T/S Parameter questions
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Crazy Confused Unregistered guest | Can anyone, in layman's terms tell me what this says about a sub? Regarless of brand, it's a DVC 4ohm 12. What can I determine from the below information? -If the XMAX is 38MM peak to peak, whan can I assum the one way is? -Isn't 83db sensitivity pretty low? what will that affect? -With an Fs of 26.24, will this 12 hit reasonably low? -Is it true that subs w/ QTS of .50 or greater are best suited to sealed enclosures? T/S Parameters Fs . . . . . . . . . . . . . . . . 26.24 Hz Re . . . . . . .. . . . . . . . . . 8.13 Ohms (series) Qms . . . . . . . . . . . . . . . 8.40 Qes . . . . . . . . . . . . . . . . 0.67 Qts . . . . . . . . . . . . .. . . 0.62 Vas . . . . . . . . . . . . . . . . 47.27 liters Mms . . . . . . . . . . . . . . . . 246.86 grams Cms. . . . . . . . . . . . . . . . 149uM/Newton BL . . . . . . . . . . . . . . . . .22.15 Tesla-M SPL (2.83v) . . . . . . . . . . . . 83 dB Sd . . . . . . . . . . . . . . . . 475.3 sq cm Xmax (measured) . . . . . . . .. . .38mm p-p Vdd - Driver Displacement. . . . . 0.167ft3 |
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Bronze Member Username: TdisantoPost Number: 62 Registered: Sep-05 | http://www.the12volt.com/caraudio/theile.asp explanation of T/s. |
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Crazy Confused Unregistered guest | Okay um...thanks. Anyone elase want to "help" me understand. That link above doesn't tell me what's good and what's bad and is still not in "layman's" terms. I need to know if the specs I listed above are good? Best for Sealed/Ported, etc. |
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Platinum Member Username: GlasswolfWisteria, Lane USA Post Number: 10435 Registered: Dec-03 | -If the XMAX is 38MM peak to peak, whan can I assum the one way is? 19mm one-way, but since it doesn't specify DUMAX ratings, there's no guarantee that this is a linear measure of Xmax, so the accuracy is questionable, and mostly going to be based on the company's reputation. -Isn't 83db sensitivity pretty low? what will that affect? fairly low, but this could indicate a strong BL, which means while the sub needs more power for the same output, the SQ could be a lot better thanks to better motor control of the driver and better linearity as a result. Probably a sub targeted for SQ and not SPL. -With an Fs of 26.24, will this 12 hit reasonably low? very, in the right enclosure. I'd tune a ported box to about 28-34Hz with that sub, or go sealed. -Is it true that subs w/ QTS of .50 or greater are best suited to sealed enclosures? yes sir. the Qts is an indication of the motor's damping and rigidity of the driver's suspension. Specifically, Qts is the measure of a driver's tendancy to resonate at it's Fs. |
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Crazy Confused Unregistered guest | May the heavens bless you! Or thanks! Very helpful. |
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Bronze Member Username: TdisantoPost Number: 69 Registered: Sep-05 | I gave you the link because it tells you that Xmax is defined as linear one way travel. Linear means straight line Therefore 38mm is the one way "straight line" displacement, unless however, the company is saying its xmax but it's really referring to the total travel of the woofer. They would be incorrect in doing so. 83dB sensitivity is below average but that does not necessarily mean the sub you are talking about is inferior nor does it suggest that it wont be as loud as other subs with a higher sensitivity. It just means the sub is going to require more power to reach peak excursion (the xmax thingy). As far as the sub hitting reasonably low, you need to look at the frequency response of the sub. Since its a sub its gunna be able to play down to 20Hz and probably even lower (even though below 20Hz is in audible to the human ear) The type/size box that sub needs to go into depends on what the manufacture suggests. If your having trouble with this go to www.google.com and look it up. If you still cant find it start a new thread and maybe someone with the same/similar sub can tell you what type of box they used and what frequency they tuned it too (if ported). The reason i posted the link was so you could read up on what T/s specs mean. If you dont understand some of the words that they use, look those words up. www.google.com works well for this too. If you look, i posted a thread a week or two ago asking a link that defined T/s specs. So from then till now ive learned a lot. So if you read the terms you wouldnt need them to be put into laymans terms and you could have answered some of your own questions. I know this because i did it. |
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Gold Member Username: Basshead86Ocala, FL USA Post Number: 1295 Registered: Aug-05 | i have seen on some other posts that the idmax(i have a lot of ?'s about this sub lol) is best for sealed encloures, but it has a Qts of .35. doesnt that mean it is intended for ported enclosures, and it also has an Fs of 20.3hz and a sensitivity rating of 88db, so i can assume that this sub will hit very low? |
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Platinum Member Username: GlasswolfWisteria, Lane USA Post Number: 10445 Registered: Dec-03 | just as a technicality, when you see the term linear in reference to the excursion of a driver, they mean it's measured within the magnetic field's coil gap. ssome companies measure Xmax outside the gap, which is an inaccurate way to do it to boost numbers. Most subs don't operate very well, and suck tremendous power in order to work outside the coil gap, and the type of motor the driver uses has a large bearing on just how big the gap is, or how many gaps are used, how the driver functions outside of that gap if at all, etc.. that's why I defined the X specs using DUMAX linear measurements here; http://www.wickedcases.com/caraudio/thielesmall.html (bottom of page) a Qts if .35 can be due to a couple of things determined by other TS specs, like if you're talking about an overdamped motor, or a very rigid surround.. The IDMAX in particular has it's Qts as a function of it's unique motor topology, suiting it to small sealed enclosures and aperiodic enclosures which mimmick a large sealed enclosure by using a resistive membrane to impede the driver movement to tune the response of the sub, and mask 2nd and 3rd order harmonics. anyway long story short, while things like Qts are a good rule of thumb for figuring box types, there are always going to be exceptions that require a good understanding of all TS specs and how a driver works.. especially when you get into subs with specialty motor designs like the IDmax, RE XXX, and Adire Brahma that arre purpose designed for high excursion linearity and parabolic BL curves for ideal SQ at high output. |
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Gold Member Username: Basshead86Ocala, FL USA Post Number: 1300 Registered: Aug-05 | so would it wouldnt be ideal to put an IDMAX in 2.5-8 cu ft. box tuned to 28hz?(thats what they recommend for ported, and that is what i was going to do.) |
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Gold Member Username: Basshead86Ocala, FL USA Post Number: 1301 Registered: Aug-05 | i looked at this chart, and made what i could of it(which was a which is the highest line approach) and it shows that the ported enclosure is the most responsive.  © of Image Dynamics  |
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Platinum Member Username: GlasswolfWisteria, Lane USA Post Number: 10453 Registered: Dec-03 | yeah that's with cabin gain factored in.. ported shoould work fine. |
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Gold Member Username: Basshead86Ocala, FL USA Post Number: 1302 Registered: Aug-05 | hmmm...didn't move it up to the top of the thread list so bump! lol |
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Gold Member Username: Basshead86Ocala, FL USA Post Number: 1303 Registered: Aug-05 | oh ok GREAT!! sorry i didn't refesh the page in time. i have another ? in "does underpowering a sub hurt it" if you wouldn't mind looking at that one GW. your help is greatly appreciated. if we lived in the same state, i would buy you lunch. (i don't think shipping you lunch would work out very well. lol |
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