Phil A
Senior HTF Member
Some good suggestions above but before you get a sub measure how low they actually go in your room where they will be placed. Bass frequencies sum, so you want to cross over the sub at a point just below where the mains drop off, otherwise you will get that bass bump. For example if they really drop off at 100HZ, you want to cross it over below 100HZ and I would also recommend that the sub be located not that far away from the mains as well if it is crossed over that high.
You may find that your room reinforces certain frequencies based on its dimensions, speaker placement and decor. So I would not automatically assume 100HZ. If you can't get your hands on a RTA to measure then an SPL meter along with a test disc (e.g. http://www.delosmus.com/cgi/cart/ite...35011077199456) that has a good set of bass test tones (that disc counts down from the low 160HZ area so it covers a wide spectrum vs. something like: http://mdf1.tripod.com/test-tones.html which can be downloaded). I would also only get something that you can audition with your speakers on a trial basis.
You may find that your room reinforces certain frequencies based on its dimensions, speaker placement and decor. So I would not automatically assume 100HZ. If you can't get your hands on a RTA to measure then an SPL meter along with a test disc (e.g. http://www.delosmus.com/cgi/cart/ite...35011077199456) that has a good set of bass test tones (that disc counts down from the low 160HZ area so it covers a wide spectrum vs. something like: http://mdf1.tripod.com/test-tones.html which can be downloaded). I would also only get something that you can audition with your speakers on a trial basis.