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High Simulated Impedance - Concerned?
High Simulated Impedance - Concerned?
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Old 1st November 2019, 02:04 PM   #11
sangram is offline sangram  India
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Originally Posted by prolow View Post
Thanks for the help, swapped polarity and sloped FR.
Feedback welcome.
I doubt that fixed the problem though.

There are three main issues I can see:

1. that 10mH inductor in the mid circuit looks very wrong for that crossover frequency. There's still no series resistor, which means you're trying to use reactive components for achieving padding - a bad strategy overall wrt system impedance. A bit of a peak in the middle of the crossover region is not a problem (for impedance, not FR) for most any kind of amplifier except maybe some exotic current feedback types, where you would anyway look for high target impedance and then use a zobel on the whole system.

2. the mid is breaking up badly at the top end, it desperately needs a tweeter above 8k. If I were using that unit, I'd cross it at 5 k just looking at the datasheet - which I should have done earlier.

3. I wouldn't cross over anything with Z-offsets in the 400-1k range at all. This means only coaxials can be crossed that low, and I've yet to meet one that can. You will definitely get lobing issues off-axis, and bang in the middle of the vocal range.
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Old 2nd November 2019, 04:15 AM   #12
PRR is online now PRR  United States
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Isn't there a Speakers section for such threads?

> load peaking at 28 Ohm and dipping to 2.8 Ohms, outside the 4-16 Ohm range the amp is rated for.

The 28r is Not A Problem. ALL speakers do this. Any audio loudspeaker amp must tolerate it. (It isn't rated for Power in 28r, but we don't need Power when the speaker is resonating.)

<3r for two 8r speakers suggests a b-r-o-a-d overlap where both are working. There are times when this is valid. But the Ten can work to 1kHz pretty well, and at high power the Three may be stressed working to 300hZ. I'd pick the crossover nearer 800Hz to 1.2kHz. And I'd lean to a simple first-order crossover. Maybe 1.5H and 25uFd.

Hi-Fi convention says a Three won't "fill the room" at 20KHz (if it even gets there). We go to a One-Inch tweeter above 2kHz-6kHz so the small source spreads the sound. But IMHO a good Three with a small sofa on-axis can be a fine system. I had a "wide range Twelve" and added a Three, it was quite nice in my chair. It didn't throw highs all around to get lost or echo from kitchen and hallway, very clear.
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Old 5th November 2019, 04:26 AM   #13
prolow is offline prolow  United States
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have a series of alternate driver and crossover designs, would appreciate feedback on, where should I post that?
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Old 5th November 2019, 10:41 PM   #14
PRR is online now PRR  United States
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Loudspeakers * Multi-Way * Conventional loudspeakers with crossovers
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