Bass reflex used as active BSC?

[edjosh23]

I was wondering if a rear firing port could be used as active bsc. If the box is designed a bit larger than it should be, there would be a sight hump at the tuning frequency. If there is a 3db hump coming from the back of the enclosure, could this make up for a baffle loss?

Thanks,

Josh

[joe carrow]

Keep in mind that bass (within the range of what comes from a port) is not directional enough to care where on the enclosure it is coming from. The port can be pointing down, left, right, or behind or on top- and it will really only care about its point in space and how many fractions of a wavelength it is from nearby boundaries.

It might not be proper baffle step compensation, but the end result of the baffle step is quiet bass (with respect to the rest of the system), so you're definitely able to make it less of a problem by designing an enclosure with more pronounced bass.

You'll need to pay attention to what frequency your baffle step starts- cabinet width should tell you this, and how pronounced the effect is before room gain comes into play- determined by room dimensions.

Bottom line- I'd recommend an alignment with a broad raise of level starting at a frequency at something that's probably well above the tuning frequency, and without a very sharp peak anywhere near resonance.

[owdi]

Not a good idea. The peak from tuning high in a big box is much narrower than the gradual (about 2db/octave) baffle step.

A better solution is a second driver directly opposite the front driver. No baffle step compensation to worry about, and the drivers will cancel out vibrations in your enclosure.

Dan