Speaker position on baffle board

[andrewrx7]

Just looking at the various cabs/combos I have, both bass and guitar, and notice that all the bass speakers are mounted to the front of the baffle board, while the guitar speakers are all positioned behind the baffle. Is this purely co-incidental or is there a reason for this? Can't imagine a reason, but had me intrigued! Any thoughts?

[Mr. Foxen]

Guitar speaker cabs are made in a traditionalist way. Bass cabs tend to be made more practically. Plus internal box volume is a bit bigger deal for bass cabs.

[Bill Fitzmaurice]

It's easier to build a front loaded cab, as the back doesn't have to be removeable. Otherwise there's no particular advantage to either arrangement.

[Balcro]

For entertainment / musical instrument loudspeakers it doesn't matter, but purist hi-fi people tend to design loudspeakers with the frame flush to the baffle or with a surrounding trim piece to blend the frame into the baffle. Their argument is, that it minimises unwanted sound diffractions from the sharp edges of the cut baffle board. The ultimate aim or obsession being a flat frequency response.

Putting loudspeakers inside the baffle means the drive unit fires out into a 15-18mm deep tunnel, but as its for guitarists, who cares.

Maybe Bill will have a technical opinion on the validity of this "hi-fi" claim.


Balcro.

[Tankdave]

You can get at the back of the speaker with a guitar cab, but bass cabs usually got sealed up backs making it easier to fix the speaker from the front, that's my thinking

Edited July 14, 2012 by Tankdave

[Bill Fitzmaurice]

[quote name='Balcro' timestamp='1342261354' post='1732424']
For entertainment / musical instrument loudspeakers it doesn't matter, but purist hi-fi people tend to design loudspeakers with the frame flush to the baffle or with a surrounding trim piece to blend the frame into the baffle. Their argument is, that it minimises unwanted sound diffractions from the sharp edges of the cut baffle board. The ultimate aim or obsession being a flat frequency response.

Putting loudspeakers inside the baffle means the drive unit fires out into a 15-18mm deep tunnel, but as its for guitarists, who cares.

Maybe Bill will have a technical opinion on the validity of this "hi-fi" claim.


Balcro.
[/quote]For our purposes it's not true. For diffraction to be significant the obstacle must be at least 1/4 wavelength in dimension; at even 4kHz that's nearly an inch, so the driver positioning on the baffle doesn't matter with electric bass or guitar. In a hi-fi cab what can happen is that a woofer frame extending beyond the baffle can cause diffraction of the wave from a tweeter adjacent to it, so inlaying the woofer flush to the baffle may be beneficial, depending how thick the frame is.