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current amplifiesr for speakers now "degraded"?
"GregS" wrote in message
In article QlEYj.22113$sX5.5434@trnddc02, "Earl Kiosterud" wrote: "Arny Krueger" wrote in message . .. "Earl Kiosterud" wrote in message news:5eBYj.2858$dh.1900@trnddc05 "Arny Krueger" wrote in message ... (1) Many speakers are maybe 1/4 as efficient as AR2s (2) In the old days 95 dB was loud. These days 105 dB is not all that much for many people. 10 dB louder is 40 times the power. Do the math: 40 times 20 watts is 800 watts. For an increase of 10 dB, you need 10 times the power. Agreed. See point 2 above. Then see point 1, to see how I got to 40 times. Hey Arny, I failed to combine your 1/4 efficiency with your 10 dB difference. Now I see what you mean. 1/4 efficiency is a confusing term not normally used in reference to loudspeakers. It gives me a headache. I had a pair of 2's for a bit while, while I was rebuilding them. Whats the AR3 , about 83 dB ? That varies. The actual configuration of AR3s varied somewhat over the rather long life of the model designation. And that's not even talking about the AR3a which was a little more efficient. I did some google searching, and found 85 dB/w for the AR3. That of course depends on frequency. Efficiency decreased with increasing frequency for the AR3. I had a pair of AR3 woofers. I would put their efficiency at more like 88 dB/w. I remember a Klipsh add saying something like it takes 500 watts into an AR3 compared to 1 watt for the Klipshhorn. 500 = + 27 dB. Another reference put the efficiency of the Klipschorn at 104 dB/w. 104 - 85 = 19 dB. That equates to about 80 watts for the AR3 as compared to 1 watt for the Klipschorn. There are modern speakers running as low as 80 dB/w. Note that speaker efficiency is one of those specs that is very susceptible to specsmanship. You can tweak a crossover to give a few dB extra response at precisely the frequency you rate its efficiency. Efficiency is usually speced in the midrange either 400 Hz or 1 kHz, which for a 3 way speaker, may be in the range of the midrange driver, not the woofer. It's easy to make a midrange driver that is highly efficient. If you make the speaker sound just a little forward, you have just stepped up the speaker's specified efficiency, while providing impressive bass extension at the same old cost in efficiency. |
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