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Topic: Dynamic equalizer (Read 9142 times) previous topic - next topic
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Dynamic equalizer

I have question about dynamic equalizers. I've found that it's used in some home theatres and that also that there is website : http://www.audyssey.com/technology/dynamicEQ.html promoting Dynamic EQ. It is based on Fletcher–Munson curves and is has impact on how loudness is controlled. Is dynamic eq really improving the audio and if so are there some software dynamic eq (maybe one for foobar2000)?

Dynamic equalizer

Reply #1 –

i don't see much new or of value here.  "Loudness" compensation has been available on home recievers for fifty years or more.  The Fletcher Munson curves are nothing new and controls that vary the correction according to level are nothing new either.

The Onkyo A/V receiver I bought yesterday has it.  I turned it off and notice no problems caused thereby.  I would ignore this entirely as a factor in making purchasing choices if I were you.  I certainly did.  You can always find a web site that touts any trivial technology as being the ultimate new idea so I would ignore that too.

If it is available in a cheap receiver it is on a chip set somewhere and should basicly cost you nothing much so no need to avoid it as long as your system lets you shut it off.

Just my two cents worth.
Ed Seedhouse
VA7SDH

Dynamic equalizer

Reply #2 –
Quote from: Ed Seedhouse on
The Onkyo A/V receiver I bought yesterday has it.  I turned it off and notice no problems caused thereby.  I would ignore this entirely as a factor in making purchasing choices if I were you.  I certainly did.  You can always find a web site that touts any trivial technology as being the ultimate new idea so I would ignore that too.


What interesting is about this technology is that it improves loudness for low volumes so maybe that’s reason you didn't notice any change when it was turned off. This is main reason I've got interested on the dynamic eq.

Dynamic equalizer

Reply #3 –
Quote from: wisodev on
What interesting is about this technology is that it improves loudness for low volumes so maybe that’s reason you didn't notice any change when it was turned off. This is main reason I've got interested on the dynamic eq.


They already knew how to do that back in the 1950s.  Sorry if I find it hard to get excited about it. If they are touting this as something "new" they are miseading you.




Ed Seedhouse
VA7SDH

Dynamic equalizer

Reply #4 –
If you click the link on the site about the products that feature this "Dynamic EQ" that has however many decades of research put into it and is touted as being so great, you'll note that 90% of their products from various brands have it. In fact, every receiver / amp / stereo with a loudness feature is listed.

Their dynamic EQ is pretty much just the big Loudness button that I even have on my 14 year old Pioneer Pre-amp. It won't be anywhere near as exact as that website touts it to be as not only do your ears but your speakers also have varying response curves at volumes lower (or higher) than what they were intended to be listened to. Do not get used to using it either as chances are, you're losing sound quality, adding needless compression, and I know a fair few people that grow fond of loudness because it makes up for their speakers' shortcomings. (Much like WMP's SRS WOW junk, or any bass expanding / treble sharpening DSP's)

Dynamic equalizer

Reply #5 –
My first post here:

Dynamic bass equalization is very important.

For bass only Parametric EQ is more important.

Unfortunately, the bass adjustments needed to
offset the Fletcher-Munson effect will change
as the average volume changes.

The Fletcher-Munson effect is strongest
in the 25-50Hz. octave. ...
... while variable loudness controls
that were used in some components
many decades ago, decided to target
the 50-100Hz. octave, which is more audible
and less dangerous for cheap speakers!

There is no way to use ONE loudness control
or ONE EQ setting to get a good balance of bass,
mid-range and treble on all recordings, even if
the average SPL was constant.

The recordings themselves have a wide range of
bass loudness (relative to mid-range and treble frequencies).
A lot of variation among rock CDs but
not that much in jazz and classical CDs.

A 1950's rock CD may have such weak bass that you can
barely hear the bass guitar ... while a modern R&B
CD may have such loud bass that you want to turn it down.

My solution is to use a satellite - subwoofer system.

As a "bassnut" who mainly listens to rock music,
I will adjust my subwoofer level, if necessary,
for each CD to get a bass-mid-range-treble balance
that sounds right to my ears. 

I tend to listen in the 75-80dB range, but if I ever use
a lower background music volume, I'll turn up
the subwoofer level (70Hz. 24dB/octave crossover)
to compensate for the difficulty hearing deep bass
at low volumes.

When you listen to a wide variety of music at a wide
variety of volumes, there's no way ONE control, or
ONE EQ setting, could compensate for the Fletcher-Munson
effect on all recordings.  But any attempt to compensate
for the difficulty of hearing deep bass at low volumes
is probably better than doing nothing.

Dynamic equalizer

Reply #6 –
This is NOT traditional loudness compensation.  Traditional loudness compensation is linear-constant bass boost that depends only on the volume control setting (not the signal level)...    Dynamic compensation adjusts the boost depending on the actual program volume level.  At low listening levels, all of the bass is boosted, but quiet passages get more bass boost than louder passages. (It's actually dynamic compression of the bass.)

This actually does make sense to me...  At low levels and low frequencies  you get the perception of dynamic expansion.  You can't completely compensate for that with linear bass-boost.  You need to boost and compress the bass.

It wouldn't make much difference with modern "loudness wars" CDs & MP3s, which don't have any dynamics!

I've never heard this system, so I don't know if it really sounds that much better than traditional loudness compensation.  It is calibrated to the acoustical level and the room acoustics, and that alone should be an improvement over a system that simply relies on the volume control setting. 

Quote
When you listen to a wide variety of music at a wide variety of volumes, there's no way ONE control, or ONE EQ setting, could compensate for the Fletcher-Munson effect on all recordings.
It's not designed to compensate for the recording (or for personal taste).  It's supposed to compensate for the way human perception of frequency balance is distorted at low levels. 

Quote
But any attempt to compensate for the difficulty of hearing deep bass at low volumes is probably better than doing nothing.
I agree.

Dynamic equalizer

Reply #7 –
edit: mod delete please

Dynamic equalizer

Reply #8 –
Quote from: Ed Seedhouse on
Quote from: wisodev on
What interesting is about this technology is that it improves loudness for low volumes so maybe that’s reason you didn't notice any change when it was turned off. This is main reason I've got interested on the dynamic eq.


They already knew how to do that back in the 1950s.  Sorry if I find it hard to get excited about it. If they are touting this as something "new" they are miseading you.



Um, no, Ed, a proper loudness correction involves time-varying adjustment. Nothing in the 1950's did this. The "loudness" controls on the 1960's receivers, etc, were fixed to a given shape, given a volume control setting.

A proper adjustment, etc, however, is quite complex and involves time-varying filtering that is sensitive to the actual signal spectrum.  There are several such algorithms available hither and yon.
-----
J. D. (jj) Johnston

Dynamic equalizer

Reply #9 –
Quote from: DVDdoug on
Traditional loudness compensation is linear-constant bass boost that depends only on the volume control setting (not the signal level)...    Dynamic compensation adjusts the boost depending on the actual program volume level.

Sounds like dynamic compensation should be an audio creation tool rather than a playback tool.

Dynamic equalizer

Reply #10 –
Quote from: Woodinville on
Quote from: Ed Seedhouse on
Quote from: wisodev on
What interesting is about this technology is that it improves loudness for low volumes so maybe that’s reason you didn't notice any change when it was turned off. This is main reason I've got interested on the dynamic eq.


They already knew how to do that back in the 1950s.  Sorry if I find it hard to get excited about it. If they are touting this as something "new" they are miseading you.



Um, no, Ed, a proper loudness correction involves time-varying adjustment. Nothing in the 1950's did this. The "loudness" controls on the 1960's receivers, etc, were fixed to a given shape, given a volume control setting.

A proper adjustment, etc, however, is quite complex and involves time-varying filtering that is sensitive to the actual signal spectrum.  There are several such algorithms available hither and yon.


The encouraging thing is that now that DSPs and automated room/speaker calibration facilities are becoming common receiver features, one could actually implement a useful loudness contour facility with a negligable incremental economic cost. It may have even partially or largely happened. ;-)

Dynamic equalizer

Reply #11 –
Quote
Sounds like dynamic compensation should be an audio creation tool rather than a playback tool.
  Nooooo!  You're compensating for effects at lower playback level, and you have no idea of playback level during "creation".  During production, the assumption is that the listener is listening at "proper levels", and under these conditions, no loudness compensation is needed.

The whole idea is this...  Say the original live performance was 95dB SPL (or it was mixed at 95dB SPL).  You play back the recording at 70dB in your living room.  The perception is that you turned-down the volume PLUS you turned down the bass. 

Of course this is perfectly natural, we are used to it, and we don't really get the impression that the bass was turned down.  But, the tonal balance IS changed and we might say something like,  "It just doesn't sound right 'till I turn it up!".  The music will sound somewhat "more natural" at lower levels if we use loudness compensation.

Dynamic equalizer

Reply #12 –
Quote from: bandpass on
Quote from: DVDdoug on
Traditional loudness compensation is linear-constant bass boost that depends only on the volume control setting (not the signal level)...    Dynamic compensation adjusts the boost depending on the actual program volume level.

Sounds like dynamic compensation should be an audio creation tool rather than a playback tool.


Only if the producer knows what level you are going to use in playback, eh?

This is a function that belongs at the very end of the chain.
-----
J. D. (jj) Johnston

Dynamic equalizer

Reply #13 –
Quote from: Arnold B. Krueger on
The encouraging thing is that now that DSPs and automated room/speaker calibration facilities are becoming common receiver features, one could actually implement a useful loudness contour facility with a negligable incremental economic cost. It may have even partially or largely happened. ;-)


Why, Arnold, yes, in fact I believe several different groups have made this largely happen.  How ever did you guess. 

Unfortunately, at least two of them have been very nearly stupidly remiss (or in one case absolutely stupidly remiss) in actual marketing of the technology.
-----
J. D. (jj) Johnston

Dynamic equalizer

Reply #14 –
YOU WROTE:
"This is NOT traditional loudness compensation.  Traditional loudness compensation is linear-constant bass boost that depends only on the volume control setting (not the signal level)...    Dynamic compensation adjusts the boost depending on the actual program volume level.  At low listening levels, all of the bass is boosted, but quiet passages get more bass boost than louder passages. (It's actually dynamic compression of the bass.)"

RG
It's hard to guess what a sound processor does without an audition,
but I guess we could discuss the theory behind it
versus the bass problems we hear at home?

Maybe I misunderstood the product
as something that applied a different level
of loudness compensation based on
the average SPL of the music
(that would be the direct link to the Fletcher Munson effect
-- measure the average SPL of the music frequencies above the bass,
and then adjust the bass level for a better balance
of bass, mid-range and treble). 

Given the increasing amount of dynamic compression in rock music today,
why would a listener want MORE compression? 

I disagree with more compression of the bass frequencies.

Doing that will change the bassline,
so the listener will not hear
what the bass musician intended. 

There is already one big problem
with bass frequency response
in most rooms from standing waves
-- the bassline is usually far from
what the musician played in the studio.

That problem can be reduced with
lots of bass traps and bass parametric EQ.

I think the next bass problem to solve is the
subjective balance of bass, mid-range and treble.

That balance can seem subjectively wrong
at low volumes (Fletcher-Munson effect), or in some
recordings where the bass is recorded unusally weak,
or unusually loud. 

I still believe there are so many variables
affecting the bass -mid-range-treble balance
that the best solution is using the volume control on the
subwoofer (hopefully with a remote control)
to subjectively "fix" EACH recording.

I find it easy to believe that a processing device
could be helpful, but hard to believe that it would get
the very subjective bass-midrange-treble balance
"right" for each recording (or each song)
no matter what average volume the listener preferred.

My experience with sound processors is they sometimes
work well and simetimes make the sound quality worse:

A long time ago in the old days of vinyl pre-1985,
I tried and later sold two sound processors:
(1) A three-band dynamic range expander, and a
(2) A subharmonic synthesizer
(I began building DIY subwoofers in the early 1980's)

The dynamic range expander sometimes made a the sound quality better
on vinyl and sometimes worse (strange that it could still be useful today
for over-compressed compact discs)

The subharmonic synthesizer was fun "subwoofer exercise"
on some songs and just made other songs bass heavy
-- it never sounded "natural" in any way
(I believe these synthesizers are sometimes used
with bass guitars today)

Dynamic equalizer

Reply #15 –
Richard,

I agree with most of what you're saying.  I'm NOT going to run-out and buy receiver with this feature!  I'm just arguing that the theory is valid.

Quote
Given the increasing amount of dynamic compression in rock music today,
why would a listener want MORE compression?
I agree.  But, if there are no dynamics in the program material, the "dynamic" part of this system won't kick-in, and there will be no compression and no harm.  And, the system won't kick-in if you're listening at the "proper" volume/gain level...  Your orchestrical music will remain dynamic and and uncompressed.  Quiet passages will not be "adjusted" IF you're listening at "live" volume levels. 

Quote
I disagree with more compression of the bass frequencies.

Doing that will change the bassline,
so the listener will not hear
what the bass musician intended.
But the problem is...  By simply turning down the volume, the listener won't hear the bass as intended.   If you study the Fletcher-Munson curves, you will see that compression is required if you want to completely compensate for the effect.  Just looking at the curves, you can see that the curves are squeezed together (compressed) on the left (bass) side.  This shows that compression is required in order to perceive "equal loudness".

----------------------
Here's an example (with very rough approximations to demonstrate the principal):

A guitar player and bass player each play two "notes".  The guitar player plays 440Hz at 100dB and 440Hz at 93dB.  The bass player plays 44Hz at 100dB and 44Hz at 93dB. 

If you reduce the volume by 20dB, you hear this:
440Hz 80dB (as expected)
440Hz 73dB (as expected)

44Hz 72dB  (~8dB perception error)
44Hz 62dB  (~11dB perception error)

You will still hear a 6dB difference between the two guitar notes.  But, you have two problems with the bass.  The bass now sounds 8 to 11dB quieter than the guitar, and the 6dB difference between the two guitar notes sounds like a 10dB difference.  To correct for this, we need to boost the 1st guitar note by 8dB and the 2nd guitar note by 11dB.  That requires bass boost AND compression!

Dynamic equalizer

Reply #16 –
YOU WROTE:
"Here's an example (with very rough approximations to demonstrate the principal):

A guitar player and bass player each play two "notes". 
The guitar player plays 440Hz at 100dB and 440Hz at 93dB. 
The bass player plays 44Hz at 100dB and 44Hz at 93dB. 

If you reduce the volume by 20dB, you hear this:
440Hz 80dB (as expected)
440Hz 73dB (as expected)

44Hz 72dB  (~8dB perception error)
44Hz 62dB  (~11dB perception error)

You will still hear a 6dB difference between the two guitar notes. 
But, you have two problems with the bass. 
The bass now sounds 8 to 11dB quieter than the guitar,
and the 6dB difference between the two guitar notes sounds
like a 10dB difference.  To correct for this, we need to boost the
1st guitar note by 8dB and the 2nd guitar note by 11dB.
That requires bass boost AND compression!"

RG replies:
I wouldn't use your example to defend a processor for several reasons:

(A) Fletcher Munsion curves are averages of subjective listening
created a long time ago -- to me that's three strikes:
(1) averages
(2) subjective
(3) data from a long time ago

(B) A bass guitar note has as much, or more energy, in the harmonics as
in the fundamental tone.  That makes the subject much more complicated
than a simple sinewave tone which your analysis implies.

© It's so difficult to hear music content in the 25-50Hz. octave
that 60dB or lower may be under the threshold of audibility.
- And if the music is complex with a lot of instruments playing,
the threshold of audibility for the 25-50Hz. octave might be 70dB

At reasonable volumes while listening to music
there is definitely a need for some bass compression
(i.e.; loudness compensation), with some  compression
in the 50-100Hz. octave and a lot of compression
in the 25-50Hz. octave.

If a signal processor can do that -- that's great news!

I personally prefer getting out of my chair to adjust my
subwoofer volume to create a better subjective mix
of bass / mid-range / treble, even if I have to second-guess
the recording engineer.  That's also my only regular
"exercise program", as I usually listen to one song per CD
at a time, and will consider adjusting the subwoofer level,
if necessary, with EVERY SONG.

I am unusually sensitive to bass frequencies:
- If a bass note seems too loud from an uncontrolled standing wave,
or the bass is subjectively weak at low volumes, I go berserk
and have to do something.  I am often surprised that
"high end" audiophiles will spend $1000's on wires,
while ignoring room acoustics and the Fletcher-Munson effect.
.


Dynamic equalizer

Reply #17 –
most mid/high-end surround recievers nowadays have relatively advanced dynamic compression systems that work very well. They will give you the perception of more balanced sound even at lower listening volumes.  I guess the only downside is that those of you who rely on walking from the couch to the subwoofer to make adjustments between each track may have a problem.
Thorbjorn

Dynamic equalizer

Reply #18 –
Quote
At reasonable volumes while listening to music
there is definitely a need for some bass compression
(i.e.; loudness compensation), with some compression
in the 50-100Hz. octave and a lot of compression
in the 25-50Hz. octave.

If a signal processor can do that -- that's great news!
Bingo!  That's exactly what this system does! (or claims to do)  And, that kind of processing is trivial in software/firmware.

Dynamic equalizer

Reply #19 –
I usually enjoy the dynamics of many movies, where to hear the quieter dialogue you need the volume up to a level where explosions & the like almost blow the windows out, but there are times when this is not fair on others nearby. I have often wanted a (switchable) way of 'turning up ' quiet scenes whilst 'turning down' the action scenes.

In the unlikely event I ever have enough money to get an AV amp for watching movies (DVDs), is this the sort of thing I should be looking out for?