BillFitzmaurice.info

Just need a sanity check here to make sure i'm doing this correctly. Now that I have the XTI2000, i'd like to use the built in limiter. I read a ton of other posts so, i'm pretty sure this is correct but, please double check my work.

I'm running 2 - Dual Loaded T24s with BP102s @ 8 Ohms Parallel. One dual loaded sub per side. This gives me 4 ohms or resistance at the amp. I didn't see in the other posts where the ohms were taken into consideration though when setting the limiter, just the output voltage at the output was all that mattered. Is that correct?

I'm also running the appropriate crossover settings for the sub per the plans.

The plans say to limit the BP102s to a max of 35v. I'm using a craftsman True RMS meter set on AC voltage.

Here was my step by step:

1. Unplug Subs from XTI2000
2. Set True RMS Multimeter to AC and run to CH1.
3. Crank Amp to Max.
4. Generate a 100hz (Also tested with a 75hz) tone with YMEC Realtime Analyzer set to "Sinusoidal".
5. Increase Mixer till reading was over 60 volts
6. Engage limiter on XTI2000 till the voltage is under 35v. (I got it to reliably limit to 31.x volts)
7. Mirror limiter settings for CH2.
8. I then tested multiple volumes / frequency settings. No matter how loud the signal was driven into the amp, the output never crossed over 31 to 34 volts.

Does this look ok? Am I missing anything here? I'll tell you what, if I've done this correct, I've been running those subs way under potential. There is no way I was ever pushing them as hard as they go to hit that 31 volt limit they are set to now...

Thanks for the input!

#3 You need your mixer gains set to their maximum. Do a search for "setting gain structure".

#4 Lower the tone frequency to ~70Hz if you are high-passing the subs at 40-45Hz per the plans.

Other than that, it looks good.

Thanks!

#3 I did go back with a 75hz test the second time around. It looked good, kept the same voltage.

#4 When running the second test, I had the mixer all the way up. Seemed that with the mixer all the way up or 75%, it still held the 31v limit. But either way, I had everything at max and it would not budge over the limit. That should be ok, correct?

+1

All limiting does is prevent over voltage from reaching your driver.

I checked again tonight and it's holding steady at 31-32 volts. Next test I played some music, cranked it up and watched the meter. Seems like it held the voltage down mostly but saw it peak 38-40v... is this because the XTI is not a brickwall limiter?

Am I ok to leave it here, or should I back down more?

Interesting! I would have thought the limiter would do better than let 25% more peak voltage through.

Your amp is a little bit overkill for the amount of power you can actually use. You could run the whole lot off one channel at nominal 8 ohms if you wired each cabs dual drivers in series.

Do you guys think I should apply more limiting? I figured since I could not cross the voltage with the generated signal, it would not cross in any situation?

Bryson wrote:I checked again tonight and it's holding steady at 31-32 volts. Next test I played some music, cranked it up and watched the meter. Seems like it held the voltage down mostly but saw it peak 38-40v... is this because the XTI is not a brickwall limiter?

Am I ok to leave it here, or should I back down more?

You are correct onboard limiter is not brickwall. IMO drop it down enough to split the difference and use common sense when running the system.
Basically stay out of the red anywhere in the signal chain. If you need more oooomph add more boxes.

Maybe picking up a brickwall limiter makes some sense now.