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SPL, watts, speaker efficiency and distance Excel calculator


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I made a spreadsheet with a few calculations that help me understand efficiency, how watts relate to actual db gain, and how distance affects loudness.

 

You will find attached below, a compressed (zip) file containing this Excel spreadsheet.

 

gMRZv8Nl.jpg

Edited by mustang guy
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Mustang, one of my Bud's on another Forum throws some really strange unknown gear up all the time, this just came up today, i mean talk about great timing, you know you need a bigger Amp, and after you break them in sell them to me, you know at a discount.

The Pic comes with comment too :o

 

So how much are these Swedish beauties? Aye, there's the rub—The Lars Type 1 is a cool $110,000/pair, up 10 percent from last year due to the shifting relationship between the Swedish

 

 

post-57941-0-46700000-1431747417_thumb.j

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Okay, I need an opinion to confirm one of mine.  It is that some of our listening is when the amp is putting out a micro-watt.

 

When you look at this

 

http://en.wikipedia.org/wiki/Sound_pressure#Sound_pressure_level

 

A normal conversation level is at 40 to 60 dB.  For easy math, let me claim 45 dB and also claim that some classical music passages are like the level of conversation in our living room.

 

 Assume  a K-Horn, LS, and Belle are putting out 105 dB at one meter.  So, 45 dB acoustic output is 60 dB down from that 1 watt level.

 

By my calculations, the amplifier is putting out a micro-watt.

 

Agreed?

 

WMcD

 

 

 

 

 

So, let us say that some musical passages for classical music reproduction are at conversational levels.

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...

Now if someone can explain the difference to me between speaker sensitivity versus efficiency, in terms I can understand I would be most appreciative.

...

I always thought of them as the same thing. 

 

My LaScalas are efficient speakers because they are 104db at 1 meter with 1 watt

My LaScalas are sensitive to 1 watt of power in that they provide 104db from 1 meter away.

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Okay, I need an opinion to confirm one of mine.  It is that some of our listening is when the amp is putting out a micro-watt.

 

When you look at this

 

http://en.wikipedia.org/wiki/Sound_pressure#Sound_pressure_level

 

A normal conversation level is at 40 to 60 dB.  For easy math, let me claim 45 dB and also claim that some classical music passages are like the level of conversation in our living room.

 

 Assume  a K-Horn, LS, and Belle are putting out 105 dB at one meter.  So, 45 dB acoustic output is 60 dB down from that 1 watt level.

 

By my calculations, the amplifier is putting out a micro-watt.

 

Agreed?

 

WMcD

 

 

 

 

 

So, let us say that some musical passages for classical music reproduction are at conversational levels.

Yes, one microwatt at 1 meter. If you are sitting 20' away and the SPL is 45db, then it's more like 4 micriwatts. 3.98107E-05 to be precise.

 

I have updated the spreadsheet above to show more precision.

 

gMRZv8Nl.jpg

 

 

Edited by mustang guy
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All these claims on "high efficient" "high sensitivty" ... should there not be information on the test-signal that is applied ? (sine, pink-noise etc)

For example, my RF7-II's are "rated" about 98-100dB/W/meter.

 

If I apply a sinewave of 3kHz at 1W (which would be handled exclusively by the tweeter+horn) I can image obtaining such decent SPL at 1W

 

Howerver, if I apply a sinewave of 100Hz with 1W of energy, which is handled by the 10" woofers, I don't really think they are going to output 96dB at 1meter right ?

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I could save you some time, just ask me, id be happy to advise GET A BIGGER AMP(s)!

Nice spread sheet though.

 

LOL!  That's funny!  :lol:

 

"Not loud enough?  GET A BIGGER AMP!"

 

I have written, numerous times, that amplifiers should be rated in DB Watts. Zero DB Watts= 1 Watt, 10 DB Watts=10 Watts, 20 DB Watts=100 Watts, 30 DB Watts=1,000 watts.

 

I must add......................"Not loud enough?  Get more EFFICIENT speakers. If that won't do it, you then get a bigger amp."

 

If that won't do it, get your ears cleaned or tested!

Edited by ClaudeJ1
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I could save you some time, just ask me, id be happy to advise GET A BIGGER AMP(s)!

Nice spread sheet though.

 

LOL!  That's funny!  :lol:

 

"Not loud enough?  GET A BIGGER AMP!"

 

I have written, numerous times, that amplifiers should be rated in DB Watts. Zero DB Watts= 1 Watt, 10 DB Watts=10 Watts, 20 DB Watts=100 Watts, 30 DB Watts=1,000 watts.

 

I must add......................"Not loud enough?  Get more EFFICIENT speakers. If that won't do it, get a bigger amp."

 

If that won't do it, get your ears cleaned!

 

The wife requested MORE volume.

The wife wants to pizz off a neighbor.

What would you do ?

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I could save you some time, just ask me, id be happy to advise GET A BIGGER AMP(s)!

Nice spread sheet though.

 

LOL!  That's funny!  :lol:

 

"Not loud enough?  GET A BIGGER AMP!"

 

I have written, numerous times, that amplifiers should be rated in DB Watts. Zero DB Watts= 1 Watt, 10 DB Watts=10 Watts, 20 DB Watts=100 Watts, 30 DB Watts=1,000 watts.

 

I must add......................"Not loud enough?  Get more EFFICIENT speakers. If that won't do it, get a bigger amp."

 

If that won't do it, get your ears cleaned!

 

The wife requested MORE volume.

The wife wants to pizz off a neighbor.

What would you do ?

 

 

MORE volume: Buy her some new hair conditioner.

 

Pizz off neighbors: I would hide a speaker under a shrub under the neighbors window and put it on a timer to play dogs barking all night long. 

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Okay, I need an opinion to confirm one of mine.  It is that some of our listening is when the amp is putting out a micro-watt.

 

When you look at this

 

http://en.wikipedia.org/wiki/Sound_pressure#Sound_pressure_level

 

A normal conversation level is at 40 to 60 dB.  For easy math, let me claim 45 dB and also claim that some classical music passages are like the level of conversation in our living room.

 

 Assume  a K-Horn, LS, and Belle are putting out 105 dB at one meter.  So, 45 dB acoustic output is 60 dB down from that 1 watt level.

 

By my calculations, the amplifier is putting out a micro-watt.

 

Agreed?

 

WMcD

 

 

 

 

 

So, let us say that some musical passages for classical music reproduction are at conversational levels.

Any power level below 1 watt, which is 0 dbW and "the reference," gets a minus sign. So 1 Milliwatt is -30 dbW. A Micro watt would be -60 dbW. In reality, you may be looking at -50 dbW because there is a 10 db distance attenuation at 12 feet or so from the speakers.

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Using the "dBW" sure makes it easier to understand the relationship of watts to SPL.

Yes, and the marketing departments would never allow it because it would be hard to sell high power amps to horn lovers. Also, since Signal to Noise ratio figures are always relateive to full output, the smaller power amps are better performers because Khorns and the like work in the Milliwatt (-30 dbW) range typically in a home.

 

I measured my K402 section at 10 Milliwatts for 85 db at my sweet spot with pink noise. My Quarter Pies required about 4 dbW more than that for natural sounding bass because their sensitivity was NOT at 110 db. like the mid horn.

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"I know how to use my legs (so I don't need a car)."

 

Not the same, is it?

 

A car can get me across town faster than my legs, but the calculator is faster than trying to use the spreadsheet.

 

Do you remember the speed tests for the first calculators (for use in banking), the abacus won, hands down.
 

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