Set all to small. Crossover at 100, twice the low end of the mains. If you set the x/o lower, you will have a dip in the response because the speakers roll-off overlaps with the x/o roll-off. The 'double' roll-off won't sum together correctly with the sub's x/o causing a dip in the response between the mains and sub. (Setting to large will stress the speakers. They're not designed for handling very low frequencies.)
Showing 3 responses by ojgalli
Sounds below 80 Hz can be localized. The issue to address is not localization, but rather, a smooth, linear transition between mains and sub. It might be possible at 80 Hz, but highly doubt it could be done any lower with the Thiel 1.6. Velodyne's recommendation may be based on the fact that subs generally have a rising response in the mid-bass, by having a little 'gap' in the crossover it could help smooth out the hump, or the logic could be to help tame common room modes that often occur in the same frequency range. No matter how one looks at it, calibrating a sub is difficult. It requires time and patience. |
Found a few references. In a nutshell, Interaural Level Difference (ILD) and Interaural Time Difference (ITD) are the means for interpreting the location of a sound source. Level difference is mostly used for high frequencies due to wavelength relative to head size, yet the time difference is identical for low frequencies as for high. Time difference allows for low frequency localization. (See the abstract at this link, http://adsabs.harvard.edu/abs/2005ASAJ..117.2391B) The precedence effect also comes into play in a typical domestic room where one is listening relatively close to the source, and level differences are aided by proximity reinforcement. Try listening to sine waves coming from only the left or right channel. You can easily identify which speaker is producing the sound unless the frequency hits a room mode, then ringing may obscure the location cues. More reverberant spaces also make it more difficult to localize, even for high frequencies. Location cues tend to be easily obscured, and room acoustics can affect perception, for better or worse, making it difficult to determine a specific cut-off frequency. It's a convenience to say frequencies under X Hz are nondirectional. This link suggests learning is involved: http://www.ncbi.nlm.nih.gov/pubmed/7602671 This link goes into greater detail: http://www.aip.org/pt/nov99/locsound.html One more: http://www.ncbi.nlm.nih.gov/pubmed/1564201 |