Not to argue, but to understand.
I am not driving them near the maximum level JBL says they will play (126dB) in the case of the 4350’s and if the issue is “dynamics”, and is not related to HD, what is responsible for the change / increase in mid bass, and the decrease in mid bass clarity while the rest of the system plays clean?
Better / lower distortion woofers definitely improve the situation but the Everest woofers are not meant to play louder than the 2235’s.
Harmonic distortion / added higher frequency content generated by the driver is what audibly gives away the position of an otherwise properly crossed over subwoofer so I just can’t yet buy the statement that HD is inaudible. Increased HD changes the spectral ballance of a driver.
If this one of those discussions of what we can and can’t measure, if HD isn’t the measurable cause that creates this phenomenon, what is?
Barry.
The moving cone seems to be a thin sheet of flabby material, small inaccuracies in the cone geometry are triggering large signals.
http://beyma.com/uploads/descargas/1352741048.pdf
That was a very informative document!
Strange that I've never come across it before.
Edit:
Think it depends on the frequency spectrum involved, at low frequencies especially there seem to be a lot of people who prefer harmonic distortion because that is what they are used to. We adapt to our surroundings, and we make our preferences based on what we have adapted to.
Strange that I've never come across it before.
Edit:
Think it depends on the frequency spectrum involved, at low frequencies especially there seem to be a lot of people who prefer harmonic distortion because that is what they are used to. We adapt to our surroundings, and we make our preferences based on what we have adapted to.
Last edited:
Things have particularly retained my attention (except easy to understand equations with derived numbers) :
All the cone parts are not accelerating the same way.
In the conclusion :"Despite the fact that using a three degree of freedom model may be a simplification, based on the axial modes; those models based on the moving assembly as a single mass are oversimplified"
And in the conclusion :"The apparent paradox that some high renowned loudspeakers have high nonlinear moving assemblies should be accepted by those who are not familiar with nonlinearities"
All the cone parts are not accelerating the same way.Yes, all materials flex, and all constructions have a resonant frequency.
In the conclusion :"Despite the fact that using a three degree of freedom model may be a simplification, based on the axial modes; those models based on the moving assembly as a single mass are oversimplified"
It is a sum of many parts. It is not a single lump of material.
And in the conclusion :"The apparent paradox that some high renowned loudspeakers have high nonlinear moving assemblies should be accepted by those who are not familiar with nonlinearities"
Yes, because it's really difficult to deal with, especially on larger drivers.
Just really like that document, it is so nice to see how they evaluate the cone as a non-piston, but a flexible sheet of many different materials flowing back and forth.
Last edited:
Peter Larsen is one of loudspeaker driver gurus
Design Consulting - Peter Larsen can develop your speaker
FINECone demo
YouTube
Design Consulting - Peter Larsen can develop your speaker
FINECone demo
YouTube
Could you say why they modeled the coil mechanical energy with mass*xmax'', i don't understand the choice of the second order derivative
It should be painfully expensive !
RE Doppler distortion:
This is not just "the cops approaching". It is the cops repeatedly approaching and driving away many times per second ! I.e. in the case of a loudspeaker the higher frequency content is frequency modulated by the lower frequency content (where the cone must move farther for the same SPL).
FM modulation does always generate sidebands. These sidebands are of course also subject to audible masking. Colloms once wrote ein a book that it is irrelevant even with wideband drivers if the excursion stays below a certain amounf. I can't remember whether it was +-3mm or +-6mm p-p.
Pesonally I like speakers whose cones carrying midrange information don't visibly move when looked at from the listening seat.
Regards
Charles
This is not just "the cops approaching". It is the cops repeatedly approaching and driving away many times per second ! I.e. in the case of a loudspeaker the higher frequency content is frequency modulated by the lower frequency content (where the cone must move farther for the same SPL).
FM modulation does always generate sidebands. These sidebands are of course also subject to audible masking. Colloms once wrote ein a book that it is irrelevant even with wideband drivers if the excursion stays below a certain amounf. I can't remember whether it was +-3mm or +-6mm p-p.
Pesonally I like speakers whose cones carrying midrange information don't visibly move when looked at from the listening seat.
Regards
Charles
Could you say why they modeled the coil mechanical energy with mass*xmax'', i don't understand the choice of the second order derivative
One of my weakest skillsets is math. If you are asking for my very limited and general "guesstimation" here it is:
They modeled the coil mechanical energy with xmax because the coil is the only single component with pistonic behaviour, and the mechanical energy transmitted to the cone is limited by xmax.
Edit:
It is a simplification. They probably settled on using that after a long and heated debate, where some just wanted to go the easy route, some just did not want to argue, and one or two individuals held on to their slightly more accurate but overly complicated math models.
Last edited:
One of my weakest skillsets is math. If you are asking for my very limited and general "guesstimation" here it is:
They modeled the coil mechanical energy with xmax because the coil is the only single component with pistonic behaviour, and the mechanical energy transmitted to the cone is limited by xmax.
Edit:
It is a simplification. They probably settled on using that after a long and heated debate, where some just wanted to go the easy route, some just did not want to argue, and one or two individuals held on to their slightly more accurate but overly complicated math models.
IMHO, if the Xmax trajectory is derivable, it is because this displacement is not linear at all and can be considered as a continuous function.
Displacement is not linear. The cone, dustcap, surround and spider (and to a limited extent, the mass of the coil, the internal cavities and air resistance inside the driver) will contribute to variations in mechanical resistance throughout the travel/displacement. Xmax is the limit of decaying rate of energy (or something) because of the coil/gap. Going above xmax will significantly reduce the control of the driver.
Edit:
While trying to go above xmech will lead to complete destruction :-D
Last edited:
The maximum linear displacement (Xmax) is curvilign and the Bl (motor strength) is also curvilign (with only one gap).
Linearity is a concept (as some mathematic numbers) it don't exist in real life.
As everything else, there is no rule without exception, it may be that Linearity applies to Murphy's law?
simplification have more limits than complexity.
You can't cure humanity... barely everyone wants to know what is hidden in the well honed solution.
i have a painting in mind...
We have the behavioral pattern of a form of virus. We are very effective vessels for bacteria. Our genetic code is simpler than some grain types.
Like a well designed loudspeaker can be made of cheap, common parts but still have the capacity to sound good. I do not have much interest in paintings, but to listen to a Musician that has lived, evolved, experienced, and can truly sing with the instrument he or she utilizes. To be able to accurately portray emotion or incidents explicitly with the use of an instrument. So that you can see with your minds eye what he or she is portraying.
It must be the same with an experienced Loudspeaker designer, to be able to design and make drivers that have exemplary specifications take time and experience. It is also an art.
Edit:
More in line with the thread: One of the nicest looking 10" drivers with very good values must be the SEAS H1411-08 A26RE4, I have not seen any distortion plots, but can not imagine much trouble over the intended freq response.
Like a well designed loudspeaker can be made of cheap, common parts but still have the capacity to sound good. I do not have much interest in paintings, but to listen to a Musician that has lived, evolved, experienced, and can truly sing with the instrument he or she utilizes. To be able to accurately portray emotion or incidents explicitly with the use of an instrument. So that you can see with your minds eye what he or she is portraying.
It must be the same with an experienced Loudspeaker designer, to be able to design and make drivers that have exemplary specifications take time and experience. It is also an art.
Edit:
More in line with the thread: One of the nicest looking 10" drivers with very good values must be the SEAS H1411-08 A26RE4, I have not seen any distortion plots, but can not imagine much trouble over the intended freq response.
Last edited:
Like everyone my body is full of plasmids that constantly reprogram my ADN cells code.
Don't forget that for 120€ i can also have a well designed 15 inches PA woofer plus a very well designed small hifi medium.
Focus Elswhere!
Most audible distortions (departures from a realistic performance) are beyond your control. They relate to the acoustics of the recording venue, miking techniques employed, the technology used to record it, and mix-down details used to produce the master recording, a copy of which is the source you will be listening to. Beyond this, the acoustics of your listening space and the number and placement of loudspeaker units within it is next. This is followed by signal processing facilities available in your system. Next is the directivity of the loudspeaker drivers used and the crossover points selected, the drive signal filtering, and enclosure design details. Last and least important, are the loudspeaker distortion products that measure, say less than 10%. At the low levels used in a domestic listing space, most are inaudible or masked by the characteristics of the original music signal that has already been recorded. Dr. Bose figured this one out a long time ago.
Regards,
WHG
Most audible distortions (departures from a realistic performance) are beyond your control. They relate to the acoustics of the recording venue, miking techniques employed, the technology used to record it, and mix-down details used to produce the master recording, a copy of which is the source you will be listening to. Beyond this, the acoustics of your listening space and the number and placement of loudspeaker units within it is next. This is followed by signal processing facilities available in your system. Next is the directivity of the loudspeaker drivers used and the crossover points selected, the drive signal filtering, and enclosure design details. Last and least important, are the loudspeaker distortion products that measure, say less than 10%. At the low levels used in a domestic listing space, most are inaudible or masked by the characteristics of the original music signal that has already been recorded. Dr. Bose figured this one out a long time ago.
Regards,
WHG
I never said that HD was not audible. I could certainly design a loudspeaker where it was, but I could also design one where it wasn't. I prefer to do the later, although some might "prefer" the former.
My point is this:
1) Up until the loudspeaker system is clipping (for lack of a better word, maybe XMax, although that term is also ill-defined) the HD in a "good" loudspeaker is not an issue. And this "clipping" can certainly be well below a loudspeakers "rating" since that rating is usually a thermal limit, not a linearity one.
2) in no case can one use THD or IMD as a metric to say that one loudspeaker sounds better than another. A loudspeaker with 5% THD could sound much better than one with 1% THD and visa-versa. As a measure of quality THD and IMD are meaningless.
Your person perceptions are not reliable enough to make a strong case because you know what you expect to hear and hence that is exactly what you do hear. Our testing was all blind. So I cannot explain what you hear in your tests. I only know what conclusions one can draw from the controlled testing that we did.
Doppler distortion is a real measureable effect, but it is unlikely to ever be audible due to its low order of nonlinearity - it will be masked.
What needs to be understood about masking is that it increases (widens) with SPL. This means that as the distortion goes up with level so does the masking. Some effects, like diffraction, become unmasked at higher SPL, which means that at some level diffraction will always be audible.
This is perhaps what 1audiohack is hearing in his system. It is not HD. I don't really know. I do know that in my system reducing all forms of diffraction makes the system sound much cleaner especially at higher SPLs.
What needs to be understood about masking is that it increases (widens) with SPL. This means that as the distortion goes up with level so does the masking. Some effects, like diffraction, become unmasked at higher SPL, which means that at some level diffraction will always be audible.
This is perhaps what 1audiohack is hearing in his system. It is not HD. I don't really know. I do know that in my system reducing all forms of diffraction makes the system sound much cleaner especially at higher SPLs.