92db vs. 89db

[Hard 21]

On Wikipedia, there's an article with an example using sensitivity/efficiency of speakers with 92db/watt (actually 2.83V) @ 1meter vs. 89....

It repeatedly states that this 3 db difference is double the sound pressure. I assume the article is correct but it sure isn't what one would think. It stated that the 1st speaker was a 100 watt speaker and the 2nd was a 200 watt speaker and that if both we powered a 100 watts the 92db speaker would be twice as loud, and that the Nevermind here's the paragraph: t should be noted that a higher power rated driver will not necessarily
be louder than a lower rated one. In the examples which follow, it is
implicit that the drivers being compared have the same impedance. For
the first example, a speaker 3 dB more sensitive than another will
produce double the sound pressure level (or be 3 dB louder) for the
same power. Thus a 100 W speaker ("A") rated at 92 dB for 1 W @ 1 m
sensitivity will be twice as loud as a 200 W speaker ("B") rated at 89
dB for 1 W @ 1 m when both are driven with 100 W of input power. For
this particular example, when driven at 100 W, speaker A will produce
the same SPL, or loudness, speaker B would produce with 200 W input.
Thus a 3 dB increase in sensitivity of the speaker means that it will
need half the amplifier power to achieve a given SPL, and this
translates into a smaller, less complex, power amplifier and, often, to
some cost savings.

The biggest thing I'm confused about is that my receiver is 100 Watts/channel (115 in two channel). If I was using 100 Watt it seems like with my RF-35s rated at 98dbs that the spl would be 9800dbs. I know this is incorrect. In the example above 100watts seems like it'd equal 9200db vs. 8900 which is definitely not just half. When my receiver is on, is it always at 100 watts like a 100 watt lightbulb is and then maybe at 0db on the volume control one could make a pretty good guess of what the spl should be? A little insight would be much appreciated.

[Guest " "]

it would actually be 109 db. Assuming 2 speakers, listening position 12 feet from the speakers, you max power of 100 watts and speaker sensitivity of 98db.

Look at this link and play with the settings that represent your actual room. You might come out with different numbers. But this link helps understand the concept.

http://www.myhometheater.homestead.com/splcalculator.html

SPL CALCULATOR Speaker Sensitivity: dB SPL (1 W/1 M) Amplifier Power: Watts Distance: feet No. of Speakers: usually 2, more for multi-channel Speaker Placement (Choose 1): Away from walls (or do not consider placement) Near a wall (within 2 to 4 feet) In a corner (within 18 to 24 inches) RESULTS dB Gain from amplifier dB Loss due to dispersion (distance) dB Gain from sonic reinforcement (multi speakers) db Gain from placement (reinforcement from reflected sound) dB SPL at listening postion

[wuzzzer]

That article is 50/50 as far as correct/incorrect. Generally a 10 decibel difference is said to be twice as loud.

Generally, each time you double the wattage that a speaker will see a 3 decibel increase will occur.

Your receiver is not always putting out 100 watts. Most people using Klipsch speakers are probably using 5-25% of the total output capability of their amplifiers at any given time.

Your RF-35s will output 98 decibels with 1 watt of input, 101 decibels with 2 watts, 104 decibels with 4 watts, 107 watts with 8 watts, 110 decibels with 16 watts, 110 decibels with 32 watts, 113 decibels with 64 watts, 117 decibels with 128 watts.

By comparison, a speaker that is 89 decibel sensitive would output 89 decibels with 1 watt, 92 db with 2 watts, 95 db with 4 watts, 97 db with 8 watts, 100 db with 16 watts, 103 db with 32 watts, 106 db with 64 watts, 109 db with 128 watts, 112 db with 256 watts, 115 db with 512 watts, 118 db with 1024 watts.

So your speakers need 128 watts to put out 117 decibels, and an 89 decibel sensitive speaker needs around 1000.

[Hard 21]

Thanks for the replies.

So how in the world do I know how many watts my receiver is putting out? I think my manual informs me not to go above 0 on the volume dial. I'm assuming that is problably like the SPL that would get close to the calculator link?

[Guest " "]

Thanks for the replies.

So how in the world do I know how many watts my receiver is putting out? I think my manual informs me not to go above 0 on the volume dial. I'm assuming that is problably like the SPL that would get close to the calculator link?

I saw that question coming....the answer will require the use of another calculator.

http://www.angelfire.com/pa/baconbacon/page2.html

Use an ac ditigal voltmeter and measure the ac voltage at either your amp speaker terminals or your speaker terminals. Fill in the know info at the link, and your power usage will be indicated. Careful not to short out the leads of the probes.

You can also buy a speaker power level indicator from parts express for about 20 bucks each.

[Jay481985]

Technically the article is right..... every 3 db increase is double the sound pressure. But our ears percieve 10 db to double the sound pressure. Also the wattage is correct.

[wstrickland1]

you're missing the song man. just turn it up and enjoy.

[colterphoto1]

[in Lemmy accent] ' well, it's three more, innit?'

[cmdridq]

Remember the guitar amp that was louder cause it went to 11?