Help on adding a L-Pad to a Crossover

[LowVoltage]

I have just finished building a 2nd order Linkwitz-Riley XO for an eight ohm woofer and a six ohm tweeter. The tweeter appears to be overly bright. They are both rated at 92 db SPL. I have used the formula to construct a fixed L-Pad with a 3 db attenuation. It’s still too bright. Without ordering variety of different resistors to construct different versions, is there a way to add a trim pot or use a standard variable 8 ohm L-Pad to achieve the same result?

Thanks Mike

 

[richie00boy]

L-pads seem easy for you guys over the pond to find. Just put the L-pad between the filter and tweeter, completely replacing your fixed attenuator. I wouldn't worry about using an 8 ohm L-pad on a 6 ohm driver if that's all you can find. Also you probably won't need anything much more than 10 watts so don't worry about that either.

 

[owdi]

I am tweaking the filter network for my 2 way, which also has an 8 ohm woofer and 6 ohm tweeter. Unless your 8ohm woofer is a midrange, or has a very large diaphram, the quoted 92db/watt sensitivity is a lie. Do you have a frequency response graph?

In my case, the quoted sensitivty for my 7" 8ohm woofer is 90db/watt. Manufacturers quote sensitivity on an infinite baffle, where the driver is radiating into half space. Unless you are mounting your woofer into a wall, subtract 4-6db from the quoted sensitivy. This is what you should be trying to match your tweeter to.

For a 3db lpad for a 6ohm tweeter you used a 1.75 and 14.5 ohm resistors. I recommend you purchase a 3 ohm and 6 ohm resistor, for 6db of attenuation. For tweaking, consider getting a bunch of 12ohm resistors, which you can wire in parallel to get a wide range of values.

Dan