Is there an optimum F3, port tuning frequency, for each specific cabinet size? For example 2 liter is 100 Hz, 3.5 liter is 85 Hz etc? Meaning you choose your F3 and then pick the appropriate size box?
For the Tang-Band W3-593SF Parts-Express recommends a 5.4 liter cabinet tuned to 75Hz. I have a 3.5 liter cabinet and a 7 liter cabinet. Do I want to tune the 3.5 cabinet lower F3 than it should or tune the 7 liter cabinet higher than it should? Another option is add some wood blocks inside the 7 liter to decrease the volume.
I do not understand why the W3-871S has a Vas of 1.66 liter and 0.29mH when the identical (except frame) W3-593SF has a Vas of 2.67 liters and .084mH?
Also I do not understand how this driver has a resonant frequency of 110 Hz but Parts-Express design it to 75Hz. Is not Fr the lowest a driver can go?
Perhaps there is some calculation or program for cabinet sized and F3 tuning frequency?
For the Tang-Band W3-593SF Parts-Express recommends a 5.4 liter cabinet tuned to 75Hz. I have a 3.5 liter cabinet and a 7 liter cabinet. Do I want to tune the 3.5 cabinet lower F3 than it should or tune the 7 liter cabinet higher than it should? Another option is add some wood blocks inside the 7 liter to decrease the volume.
I do not understand why the W3-871S has a Vas of 1.66 liter and 0.29mH when the identical (except frame) W3-593SF has a Vas of 2.67 liters and .084mH?
Also I do not understand how this driver has a resonant frequency of 110 Hz but Parts-Express design it to 75Hz. Is not Fr the lowest a driver can go?
Perhaps there is some calculation or program for cabinet sized and F3 tuning frequency?
Sealed has one degree of freedom, there are at least 2 on a relex, makes for a bunch of different compromises. What is optimal depends on what you are trying to do. It is WAY easier to screw up a relex than a sealed box.
dave
dave
They do seem similar in many ways.
For one thing, the latter has a softer suspension. After a quick glance at the other specs, they don't seem to bear this out so I'm still wondering myself. I also notice the motor force is a little less.
The higher compliance of the suspension makes it a little more sensitive to the box volume, meaning a larger box with it's softer restoring force can be used.
75 Hz is not a woofer
that is midrange driver.
Wouldn't want to hear it vented
regardless.
Sealed is what it is.
The bandwidth it does do.
Im sure it does rather well.
Wouldnt expect much bass.
What more that can be added to it.
Is any old basic "assisted" alignment.
AKA turning up the bass knob.
That does what it does, speaker is what it is.
Vas will be different with many drivers.
suspension will be so
stiff or so loose depending on the designers goal.
the Amount of force/air to reach that compliance
will be different.
that is midrange driver.
Wouldn't want to hear it vented
regardless.
Sealed is what it is.
The bandwidth it does do.
Im sure it does rather well.
Wouldnt expect much bass.
What more that can be added to it.
Is any old basic "assisted" alignment.
AKA turning up the bass knob.
That does what it does, speaker is what it is.
Vas will be different with many drivers.
suspension will be so
stiff or so loose depending on the designers goal.
the Amount of force/air to reach that compliance
will be different.
No. The cabinet, driver, and port are a resonant system. The driver's specifications heavily influence the scenario. Ported boxes typically start off with a specific alignment deemed optimal, but ultimately performance is on a continuum where you can adjust box volume and tuning frequency to achieve different levels of response peaking and roll-off rates at the expense of other performance aspects. Some drivers/boxes are more forgiving of alignment change or error than others. Simulation will help show how far you can push things and how these elements interact.
Tuning below the Fs of the driver is pretty common. It tends to cause a more gradual, extended roll-off at the expense of some output (due to what can be a very gradual roll-off starting significantly above the enclosure tuning frequency).
The free air resonance is where the driver naturally starts rolling off on its own, but it does produce output below that frequency and a driver/enclosure combination can have significant output below the free air resonance of the driver.
Unibox (by Kristian Ougaard) is another older Excel-based simulator for enclosures that is free. It's pretty easy to use.
Yes, I would like to see Parts Express simulation of the Tang Band W3-871s.
Mattstat, that some good information.
I asked Parts-Express how the Tang-Band W3-593SF can have the same 75Hz F3 as the W3-1878. The W3-593SF Xmax is .5mm and the W3-1878 X max is 4.2mm. He said F3 is based on their simulation software and Xmax does not affect frequency response.
The W3-593SF Qts is .58 and the W3-1878 Qts is .28.
Looks like while the lower Xmax will reduce volume and power (even though specs show the same 12 / 25W power rating) they both have the same F3. The different Qts also explains the sound quality. Nice when specs correlate to what I hear.
Looks like while the lower Xmax will reduce volume and power (even though specs show the same 12 / 25W power rating) they both have the same F3. The different Qts also explains the sound quality. Nice when specs correlate to what I hear.
Xmax itself is just a derived number that provides a quick and (very) rough guide to motor linearity / distortion performance. It is not directly connected to frequency response, or power rating either, as that is typically the thermal value of the coil. It has indirect links to both, but being a derivation, only as a consequence of other values. There are well over a dozen different ways of creating an Xmax figure, all of which will give different values if applied to the same drive unit, but the most popular is Gander's simple mechanical basis, which for overhung motor designs is
1-way Xmax = (|Coil winding height - coil gap height|)/2.
You can have the same F3 and very different alignments for a given enclosure Vb & Fb depending on driver Qt, Fs and Vas, which are the dominant factors in vented box design.
1-way Xmax = (|Coil winding height - coil gap height|)/2.
You can have the same F3 and very different alignments for a given enclosure Vb & Fb depending on driver Qt, Fs and Vas, which are the dominant factors in vented box design.
Tangband has numerous underhung drivers as well.
So underhung behaves somewhat different and stays within the gap.
So small xmax numbers can be misleading since people assume typical overhung behavior.
In a generic fashion xmax has not much to do with frequency response.
But a specific driver designed for less distortion within a certain bandwidth
such as a underhung midrange. Can have very small xmax numbers and then a very high Fs like 75 to 95 Hz.
Midrange on bandpass filter, excursion will be very low with no bass content
So underhung behaves somewhat different and stays within the gap.
So small xmax numbers can be misleading since people assume typical overhung behavior.
In a generic fashion xmax has not much to do with frequency response.
But a specific driver designed for less distortion within a certain bandwidth
such as a underhung midrange. Can have very small xmax numbers and then a very high Fs like 75 to 95 Hz.
Midrange on bandpass filter, excursion will be very low with no bass content
Simulation software is what you would want to look at. It's not just "one thing." It's a system. So several things influence this, the design of the cabinet included, etc.
There's online software like SpeakerBoxLite.com
And free software like WinISD, etc
Very best,
I am also thinking the W3-593SF's high Qts of .58 is also a factor in high Fs
Is that the driver you are talking about or the x-over to limit LF? I like to run full range with no eq if possible.
It isn't. Qts is a mathematical analogy to (Butterworth) electrical filter theory:
Qts = (Qes*Qms)/(Qes+Qms)
Where:
Qes = electrical damping factor at resonance
Qms = mechanical damping factor at resonance
Qts = summed electromechanical damping factor at resonance
Driver resonant frequency Fs:
Fs = 1 / (2Pi * (SQRT[Cms*Mms]))
Where:
Fs = Driver resonant frequency in Hz
Cms = suspension compliance in metres per newton
Mms = total mass of the moving components including the air load on the cone, strictly in Kg but usually given in g for convenience
Yes, Qes (electrical damping) is the single most significant variable
In your example, the Qes of the 871s is 0.71 and the Qes of the 593SF is 0.64
EBP =Fs/Qes
For the 871s 110/0.71 = 154.9
For the 593SF 110/0.64 = 171.9
In your example, the Qes of the 871s is 0.71 and the Qes of the 593SF is 0.64
EBP =Fs/Qes
For the 871s 110/0.71 = 154.9
For the 593SF 110/0.64 = 171.9
The downside to EBP however being it's fairly meaningless. There's a temptation for more to be read into it than ever was intended. It was only ever meant to be a time-saving indication, particularly prior to the widespread availability of computer / calculator based software. In the case of the above, both units are so far within its notional 'vented' category the unit difference between them is irrelevant -but without any other context / factors even that isn't much of a guideline.