Bandpass Enclosure & Baffle Step

[69stingray]

Hello everyone. I was playing around with the Tang Bang 6.5" Neo Subwoofer in a bandpass enclosure (Unibox). I am curious to how baffle step plays into this type of enclosure.

I am guessing that most of the output is produced by the port and if the port is on the front baffle (pointing towards the listener), then the port acts as a driver and has the same baffle step? If the baffle is small enough, the raise in response should be outside the operating range, correct?

Therefore, the output from Unibox would be ~ 6 dB lower then predicted?

[Svante]

Originally posted by 69stingray
Hello everyone. I was playing around with the Tang Bang 6.5" Neo Subwoofer in a bandpass enclosure (Unibox). I am curious to how baffle step plays into this type of enclosure.

I am guessing that most of the output is produced by the port and if the port is on the front baffle (pointing towards the listener), then the port acts as a driver and has the same baffle step? If the baffle is small enough, the raise in response should be outside the operating range, correct?

Therefore, the output from Unibox would be ~ 6 dB lower then predicted?

Yes, the baffle step will affect the response just as if the vent was the driver. For the frquency response, this does not matter much, since the baffle step typically affects the response above ~200 Hz.

However as you say, if the software predicts the level in half space and neglects the baffle step, it will predict a level that is 6 dB too high. This is true not only for bandpass systems.

Now I don't have the parameters for your system, but using a another BP design and a baffle of 40 by 40 cm the difference could look like this with and without taking the baffle step into consideration:

[69stingray]

Thanks Svante, that is what I figured after I thought about it for a minute.

I was thinking bandpass would be an idea for the woofer in a 3-way to help simply the crossover since it has a natural roll-off. I guess you would still have to deal with port leakage issues though.