Printer Friendly Forum Posts

I am building a 6 cubic foot slot port enclosure to Kicker specs for an 08 L7 15 4 ohm (wired to 2). Did the Big 3 last year so I am getting a steady 14 volts to an 08zx750 to power it. The sub will take 750 in this enclosure. Will the amp be too much? It is certified @ 926 @ 14.4 volts. I have blown 2 12 L7's (older models) on seperate occasions. I assume due to port /enclosure size.

make sure it doesnt distort and your fine

gonna start w/ gain and bass boost all the way down on the amp and sub volume on head unit down -24 i think it goes to pioneer deh 4900 pioneer 6x9's,5 1/4's in the rear and 6 1/4's and tweets up front 08zx350.4 08zx750.1 back half of car completely dynamatted so far.

6 cu ft is a little big IMO for that sub.

-------------
Custom Enclosure Design

I had considered the 4.5 but it also drops the RMS om 1000 to 750 and I am already giving up my trunk for the sub. The 6 is the largest rec0mmended SPL enclosure for the 15 (Kicker recommended) I just thought the 6 will produce more low end deep bass. any suggestions will be taken with pleasure, as I said I have locked up 2 older L7 12's with this amp.(gain set to almost nothing)

I also would like to have the port rear firing w/ the sub. Will that be ok as long as I don't change the volume or size? The side firing will be too close the trunk interior I fear. The spec sheet calls for it to be behind the sub. @ 550 a pop I don't wanna blow this one.

Do 4.75 cu ft net tuned to 33Hz with around 65 sq in of port area. It will take 1000 watts all day.

I had a 15L7 in a 4.2 cu ft aperiodic bi-chamber enclosure and it took 900 watts rms all day no sweat. Heres it playing a 10Hz tone.

15L7 10 cycles ~500 watts

-------------
Custom Enclosure Design

Thanks Man, Now I can adjust the size too the 17 3/4 high was gonna be a bi*** to get in a 96 cav even removing the back seat

Before I die I hafta blow at least 1 decent woofer up..... I have never blown one, but it sounds fun. :/

depends on what ya pay for it and the time to build the box, wether it is fun or an expensive mistake.

I dunno wth I am doing!! 17.5 high will fit after removing the back seat so that leaves 16Hx4w for 65 sq inch port.@ 33 hz 26.75 Long?? That is 1.49 ft^ , So I figure to build an enclosure 3.26 ft^?? I am to add port volume , correct? If this is correct I will need to fold the port along the back ( a labyrinth port of sorts) I took 17.5 x5.5 x26.75/1728 to get port volume. Is that right?

OK I hope I got it right 27.625W x 17.5H x 15D port is 4Wx 16Hx 26.75 (33 hz for 4.75 ft^ enclosure) . The enclosure is 3.26 ft^ , port is 1.49 ft^, giving me a net 4.75. Well 5/1000 over, but I assume that is ok? Do I need gussets inside , and if so do I adjust to account for the volume they will take up? Sorry if I am being a pain, just wanna get it right the first time.

Net volume is after all displacements.

-------------
Custom Enclosure Design

I have actually made the 6cu.ft vented enclosure for the Kicker 07 L7 15. I powered it with the Hifonics Brutus BXI2005D. I have blown three of them (but not because of the amp). The 4th one stayed alive and well and is still kicking, pun intended. I only set the gain on the amp up 30% of its capabilities (roughly 600 RMS), and it was still amazing. You may have a problem if your amp is not capable of going any lower in power.

Just out of curiousity if the amp didn't blown the sub by overheating the voicecoil, how did the sub fail? Also, how did you limit the amp to 30% of it's output? I assume you're not talking about gain.

-------------
There is no such thing as free installation!

I was wondering the same thing myself. I took DYohn's advice last year and did the Big 3 upgrade. I don't think I wanna undo it. I want the power, just an enclosure that will allow the sub to handle that rms. I am thinking it will slam without the 6 ft^ it is going in a 96 cavalier back half of car completely dynamatted so far, powered by an 08zx750.1 according to my cap readout I am staying around 14 volts, but who knows how accurate that thing is.It was dropping into the low 10's b4 Big 3 upgrade, much cheaper than a HO alt.

Bigger the enclosure the lower the mechanical power handling...that is why you blew so many subwoofers.

The L7's are not high excursion subwoofers.

-------------
Custom Enclosure Design

tcss] wrote:

Just out of curiousity if the amp didn't blown the sub by overheating the voicecoil, how did the sub fail? Also, how did you limit the amp to 30% of it's output? I assume you're not talking about gain.

BOB!!!! Good to see you're still alive! Now, gimme a call! posted_image

-------------
It all reminds me of something that Molière once said to Guy de Maupassant at a café in Vienna: "That's nice. You should write it down."

[QUOTE=thatfloorguy] 17.5 high will fit after removing the back seat so that leaves 16Hx4w for 65 sq inch port.@ 33 hz 26.75 Long?? That is 1.49 ft^ , So I figure to build an enclosure 3.26 ft^?? I am to add port volume , correct? If this is correct I will need to fold the port along the back ( a labyrinth port of sorts) I took 17.5 x5.5 x26.75/1728 to get port volume. Am I doing this right?

net volume is the volume of air AFTER ALL DISPLACEMENTS.

You are not getting this right.

The port volume is not part of the volume of air the subwoofer "sees".

You enclosure will be bigger than 4.5 cu ft. That is 4.5 cu ft AFTER ALL DISPLACEMENTS.

-------------
Custom Enclosure Design

So i would figure the 4.75 you mentioned earlier, 65 sq inch port @ 33hz came to 26.75 long for that particulair volume, that was another 1.49. So the encloseure will be more like 6.25 including port ?

Will that design still handle 1000 watts RMS? That is gonna be huge if I am on track now. If not I am lost on this.

Yes the enclosure will handle 1000 watts easily.

The enclosure is going to be bigger than the Net volume because the port volume does not account for the usable air space. Same goes for bracing inside the enclosure.

Yes the enclosure is going to be big. We can make the port a little smaller if need be.

-------------
Custom Enclosure Design

So do I figure port length based on 4.75( which if i did that right comes to 1.49)add the 1.49 for the port , then use the volume calculator to get the dimensions for 6.24? 32.25Wx 17.5Hx 23.5D =6.26 that should account for my braces. The port 4x16 gives me 64 sq in @ 33 hz for 4.75 calls for just under 26.75. Am I on the right track yet?

The thing about accounting for port volume you MUST add .75" to the port width to account for the port wall.

I'll usually add .1 cu ft to account for driver displacement.

Yes you are on the right track right now.

See if this thread helps you laying out your enclosure.

Enclosure Design and rendering

-------------
Custom Enclosure Design

Thank you. I will re-read and begin to lay out the design after work. I was adding 1.5 inches when figuring the port, essentially counting the outer wall twice,that woulda screwed up my whole enclosure and possibly fried yet another sub. posted_image

OK I came up with 6.16 ft^3 internal (total volume) 31.5Wx17.5Hx22.25D, the port is 4x16x27.25. Do I figure port length by inside port wall dimensions? (hold 4 inches off back wall) first port wall is 18.25 then go flush off that cut (still holding 4 inches off back wall )and another 9 inch run?

aznboi3644 wrote:

Do 4.75 cu ft net tuned to 33Hz with around 65 sq in of port area. It will take 1000 watts all day.

I had a 15L7 in a 4.2 cu ft aperiodic bi-chamber enclosure and it took 900 watts rms all day no sweat. Heres it playing a 10Hz tone.

15L7 10 cycles ~500 watts

Just watched the video - sounds like an off-balance washing machine! I laughed when I heard it posted_image

-------------
VEHICLE: 2002 GMC Sonoma ZR2
Alpine CDA-7940
AudioControl EQT x2
JL Audio 1000/1
JL Audio 10W6 (originals) x3
Kicker ZR120
Kicker ZR460
Polk GXR-6 x4
Polk GXR-4 x2

that sound is just the mic on the camera...actually the only noise was air moving.

-------------
Custom Enclosure Design

I don't even think my amp is capable of going that low, I am pretty sure it is pushing at least 750 RMS tho. That is why I wanted the SPL enclosure that will still allow the sub to handle 1000. Thanx again for the invaluable info. That formula for the enclosures is great BTW. I must of just got lucky on my last one. I am still pushing 2 cvr 12's wired to a 2 ohm load in a fiberglass box i did, and just made a slot port centered abt. 3.5 wide by 14 deep. abt 4.25 ft^3+port. One has a voice coil going but it has been that way since last year. Most ppl can't tell but it bugs me I can hear it distort on certain songs.

Ok one more question. Is port placement a critical issue? All kicker specs show the port side firing. I want to have the port and sub both rear firing, that gives me around 18 inches clearence. The side firing port will be too close to the trunk interior. As long as i don't change the actual interior volume will I bo ok?

Ok so I am ready to build the enclosure. The sub is waiting patiently posted_image

Aznboi had advised me on a 4.75 ft3^ net w/port around 65 sq in tuned to 33 hz. To find port length I figure on the 4.75? Also on the thread for figuring internal volume do I add .4 for sub/internal bracing (08L7154) displacement? Can I make the port 64 sq in and still be safe? I only have 16 high internal volume to work with. Otherwise I need to make it 4 1/16 wide.(sigh). 4.75 for the enclosure 1.25 for the port and .4 for the displacement of sub and bracing for 6.4 gross volume. (next comes the sq setup for my other amp, 08zx750.4) any suggestions for around $2 to $250. I have read on here to only use 1 set of good speakers. I have 8 total speakers now and I am sure my amp is seeing like a 16 ohm load LOL

too much power?