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Post subject: Speaker efficiency
Posted: Thu Feb 13, 2014 5:21 pm
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I thought this question remains a mystery for many and found this interesting article about dB value and actual power of an amplifier.

Enjoy!

http://tonereport.com/blogs/tone-tips/understanding-speaker-efficiency


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Post subject: Re: Speaker efficiency
Posted: Fri Feb 14, 2014 1:35 pm
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I don't know about this. That column seemed a little discombobulated ... Let's start off at the basics. A speaker converts electrical energy into sound pressure energy. Wattage ratings on speakers provide how much electrical power input they can take as an input. Period. Now, if you are going to have sound pressure dB "efficiency" ratings, it would need to be tied to a specific input wattage and also a specific frequency (e.g., this speaker produces X dB at Y watts for Z Hz). If you had that same spec between speakers, then you could compare the dB ratings between the speakers IF the "Y" and "Z" in their specs were the same. Anything other than that and you are comparing apples to oranges. Because of that ... to me ... you can't just say that a 100 dB speaker is twice as loud as a 97 dB speaker.

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Post subject: Re: Speaker efficiency
Posted: Fri Feb 14, 2014 1:49 pm
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One watt of input power measured at one meter is standard for speaker ratings (1W/1M). Based on that, a 100 db speaker is twice as loud as a 97 db speaker. The wattage rating of the speaker only has to do with how much power the speaker can handle and nothing to do with how loud it is.

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Post subject: Re: Speaker efficiency
Posted: Fri Feb 14, 2014 2:31 pm
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shimmilou wrote:
One watt of input power measured at one meter is standard for speaker ratings (1W/1M). Based on that, a 100 db speaker is twice as loud as a 97 db speaker. The wattage rating of the speaker only has to do with how much power the speaker can handle and nothing to do with how loud it is.


+1

Speaker manufacturers also seem to use the same 1000Hz tone for measuring SPL's that are standardized upon as the criterion for determining the static design impedance for a voice coil.

Arjay

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Post subject: Re: Speaker efficiency
Posted: Fri Feb 14, 2014 4:44 pm
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shimmilou wrote:
One watt of input power measured at one meter is standard for speaker ratings (1W/1M). Based on that, a 100 db speaker is twice as loud as a 97 db speaker. The wattage rating of the speaker only has to do with how much power the speaker can handle and nothing to do with how loud it is.


BZZZZTTTTTT

Wrong!

Shimmilou, you know better. :lol:

A speaker with a sensitivity rating of 107 dB is twice as loud as a 97 dB rated speaker. 3db greater in an amp is twice the power. 10 dB in a speaker is twice as loud. :D

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Last edited by bluesky636 on Fri Feb 14, 2014 4:52 pm, edited 2 times in total.

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Post subject: Re: Speaker efficiency
Posted: Fri Feb 14, 2014 4:48 pm
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01GT eibach wrote:
you can't just say that a 100 dB speaker is twice as loud as a 97 dB speaker.


Not only is your statement false, but that is not what the article says.

As Anthony Lucas from Eminence Speakers explains it, “You might even say that the more efficient speaker gives you more bang for your amp power and that it takes twice as much power to get the 100dB speaker to be as loud as the 103dB speaker. A 3dB gain is a doubling of power.”

Double the power (3 dB) does not double the loudness. It takes a 10 dB increase to do that.

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Post subject: Re: Speaker efficiency
Posted: Fri Feb 14, 2014 4:51 pm
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Retroverbial wrote:
shimmilou wrote:
One watt of input power measured at one meter is standard for speaker ratings (1W/1M). Based on that, a 100 db speaker is twice as loud as a 97 db speaker. The wattage rating of the speaker only has to do with how much power the speaker can handle and nothing to do with how loud it is.


+1

Speaker manufacturers also seem to use the same 1000Hz tone for measuring SPL's that are standardized upon as the criterion for determining the static design impedance for a voice coil.

Arjay


Yup. Most (but not all) speaker manufacturers measure speaker sensitivity as dB SPL at 1 watt/meter at 1000 hz. 1000 hz is used as it is in the most sensitive range of human hearing and is far enough away from the speaker resonance point to provide a consistent impedance.

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Post subject: Re: Speaker efficiency
Posted: Fri Feb 14, 2014 5:09 pm
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bluesky636 wrote:
Double the power (3 dB) does not double the loudness. It takes a 10 dB increase to do that.

dB is a logarithmic scale of sound pressure. And a measured 3 dB increase IS twice as loud (100 dB is twice as loud as 97 dB). What I was saying is that without uniformity in how these ratings are made and attained across manufacturers, it is very dubious (in my opinion) to make assumptions on which is louder (or more "efficient") given the same input.

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Post subject: Re: Speaker efficiency
Posted: Fri Feb 14, 2014 5:28 pm
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Beside the logarithmic scale and sound pressure, my interest is primarily in the practical side of the question.

Say, we have 2 same spec speakers, but one is 97dB and the other is 100dB.

And we also have a same amp for the testing. :lol:

The real question is how the same amp will act with each of the speakers in terms of how LOUD each (speaker) is?!?


:mrgreen:


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Post subject: Re: Speaker efficiency
Posted: Fri Feb 14, 2014 5:36 pm
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01GT eibach wrote:
bluesky636 wrote:
Double the power (3 dB) does not double the loudness. It takes a 10 dB increase to do that.

dB is a logarithmic scale of sound pressure. And a measured 3 dB increase IS twice as loud (100 dB is twice as loud as 97 dB). What I was saying is that without uniformity in how these ratings are made and attained across manufacturers, it is very dubious (in my opinion) to make assumptions on which is louder (or more "efficient") given the same input.


Sorry. But you are wrong. 50 watts to 100 watts (a 3 dB increase in power) is double the power. 100 dB SPL to 110 dB SPL (a 10 dB increase in SPL) is double the loudness. You need to do some more research.

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Post subject: Re: Speaker efficiency
Posted: Fri Feb 14, 2014 5:38 pm
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Nikola Tesla wrote:
Beside the logarithmic scale and sound pressure, my interest is primarily in the practical side of the question.

Say, we have 2 same spec speakers, but one is 97dB and the other is 100dB.

And we also have a same amp for the testing. :lol:

The real question is how the same amp will act with each of the speakers in terms of how LOUD each (speaker) is?!?


:mrgreen:


A 3 dB increase in SPL is noticeable but it is not double the loudness.

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Post subject: Re: Speaker efficiency
Posted: Fri Feb 14, 2014 6:09 pm
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bluesky636 wrote:
Sorry. But you are wrong ... 100 dB SPL to 110 dB SPL (a 10 dB increase in SPL) is double the loudness. You need to do some more research.

I don't agree. I think the problem is that correlations are being made between changes in electrical power (watts) and SPL changes (dB). I am not considering input wattages at all, and how much input power it took to make the 3 dB increase in SPL to occur. This is why -- as we all know -- a 100w amp is not twice as loud as a 50w amp.

So ... staying only in the SPL world for a minute, the math is pretty straightforward:

10 * log10 (2) = 3.01 dB, where 2 is the double in SPL (sound power)

If that is not right, then what am I missing?

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Post subject: Re: Speaker efficiency
Posted: Fri Feb 14, 2014 7:15 pm
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bluesky636 wrote:
shimmilou wrote:
One watt of input power measured at one meter is standard for speaker ratings (1W/1M). Based on that, a 100 db speaker is twice as loud as a 97 db speaker. The wattage rating of the speaker only has to do with how much power the speaker can handle and nothing to do with how loud it is.


BZZZZTTTTTT

Wrong!

Shimmilou, you know better. :lol:

A speaker with a sensitivity rating of 107 dB is twice as loud as a 97 dB rated speaker. 3db greater in an amp is twice the power. 10 dB in a speaker is twice as loud. :D


Duh! :oops: Yeah, I was thinking twice the power, but read and typed twice as loud. It takes about 10 times the power to be twice as loud.

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Post subject: Re: Speaker efficiency
Posted: Fri Feb 14, 2014 10:40 pm
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01GT eibach wrote:
bluesky636 wrote:
Sorry. But you are wrong ... 100 dB SPL to 110 dB SPL (a 10 dB increase in SPL) is double the loudness. You need to do some more research.

I don't agree. I think the problem is that correlations are being made between changes in electrical power (watts) and SPL changes (dB). I am not considering input wattages at all, and how much input power it took to make the 3 dB increase in SPL to occur. This is why -- as we all know -- a 100w amp is not twice as loud as a 50w amp.

So ... staying only in the SPL world for a minute, the math is pretty straightforward:

10 * log10 (2) = 3.01 dB, where 2 is the double in SPL (sound power)

If that is not right, then what am I missing?


Read all of this for a complete explanation:

http://www.sengpielaudio.com/calculator-levelchange.htm

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Post subject: Re: Speaker efficiency
Posted: Fri Feb 14, 2014 11:48 pm
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Don't forget Hoffmans Iron Law effect on speaker sensitivity , It considers speakers use and the architecture in which it's used . Not only power and inpedence but Cab design, size, grill cloth things that effect air moving. Speakers don't just sit there naked in the air :lol:
Feel like I'm on a HiFi/Stereo Forum where this is sometime discussed. :mrgreen:

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