hi guys,
I just need some clarification on this problem. I'm about to put together an open baffle 2 way speaker with an 8" mid driver and a Ribbon G2Si active system controlled by a Driverack.
Assuming I got the centers aligned between the mid driver and the ribbon (which effectively means phase aligned), and I'd use a 50uF cap to protect the tweeter, and crossing over at about 2Khz (which effectively should be far away from the cap's roll off response), will my effective phase delay between the 2 drivers still remain at 0 degrees ?
I just need some clarification on this problem. I'm about to put together an open baffle 2 way speaker with an 8" mid driver and a Ribbon G2Si active system controlled by a Driverack.
Assuming I got the centers aligned between the mid driver and the ribbon (which effectively means phase aligned), and I'd use a 50uF cap to protect the tweeter, and crossing over at about 2Khz (which effectively should be far away from the cap's roll off response), will my effective phase delay between the 2 drivers still remain at 0 degrees ?
If your drivers have no phase shift and if you can implement a crossover despite the impedance magnitude and phase variations (OK active) and if that crossover shows phase coherence, then yes.
In other words no.
If it were me, I would measure the drivers in place, and simulate a crossover with the measured results. If seems you care enough about phase aligment, I don't think you will be disappointed.
In other words no.
If it were me, I would measure the drivers in place, and simulate a crossover with the measured results. If seems you care enough about phase aligment, I don't think you will be disappointed.
Will said:
(JPK) Alinging the driver's centers (I presume you mean acoustic center) does not impliy zero phase difference between the drivers. It implies that at any point equal distance from both drivers' acoustic centers (i.e. on axis) the phase difference between the drivers will be equaly to the difference between their respective minimum phase responses. This will vary with frequency.
Re: Re: What's the effective delay ?
The driverack does have measurement capabilities to autoeq driver response but not to the extent of allowing the user to know phase relationship. Anyhow it's good to know that as long as the cap is large enough in the tweeter it will not bother too much with the phase relationship at the crossover region.
Yes aligning the acoustic centers. My target is to get the phase aligned at least at the crossover region (which is the whole point isn't it).
lndm said:
The driverack does have measurement capabilities to autoeq driver response but not to the extent of allowing the user to know phase relationship. Anyhow it's good to know that as long as the cap is large enough in the tweeter it will not bother too much with the phase relationship at the crossover region.
john k... said:
Yes aligning the acoustic centers. My target is to get the phase aligned at least at the crossover region (which is the whole point isn't it).
lndm said:
I'll be using a Fostex FE206, which should be more forgiving. Perhaps after all that building and theoretically determining the delay, I'll play a solo piano piece and see if the transients are sounding real and right. Then I'll change the tweeter delay by iteration to make it sound the best I can.
Greets!
Hmm, aligning the acoustic centers isn't sufficient since it doesn't account for the HF's 1st order XO's delay, so once the acoustic centers are found, then the HF needs to be either moved back or digitally delayed ~1.7" or ~0.125 ms. Problem is, without proper measuring equipment you don't have a clue where these centers are at, so the procedure is to align the VCs, wire the HF reverse polarity, set both drivers to equal amplitude, and with a 2 kHz (in your case) tone, move the HF backward and forward slowly until the deepest null is measured with a RTA/SLM/whatever (6-8 dB is good), or your ears if it's all you've got. Change the HF connection to positive polarity.
GM
Hmm, aligning the acoustic centers isn't sufficient since it doesn't account for the HF's 1st order XO's delay, so once the acoustic centers are found, then the HF needs to be either moved back or digitally delayed ~1.7" or ~0.125 ms. Problem is, without proper measuring equipment you don't have a clue where these centers are at, so the procedure is to align the VCs, wire the HF reverse polarity, set both drivers to equal amplitude, and with a 2 kHz (in your case) tone, move the HF backward and forward slowly until the deepest null is measured with a RTA/SLM/whatever (6-8 dB is good), or your ears if it's all you've got. Change the HF connection to positive polarity.
GM
GM said:
I don't quite understand this. Where's the factor that caused the 1st odrer roll off (which should not be from the cap since I'll be using 50uF) ?
GM said:
That's a good suggestion thanks. In my case I'll have to use my ears. The best part about using the digital xo is that I can change the delay on the fly.
Greets!
Apparently I 'saw' what I expected to see when scanning the thread. You're right, its impact would be insignificant. My bad.
Regardless, you'll still have to account for whatever XO slope you do use, so any higher order will increase the delay required, but as you note, it's just a twist of the knob away with a Driverack.
GM
Apparently I 'saw' what I expected to see when scanning the thread. You're right, its impact would be insignificant. My bad.
Regardless, you'll still have to account for whatever XO slope you do use, so any higher order will increase the delay required, but as you note, it's just a twist of the knob away with a Driverack. GM
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