Eric, you're right those did have foam plugs under the dome. I think we had dropped the foam plugs on some of the OEM units, the standard units still have them. My mistake!
On the difference between the F1 and F9, 1 dB would be in the manufacturing tolerance for these tweeters. There are a number of parameters that, when stacked up can lead to this variation. Dome mass (and suspension mass if Ti dome), glue mass, voice coil mass, voice coil position in the gap, etc. all have enough potential variation, even with good quality control, to lead to such a difference. My guess is the specs were not made from units that were tested to be nominal units but from random units from an early production (or even preproduction) run. If you examine the published curves closely you'll find that there is probably less than 1 dB difference between the two. Ahh... the joys of building tweeters!
On the difference between the F1 and F9, 1 dB would be in the manufacturing tolerance for these tweeters. There are a number of parameters that, when stacked up can lead to this variation. Dome mass (and suspension mass if Ti dome), glue mass, voice coil mass, voice coil position in the gap, etc. all have enough potential variation, even with good quality control, to lead to such a difference. My guess is the specs were not made from units that were tested to be nominal units but from random units from an early production (or even preproduction) run. If you examine the published curves closely you'll find that there is probably less than 1 dB difference between the two. Ahh... the joys of building tweeters!
True, I remember looking at the curves and thinking that they looked very much the same.
Why would one want to use a soft dome without a pad underneath? Higher sensitivity? Brighter sound?
Regards,
Eric
Why would one want to use a soft dome without a pad underneath? Higher sensitivity? Brighter sound?
Regards,
Eric
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