estimation. Usually the far field measurement extends low enough to capture all of the diffraction ripple and the start of bafflestep, with the simulated bafflestep, added to the near field measurement, taking over nicely to complete the picture. This obviously has its drawbacks, such as designs with semi floor loaded woofers, but that kind of thing really needs to be balanced in room, just as bafflstep does anyway.
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Old 23rd August 2012, 08:07 AM   #46
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Any updates on this interesting build????? please let us know
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Old 30th August 2012, 02:27 PM   #47
Henkjan is offline Henkjan  Netherlands
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no updates I was away on vacation and I'm waiting for the prints so I can build up the filter with the proper components, and then maybe do some final tweaking on the filter.
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Old 14th September 2012, 11:20 PM   #48
Henkjan is offline Henkjan  Netherlands
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a small tweak on the filter: I made the series resistance on the tweeter 3.3 in stead of 2.7ohm, reduces the tweeter level somewhat (1dB@10kHz) giving the mid a bit more presence, resulting in an even more livelike image.
Trio CSS - filter schema (20120913).png
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Old 21st October 2012, 03:39 PM   #49
Henkjan is offline Henkjan  Netherlands
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progress at last
(I was ill for almost a month (salmonella caught me), so more than happy to continue)

laag filter zit op de print.jpg

I have not been all quiet, during the days I felt well enough, I started with an amp to match these: a Hypex ncore. realy a great amp only disadvantage is that now I want to upgrade the rest of my set as well
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Old 21st October 2012, 06:02 PM   #50
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Sorry to hear you were ill Henkjan.

Happy to see you are still alive and kicking!
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