SA-8 V2 Enclosure Frequency - Strange performance or expected?

[racer_boy_x]

Hi All-

First time posting here, this is a rad place to find info. I know there is a lot of discussion about the SA-8 V2 but couldn't find much info related to my issue. The sub hits really hard on some songs but misses almost all other frequencies completely (a good majority of songs). I have played with the crossover frequency between 35-250 and it makes basically no difference. Is this to be expected or did I build the enclosure wayyyy off? I am a total nube so I appreciate any help that you guys can provide.

Build:

• 2013 Chevy Volt Hatchback
• Single SA-8 V2 D2 - Sundown Audio recommended box (attached)
• Rockford Fosgate PBR500X1 wired at 1 ohm (measured output was 540 according to factory papers that came with it)
• Amp gain tuned using multimeter approx 25VAC (50hz sine wave test sound)
• Power/grounds 4AWG / Sub 8 AWG (although all wires had the be reduced to fit the amp doh!)

The enclosure was built exactly to spec from the Sundown recommended enclosure except I added dual 3/4" MDF on the box face but ensured the volume was the same. The jpg is attached of the specs. No air leaks, lots of liquid nail, Titebond 3, hours and hours of sanding. Is this just what I am stuck with? Maybe the port length is way off? Anyway, thanks in advance.

[zayres29]

picture doesnt work but that sub should be in a .75 cube box net tuned to 35 hz

[racer_boy_x]

Hopefully I fixed the image now. I thoguht the box was tuned to 35hz but the volume seems larger than .75 cubic ft. The cut sheet was taken from their website. Too large perhaps? Thanks for the help.

[SnowDrifter]

What sort of frequencies does it miss?

[racer_boy_x]

I am guessing here but it only seems to hit fairly low frequencies, sub 45hz maybe. When it hits it will rattle your teeth. But it seems that 9 out of 10 hip hop songs I play it is barely noticeable that the sub is there. Maybe the SA-8 v2 was a poor choice for an all-around sub? If I hosed up the box spec I am not above building a new box but spent way too much time building this thing that works with 3 rap songs from 1998.

[Jessica]

using my best guess with the dimension you posted i get 27hz tuning.

is your port width 1.25?

let me run some better numbers i could be off

[SICKSPD]

so without doing all the math, because I'm lazy, can u tell me what your net volume is, your tuning frequency, and the port area per foot/port length?

[Jessica]

this is what i get using the dimensions you posted. Might be why you can kill lows so well. If someone sees something wrong in my number speak up.

[SICKSPD]

yeah what he said ^^ if its tuned to 27 hz then there would be a limited amount of music that would sound amazing. Plus its tuned quite a bit lower than recommended so that would also explain the lack of performance, you're also a slight bit above the recommended box volume but some have argued this is okay with the sa-8s

[racer_boy_x]

That makes sense to me. The port width is 1.25". I am a little surprised that Sundown posted the cut sheet and box dimensions when it is so far off for tuning. I should have just used several of the designs that were floating around this forum. I was wondering why nobody had built the exact box that Sundown was recommending.

In any case I will double check all the measurements and confirm total volume. I want to say thanks for everyone helping me out, what an awesome community. When I build the next box revision I will post an update. Now...only to find the time...