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Posted this in the other Lineup Thread, but I thought I should post here to get some feedback on this. Maybe I'm overreacting?
JohnL brought up driver consistency of the W4 in the other Lineup Series thread and that sparked my interest in driver consistency tests. I just measured 6 D26s to see how similar the FRs are. I didn't touch the mic or speaker box location and kept the settings exactly the same. I tested in the Center Channel speaker box.
There was a 1-2db difference between some of the D26s. And some substantial differences in the low end output. That might mean that the Lineup Maxx might develop a slight peak around the crossover point depending on which D26 you get. I tried a few different tweeters in the Lineup Maxx, and found that a simple change of the Lpad can help matters.
I suggest the following changes to the Lineup Maxx crossover if you detect that the midrange and treble is a bit bright. Change the Lpad 15ohm resistor to something between 8-12 ohms. 8 will cut it the most. If you like that, you could try a 1.5ohm resistor in place of the 2.2ohm resistor in the Lpad. That will raise the top end a bit. Note that some of the D26s very as much as 1 db at the top end. Just post your observations and we can figure out the perfect values for your application. Note that a lot of DIY speaker designers offer a few different Lpad scenarios. Perhaps this helps deal with slight consistency variations.
What does this mean?
L-pad values on the D26 may need to be tuned by "ear" if you don't have measuring equipment. I'll give people different L-Pad options so they can tune it to their tastes, or if they happen to get one of the "hotter" tweeters. Unfortunately, I have no way of knowing which one of the D26s I used for the original measurements of the Lineup Series. I think it was one of the less efficient ones, but I didn't think I'd have to do this test at the time.
Jed
JohnL brought up driver consistency of the W4 in the other Lineup Series thread and that sparked my interest in driver consistency tests. I just measured 6 D26s to see how similar the FRs are. I didn't touch the mic or speaker box location and kept the settings exactly the same. I tested in the Center Channel speaker box.
There was a 1-2db difference between some of the D26s. And some substantial differences in the low end output. That might mean that the Lineup Maxx might develop a slight peak around the crossover point depending on which D26 you get. I tried a few different tweeters in the Lineup Maxx, and found that a simple change of the Lpad can help matters.
I suggest the following changes to the Lineup Maxx crossover if you detect that the midrange and treble is a bit bright. Change the Lpad 15ohm resistor to something between 8-12 ohms. 8 will cut it the most. If you like that, you could try a 1.5ohm resistor in place of the 2.2ohm resistor in the Lpad. That will raise the top end a bit. Note that some of the D26s very as much as 1 db at the top end. Just post your observations and we can figure out the perfect values for your application. Note that a lot of DIY speaker designers offer a few different Lpad scenarios. Perhaps this helps deal with slight consistency variations.
What does this mean?
L-pad values on the D26 may need to be tuned by "ear" if you don't have measuring equipment. I'll give people different L-Pad options so they can tune it to their tastes, or if they happen to get one of the "hotter" tweeters. Unfortunately, I have no way of knowing which one of the D26s I used for the original measurements of the Lineup Series. I think it was one of the less efficient ones, but I didn't think I'd have to do this test at the time.
Jed
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