Dynamic range: A stab at real world numbers

Some technical analysis with my rig
I have been doing some thinking about what differentiates average quality from high quality sound systems in
general and I keep coming back to dynamic range (no surprise) as the key ingredient. I went through this to see what

kind of theoretical and real dynamic range is possible with my current gear.

What separates a high quality amp or preamp from others?

One thing for sure is its ability to accurately control the signal level, relative to noise level. If the
signal is too tiny it simply is masked by the inherent noise floor. As you raise the "volume" imagine the whole
structure rising from the noise floor. When small signals are masked in the noise floor the actual result is
decreased signal content (IOW, if you took the mathematical difference between what comes out of your cd player
and the actual signal out of the preamp/amp the normalized result is larger when the low level details are
buried). What this means sonically will vary, but it can be likened to dull sounding, or a feeling that there
is grain (a loss of transparency). The ability to have a very low noise floor is necessary far a piece to
manifest good micro dynamics (the quality that allows the sound to bristle with life and vibrancy/sheen). It is
far easier to retain the big peaks (macrodynamics) as they are much higher than the noise floor. We are mostly
paying for the effort to drive the noise floor as low as possible.

Real world numbers

In most high quality preamps this noise floor is very low, usually > 95 dB below max output (same with most
high quality amps). For instance my LS15 claims -98 dB noise floor (@ ~2vrms rated output), while the
VT100MKII, claims a -95 dB noise floor. Since the VT100MKII has 23.5 dB gain, it reaches its 8 ohm rated power
of 100 wpc (28.43 volts) with just about 2 volts driving the amp.

CD players that have 16 bits of resolution have (dB = 6.02n + alpha, where alpha = 4.77 peak and 0 average, and
n= numBits) => 6.02(16) + 4.77 = 101 dB peak and 96 db average dynamic range. Seems like a great match. The two
pieces above have noise floors about equal to the average 16 bit resolution specification. Most cd players have
outputs of about 2 volts rms. My Marantz SA11 has 2.5 Vrms SE, and 5 Vrms balanced. Since I run in balanced
mode and I like my hearing, my preamp does not amplify anything from in to out; rather, it massively attenuates
the signal. (As an aside the LS15 provides 12.5 dB gain in balanced mode. This can be cut in half with a gain
reduction kit from ARC).

Speakers and listening SPLs: The dynaudio contour s3.4 spec states max long term power is 300 watts. With a
sensitivity of 88 dB@ 1Watt-meter, this is a max long term SPL of 119 dB @ 1 meter (at my listening distance of
9 feet and max rated power of the amp of 100 wpc, this drops to 105.2 dB continuous). If the speaker were
played in an anechoic chamber ( noise floor of 0 dB), then it would seem that @ 1 meter the S3.4s have about
119 dB uncompressed dynamic range. Of course, my house has a noise floor of probably 40 dB. Given my amp at 100
wpc and listening distance of 9 feet, then my real-world dynamic range is then 105 - 45 = 60 dB. If all my kids
are out, and the HVAC is off, and its dead nuts quiet, then maybe I have 105 - 30 = 75 dB dynamic range. My
speakers (nominally) have much more headroom than anything else in my current configuration.

How much dynamic range am I actually experiencing?

So, now just how much of the CD players wide dynamic range (assuming a rare cd recording that is not freaking
compressed by the common trend of "loud" recordings, and it actually has close to its theoretical max dynamic
range of 95 dB) is actually being portrayed by my speakers?
I will pick MFSL mastering of Patricia Barber's Modern Cool, captured in SACD. This is one of the most dynamic
recordings I own. "For Company" has bass lines and drum /cymbal transients, not to mention her haunting vocals,
all cast out in bold relief and palpable realness.
If I crank the LS15 to ~0dB (not wide open still, mind you it still adds 6 dB!), thereby passing the entire SA11
signal, I would get whatever is on the recording (I’m guessing it's at least 85 dB), dynamic range wise. Since
the preamp/amp/speakers have a range of well over 90 dB, I get to actually enjoy the full
dynamic range (minus the noise floor). However it's darn loud!! I usually never listen that loud. That same
song played at 10 watt peaks yields 95 dB at the listening position...still pretty loud...now, however due to
the noise floor of my environment, what am I getting (assuming the lowest signals are preserved, which they
probably are not) with the noise floor is now about 95-30 (kids out) about 65 dB of dynamic range, on average,
and this from my BEST recordings.
This seems to be overkill and makes me question my sanity about spending hundreds of dollars on freaking
cabling...yeah and how does that help the dynamic range ;)

What do you think? Are my numbers "sound"????

Enjoy the music
the preamp/amp/speakers have a range of well over 90 dB, I get to actually enjoy the full

Most speakers are limited to roughly 60 db dynamic range...as you play louder the noise floor from distortion etc rises and therefore masks very low level sounds. To a certain extent this does not matter too much as your ears also suffer from masking too\ (even if they can hear 120 db of dynamic range they cannot unmask very soft sounds when ther eis loud music ...although amazingly you can usually hear sounds that are 15 db below the noise floor!!!)

If you understand this issue with speakers then you will realize that CD dynamic range is for all intents and purposes ....more than good enough!
Shadorne: where do you get that info that most speaks are ~60 dB limited? I understand the effects of non-linear dynamic compression of the actual drivers, but unless you test a given speaker in a lab setting with sophisticated test equipment, you can't truly know the distortion of all dynamic driver based speakers. Take the Dynaudio Evidence Masters: they are designed and verified to produce a distortion free (compression free) dynamic range of 126 to 129 dB. Surely not your typical speaker. I don't know for sure if the smaller sibling (the S3.4) is compression free at its rated long term power (119 dB 1 meter), but I would bet the speakers that they are much more than 60 dB of compression free dynamic range. I maintain that the limitations lie not with my particular speaker choice, but much more so with the actual recording, preamp noise floor w.r.t. the actual volume setting (the smallest detials in any preamp will increasingly be lost as the volume is turned down), and the noise floor of my humble abode.

I agree the human ear is an amazing device, and yes after time will compress its own dynamic range in the presence of high rms acoustic energy. With today's "perfect sound forever" digital recordings, this unfortunately happens much more often...
To have extremely wide dynamic range speakers like the Masters, for instance would be especially vexing (although I must admit a problem I could live with): What content is actually out there, save using them in live settings, to actually exercise such performance potential?
This applies to your wide dynamic range low distortion actives as well.
There is such an abysmally small quantity of wide dynamic range recordings relative to the "hot" recordings out there I think most of us get more fed up with the average sound of THAT ratio, and not any particular colorations or slight shortcomings our gear presents us.

It is a harsh reality really. It's like having a Ferrari in a city. Sure it looks good but how often can you really open it up?

The Evidence Masters are an exceptional speaker not "most speakers". Compression is a huge issue in speakers....at elevated levels (say peaks of 95 db+ at the listening position) the cones quickly exceed Xmax and you get all kinds of compression as well as distortion. The voice coil heats up also adding several more DB of compression. This produces a very dull and distorted sound at realistic live music levels - even if you have a humungous amplifier! If the speaker is heavily compressed and distorted then it is also unable to produce low level sounds simultaneously with loud sounds (distortion can bury the soft sounds). Furthermore the background noise floor may be somewhere approaching 30 db in a fairly quiet environment, if 95 db is where the speaker starts heavily compressing then this is a mere 65 db dynamic range above the noise floor in the room....nowhere near the theoretical 96 db of the CD across the full frequency range.

With Speakers like the Dynaudio Master you may approach the dynamic range of the CD, as these will play very loud and will not compress like most speakers. (120 db uncompressed peaks less 30 db noise floor is close to 90 db dynamic range) Note that Dynaudio have only sold 1500 of these speakers - so this is NOT most speakers!

I agree the human ear is an amazing device, and yes after time will compress its own dynamic range in the presence of high rms acoustic energy

The ear hairs move around in response to accoustic waves....this triggers nerve bundles that send impulses to the brain. Inherently the system is "digital" in the sense that it takes time for nerve bundles/hairs to reset...this means that loud sounds and sounds of certain frequencies will mask other sounds. The issue is extremely complex but has been extensively studied....some of the amazing compression algorithms such as MP3 exploit the digital features of the ear by leaving out stuff that pyschoacoutics has shown that we can't hear or are least likley to hear (due to masking).

When a speaker starts distorting like crazy or you have oodles of harmonic distortion then this will also begin to mask stuff that the musicians/soudn engineer intended you to hear. Careful selection of timbre, arrangement and selection of instruments, microphone placement, expert adjustment on tonal balance (EQ), reverberation and dynamic range are what allow you to hear the most in a musical piece with your digitally limited hearing!

Check out Grace Jones "Slave to the Rhythm - Hot Blooded Mix" for something that is astonishingly audible.
Thanks Shadorne for the info and recomendation.
Here is another article I tried posting 3 x with no luck...


Can you imagine how different the high end audio landscape would be with consistently realized high dynamic cd's?
I bet for one there would be much less equipment swapping...
I bet for one there would be much less equipment swapping...

Indeed I think it is important to recognize just how much a good recording can do.

The easiest way to sell any piece of gear is to play only great recordings. The demo disc is the salesman's "trick #1" to get uninitiated into an impulsive purchase. The poor dupe ends up lugging his new prize piece of gear back home and sadly finds that very few of his recordings sound the magical way the demo disk sounded, fantastic track after track!

Trick #2 is to turn the volume up slightly on gear that you are trying to move and turn the volume down slightly on gear that you don't want the listener to like. Works like a dream on A/B sessions!