So I am pretty green when it comes to DIY speakers so please bare with me 🙂. I am wanting to build a DIY portable bluetooth speaker. It will have two 6.5" woofers and two tweeters. I am planning on using a Wondom 2x50W 4ohm amplifier from Parts Express that has really caught my eye for what I am looking to do. I ordered the woofer already which is 4ohms (link) . I was looking at pairing it with this tweeter (link) which is also 4ohms.
I am really confused as to what I should do for a crossover. I was actually looking at getting something like this from Ebay (link) . It is listed as a 4ohm XO so I assume the amp will still see a 4ohm load so I will get it's full rated output and not worry about frying it due to a lower impedance. I was also thinking about it due to the fact that the tweeter I am looking at has a higher sensitivity than the woofer and that XO has selections for 0db,-3db,-6db to attenuate the tweeter some. I am just looking to see if I am even heading the right direction here.
-Mark
I am really confused as to what I should do for a crossover. I was actually looking at getting something like this from Ebay (link) . It is listed as a 4ohm XO so I assume the amp will still see a 4ohm load so I will get it's full rated output and not worry about frying it due to a lower impedance. I was also thinking about it due to the fact that the tweeter I am looking at has a higher sensitivity than the woofer and that XO has selections for 0db,-3db,-6db to attenuate the tweeter some. I am just looking to see if I am even heading the right direction here.
-Mark
The right direction? Probably yes. The things you are concerned about are reasonable but are more broad in nature than they may seem. This crossover could be seen as a starting point.
that crossover will not function well with the drivers in question.
the tweeter you selected should be crossed somewhere around 2.8 khz to ensure its working properly. not sure about those 6.5" er midbasses can go high enough to coop with them.
you would need a notch filter to smooth out the impedance bump at FS of the tweeter,
and you would need a zobel on the woofer to get rid of the rising impedance of the coil.
then you would have to make a 2nd order filter with the combined impedance in mind.
then an L-pad to get the tweeter down by about a good 4 dBL.
if i would be you i hazard i would be looking for a different set of drivers.
when you look for a tweeter, i would recommend making sure to choose something with less Fs. something around less 1 Khz would do the trick.
that would allow a crossover freqvency at bit over 2 khz, and its something worth a few extra bucks.
when it comes to midbass, the selection you made is not that bad, the size is right. 6.5" is about he maximum i would recommend, however its best to choose a driver that has a full datasheet available with freqvency response charts.
we would like the 30 degree off-axis curve to stay relatively flat till 2.5 khz ish , then it will work nicely with a tweeter that has less than 1Khz Fs.
now, you allready ordered the 5.5" er midbass units so we should work with those.
the tweeter you selected is not quite a suitable one for those midbass drivers.
however, they can work decently with this:
Dayton Audio DC28FT-8 1-1/8" Silk Dome Truncated Tweeter
probably it will be okay to use 1.8 khz crossover freqvency and 2nd order .
you still need a notch filter fro thisone.
good news is this tweeter is 8 ohms, so it may not need any padding to be suitable for your midbass units. (i know those are 4 ohm ones)
the tweeter you selected should be crossed somewhere around 2.8 khz to ensure its working properly. not sure about those 6.5" er midbasses can go high enough to coop with them.
you would need a notch filter to smooth out the impedance bump at FS of the tweeter,
and you would need a zobel on the woofer to get rid of the rising impedance of the coil.
then you would have to make a 2nd order filter with the combined impedance in mind.
then an L-pad to get the tweeter down by about a good 4 dBL.
if i would be you i hazard i would be looking for a different set of drivers.
when you look for a tweeter, i would recommend making sure to choose something with less Fs. something around less 1 Khz would do the trick.
that would allow a crossover freqvency at bit over 2 khz, and its something worth a few extra bucks.
when it comes to midbass, the selection you made is not that bad, the size is right. 6.5" is about he maximum i would recommend, however its best to choose a driver that has a full datasheet available with freqvency response charts.
we would like the 30 degree off-axis curve to stay relatively flat till 2.5 khz ish , then it will work nicely with a tweeter that has less than 1Khz Fs.
now, you allready ordered the 5.5" er midbass units so we should work with those.
the tweeter you selected is not quite a suitable one for those midbass drivers.
however, they can work decently with this:
Dayton Audio DC28FT-8 1-1/8" Silk Dome Truncated Tweeter
probably it will be okay to use 1.8 khz crossover freqvency and 2nd order .
you still need a notch filter fro thisone.
good news is this tweeter is 8 ohms, so it may not need any padding to be suitable for your midbass units. (i know those are 4 ohm ones)
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