Below I Haves shared Measurements of My Driver using DATS V3
FS comes out to be 86.3 and if can be clearly see a dip of graph which the software has analyzed as fs because of impedance peak.
but can be clearly seen it can play below 86.3 hz
so my question is how to calculate fs in such case as modeling software modeled graph will be only upto 86 hz
FS comes out to be 86.3 and if can be clearly see a dip of graph which the software has analyzed as fs because of impedance peak.
but can be clearly seen it can play below 86.3 hz
so my question is how to calculate fs in such case as modeling software modeled graph will be only upto 86 hz
Attachments
A speaker can play below Fs.
From Eminence.com (https://eminence.com/pages/support__understanding-loudspeaker-data)
From Eminence.com (https://eminence.com/pages/support__understanding-loudspeaker-data)
Fs
This parameter is the free-air resonant frequency of a speaker. Simply stated, it is the point at which the weight of the moving parts of the speaker becomes balanced with the force of the speaker suspension when in motion. If you've ever seen a piece of string start humming uncontrollably in the wind, you have seen the effect of reaching a resonant frequency. It is important to know this information so that you can prevent your enclosure from 'ringing'. With a loudspeaker, the mass of the moving parts, and the stiffness of the suspension (surround and spider) are the key elements that affect the resonant frequency. As a general rule of thumb, a lower Fs indicates a woofer that would be better for low-frequency reproduction than a woofer with a higher Fs. This is not always the case though, because other parameters affect the ultimate performance as well.
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Joined 2003
Fs looks like 86Hz, red line is phase..Impedance peak is Fs.
Not sure what the concern is here. Make sure T/S is measured free air, if motor is vented do not measure with motor on your desk, must be unobstructed.
Not sure what the concern is here. Make sure T/S is measured free air, if motor is vented do not measure with motor on your desk, must be unobstructed.
What do you mean by “but can be clearly seen it can play below 86.3 hz”? You mean you can see the cone move?
Also, a woofer in a closed box (for example) is much like a second order highpass filter in terms of the SPL response. You didn't post that so I can't comment on your exact driver, etc. but what happens at Fs and below depends on the value of the system Q. There is "output" below Fs but it is becoming less and less as you go lower in frequency. There is not an immediate cutoff in output. For example, here are a couple of values of Q and the associated response:
![figure1[1].png](https://www.diyaudio.com/community/attachments/figure1-1-png.1064493/ "figure1[1].png")
