rytek

I have a Kicker Solo Baric L7S15 and was told this about building a box.
"Enclosure will have to be 17"H x 24"W x 20"D, this will give us a gross box vol. of 3.82^3ft . Now if the sub will be appx. 50" from the dash, your tuning freq is 56.5Hz. so here are two port ideas for you, for max SPL we build the port 16"H x 4.5"W x 22.25"Long, port vol of 1.19, port area of 95sq inches. This will move a ton of air and sound good doing it! Now we can tune in down some, if we tune @45Hz, port will be 13"H x 4"W x 21"Long, port vol. of .77, port area of 63.6sq inches. This will tighten up the bass and still hit hard and loud. "

I was a little confuesed when I tried to draw this up due to the length of the port. It seems too deep to me. I used a port calulator on http://www.carstereo.com/help/Articles.cfm?id=31 and was given a much sorter port length. Can someone shed some light on what depth to to make the port?

DavidA

Could you make it a slot in an L-Shape to go around the back of the box to increase the length?

snap-on

i always build sealed boxes because i much perfer crisp base to boomy geto bass

Ganoid

seems to me 56hz is going to give you a really big mid-bass. Dropping it to 45hz works a little better if you don't listen to anything with real low bass in it. One thing to keep in mind when tuning an enclosure is that the speaker will unload below the tuning frequency and significantly drop in out put. There is also the very real chance of driver damage due to over excursion below the tuning frequency. One other little tid bit is that the computer simulations do a great job of getting you into the ball park but the actual physics of the environment greatly affect how the driver actually responds in relation to tuning. When I build an enclosure I usually start at around 35hz tuning and start trimming the port from there. A low dollar frequency generator will shed tons of light on enclosure tuning once you have a working enclosure to play with but it will also show you any weaknesses in driver or amplification.

Winisd is a pretty darn cool freeware program for tinkering with different enclosures and drivers. It will also allow you to calculate any multitude of port dimensions. Keep in mind that winisd has no provisions for predicting what a car will do to your responds (commonly referred to as transfer function)

For that kinda driver moving that much air I would opt for two 4" ports.
3.82cuft to 45hz is 2x4" ports 5.66" long <- Don't plan on any really low bass unless your car has a godlike transfer function.
3.82cuft to 56hz is 2x4" ports 2.61" long <-this one will probably sound like complete crap.
3.82cuft to 35hz is 2x4" ports 11.25" long <-this is where I would start, You can always make the ports shorter to raise tuning to your liking.


One of Kickers recommended sizes according to their web site is 3.0 cuft with a 2.5"x16.25" port 19.5" long. doing the backwards math this is equivalent to a port that will flow a tiny bit less than two 4" round ports and the tuning is about 37hz.

Kickers recommended "Street Bass" enclosure is 4.5cuft using 3"x16.25" port 14.75" long. Converting this to round ports reveals that its a 4.5cuft enclosure tuned to 36hz and could be done with 2x4" round ports at 8.3" long.

I think your 3.8cuft enclosure is probably going to work well but I would start the tuning at around 35hz and work my way up since all of the kicker recommended enclosures start in the same 35-37hz tuning range.


have a look at the kicker tech sheet for those drivers in PDF format.
L7 manual

rytek

Thanks for the detailed help. I was wondering, how would I go about testing the ports then trimming it? Should I not glue the port in so I can take it out and trim it? I ask because to do so, wouldn’t the box need to be incomplete (not glued) and sound different then the final product?

Ganoid

I would purchase quality ports that can be removed from the front.
Something like this



I drilled the flange where the dimples are so I could mount it with screws. I also just slipped the port together and used a good quality duct tape to secure it instead of gluing it. I run 1400 watts to a single TC Sounds 12" for my home theater and so far the ports are fine. They even look pretty nice when installed.




As far as trimming them goes you just need to have a keen ear and know what your music should sound like. Shortening a port raises the tuning freq and usually makes it sound a little better up to a point with average music but the downfall is that you lose the deep base extension. Its really just a trade off but I would start with one of the above listed boxes. If you have access to signal generator just start feeding the amp that drives the sub with it and you will learn a lot about low frequency extension and be amazed as well. You may find that most of your music stays above 40hz and a 40hz tuning freq would suit you best or you may find the opposite if you like synthesized bass. With my home theater I started with a tuning freq of like 21hz but after some experimentation I cut about 60% of my port length off. My sub still plays down to 27hz but it does a much better job reproducing the critical 30-50hz range. If I feed the parameters into a program it says my sub should be useless below 35hz but I can personally vouch for its affects much lower. When you start running sine waves through the system and your sub that was moving 2-3" comes to a stand still and your ports begin to move huge amounts of air that's your tuning freq for the enclosure.

ldivinag

make a sealed box instead...

problem solved with the port... lol........

Bumpin' Yota

ganoid is dead on the money!

:rolleyes:

That 'boomy' bass you are talking about has ABSOLUTELY NOTHING, to do with the box type! I can garuntee you I can build you a ported box that will sound better than 99.9% of all the sealed boxes out there custom built or not.


And only get 1/2 of the output you paid for...lol

rytek

Thanks for the help, I will start working on it this week.

AbramHart

Just because it is ported does not mean it is boomy and does not mean it is gheto. Some of the best SQ rides I have heard use ported enclosures. Some of the best home speakers use ported including Dynaudio, Focal, Pardigm. I have been building enclosures for over 15 years now and when it comes to SQ I have used both ported and sealed.