Crossover +/- 3db

On my passive crossover for my components there is a 'jumper' with pegs that correspond to -3db 0db +3db.  Is this some sort of boost?  I'm not exactly sure what it does.

Thanks!

You could look at it as a booster the same way you look at a glass half full of water.  It's two available degrees of attenuation and the third connection leaves it as an unadulterated response.  The setting "+3" db is with no attenuation and uses the natural higher sensitivity of the tweeter (compared to the mids) causing the 3 db increase.  The next setting, the "0", is 3 db down from that, which is normally the best sensitivity match to the mids.  The third setting, "-3db", is 6 db down from natural and 3 db down from the most even sensitiviy match.  One way or another, depending on the setup, your ears, the quality of the rest of the system, etc,, it will sound better to you than the other ways.

Personally, I find it difficult to make up my mind about one way or another with those things.  High freqs are difficult for me anyway, and there's the fact that a person quickly gets used to whatever he's listening to at the moment.  So it's hard to do a good A/B comparison.  Try "0" to match the tweeter most closely to the sensitiviy of the mids.  If after listening for awhile using several favorite sources, you find it not what you expect, try one of the other two settings.  Use the same setting on both crossovers for good system balance.

Nice info!  Right now I have it set on 0.  I will try the +3 for a while and see how it sounds.  The +3 is with no attenuation?  I assumed that 0 would have this effect, that is why I have left it on that. 

I appreciate it!

No problem.  Take a look sometime at speakers sold individually.  Look at the sensitivity of the average tweeter, about 92 db 1 watt/ 1 meter.  Then look at a woofer.  You'll rarely see one with that high of a sensitivity.  It's normal when building crossovers to add some attenuation to the tweeter to bring the two drivers more in line with each other in sensitivity.  Adjustments are made by the builder the same way you are making adjustments on your crossover...testing the response and listening.

The "0" in this case is not a number regarding attenuation.  It is rather a reference point which indicates more or less an even match in sensitivity with the mid.  It makes sense to try it first, and it's in the middle.