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Bill Fitzmaurice

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About Bill Fitzmaurice

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  1. Those are Eminence Deltalite 2510, first generation. They were superseded by the Deltalite II 2510 some 15 years ago. The first gens had heat problems, which was fixed on the second generation with a better magnet heatsink.
  2. True, and it goes deeper than that. As far as the actual tone controls are concerned a 12:00 setting may be neutral, as in zero boost, zero cut. That's the case with most SS front end amps. But with a valve front end 12:00 could be 6dB or more boost. As for flat, most amps are incapable of flat response, and you wouldn't it any more than you'd want flat beer.
  3. You can model the effect on the lows in WinISD 0.7 by changing the Qa value. The effect on the mids and highs is fully reached with only an inch or two. Damping does not occupy acoustic volume, so you don't compensate for it.
  4. Insufficient data. Cone area is only one part of a complex equation.
  5. Just because a driver is ceramic that doesn't mean it's heavy. For instance, 2.04kg: https://www.eminence.com/speakers/speaker-detail/?model=Alpha_10A Being neo doesn't men it's light. For instance, 2.09kg: https://www.eminence.com/speakers/speaker-detail/?model=DeltaliteII_2510 The difference in the price of these examples is significant, but so is the difference in performance, and it has little to do with the magnet material. One thing you can deduce, however, is that when a ceramic driver is light weight it's probably a weak performer as well.
  6. And now you know why the Grateful Dead Wall of Sound was so high.
  7. Not much. A line source drops 3dB per doubling of distance. To be a line source it must be at least three wavelengths high. That's easy at 5kHz, where a wavelength is around 7cm, not so much at 100Hz, where a wavelength is around 340cm.
  8. None, provided the rear ports aren't blocked. However, the usual reason for rear porting is that the cab is too small to fit them on the front. The smaller the cab the more likely that it will boom in the upper bass and be shy in the lower bass, so for that reason rear ported cabs may sound different than front ported.
  9. You have to be careful using raw driver curves. They are measured with the driver mounted in a wall, so they're only accurate above where an enclosure affects the result, roughly 150Hz. A sealed cab doesn't add much, if anything, in the lows, but a ported cab will make the lows very different.
  10. Response of a Fridge will be reasonably close to the chart for the Eminence B810. https://www.eminence.com/speakers/speaker-detail/?model=Legend_B810 The only significant difference is that in a sealed cab there will be a response hump centered around 110Hz.
  11. You could leave it in the case, but then it's probably thicker than you need. My wife also collected pillows, and bowls, and umbrellas, and more shoes than a centipede could make use of.
  12. See if you can nick an old pillow from Mum. Just be sure it's not filled with feathers.
  13. The best material is rigid Type 700 fiberglass boards, but it's not easy to come by. Next best are open cell foam and polyester batts. Fiberglass blankets, as used in home insulation, doesn't work as well, and it fractures easily. I never use it. Rockwool works well.
  14. Adding a second identical speaker in parallel gets 6dB additional voltage sensitivity, so with the same amp settings it's 6dB louder. It's not about the power going up by 3dB, that's just a side effect of the halving of impedance resulting in a doubling of current, which doubles power Maximum displacement limited output is also 6dB higher, because the system displacement is doubled. Now, if you wire another set of parallel wired identical speakers in series with the first, as is the usual case with a 410, voltage sensitivity remains the same, so it won't go louder than the 210 at the same amp setting. However, since the impedance has doubled the 410 can take twice the voltage as the 210, so if the amp has the available voltage to give the 410 can go 6dB louder than the 210, 12dB louder than the 110.
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