There are always some differences within the same speaker model. The good thing about it is that most of them do not lead to different tunes in the cabinet, as they cancel each other out. One value is lower, one higher, the end result gives the same tuning in a given inclosure. Anyway, averageing should be a good idea.
Also, with many pro drivers there is a run in effect, which leads to a lower Fs after a few hours of intense use, usually leading to a slighly better low end output and less distortion. How much is very individual.
You should compare your measurements with the manufacturers data.
If you combine 4 drivers to run on the same amp , 2 in parallel, then both groups in series, you may match them for best coil resistance.
Also, with many pro drivers there is a run in effect, which leads to a lower Fs after a few hours of intense use, usually leading to a slighly better low end output and less distortion. How much is very individual.
You should compare your measurements with the manufacturers data.
If you combine 4 drivers to run on the same amp , 2 in parallel, then both groups in series, you may match them for best coil resistance.
Whoops I just noticed...the title of this is wrong, can a Moderator please change "cap" to "cab" as in cabinet?
I don't have/can't find the manufacture's data...the drivers are from an Ampeg BA-210v2...Eminence 10" custom made for this application. I acquired two more to re-build the combo amp into separates with a 4-10 cab and a separate amp head. So far, I have only partially measured the two replacement drivers I bought from Ampeg though an online Musical Instrument dealer, and even though they are about 10 - 15% different from each other in some specs, I don't suspect anything is wrong with them. I have been building Hifi speakers for decades, so I know what I'm doing, but I've never tried to calculate a cab with four drivers, so I need to know...do I just use a simple average of all the drivers measurements, or is some kind of "root of the sum of the squares" kind of thing necessary?
And just for the sake of clarity, they are sixteen ohms and will be wired in parallel for four ohms.
Mike
I don't have/can't find the manufacture's data...the drivers are from an Ampeg BA-210v2...Eminence 10" custom made for this application. I acquired two more to re-build the combo amp into separates with a 4-10 cab and a separate amp head. So far, I have only partially measured the two replacement drivers I bought from Ampeg though an online Musical Instrument dealer, and even though they are about 10 - 15% different from each other in some specs, I don't suspect anything is wrong with them. I have been building Hifi speakers for decades, so I know what I'm doing, but I've never tried to calculate a cab with four drivers, so I need to know...do I just use a simple average of all the drivers measurements, or is some kind of "root of the sum of the squares" kind of thing necessary?
And just for the sake of clarity, they are sixteen ohms and will be wired in parallel for four ohms.
Mike
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Take the data and average them as you like, do nothing complicated. Then simulate for one and multiply the volume by 4. There is no problem or secret tweak.
See, if you put all 4 on a baffle, with each driver it's own volume, then connect these volumes, nothing changes for the working condition of the individual driver. 10% difference between drivers are quite usual. You can't do better than do a simple average.
Most simulation software can handle more than one driver anyway.
See, if you put all 4 on a baffle, with each driver it's own volume, then connect these volumes, nothing changes for the working condition of the individual driver. 10% difference between drivers are quite usual. You can't do better than do a simple average.
Most simulation software can handle more than one driver anyway.
I understand how to do the calculations for single or multiple drivers...that's not the question. I just wasn't sure the proper way to combine the data from multiple drivers in a common volume to get the workable numbers. So, I will take all of the measurements and just do a simple average and go from there. Thanks.
Mike
Mike