I'm addicted... (TC or SI?)

[Buffalohed 10+ year member]

I asked some questions about the LMS 5400 on the TC forum and am even more confused now.

Someone said the 18" 5400 needs close to 100 inches of port area. He said less than that would make a ton of port noise and distortion and would be "crippling" the driver. I don't see how that is even possible, but TC website lists port area for the 18" as 37.5 inches. Obviously it is near impossible for me to get 100 inches of area in a box only 20 inches tall, that means it would need to be like 5.5" wide, and it would only go 10" front to back before needing to turn around. How can I find out how much port area would actually be needed, between 37 and 100 inches, so I can determine whether the **** thing will fit in my trunk or not?

 

[audioholic 5,000+ posts]

I asked some questions about the LMS 5400 on the TC forum and am even more confused now.
Someone said the 18" 5400 needs close to 100 inches of port area. He said less than that would make a ton of port noise and distortion and would be "crippling" the driver. I don't see how that is even possible, but TC website lists port area for the 18" as 37.5 inches. Obviously it is near impossible for me to get 100 inches of area in a box only 20 inches tall, that means it would need to be like 5.5" wide, and it would only go 10" front to back before needing to turn around. How can I find out how much port area would actually be needed, between 37 and 100 inches, so I can determine whether the **** thing will fit in my trunk or not?

Port area is a rough way to get an idea how much air the sub/system is gonna move. Lets put it this way, if I bought an 18" sub and the manufacturer only recommended 37 inches of port area, Id be extremely upset. My XXX 15's need about 50 inches for each, so 100 inches for a large displacement 18 sounds about right to me. *shrug*

If you can't fit the port for an 18" driver in your trunk, you can't fit a ported 18 in your trunk. Not sure what other answer you could expect. Certainly dont recommend cutting the port area in half or less.

The smaller the port given the same air displacement, the greater the air velocity inside the port. The greater the air velocity inside the port, the greater the port noise will be. Think of blowing thru a straw, you can hear the noise the air makes as its released and turbulates at the mouth of the straw. Now blow considerably faster... the noise is greater. Basically the same principle at work.

 

[DFW40 10+ year member]

Well I am totally and irretrievably addicted to bass now. I installed my first "real" substage a couple weeks ago and I'm loving it... but I want more and better.
So right now I have a 15" TC-3000k in 3.1 sealed on a Sundown @ 1.4ohms, forward firing in my trunk.

Next paycheck I am thinking about upgrading. A couple words about the TC3k first though. It has very good tonal clarity and hits great in the 30hz range. Has decent to good authority at 20hz, but could be a lot better. It sounds pretty good tone-wise but it is a bit sluggish and muddy on drums. It is loud (I think), but not loud enough. I have never been to a comp or heard SPL setups so I can't compare how loud it really is.

Anyway I'm looking for three things in this order: Better sound quality with emphasis on very sharp accuracy, speed and control for kickdrums and electronic music, more volume, and more powerful lows in the 20hz range!

So there are 3 setups I am considering but I am also taking suggestions of course (I have about 5.5 cubes max to work with), whichever I decide on I will be adding a Sundown to strap for +/- 3500 watts:

1 x 18" LMS-5400 in about 4.5 cubes ported tuned to 22-26hz

1 x 18" TC-5200 ported OR with passive radiator box (concerned about SQ???)

2 x 12" Mag D2 ported in about 4.2 cubes tuned to 25-30hz

I was also thinking about a 15" 06 XXX but I have heard some not so great things about them, heating up, breaking boxes, etc.

Regardless of which of these I choose I will also be getting another Sundown to strap for roughly 3500 watts.

I guess my question is, which of these will do you think will suit my needs the best? It is absolutely necessary for the upgrade to have great sound quality and faster response, but I also want it to be loud as shit.

Figured I would throw this out there a good 2 weeks or so before I buy anything, to give me time to think it over and all that. Sorry for typing so much... I'm long winded, can't help it.

Thanks guys.

What do you have your sub crossed over at and what slope? Also I did not read the whole post but how many watts rms are going to the sub?

 

[Buffalohed 10+ year member]

Port area is a rough way to get an idea how much air the sub/system is gonna move. Lets put it this way, if I bought an 18" sub and the manufacturer only recommended 37 inches of port area, Id be extremely upset. My XXX 15's need about 50 inches for each, so 100 inches for a large displacement 18 sounds about right to me. *shrug*If you can't fit the port for an 18" driver in your trunk, you can't fit a ported 18 in your trunk. Not sure what other answer you could expect. Certainly dont recommend cutting the port area in half or less.

That is exactly the answer I would expect. Clearly I wouldn't do something like that if it would effect the performance of the sub, I was simply confused because of the huge rift in recommendations. I might be able to fit it ported anyway, but I need to know what area to work with before I can determine that.

I did some calculations and unless I am mistaken, a 110sq inch port that is 23" long, which is what TC recommends for a 30hz tune, then that is only 1.46ft^3 of space. So if the gross box size was 6 cubes, I could have 4 net and 2 for port/displacement/bracing. Am I missing anything? Is that tuning length accurate?

HAVINGFUN: Sub is crossed at 80hz, I'm assuming 12db slope (HU xover) and it's now getting roughly 1700 rms, I rewired it to .5 ohms today on my Sundown.

 

[Buffalohed 10+ year member]

This is quoted directly from TC Forum. Just want to run it by you guys to confirm that it is accurate:

I don't have a figure for the Sd of the 18" handy.... but if we estimate 16.75" diameter cone ( my LMS 5400 18" are a few miles away at the time so I can't measure them ), then it has an Sd of about 220 square inches.
To have an optimum port, trying to shoot for about 1/2 of the active Sd, we are now talking about 110 square inches of port area.

So I should shoot for 110sq inches of port area, right?

 

[audioholic 5,000+ posts]

I just punched in the numbers real quick into WinISD. According to it, with a box volume of 4 cubes (net), and approx 100 sq inches of port area (I put in a 4x25" port), the port length would need to be over 65" long to achieve a tuning point of 30hz.

100 inches is ALOT of port area, and 30hz is low tuning point, both of which increase port length. So yeah, you're are gonna be needing a long port to accomplish your goal.

 

[SQBubble 10+ year member]

4.4cu.ft @30hz with 110sq.inch the port will need to be 73inch long, pretty ridiculous...lol.... just go with an 5400 15", OR, you could use the passive radiator

 

[audioholic 5,000+ posts]

Oh hey a PR is not a half bad idea. Good thinking SQBubble.

 

[HitManSE 10+ year member]

and it's now getting roughly 1700 rms, I rewired it to .5 ohms today on my Sundown.

The saz-1500 puts out about 1800rms @14v when wired to 1ohm. If you have it wired @ 0.5 you're getting a little over 1700rms. Not sure exactly how much (you'd need a bench test to tell you that), but its more then 1700.

Btw- not sure if this was mentioned before, but what vehicle is this going in?

 

[Buffalohed 10+ year member]

Alright, thanks for doing that guys. It looks like I will have to reconsider what I'm doing. I'm kind of pissed off right now that the TC website is so misleading. 3.5cube box with 37.5 port area and 23inches long. Not even ****ing close to what everyone is saying it is needing. Ridiculous. I'll have to look into PRs assuming I still even consider an LMS 5400.

This is going in a 96 camry.

 

[SQBubble 10+ year member]

Alright, thanks for doing that guys. It looks like I will have to reconsider what I'm doing. I'm kind of pissed off right now that the TC website is so misleading. 3.5cube box with 37.5 port area and 23inches long. Not even ****ing close to what everyone is saying it is needing. Ridiculous. I'll have to look into PRs assuming I still even consider an LMS 5400.
This is going in a 96 camry.

that kind of box would be tuned around 32hz...

37.5 sqinch of port area is for 12inches subs...

usually a 15" take around 40 to 70sq.inch

and an 18" should need from 70 to 130sq.inch

it really depends on the amount of air that a sub can produce and the size of the box

ppl say each cubic feet need 16sq.inch (quote from digital design)

but it varies

 

[jeremiah 10+ year member]

you have your sub in a sealed box try a ported box you will get about 6db

 

[Buffalohed 10+ year member]

I did some measuring in my trunk and as it turns out, I can fit somewhere in the area of 8-9 cubes if the sub fires upwards.

Messing with WinISD I could probably get away with a 30hz tune in a 9 gross cube box. I think. I have no idea if I even want to try that anymore, so we will see. It's pretty ridiculous how much the port length goes up when you try to tune lower. The difference between 30hz and 32hz is 6 inches... //content.invisioncic.com/y282845/emoticons/crap.gif.7f4dd41e3e9b23fbd170a1ee6f65cecc.gif

So the choice is either 15", 18" with PRs, or 2 Mags. The Mags are looking pretty appealing right now. Unless I am totally wrong on what kind of box 2 12s would require.

 

[HitManSE 10+ year member]

This is going in a 96 camry.

See thats the issue with running such a large setup, a truck car. I have the same issue //content.invisioncic.com/y282845/emoticons/laugh.gif.48439b2acf2cfca21620f01e7f77d1e4.gif

I have 2 15" mags awaiting an install, id love to put them in a ported 7.5-8.0 cube enclosure tuned to about 32hz, but thats not exactly possible to do. Im leaning more towards a 5 cubes sealed for both. Ill worry about that later.

The only issue is IF you can somehow get a box as large as you're thinking into your trunk, you dont really need to push it upto 9 cubes either.

7 cubes (after displacment) would more then be enough for 2 15s to get moving.

Dont worry so much about the port tuning between 30-32. You'll be fine either way IMO.

 

[Hundreth 10+ year member]

Your better off going a size down if your having trouble fitting a ported 18. Just do a ported 15, that way you can test the TC3k in that box before you decide to dump your money on the LMS.