THE ALL CHANNELS DRIVEN FALLACY

[TLS Guy]

stand corrected

I admit loose use of terms. Of course I should have used the term sensitivity. However efficiency and sensitivity are closely related. A more sensitive speaker will give a greater sound output for the same input power, and is therefore the more efficient transducer.

 

[mtrycrafts]

I admit loose use of terms. Of course I should have used the term sensitivity. However efficiency and sensitivity are closely related. A more sensitive speaker will give a greater sound output for the same input power, and is therefore the more efficient transducer.

Efficiency is power in vs power out, no? Or, units in and units out of the same units.
Speaker sensitivity is power in and spl out, Watts and pressure so how are they closely related? Just curious.

http://www.crutchfieldadvisor.com/ISEO-rgbtcspd/learningcenter/car/speakers_glossary.html

 

[TLS Guy]

Efficiency and SPL

A more sensitive transducer will produce a higher spl than a less sensitive one with the same power consumed. In other words if you keep the power to two transducers constant, the more sensitive one will sound louder. More electrical energy will have been converted into to sound energy by the more sensitive transducer.

 

[annunaki]

Efficiency measures how much input power is turned into motion and/or output on a single driver and how much of the input power is wasted in heat. Most individual drivers are only about .25% to .35% efficient. Meaning 99.75%-99.65% of a given watt is wasted in heat.

Sensitivity measures how well the individual drivers coupled with the enclosure translate a given input signal into acoustical output.

I just thought I would put that out there for everyone so as to avoid confusion.

When one considers how much power is really in a single watt, one realizes how much energy is being wasted.

Here something that may put it into perspective.

760 watts = 1 horsepower

Say a person's sub handles 800 watts of power continuous. Using an efficiency number of .35% from above, of that signal, only 2.8 watts of power are being converted into acousical energy or motion. The other 797.20 watts are being wasted in heat and or being absorbed by the suspension and other losses. This is why you see big monster drivers and cooling systems. They have to deal with the heat.

If we could somehow improve the actual efficieny of individual drivers to say 20%, we could power our systems with as little as 10 watts of power AND reach very high spl's.

The 800 watt sub really would only need 2.8 watts of power to reach mind numbing spl levels if we could get efficiency of 100%. We would then not have to waste 1+ full horsepower in heat!

Putting all this in perspective, it is amazing how loud some of the systems out there can get with just one watt of input power (when thinking how much of the watt is being wasted in heat on each of the drivers) when coupled with an enclosure. Sensitivity is, in a way, a measurement of the efficiency of the driver & enclosure's (or system's) ability to turn input power into acoustical output.

Do not confuse individual driver sensitivity with a speaker system's (speaker enclosure, crossover, etc.) sensitivity however as they are fairly different.

I hope this makes some sense or is fairly relevant.

 

[Moo]

Your speakers are easy to drive. 200 watts would be overkill...

They have a nominal impedance of 8 Ohms and have a sensitivity of 88 db's (1 watt from 1 meter). 20 watts would make your Ref 3's go louder than your ears will want to hear in a room the size of yours.

The overall quality of the amplification matters more than anything. You can in theory use a Yamaha $350 receiver pumping out 100 watts per channel, but sonically, it won't compliment your speakers particularly well as your speakers will reveal the limitations of a budget receiver in a heartbeat.

Try an Integra DTR8.8. It (like any other receiver in it's price range) has far more power than your speakers demand, but it also has very high quality circuitry, high quality DACs, an excellent transformer and pre-pro approaching performance.

A nice tube amp with HT by-pass would work great with your speakers, such as a Prima Luna Dialogue 2.

 

[pmac]

I have a quetion sort of about this stuff<--the technical term
Based on your receivers volume, how do you know how many watts you are putting out, in order to not damage the speakers, because my amp I think supposedly outputs more than my speakers are rated for, or on the other side, to know if you can turn it up more without possibly damaging the speakers? I have a 3808 and som B&W 603's. I spent (for my budget) a lot of money on both and would like to turn this up more (especially after we move in a couple of weeks) but have the fear of doing damage. I guess clipping or disortiion would be an indicator, however isnt it possible that if you get to that point the damage could already be done?

Just curious if there is a way to tell or if the 0.0dB level is the rated output, i dont even know if the receiver will go farther than 0.0...Of course now that I typed that I checked and it will go to the positive side of the scale too (there was no source being input when cheking

 

[TLS Guy]

I have a quetion sort of about this stuff<--the technical term
Based on your receivers volume, how do you know how many watts you are putting out, in order to not damage the speakers, because my amp I think supposedly outputs more than my speakers are rated for, or on the other side, to know if you can turn it up more without possibly damaging the speakers? I have a 3808 and som B&W 603's. I spent (for my budget) a lot of money on both and would like to turn this up more (especially after we move in a couple of weeks) but have the fear of doing damage. I guess clipping or disortiion would be an indicator, however isnt it possible that if you get to that point the damage could already be done?

Just curious if there is a way to tell or if the 0.0dB level is the rated output, i dont even know if the receiver will go farther than 0.0...Of course now that I typed that I checked and it will go to the positive side of the scale too (there was no source being input when cheking

You can't tell how many watts you are putting out, and it varies moment by moment. It is the average power over time that matters, as that determines how much heat is generated in output stages and speaker voice coils.

Always play your rig at sensible levels. Playing at high continuous levels damages your hearing. Not only that, high power levels lead to premature output device failures in your receiver. Remember all solid state devices have a temperature/time longevity curve. So the longer and hotter you run them, the sooner they fail.

Now apparently your speakers are able to handle less continuous power than you receiver's maximum power output. Therefore if you play music with poor dynamic range, like rock music, at high power levels, you could burn out a speaker voice coil or two.

The bottom line is that of you are sensible with your equipment you most likely can enjoy it for many many years. If you drive it pedal to the metal expect short life and repair bills.

 

[eljr]

Response to posts 186 and 187 above.

Well, I got speakers who have "recommended power requirement" from 50 to 500 watts @ 8 ohms, got amps that are rated 500 watts each continuous power and then I sit back and watch the big beautiful blue meters that tell me how much power is being used.
Never worried.