Theoretically the 300Hz crossover sounds logical. My ~2001 B&W Nautilus 804's had x-over at 350 Hz. I think B&W uses 4th-order. It had a single 150mm midrange and dual 165mm L-F.
When I switched over to single full range speaker I could easily hear the B&W breaking up the L-F into pieces. Maybe because of my hard walled / highly reflective small room? Who knows? Ears are unreliable.
The typical subwoofer x-over of 50-80 Hz sounds like a bad idea as far are coherency.
When I switched over to single full range speaker I could easily hear the B&W breaking up the L-F into pieces. Maybe because of my hard walled / highly reflective small room? Who knows? Ears are unreliable.
The typical subwoofer x-over of 50-80 Hz sounds like a bad idea as far are coherency.
Each side of my current system has an RSS460 on the bottom end sitting right on the floor, actively crossed over at 150 Hz to a bookshelf system sitting about a metre high, comprised of a Purifi PTT6.5W08 passively crossed over to a Seas Aircirc at about 2100 Hz / 4th order.
I like 160 Hz because it doesn't mess up snare drums or voices too badly (linear phase is in the plans), and bounce for the woofer is not an issue when the driver is inches above the floor. Balancing between bass and mid is also a sight simpler than at 100 Hz. Bounce frequency for the mid should occur at 240ish Hz but that doesn't seem to be a problem, maybe because the rest of the room is filling in the blanks at that range. All three drivers are well-behaved an octave beyond their rolloff points; I'm not a huge fan of setting crossover points at arbitrary frequencies to satisfy ideological urges.
I like 160 Hz because it doesn't mess up snare drums or voices too badly (linear phase is in the plans), and bounce for the woofer is not an issue when the driver is inches above the floor. Balancing between bass and mid is also a sight simpler than at 100 Hz. Bounce frequency for the mid should occur at 240ish Hz but that doesn't seem to be a problem, maybe because the rest of the room is filling in the blanks at that range. All three drivers are well-behaved an octave beyond their rolloff points; I'm not a huge fan of setting crossover points at arbitrary frequencies to satisfy ideological urges.
I 100% recommend listening tests to help figure out the grey areas, like balancing orthogonal compromises 'against' each other.
Take for instance, a 200 Hz XO point, which gives good phase overlap between a certain bass and midrange. But the midrange is small and its distortion may start to climb as its cone starts to flutter, which is a completely unrelated thing, except that if you change one you must also change the other.
Without overthinking it, you may also find that (for personal DIY, that is) you tune the sound to your preferred listening level. Typically, as volume levels change, the optimal crossover points change because the speaker tone changes.
Take for instance, a 200 Hz XO point, which gives good phase overlap between a certain bass and midrange. But the midrange is small and its distortion may start to climb as its cone starts to flutter, which is a completely unrelated thing, except that if you change one you must also change the other.
Without overthinking it, you may also find that (for personal DIY, that is) you tune the sound to your preferred listening level. Typically, as volume levels change, the optimal crossover points change because the speaker tone changes.
Measurements of the Purifi midrange show distortion rising below 140-160 Hz no matter the drive level, with lower levels of course showing lower distortion, and above that point the thing is quite well-behaved. Other drivers around the same diameter (7 inches / 17 cm) have more or less the same characteristics.
High-excursion woofers typically run a few millihenries of voice coil inductance, which limits their response above a few hundred Hz. The Dayton RSS460, for example, is 3 dB down at 250 Hz. Given that LR4 crossovers are 6 dB down at the crossover point, the combination of midrange distortion rise and woofer rolloff tends to be minimised right around 160 Hz.
High-excursion woofers typically run a few millihenries of voice coil inductance, which limits their response above a few hundred Hz. The Dayton RSS460, for example, is 3 dB down at 250 Hz. Given that LR4 crossovers are 6 dB down at the crossover point, the combination of midrange distortion rise and woofer rolloff tends to be minimised right around 160 Hz.
For large 3 ways with a decent ca. 12" LF driver I prefer 330 hz with a max 2nd order slope, preferably 2nd order Besel or LR. Z With a typical 25mm dome in a 5 - 6" LF 2 way or, 3.5k is what sounds best to me, being you're not in the phase sensitive area of the ear and you can use a really good cone driver with nice midrange extension and little beaming. Id stay clear of a crossover in the 1k - 3k area, especially with steep sloped filters.