Optimal Sub Angle and Amp Size Options

[LastOfTheSTs]

Hey Guys,

I'm planning a 10" or 12" sub for the trunk just to round off my upgraded sound system - I was planning on probably making my own box for it and the amp but I was wondering, if there is indeed one, what is the best angle for the sub to be mounted at would be, i.e. straight up. straight back towards the end of the car, straight forward to the front or at a 45 degree angle... any thoughts?

Also does the box need to be any specific size in relation to the sub size beyond physically holding it?

Thanks for the advice

LST

This post has been edited by LastOfTheSTs: Aug 31, 2008 - 11:58 AM

[GriffGirl]

I bet this guy knows the answer to your questions!!! I'd ask him.

http://www.6gc.net/forums/index.php?showtopic=61467

[D-Man]

The size of the box needs to correspond with the requirements of the sub woofer. The angle in a hatch back will always be facing stright back, idealy with a 5-10degree angle upward as to reflect the waves ultimately to the crest of your back. G/L.

[DEATH]

The size of the box needs to correspond with the requirements of the sub woofer.

Very true - number one thing most people do wrong on their systems right there.

The angle in a hatch back will always be facing stright back, idealy with a 5-10degree angle upward as to reflect the waves ultimately to the crest of your back. G/L.

Not always true. That depends entirely on the size of the speaker, the frequency it's producing, The total output, the size and style of the enclosure [Ported/unported], the style of music the driver prefers and whether or not the seats will be down often.
For instance, I'd never point 10" sub in a ported box towards the front of the car - it just sounds like a baseball autopitcher at the batting cages
But for a 15" sub in a sealed box running approx 500 watts then yeah - facing towards the front is what I've found works best and I've had alot of 15"s facing every way you can imagine.
It's kinda all up to personal choice really.

[LastOfTheSTs]

OK so some things to think about here, thanks for the advice.

I also need to consider what size AMP - the front and rear speakers are powered by a Sony head unit (4x50watt) and I have no plans to amp these, so I don't want to overpower them with bass. I listen to rock music and I'm looking to acheive a good sound definition rather than sheer volume.

Suggestions on amp size / sub size?

Also does it matter if the sub is not central in the boot - I was thinking about placing towards one side so I can at still put one seat down easily.

Thanks for the help guys!

This post has been edited by LastOfTheSTs: Aug 31, 2008 - 3:59 PM

[AnaXyd]

45 degree angel is probably the best one. It will send the low frequencies against the rear window and it will reflect the frequences forward to the cupè. I have done this in my own Hatchback, and it sounds really good. I am using the Earthquake SWS 12, since it is 3" deep.

[RickJamesBish]

Good thread.

[Jaws4God]

i heard that subs are omni directional so it doesn't really matter which way they face..


I just set mine up for what I wanted it to look like.

[xredjokerx]

WOW jaws that is NICE custom work. i jsut have a HUGE rectangle box in mine HAHA rests against the strut bar but i cant even fit a basketbal in the trunk LOL

[LastOfTheSTs]

yeah it looks good (not sure about the stuff in the display cabinet).. more power than I'm looking at though, potentially the following combo:

Sub model: JBL: GT5-10 - 10" (JBL GT5-10" Guide)

Amp Model: BL: GTO-752e Amplifier

So from the advice here and my research I'm looking at the following for the sub enclosure for a 10" sub:

A ported enclosure sounds best sound against complexity of build. For my combo I will need 35.4 liters.
Different shape sides to prevent resonance issues
Have the Sub pointing towards the rear of the car with a slight angle upwards

Any other tips - also any thoughts on the my Amp/Sub choice, will this be enough for my needs?

[D-Man]

...I also need to consider what size AMP...
...I listen to rock music and I'm looking to acheive a good sound definition rather than sheer volume...

Sub model: JBL: GT5-10 - 10" (JBL GT5-10" Guide)
So from the advice here and my research I'm looking at the following for the sub enclosure for a 10" sub:

A ported enclosure sounds best sound against complexity of build. For my combo I will need 35.4 liters.
Different shape sides to prevent resonance issues
Have the Sub pointing towards the rear of the car with a slight angle upwards

Any other tips - also any thoughts on the my Amp/Sub choice, will this be enough for my needs?

This sub that you have shown will require a 300W amp, with the gain turned about 90% of the way. Port your box, map the sound waves with strings and cones. Death was correct in the fact that alot of what you do is dependent on the size of amp, however for a 10-12, What i've said will be premium. (He's got a 15, so his turning is different than what your's is going to be.) (infact, i've got 2 high power 12's, I have to tune different than most )

Building a box, Remember to use Medium Density Fiberboard (mdf) and you'll want it about 3/4 inch. For this sub your box will need to be 1.25 ft.³ (cubed) with a 3" x 8 5/8" port in it.

Also; DO NOT use silicone sealant in between the boards of the box. It will provide cushion and not "hit" like it's supposed to. Use wood glue or something HARD. Afterward, you can use the silicone to make sure that all edges are air tight.

This is all very technical; but it will sound fine if you should be off a .00213 inch J/k! Seriously though, if you're off a little bit, it wont make much of a difference; just do your best and take lots of pictures. Good luck.

[LastOfTheSTs]

map the sound waves with strings and cones

Now we are getting technical - can you explain this a little more for me?

Thanks

[D-Man]

oh, okay.

First, Please note that this is probably going to spark a HUGE controversy in witch everyone is going to lay down the law about how wrong i am. Just like my version of testing the quality of metal, or D/S rotors, or spoilers... and the list goes on... Funny how my sh!t works pretty damn well though I'm old-school white trash sometimes, but effective is effective Again, this is not exact science, but when i fiberglass boxes, i use this method to ensure that what i've built isn't total garbage after all the work & effort i put into my work

Okay, You'll wanna grab the cone that you change your oil with or something. (roll a sheet of paper or anything to make a cone) And place it on your woofer's face pointing out. Then you'll want a small ball of yarn and some of that Ticky-Tack that your teachers never let you play with in school. (you're also going to need a protractor and a small flashlight, Maybe some tape if you cant come up with ticky tack, i just like playing with that stuff .)

The object of this game is to figure out where the highest concentration of sound waves will be going. So, take your cone, and place it infront of your woofers face pointing so that it's male. Shine your flash light thru the female side and see where the light lands. Now ticky or tape the yarn from the cone to the light. Now invert that drgreese and keep going by adjusting the woofer, you'll see where the center of the wave lands and how dramaticaly it adjusts when you change the subs just a little.

Now again, this is not exact science, but it's damn good science. lol. Smaller woofers can reflect the sound to better fill the car, and while this isn't a perfect replica of what the sound waves are doing, it measures the center of the wave theoreticaly accurate. In real life a sub fires in all directions, but the front 180deg. has the most volume. We're just maping the center of this "big Part".

Again, not perfect, but damn good. (or you can go blow your money on a decible meter and hold it to the back of your seat with the stereo blairing, while a buddy adjusts and adjust and adjust (ect) untill you get the highest reading. That's the "profesional" way of doing it.) Retarted if you ask me... But w/e

Good luck, and may the flaming of my methods begin

[LastOfTheSTs]

Hey well D-Man no flaming of your methods to date so i guess they aren't all that crazy huh!


Anyways i've planned the basic sub enclosure design - this gives me around 35 cubic litres according to my calculations (about .4 off the optimum 35.4 for the sub). As you can see with this i've followed the example of most pre-bought boxes and have the sub pointing straight back towards the rear of the car.



I don't have the sub yet so using the cone and string method is tricky - will this design make it sound awful? It seems to be how most people fit them..

This post has been edited by LastOfTheSTs: Sep 8, 2008 - 3:17 PM

[D-Man]

I'm not whipping out my calculator... But everything seems to be in order... You've done your research i see. You ensured that your port tube goes farther back than the subwoofer so that it focuses your port-blast. Good man.

Also, using that fibery crap you find in pellows, you can get a 5% - 20% boost in nonexistant aero space. This is used when a box cannot fit where it needs to go, and size is reduced for fiture... it helps make a smaller box sound like it is bigger. (another trick of the trade, and not the proper way of doing it i'm sure, but i'm all about effectiveness. )

You can buy that stuff at the walmart fabric section. I think it's called stuffing or something... IDK.

Dont forget our pics now

[LastOfTheSTs]

Thanks D, JBL make it pretty easy on their website as they have a technical sheet for the enclosure requirements but I as you say I like to research too.

thanks for the help, i'll post pics as I build it all up.

This post has been edited by LastOfTheSTs: Sep 8, 2008 - 4:19 PM

[RickJamesBish]

Holy **** D-Man, that sounds so hard and annoying to do.

If I ever throw in a sub, I think I might just get it professionally done...

[itssteve]

its not hard to get box done and to make it sound loud and be optimal it may take a little trial and error but its not to bad, one option that has worked really well for me is sub up and port back, this is a crx style box and works well in suvs and hatch style cars, or you could try the sub and port back and just try and angle it, and the only other way i have tried that worked well was sub agenst the back of the car with sub and port facing twards the front