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Multi-Way Conventional loudspeakers with crossovers

Some speaker driver measurements...
Some speaker driver measurements...
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Old 17th November 2019, 04:07 PM   #531
briskly is offline briskly  United States
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Originally Posted by Oneminde View Post
Determining factors:
On- and off axis response.
Impedance response.
Harmonic content.
Inter Modulation Distortion.
Transient response, Impulse Response (Step respons) & Energy Time Curve
Impedance is one of those things that mostly affects how you get to the desired acoustical result, since we are usually more concerned with the pressure level some distance from the speaker.
Harmonic and modulation products stem from the fundamental nonlinearity of the test system. Putting in one or several tones is just an easily quantified means of probing its characteristics.
Step response, spectral decay, ETC, and so on amount to alternative representations of the information provided by the impulse/frequency response. I do have to ask what behavior is made apparent that you couldn't clearly see under the existing representations.

Did SBA ever mention they were going to sell the 13.5 inch driver? I saw that they had prototypes that were shelved from a lack of perceived market interest.

Last edited by briskly; 17th November 2019 at 04:37 PM.
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Old 17th November 2019, 04:10 PM   #532
Zvu is offline Zvu  Serbia
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Originally Posted by Oneminde View Post
I do not disagree, however.... when it comes to the observed acoustic event, we are not dealing with magic.

Determining factors:
On- and off axis response.
Impedance response.
Harmonic content.
Inter Modulation Distortion.
Transient response, Impulse Response (Step respons) & Energy Time Curve

The party trick is to mate the driver to the "right" cabinet and properly deal with internal reflection as well as diffraction. Basically, the cleaner everything is in terms of low distortion the better. I am aware of the subjective aspects which apply to every engineer/listener (no exceptions). As I mentioned earlier: An acoustic instrument produce music while a loudspeaker REPRODUCE music - The complex part (if you like) is the subjective aspects of what sounds good or not and the issue with that is, its subjective. Its virtually impossible to agree, but sometimes, you will find camps were they mostly agree but never fully. So in a way, subjectively talking about which driver(s) or loudspeaker(s) that is excellent or stellar is meaningless. The hope and real endeavors are achieved in the objective aspects because it is non subjective.
And it can be done even without dsp and multichannel - with a little knowledge and effort involved. I really enjoyed John Darko's comparison between Kii3 vs Kef Reference 1 + Hegel H590 amp - active DSP vs passive system. Kinda new before watching who will win but it was fun watching nevertheless.
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Last edited by Zvu; 17th November 2019 at 04:16 PM.
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Old 17th November 2019, 04:19 PM   #533
cotdt is offline cotdt  United States
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The cone material that they need to use is hardened steel. Its stiffness to weight ratio is significantly better than aluminum, and the breakup frequency would be extremely high. It's also extremely consistent material.
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Old 17th November 2019, 04:26 PM   #534
Zvu is offline Zvu  Serbia
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Originally Posted by cotdt View Post
The cone material that they need to use is hardened steel. Its stiffness to weight ratio is significantly better than aluminum, and the breakup frequency would be extremely high. It's also extremely consistent material.
#thuglife
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Old 17th November 2019, 04:30 PM   #535
Oneminde is offline Oneminde  Sweden
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Originally Posted by briskly View Post
I do have to ask what behavior is made apparent that you couldn't clearly see under the existing representations.

Did SBA ever mention they were going to sell the 13.5 inch driver? I saw that they had prototypes that were shelved from a lack of perceived market interest.
In terms of behavior, the more pistonic or linear motion the driver has with lower internal resonance, the cleaner it will reproduce the signal, so in terms of what splendid drivers need to have or do, its fairly obvious. Achieving it IRL is.. well, challenging to say the least. Pistonic and linear behavior is and has to be monitored or measured in several ways. Plotting the Bl curve is another nice way to add to the complexity. SBA might have found a very nice material and implementation through the TeXtreme. But we need impartial 3rd parties to test the driver(s) to avoid to much biased results.

What we know so far is that the 13.5" exist as a prototype and that me among others have expressed and interest. Until and if Ulrik (USXX) provide more info or updates, what will happen is uncertain. I for one hope it will be released under the TX line.
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Old 17th November 2019, 04:37 PM   #536
wolf_teeth is offline wolf_teeth  United States
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Originally Posted by cotdt View Post
The cone material that they need to use is hardened steel. Its stiffness to weight ratio is significantly better than aluminum, and the breakup frequency would be extremely high. It's also extremely consistent material.
I hope that's a joke. Steel would be constantly attracted to the magnet, and eventually ruin the suspension.
Wolf
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Old 17th November 2019, 05:02 PM   #537
audiogod66 is offline audiogod66
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I hope that's a joke. Steel would be constantly attracted to the magnet, and eventually ruin the suspension.
Wolf
Can't beat science those so called aluminium billet cones from YG Acoustic are supposed to be terrific but somehow I cannot see the boss allowing Wolf to take apart his $5000 drivers only to discover there from a secret HiVi Swan factory in Guangdong 😁
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Old 17th November 2019, 05:16 PM   #538
Oneminde is offline Oneminde  Sweden
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Can't beat science those so called aluminium billet cones from YG Acoustic are supposed to be terrific but somehow I cannot see the boss allowing Wolf to take apart his $5000 drivers only to discover there from a secret HiVi Swan factory in Guangdong 😁
How is that possible ? The motor comes from ScanSpeak Illuminator series and the cone is produced in house or by a neighbor facility. There is nothing secret about the YG Acoustics BilletCore Cone. I have personally held the cone in my hands and inspected it.
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Old 17th November 2019, 05:58 PM   #539
briskly is offline briskly  United States
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Originally Posted by Oneminde View Post
In terms of behavior, the more pistonic or linear motion the driver has with lower internal resonance, the cleaner it will reproduce the signal, so in terms of what splendid drivers need to have or do, its fairly obvious. Achieving it IRL is.. well, challenging to say the least. Pistonic and linear behavior is and has to be monitored or measured in several ways. Plotting the Bl curve is another nice way to add to the complexity. SBA might have found a very nice material and implementation through the TeXtreme. But we need impartial 3rd parties to test the driver(s) to avoid to much biased results.
The membrane as a surface with a uniform velocity and the complete driver's nonlinear behavior are not so strictly related. Modes, higher orders and otherwise, are normally tackled in the linear limit, even though certain types of modes can set up interesting types of distortion. But what relation are you trying to draw between rigidity and the measurement?
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Old 17th November 2019, 07:01 PM   #540
Oneminde is offline Oneminde  Sweden
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But what relation are you trying to draw between rigidity and the measurement?
Straight forward, rigidity mean stiffness or compliance (how much an object yield or confirm to an external force). This is strictly applied to the cone in this instance. Low compliance mean that an external force have low influence on the structure and high compliance mean it has a high influence. Untreated paper has high compliance and diamond has low compliance. But material is only one aspect. Rigidity can also come from the shape or how material is distributed, but, to keep things simple. The stiffer the cone is the less it will deform and hence less nodes and anti-nodes.

Click the image to open in full size.

As seen in the picture above (Titanium to the left and thin ply carbon diaphragm on the right (TeXtreme)), the node or cone breakup behavior is very different between the solid Titanium cone and carbon weave. The construction is also very different. The former cone rely on one material while the weave rely on at least 2, the weave + resin or glue (bonding agent). The weave create an interference pattern while the Titanium does not, the weave has resonance canceling properties similar to a sandwich cone which use at least two different material properties, like what Vandersteen does.

Quote:
“Pistonic” refers to the motion of the driver cone in response to the audio signal from the driver’s voice coil. If the driver cone stays rigid and moves in and out in truly pistonic fashion, distortion is avoided and the purest replica possible of the signal from the amplifer is produced by the speaker. If any part of the cone flexes or bends in the opposite direction of the signal, part of the cone is out of phase, and distortion is output from the loudspeaker.
A loudspeaker driver has one job, to induce vibrations that propagates as an audible wave of pressure, through a transmission medium (air) and is translated to sound in our brain. So, we could be here all day talking about material, shape, size etc. but that would be very limiting. That is why, if we include the 3 Octave Rule, things might not be as cumbersome.

Most drivers have a specific area or frequency band they like to operate in and this is very much related to surface are (or Sd as we like to call it ). The larger the area the less you can control outside its happy frequency range, typically its 3-4 octaves which is evident in the linear region. Once resonance, cone breakup, nodes and anti-nodes (areas out of phase irregularly distributed in the cone) the more noise it will produce, evident in the irregular and erratic behavior we see, evident in, typically, the higher frequency range of the driver, in the harmonic content and IMD.

To be fair, all drivers have an area of pistonic and linear region, the ideal is to have that for as long as possible. The other chapters of the perfect pistonic driver is down to how well the suspension and motor can control the cone motion. But I will say that in 2019, that is not so much of an issue.

I am not an engineer, so if some of the wording is off or I am missing to include a definition, please excuse me.

Link 1: The Truth About Pistonic Driver Cones | Vandersteen Audio
Link 2; UltraAudio.com Feature Article - Searching for the Extreme: Richard Vandersteen of Vandersteen Audio: Part One (9/2009)
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