Boxes. Tunings. Subsonic Filters. Oh my.

[zoltman1991]

Again, thank you all who have supported my journey thus far. I have narrowed down boxes into three options. I have questions regarding tuning of the box and how it plays a role with my LC2i's built-in filter (30hz).

I have:
-JD1000.1 pushing a Kicker CVX 15", with an LC2i.

These are the three boxes:
-https://www.ebay.com/itm/256501967064 (30hz)
-https://www.amazon.com/dp/B00NGOOCHE/?tag=caraudiocom-20 (37hz)
-http://www.qpowerinc.com/details.aspx?product_id=57 (37hz)

I keep reading about how the subsonic should be set half an octave lower then box frequency. The LC2i has response down to 30hz, which effectively acts as a filter (PLEASE CORRECT ME IF I'M WRONG).

Which of these boxes are most viable? I want longevity of system, protection of drivers, and quality. IF the box/LC2i aren't a good combo, is it worth ditching the LC2i and getting a subsonic filter or LC2i Pro, which has response of 20hz. So far, I am leaning towards the first option, which would match tuning frequency and subsonic filter.

Are these differences even worthy of consideration? THANK YOU!

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[Doxquzme Premium Member]

The LC2i is all you need for the subsonic (HP) filter, no worries there. It has a fixed Filter at 33 hz. Box recommends from Kicker:

Min Sealed Box Vol (cu. ft, L)
1.8, 51.0
Max Sealed Box Vol (cu. ft, L)
5.2, 147.0
Min Vented Box Vol (cu. ft, L)
3.0, 85.0
Max Vented Box Vol (cu. ft, L)
5.0, 142.0

In my opinion, you should be at least at 4.5 cu ft (min) for that 15" woofer. From

Kicker:

"All the cubic feet (L) measurements in this manual include the displacement of the woofer. For the vented enclosures the displacement of the port must be calculated and added to the internal volume of the final design."

That first box is listed at 3.5 cu ft. Take you driver displacement of (assumed .25 cu ft) and the vent displacement and you are looking at a box that has a net displacement of 3.25 cu ft, which comes in as the minimum from Kicker so it It will work.

That box from amazon is junk, it states it is 5.3 cu ft, it's not, it's only 4.2 gross and even though it will work at 37 hz, not very good quality and no way to ensure it is actually tuned at that frequency until measuring the port. It's work in a pinch,

The Qpower is the same size and tuned the same as the el-cheapo from Amazon, much better built and finished, will work but tuned pretty high at 37hz.

Of those three, the Qpower is the best option. the ebay one is next and the Amazon, while it will work, not confident in the build quality or the actual tuning stated after all they are way off on the specs for the volume. I've seen quite a few of these use 5/8" mdf on everything accept the front baffle assuming nobody will measure internally to see, not good.

If you can assemble your own, these are your best option. $294 inc shipping and tax. it's tuned to 31 hz and has a double front baffle.

15" single High Output XL Glue it & Screw It Sub Enclosure

GP Car Audio is a manufacturer of many USA Made ðºð¸ car audio products. We are also a distributor for several top Audio brands including Sundown Audio, XS Power, and Deaf Bonce.

gpcaraudio.com

 

[zoltman1991]

The LC2i is all you need for the subsonic (HP) filter, no worries there. It has a fixed Filter at 33 hz. Box recommends from Kicker:

Min Sealed Box Vol (cu. ft, L)
1.8, 51.0
Max Sealed Box Vol (cu. ft, L)
5.2, 147.0
Min Vented Box Vol (cu. ft, L)
3.0, 85.0
Max Vented Box Vol (cu. ft, L)
5.0, 142.0

In my opinion, you should be at least at 4.5 cu ft (min) for that 15" woofer. From

Kicker:

"All the cubic feet (L) measurements in this manual include the displacement of the woofer. For the vented enclosures the displacement of the port must be calculated and added to the internal volume of the final design."

That first box is listed at 3.5 cu ft. Take you driver displacement of (assumed .25 cu ft) and the vent displacement and you are looking at a box that has a net displacement of 3.25 cu ft, which comes in as the minimum from Kicker so it It will work.

That box from amazon is junk, it states it is 5.3 cu ft, it's not, it's only 4.2 gross and even though it will work at 37 hz, not very good quality and no way to ensure it is actually tuned at that frequency until measuring the port. It's work in a pinch,

The Qpower is the same size and tuned the same as the el-cheapo from Amazon, much better built and finished, will work but tuned pretty high at 37hz.

Of those three, the Qpower is the best option. the ebay one is next and the Amazon, while it will work, not confident in the build quality or the actual tuning stated after all they are way off on the specs for the volume. I've seen quite a few of these use 5/8" mdf on everything accept the front baffle assuming nobody will measure internally to see, not good.

If you can assemble your own, these are your best option. $294 inc shipping and tax. it's tuned to 31 hz and has a double front baffle.

15" single High Output XL Glue it & Screw It Sub Enclosure

GP Car Audio is a manufacturer of many USA Made ðºð¸ car audio products. We are also a distributor for several top Audio brands including Sundown Audio, XS Power, and Deaf Bonce.

gpcaraudio.com

Should my box be as close as the subsonic? Or should it be lower. I don't mind picking up the LC2i Pro to drop it to 20hz. For instance, the first box is at 30hz, while LC2i is at 33hz. Is it a problem that the box is lower than the LC2i?

Again, want to ensure I protect the speakers more than anything. I listen to a lot of electronic music with heavier, liquid bass. Wide ranges and long bass lines. Leaning towards the first option I sent (30hz) or even the one you sent. Assembling it doesn't look too bad. Won't be as pretty (I probably won't carpet it because I don't want it to look like crap).

But again again, I really don't mind getting the LC2i Pro (OR even the LC7i as I'm thinking of adding in a 4ch in the future perhaps.) - tbd. Just want to match my box freq with a compatible subsonic, or vice versa rather.

 

[Doxquzme Premium Member]

The LC2i starts it's 18 db 33hz roll off at 33hz so those two boxes that are tuned to 37 hz would be fine.

If you go lower in frequency, that tuning will require a bigger box as the port gets larger too, takes up displacement, etc. There is very little music program below 35 hz and dance music generally speaker-ing, pops at around 40-65hz, not much with anything lower.

You may need to be close to 5.5 cu ft for tuning a 15" down to the 23hz point (3db below that kikers 26 hz fs) as the port takes up over twice the area of those other boxes. A .8 cu ft in a5.5 cu ft box with a port of 3x14x42, the port alone takes up over 1.1 cu ft.

If you have the room, go for it. I would advise that the 35-37 hz tuning frequency for the electronic music you listened to is not better served by a lower tuned box.