Why not the piano as a reference for bass


I see a lot of commentary/reviews on a systems bass response that all seem to hinge on the 41 hz double bass and such range.  At 27.5 the A0 note on a piano seems a better point to judge.  Lots of piano in normal music vs say an organ note.  I know when I feel that deep chord played it is one of things I enjoy about listening the most!  Was listening to Wish you were here live and the piano was sublime.

So is it more of how much musical energy is perceived in the 40 hz range or what that makes this more of a reproduction benchmark?

I welcome your input!

New Joe Bonamassa out BTW!

guscreek

@billpete 

Have you witnessed the 64 foot pipe?

Alas no!  I am slightly friendly with several organists in Sydney but none has hinted when that 64 foot monster might be exercised.

Mostly I hear church and cathedral organs, and the refurbished beast in the Sydney Opera House.  Olivier Latry, the organist from Notre Dame in Paris, featured in Saint-Saens Organ Symphony and Poulenc's Concerto for Organ, Strings and Timpani - one of my personal favourites.  The next day we went to his organ masterclass at the Opera House.  It is amazing how each student had a USB stick with their personal settings for the organ configuration.  I'd like to build a relational database representing that organ and its multiplicity of parts.

I have heard a piano recital given on a Sturt and Sons concert grand piano, but not the full 108-key model.  The Australian Broadcasting Corporation released video and CDs of Beethoven's Piano Concertos played on a Stuart piano.

@audiokinesis 

I’m saying that the lowest fundamentals (and sometimes the corresponding first overtones) of the lowest notes of a non-Bosendorfer grand piano contain so little energy that they do not merit being reproduced in a live music setting

I want to try to nip this idea off, here and now!

Just try this little experiment.  Find yourself a mechanical (not electronic) piano and play the lowest key.  You will hear the fundamental note, plus overtones.  To discover what the first overtone sounds like, move up one octave and play that key.  If the two notes sound as if they are the same frequency, then you cannot hear the lowest fundamental.  But my experience on a Kawai upright piano is exactly the opposite, the lowest note is clearly an octave lower and is clearly audible.  Just in case somebody suggests that the fundamental one octave up is also inaudible, hop another octave up and repeat.  They cannot all be inaudible!

Why an octave? An octave is just double the frequency and in Western music there are eight white piano keys spanning an octave (which is why the Latin for eight features in its name).  There are seven white keys and five black keys before each octave pattern repeats - 12 notes in all.  When Pete Townshend said he chose his double bass for the session, he doubled his pay by doubling this on an electric bass guitar 12 notes higher.  Had me a bit confused but he was just playing one octave up, something very common in orchestral pieces where cellos double the basses, the picolo doubles the flute and so on.

The physics of the fundamental vibration of a string are well known.  The vibration frequency depends on the length of the string, the mass of the string and the tension in it.  The fundamental frequency is where the entire string between its fixed ends moves in the same direction.  But there is another mode, where the middle of the string remains stationary, and the two halves move in opposite directions.  This is the first harmonic, and it is an octave up from the fundamental.

And there are even more vibration modes, where there are four, five, six and so on stationary points in the string.  By and large these modes do not sound pleasing.

One more thing.  A string can also vibrate along its length, and that vibration can be picked up.  Usually the sound is horrible, like a violinist’s finger sliding on the string.  When bowing, it is important that the bow remains at right angles to the string to avoid longitudinal resonances.  It is said that violinists take about five years to learn how to use the left hand to get the right notes.  The next five years is learning how to bow properly.

So can piano be a useful guide to loudspeaker bass reproduction?  Absolutely.  I will take four speakers I am familiar with as examples.  The first is the market-leading bookshelf speaker from KEF – the LS50.  Its bass output has a 3-db roll-off at 79-Hz, which is well over an octave above the 31.5-Hz fundamental of a standard piano’s lowest note.  You won’t get much of its first harmonic either!

Staying with KEF but spending maybe eight times as much, we get the slightly bigger bookshelf KEF Reference 1.  Its 3-db bass rolloff is at 45-Hz so you will not get much of the fundamental but the first harmonic should be all there.

My third speaker is a full-range electrostatic from Quad – the ESL-2905. I cannot find its 3db rolloff but it is flat to 45-Hz and 6db down at 31-Hz.  No real need for a subwoofer here.

Finally to a subwoofer – the 18” servo controlled Velodyne DD-18.  This has a 3db rolloff at 14.1-Hz, more than an octave below that fundamental.  Good for a Bosendorfer or Stuart concert grand.

The Velodyne fleshes out the Reference 1 beautifully, and takes a bit of the bass load off the Quad, which otherwise has little need of a sub.

@richardbrand wrote:  "To discover what the first overtone sounds like, move up one octave and play that key.  If the two notes sound as if they are the same frequency, then you cannot hear the lowest fundamental. But my experience on a Kawai upright piano is exactly the opposite, the lowest note is clearly an octave lower and is clearly audible."

I don’t think this is the proof you think it is, and I hope you don’t mind me posting a somewhat counter-intuitive contrary opinion.

Even if we cannot hear the lowest fundamental, those two notes will NOT sound as if they are the same frequency because the interval between the harmonics is TWICE as wide for the key that is one octave higher.  The ear/brain system PERCEIVES the missing fundamental by inferring it from the  interval (or spacing) between the harmonics.  Please Google "missing fundamental", as this perceptual phenomenon is very much in play at the far left-hand end of the piano keyboard.

A few years ago the local Yamaha piano dealer rented our local concert hall, The Kravits Center, in West Palm Beach, for an entire weekend to promote pianos.  A concert pianist was hired to demonstrate and compare the entire range of instruments from the mighty C9 on down.  The most impressive range to me were the upper end of the Clavinova range.  These are electronic instruments voiced to clone the sound of Yamaha C7 and C9 Concert Grands.  The keyboards are dimensioned and weighted to mimic the full sized instruments as well.  Some very accomplished pianists tried them and verified the claim.  I have perfect pitch and in terms of tonality and dynamics at least in the hall going from one to the other, the sound was indistinguishable.  That was on day one.  By day 3, the C7 was going ever so slightly out of tune which gave it away in favor of the Clavinova.  The C9 held firm.

@billstevenson 

I went to a violin / piano recital at the Sydney City recital hall last week, where in the 20 minute interval, a piano tuner came on stage to work on the concert grand piano in full view of those who did not need a beer or a bubbly!  That’s pressure ...

It would be interesting to learn if Yamaha bothers to synthesize the fundamentals for the lowest notes, or just creates the harmonics.  And to learn about the transducers (speakers) they use to produce the sound.  These extra variables are why I suggested doing your own experiment on a genuine mechanical piano.  It is no use listening to recordings through loudspeakers especially if the speakers are in your laptop.

In my sleep last night, I thought of another reason why the piano is an excellent sound reference.  It is because the sound produced from a single key depends only on how quickly the key is pressed, and the piano itself.  The ’touch’ of the pianist is irrelevant because the hammer mechanism is decoupled from the key mechanism.

That is unless the pianist reaches inside and manipulates the strings ...