Hi
Im doing a my first "real" 2-way speaker design, i have have dabbled before with few designs but this time will do it correctly taking time, measuring, building foamcore prototypes and modeling with vituixcad.
Thing is that i am wondering, is could active crossover help with design? (My midwoofer is Audio Technology 18H52)
I would need to try few crossover points to find out which could work out best for my taste, like 1600hz, 2200hz, 3000hz, 3400hz etc..
(with particular tweeter im testing)
Active could help out making this easy to try what i like, so i will know what crossover point i will take when i start modeling, right?
Im doing a my first "real" 2-way speaker design, i have have dabbled before with few designs but this time will do it correctly taking time, measuring, building foamcore prototypes and modeling with vituixcad.
Thing is that i am wondering, is could active crossover help with design? (My midwoofer is Audio Technology 18H52)
I would need to try few crossover points to find out which could work out best for my taste, like 1600hz, 2200hz, 3000hz, 3400hz etc..
(with particular tweeter im testing)
Active could help out making this easy to try what i like, so i will know what crossover point i will take when i start modeling, right?
It could. If you're hoping to save time, you'd want to be planning to model your digital filters to suit your system rather than just dialling them up and seeing how they sound.
This is my way to design multiway speakers. First I measure the drivers (impedance to know how not to kill them and fr to know what they cover), make a best guess what could work as crossover points, enter that into a DSP and use a multi channel chip amp (ICs are all the same) and listen and measure. When I have decided on crossover frequencies and filter types I design the passive crossover in VituixCAD. Unless I screwed up the fr plots of active and passive are the same.
You're correct, they are the same in theory. If I've not misunderstood you, you're not going to get the theoretical response with the active filters unless they also work against the driver/system variations.
How do you match up phase, passive vs DSP? Or passive vs active non-digital? Thanks.
my way is also as from shiirrn described. Sure there are limitations. Therefore, i design in VituixCAD parallel to the measurements and listening over the DSP. I had a nice sounding options over the DSP, that a have to cancel right away, because it was impossible to achieve them in passive Xover. Or i model different options in VituixCAD first and then i check all of them over the DSP to decide.
I haven’t built a box speaker in years, so this mostly applies to horns: I physically time align drivers. This also phase aligns them.
I can recreate the phase change of a passive filter I am emulating in the digital realm.
This is important anyways when going digital for develpment to keep in mind what can be done passive. So it doesn't make sense to elaborately eq all drivers flat when you want to go passive in the end. It is to make (subjective) choices regarding filter orders, attenuation and crossover points in a way that is way cheaper and faster then changing parts all the time and which also gives you a chance to easily do A-B or A-B-C-.... comparisons.
I can recreate the phase change of a passive filter I am emulating in the digital realm.
This is important anyways when going digital for develpment to keep in mind what can be done passive. So it doesn't make sense to elaborately eq all drivers flat when you want to go passive in the end. It is to make (subjective) choices regarding filter orders, attenuation and crossover points in a way that is way cheaper and faster then changing parts all the time and which also gives you a chance to easily do A-B or A-B-C-.... comparisons.
Thanks, a follow-up question re: physically time-aligning them. Only works at one frequency so the XO better be steep?
Aside: I was experimenting with this (2-way not horn) two nights ago and to my surprise there was a very precise offset for the most coherent sound regardless of musical instrument frequency range (cello/soprano/violin/etc.). Yes the offset corresponded (nearly) to the 1st-order HPF frequency so in-phase there but of course nowhere else. The midwoofer was run straight-through.
Aside: I was experimenting with this (2-way not horn) two nights ago and to my surprise there was a very precise offset for the most coherent sound regardless of musical instrument frequency range (cello/soprano/violin/etc.). Yes the offset corresponded (nearly) to the 1st-order HPF frequency so in-phase there but of course nowhere else. The midwoofer was run straight-through.
You are right. But this one frequency is where it matters most as you want sounds with that frequency to not arrive twice. And then there is also a region around that frequency that is still aligned well enough and beyond that it hopefully doesn't matter anymore. Steep filters make the shared part of the frequency range smaller and you need less hope that it "doesn't matter anymore".
FWIW: my current main speakers use first order filters for the upper three ways and even whith such huge overlaps it makes a difference. Measurable and with regards to the spongy subjective stuff like imaging, clarity, dynamics.
FWIW: my current main speakers use first order filters for the upper three ways and even whith such huge overlaps it makes a difference. Measurable and with regards to the spongy subjective stuff like imaging, clarity, dynamics.
A thing to try is take the phase plot into consideration when choosing crossover points and cross so there is no hard step in the phase response.
But what you winn on the phase when adjusting it passive you lost it on the curve shape... it could be not as smooth spl curve, no ? Big advantage to dsp here where you can setup the phase in FIR without touching the amplitude of the curve in the passband if I understood it well.
What is the tweeter to be used?
edit: There is a spirit wind loudspeaker kit by our late member Jeff Bagby, comprised of 18H52 and revelator tweeter. Perhaps there is a schematic available for free to download. In order to make this woofer play optimally, you need not a lot of parts to try out. A 2nd order electrical should suffice. X/O around 2k or so.
edit: There is a spirit wind loudspeaker kit by our late member Jeff Bagby, comprised of 18H52 and revelator tweeter. Perhaps there is a schematic available for free to download. In order to make this woofer play optimally, you need not a lot of parts to try out. A 2nd order electrical should suffice. X/O around 2k or so.
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Thanks, i actually have it already and im basing my speaker build on that foundation.
(cabinet will be exactly same, photoshop mockup added just for interest..).
I already have two tweeters though that are different from the kit, and anyway since im very sensitive to sibilance i want to try them first could they work (bliesma t25s-6 and SBacoustic tw29txn-b)
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Not necessarily. If you want to do something that is too complex often it means you are not doing it for the right reasons. Often there is an acoustic reason behind it to look at first.
Anything you can do digital you can also do passive. Some things are not well known, some are not simple, but they can.