Converting a 3-way passive speakers to active - they have dual woofers

[Music1969]

Hi,

If I were to convert Elac DFR52 3-way to active, how would I wire the 2 x woofers to a power amp?

Dealing with the tweeter and midrange driver is straight forward.

Is there anything tricky about wiring the 2 x woofers, to make sure the 2-channel power amp powers both woofers on each Left and Right speakers?

 

[dougi]

Probably the safest bet is to wire the same way as they are in the passive network. ie whether they are in series or parallel now. If they are two 4 ohm woofers now wired in series (8 ohm effective load), doing active in parallel will be a 2 ohm effective load! So spend some time working out the configuration and also determining or measuring what the impedance of the woofers are.

 

[ooheadsoo]

It would be best to determine the impedance response of the woofers to determine if you will wire them in parallel or in series. The wiring for the passive implementation will likely be taking into consideration the impedance of the mid and tweeter, which you no longer care about in your active configuration.

 

[Music1969]

Probably the safest bet is to wire the same way as they are in the passive network. ie whether they are in series or parallel now. If they are two 4 ohm woofers now wired in series (8 ohm effective load), doing active in parallel will be a 2 ohm effective load!

Thanks guys.

What is the downside in just proceeding with wiring the woofer in series? Regardless of how they are wired in passive crossover.

In practical terms, I can deal with 8 ohm effective load, i cannot deal with 2 ohm effective load LOL

 

[andreasmaaan]

Depending on how handy you are with electronics, you can build an impedance jig for very little cost by following schematics that can be easily found online. Alternatively, you can buy something like this device, which will allow you to measure the woofers' impedance via software.

The simplest alternative would be to check how the woofers are wired in the existing crossover, and to stick to that wiring.

Your main risk here is wiring low-impedance woofers in parallel and creating a too-low impedance load for your amps. So, if in doubt, wire them in series would be my advice.

 

[andreasmaaan]

What is the downside in just proceeding with wiring the woofer in series? Regardless of how they are wired in passive crossover.

The only downside would be if your amps are voltage-limited and therefore unable to drive the series-wired woofers to desired SPLs.

 

[ooheadsoo]

Agreed, wiring in series is surely safer than wiring in parallel, if you have no way to test. But, for example, if the woofers were 8 ohm woofers, you wouldn't necessarily want to wire them in series, as many amps will run out of voltage. Testing will be the most informed way to make a decision.

 

[Music1969]

Alternatively, you can buy something like this device, which will allow you to measure the woofers' impedance via software.

Thanks! Compatible with REW?

 

[andreasmaaan]

Thanks! Compatible with REW?

It uses its own software, but is very easy to use

 

[Music1969]

It uses its own software, but is very easy to use

Thanks again. I'll get it.