If you have the part info, maybe someone here can find more information on those drivers. Posting the TS parameters would at least be better than absolutely nothing.
On the crossover question, I think you could do with some basic review. Usually the lpad is *part* of the crossover. The lpad is in the crossover. (apoligies if that sounds agressive, just trying to answer your question)
There is very little to go on but I've seen the following type of crossover used in heaps of commercial centre speakers and all in one systems from Asian manufacturers such as Denon, Pioneer etc.
I've made assumptions on where the impedance plot would be at around a xo frequency of around 4000Hz. I chose this frequency as the tweeter Fs may be around 1500Hz so you do not want to cross over too low.
C1 = 4.7uF MKP (polypropylene) capacitor (alt 5.6uF)
L1 = 0.33mH air core inductor 18AWG (1mm) (alt 0.39mH)
You can see where the L-pad fits in showing series and parallel resistor and leave that up to you. Usually the series in much smaller in value to the parallel. 7dB is a lot to drop and I don't know how you got that number. You can buy variable L-pads that you turn to tune.
Best to start with the tweeter only with C1 + L-pad and run the woofers fullrange which may be all you need. Then you can add L1. Tweeter is usually +ve polarity in this type of crossover but you can try reversed (-ve polarity) to see if it sounds better.
Hope this helps.
I've made assumptions on where the impedance plot would be at around a xo frequency of around 4000Hz. I chose this frequency as the tweeter Fs may be around 1500Hz so you do not want to cross over too low.
C1 = 4.7uF MKP (polypropylene) capacitor (alt 5.6uF)
L1 = 0.33mH air core inductor 18AWG (1mm) (alt 0.39mH)
You can see where the L-pad fits in showing series and parallel resistor and leave that up to you. Usually the series in much smaller in value to the parallel. 7dB is a lot to drop and I don't know how you got that number. You can buy variable L-pads that you turn to tune.
Best to start with the tweeter only with C1 + L-pad and run the woofers fullrange which may be all you need. Then you can add L1. Tweeter is usually +ve polarity in this type of crossover but you can try reversed (-ve polarity) to see if it sounds better.
Hope this helps.
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Amazing reply Rabbitz, I really appreciate you taking the time to help.
My -7db for the tweeter is based on the spl at 1m which is quoted in the specs.
The reason for my question was I wasn't sure if the resistors in the lpad would effect the crossover as wouldn't the lpad change the overall impendence when combined with the tweeter?
My -7db for the tweeter is based on the spl at 1m which is quoted in the specs.
The reason for my question was I wasn't sure if the resistors in the lpad would effect the crossover as wouldn't the lpad change the overall impendence when combined with the tweeter?
The correct L-pad does not alter the filter but a single series resistor will. Have a look at the Z out number in that calculator in post 17.
The odds are you may not nail the correct tweeter attenuation first go as it may take a few attempts so do some calcs for a few different levels and have a hand full of 10W resistors.
The odds are you may not nail the correct tweeter attenuation first go as it may take a few attempts so do some calcs for a few different levels and have a hand full of 10W resistors.
I'm guessing you get the resistors that are closest to the figure you're trying to achieve?
You have helped me out massively, time to order some parts
Pick resistors as close as you can. Remember, it's a voltage divider so keep the ratio R1/R2 as close as possible. Such as it you pick a R1 actual value then try values for R2 either side but generally if you go larger in R1, R2 would need to be larger as well to maintain the ratio.
You can play around in that calculator using dB attenuation to 1 decimal point such as 5.8dB to get a R1 value that's available.
You can play around in that calculator using dB attenuation to 1 decimal point such as 5.8dB to get a R1 value that's available.
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