T/S Parameter Sanity Check

Hey Guys! Upfront: I tried posting this on avforums, as i did another question before that, but since i am not getting an answer there, i thought i'll try it here. Seems a more suiting place anyway =)

Last Weekend is was finally able to put my DATS V3 to work. Unfortunately, the way to get there was rough, to say it nicely. After my diy-testbox was too big according to the DATS - 47liters, and not rethinking that error even after reducing the volume by almost 10liters, i threw the box in the garbage and did weight based Vas measurements. The two subs have both seen service in a dual ~30l (for each) sealed box in car-audio, were then put in the basement for quite some years, and were now pulled out to give them a new life.

Here are my measurements along with the manufacturer ones. It seems weird to me that they are that far apart from each other.

Since i want to built separate Enclosures for them,would a recommendation for one of those change in respect of the measurements?

Intended use is Home-Theater and Music at Home.
I am currently planing a vented enclosure, but i am also struggling with stuff like "WinISD gives me an 10x10 Port, while i want a slot port that fits the Enclosure size"

Thanks for your knowledge =)
 
You didn’t post the 2 sets of parameters.

The difference is to be expected. DATS collapses the T/S curves into scalars at a different point on the curves.

Fs and Qt will likely be higher for instance.

Here for example are my measures with kit similar to DATs, and the same driver measured by Mark Fenlon using factory kit. The factory numbers are given for reference.

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dave
 

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This is a comparison in WinISD of those two Subs. The difference is huge, since Sub_1 (in the pics with the parameters, this is the second row) WinISD suggests 65.25 liters at a Tuning frequency of 27.68, compared to suggesting 138liters with a Tuning Freq. of 23.74 for the second one.

Since i am trying to decide between those two for the first enclosure, that is not making it easier for sure XD
 
Since i am trying to decide between those two for the first enclosure, that is not making it easier for sure XD

Assuming your measurements are correct or still off 'enough' after more break-in/whatever, then average them to do a sim:

[33.11*31.19]^0.5 = ~32.14 Hz Fs, etc. and use damping, EQ or a mix of, to get the desired tonal balance since one will be slightly over damped and the other under damped in comparison, and if they should [still] sound a bit 'boomy' overall, then damp the vents and 'it is what it is' 😉: Click Test | GM210 | Flickr
 
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I am currently planing a vented enclosure, but i am also struggling with stuff like "WinISD gives me an 10x10 Port, while i want a slot port that fits the Enclosure size"

OK, 10^2 = 100, so divide it up to get the desired slot ratio, just keep it < 9:1 otherwise it may tend to have audible noise and/or 'choke up' at high power.
 
Thank you kindly for the answer,

unfortunatley i already did the plans and cut the wood, the port i calculated is 29x356m by now. Which is obviously not within your limits. i will round the ports out to minimize eventual chuffing, but we'll see what happens :/
 
Chuffing will in the end be a product of the air velocity, which should be kept under and as far away from 20 as you can muster. But do go on, post your plans. There's a lot of us here experienced in the physical side of building things (like me, a carpenter by study) that can do some creative thinking for you.
 
Air velocity is maxed at 23m/s, which was a value i found somewhere as a limit :/

i'll gladly post the plans, i upped the inner volume to 70 from 65 since i want to put some bracing from front to rear and left to right in it, plus the speaker, i hope that'll work out! There will also be a 12mm MDF Frontplate, which i will use to angle/round the inlets to the port (i subtracted that 12mm from the port wood-piece when cutting it)
 

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23m/s is going to cause chuffing, but it might be relatively minor if you don't regularly push it to the max.

Your slot port is a regular type that spans the whole width. This means that as long as you haven't glued it yet, you have a plethra of options to make either dimensions smaller or bigger. 🙂
 
Yeah, i haven't assembled the Enclosure yet! Although i am pretty much incapable of cutting straight lines with my skills/equipment here, and i wanted a simple to build design (hence the full width port), i am not good at using the usual electrical hand-guided saw XD

Although for the Port-Board that would not be much of an issue, but surely for all the ones which are connected on both sides XD