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AR speaker low frequency perspective


Aadams

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"I hope the visual speaks for itself."

First of all, the first key of all standard pianos -- those used perhaps 99.99% of the time for any recording -- is A0 at 27.5 Hz., not 16 Hz.  Only the obscure and very expensive Stuart & Sons special piano (shown in your visual) and the rarely used, supremely expensive Austrian Bösendorfer Model 290 Imperial (half a million US dollars) have the extra bass and treble keys that allow a 16 Hz note, similar to an organ 32' foot pipe.  But those bottom keys are not well heard due to the difficulty in reproducing nether-bass frequencies with strung vibrating mechanism; i.e., those notes can barely be felt or heard anyway in a live performance.  Only a close-miked recording of the piano's sound will show any palpable low-frequency energy; moreover, nearly all recordings are made with microphones well above the soundboard or strings to keep the sound natural. 

In addition, all of these pianos have to be at least the Concert Grand versions, 9+ feet in length or larger, and nearly all orchestral (and most jazz) piano recordings are made with the Steinway Model D Concert Grand.  Rarely are recordings made with anything else except a few special recordings.  Then there is the issue of virtually no music ever having been written by composers for the notes below the standard-piano frequencies.  Even A0 is rarely in use on any piano.  

Consider the the issue of the "-3dB down point" of these various loudspeakers.  The -3dB down point is strictly a technical measurement to give one the point in which anechoic frequency response dips below the reference-output level.  This is an free-field type of measurement, not a room measurement.  With room gain, it's likely that 30 Hz in any AR-3a is not going to be diminished by very much, barely noticeable with most recordings.  Almost every room has "room gain," a phenomenon that actually bumps-up the low frequencies significantly, so that there is quite a lot of bass reinforcement below the loudspeaker's normal bass resonance. While it's certainly true that the AR9 will sound more full reproducing the bottom octaves than an AR-3a, or an AR-3a more so than an AR-5, there is really very little lost when playing most music, particularly piano music, with any of these speakers.

If the extreme low bass is the number-one issue, an equalizer can always be used.  This is usually an organ or electronic-music issue, not a piano issue.  AR woofers have low harmonic distortion, so these speakers can be equalized to bump up the subterranean bass frequencies if needed. 

--Tom Tyson

 

Edited by tysontom
To improve the tone and clarity of the original message!
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Tom Tyson

Once again you are correct, and we agree including the discussion on the sound of the piano.   I should have provided a little more explanation for the keyboard image above.

This graphic is not about how low a speaker must go to produce the lowest tones in music.  On the contrary the graphic is about the blue line that is drawn below the statement regarding the lowest notes in most music and the other end of that line which is pointing to the E1 key at 42 hz.  

The message here is, in fact, almost all recorded music occurs above 42hz and can be enjoyed fully without the need for a speaker that can respond much below that point. 

It explains why the AR3a is still revered and why the OLA was such a huge success, i.e they are both going strong as they cross the blue line and that is about all any listener really needs for bass.

IMO there is much imagining about the amount of actual low bass that exists in most music.

The 108 keyboard is merely a device that puts it all into perspective.  And that is all.  

Sincerely

Aadams

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Aadams, it probably goes without saying that I will frequently jump at the chance to debate this subject -- I'm sure you know that by now -- but you are exactly right that I should have first asked where you were going with this post.  As you left it, however, it was wide open to interpretation, and I was right in there.  It might have been better for you to have described what you were trying to say in your first message; thus a debate could have been averted.  I completely missed the 42 Hz blue line thing you mention above.  I see the blue line, but I didn't see the reference to the 42 Hz in your image; I now understand that you were pointing to a specific piano key that represents 42 Hz, the approximate resonance frequency of the larger AR bookshelf speakers. 

I tend to get into a spirited discussion anytime I suspect something isn't correct, but I also realize that you are an AR buff, no argument there.  Discussion and debate are good things and no harm meant, but I tend to raise the tension level sometimes, so I apologize for that.

--Tom Tyson 

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On 12/1/2018 at 11:50 PM, tysontom said:

I tend to get into a spirited discussion anytime I suspect something isn't correct, but I also realize that you are an AR buff, no argument there.  Discussion and debate are good things and no harm meant, but I tend to raise the tension level sometimes, so I apologize for that.

--Tom Tyson

If I was going get nailed it is better coming from someone who can spew good factual venom coherently.  So thanks for that.    I found a picture that captures my thoughts as I was composing my response.

image.thumb.png.636ba54b5b004375f073c2ddd1353254.png 

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On 12/1/2018 at 8:56 PM, tysontom said:

"I hope the visual speaks for itself."

First of all, the first key of all standard pianos -- those used perhaps 99.99% of the time for any recording -- is A0 at 27.5 Hz., not 16 Hz.  Only the obscure and very expensive Stuart & Sons special piano (shown in your visual) and the rarely used, supremely expensive Austrian Bösendorfer Model 290 Imperial (half a million US dollars) have the extra bass and treble keys that allow a 16 Hz note, similar to an organ 32' foot pipe.  But those bottom keys are not well heard due to the difficulty in reproducing nether-bass frequencies with strung vibrating mechanism; i.e., those notes can barely be felt or heard anyway in a live performance.  Only a close-miked recording of the piano's sound will show any palpable low-frequency energy; moreover, nearly all recordings are made with microphones well above the soundboard or strings to keep the sound natural. 

In addition, all of these pianos have to be at least the Concert Grand versions, 9+ feet in length or larger, and nearly all orchestral (and most jazz) piano recordings are made with the Steinway Model D Concert Grand.  Rarely are recordings made with anything else except a few special recordings.  Then there is the issue of virtually no music ever having been written by composers for the notes below the standard-piano frequencies.  Even A0 is rarely in use on any piano.  

Consider the the issue of the "-3dB down point" of these various loudspeakers.  The -3dB down point is strictly a technical measurement to give one the point in which anechoic frequency response dips below the reference-output level.  This is an free-field type of measurement, not a room measurement.  With room gain, it's likely that 30 Hz in any AR-3a is not going to be diminished by very much, barely noticeable with most recordings.  Almost every room has "room gain," a phenomenon that actually bumps-up the low frequencies significantly, so that there is quite a lot of bass reinforcement below the loudspeaker's normal bass resonance. While it's certainly true that the AR9 will sound more full reproducing the bottom octaves than an AR-3a, or an AR-3a more so than an AR-5, there is really very little lost when playing most music, particularly piano music, with any of these speakers.

If the extreme low bass is the number-one issue, an equalizer can always be used.  This is usually an organ or electronic-music issue, not a piano issue.  AR woofers have low harmonic distortion, so these speakers can be equalized to bump up the subterranean bass frequencies if needed. 

--Tom Tyson

 

Note that I have toned-down my original message!  I got a little carried away!

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I found an on-line version of an article by D.B.Keele, jr,  who specialized in testing and reviewing (sub)woofers.

 http://www.gammaelectronics.xyz/audio_11-1992_sub.html

I thought it would be interesting to include some of his findings in the discussion of bass reproduction.

Figure 1 is the frequency response of 4 subwoofers.

Figure 2 is maximum peak sound output vs frequency including the effects of room gain.

 Therefore the typical manufacturers’ spec on frequency response (measured at 1 w or 2.83 volts) does not predict completely  how the speaker will perform at realistic sound level in your room.

 

794746848_fig1.thumb.PNG.9ab475c12bb25afa6a57d138d91dd7c9.PNG1339313076_fig2.thumb.PNG.823374b4e5bc16763bfdd4944b28fe49.PNG

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This is a clip of a solo by Victor Wooten playing a 5 string bass. The solo gets into the 70hz range but mostly stays well below in the 50s and 40hz range.  The lowest note played is a D1 at 36hz.  Musical bass this low is a rare thing in western music.

Written music for traditional musical instruments, other than a pipe organ,  almost never calls for any tuned note lower than 41hz. 

Edit: If you are listening on ear buds the lowest notes will not sound, although you may a hear a “splat” sound, and the strong first harmonics in the 70 to 90hz range may be fuzzy.  If you use high quality small speakers, you still will not hear the low notes, but the harmonic series and overtones will sound so strongly that your brain will fill in the low fundamental note as though it is being sounded.    The only way to get a palpable sensation of the last octave of musical bass is to use a speaker that will reproduce the fundamental frequencies at adequate levels.

 

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  • 1 month later...
On 12/5/2018 at 8:32 AM, ligs said:

Figure 2 is maximum peak sound output vs frequency including the effects of room gain.

Ligs  I have looked at these graphs several times over the last weeks and cannot see the room gain component in the graph.  I also read the linked article on sub woofer comparisons.

Regarding room gain 

I am confident that speaker placement in some rooms can add sufficient gain to smaller speakers so the low notes can sound louder, but if you find a spot that can raise the 36hz -10 db point of an AR 10” for instance to - 3db or even - 0db you will most likely create some overemphasis up to and including the first harmonic high bass range.  IMO

Cheers

Adams

 

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