Have (8) 5.25" woofers and would like to make a pair of smallish towers (TWWWW). How do I go about measuring the woofers to model a 2.5 way crossover via Xsim? Do I measure a single woofer in free air? Do I measure all the woofers together? I haven't started cutting wood yet, so I'm open to suggestions. I do currently have some 2-way monitors using the same 5.25" woofers. If the towers use the same baffle width, could I simply use the woofer measurements I attained from those, and import into Xsim? The woofers are SB15NBAC30-8
I've debated buying another 4 woofers and creating a ridiculously expensive version of Curt's Uluwatus.
I've debated buying another 4 woofers and creating a ridiculously expensive version of Curt's Uluwatus.
OK, a bit more information is required. How do you intend to wire up the four woofers? I assume the upper 2 woofers will be the "midrange" woofers and the lower two woofers will be the .5 woofers. Correct?
Also - do you know what 2.5 crossover topology you are going to use? AFAIK there are two types of parallel 2.5 way crossovers: The first has only an inductor in series with the .5 driver(s). The other, the more common cascaded 2.5, has the midrange low pass network in series with all drivers and then the .5 driver(s) has an additional inductor in series with the midrange driver(s).
And also - are all 4 woofers going to share the same cabinet space or will the upper two "midrange" woofers have their own cabinet space separate from the two .5 woofers? Measurements get complicated when all woofers share the same cabinet space because when you measure a single woofer (or pair of woofers in your case) the unused woofers act like passive radiators and affect the impedance & frequency response of the woofers under test. Having two chambers complicates cabinet construction (the two chambers should be equal in size) and requires two ports if you’re going ported.
Most 2.5 speakers I’ve seen use a common cabinet space. For an example of one that uses separate chambers (and an explanation of the benefits) see this Zaph audio speaker: Zaph|Audio.
As you can see, going 2.5 is a bit more complex than a standard 2-way.
PS - I see Charlie responded while I was editing my response.
Also - do you know what 2.5 crossover topology you are going to use? AFAIK there are two types of parallel 2.5 way crossovers: The first has only an inductor in series with the .5 driver(s). The other, the more common cascaded 2.5, has the midrange low pass network in series with all drivers and then the .5 driver(s) has an additional inductor in series with the midrange driver(s).
And also - are all 4 woofers going to share the same cabinet space or will the upper two "midrange" woofers have their own cabinet space separate from the two .5 woofers? Measurements get complicated when all woofers share the same cabinet space because when you measure a single woofer (or pair of woofers in your case) the unused woofers act like passive radiators and affect the impedance & frequency response of the woofers under test. Having two chambers complicates cabinet construction (the two chambers should be equal in size) and requires two ports if you’re going ported.
Most 2.5 speakers I’ve seen use a common cabinet space. For an example of one that uses separate chambers (and an explanation of the benefits) see this Zaph audio speaker: Zaph|Audio.
As you can see, going 2.5 is a bit more complex than a standard 2-way.
PS - I see Charlie responded while I was editing my response.
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Thanks for the input.
2 drivers as mid woofers, and the other 2 as .5 woofers. All drivers are 8 ohms
Its fairly easy to use separate enclosure partitions for each pair in a tower, so I will go that route. My initial assumption was to wire each pair in parallel, then wire the pairs in series, using an extra inductor on the bottom pair of woofers. I have the option to mount the bottom woofers near the floor for floor bounce, but haven't looked up how to quantify what I would gain in bass response.
If I measure each woofer pair, then import the FRD/ZMA files into XSim as single woofers, would my results be accurate enough to work with.
2 drivers as mid woofers, and the other 2 as .5 woofers. All drivers are 8 ohms
Its fairly easy to use separate enclosure partitions for each pair in a tower, so I will go that route. My initial assumption was to wire each pair in parallel, then wire the pairs in series, using an extra inductor on the bottom pair of woofers. I have the option to mount the bottom woofers near the floor for floor bounce, but haven't looked up how to quantify what I would gain in bass response.
If I measure each woofer pair, then import the FRD/ZMA files into XSim as single woofers, would my results be accurate enough to work with.
You would need a series 2.5 crossover if you wire each pair of drivers in parallel and connect them in series. The single inductor between woofers is for a parallel 2.5 crossover and won't work for woofers wired in series. I would wire each pair in series and then connect them in parallel with the inductor in between. YMMV.
Either way, if you measure one single driver you can have Xsim use it as four separate drivers, connect them in different ways and cross them separately.
There will be three minor discrepancies which you might want to know but which may not be of concern. One is that you might decide to run them in a separate box so the 0.5s get more extension, but when crossing you can use your imagination to ignore below 100Hz anyway. Second, the room can affect each woofer differently, but this is usually left out of speaker measurements, especially at this level. Thirdly, directivity of the multiple woofers however you are using the single measurement style so that could be marked off, and tweaked later by ear.
There will be three minor discrepancies which you might want to know but which may not be of concern. One is that you might decide to run them in a separate box so the 0.5s get more extension, but when crossing you can use your imagination to ignore below 100Hz anyway. Second, the room can affect each woofer differently, but this is usually left out of speaker measurements, especially at this level. Thirdly, directivity of the multiple woofers however you are using the single measurement style so that could be marked off, and tweaked later by ear.
Thanks. I'd prefer to start working on the crossover before I start cutting wood. I already have some 2-ways with an SB15NBAC30-8 in it. I was hoping to use the woofer files from that build. Once I build the enclosures, it wouldn't take much to conduct more measurements to double check. Ernperkins helped me decide to put each pair of woofers in their own equally sized partition.