[SPLGEO]

Tools you need:
-SPL meter (term lab)
-Load of building supplys( wood, screws, glue...)
- note pad a few of them
finding the frequency of the vehical( this will change depending upon the size and orenation of the box). To to this build a sealed box( aprox the size of the box you belive you will end up useing for the sub/s you will be using. Place in vechical and and a low volume, bass boost off sweep or if you have the time one hz by one hz. this will yeild the aprox, frequency. The frequency will vary with tempature.

Next use a a program( free of internet{winisd} or i use bass box 6 pro) to calculate the size of teh box and the port for the box. Keep in mind that some programs do not subtract port displacment, so you will have to do this manualy (LxWxD-baffle board). Most boxes will peak 5-10hz above what you tune it too, so amp the tuning alittle lower. As far as port area big is mostly better in this case. Also keep in mine that you do not want a port with alot of bends to it (smaller area less depth).

The way I have heard and will be useing this techneque from now on for my own personal boxes ios this...... make a reovable port, and a movable rear baffle board.
1. test at full volume the box with maxium port, max box size
2. move rear wall in 1/2" and re test
3. repet step 2. until rear wall cannot be move fuhter
4. keep track of teh frequency and the DB you hit
5. after the rear walll is move foward all of teh way remove port and trim 1/2" off teh port place back in.
6. repet steps 2-5 until you have found the max DB.
thsi process is mainly used for strong SPL subs( the RE MT, or FI BTL)

Notes.....
1. Baffles need to be thick, they are the weak point on a box
2. no internal bracing( causes to much internal turbulance)
3. if you are using Areo port make the external
4. Resin is your friend, and yes 45 degress do add some Dbs
5. the higher the frequency the better if an suz peakes at 34 hz it will aslo peak at 68 hz... 68hz will more then likey be louder


happy DB'n

[Gavin]

SPLGEO, on Feb 21 2007, 04:01 PM, said:

Tools you need:
-SPL meter (term lab)
-Load of building supplys( wood, screws, glue...)
- note pad a few of them
finding the frequency of the vehical( this will change depending upon the size and orenation of the box). To to this build a sealed box( aprox the size of the box you belive you will end up useing for the sub/s you will be using. Place in vechical and and a low volume, bass boost off sweep or if you have the time one hz by one hz. this will yeild the aprox, frequency. The frequency will vary with tempature.

Next use a a program( free of internet{winisd} or i use bass box 6 pro) to calculate the size of teh box and the port for the box. Keep in mind that some programs do not subtract port displacment, so you will have to do this manualy (LxWxD-baffle board). Most boxes will peak 5-10hz above what you tune it too, so amp the tuning alittle lower. As far as port area big is mostly better in this case. Also keep in mine that you do not want a port with alot of bends to it (smaller area less depth).

The way I have heard and will be useing this techneque from now on for my own personal boxes ios this...... make a reovable port, and a movable rear baffle board.
1. test at full volume the box with maxium port, max box size
2. move rear wall in 1/2" and re test
3. repet step 2. until rear wall cannot be move fuhter
4. keep track of teh frequency and the DB you hit
5. after the rear walll is move foward all of teh way remove port and trim 1/2" off teh port place back in.
6. repet steps 2-5 until you have found the max DB.
thsi process is mainly used for strong SPL subs( the RE MT, or FI BTL)

Notes.....
1. Baffles need to be thick, they are the weak point on a box
2. no internal bracing( causes to much internal turbulance)
3. if you are using Areo port make the external
4. Resin is your friend, and yes 45 degress do add some Dbs
5. the higher the frequency the better if an suz peakes at 34 hz it will aslo peak at 68 hz... 68hz will more then likey be louder
happy DB'n

Hey GEO, what's new? dude, you said something that I don't think is right.
test at full volume the box with maxium port, max box size <_<
full volume??? isn't that dangerious for the subs. Somebody who has never been down this road can loose a sub/subs very quickly! not knowing what the box is tuned at. trust me on that one.. I DID IT!! smoked 2 apx's in a new box, not knowing anything and start testing at 40Hz or was it 20Hz. hmmm, don't remember which one it was but I do remember the foul odor comming from my car! oh, and the white smoke. Speaking from experence, NEVER TEST AT FULL VOLUME AT FIRST!! start of low and work your way up. AND TAKE NOTES AS YOU GO!! as you go up in volume, you will notice that your peaks will change. (hence, the note taking!) also, give your subs time to cool down and your batteries a chance to recharge!.

Please, correct me if I'm wrong.

[kingsuv]

Hey you forgot the most important thing you need..... TIME

[BigOso]

I would also recommend a 2 clamp meters and a couple multimeters. You need to calculate your reactive load and the power from your amps for all aplications. Some deisngs might be louder and use more power. Others might be .1 off but use 500 less watts to achieve that score.

There are many diffrent ways to go about it but do not expect to accomplish all of this in a day or even a couple of days. Be prepared to spend many hours calculating, building and testing.

[Slinky]

awesome info geo!

[banginAltima]

SPLGEO, on Feb 21 2007, 05:01 PM, said:

5. the higher the frequency the better if an suz peakes at 34 hz it will aslo peak at 68 hz... 68hz will more then likey be louder
happy DB'n

can you explain this a little more, the part about peaking at 34 and 68?


Later

[Forevrbumpn]

what I used to do when I worked at the speaker shop, is when I would do in car testing with a sealed to find peak cabin resonance, I would test the box outside in open air, then inside car, both using the same sweep, and then find out what the peak resonance GAIN is over regular out door testing
when I was at the shop, out door testing was the best way to test boxes tower speakers, ect in Real worl envirnments
If the box had a peak gain at 40hz sealed, just like a 2db gain, but you notice in car gain is like 38hz 12db over that outside gain, the numbers seems to come together a little better-
basically you just learn a little more doing both in car, and out of car testing

[banginAltima]

i find this testing with a sealed box idea a little odd. based upon what i know about sealed boxes, the smaller the box the higher the frequency and the bigger the box the lower the frequency. so i don't see how this will find the cars true freq because that is subject to change with box size.


later

[BenH]

I'd like to add that minimal internal bracing could benefit in some situations. Threaded rod works great as bracing because it takes up mininal volume, causes little turbulence, and has a high tensile strength. It some situations it would be beneficial to add threaded rod if space requirements are too low for adding more layers to a box.

[Skip01]

Ahhhhh...the last 5 are not true

Number 3 and 5 particularly are wayyyyyyy off

[BenH]

Skip01, on Feb 28 2008, 06:02 PM, said:

Ahhhhh...the last 5 are not true

Number 3 and 5 particularly are wayyyyyyy off

I agree. Corners can hurt.

[psturmer]

the most important thing is to try new things.

[psturmer]

and those "notes" dont hold true in all cases

[Charger]

psturmer, on Feb 29 2008, 11:54 PM, said:

the most important thing is to try new things.

Very wise words! I feel the exact same way.

Nobody got very far from copying everybody else..

[Boon]

Charger, on Mar 3 2008, 02:00 PM, said:

Very wise words! I feel the exact same way.

Nobody got very far from copying everybody else..

In a way... copying known good can be a good way to get started in this game...

New Zealand record for Street B was done by replicating EXACTLY what they were doing in Europe and that score hasn't been touched for a couple of years - as soon as the box got changed, score dropped :<

[psturmer]

Boon, on Mar 14 2008, 02:33 AM, said:

In a way... copying known good can be a good way to get started in this game...

New Zealand record for Street B was done by replicating EXACTLY what they were doing in Europe and that score hasn't been touched for a couple of years - as soon as the box got changed, score dropped :<

it can be a good start. but i have gone through what people have told me works and most the time it actually hurts me.

[andym85]

imo...the best way to build a spl box, is buy a meter and test your ASS off!!!!

[Rip Rock]

Why do you want to make your back wall moveable in a wall?!? Add from the inside if you have to, it will make it stronger in the process, why make a leakly back wall? Most baffels like braceing from the baffel to the back wall, but not always, testing will prove that. We use round tubeing and weld a nut on one end and only, thread from one side, smoooth....... from the loading wall to the baffel. The only time I have seen resin work is in extreme and some ss builds, street i have never seen resin gain, but thats a different ball game all together. Resin is used basicly just used to seal up mdf because mdf is pouris (sp), it breathes.

[psturmer]

Rip Rock, on Mar 14 2008, 04:53 PM, said:

street i have never seen resin gain, but thats a different ball game all together. Resin is used basicly just used to seal up mdf because mdf is pouris (sp), it breathes.

just strait resin didnt do anything for me. but resin mixed with something and then applied it gained me .7 i believe.

[anubis]

what if i already know my vehicle's freq? go ahead and build my wall tuned to that freq?