Room gain and baffle step

[Scarface1]

Hi, i was wondering how much bass boost you can get in a small room( 6 meter/20 feet ). I know that if you put a speaker to a wall you get some bass boost (because of baffle step?). I also know that room gain is +12db at wave lenght similar to longest wall( starts at half of that distance ).
i know other things count like air leaks, open doors, how many walls or curtains but am i seeing it right? Is the bass gained by placing the speaker to the wall the same bass as the roomgain or are those different from each other. I hope you get my point because english is not my native language! Thanks!

[billfitzmaurice]

You get bass boost close to a wall from space loading. It occurs below where the distance to the wall is less than 1/4 wavelength. Where it is 1/4 wavelength you get a boundary reflection null as much as 24dB deep, so to avoid that subs are usually placed close to the wall, mains further away so that the 1/4 wavelength distance is below their passband. Cabin gain takes place below where the longest room dimension is 1/2 wavelength. 12dB/octave is possible with a very tight room, but 9dB/octave is more typical. These are two different and distinct effects.

[4thtry]

I like to sim the amount of bass boost by plugging my woofer position, cabinet, and relative boundary locations into Jeff Bagby's "Baffle Diffraction and Boundary Simulator." The program can combine the effects of baffle step, room gain, and Allison effect room boundary reinforcement into a single graph.

http://audio.claub.net/software/jbabgy/BDBS.html

[Scarface1]

Thanks, i gonna download it.

[Scarface1]

You get bass boost close to a wall from space loading. It occurs below where the distance to the wall is less than 1/4 wavelength. Where it is 1/4 wavelength you get a boundary reflection null as much as 24dB deep, so to avoid that subs are usually placed close to the wall, mains further away so that the 1/4 wavelength distance is below their passband. Cabin gain takes place below where the longest room dimension is 1/2 wavelength. 12dB/octave is possible with a very tight room, but 9dB/octave is more typical. These are two different and distinct effects.

Ok Thanks! So the baffle step loss reflect on the wall behind the speaker and bouncing back it works the same as speakers coupling but now it is the reflection instead of the driver normally next to it?

[billfitzmaurice]

The rear wall reflection offsets the baffle step loss provided the distance from the baffle to the wall is less than 1/4 wavelength. That's why one shouldn't necessarily always use BSC.