Topic: speaker sensitivity

[dvdfan]

I am not seeing some questions regarding speaker sensitivity which is a very important factor in speaker and amp selection.

Which of the speaker will sound louder?

Speaker A with 100w @ 97dB sens. powered by 100w or Speaker B with 150w @ 85dB sens powered by 150w?

[manila]

I am not seeing some questions regarding speaker sensitivity which is a very important factor in speaker and amp selection.

Which of the speaker will sound louder?

Speaker A with 100w @ 97dB sens. powered by 100w or Speaker B with 150w @ 85dB sens powered by 150w?

DVDFAN,
    Hope I can shed some light. Given that everything remains constant like the room acoustics etc. We set out a set of rules. Doubling the power output of the amp results in a 3DB gain! The difference is 97DB-85DB=12DB diff! A 97DB sens speaker will definitely be audibly louder with a 100w than a 85DB speaker with 150w!
   To get the same Decibel output of a 97DB speaker/100w output  combo on a 85DB speaker, you need 1600w of amp power on a 85DB speaker to attain the same level of Decibels of the 97DB/100w power amp combo.

    Summary :

AMP POWER    
100w               85db
200w               88db
400w               91db
800w               94db
1600w             97db

     Unless we are bringing the house and the neighborhood down, one would suggest that a 100w amp running a 87db speaker should be sufficient for small to medium sized rooms unless you require a hearing aid!

Manila

[electronics-depot]

Manila,

The point here is that people are blinded by wattage. Which should not be the case when buying an amp and speaker. This explains why some speaker will sound louder on some amps because of sensitivity.

[dvdfan]

The 97dB and 85dB are just examples.

As you explained, you will need 1600w to for speaker B which is expensive and you will only need 100w for speaker A. Which will cost you a few thousands.

Manila, What is not constant in room acoustics?

[maximusmeridius]

How can one determine how loud a speaker can go before clipping (assuming enough current is fed into the speakers)? In the example given above, it just tells us how much power a speaker need in order to achieve a certain level of loudness.  But it does not really tell us how loud a speaker can go.  So how can one determine that?

Thanks.

[electronics-depot]

Clipping may be because of the power amplifier and for speakers it imay be called Distortion (I think).

There is usually a MAX SPL for loudspeaker and manufacturers do not recommend going above the MAX SPL.

The formula for pwer in dB is  10 log P2/P1. Where P1 is the reference power and P2 is the new new power.

For Example you have a loudspeaker with 111db @ 1w/m with rms rating of 100w.

10log(100/1) will be 131dB.

thanks.

[manila]

The 97dB and 85dB are just examples.

As you explained, you will need 1600w to for speaker B which is expensive and you will only need 100w for speaker A. Which will cost you a few thousands.

Manila, What is not constant in room acoustics?

DVDFAN,
   I understand those were just examples. 97DB and 85DB .

   What I mean by "everything constant" is a disclaimer which means everything is constant from the woofer locations of the two "sampled" speakers from the listening position, the distances etc.. There are so many other things that can alter the calculations. For example if your 85DB speaker sample were a bookshelf which goes down to 50hz and your 97DB is a floorstander which goes down to 22hz. If your room bumps the frequency around 40hz, then it will not be constant and the decibel readings will be different therefore I mentioned "everything constant" as a "disclaimer" so everything is kept constant between the 85DB vs the 97DB speaker. Hope this clears things.


N.B. Sensitivities are specifications using a designed anaechoic chamber and the speaker is suspended in the air at the manufacturers laboratory. Our rooms are not perfect and will have peaks and dips in the frequency therefore given that, the sensitivity will be altered room to room.  

Manila

[manila]

How can one determine how loud a speaker can go before clipping (assuming enough current is fed into the speakers)? In the example given above, it just tells us how much power a speaker need in order to achieve a certain level of loudness.  But it does not really tell us how loud a speaker can go.  So how can one determine that?

Thanks.

Maximus,
    Very good question and almost impossible to answer! MAXIMUM SPL's is almost impossible to attain unless you have a SPL meter and the gear that you wish to measure. There are many criteria in this field than just the maximum handling power of a speaker and an amps maximum RMS in watts. Just as an example, a high-end speaker like a Dynaudio Contour 1.3MKII, this is rated at 150w RMS handling power. But I have heard this being run by a Musical Fidelity NuVista M3 which pumps out 500+wattsx2 at 4ohms (the Dynas are 4 ohms speaker) and it really sings!
   Stereophile and other high end journal measures the amps maximum rated power (normally good quality amps far exceed it's rated power output in the measurement at clipping). Also, manufacturers rate their power rating at .1%THD some at .003%THD some at .001%THD therefore one really needs professional measuring equipments to find the Maximum attainable SPL between a speaker and it's powering amp. Theoretical calculations are inaccurate in this case. Just my 2 cents..

Manila

[dvdfan]

Is speaker sensitivity frequency dependent? Have you seen a manufacturer rating the sensitivity like 98db at 100hz, 95dB at 40 hz.  Or simply 95db at 1w/m. You may be confused with frequency response with loudspeaker sensitivity. Frequency response is simply shown as 10hz-18khz +/- 3dB or a graph of the response. Room interaction, room gain or room modes can easily be calculated and can be seen during tests and measurements so room does not matter in this case as we are only talking about the speaker. Real world test will Go back to the basics of physics.

Sensitivties of speaker are not tested in anachoeic chamber but rather in a reverberant chamber. Again, frequency response is tested in an anechoic chamber. But new technologies in measurements can filter out reflections via time domain so an anechoic chamber is not too popular these days.  It is what you usually see when a writer writes a review of a loudspeaker and shows you a graph.. They usually use TEF, LMS, MLSSA, etc...

The 97dB and 85dB are just examples.

As you explained, you will need 1600w to for speaker B which is expensive and you will only need 100w for speaker A. Which will cost you a few thousands.

Manila, What is not constant in room acoustics?

DVDFAN,
    I understand those were just examples. 97DB and 85DB .

    What I mean by "everything constant" is a disclaimer which means everything is constant from the woofer locations of the two "sampled" speakers from the listening position, the distances etc.. There are so many other things that can alter the calculations. For example if your 85DB speaker sample were a bookshelf which goes down to 50hz and your 97DB is a floorstander which goes down to 22hz. If your room bumps the frequency around 40hz, then it will not be constant and the decibel readings will be different therefore I mentioned "everything constant" as a "disclaimer" so everything is kept constant between the 85DB vs the 97DB speaker. Hope this clears things.


N.B. Sensitivities are specifications using a designed anaechoic chamber and the speaker is suspended in the air at the manufacturers laboratory. Our rooms are not perfect and will have peaks and dips in the frequency therefore given that, the sensitivity will be altered room to room.  

Manila

[dvdfan]

The formula in MAX SPL is an AES standard which is by the audio engineering society. This came to be via years of research and testing and became a standard because a lot of engineers approved of it. Of course they are just a guide and likewise not a 100% fool proof formula and may vary via a few dB. I will not argue with engineers who have studied this and have empirical data to prove it.

In your dynaudio example, what was the max. spl reached?I can use a 1200w amp on a 150 w speaker and it will sound great but then again, we are not talking about sensitivity but watts...

How can one determine how loud a speaker can go before clipping (assuming enough current is fed into the speakers)? In the example given above, it just tells us how much power a speaker need in order to achieve a certain level of loudness.  But it does not really tell us how loud a speaker can go.  So how can one determine that?

Thanks.

Maximus,
    Very good question and almost impossible to answer! MAXIMUM SPL's is almost impossible to attain unless you have a SPL meter and the gear that you wish to measure. There are many criteria in this field than just the maximum handling power of a speaker and an amps maximum RMS in watts. Just as an example, a high-end speaker like a Dynaudio Contour 1.3MKII, this is rated at 150w RMS handling power. But I have heard this being run by a Musical Fidelity NuVista M3 which pumps out 500+wattsx2 at 4ohms (the Dynas are 4 ohms speaker) and it really sings!
   Stereophile and other high end journal measures the amps maximum rated power (normally good quality amps far exceed it's rated power output in the measurement at clipping). Also, manufacturers rate their power rating at .1%THD some at .003%THD some at .001%THD therefore one really needs professional measuring equipments to find the Maximum attainable SPL between a speaker and it's powering amp. Theoretical calculations are inaccurate in this case. Just my 2 cents..

Manila

[manila]

The formula in MAX SPL is an AES standard which is by the audio engineering society. This came to be via years of research and testing and became a standard because a lot of engineers approved of it. Of course they are just a guide and likewise not a 100% fool proof formula and may vary via a few dB. I will not argue with engineers who have studied this and have empirical data to prove it.

In your dynaudio example, what was the max. spl reached?I can use a 1200w amp on a 150 w speaker and it will sound great but then again, we are not talking about sensitivity but watts...

DVDFAN,
   "Formula will vary via a few DB". My point taken that one cannot measure SPL by mere formulas alone, one needs professional measuring equipments due to variances within the equation. You can measure the max SPL in a 5ft by 10ft room room but what about a 20ft by 20ft room? Then the data will be altered. What about a 5ft by 5ft room with a solid cement surround compared to a 5ft by 5ft room surrounded by foam? What is the standard in measuring the MAX SPL given that you require the exact room dimension and properties? Also, varying by a few DB is alot because 3DB difference is doubling the "perceived" audible sound so if there is a difference of 2DB with the mathematical calculations and the "actual" measured MAX SPL, then as I have said it is inaccurate because a mere 2DB is audibly perceivable as louder.
    With Max SPL we are not talking about watts, WATTS is power. We are talking about Decibels which is the medium of perceived sound.
    In short, asking for the MAX SPL of a set of equipment is irrelevant as room properties plays a major role in MAX SPL. Should you get a MAX SPL value in your reverb room, it will have a totally different value in your "non treated or treated" 20ft by 18ft room.
    If you look at car audio, to gain the most Max SPL, they keep adding SUBWOOFERS! That adds oomph therefore SPL! They do not add 30 tweeters to gain more SPL. With home audio, a room that is untreated and "humps" +6DB at 50Hz will definitely have a higher SPL than a room which is "flat"! So frequencies also plays a major part in SPL. Cheers! I rest my case..

Manila

[dvdfan]

Manila,

What is being discussed here is the SPEAKER not the speaker with room interaction or room gain. The basis for the formula is based on a free field computation. Manufacturers give us the basic platform for their specifications and it is up to the user to decipher their room gain, absorption, resonance, etc... They will not give you data that are based on a 30cum room as it will be different in a 50 cum room with x% absorption coefficient, etc..

After getting the MAX SPL. There is also a formula so you'll know how much room gain you'll obtain based on the acoustic characteristics of your room.

Some manufacturer will even put MAX SPL 130dB measured in halfspace envirornment. Meaning that they measured the speakers with walls therefore a 6dB gain. In free field this is only 124dB.

A reverberant room is for RT60 and does not matter on SPL measurement.

If you ever wonder why a speaker sound better or louder in a room let us say Room A and sound bad on Room B. Science can tell you why and that is a proven fact. Otherwise there will be no acoustic engineers walking this earth.

Yes, SPL is frequency dependent and the formula applies to which driver you want to compute.




 

[electronics-depot]

yes, Manufacturers data or specs is adhered to the  AES standard of measurement. When they follow the AES standard, we, the consumers are protected in our buying decision so that we can compare specifications that are tested following the same procedure rather than the other testing it in a room with additional room gain.

Diifferent rooms have different acoustic characteristics and it is up to the user to know how it will sound in his room. No matter what kind of speaker he puts in his room he will experience the same acoustic characteristics. Whether its cancellation, peaks, reverberation, etc.. they remain constant unless the acoustic materials are changed. Therefore they are all constant and quantifiable.

Room modes can be computed to give you the peaks and dips of your room. Professionals simply run a waterfall plot to see the decay of the full frequency spectrum and will show which of the low frequency decays longer.

Speaker position and acoustic material selection can also be determined by running ETC (energy Time curve) and Ray tracing to show the reflections and time.

Frequency response of the speaker and sub can be determined to see if the sub and low interact in crossover points.

Hope this info helps how acoustic testing is done by experts and not be any tom, dick, and harry who will say so and so.....

[RU9]

Are there speakers with a sensitivity of 97db or above
available locally? (about 20k - 30k price range)

Thanks

[dvdfan]

Yes, you can buy at that price for each speaker but you will need a power amplifier to drive it. Those speakers are usually designed for clubs, bars, discos, concerts, etc.. and not for home theatre.. But I don't know if there is for HT.

[levi]

Reposting

Guys,

Can anybody help me about relating speaker sensitivity in matching it HT AVR.

Thanks....I really had a hard time figuring out this one...

prc

[levi]

Reposting

PRC,

Speaker sensitivity or sound pressure level (spl) shows the 'efficiency' of the speaker..generally, the higher the better..  a 88 db or higher means that the speaker is easy to drive by a modest amplifier.. lower than this, you need an amplifier with a higher wattage.. For example, if a 50 w amplifier can easily drive a 89 db speaker spl, it will take a 100w or twice the amount of power to drive a 86 db speaker..I recommend that you choose a speaker with a 88 db or above spl..if you already purchase a 86 db or lower spl of speaker, better shop for a high current amplifiers to drive them..

[levi]

Reposting

PRC,

It is important that you also consider impedance in conjunction with sensitivity.  The lower the impedance, the harder it is to drive.  

I read a thread here before where it discussed these matters including wattage ratings of speakers and how loud they can go.

Cheers.

[prc]

guys,

thank you for the insights......

cheers...

prc

[levi]

bump

[levi]

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[levi]

bump

[tuff_u_gong]

Are there speakers with a sensitivity of 97db or above
available locally? (about 20k - 30k price range)

Thanks

if you're open to horn-type speakers, check out
Klipsch (reference and synergy series) from studio systems,
AV surfer/AVID/Sony.

they're all rated above 93db.

some center speakers are rated 98db. i don't
know if they actually meet these specifications,
though, but they are definitely above 90db.

[markmlists]

What is the difference if any between:

86dB/2.83V/M
and
86dB/1W/M

Which is accurate? Which is louder?

Thanks.

[bumblebee]

Given 8 Ohms.

1 W=I^2*R
1 W=I^2*8
I=0.3536

E=IR
E=2.83V

Parang pinaikot lang.

As to w/c is louder, can't tell because different speakers have different impedance curves.

[markmlists]

Thanks..

[jerix]

I think professional speakers got higher sensitivity than most HT speakers.

Is there a way to lower or higher the sensitivity of the speakers? Got two of my speakers on series but the other one i think has higher sensitivity so it is always louder than the other. If there is a way, i want to balance them. 

[bumblebee]

I think professional speakers got higher sensitivity than most HT speakers.

Is there a way to lower or higher the sensitivity of the speakers? Got two of my speakers on series but the other one i think has higher sensitivity so it is always louder than the other. If there is a way, i want to balance them. 

Is the louder one, ported? Maybe covering the ports can help.

[jerix]

bro -- they are both ported -- ok ill just cover the port of the louder speaker. tnks 

[skylark]

ano po ba halaga ng sensitivity sa pag pili ng speaker if my reciever is only 80 watts ano speaker sensitivity kaya ng reciever ko ilang  maximum watts kaya ng reciever 

thank's po