Hi All.
How important is DCR matching, the type done with an average DMM, in pairs of mid/high compression drivers?
Pairs of compression drivers are sold online all the time that are measured this way and presented as matched for sale. Is this sort of measurement any indication of actual matching with respect to frequency response and SPL matching?
If it is, how close do two compression drivers have to be in this DCR measurement in order to be considered matched?
Also, if the drivers are mismatched, how do you go about matching them?
Thanks in advance for your replies!
How important is DCR matching, the type done with an average DMM, in pairs of mid/high compression drivers?
Pairs of compression drivers are sold online all the time that are measured this way and presented as matched for sale. Is this sort of measurement any indication of actual matching with respect to frequency response and SPL matching?
If it is, how close do two compression drivers have to be in this DCR measurement in order to be considered matched?
Also, if the drivers are mismatched, how do you go about matching them?
Thanks in advance for your replies!
DCR doesn't help except to tell you if you have an open or dead short. DCR is not useful at all in matching drivers otherwise. I think it's probably also true you could use DCR as a very rough guage of having a good or bad driver. Like, if it's 0 ohms, send it back, if it's infinite send it back. If it's 4 Ohms +- 0.5 Ohm it's probably worth more rigorous testing.
When drivers are matched, you want the acoustic output and impedance chart. Not a lot of hobbyists do this, especially since they usually can't afford enough drivers to find pairs that match better than others. If you buy 200 drivers however, you measure each one and use a computer to find the one's that are closest. Of course, some manufacturers have tighter tolerances than others, so you may discover after measuring a few that matched pairs is too much effort.
As a hobbyist, you buy 2 drivers, and hope for the best, but!!
What you can do is measure each driver and attempt to design a custom crossover for it.
You can use something like XSim to show you how each driver would work, and compare to see if there is enough of a difference to tweak the crossover in each speaker. It sounds like this could be fun. I have read of some manufacturers claim they do this for every single speaker.
Best,
E
When drivers are matched, you want the acoustic output and impedance chart. Not a lot of hobbyists do this, especially since they usually can't afford enough drivers to find pairs that match better than others. If you buy 200 drivers however, you measure each one and use a computer to find the one's that are closest. Of course, some manufacturers have tighter tolerances than others, so you may discover after measuring a few that matched pairs is too much effort.
As a hobbyist, you buy 2 drivers, and hope for the best, but!!
What you can do is measure each driver and attempt to design a custom crossover for it. You can use something like XSim to show you how each driver would work, and compare to see if there is enough of a difference to tweak the crossover in each speaker. It sounds like this could be fun. I have read of some manufacturers claim they do this for every single speaker.
Best,
E
Thanks for the quick reply. I am supposed to be picking up a pair of JBL 2425J drivers tomorrow that measure 6.8 and 7.5 Ohms. These are 16 Ohm drivers, so both numbers seem a bit low, and there is a .7 Ohm difference between them. I’m not very familiar with CDs, and was unsure if this difference would be a problem.
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