TOPIC:

Hello!

I am about to build a subwoofer, and I want to use the Peerless XXLS-P835016 Chassis. In its datasheet the power rating is stated as "Rated Noise Power (IEC 2685 18.1) = 100W, Test Spectrum Bandwidth 20 - 4kHz, 12dB/ Oct.

How can I adjust the limiter correctly, so I can effectively protect the speaker, but dont lose power?

Thank you very much for your help!

Regards,

Florian Mayerhoffer

Florian,

You could see some online information on setting up a limiter (might be more detailed) but there are few ways:
- With your ears/SPL meter, i.e. if you reach max threshold where you feel your driver is already too loud, then use that as your reference and setup the comp/lim to start attenuating from that level.
- A bit more math would be to use a voltmeter. Would be more trouble than you need. Option1 above will work well. You'll start to see/ear distortion of your driver as you get close to his max.

Are you planning to use the PWR-ICE125 in bridged mode?

Hello,

thanks for your answer! Yes I would use it in bridged mode - is there a reason I shouldnt? 125W @ 4Ohm is a bit little, 450W though a bit much... I will definitely have to use the limiter.

Okay, by ears.... seems a bit dangerous to me but well, I have no better idea anyhow. What if I dont hear the limit approaching? Because it's approaching gradually e.g. - Or is it definitely not a slow developing process, is it actually a process where all of sudden you hear "here's the limit"? Never done this before...
A very important question: What signal shall I use for that? Pink noise? Or a sine at 20Hz? If pink noise: Is there a difference between low pass filtered or not low pass filtered signal?

What do you actually adjust/ limit, is it the input voltage of the amp? Or actually its power output?

Thanks for your advice!

Florian

Florian,

- By ears will actually quickly become obvious to the trained ears as you'll hear rattling/distortion level rising. It's not dangerous..
- If you want to do accurate, using a multimeter would be the way. Sinewave would be the way. There are quite few online resources that would be a lot more accurate, Did you google that topic? Might want to do it just in case... Here is a basic step I guess:

- Connect a multi-meter (set to AC volts) to the binding posts without load.
- Turn off limiter, Send a sinewave tone signal e.g. 100HZ at close to the max level of your source (i.e. read specs of your audio source feeding the PWR-ICE). Lower the input level to have an idea of how much level you need to lower your output. (i.e. dB)
- Turn on the limiter, put the input level back to 0dB with a fast attack and a fast release, then adjust the actual voltage by using the threshold value.

DevTeam

Hi,

thanks. I have read now two online sources about how to adjust a limiter, and together with that what you wrote I feel a bit more comfortable now.

Why 100Hz? Why not, let' say 28Hz, the port's frequency, or even lower, where the maximum of excursion will be reached sooner due to less resistance? (I will use a ported design). Will 100Hz sooner reach the limit due to overheating the coil?

So if I understood it right, the limiter of the PWR-ICE 125 limits the VOLTAGE and not the output power, right? Is the limiter hopefully after the masterlevel (knob) of the module? So it doesnt matter if I take a high output of my source and a low input of the module (knob) - or a low output of my source and a high input of the module (knob)? As the limiter limits the total input voltage just right before the power amp?

Thank you, regards,

Florian