L-pad for 15ohm tweeter

[setiawan]

I'm looking to attenuate the tweeters in my 15 ohm Leak Sandwich speakers. I hear that the impedance of the L-pad should match the impedance of the driver, but I'm having some trouble finding a 15 ohm L-pad.

Would it be a problem if I just used a 16 ohm L-pad instead? If I'm not able to find a 15 ohm L-pad, is there anything I can substitute?

Thanks

 

[ThetaII]

There are quite a few L-Pad calculators on the net. Have you tried using those? Do you have an idea of how much it needs attenuating?

 

[setiawan]

I should have specified - I'm looking to use one of those variable L-pads so that I can adjust as necessary, since at this point I'm not entirely sure how much attenuating might be suitable (though I've seen at least one other source that found good results with 6dB).

Most of the ones I come across are 8 ohm, some 16 ohm, but none are 15 ohm it seems. I don't have a background in electrical engineering so I'm not quite sure what the implications of mismatching the impedance between the driver and the L-pad are, but I hear it's not a great idea.

 

[weltersys]

The actual impedance of a driver may vary from near it's DCR (direct current resistance, as measued with an ohm meter) to many times it's nominal impedance.
Properly designed crossovers such as those used in the Leaks take the impedance curve of the drivers into account when selecting components.

A 16 ohm variable L-pad should be close enough for your purpose if the tweeter is closer to 15 ohms than 8 ohms.

 

[Galu]

Here is a UK supplier of 16 ohm L pads: https://willys-hifi.com/products/l-pad-attenuator-50w-16-ohm-wirewound-volume-control

Note what the supplier says:

Perfect for restoring vintage models featuring L-Pads such as the classic AR 4x and many other 15-16 ohm models from the valve era.