As mentioned by others, this is normal behavior of a woofer with low frequency low-pass filter. The impedance resonance peak of the woofer in the sealed cabinet and the the crossover interact in kind of a "resonant circuit".My question is: Is it possible for a crossover circuit to create a peak that is higher than the raw driver response?

As an example. If someone buys an 8 Ohm woofer and thinks that this woofer has constant 8 Ohm, that someone might use a online tool to calculate a LR 4th order low-pass filter for this woofer in a sealed box***.

It might look like this (it's a half room, 2pi simulation, but it doesn't matter in this case). In pink is the LR 4th order @150Hz low-pass filter target function. In red is the FR for the calculated XO filter (I did only a quick approximation) and in blue is the FR of the driver without XO:

It's perfect, but in reality (as everyone knows) the impedance isn't constant.

So when using the real woofer with its impedance peak at the resonance frequency of the sealed box and the filter interact with each other.

In green is the impedance of the low-pass filter interacting with the constant 8 Ohm. In black is the impedance of the low-pass filter interacting with the "real" impedance of the sealed woofer:

Around 82Hz we get an impedance minimum, which will influence the frequency response of the speaker.

In reality we end up with a FR with a peak around 82Hz (which surpasses the woofer SPL without XO) shown in red:

In the same way (low-pass filter and sealed woofer resonance interact with each other), the frequency response peak arises in your measurement of the AV123 woofer with XO compared to the FR measurement without XO.

*** Used a simulation of two GR Research M165-16 woofer with 15L sealed volume for each woofer.

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