Mini EQ (sorta) question.

[JoeBob]

We'll I was wondering if there was a way to build something that acted like a mini EQ, let me elaborate. I wan't to be able to turn down my mids, or my woofers, or my tweeters, or turn them up. I don't really know how to do this, I've heard someone say that you can use a potentiometer with horn tweeters, but I do not know if this is possible with an active crossover (wouldn't it change the resistance the xover sees?) or for other drivers (like mids and woofers). Or maybe just make a 3-band EQ for the frequencies where my crossover points are? I dunno I'd like to be able to do it, but if it just isn't possible (although building a small EQ shouldn't be to hard, right?) I guess I'll steal an EQ from one of my other systems

[Ignite]

You could build an EQ and put it between your line level input and amplifier that was designed for your xover.

You could put pots on all the drivers with the right impedance. Though this only allows you to turn them down, not up.

You could bi-amp or tri-amp with an active crossover, which would yield the best results.

[JoeBob]

What I'd like to do is got the way of pots on the drivers, just the mids and tweeters are important, I want to bring them down to the volume of the woofers. Do I put one on each driver? Or one for all the mids and one for all the tweeters? This would be between the crossover and the drivers, right? Also what would be the "correct impedence"? Wouldn't adding a pot change the overall resistance the xover sees and therefore change the crossover frequency? Sorry for all the questions, but you're the only one that answered...

[Samuel Jayaraj]

Joe,

If you are only seeking to equalize the SPLs of your drivers, driven by a single amplifier, per channel and passively crossed over, you could use appropriately rated resistors to attenuate the mids and highs. These resistors can come between the relevant arm of the passive crossover and the respective drivers.

If you are seeking to relatively change the levels of a particular frequency spectrum, go in for a parametric equaliser (3 band or so). You'll be able to sweep the frequency and set the desirably Centre Frequency, Q factor and Amplitude.

Could you kindly make yourself a little clearer as to what is the problem you are facing or what is the result you are trying to achieve?

[JoeBob]

Ya, sorry for not being very clear. What I want to do is to equalise th SPLs of the drivers. But I don't want to use a fixed resistor because I'm not sure what the SPL of some of my drivers. So I was thinking of using a pot if possible, so that I can manually set it. Hope that helps...

[Samuel Jayaraj]

For setting up and initial tests, you could use pots of 3 or 5 watt ratings. Don't play at too loud levels. When you have determined the levels, you would have to measure the actual resistance of the pot settings and replace with higher wattage fixed resistors. An audio generator/test tones and an SPL(Sound Pressure Level) meter would be useful for this. If you don't have access to these, go by ear.

[Æ]

Not pots. One L-pad for each midrange and tweeter.
Try this site for a quick description
http://www.marvac.com/funpages/l_pad.htm

[JoeBob]

I never thought of testing it and then using fixed resistors. And as for the SPL meter, I'm sure I could get ahold of one. But the L-Pad looks like it would suite me best. But the site says "An L-Pad is used when direct control of the volume level of an individual 8 ohm speaker is desired", so would I use one for each mid, or one to control all the mids at once?

[Æ]

They look like a potentiometer, but function differently. For maximum control/adjustment, use an individual L-pad for each seperate midrange and each seperate tweeter. Radio Shack sells some.

[JoeBob]

Thanks, I'll look into them soon...