Whatever sounds best to you. Either way the impedance of the output transformer stage of the amp will be modifying the frequency response of your speaker in accordance with the impedance variation of the speaker with frequency. If you have some test data of your speaker impedance response with frequency you can have an idea of what sort of equalization will be achieved. ( Wherever speaker impedance is low you will get a reduced output and wherever the speaker impedance is high then you will get an accentuated output.) Since you are not seeking a flat response then it is best to go with whatever sounds best to your ears.
2 responses Add your response