speaker cabinets

[Fred Rushing]

What would be the difference in sound when comparing open back cabinets to closed back ported cabinets? All comments appreciated.
Fred. (steel guitar applications)

[David Doggett]

A closed back cabinet reflects all the sound out the front, eliminates any wrap around cancellation, and uses cabinet resonance to boost the bass. Therefore, it will sound louder, with stronger lows. A closed back cabinet also protects the speaker from blow-out. The main drawback to a closed back cabinet is that, if you put your amp toward the middle or front of the stage (front to back), drummers, bass players, etc. behind your speaker wont hear you well. Open back speakers can sound different depending on what is behind them. If they are backed up against a hard wall, that can reflect the sound forward and be louder, compared to no wall, or a heavy curtain.

[T. C. Furlong]

I agree with David's assesment except for one thing. With a closed back cabinet, mids and lows (frequencies below say 500Hz)will radiate around to the rear as much or more that with an open back cabinet. It's just the upper mids and high frequencies that will be attenuated behind the cabinet. As David points out, a properly ported, closed back cabinet will also sound more consistent from one location to another. This is because the rear cancellation of upper midrange frequencies is not as position dependent (distance from back wall, curtains,etc.) as with an open back design. I am currently doing a lot of listening and measuring both types of cabinets. It's very interesting stuff.

TC<font size="1" color="#8e236b"><p align="center">[This message was edited by T. C. Furlong on 25 October 2005 at 05:04 PM.]</p></FONT>

[Fred Rushing]

Thanks for the input fellas. I am using a pair of Marrs closed and ported cabinets and am really making friends with them. I do agree for sure the over all sound is more consistant from place to place and I really like that. Fred