Why not the piano as a reference for bass

@richardbrand , my investigation into the loudness of the fundamentals and first few overtones of the lowest piano notes was based on the spectra of those notes played on a grand piano, as I figured that would be applicable to amplified electric piano.

I presume the electric piano was "attempting to sound like a real piano".  My  customer said that he used the same model electric piano as Elton John.  He mentioned it to me but I don't remember the specific model.  I think it was a Yamaha. 

@audiokinesis 

Thanks for the clarification!

I don’t agree that the low notes on a modern grand piano (piano-forte or soft-loud) contain so little energy that they do not merit being reproduced.  Bosendorfer and Stuart keep extending the keyboard downwards!  I don’t think Beethoven would have agreed either - he was very quick to extend the range he wrote for when gifted pianos which went further up and down!

There is of course a fundamental difficulty in judging sound quality against amplified sources - there is no original to compare to.

Anyway, I use soft piano music to judge atmospherics and double bass for bass impact ... but the main thing is to enjoy your music

@richardbrand wrote: "I don’t agree that the low notes on a modern grand piano (piano-forte or soft-loud) contain so little energy that they do not merit being reproduced.  Bosendorfer and Stuart keep extending the keyboard downwards!"

Just to be clear, I’m not saying that the lowest notes on a normal grand piano contain so little energy that they do not merit being reproduced. 

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 don’t know whether this is a grand piano or not, but it shows the spectra of the lowest notes starting with A0.  Pause it after each note and look at how much energy is in the fundamental and first overtone:

piano sound spectrum - YouTube

Anyone else interested in why piano might or might not be a good instrument for evaluating a speaker’s bass response is invited to do the same.   There’s just not a whole lot of true low bass energy. 

@audiokinesis

piano sound spectrum - YouTube

From the comments, the guy who posted that video had no idea what microphone was used, let alone what piano or where the microphone was positioned! 

What I do find interesting is the low modes that are excited when high pitch notes are played.  As I wrote above, the whole piano resonates - after all, it is filled with more than 88 tuned resonators and felt can only damp so much.

Sure the low notes also carry a lot of harmonics, which is why the piano sounds like a piano and not like a pure pipe organ. Agreed, many people may not hear the fundamentals of low notes, and few indeed will directly hear the 16-Hz fundamental of a 108-key Stuart piano's lowest note.  Few subwoofers will even go close with any sort of accuracy. Same goes for the 8-Hz fundamental of Sydney Town Hall's organ with its 64 foot long Gravissima pipe.  You can't hear it but you can certainly feel it!

I have always used well recorded piano compositions as an analytical tool for determining system. I will attempt to explain how I use piano recordings as an analytical tool.  Rather than concertos and symphonies, it is best sonatas.  I have some sonatas that, rather than solo piano, add a violin.   That is in my opinion the best analytical tool.  So how and why? …

Crossover and Driver Integration:  The piano, as others stated, is a singular instrument covering a broad frequency range.   Problems with speaker driver integration and crossover design, or issues with ragged frequency response of electronics become easily evident by using well recorded piano recordings.  As an example, in my past, I had hybrid Apogees.  The lower piano registers were slow and smeared compared to the wonderful midrange and highs.  
 

Dynamics:  While not the best test for percussive crescendos or rock dynamics, the piano by definition as a percussion instrument, is one of the best instruments to use for analyzing system dynamics, especially microdynamics.  While I agree in part with @audiokinesis that the fundamental and first overtones do not have the same impact as other instruments, well recorded closed miked piano will have strikingly vivid first wave percussive impact.  The real value is in analyzing the microdynamics of secondary harmonics and how ppp notes are developed in a composition.  
 

Detail Retrieval:   Well recorded piano is an excellent test for detail retrieval including, harmonic decay, the sound of the hammers vs the strings vs sound board, as well as how the notes decay into the venue.  Piano recordings can easily discern engineering techniques such as close miking vs far miking.  A well designed audiophile system should be able to discern these attributes of well recorded piano.  Here, combined with my discussion on dynamics, is where the piano is excellent for bass analysis.  Analyze bass note first wave (fundamental impact). Is it sharp and striking.  Analyze how it decays and the sound of all the secondary harmonics.  Determine if you can discern the hammer strike from the string sound and sound board.  This is an excellent test for comparing equipment.    
 

Imaging:  Closed miked piano recordings will be able to develop an image that shows the position of the mike relative to the keyboard.  Image palpability will be evident.  
 

In conclusion, piano recordings are an excellent analytical tool in general, and for bass as well.  Yes, you will need to use other records of other instruments to analyze bass impact, but these others are not as good for bass detail and especially for bass integration.  
 

Apologies for my usual pontifications and typos in advance.