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Looking to cross LR4 @ 4khz and wanting a bit of vertical directivity. Thoughts?
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I used the amt2-4 in my MidNite Magics build crossed at about 3.5k. I did not measure vertical directivity but can tell you the horizontal was beyond my expectation. The z axis with the surface mounted tweeter was in the .009 range. They also well exceeded my expectations. -
That's encouraging. Have you used or heard the Neo CD 1.0 at all? I've used the 2.0 a number of years ago and liked it. I've heard some of the new AMT's at RMAF, Often impressive with a liveliness, but sometimes had a sort of buzz. I experienced this when designing a speaker for a friend and had to remove the screen that covered the diaphragm so the buzzing would stop.Comment
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Ive heard the Neo 1 but it has been some time ago. So I would hesitate to make a direct comparison. It sounded good with no apparent issues that I can remember. No idea where it was crossed at though.
As far as buzzing issues with the AMT, I've not heard anything of the sort and I tested mine at 90+db at 1m. With a 4th order electrical filter, they are crossed very steep. I used this filter mainly because of the phase alignment. It crossed fine with a 3rd order for a flat response. The last coil just brought in an additional level of "smoothness" to the integration between the drivers. I use an Adcom GFA555 (about 250w/ch) and they have had no issues taking power from it with the volume control over the halfway mark.Comment
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I haven't measured the vertical dispersion of my cd1.0, but at listening distance the vertical off axis sounds (to me) just fine when standing. I probably spend more time listening while walking around doing things than sitting in the sweet spot. I have not heard the amt to compare it. Mine is crossed at 5k, 3rd order electrical. No buzzing on my smaller amt, sounds like it was a defect. also, I would be cautious in removing the top screen area of an amt as I believe it is part of the magnetic circuit.Last edited by dynamo; 11-27-2016, 01:38 PM.Comment
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One of the benefits of the Neo CD1.0 is that it does have significantly better vertical dispersion than most ribbon tweeters (presumably due to its shorter ribbon length). I cannot compare it to the AMT2-4 but I've used it several times, and Paul Carmody used it in his Speedsters. In my canTiLena it was crossed at 4.8 kHz to a Morel MDM55, and my recommendation would be to not cross it below 4 kHz (which is where Carmody crossed it IIRC).
PaulComment
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I'm actually looking for some vertical directivity. How much I don't know yet, I have to model the polars on the woofers and mids. The design criteria are very wide horizontal dispersion and *somewhat* limited vertically.Comment
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Sounds like you just described the cd1.0 exactly. The ribbon is only about 1/4 to 3/8" wide so horizontal dispersion is incredible, while vertical is limited somewhat but not locked in like a ribbon several inches long would be.Originally posted by augerpro View PostComment
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In looking at factory graphs it looks like horizontally the cd1.0 at 45deg is within about 6db of 0 at 15k and 8db at 20k, where the amt is about 13db at both points. Both are good horizontally but the fountek is better. Fountek also publishes vertical measurements.
As a whole the amt starts rolling off sooner than the fountek as well. I'm sure the amt is nice, but I feel the cd1.0 is a good value for a true ribbon.Comment
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From a measurement perspective the Fountek is the better driver for your intended purpose IF you can cross that high? I'm suspecting a tightly spaced MTM with small mids is where you're headed with this?Comment
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Yeah very small mids. At this point it's all conceptual since I can't do any wood work atm.Comment
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Is there some reason you're not considering the Dayton PTMini-6?Comment
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