i am running 2 way of dual 4ohm dayton rs225 and dynavox tweeter in the midle each set. each set using dayton 2k 2 way crossover in 90lit ported cabine .it is sound bad! much worse then the set i tried to "upgrade" i don't realy know why (all conections,wires leads ,and flushs done triple checked)wy ques is:can i split my dual 4ohm rs225 using this xo so one will run 375hz as low pass (saperated inside the cabine) the other will run as a mid (8") and the 8ohm dynavox tweeter for the high passActually right now I do not know why but the speakers sound very bad (bass is very wick and the midrang sound like big mass) 3way transition is the only thing I think of to seperate freq'sthanks for the help
Doing as you suggest would actually make things quite a bit worse. The RS225 needs to be crossed over really low because since it has a metal cone, it has extremely sharp breakup frequencies. That is, for this particular woofer around 5kHz and 7kHz, there are sharp spikes in its frequency response, spikes that are over 10dB high. This type of breakup occurs with all metal-cone woofers, and the larger the woofer, the lower the frequencies that they occur at (in fact, breakup occurs with all types of speakers, but is much more prominent in metal-cone speakers).To deal with breakup frequencies, the woofer must be crossed over really low, with a steep roll-off (often 18 or 24dB/octave), and/or notch filters must be added to the crossover. For the RS225, it is generally recommended that if it is crossed over at 2kHz then a 4th-order (24dB/octave) crossover must be used. Alternately, crossing over at 1.5kHz with a 12dB/octave slope would work. Many people add notch filters on top of this. Crossing over any higher, or with shallower slopes, will make the spikes at the breakup frequencies very prominent. In your case, with a 2kHz, 12dB/octave slope, you will definitely notice the spikes at the breakup freqs, and this is probably why the midrange isn't sounding good. If you used one of the woofers as a midrange, then the breakup freq spikes will be EXTREMELY prominent.Also note that when crossing over at low frequencies, such as 2kHz and 1.5kHz, you have to make sure the tweeter can handle it. For a tweeter to be able to handle these low crossover points, it must be physically large (at least 1” diameter), have a low self-resonance frequency (approx 800Hz or lower), and must have a fairly high power handling (at least 30W). If these conditions aren’t met then the midrange/treble can sound “strained”, and unwanted resonances may occur.You mentioned that bass is weak, which is surprising for these woofers. A 90-litre cabinet is a good size for 2 of these woofers, so it's probably not the internal volume that is the problem. If you designed this cabinet with speaker-box software then check it over once again, and make sure the port size/length is exactly what it should be. If you used a pre-made design that you found online, then that design probably isn’t very good, and you’ll want to find a new design. If this is a pre-existing box that was originally made for different types of woofers then that would explain a lot. Ported boxes are very specific to the particular woofers in them, so putting a different woofer in a pre-existing ported box most often won’t work, and would result in poor, muddy bass, and bad midrange. To fix this, the solution could be as simple as making the port a bit longer, but to know for sure you’d need to simulate the box in some speaker-box software. If you need speaker-box design software then I would suggest WinISD. It is an easy program to get started with, and is actually quite powerful. Using a program like that, you can simulate your current box to see what its theoretical frequency response would be, and then adjust the parameters (such as port size/length, internal volume, etc) until the response is good.I think the best solution for your situation would be to first make sure the current box is properly designed for these woofers (using software), and then buy a dedicated midrange driver, and make a 3-way system with a crossover such as the one this question is listed under. Or, if you’re comfortable with designing your own crossover then do so because that would produce much better results.If you can’t add a midrange to the speaker cabinet (which looks like might be the case, from the looks of your picture), then your options will be more limited. One option would be to buy different woofers that can be crossed over higher. Paper- and poly-cone woofers can generally be crossed over at high frequencies, but there are exceptions, especially when it comes to 8” woofers. Also, as I said above, putting in a different set of woofers to a pre-existing cabinet often will have bad results. Or, you could stick with the RS225’s, but use a custom-made 4th-order, 24dB/octave crossover, along with notch filters. But, that is a very difficult crossover to design, especially if you’re only a beginner.
Date published: 2013-02-02