SPL knowledge only……

[Burns]

If you don’t know what you are talking about please don’t make yourself look stupid. I don’t know the most about SPL but I have been messing around with it for a while. I feel that I have received bad advice. Me and the guy that helps me were talking to a guy that in my area was know for working in SPL. He told me a few tricks and I think I was screwed over. He was always saying that he should build me a box and I think he was trying to mess me up so I would get him to make me a new box.

I have been told to tub the inner corners of the box to be just like the inside of a tub. Thus making more SPL with the sound waves bouncing better. Is this correct????

I was told to cut down my box. I have pictures to show this but I think I cut over a cubit foot of air space on my box. I was also told to fire the port at the back hatch and he gave us a size to make the port. Originally the port was firing at the roof. We did as he told us because we thought he would not steer us wrong. I added one strand of high count 0 gauge wire. For power and ground. I also upgraded my input lines and I think I went down. I did have amp problems at the time and now have a better more reliable amp.

these are not the best subs for spl but i was still able to reach 146 with 4gauge wire and a weak batt.

before it took up all the way to the door. the lift gate handle made an impression in the box carpet.

Now i have moved to what advise i recived.

 

[Wagonized]

those are 4 12s correct?

how much power are you running to them?

my first suggestion would be to make the box much much smaller than it is now. try 1-1.25 cubic feet per sub. Sub up port back will probably be loudest.

If this is an spl only box try tuning to 44 hz to start then shorten your port slowly from there. Or even better get some aero ports which are much easier to shorten and reinstall than a conventional slot port.

If you do decide to go with a slot port I like to make mine around 50% of the total cone area of the woofers for SPL boxes and adjust the length according to your desired tuning freqnency. And if you decided to do a slot port I would place it at the very bottom of your box running the whole way horizontally across.

If you decided to go with aeroports id suggest 3 4 inch aeros or 2 6 inch aeros depending on availability and your budget.

Have you upgraded the big three wires under the hood?

The "tubs" you mentioned in the corners of the enclosure are commonly reffered to as "45s" because you're changing a 90 degree angle to a 45 trying direct the air in a smoother fasion. 45s can help or hurt you though. theres no set in stone answer. SPL is a tricky game and its very hard to play without your own personal mic to test at home whenever you want. Having your own mic is the ultimate advantage over the other competitors. Much more important that running good gear.

 

[Burns]

those are 4 12s correct?

how much power are you running to them?

my first suggestion would be to make the box much much smaller than it is now. try 1-1.25 cubic feet per sub. Sub up port back will probably be loudest.

If this is an spl only box try tuning to 44 hz to start then shorten your port slowly from there. Or even better get some aero ports which are much easier to shorten and reinstall than a conventional slot port.

If you do decide to go with a slot port I like to make mine around 50% of the total cone area of the woofers for SPL boxes and adjust the length according to your desired tuning freqnency. And if you decided to do a slot port I would place it at the very bottom of your box running the whole way horizontally across.

If you decided to go with aeroports id suggest 3 4 inch aeros or 2 6 inch aeros depending on availability and your budget.

Have you upgraded the big three wires under the hood?

The "tubs" you mentioned in the corners of the enclosure are commonly reffered to as "45s" because you're changing a 90 degree angle to a 45 trying direct the air in a smoother fasion. 45s can help or hurt you though. theres no set in stone answer. SPL is a tricky game and its very hard to play without your own personal mic to test at home whenever you want. Having your own mic is the ultimate advantage over the other competitors. Much more important that running good gear.

You are truely right it is a tricky game.

There is a term lab meter in the town right next to me. I used to use is when i needed it but now i dont have access to it anymore.

As for aeros I have looked at them and i dont think i am ready to try that.

I need to do the big three. I really have not touched that yet. Im swapping in a better motor soon and i plan to do it then. I have a lot of un done things that I could do to boost myself. I need to go and try to use the mic and see where I am standing at with the new amp.

They are 12" visonik 500rms 700max im running 3ohm. The amp is a HIFONICS BRUTUS BXI SERIES BXI1206D its is 1200max at 1ohm. gets lower from there. im not pushing a whole lot of power.

 

[bamaboy1234]

Wagonized pretty much summed up everything, none of the things anyone suggest to you is set in stone to make your score go up

maybe try fiberglassing the inside of your enclosure with resin

bracing with either wooden dowels 1.25", or 3/4" threaded rod

like said before 45's in the corner so you can try not to have any "dead spots"

ive seen sealing the enclosure up with ducktape bring in a decimal or 2

the best thing you can do for SPL is box and box placement, its just a matter of doing things and testing them

but there isnt much to work with on 1200 watts unless you make up for it with lots on cone area

 

[Wagonized]

Wagonized pretty much summed up everything, none of the things anyone suggest to you is set in stone to make your score go up

maybe try fiberglassing the inside of your enclosure with resin

bracing with either wooden dowels 1.25", or 3/4" threaded rod

like said before 45's in the corner so you can try not to have any "dead spots"

ive seen sealing the enclosure up with ducktape bring in a decimal or 2

the best thing you can do for SPL is box and box placement, its just a matter of doing things and testing them

but there isnt much to work with on 1200 watts unless you make up for it with lots on cone area

there are really a ton of things he could do. and if i made list of suggestions then i wouldnt have any secrets now would i?

duct tape around the subs works well 90% of the time.

bracing the box can help or hurt you. Usually a box that flexes will have less box rise...which obviously means more power

 

[Burns]

right now the top i think is to flexy lol

I have fiberglassed it in and out and i have cracked it between the closes two subs.. you can see it moving

 

[Wagonized]

right now the top i think is to flexy lol

I have fiberglassed it in and out and i have cracked it between the closes two subs.. you can see it moving

if you can physically see it moving then yes thats too much flex lol


all the more excuse to build a new box though. Try to compile a bunch of different ideas and put them into your new enclosure.

 

[Burns]

if you can physically see it moving then yes thats too much flex lol


all the more excuse to build a new box though. Try to compile a bunch of different ideas and put them into your new enclosure.

Thats what im gonna do... This box was the one in carpet and it was cut down to almost 1.5 cubit foot per sub. Im gonna up around 2 to 2.25 per sub.

Im plan on using 1 inch sides and bottom with a 3/4 inch top. Im going to use round bracing.

Yeah the design now does not allow for a brace to be were the box is flexing now because the port... oh well

 

[Wagonized]

Thats what im gonna do... This box was the one in carpet and it was cut down to almost 1.5 cubit foot per sub. Im gonna up around 2 to 2.25 per sub.

Im plan on using 1 inch sides and bottom with a 3/4 inch top. Im going to use round bracing.

Yeah the design now does not allow for a brace to be were the box is flexing now because the port... oh well

if this is for pure spl then i think 2-2.25 cubes is too big for each sub. maybe a pair of subs for that much airspace.

and if you're going to make the box thicker at any point i would do it on the top. a double baffle with the subs countersunk

 

[matt987]

If you don’t know what you are talking about please don’t make yourself look stupid. I don’t know the most about SPL but I have been messing around with it for a while. I feel that I have received bad advice. Me and the guy that helps me were talking to a guy that in my area was know for working in SPL. He told me a few tricks and I think I was screwed over. He was always saying that he should build me a box and I think he was trying to mess me up so I would get him to make me a new box.

I have been told to tub the inner corners of the box to be just like the inside of a tub. Thus making more SPL with the sound waves bouncing better. Is this correct????

I was told to cut down my box. I have pictures to show this but I think I cut over a cubit foot of air space on my box. I was also told to fire the port at the back hatch and he gave us a size to make the port. Originally the port was firing at the roof. We did as he told us because we thought he would not steer us wrong. I added one strand of high count 0 gauge wire. For power and ground. I also upgraded my input lines and I think I went down. I did have amp problems at the time and now have a better more reliable amp.

these are not the best subs for spl but i was still able to reach 146 with 4gauge wire and a weak batt.

before it took up all the way to the door. the lift gate handle made an impression in the box carpet.

Now i have moved to what advise i recived.

Well i must say this.. you definitely want the port to fire directly towards the rear hatch, he is also correct about the box construction. rounded edges will make for easier and smoother airflow =more spl. and you were right for installing larger wire for power and ground. spl may have gone down but that could be because of your alternator wire being stock? .((((example)))).. with car on.. if you have 12 volts at the battery running 4gauge wire you might be able to play music for 20 min
before battery is drained low enough so the alternator cant keep up.. and if u upgrade ground and power to 0guage.. and not alt. wire then it could only play for 10-15 min.. because more power is being draind faster and alt. definitely cant keep up then. now i think im just going off subject a little bit.. i tend to ramble on and on.. if you want me to tell you more about box size and sound frequency and how it affects spl then let me know.

but if you really want to find out very helpful information go to
http://www.diald.com/usaci/index.php
you dont need a screen name or anything. browse around the site a little and you will find more information than you may have ever wanted to know about car audio.

 

[bamaboy1234]

have you found your peak frequency? or do you know the resonant freq of your explorer?

build a small box like said above, maybe 1-1.25 per sub, tune it to as few hz below you resonant frequency and give it a good bit of port

maybe if you want you can run changeable ports and wap them out for a lower tuning, but that small of a box is going to be peaky

www.termpro.com site of termlab, go to audio forums and read up

 

[Wagonized]

my first gen peaked at 51 hz with a similarly sized box.

rounded edges definitely do not always increase spl.

and also rear firing port isnt always the loudest in explorers. but its definitely a good guideline to start with

 

[matt987]

most 4 door explorers resonant frequency is around 50-53hz... i am way below that, my system peaks at 46.6hz. and im still only hitting mid 148 and low 149's. if i were to build another box and tune it a little higher i could hit over 150 easily.

 

[matt987]

oh yeah, but my truck is a daily driver so its not just for competition, its more of a quality/comp setup...

 

[Wagonized]

most 4 door explorers resonant frequency is around 50-53hz... i am way below that, my system peaks at 46.6hz. and im still only hitting mid 148 and low 149's. if i were to build another box and tune it a little higher i could hit over 150 easily.

what mic is that on and where was it placed?

every explorer is different. most 2nd gen 4 doors actually peak at 47 or 48 hz so you're pretty close. Probably a bit lower because I'd imagine your box takes up a decent amount of volume.

A team mate of mine competed with a bmw x5 and peaked at 43 hz. Weird things happen sometimes.

 

[matt987]

it was metered by the term-lab mic, in the passengers kickpannel..
oh and a little hint that i find helps numbers by a couple .10's of a db... in explorers, if you adjust your front seats as far as you can foreward and tilt the back rest part of the seat as far foreward as you can (while sitting in the seat)you will be cramped up, but it has raised db's for me. it might help you as well, every vehicle is a little different.

 

[Wagonized]

it was metered by the term-lab mic, in the passengers kickpannel..
oh and a little hint that i find helps numbers by a couple .10's of a db... in explorers, if you adjust your front seats as far as you can foreward and tilt the back rest part of the seat as far foreward as you can (while sitting in the seat)you will be cramped up, but it has raised db's for me. it might help you as well, every vehicle is a little different.

yea blocking as much airflow to the sensor as possible works very well.

 

[matt987]

sounds weird i know, but it improves my scores. and thats all that matters

 

[Wagonized]

sounds weird i know, but it improves my scores. and thats all that matters

its because your body or the seat blocks the air and has a venturi affect. the air rushes around the object right at the mic with more acceleration.

im 6'3 300 lbs and when i would burp my vehicle in iasca i would sit in the passenger side with the seat all the way forward and cram my body as far forward as possible to block the air to the mic. 0.6 gain. Tried it with a guy what was around 5'10 160 lbs and it was a 0.3 gain with all variables the same.

 

[Burns]

its because your body or the seat blocks the air and has a venturi affect. the air rushes around the object right at the mic with more acceleration.

im 6'3 300 lbs and when i would burp my vehicle in iasca i would sit in the passenger side with the seat all the way forward and cram my body as far forward as possible to block the air to the mic. 0.6 gain. Tried it with a guy what was around 5'10 160 lbs and it was a 0.3 gain with all variables the same.

well i might have to try this..... i did go up by cramping my self on the drivers side but i never thought to get on the other side