ligs Posted November 9, 2014 Report Share Posted November 9, 2014 I find the following graph very intriguing as it appears with the quote below from http://www.ebay.com/itm/PAIR-ACOUSTIC-RESEARCH-AR3-AR3a-MIDRANGES-/291289667620?pt=Vintage_Electronics_R2&hash=item43d2379824"These are fully functioning midranges, but not perfectly matched as depicted in the frequency response plot in pic three using a sweep signal through a 25 uF capacitor. The level of the outputs are identical as the signal strength and mike placement were the same. The red response is for the older driver and the green response is for the 200010-1. For those not familiar with this nearfield response, the flat response is typical. It's only when the mike is located some distance from the driver that wall effects produce the typical jagged response.The driver with the wire leads is probably from an AR3 or LST and dates to 1970-3. The other driver with the connecting posts underneath is labeled 20010-1 and probably dates to 1974-6." I don't know much about close mic measurements but they are generally used only for woofers also both midranges look like 1.5" to me. Link to comment Share on other sites More sharing options...
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