Speaker wattage: discuss

[pHEnomIC]

Can anyone please explain to me exactly how wattage factors into speakers?

I just don't understand how car speakers can use 300+ watts, and subs goin into the thousands of watts, and what is the point. Ive heard old school floorstanding speakers that can get mind numbingly loud with 5 watts!

Also it seems that people prefer the higher wattage speakers. What makes a higher wattage speaker better? I would think being less efficient would be a bad thing.

 

[deadguy99]

Wattage is only 1 of 3 main things that end up with the final result of the loudness you hear .. but generally speaking 90% of car speakers arent designed for high quality reproduction of music cause the variables involved are mind numbing to say the least and generally subs that go 1000's of watts sound like ass and tones are barely audible .. they usually use 3+inch voice coils designed for nothing more than rattling the body of the car and setting off car alarms .. they don't actually sound good at all

 

[Uncle Erik]

Quote:

Originally Posted by pHEnomIC /img/forum/go_quote.gif Can anyone please explain to me exactly how wattage factors into speakers? I just don't understand how car speakers can use 300+ watts, and subs goin into the thousands of watts, and what is the point. Ive heard old school floorstanding speakers that can get mind numbingly loud with 5 watts! Also it seems that people prefer the higher wattage speakers. What makes a higher wattage speaker better? I would think being less efficient would be a bad thing.

You bring up a lot of good points. For the most part, Watts are marketing. The majority of consumers believe that more Watts equals more quality. That's why the rating is always featured on the box and cited in ads.

For speakers, the amount of power handling tells you how much power it can handle without overheating and melting the insulation on the voicecoil, shorting it out. That has a relationship to how loud they'll get, but that's not everything. You can get a Klipschhorn to ear damaging levels from a few Watts. Klipsch speakers are great, and they're highly efficient. So are Lowthers. On the other side, ribbons are holy hell on an amplifier, but they sound amazing. There are a bunch of considerations when you consider power ratings for speakers, but there's a lot of design issues involved that I don't understand.

Take the Watt ratings of consumer amps with a grain of salt. There are no set standards for testing Watts so they play all sorts of tricks. The amp might hit 300W (or whatever) for two seconds while cooled to 20 below zero. Seriously, they do this. The amp might put out 60W at room temperature, but they can claim the higher Wattage under circumstances they won't put in 72 point type on the box.

 

[Clutz]

Different manufacturers are using different standards for rating their speakers. High quality speaker manufacturers use RMS wattage ratings. The other rating is typicaly PMPO- peak music power output- it's the maximum instantaneous power handling rating of the speaker, and they're ridiculous and have no strictly important meaning. If you want to compare watts to watts, you need to know their RMS handling.

 

[-=Germania=-]

Yeah,

I have never gone beyond halfway on my volume of my amp (30W RMS per channel) into my 90db full range speakers.

Truthfully, I can drive them prety great on about 5W for my listening levels.

30 true clean watts or RMS is going to blow the 900W PTP to the next century in loudness and clarity. The truth is that your standard 3 way speaker isn't going tp need more than 50W/channel ever anyway.....unless you liek ear bleeds.

Sensitivity and resistance also matter. A 4 ohm, 94db load will likely need not much RMS, but it will need an amp that can handle 4 ohms.

 

[m1abrams]

As Uncle Erik said the Max Wattage Rating on speakers is pretty much just marketing junk. You will be hard pressed to damage most speakers with too much PROPER wattage. Usually the problem with blown speakers is powering them with under powered amps and driving them to extreme clipping. I could blow that 1000watt sub with a 5W amp in no time. Yes driving a little 4inch fullrange with a 1000watt amp might push it beyond its limits if you send it full power but most sane people would not turn the volume up that high.

Sum it up the wattage rating on speakers is pointless.

 

[marvin]

Sound intensity (measured in decibels) and power (measured in watts) in a speaker system do not have a linear relationship. To get a 3 dB increase in sound intensity, you need to double the wattage. In a speaker system, the connection between sound intensity and power is the speaker sensitivity, which is measured in decibels/watt/meter. The meter term accounts for the distance away from the speaker as sound intensity halves when distance doubles. Total power handling, how much you power you can put into the speaker before it is destroyed, is a completely different metric and has little relation to sound intensity in hi-fi settings.

Two examples:

Joe has a hi-fi stereo system with high efficiency speakers (100 dB/watt/meter per speaker, 100W max) in a dedicated setup where he sits fairly close to his speakers (2 meters). Unforunately, Joe has bad taste in music and generally listens to low dynamic range modern pop/rock/rap (average volume is -6 dBFS).

Sarah has a modern space efficient stereo sub-sat system (85 dB/watt/meter per speaker, 200W max) in a setup where she sits at tv viewing distance away from her speakers (4 meters). Sarah mainly listens to classical and jazz recordings (average volume is -15 dBFS).

Both listen at a responsible level (88 dB average volume).

In this example, Joe's speaker system needs a meager 0.25 watts/channel to get his music not to distort. Sarah's speaker system needs a whopping 128 watts/channel to do the same. This is why amplifier power levels can be important. It can allow for high dynamic range and compensate for distance and/or inefficient speakers. In Joe's case, the fact that his speakers can take up to 100W doesn't matter. His listening habits don't require anything near that much. Sarah is a different case. Since her system needs so much power in order to avoid clipping, max power handling is a big issue. If her speakers could only handle 100W like Joe's, she'd have an issue on her hands.

As far as car subwoofer power levels go, look at an equal loudness curve. The ear is very effective at discriminating against low pitched sounds, so making subwoofer loud enough to sound loud requires a whole lot more power (something like 20-30x more) given comparable efficiencies between the subwoofer and other speakers.

 

[logwed]

Quote:

Originally Posted by deadguy99 /img/forum/go_quote.gif are mind numbing to say the least and generally subs that go 1000's of watts sound like ass and tones are barely audible ..

Very vivid image going through my head right now... sphincter-based diaphragms. They'll blow electrostats right out of the water!

 

[10068]

@logwed... gross. lol. I like it

re: Ohms.... would 4ohm or 8ohm output "sound better"? my integrated amp supports both; it has a toggle switch.

 

[m1abrams]

Quote:

Originally Posted by Sduibek /img/forum/go_quote.gif @logwed... gross. lol. I like it re: Ohms.... would 4ohm or 8ohm output "sound better"? my integrated amp supports both; it has a toggle switch.

Well generally the difference here is the damping factor, higher being better. Given the same amp and you double the Zload then you in effect double the damping factor. So 8ohm would be preferred. However and 8ohm speaker will require a higher voltage swing to get the same power output.

 

[10068]

Define voltage swing, Zload and power output please

I can get them plenty loud at 8ohms, the digital volume display is based on -0.00dB so even at about -50dB they are very loud.

 

[m1abrams]

Zload is the your load impedance (i.e. the speakers).

Basically since your amp can provide more than enough power for your taste you would be better off with an 8ohm speaker ALL ELSE BEING EQUAL. Note though a crappy 8ohm speaker is not better than a decent 4ohm one. Just that all else being equal an amp will have more control (better damping factor) over an higher impedance load.

4ohm speakers and lower are common in car stereo's where quality is not as important as volume AND that it is harder to make a power supply that can provide a high enough voltage rail from a 12V DC source to sufficiently power an 8ohm speaker.

 

[iriverdude]

Quote:

Originally Posted by Sduibek /img/forum/go_quote.gif Define voltage swing, Zload and power output please I can get them plenty loud at 8ohms, the digital volume display is based on -0.00dB so even at about -50dB they are very loud.

Speakers of different impedance would not alter "how loud" from one to another, one a amp's same setting. But the 4Ohm speaker is harder to drive, requiring more current from the power supply. You're confusing that with sensivity, in which case a speaker with lower sensivitity will indeed be quieter at the same setting compared to high sensivitity speakers such as horns.