I have finally got my sub, amp and power supply but I have an issue that I need to limit my sub for anything less than 16hz because the drivers are going beyond excursion

Any idea how I would start to make one or better yet one I can buy off the shelf, ideally an adjustable HPF?

Thanks

Craig

1 - 20 of 23 Posts

Could easily put a capacitor on the input.

+1. I have done this before with accurate results.

Could easily put a capacitor on the input.

If a 1st-order filter is all you need, this is by far the simplest and cheapest solution.

This is interesting. I'm also looking for getting a minidsp, but this could be a short term solution. looking forward for more details+1. I have done this before with accurate results.

If a 1st-order filter is all you need, this is by far the simplest and cheapest solution.

Using the formula for HPF and a spreadsheet you get the following results for a 16 Hz cutoff and assuming your amp's input impedance is 47 kΩ or greater, then the combined impedance of R1 and R_amp (R2) is 8.25kΩ

Then using the info from here: http://www.t-linespeakers.org/tech/filters/passiveHLxo.html you get R1 as 10 kΩ and C1 as 1.2 micro Farad

-Bill

Then using the info from here: http://www.t-linespeakers.org/tech/filters/passiveHLxo.html you get R1 as 10 kΩ and C1 as 1.2 micro Farad

-Bill

The amp is dedicated only to the subwoofer.

As above if a 1.2Micro farad will do, how would I connect it, across the lines or in series?

Thanks for the help

Craig

The setup would be: Sub Output from receiver goes into the capacitor with the resistor after it connected to earth. (As per the picture, the sub out is on the left and the power amp input is on the right.)

-Bill.

What resistor would I need and where on the line would I place it, across the positive and negative lines?

Thanks again

Craig

Thank you, is it a ceramic or tin top capacitor I need?

http://www.parts-express.com/pe/showdetl.cfm?partnumber=027-722

in parallel with this:

http://www.parts-express.com/pe/showdetl.cfm?partnumber=027-714

And a resistor like this:

http://www.parts-express.com/pe/showdetl.cfm?partnumber=002-10K

Remember, we are dealing with line-level inputs here. A small smd 50V cap will do the trick, maybe even 25V depending on his source. NOTE: I haven't calculated the cap value needed for a typical 47kohm input impedance amp, so I'm not sure if a value close to needed is even available in smd form.

I also agree that the resistor is unnecessary, but since he isn't sure what the impedance is, going with the resistor will reduce the error.

If it was me, I'd do it your way. Or Fusseli's way. But for someone who doesn't really know what he's doing: the most recent suggested components will be just fine.

However, not knowing the exact impedance it is easier to add the 10 kΩ resistor with the 1.2 uF cap to guarantee you get the desired results.

If you have ways of measuring it then I would suggest trying the .21 alone as per above.

How about you tell us what amplifier you are using, and maybe we can figure out a simpler filter for you.

Thank you.

How about you tell us what amplifier you are using, and maybe we can figure out a simpler filter for you.

I did give it a try and it didn't work correctly the freq drop was WAY high.

The amp is an onkyo nr1007 and the sub amp is actually a modified car amp to work on mains power using a PC psu

Craig

1 - 20 of 23 Posts

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