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Can someone please explain the relationship between speaker size and watts.
I was looking at manufacturers sites and some models have the same size speakers but only half the wattage.
As an example:
4.7 inch speakers for 16 watts
and the same size speakers for 40 watts.
Is the 40 watts louder and will blow the speakers faster.
Ronald

Hey Ronald! Good question...

One of the things to consider when driving speakers with power is the more power behind a speaker, the better the dynamic range that the speaker will enjoy without "amplifier" distortion or overload. To often, people do not have powerful enough wattage in their amps to drive speakers. That is part of the reason that studio monitors will allocate an individual amp of 100 watts just for one 8 inch driver, etc. Buying studio monitors; in my opinion, is the best way to play a digital piano back since the drivers of the monitors have been matched with individual amps inside of the monitor. The engineers know how to match the correct power "into" a driver(s).

If the speaker is designed to handle the 40W, no, the 40W will not blow faster. A 16W speaker on a 40W amp will blow faster. A 40W speaker on a 16W amp would last forever.

Speaker size and watts...
Watts is a measure of power. Think of watts as heat.
A 16W 4.7" speaker is designed to dissipate 16W (probably a little more) while a 40W to dissipate 40W and will likely be made with better, more heat-tolerant parts.

Size does matter. Think of a 40W lightbulb. Hold it in your hands while it's on and you'll get burned pretty quickly. Put it in a something bigger like a shoebox and although the inside of the box will get warm, it won't burn your hand. It's much easier to dissipate a lot of power if the speaker's voice coil is bigger and the coil size is roughly related to speaker cone size so higher power speakers are generally bigger.

Is 40W louder? You mean is a 40W speaker louder than a 16W one? A 40W can be louder or softer. Given the same signal, it depends on the design and efficiency of the speaker. Actually, since a 40W speaker voice coil has to be heavier-duty than a 16W one, it's likely heavier which takes more energy to move so likely it'll be less efficient (quieter) than a 16W one.

A few more things...
Doubling the power to a speaker doesn't make it twice as loud, only just noticeably louder. To double the volume you need 10 times the power!

On the subject of power, I have a Yamaha StagePas 500, where the 500 means 500 watts. However, the electrical power rating - how much power the system draws - is much much less. Back in high school they taught us that power is power - it can't be created or lost, just converted to another form of power. So why is the Yamaha system rated at 500 watts while taking 100 watts of electricity to run it?

Thanks

I think the 500 watts refers to "peak" power draw or output. Normally the wattage used is much less. If you are referring to why the 100 watts used is converted into 500 peak RMS wattage, it is because step-up transformers boost the voltage from 100 volts to a higher voltage which in turn increases the wattage that the speakers are receiving (W = V x I, Wattage = Voltage times Amperage).

Google Ohms' Law to learn more about power/impedance/voltage/amperage to fully understand how power or wattage refers to Ohm's Law. Here is a link on how to establish the wattage a device will use: Ohm's Law Calculator

You would need to know the resistance a device creates but that is an entirely different post!

HWYStar, I'm not sure I understand your statement about the voltage being boosted from 100, but your point about peak / RMS vs steady state makes sense. Thanks

you left out "at the same power"

the efficiency spec will tell you how loud a speaker is with one watt of power.

a speaker with lower efficiency will be lower with one watt of power, but if it can handle more power overall, can ultimately play louder

another big variable, though, is cabinet design

The make of the speaker would also come into play. For instance. A set of pc speakers that are hooked to your computer right now. Have you ever compared different types and brands when getting a new set?

Depending on how well made the same spec speaker could sound muffled or distorted while a better made speaker sounds crisp and clear like guns are going off all around you in call of duty black ops.

Sound volume level is to product of speaker efficiency times power. But they speaker efficiency. They shouud because it can easy vary by a factor of 10 or more while power is always in a smaller range. I think the reason is that efficiency is expressed in units os "dB/W at 1 meter" and the average consummer has not a clue what a dB/W is.

The range is about mid 80's to about 100. A five W amp playig through a speaker rated at "80" would be hard to hearunless you were close. With a "100" speaker the neigbors would be calling the cops if it were to late.

Notice they never put frequency response or distortion levels in the specs either.

So what I'm saying is (1) they don't really give you enough information to figure anything out and (2) don't worry about watts unless one piano is way more than double the other. and (3) the one thing that matters the most is missing from the specs.

In the end none of the speakers in moderate priced ($2K or less) DPs are great, good enough for practice at home but if you are thinking about performance or just f=trying to replicate the sound of an acoustic piano then you will need an external sound system.

ChrisA:

I am going to be popping for some Genelec 8050A speakers (4) and a Genelec 7070A sub for my V-Piano. These should sound really nice at home or in small venues - right? We will be playing classical music so I am not looking for 115db SPL!

I think they have the power and clarity to do the job based upon talking to the Roland Rep about the speakers... God knows it will cost me enough but I won't need to upgrade for this piano or any other piano in the future!

"...step-up transformers boost the voltage from 100 volts to a higher voltage which in turn increases the wattage that the speakers are receiving"

No way... power is power. Amps typically use step-down transformers to reduce the wall's 120V to something the speakers can handle.
Power in = power out.
120V input at 1 Amp = 120W.
12V output at 10A = 120W (but will always be less because of inefficiency of the circuitry, namely production of heat).

If you've found a device that takes in 100W and outputs 500W all on its own then patent it, market it, and enjoy your new life as a billionaire. It just doesn't exist.

Back to the original question, that 500W output spec can't be 500W continuous RMS, otherwise it would have an input rating closer to 800W or more.

Well, that StagePas 500 must be one of those miracles, creating more power than it uses. Here is an excerpt from the brochure:

Output Power (Maximum) 250W+250W(10%)/4@10% THD at 1kHz (SPEAKERS L/R)
Output Power (RMS) 200W+200W/4@1% THD at 1kHz (SPEAKERS L/R)
Power Consumption 65W

I wonder if someone from Yamaha could help me out here.

D'oh! The 200 WPC spec is what the amp is capable of producing. If the specs are honest, then it can produce that continuously, per the rules set down in govt regulations.

But the amp puts out zero watts much of the time, and just a few watts most of the time. The 65 W power consumption spec is a typical/average value.

If and when the amp actually puts out 200 W, it will be consuming quite a bit more than 200 W ... and much more than the 65 W power consumption spec.

There is no magic.

An acoustic concert grand piano played "ff" is about 100dB. You can smack down hard on the keys and get it go over 100 but that is not normal playing. So you are right, you don't need 115dB.

If you need to move the speakers for gigs then you are pretty much forced to spend big $$$. But for home use you can get very good quality using home stereo speakers at $250 each and maybe another $250 for an amp but that style of gear would get beat up quickly.

I grew up reading the Hirsch-Houck reviews in Stereo Review. I learned from them how to read spec sheets and what to look for.

Thanks for the advice Chris!

Sorry about bumpng an old thread.

My DP came with two 10 centimetres speaker drives and the builtin amp can output 25w per channe.. I have connected them to my own amp which -according to the specs- can output 40w per channel. However, the sound is rather weak (also the body vibration) if I have the amp output at half and I'm worried that by gong beyond the DP's amp watts the speakers will be damaged in the mid to long run.

Is that for certain? How can I make sure it wouldn't happen?

Please describe how you connected your piano to the 40 watt amplifier.
Also, what speakers have you connected to that amplifier?

Well you know the story Mac: https://forum.pianoworld.com/ubbthre...xternal-amplifier-to-the-dp-speaker.html

.... what macmacmac said, and ....

be aware of somewhat unpredictable “peak” power transients conditions versus more typical steady state audio power consumption and also be aware of a rule of thumb that has served many well at least since the days when “ your grandfather’s hi-fi” morphed in junior’s foray into hooking up his first component equivalent: if your output load is, minimally, rated to handle as much power that the source is rated to provide , she’s less likely to blow.

Back then, many enthusiasts hedged this rule by installing speakers that could handle twice what the amp was capable of, IE. attach 50 to 100 watt speakers to an amp rated for 50 watts per channel ..... that generally sufficed back in the mostly-analog audio enthusiast’s world.

You have attached a DP’s 25 WPC amp line output to the input of (another) amp that outputs 40 WPC .... looks okay on paper.

Aside from reporting the rating of your speakers attached to amp #2, it may help for you to gradually try tweaking your DP’s line output volume at a moderate level and amp #2’s output volume accordingly to arrive at suitable volume output by the speakers which, if these are monitors, may also have their own hardware tweaks for input and output levels.

... what is this body vibration you speak of?