gement81 Posted September 2, 2004 Share Posted September 2, 2004 db/1 watt @ 1 meter vs db/2.3 volts @ 1 meter? Which one is more sensitive? I was trying to compare the specs of my CF-1's vs the RF-35's and I am having a real hard time understanding which speakers are better. They both have sensitivity specs with different units. Would someone please care to elaborate on this and help me decipher these specs. Quote Link to comment Share on other sites More sharing options...
Trooper Posted September 2, 2004 Share Posted September 2, 2004 ---------------- On 9/2/2004 8:52:46 AM gement81 wrote: db/1 watt @ 1 meter vs db/2.3 volts @ 1 meter? Which one is more sensitive? I was trying to compare the specs of my CF-1's vs the RF-35's and I am having a real hard time understanding which speakers are better. They both have sensitivity specs with different units. Would someone please care to elaborate on this and help me decipher these specs. ---------------- If it's an 8 ohm speaker then 1 watt equals 2.82 volts. That should give you a better apples to apples comparison. BTW, higher efficieny doesn't necessarily mean "better". Quote Link to comment Share on other sites More sharing options...
Ray Garrison Posted September 2, 2004 Share Posted September 2, 2004 Without knowing a lot about the characteristics of the speakers in questionm, it is hard to compare the two specs head to head. When you talk about a speakers sensitivity, you are talking about how loudly will a given speaker play given a specific input. Measuring the input going to the speaker is not nearly as simple as you might think. If we are measuring the power we are putting into a simple resistor, it's pretty easy. Say the resistor measures exactly 8 ohms. If we take an amp, play a 1 kHz sine wave through it, and set the signal level to 2.83 volts, we are putting exactly one watt into the resistor (power equals voltage squared divided by resistance.) If we had a speaker whose impedence measured exactly 8 ohms at all frequencies under all conditions, we measured the speakers output level with an input signal of exactly 2.83 volts, we could say "This speaker produces nnn dB with a 1 watt input signal under these conditions" or we could say "This speaker produces nnn dB with a 2.83 volt input signal under these conditions" and they would be completely analogous. However, the impedence of a speaker typically varies all over the place. In extreme cases, you might see 30 or 40 ohms at some frequency, and something less than 2 or 3 ohms at other frequencies. Under these conditions, it's a lot easier to measure the output when you supply a signal with a fixed voltage that it is to try and figure out exactly what power level the speaker is seeing. In addition to this, if you build speakers that are very hard to drive, from a marketing perspective it sounds better to use the voltage spec rather than the "1 watt" spec. For example, take the Apogee Scintilla, which had an impedence of .83 ohms at certain frequencies. If you input a signal of 2.83 volts and measure the output, you could say "This speaker plays at nnn dB with a 2.83 volt input" and it would look like you were comparing head to head with other speakers using a "1 watt input" spec. However, your Scintilla is actually drawing almost 10 watts from your amp, due to the very low impedence. So if the Scintilla is playing at, say, 86 dB at 2.83 volts at one meter, it would actually play at about 76dB with 1 *WATT* at one meter. Which spec would you rather publish? Quote Link to comment Share on other sites More sharing options...
Klipsch Employees Trey Cannon Posted September 2, 2004 Klipsch Employees Share Posted September 2, 2004 Ray, Very good statement. All true. FYI: When we set the sensitivity specks for a speaker we use Pink Noise ran into a 6db +/- crest limiter and then into a amp. We connect a load resister and set the Voltage to 2.83V (or as close as we can get) using a RMS Volt meter. Then we connect to the speakers under test and read the spl received at the mic. Quote Link to comment Share on other sites More sharing options...
Klipsch Employees Trey Cannon Posted September 2, 2004 Klipsch Employees Share Posted September 2, 2004 Oh yea, it is said that most folks that buy speakers "know" the word Watts when talking about audio, where as not all equate Volts with audio. SO the word Watts is used in 1watt/1 meter where 2.83V/1 meter is more correct. Quote Link to comment Share on other sites More sharing options...
gement81 Posted September 2, 2004 Author Share Posted September 2, 2004 Trey, any personal comments on subjective thoughts about the CF-1 vs the RF-35's? Quote Link to comment Share on other sites More sharing options...
colterphoto1 Posted September 2, 2004 Share Posted September 2, 2004 I much prefer the old 'Lirpa' tests in Stereo Review magazine. THey once had an ERC, the Elastic Rebound Characteristic of phono cartridges, which was measured thusly: Hold the phono cartridge (disconnnect from phonograph first) at arm's length, one metre above a one inch thick marble slab. Have a friend with measuring device nearby. Drop the cartridge onto the marble slab and measure the first bounce in inches or Centimetres. This is the ERC of the phono cartridge. NOTE: this post is strictly for entertainment purposes. Do not attempt this at home as equipment damage will surely result and the measurement is meaningless. Michael Quote Link to comment Share on other sites More sharing options...
Ray Garrison Posted September 2, 2004 Share Posted September 2, 2004 Lirpa Labs was in Audio Magazine, not Stereo Review. Quote Link to comment Share on other sites More sharing options...
Klipsch Employees Trey Cannon Posted September 4, 2004 Klipsch Employees Share Posted September 4, 2004 Only a few...THey are TOTAL DIFFERENT SPEAKERS. The CF-1 horn sounds nothing like the RF-35 horn...both good but different. I cant say which I like best...have not had enough time with them. Quote Link to comment Share on other sites More sharing options...
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