Welcome to the Piano World Piano Forums
Over 2.7 million posts about pianos, digital pianos, and all types of keyboard instruments
Join the World's Largest Community of Piano Lovers (it's free)
It's Fun to Play the Piano ... Please Pass It On!

SEARCH
Piano Forums & Piano World
(ad)
Piano Life Saver - Dampp Chaser
Dampp Chaser Piano Life Saver
What's Hot!!
Mr. PianoWorld - the full interview
-------------------
European Tour for Piano Lovers
JOIN US FOR THE TOUR!
--------------------
Posting Pictures on the Forums
-------------------
Forums RULES & HELP
-------------------
ADVERTISE on Piano World
Find a Professional
Our Classified Ads
Find Piano Professionals-

*Piano Dealers - Piano Stores
*Piano Tuners
*Piano Teachers
*Piano Movers
*Piano Restorations
*Piano Manufacturers

Advertise on Piano World

(ad)
Piano Buyer Guide
Piano Buyer Spring 2018
ad
Pierce Piano Atlas


Who's Online Now
58 registered members (cfrederi, CyberGene, bennevis, beeboss, Beemer, cathryn999, chen, David B, 16 invisible), 1,127 guests, and 6 spiders.
Key: Admin, Global Mod, Mod
(ad)
Estonia Pianos
Estonia Pianos
Quick Links to Useful Piano & Music Resources
Quick Links:
*Advertise On Piano World
*Free Piano Newsletter
*Online Piano Recitals
*Piano Recitals Index
*Piano & Music Accessories
*Live Piano Venues
*Music School Listings
* Buying a Piano
*Buying A Acoustic Piano
*Buying a Digital Piano
*Pianos for Sale
*Sell Your Piano
*How Old is My Piano?
*Directory/Site Map
*Virtual Piano
*Music Word Search
*Piano Videos
*Virtual Piano Chords & Scales
Previous Thread
Next Thread
Print Thread
Page 2 of 2 1 2
Re: How much low frequency power does a piano have? [Re: MacMacMac] #2647640
05/27/17 02:31 PM
05/27/17 02:31 PM
Joined: Nov 2013
Posts: 4,090
Southwestern Ontario
P
prout Offline
4000 Post Club Member
prout  Offline
4000 Post Club Member
P

Joined: Nov 2013
Posts: 4,090
Southwestern Ontario
Originally Posted by MacMacMac
I don't understand what part of your earlier statement you're taking back.
Originally Posted by prout
I must sincerely apologize to PW for my contribution to mis-information. The addition of sine waves, as shown by the video posted by PianoMan51, is indeed accurate. My own tests using the technique shown in the video produce the same results. The octave below (missing fundamental) is clearly heard on my headphones.
If you linearly add pure sine waves at frequencies 2f, 3f, 4f, 5f, etc, the result contains NO energy at 1f. This is what I think you said earlier, and it remains true. So what exactly are you retracting?

If one does find some output energy at 1f, it's because either:
(a) the original sine wave sources were impure, containing some energy at 1f
or
(b) the mixing was non-linear, and the non-linear mixer products have produced harmonic and intermodulation distortion, some of which will be at 1f

But I don't think you intended to introduce these anomalies into the discussion. So wuzzup with the retraction?


The graphs in my first post showed sine waves at multiples of 130Hz, which explains why the resulting waveform had no peaks at 65Hz. My lastest graphs show sines at multiples of 60Hz starting at 120Hz, which obviously converge on a peak at 60Hz, which is what the video shows, even though there is still no energy at the fundamental in spite of there being peaks at the fundamental.

You, Frédéric L and I are all saying that there is no energy at the fundamental produced simply by the addition of sine waves that are multiples of the fundamental. What we hear is the result of a non-linear system, either in our ears or in the audio equipment or both.

That being said, my piano produces A0 24dB down from the peak partial, as can be seen on my posted image, so there is still audible, if weak, energy at the fundamental. I can sense it, but don't think a sub is necessary to reproduce it on a DP.

(ad) ROLAND

Click Here

Re: How much low frequency power does a piano have? [Re: prout] #2647649
05/27/17 02:49 PM
05/27/17 02:49 PM
Joined: Sep 2009
Posts: 6,838
Raleigh, North Carolina
MacMacMac Offline
6000 Post Club Member
MacMacMac  Offline
6000 Post Club Member

Joined: Sep 2009
Posts: 6,838
Raleigh, North Carolina
Here's where I'm losing you. I don't understand this "convergence" ...
Originally Posted by prout
My lastest graphs show sines at multiples of 60Hz starting at 120Hz, which obviously converge on a peak at 60Hz, which is what the video shows, even though there is still no energy at the fundamental in spite of there being peaks at the fundamental.

Re: How much low frequency power does a piano have? [Re: prout] #2647663
05/27/17 03:38 PM
05/27/17 03:38 PM
Joined: Oct 2013
Posts: 1,694
France
Frédéric L Online content
1000 Post Club Member
Frédéric L  Online Content
1000 Post Club Member

Joined: Oct 2013
Posts: 1,694
France
Originally Posted by prout
You, Frédéric L and I are all saying that there is no energy at the fundamental produced simply by the addition of sine waves that are multiples of the fundamental. What we hear is the result of a non-linear system, either in our ears or in the audio equipment or both.

That being said, my piano produces A0 24dB down from the peak partial, as can be seen on my posted image, so there is still audible, if weak, energy at the fundamental. I can sense it, but don't think a sub is necessary to reproduce it on a DP.


I don't think the illusion is about a non-linearity of the ear. An inner hair cell of our ear has no reason to vibrate at 1f if we have 2f, 3f... frequencies. I think it is about the way our neurons are connected. It is expected that when we ear a 3f 4f 5f frequencies, the "1f" neuron is connected to the 3f 4f 5f neurons and the addition of all the signals stress the first neuron. I think it is expected that related frequencies neurons are connected in order to sum-up what we ear.

-

When we read https://nanohub.org/resources/18884/download/2013.06.19-Giordano-REU.pdf page 17... we can't recognise the -24dB fundamental at 1f. We only found a -40dB noise at 1f. Here, the frequency is realy missing.


Yamaha CLP150, Bechstein Digital Grand, Garritan CFX, Ivory II pianos, Galaxy pianos, EWQL Pianos, Native-Instrument The Definitive Piano Collection, Soniccouture Hammersmith, Truekeys, Pianoteq
Re: How much low frequency power does a piano have? [Re: MacMacMac] #2647666
05/27/17 04:03 PM
05/27/17 04:03 PM
Joined: Nov 2013
Posts: 4,090
Southwestern Ontario
P
prout Offline
4000 Post Club Member
prout  Offline
4000 Post Club Member
P

Joined: Nov 2013
Posts: 4,090
Southwestern Ontario
Originally Posted by MacMacMac
Here's where I'm losing you. I don't understand this "convergence" ...
Originally Posted by prout
My lastest graphs show sines at multiples of 60Hz starting at 120Hz, which obviously converge on a peak at 60Hz, which is what the video shows, even though there is still no energy at the fundamental in spite of there being peaks at the fundamental.


Poor choice of words on my part. The video shows, as each succeeding partial is added to the previous partials, the peak amplitude of the 'missing fundamental' increases as did my own tests.

(ad) SWEETWATER
Easy Monthly Payments on Keyboards and Synthesizers
Re: How much low frequency power does a piano have? [Re: Frédéric L] #2647679
05/27/17 05:10 PM
05/27/17 05:10 PM
Joined: Nov 2013
Posts: 4,090
Southwestern Ontario
P
prout Offline
4000 Post Club Member
prout  Offline
4000 Post Club Member
P

Joined: Nov 2013
Posts: 4,090
Southwestern Ontario
Originally Posted by Frédéric L
Originally Posted by prout
You, Frédéric L and I are all saying that there is no energy at the fundamental produced simply by the addition of sine waves that are multiples of the fundamental. What we hear is the result of a non-linear system, either in our ears or in the audio equipment or both.

That being said, my piano produces A0 24dB down from the peak partial, as can be seen on my posted image, so there is still audible, if weak, energy at the fundamental. I can sense it, but don't think a sub is necessary to reproduce it on a DP.


I don't think the illusion is about a non-linearity of the ear. An inner hair cell of our ear has no reason to vibrate at 1f if we have 2f, 3f... frequencies. I think it is about the way our neurons are connected. It is expected that when we ear a 3f 4f 5f frequencies, the "1f" neuron is connected to the 3f 4f 5f neurons and the addition of all the signals stress the first neuron. I think it is expected that related frequencies neurons are connected in order to sum-up what we ear.


My reading over the past 5 years on the acoustic processes of the ear shows that there are a number of theories regarding how we perceive pitch. The most prominant one is the one that applies here. It states that pitches (that is Cs, Ds, and so on, not frequency) are binned together in the the cochlea. Thus the same group of stereocilia perceive all Cs - C1, C2, C3 and so on. We use other cues to differentiate if the pitch seems higher or lower. This is a theory mind you, but, based on it, it seems resonable that non-linearities in the cochlea give rise to the missing fundamental.

A simple test of this is to produce a 500Hz sine wave in your left ear and a 400Hz sine wave in your right ear using audacity and headphones. You will clearly hear a 500Hz sound in the left ear and a 400Hz sound in your right ear, and nothing else, since the pitches are binned separately. Now mix and render the two tracks to a new combined track and listen again. You will now clearly hear both pitches in both ears PLUS a new third pitch at 300Hz. You will not hear any other pitches. We should hear 100Hz but we don't. However, if the pitches are binned, then 300Hz is simply binned along with 100, 200, 300, 400, and 500 Hz. Perhaps it is its proximity to the other pitches that makes it audible.

Re: How much low frequency power does a piano have? [Re: PianoMan51] #2647683
05/27/17 05:24 PM
05/27/17 05:24 PM
Joined: Oct 2013
Posts: 1,694
France
Frédéric L Online content
1000 Post Club Member
Frédéric L  Online Content
1000 Post Club Member

Joined: Oct 2013
Posts: 1,694
France
A stereocillia is just a plain mechanical oscillator. It should act as narrow bandpass filter. I don't think it can vibrate at different frequencies. However, a C3 stereocillia will be vibrate when you play a C2 note since this one has a C3 partial. Is this what you are talking about ?

I have read that stereocillia are ordered by frequencies, never read something about group of related stereocillia. Have you got some pointers.


Yamaha CLP150, Bechstein Digital Grand, Garritan CFX, Ivory II pianos, Galaxy pianos, EWQL Pianos, Native-Instrument The Definitive Piano Collection, Soniccouture Hammersmith, Truekeys, Pianoteq
Re: How much low frequency power does a piano have? [Re: Frédéric L] #2647710
05/27/17 07:12 PM
05/27/17 07:12 PM
Joined: Nov 2013
Posts: 4,090
Southwestern Ontario
P
prout Offline
4000 Post Club Member
prout  Offline
4000 Post Club Member
P

Joined: Nov 2013
Posts: 4,090
Southwestern Ontario
Originally Posted by Frédéric L
A stereocillia is just a plain mechanical oscillator. It should act as narrow bandpass filter. I don't think it can vibrate at different frequencies. However, a C3 stereocillia will be vibrate when you play a C2 note since this one has a C3 partial. Is this what you are talking about ?

I have read that stereocillia are ordered by frequencies, never read something about group of related stereocillia. Have you got some pointers.



Here is one that will start you off in your research.

The traditional theory is called 'Place code theory' formulated by Helmholtz. It posits that the frequency is mapped in the cochlea by position. The Temporal Code theory is more modern and refutes the Place code theory. It posits that frequency is not mapped to cochlear position but to neuronal firing rates. This allows for mode locking and non-linear effects at the level of the neuron.

Re: How much low frequency power does a piano have? [Re: PianoMan51] #2647736
05/27/17 09:21 PM
05/27/17 09:21 PM
Joined: Oct 2013
Posts: 1,694
France
Frédéric L Online content
1000 Post Club Member
Frédéric L  Online Content
1000 Post Club Member

Joined: Oct 2013
Posts: 1,694
France
I havn't read that stereocillias are binned together : we have here a distribution with ordered frequencies. We have a plot with 3 neurons : but the text doesn't tell the relationship between these frequencies.

Perhaps we should understand by binned : some neuron associated to different frequencies are connected to a focal neuron which detect a given pitch.


Yamaha CLP150, Bechstein Digital Grand, Garritan CFX, Ivory II pianos, Galaxy pianos, EWQL Pianos, Native-Instrument The Definitive Piano Collection, Soniccouture Hammersmith, Truekeys, Pianoteq
Re: How much low frequency power does a piano have? [Re: Frédéric L] #2647800
05/28/17 08:55 AM
05/28/17 08:55 AM
Joined: Nov 2013
Posts: 4,090
Southwestern Ontario
P
prout Offline
4000 Post Club Member
prout  Offline
4000 Post Club Member
P

Joined: Nov 2013
Posts: 4,090
Southwestern Ontario
Here is an article on the psychophysical study of pitch perception. It describes in detail the various models, including the spectral and temporal theories and an in depth discussion of the 'missing fundamental' phenomenon, including non-linear processing in the auditory complex. Scan down to 'A Historical Perspective' to read about it.

It is interesting that all the theories can explain portions of pitch perception, but none capture our complete ability to discrimate pitch, especially when the detectable pitch change is less than the neural tuning rate. Example given - at 250Hz we easily hear a 1Hz change in pitch, but the tuning of neural fibres is not narrow enough to account for the small difference. All this implies that we cannot think of the stereocilia as simple mechanical vibrators that respond to a given frequency which is the frequency we perceive. If that were the case, there would have to be an essentially unlimited number of fibres in the cochlea, which defies the basic laws of physics regarding volume.

Re: How much low frequency power does a piano have? [Re: PianoMan51] #2647803
05/28/17 09:23 AM
05/28/17 09:23 AM
Joined: Oct 2013
Posts: 1,694
France
Frédéric L Online content
1000 Post Club Member
Frédéric L  Online Content
1000 Post Club Member

Joined: Oct 2013
Posts: 1,694
France
The previous article shows that the band pass filter is not so narrow. Then with a given frequency, multiple stereocillias will vibrate. I suppose that the brain would have to compute a "maximum" in order to ear the right pitch. A "simple mechanical vibrator" has a given bandpass, then we mustn't have an infinity of them to hear all frequencies.

This would explain some masking used in MP3 compression : if a given frequency makes vibrate neighbors stereocillias, a sound at a near frequency won't produce much effect (the corresponding stereocillias already vibrate).


Yamaha CLP150, Bechstein Digital Grand, Garritan CFX, Ivory II pianos, Galaxy pianos, EWQL Pianos, Native-Instrument The Definitive Piano Collection, Soniccouture Hammersmith, Truekeys, Pianoteq
Re: How much low frequency power does a piano have? [Re: PianoMan51] #2647822
05/28/17 10:35 AM
05/28/17 10:35 AM
Joined: Nov 2010
Posts: 5,554
Melbourne, Australia
A
ando Offline
5000 Post Club Member
ando  Offline
5000 Post Club Member
A

Joined: Nov 2010
Posts: 5,554
Melbourne, Australia
You know when you are following a thread up to a certain point and you suddenly hit a point where you are hopelessly out of your depth?

I have officially reached that point...

Re: How much low frequency power does a piano have? [Re: Frédéric L] #2647831
05/28/17 11:30 AM
05/28/17 11:30 AM
Joined: Nov 2013
Posts: 4,090
Southwestern Ontario
P
prout Offline
4000 Post Club Member
prout  Offline
4000 Post Club Member
P

Joined: Nov 2013
Posts: 4,090
Southwestern Ontario
Originally Posted by Frédéric L
The previous article shows that the band pass filter is not so narrow. Then with a given frequency, multiple stereocillias will vibrate. I suppose that the brain would have to compute a "maximum" in order to ear the right pitch. A "simple mechanical vibrator" has a given bandpass, then we mustn't have an infinity of them to hear all frequencies.

This would explain some masking used in MP3 compression : if a given frequency makes vibrate neighbors stereocillias, a sound at a near frequency won't produce much effect (the corresponding stereocillias already vibrate).

I think you are probably correct. It is fascinating how complex and still mysterious is the ability to perceive pitch, especially the ability to discriminate between two very close pitches, when not played together.

There must be a 'learned' component to pitch perception given the complex harmonic and inharmonic structure of most pitches. By that I mean that we learn to hear the oboe, the flute, the violin, as individual instruments even when playing in unison. A person who has never heard any of those instruments would likely hear a single source sound.

Re: How much low frequency power does a piano have? [Re: PianoMan51] #2647853
05/28/17 01:17 PM
05/28/17 01:17 PM
Joined: Aug 2016
Posts: 397
UK
B
Bambers Offline
Full Member
Bambers  Offline
Full Member
B

Joined: Aug 2016
Posts: 397
UK
Is it fair to call the missing fundamental an illusion?

If it were an illusion the note without the fundamental would sound the same as the one with. With the fundamental present the sound is generally 'fuller'.

Seems quite easy to pick out the point at which the fundamental goes lower than the soundboard resonant frequency when playing note by note down the piano.

Assigning a pitch to the sound seems more a case of identifying the repetition rate rather than specifically picking out the lowest sine wave.

Re: How much low frequency power does a piano have? [Re: Bambers] #2647859
05/28/17 01:38 PM
05/28/17 01:38 PM
Joined: Nov 2013
Posts: 4,090
Southwestern Ontario
P
prout Offline
4000 Post Club Member
prout  Offline
4000 Post Club Member
P

Joined: Nov 2013
Posts: 4,090
Southwestern Ontario
Originally Posted by Bambers
Is it fair to call the missing fundamental an illusion?

If it were an illusion the note without the fundamental would sound the same as the one with. With the fundamental present the sound is generally 'fuller'.

Seems quite easy to pick out the point at which the fundamental goes lower than the soundboard resonant frequency when playing note by note down the piano.

Assigning a pitch to the sound seems more a case of identifying the repetition rate rather than specifically picking out the lowest sine wave.


It could be an illusion in that the missing fundamental can really be missing and we still hear it, because our brain wants us to hear it, possibly for some evolutionary survival reason.

But, I argue that the mechanical structure of the ear (in all its complexity of drum, bones, cochlea) is inherently non-linear, which means that it distorts the sound causing actual additive and subtractive interactions between the partials, which means the fundamental is actually created by the mechanical structure of the ear.

Try my experiment on your DP - play C5 and E5 simultaneously. You will hear G4. The ratio C5:E5 is 4:5, yet we hear G4, which is in the ratio G4:C5:E5 = 3:4:5.

Non-Linear mixing (addition and subtraction of two or more frequencies) is actually used all the time in radio electronics and audio.

In radio, it is used to convert a high frequency radio signal to a constant low frequency signal for efficient amplification. It is also used for frequency multiplication. A sine wave is fed to a non-linear amplifier which produces multiple harmonics above and below the sine wave. The desired harmonic is put through a band-pass filter and amplified.

I mentioned guitar amps and speakers are designed for non-linear operation. There is an emphasis on the second harmonic, which interacts with the fundamental pitch creating the octave below. The result is a rich, warm sounding guitar.

Last edited by prout; 05/28/17 01:46 PM.
Re: How much low frequency power does a piano have? [Re: PianoMan51] #2647867
05/28/17 01:50 PM
05/28/17 01:50 PM
Joined: Oct 2013
Posts: 1,694
France
Frédéric L Online content
1000 Post Club Member
Frédéric L  Online Content
1000 Post Club Member

Joined: Oct 2013
Posts: 1,694
France
It is not the complexity which cause non-linearity, but some kind of saturation, or important displacements. The sound is about very small displacements. This makes me think the ear should be generally quite linear, but I have no proof about it.

The stereocillias could vibrate with high displacement (compared to their size). But This wouldn't change their bandpass, only how they vibrate if they vibrate. They would vibrate with harmonic distortion, but this won't change the fact that they vibrate which is what it is measured. Then no impact.

Last edited by Frédéric L; 05/28/17 02:01 PM.

Yamaha CLP150, Bechstein Digital Grand, Garritan CFX, Ivory II pianos, Galaxy pianos, EWQL Pianos, Native-Instrument The Definitive Piano Collection, Soniccouture Hammersmith, Truekeys, Pianoteq
Re: How much low frequency power does a piano have? [Re: Frédéric L] #2647891
05/28/17 03:23 PM
05/28/17 03:23 PM
Joined: Nov 2013
Posts: 4,090
Southwestern Ontario
P
prout Offline
4000 Post Club Member
prout  Offline
4000 Post Club Member
P

Joined: Nov 2013
Posts: 4,090
Southwestern Ontario
Originally Posted by Frédéric L
It is not the complexity which cause non-linearity, but some kind of saturation, or important displacements. The sound is about very small displacements. This makes me think the ear should be generally quite linear, but I have no proof about it.

The stereocillias could vibrate with high displacement (compared to their size). But This wouldn't change their bandpass, only how they vibrate if they vibrate. They would vibrate with harmonic distortion, but this won't change the fact that they vibrate which is what it is measured. Then no impact.


Here is a paper abstract on the non-linear functioning of the vertebrate auditory system.

"Abstract
The vertebrate ear is highly nonlinear. This is rather surprising since its vibrational amplitudes are so minute in response to normal sound pressures. Generally, one might expect a stable mechanical system to respond linearly when disturbed slightly from its resting state. Thus the nonlinear properties of the peripheral auditory system are of considerable interest inasmuch as they can provide valuable insight into the underlying transduction process in the ear. The two most prominent nonlinear properties are inter-modulation distortion and two-tone suppression. Their characteristics have been studied extensively in the mammalian auditory system by a number of investigators. To provide a comparative view, a series of electrophysiological experiments were conducted in order to determine the nonlinear behavior of the anuran’s peripheral auditory system. The results have interesting implications regarding the origin of nonlinearities, as well as the mechanical basis for frequency analysis, in the vertebrate inner ear in general. Before presenting these findings, several relevant studies of nonlinearities in the mammalian auditory system are summarized, followed by a brief review of the anatomy of the anuran’s ear."

The paper references significant research into non-linearity of the auditory system by Moe, Plomp, and especially Zwicker.

Clearly intermodulation distortion in the physical process is the cause of our ability to sense the 'missing fundamental'. The research on this subject is huge.

edit: another source: non-linearity






Last edited by prout; 05/28/17 03:34 PM.
Re: How much low frequency power does a piano have? [Re: PianoMan51] #2647894
05/28/17 03:32 PM
05/28/17 03:32 PM
Joined: Oct 2013
Posts: 1,694
France
Frédéric L Online content
1000 Post Club Member
Frédéric L  Online Content
1000 Post Club Member

Joined: Oct 2013
Posts: 1,694
France
Quote
This is rather surprising since its vibrational amplitudes are so minute in response to normal sound pressures.


This seems to be compatible with I have said. Thanks for the sharing. Unfortunately, the article is a little expensive if one just want to satisfy its curiosity. I won't know why I was wrong.

Last edited by Frédéric L; 05/28/17 03:34 PM.

Yamaha CLP150, Bechstein Digital Grand, Garritan CFX, Ivory II pianos, Galaxy pianos, EWQL Pianos, Native-Instrument The Definitive Piano Collection, Soniccouture Hammersmith, Truekeys, Pianoteq
Re: How much low frequency power does a piano have? [Re: Frédéric L] #2647898
05/28/17 03:46 PM
05/28/17 03:46 PM
Joined: Nov 2013
Posts: 4,090
Southwestern Ontario
P
prout Offline
4000 Post Club Member
prout  Offline
4000 Post Club Member
P

Joined: Nov 2013
Posts: 4,090
Southwestern Ontario
Originally Posted by Frédéric L
Quote
This is rather surprising since its vibrational amplitudes are so minute in response to normal sound pressures.


This seems to be compatible with I have said. Thanks for the sharing. Unfortunately, the article is a little expensive if one just want to satisfy its curiosity. I won't know why I was wrong.


It seems odd that such minute displacements give rise to non-linearities. However, we have looked at only pitch. The real non-linearity is in our perception of loudness.

The researchers all seem to argue that the non-linearities are the result of some evolutionary advantage.

One interesting point is that the original idea, that pitch perception occurs by some form of rudimentary mechanical/neural time-variant Fourier analysis in the cochlea, has been discarded, since our ability to sense precise pitch occurs in a time interval that is less than the Gabor Interval required for such precision.

The ear is a truly amazing organ.

Re: How much low frequency power does a piano have? [Re: Frédéric L] #2647901
05/28/17 03:49 PM
05/28/17 03:49 PM
Joined: Jul 2012
Posts: 7,187
Northern England.
peterws Offline
7000 Post Club Member
peterws  Offline
7000 Post Club Member

Joined: Jul 2012
Posts: 7,187
Northern England.
I got so bored tonight I actually read through this stuff . . . . .Yamaha's brought out a new range of pianos nobody's interested in . . .guess I'll have to just . . . practice. Sad isn't it? frown


"I am not a man. I am a free number"

"[Linked Image]"
Re: How much low frequency power does a piano have? [Re: PianoMan51] #2647903
05/28/17 03:54 PM
05/28/17 03:54 PM
Joined: Nov 2013
Posts: 4,090
Southwestern Ontario
P
prout Offline
4000 Post Club Member
prout  Offline
4000 Post Club Member
P

Joined: Nov 2013
Posts: 4,090
Southwestern Ontario
It is fascinating how threads often meander far from the desired trajectory. However, we often learn stuff on the way.

Re: How much low frequency power does a piano have? [Re: PianoMan51] #2648080
05/29/17 06:23 AM
05/29/17 06:23 AM
Joined: Sep 2009
Posts: 6,838
Raleigh, North Carolina
MacMacMac Offline
6000 Post Club Member
MacMacMac  Offline
6000 Post Club Member

Joined: Sep 2009
Posts: 6,838
Raleigh, North Carolina
Yes, prout. Lots of interesting stuff here sometimes, despite the divergence from an OP's topic.

There's one thing I'd like to add ...

The posts here (and the cited paper) speak about the physical causes of sound, But there little here about the psychological portion. The relationship between the two is at the same time the most interesting and the most difficult.

My point is this: Perception is entirely in the mind. And that's where we live. We don't live in a reality world. We live in a perceptual world.

Reality has air vibrated by physical objects. But reality has no sound. Only the mind has sound.

Reality has electromagnetic waves, and the eyes respond to some of those. But reality has no light, and no color. Only the mind has light and color.

Everything we think we know is really just perception. We build a cognitive model of reality beginning in childhood, and we tend to think that perception is reality. It is not.

Appropriate inquiry can deduce real, meaningful relationships between reality and perception. Often those relationships are simple and sensible ... which leads us to believe even more that there is a direct relationship between the two. But often those relationships are complex, bizarre, and even nonsensical. In the end these inquiries reveal that reality is not at all what we think it is.

The cited paper on the subject of the "missing fundamental" is just one example of that. Optical illusions offer more examples. But if you study modern physics you'll find examples much more profound. Ones that make optical illusions and missing fundamentals seem like minor anomalies.

Re: How much low frequency power does a piano have? [Re: MacMacMac] #2648089
05/29/17 07:34 AM
05/29/17 07:34 AM
Joined: Nov 2013
Posts: 4,090
Southwestern Ontario
P
prout Offline
4000 Post Club Member
prout  Offline
4000 Post Club Member
P

Joined: Nov 2013
Posts: 4,090
Southwestern Ontario
Well said.

I have spent my life immersed in physics, electronic design, astronomy and music. I love how theories give us a schematic means of comprehending and predicting behaviour in the universe without actually 'seeing' the underlying reality.

We need words like 'sound', 'colour', and such as descriptors of our mapping of the external world to our mind. Sound waves propagating through clouds of galactic hydrogen is one way to create stars. We would not hear the sound, yet it is the simplest way of thinking about the mechanism.

My vacuum tube designs allow me to think of electrons flowing from cathode to anode. My MOSFET designs allow me to think of holes flowing from source to drain. Yet, the 'reality' is that there are no physical electrons, or holes, just wave functions that collapse when I try to measure them, and all that activity is just a 'disturbance in the force', or so the latest theories would have me believe.




Last edited by prout; 05/29/17 07:43 AM.
Re: How much low frequency power does a piano have? [Re: PianoMan51] #2649191
06/01/17 11:01 AM
06/01/17 11:01 AM
Joined: Aug 2016
Posts: 80
S
similar Offline
Full Member
similar  Offline
Full Member
S

Joined: Aug 2016
Posts: 80
I think the discussion about the use of subwoofers for digital pianos is missing something.

To me, the biggest reason to use a subwoofer is to ensure the quality of the frequencies you get. By only high passing the signal to the main speakers near the sub's low pass frequency, you ensure less work (and even better, less lower frequency work) for the main speakers. This will generally improve the sound of the higher frequencies (whatever was passed to the lowest amp and driver for the main speaker). Also, the low frequencies can often be more faithfully reconstructed by a quality subwoofer than by a quality main speaker.

But subwoofers seem to be generally more expensive when "quality" and spl matching, like getting a brand's matching sub to their pair of studio monitors, so you might interpret the above as requiring higher quality (more expensive) subwoofers than main speakers.

Sorry, following a tangent from the OP.


Beethoven, Bach -> Kawai CA-97 -> Garritan CFX Full -> Neumann Klein and Hummel 310s
Re: How much low frequency power does a piano have? [Re: PianoMan51] #2649193
06/01/17 11:08 AM
06/01/17 11:08 AM
Joined: Nov 2013
Posts: 4,090
Southwestern Ontario
P
prout Offline
4000 Post Club Member
prout  Offline
4000 Post Club Member
P

Joined: Nov 2013
Posts: 4,090
Southwestern Ontario
Yes, off-loading the main amps is a good thing. However, it can be devilishly difficult to get a smooth crossover, both in amplitude and phase, and this tends to occur right around the place where you want the best low end response for a piano.

Re: How much low frequency power does a piano have? [Re: prout] #2649205
06/01/17 11:34 AM
06/01/17 11:34 AM
Joined: Jan 2016
Posts: 904
Milano
N
newer player Offline
500 Post Club Member
newer player  Offline
500 Post Club Member
N

Joined: Jan 2016
Posts: 904
Milano
Originally Posted by prout
Yes, off-loading the main amps is a good thing. However, it can be devilishly difficult to get a smooth crossover, both in amplitude and phase, and this tends to occur right around the place where you want the best low end response for a piano.


Agreed.

My audiophile colleague carefully limits the bandwidth to each of his horns-drivers. But he has a massive amount of equipment, measuring gear, time, and expertise.

For regular people like us, the engineer who built my speakers just told me to try integrating the subs both ways to see what sounded best in my room.

Running full bandwidth to both the monitors and subs sounds much better than any crossover scheme I tried. Some of that was luck; room measurements showed the monitors dropped off steeply around ~70hz, just where the sub picked up. . .

Re: How much low frequency power does a piano have? [Re: PianoMan51] #2649206
06/01/17 11:34 AM
06/01/17 11:34 AM
Joined: Aug 2016
Posts: 80
S
similar Offline
Full Member
similar  Offline
Full Member
S

Joined: Aug 2016
Posts: 80
Right, the crossovers at around 80Hz are pretty close to the bottom end of the piano's bulk power.

Perhaps better for piano is going with a tri-amped main speaker. This is what I have currently rigged up. No sub, but for each main speaker a low driver and amp good from about 35 Hz and taking up to 650Hz, a mid driver/amp from that to 2kHz, and a high up to ~15kHz to a slow rolloff. Sounds a lot better especially for separation of all voices across the keyboard than the same brand's bi-amped lower-tier model I briefly used. But it could definitely just be due to other overall quality improvements.


Beethoven, Bach -> Kawai CA-97 -> Garritan CFX Full -> Neumann Klein and Hummel 310s
Re: How much low frequency power does a piano have? [Re: newer player] #2649211
06/01/17 11:40 AM
06/01/17 11:40 AM
Joined: Aug 2016
Posts: 80
S
similar Offline
Full Member
similar  Offline
Full Member
S

Joined: Aug 2016
Posts: 80
Originally Posted by newer player
Running full bandwidth to both the monitors and subs sounds much better than any crossover scheme I tried. Some of that was luck; room measurements showed the monitors dropped off steeply around ~70hz, just where the sub picked up. . .

Are you saying that without external crossovers (bass management) the monitors happened to naturally drop off in your room around 70Hz? Nice thumb


Beethoven, Bach -> Kawai CA-97 -> Garritan CFX Full -> Neumann Klein and Hummel 310s
Re: How much low frequency power does a piano have? [Re: similar] #2649221
06/01/17 12:09 PM
06/01/17 12:09 PM
Joined: Jan 2016
Posts: 904
Milano
N
newer player Offline
500 Post Club Member
newer player  Offline
500 Post Club Member
N

Joined: Jan 2016
Posts: 904
Milano
Originally Posted by similar
Are you saying that without external crossovers (bass management) the monitors happened to naturally drop off in your room around 70Hz? Nice thumb


Yes. I suppose you could say there is a "natural" crossover but that is pure luck.

Of course extensive measurements, careful sub placement, and an ideal room helped. Fact that smaller monitors "don't" reproduce sub frequencies and that good subs "only" reproduce sub frequencies also helped.

Getting round discs inside a few rectangular boxes to replicate long strings inside one big funny looking piano box requires a lot of vodoo science. . .

Re: How much low frequency power does a piano have? [Re: prout] #2751022
07/12/18 02:55 PM
07/12/18 02:55 PM
Joined: Jun 2012
Posts: 21
Princeton, Texas
D
Duke LeJeune Offline
Full Member
Duke LeJeune  Offline
Full Member
D

Joined: Jun 2012
Posts: 21
Princeton, Texas
Originally Posted by prout
There is little energy even on a 9' grand below about 60Hz and little energy below 100Hz on small pianos.


Thank you for your excellent in-depth analysis, spread out over several very informative and thorough posts, which points to this conclusion.

A little over a year ago I was trying to figure out "where the goal posts are" so I could build a gig-worthy speaker for my son, who plays DP. I came to the conclusion that the fundamental and first overtone were too low in energy to be audibly significant for A0 and A#0, and that the lowest frequency where there was arguably significant energy was at the first overtone of B0, around 62 Hz.

But I would trust your analysis over mine!

Just so happens that imo 62 Hz is also where the goal posts are for a good bass guitar cab, that being the first overtone of B0. While the bass guitar itself does produce significant energy at the lowest fundamentals, reproducing those lowest fundamentals is not necessary for pitch perception, and may even be undesirable (steps on the kickdrum, interference with FOH speakers, turns into a wall of mud on stage and out in most venues, and imposes a significant size/weight/cost penalty).


Owner & designer, AudioKinesis
Page 2 of 2 1 2

Moderated by  Piano World 

(ad)
Sweetwater - Keyboards
Sweetwater
New Topics - Multiple Forums
Feeling disconnected while playing my recital
by Muove. 11/22/18 05:25 AM
What Acoustic Piano Should I Buy
by Reny27. 11/21/18 06:44 PM
U1 vs N1
by Porcelain. 11/21/18 05:27 PM
Is a Piano Hammer Hardness list possible?
by Chernobieff Piano. 11/21/18 04:38 PM
(ad)
Pianoteq
PianoTeq Petrof
Forum Statistics
Forums40
Topics188,458
Posts2,763,346
Members91,546
Most Online15,252
Mar 21st, 2010
(ad)
Accu-Tuner
Sanderson Accu-Tuner
Please Support Our Advertisers
Dampp Chaser Piano Life Saver

Sweetwater

PianoTeq Petrof
Piano Buyer Spring 2018
Visit our online store for gifts for music lovers


 
Help keep the forums up and running with a donation, any amount is appreciated!
Or by becoming a Subscribing member! Thank-you.
Donate   Subscribe
 
Our Piano Related Classified Ads
| Dealers | Tuners | Lessons | Movers | Restorations | Pianos For Sale | Sell Your Piano |

Advertise on Piano World
| Subscribe | Piano World | PianoSupplies.com | Advertise on Piano World |
| |Contact | Privacy | Legal | About Us | Site Map | Free Newsletter |


copyright 1997 - 2018 Piano World ® all rights reserved
No part of this site may be reproduced without prior written permission
Powered by UBB.threads™ PHP Forum Software 7.6.2