This is an effect that will adjust the midrange frequencies, both in terms of midpoint and level. "Shifting" them up or down, players can dial in a wide variety of tones more quickly than setting each individual frequency.

What is Pre/post line out with XLR?

Players can use this to bypass the internal EQ and power amp of their rig, sending a balanced signal to a mixing console. By running a signal directly from the amplifier into the mixing console, clarity (and especially lower frequencies) are not lost to post-speaker milking.

What is a Limiter?

The limiter is provided to protect your amp and your speakers. It limits the amount of power and distortion going to your speakers. When the amplifier reaches dangerous levels, it will put a ceiling on the power it provides. When the limiter light comes on, your volume will have a noticeable lack of "spike".

Why do some amplifiers have internal bracing?

Internal bracing provides cabinets additional support and rigidity. This helps keep the cabinets tight providing better sound and a much longer life for your rig.

What does a crossover do?

A crossover separates low frequencies from high frequencies. When used in an amplifier, the crossover routes the low frequencies to the larger speaker and the higher frequencies to a tweeter or horn. The results produce a full, broad range from the cabinet.

What does an external speaker jack do for me? Could I run a 4x10 cabinet with my BFX15?

Actually, you could, although you would no longer be able to hear any sound coming from your original BFX15 cabinet. The external speaker jack automatically cuts off the original speaker, in case of different Ohms ratings for different speaker cabinets.

What does the impedance matter?

Matching the impedance on your amplifier (head) and speaker cabinet is very important. The impedance is basically the resistance of the speakers. If your amplifier is trying to provide a large amount of power to speakers but can't because the resistance is too high---chances are it will burn itself out rather quickly. For instructions on how to connect extension cabinets, external speakers, etc... please consult your owner's manual or contact a certified Service Technician.

How do I know if I want an extension cab?

An extension cabinet can be a great way to extend your volume and tone, plus it is usually a lot cheaper than buying another amp. If you decide to use an extension cabinet, remember to make sure the resistance is matched correctly.