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Lighter weight sub?

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Tim McCulloch:
You don't need a lighter sub - 20 lbs won't make a significant difference with 17 steps- you need a helper AND bill the client for that person.

Chris Grimshaw:

--- Quote from: Paul G. OBrien on June 15, 2021, 11:52:51 PM ---Being a bandpass I anticipate it having a giant peak like response and for that reason I have always dismissed it thinking it will be a one note wonder.

--- End quote ---

Bandpass designs can sound as good (or bad!) as any other. I built one a little while ago (the chosen drivers practically forced a 4th order bandpass), and it sounded great once properly integrated.

A "gotchya" is that the bandpass forms its own acoustic crossover slope at the top end, so you've got to factor that in when programming your processor. A 12dB/octave Butterworth (electrical) slope might get you a resulting 24dB/octave Linkwitz-Riley.

There are plenty of badly-designed bandpass subs, and plenty of well-designed ones being used badly.


I quite liked the 4th order bandpass for the following advantages:
- No particular need for an infrasonic filter - it would provide some output at 10Hz on account of the sealed back chamber.
- With a pair of drivers, you can set the internals up for force cancellation. Bonus points if you get the port(s) passing cool air directly over the magnets.
- Smaller than a well-aligned ported box
- Lots and lots of output, albeit not going as low as a bigger ported box.

A double-edged-sword is that the acoustic bandpass filters out most of the distortion from the drivers. The sound stays pretty clean until the drivers are seriously struggling (and likely about to fail).

Chris

Steve-White:

--- Quote from: Tim McCulloch on June 16, 2021, 11:38:36 AM ---You don't need a lighter sub - 20 lbs won't make a significant difference with 17 steps- you need a helper AND bill the client for that person.

--- End quote ---
This +1.  They pay for stairs.  (period)

Brian Jojade:

--- Quote from: Steve-White on June 16, 2021, 02:10:12 PM ---This +1.  They pay for stairs.  (period)

--- End quote ---

And when the client complains, tell them to take it up with the venue that didn't have roll in access to their space available. Any other business has additional charges for this sort of thing. We need to be able to do exactly the same thing.

Steve-White:

--- Quote from: Brian Jojade on June 16, 2021, 03:08:28 PM ---And when the client complains, tell them to take it up with the venue that didn't have roll in access to their space available. Any other business has additional charges for this sort of thing. We need to be able to do exactly the same thing.

--- End quote ---

Exactly or move his event(s) to a venue with proper access.

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