How to change ohm value of speaker?

[cT equals piD]

Ohm's law can't be defeated

This is basically off-topic as it doesn't relate to a practical solution to changing an 8 Ohm driver to 4 Ohm.

But you CAN connect an 8 ohm driver to an amp that has -4 Ohm source impedance and thus the amp and driver will behave as if the driver was 4 Ohm.

If I remember correctly, an amp can have negative source impedance by virtue of positive feedback.

ACE BASS, which I don't understand, makes use of an amp with negative source impedance.

Don't ask me to explain in detail how all of this works.

For what it's worth,
Pete

 

[AllenB]

Both of these options will work but they require skill, particularly using a positive feedback amp. I doubt I'd choose to use this method for this kind of problem myself let alone recommend it to someone that may never have heard of it.

The facts of the matter at hand are that the amp won't be damaged and the power difference is not that significant. Due to the way we hear things the power needs to be viewed in a logarithmic way. 20W is not much differrent to 10W. Just try it and see.

If you need more power then the most practical solution will be another amp or speaker.

 

[Scarecrow77]

you could wire another 8ohm speaker directly off the one you already have, both speakers will return 4ohms

 

[KMossman]

adding a resistor will change the impedance the amp sees but not increase power as the resistor will be absorbing its share

Choices;

1 - re-wire speaker
2 - bridge amps
3 - transformer (bizarre but valid)
4 - put 2 such speakers in //

 

[phivates]

Pad down the tweeter to match the mid, then upgrade your amp if needed. Most amps are happier with the 8 ohm load, which is just a nominal value anyway. Love Scanspeak, BTW.