Anikun07's SLA Builds

[Bill Fitzmaurice]

I checked the total resistance across the woofers (14 ohm across a single) and 9.x-ohms across the set. The tweeters (13-ohms across a single) had a total of about 13-ohms. So these sound good to me. The total resistance of the cab, across the terminals, is about 10-ohms. If there's something wrong, it has to be the crossover.

Resistance is about 0.7 x impedance, so the woofers are about 13 ohms, not considering the impedance rise at the crossover frequency, which probably takes it up to 18 ohms as far as the low pas filter calculation is concerned. The tweeters are about 18 ohms. The resistance of the cab should be the same as that of the woofers, since the DC that the meter uses to measure resistance does not pass though the capacitors of the high pass filter.
If you configured your crossover component values for 9.3 and 5.3 they're AFU. And you're losing a lot of sensitivity having your drivers wired for such high impedances.

[anikun07]

You got it, Bill! I double checked the XO and it didn't make sense. I guess that's what I get for not taking my time and figuring it out on my own and using someone else pictures. Well I just finished testing and at 3500 Hz I can hear that the woofers are louder than the tweeters and at 4500 Hz they seem pretty close in volume, but at 4500 Hz the tweeters are louder than the woofers. Tomorrow the other two cabs will get their XOs redone. I'm looking forward to it! My two replacement woofers will also arrive tomorrow. Yay!

[Bill Fitzmaurice]

Finding the crossover frequency isn't difficult. Measure the AC voltage at the drivers. With a constant voltage sine wave input the voltage measured post filter will be fairly constant below the filter knee of a low pass filter, or above the filter knee of a high pass filter. When you sweep the signal frequency the corner frequency will be pretty obvious.
Also, your missing drivers will affect the impedance load, and changing the impedance changes the crossover transfer function.

[anikun07]

Thanks, Bill. I used my completed speaker for this first correction precisely because I wanted all drivers accounted for. I was wondering what capacitors and inductors do. Capacitors hold a charge then release it, right? Or is that what diodes do? I don't know what inductors do, step up or step down voltage? Even though air core coils don't have a magnet? Electronics is a subject I'm not as knowledgeable as I'd like to be.

[Bill Fitzmaurice]

Thanks, Bill. I used my completed speaker for this first correction precisely because I wanted all drivers accounted for. I was wondering what capacitors and inductors do. Capacitors hold a charge then release it, right? Or is that what diodes do? I don't know what inductors do, step up or step down voltage? Even though air core coils don't have a magnet? Electronics is a subject I'm not as knowledgeable as I'd like to be.

http://www.bcae1.com/xoorder.htm

[anikun07]

Thanks, good link.