[nathanm]

So if you mount a driver on a flat sheet of wood the bass response will increase the bigger the sheet is, right?  Assuming we are listening indoors the largest the baffle can get is roughly half the width of the room.  What is the difference then between mounting the driver on a piece of wood sitting inside a room and mounting the drivers into the wall itself?  (And the other side of the wall was also an empty room)  Is the idea of an open baffle that you are supposed to hear the rear of the speaker's output reflecting back at you between the space not taken up by the baffle?

I figure the biggest baffle that's domestically feasible would be a 4x8' sheet of plywood, right?  But is a 'large' baffle only desirable within a given room size?  I'm just trying to get a grasp on this stuff because I figure out of any DIY speaker project I could do, an open baffle has the highest likelihood of actually being finished.  I figure I can cut two lousy holes without getting lazy and abandoning the project!

[Brad]

What's this board with half a circle cut out of it?
Nathan?

Yes, the idea of OB is that you hear the back wave from the driver.

[nathanm]

Hey give me a break, the saw blade broke and the hardware store was closed!

[markC]

  What is the difference then between mounting the driver on a piece of wood sitting inside a room and mounting the drivers into the wall itself?  (And the other side of the wall was also an empty room)


The latter would be an Infinite Baffle set-up and it works great for subwoofer applications with the apropriate drivers.

[JLM]

In-wall speakers fall into two design camps: sealed and infinite baffle.  Speakers intended to simply fit between stud (small) spaces for instance would be designed as sealed cabinets.  Speakers that are provided with a large space behind them (4 - 10 times the driver's specified Vas) behave according to infinite baffle theory.  In either case there should be no baffle step compensation needed, OTOH soundstage depth is severely compromised.  Because of this diminished sound staging the best application for I.B. is for deep bass.

Just like O.B. bass use of multiple drivers and EQ is to be expected.  I.B. bass has no front/rear wave cancellation, but finding a suitable domestic installation can be a challenge.  Adjoining space is required.  Garages or attics may get too hot or cold.  Common ceiling/wall/floor construction to attics, spare bedrooms, or basements may be insufficient to prevent bleed through.  Swinging of doors into those spaces (if small and/or tightly sealed) can damage the drivers.

But the performance can be truly great.  There's even a forum for I.B. bass that has some extremely devoted members that seem to know their stuff:

http://home.comcast.net/~infinitelybaffled/

[oldtimer]

Part of the way we hear live music and percieve it as live music is the amount of direct/reflected sound reaching our ears. OB speakers reproduce that in some part, much more than box speakers anyway, and this is what can so apealing to some. The rear wave is thus an important part of the soundscape. Puting a driver in a wall would be not unlike just putting a driver in a box.

Happy listening
Nigel

[nathanm]

So you're getting more room reverb with an open baffle?

[opnly bafld]

more in front of and behind, less to the sides