every box will have good and bad points from where it will sound best to how big it is. A band-pass box is made so that it will let a band of freqs play a little louder then the rest. This gain in sound in those frequencies is often done at a loss to the others so it is important to make sure you get it right as there is not much room to tune them afterwards. I like sealed boxes because they are smaller(easier to hide), and with different tuning/eq systems you can make the sealed box sound just like the band-pass if you want.

 

To be clear... 4th and 6th order enclosures are NOT efficient.

 

I pretty sure (having been in the Car Audio industry for 25 years that speaker manufacturers do not build a speaker and then determine the parameters afterwards. whatever driver you are planning on using will have Thiel/Small parameters for it and those can be used to assist you in a cabinet design.

A Properly tuned pported cabinet is a more efficent enclosure than any 4th or 6th order. the other draw back is that these enclosures are usually used in complex systems with multiple drivers for different Frequency range tasks to fill in the the enclosure cannot.

Agreed, I much prefer sealed enclosures as they tend to be smoother and more accurate.

+1
if you are looking for an enclosure with high output try a coupl eof good 12" subs proted and tuned to about 28 Hz.

 

Although I've never been a fan of bandpass enclosures, they do have their place. I designed a bandpass enclosure for a member of another forum roughly a month ago because he wanted to run the port through his ski pass in his late model Maxima.

Another vehicle that bandpass enclosures seems to work well in are the BMWs with the port firing through the ski pass into the cabin. Historically, BMWs have been the more challenging vehicles to get bass into the cabin due to all that sheet metal behind the rear seats.

Lastly, before the invention of the Termlab and weighting, bandpass enclosures used to be a great way to cheat in SPL competitions because the port was tuned to peak at the frequency that the measurement microphone was most sensitive to.