[Devros]

Could someone help me with a headphone limiter. I need one to put in between my headphones and my metal detector. I don't need anything fancy, but would like to be able to use a pot and make it variable. I'm sure this can be done, I have looked and either don't understand it, or it's just not what I'm looking for. So if there is someplace where it is simply put and laid out could you point me in the right direction, or post a plan here please. Thanks for your time.

 

[roggom]

Well, if you are looking for a cheap and easy solution, get the Koss inline volume control.

Koss VC 20 - Volume control

 

[Devros]

I need it so that the really high hits don't blow my ears out. So I need it to limit the high hits. That's why the limiter, and not a volume control.

 

[Uncle Erik]

You could try building a low pass filter that will remove the highs.

 

[Fred_fred2004]

If you use 2 diodes back to back across each channel they work as a voltage limiter, they only conduct when the voltage goes over .6 volts, very easy and very cheap

 

[Devros]

Oh ok, I will give that a try, so say if I had two 1N914 across each channel it would limit however much of the voltage was trying to cross over, then If I used a different size that limit would change. I get that, and it's easy, so one more question how to I figure out how much it is limiting when using the diodes, I'm sure that there is a formula someplace. thanks guys.

The first idea that I had about be variable that can be done right. without a power source.

 

[Fred_fred2004]

The silicon diodes won't conduct until they have over .6 volts across them so the size and type won't make any difference, Germanium diodes conduct at 0.2 volts. The two diodes method was used in telephone handsets to stop the loud pops and bangs of the old mechanical system (god I feel old now)

 

[Juaquin]

The diodes are good but they aren't selective. If you only want to attenuate the high frequencies, just build a low pass filter.

 

[TimmyMac]

I don't think it's high frequency he wants to limit, but high volume. Read his post...

2 diode thing would seem to work.

 

[Juaquin]

Quote:

Originally Posted by Devros /img/forum/go_quote.gif I need it so that the really high hits don't blow my ears out. So I need it to limit the high hits. That's why the limiter, and not a volume control.

I took this as high frequencies (as did Uncle Erik, it seems) but I suppose it could also mean leveling volume so there isn't a lot of range, in which case the diodes are a pretty simple solution.

 

[Devros]

Yes I do want the high volume limit. Thanks guys for helping me out here. I will try out the diodes today and see how they work. Thanks for again for the simple solution, I was just simply trying to make it to hard.

 

[linuxworks]

variable compressor?

set the threshold so that it only compresses (limits) when it hits the level 'too loud'.

there used to be a good one that was cheap, years ago. google 'really nice compressor' (RNC). I have one that I never use and bought when it first came out, to play around with (I was toying with pro audio back then).

...a lot nicer than back to back diodes

 

[Devros]

WOW! that's pretty complex for a simple metal detector limiter, LOL. That thing is cool none the less. I don't think I would want to carry that around with me though. Thanks for your help.

 

[linuxworks]

doh! didn't see the METAL DETECTOR part. lol. here, I'm reading a post on a hi-fi site assuming you had hi-fi in mind. oh well

in case you DO want a quality limiter, a compressor (pro audio gear) does that.

...btw, headfi is usually 'high fi' and yet you want 'low fi' so you confused the hell outta me

 

[FourierMakesFunk]

Only letting volume above a certain value is a gate, and a low pass filter may work if that's your problem, but if you want to make a true limiter (which prevents the audio from getting above a certain level not by muting it above that level, but by cutting the gain):

HeadWize - Project: Designing A Limiter For Headphone Amplifiers (A HeadWize Design Paper)

-OR-

Fast Audio Peak Limiter
Audio limiter circuit schematic
http://www.repeater-builder.com/proj...er/limiter.gif