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I may add : If you consider the sound pressure written in Pa (Pascal), you need to multiply per 4 the power to double the pressure level. It is a quadratic relationship (the power is proportional with the square of the amplitude or sound pressure).

(But I have to admit Pa is less frequently used than dB about sound pressure levels).

What’s logarithmic is the way we hear. Bell Labs did experiments on human hearing in order to understand the requirements for telephony. They discovered that on average humans perceive a tenfold increase in SPL as a doubling of volume. So they invented a measurement system that would correspond roughly to human perception. The unit is the Bel. +1 Bel doubles volume. -1 Bel halves volume. The math to convert electrical and sound pressure to Bels is log10. Decibels (dB) are tenths of a Bel.

Some good rules of thumb for musicians are:

+3dB doubles power. This is noticeable, but is not significantly louder to our ears.

+10dB is ten times the power, but is perceived as doubling volume.

Good one, Charles.

I have a similar one that is OT here but regularly OnT with a lot of the elderly folks for whom i provide home care.... as the elderly often gradually lose mobility, they tend to accumulate piles of clutter in the two or three places in their homes where they spend most of their day and night IE. they want to pile up as much stuff as they can in the container on the table beside easy chair or beside the toilet or on the night stand beside bed .....somewhat logical but i often must remind them that they cannot expect to reliably house 10 pounds of stuff in a 5 pound container..... but this does not stop them from trying to do so ..... i think in part because their ears - SpL - dB function is on a similar track with their mobility.... i know, a transparent way of making it look like ive not strayed OT.

That's me and my night-table drawer !

and those are my wife's very words!<g>

I have an attic, and one day someone will have to clean it out . . .

Let me see if I have understood this correctly:

Lp = 20 log10(prms / pref)

assume (prms / pref)=10
then Lp= 20dB
if 10x the amp power (prms) then
(prms / pref) =100
Lp=40dB

Double the SPL rule is correct here.

Now if (prms / pref)=1000 then
Lp=60dB

It didn't double 40dB. But it would double if (prms / pref)=10000 i.e Lp=80dB

Is that what you meant?

@Sweelinck and others:
Thank you for the replies.Yeah the speaker wouldn't respond as well even if I could maximize the input volume, I think I've noticed that, the distortion seemed to increase.
So per the human ear and speaker driver health rules, my limit would be 80-85dB, given my current setup.

@Charles Cohen:
The Samsung app has its own set of bookshelf speakers - bigger than the DP's drivers- which I use for listening to music, as it's located on another desk at my ear level. I'd rather not further mess up the DP aesthetics by placing such "inconsistent" speakers underneath it. However, I might eventually end up doing just that!


Speakers: https://images.app.goo.gl/85u2eX3Ug2TxcExK9

You should be more precise about the meaning of the parameters. What is Lp ?

I guess pref, prms are powers (in Watt). In this case, you have

Power in dB = 10.log(prms/pref). Not 20….

The 20 in 20.log(A/Aref) appears when you use amplitudes (Pascal about sound level, Volt about electronic level).

If you put the speakers underneath the DP, you'll lose a lot of high-frequency sound.

In general, people try to keep outboard speakers at ear level (when playing), pointed toward their ears --

. . . and esthetics be damned!<g>

I was just thinking that -- if you get a pair of old hi-fi speakers -- you could put them at ear-level, at the piano. It would be easy to build a switch-box that would send the Samsung output to its own speakers, or to the hi-fi speakers at the piano.

Given what you have, and a tight budget, that might be your best "sound quality per $ spent".

As it is, much of the high-freq sound is lost already and the thought of adding a pair of twitters has crossed my mind a few times since I bought Pianoteq. The G1 Air has those tweeters but it does not warrant an upgrade I think.

As for a switch box, I have already done that, as pointed out before, to route sound through the DP's speakers or the Samsung speakers which are meant for music listening.

But I see where you're coming from.

Given my tight budget, the DP's decent speakers, and the high-freq loss issue which I'd say is the primary factor in sensing a lower volume, I have a few options:
a) Adding a pair of tweeters to compensate for the high-freq loss using the DP"s speakers.
This makes for a lower cost I believe, while gaining a higher perceived volume and quality. However I'm not even sure if it's doable.
b) Adding a new set of outboard ear-level speakers as you suggested.
This costs more in return for a potentially superior sound quality. I just checked second-hand prices and it costs at least as twice as a pair of fine "car" tweeters.
c) Use the Samsung's speakers, which come with tweeters and subwoofers. The drivers are slightly bigger than the DP's.
They do sound very good. However this approach destroys aesthetics, like the previous approach, while costing nothing.
d) Make do with the current setup until I lose satisfaction or the speakers. :-)

And yes, aesthetics counts. :p I like simplicity; And I'd just rather dismiss anything that takes away from the illusion of playing an acoustic piano, that is, as much as possible. I can't dismiss Pianoteq. :-)

You will need crossover circuits, and you will need to calculate or measure the impedance of the combined speaker to be sure it is within the impedance spec of the amp.

The lack of tweeters is unlikely to be why your volume is low.

What inputs does the Samsung stereo have?

It's complicated I see.

The lack of tweeters does make the general perception weaker than it really is.

The stereo has RCA input jacks.

I saw above your source is pianoteq on a PC routed to the amp in your Samsung music player.

Why aren't you just using the speakers of the Samsung unit instead of trying to wire the amp from that unit to the speakers in your piano?

Also, it appears that your piano may function as a powered bluetooth speaker (is it a Korg C1 Air?). If your laptop does not transmit bluetooth audio, a bluetooth audio transmitter like an Aluratek BT5 would cost about the same as a pair of tweeters. You could just stream pianoteq from the computer to the piano using bluetooth.