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Discussion Starter #363
Lol. Does it cost money? I just searched for dts neural upmixer and found some download site. Must have been a pirated copy or something then... It wasn't an offical site anyways


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Man i just spent the last hour reading this post from page 1 as i only have just joined this forum mostly didnt understand all the technical graphs and such but its a very nice build
I have a similar build plan as yours with 3 amps 1 for fronts 1 for rears and 1 for sub woofer and plan to mount it all in the spare wheel well aswell :) yours is a very nice well planned out design look forward to seeing more of it !
 

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Discussion Starter #365
Ordered more crap from tme.eu

TME is a really good place to order from btw... ^^













Tomorrow I'll begin with fiberglassing the door enclosures and I'll also remove the sub - the enclosure will be rebuilt...


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Discussion Starter #366
I'm trying to calculate the vent length for the subwoofer correctly. It's actually quite hard to predict accurately. WinISD almost always predict to long ports. I wanted 33Hz Fb I got 26Hz last time I trusted WinISD. The vent will also be angled and flared both sides. Another issue is the apparent volume size, although the enclosure is 105lit, 7,7lit will be displaced by the driver itself and the tricky part, how much will be displaced by port? With the calculated length of 82cm it would displace 23lit. If the vent needs to be shorted, the apparent volume of the enclosure will go up and increase Fb even further. Stuffing also affect. From experience I'll simply decrease the length by 15% from what's calculated, we'll see how accurate it is after measuring it...

A good read about the subject here: vent tuning
 

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Discussion Starter #367
Update:

Began building the subwoofer. Little tricky getting the slot port smooth internally but I think I managed to get it right. There is very little space to work with in every direction. I only got 40cm till the enclosure hits the "roof" of the trunk towards the backseat and the sub is 38,5cm in diameter. I've rounded the outer part of the vent and I will do the same to inner part. The vent area is large (290cm²) so I'm not that worried about port noise.







 

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Discussion Starter #368
Some close-ups on the sub itself.













T/S Parameters after it has been used for a while:

Qts: 0.43
Qes: 0.46
Qms: 7.06
Vas: 46lit
Fs: 39Hz
Re: 1,02 ohm
Le: 1,52mH/1k
Mms: 335g
Sd: 815cm²
Pe: 1000w
Xmax: 30mm p-p
Xlim: 50mm p-p
 

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Discussion Starter #369
Almost done with the enclosure, I took a little break re-arranging in the garage and helped my mom with some gardening work lol. We had summer heat for the past two days ;)









Glued down wool on every surface inside the box. I also made a mess with a chalk gun, the damn tube broke and splattered chalk everywhere... sigh.

Even though I've braced the backside in four places I still feel a bit of resonance at full output. I might add another sheet of MDF to the back, I think 12mm additional depth will fit. I measured the box, without any stuffing the tuning lies around 36Hz, with a few sheets of lamb wool I got it down to 34Hz, I will add a little more behind driver I think so it might go down even further. My experience tells me that even putting it in the car will lower it by some amount so it should be fine.

No port noise, with over 500w input. So I didn't screw up there ;)
 

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Discussion Starter #372 (Edited)
Box is done at least...











I made 5 "pegs" to fasten a frame in front of the box to cover the port etc... I'll continue with doors first then come back to that later...

The sub sounds great. The Fb ended up at 34Hz and this created a 9dB peak around 40Hz, had to turn down the level 10dB initially because the whole car was shaking even at moderate volume lol.
 

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Discussion Starter #375
Did some quick measurements. I'll plug port next time so I can see the difference with the same enclosure with EQed response to the same FR... That will be a funny experiment ;)

This is with the old EQ for the sealed sub. Haven't tuned anything yet.





Almost 10dB gain at 30Hz.



Pretty low distortion, will be even lower with proper EQ.





Looks similar to what WinISD managed to predict actually.



Did a test tone audibility test with a few minutes in-between. The audible distortion levels are lower than you might expect in the lower frequencies. This is with test tones, so the music audibility threshold will be higher of course, but with music there will be a lot of IMD distortions as well. I really believe a low distortion sub sounds better, low frequency distortion IS audible.

 

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