Measuring room for room mode calculator - handling bookshelf irregularities

SwedishChef

SwedishChef

Junior Audioholic
I have a room that has 80% plus of 3 out of the 4 walls covered with floor to ceiling bookshelves. The books and other items provide a pretty irregular "surface." Should I measure from the wall or from the front surface of the books in order to put measurements into a room mode calculator? Or, with it being about 10% of the distance in each dimension, is it too small to worry about?
 
S

shadyJ

Speaker of the House
Staff member
If the bookshelves are packed with stuff, I would count them as a surface. If they are sparsely filled, I would just use the walls as the calculated surface.
 
SwedishChef

SwedishChef

Junior Audioholic
Thanks. They are pretty packed - books, boxes, etc. Perhaps the uneven surfaces scatter some high frequencies.
 
highfigh

highfigh

Seriously, I have no life.
I have a room that has 80% plus of 3 out of the 4 walls covered with floor to ceiling bookshelves. The books and other items provide a pretty irregular "surface." Should I measure from the wall or from the front surface of the books in order to put measurements into a room mode calculator? Or, with it being about 10% of the distance in each dimension, is it too small to worry about?
Since room modes WRT audio quality pertain to low frequencies, I would recommend using the room's dimensions or, at least, the face of the cabinets if they're actually attached to the walls and not free-standing. The books will still allow low frequencies to reach the walls, so that's the critical dimension although not all of the energy is reflected- some passes through. The irregular surface of the book bindings does help to diffuse the sound, but mainly in the midrange.
 
ski2xblack

ski2xblack

Audioholic Field Marshall
Bookshelves filled with books and other knickknacks will probably be beneficial as the higher frequencies will get some diffusion and absorption. Easiest way to address room modes, which @highfigh correctly points out as a bass phenomenon, is to use multiple subs.
 
ryanosaur

ryanosaur

Audioholic Overlord
If its not a total PITA, run both dimensions. If you have the extra data for the Bookshelf to Bookshelf dimensions vs the Wall to Wall dimensions, I'd think you'll have an easier time determining which modes which might be causing problems in your room. ;)
 
SwedishChef

SwedishChef

Junior Audioholic
I'm still playing with REW and Audyssey and trying to get things just so. I probably have several days of playing with things left. Fortunately I'm still finding it kind of fun, and not work. :) I definitely seem to have a wide bass issue centered on 37db in the main listening position that I still need to work on. I do have two subs to work with.

Here's a current REW graph with 1/6 smoothing. I'd like to see a bit more from 20-100 in addition to fixing the hole - may use a minidsp. With my room configuration I don't have a ton of options for changing screen or seating positions, so I hope moving the subs, playing with phase, etc. helps.
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