4th order bandpass

[rbgnwa45]

Anyone have experience? I have a RE XXX 12 that I can recone to an 18" and a 1500W amp that I might be able to get fixed. I'd like to try a cheapo (plywood, just throwing the box on the back of the back seat) 4th order wall with some aero ports for music, in my Olds Alero 4-door. I have two options for frequency response:

vented 5.884 NET
sealed 8.156 NET
s factor .7
passband (-3dB) 27.5-62.92 Hz
+6.78 dB @ 41.6 Hz

vented 4.323 NET
sealed 9.434 NET
s factor .6
passband (-3dB) 23-69.99 Hz
-0.83 dB @ 40.12 Hz

Would the first one be too peaky on music? The cabin gain would be wild at ~40 Hz, and still only -3dB @ 27.5 Hz is really good. Would it be able to be smoothed out with an EQ or something?

[Kickstarts-suck]

Ive never built a 4th order so I cant help you with that but I do have 2 things to say.

Don't use plywood. Use MDF or some good Birch($$$$)
Putting a box in the seats is dangerous. If you have to slam on brakes or get into a wreck your box could go flying into the back of your head.

I would say get on a car audio website and post in the "enclosure" threads asking for help for the box experts.

[rbgnwa45]

No, the box won't move because it's touching the front seats, it's squared off, even if it were to move upwards, it would hit the ceiling, it's too big to hit me if I stop fast. If it's heavy enough to rip off the seat hinges and then crush me into the windshield than that's what would happen. My last box came out of the trunk when I stopped fast, so I secured that. The most I'd secure it with is straps, nothing fabricated.

I did post in car audio forums. Nobody knows how to make a 4th order for that sub.

[slightlybent47]

You can use plywood but you need to brace it real good.
All large PA loud speakers use plywood because of weight concerns but are cross braced very well.
Don’t forget to re calculate for the mass of the braces so the cubic mass stays at the rite amount.
One thing I learned from experience is always build the box just a little bit larger then it needs to be. That way it will give you a little room for tuning the box.

[Scro]

Did you try termpro.com? Lots of people that can tell you how to build a 4th order and more.

[rbgnwa45]

I should mention that I'd never build a speaker box out of plywood - the plywood was to fab a wall, and then I'd duct tape it, and put a peice of leather over the plywood and just hope it doesn't flex much. It's pretty lazy, but I'm not going to build a false floor ETC, it's too much work.

Termpro has lots of 4th order stuff, I've read it all.

[YFZ-FoFiddy-TC]

I had 4 15's in a 4th and LOVED it. For that sub I would go with a 2 to 1 ratio. However I don't think you realize how much space a 4th order would actually needto sound good. You barely have enough room to do 1 18" ported. Secondly, if you're saying you want to use Plywood, I highly doubt you should even be trying a 4th order. Sorry to be blunt, but you don't just slap this stuff together and have it sound good. The only way you're going to have enough room is if you wall off the back. But whatever you choose, goodluck. And as Kickstart said, Birch or MDF would be best. Birch being best.

[YFZ-FoFiddy-TC]

Duct tape on a box...... Lol. I'm out of this one.

[rbgnwa45]

I have 9.25 cubes NET (that's after port!) in the trunk for ported @ 32.8 Hz with 14" of port area per cube. :devil:


The only way you're going to have enough room is if you wall off the back


just throwing the box on the back of the back seat) 4th order wall

You mean like a WALL that I mentioned in the first post? You realize the 4th order is ~14 cubes NET, right? That's exactly what one calls for :huh, 4 sealed and 8 ported.

Yeah, duct tape. I just threw that out there to tell you how cheap this'll be - I probably won't need it. I didn't actually say duct tape "on a box". Why would one put duct tape on a box?

The wall would be plywood and be covered by leather. I'm not sure how to secure it to the box, the front seats will probably keep it in place, and there'll be towels behind it so that it doesn't move back, so the thing is secure.

I know a lot about audio and walls, just not 4th orders. If you didn't notice, what I gave was a 2:1 ratio. I don't think you even read my first post :p.

There's no way I should be doing a 4th order - why? Because I ask about it? :ermm: Reeeall helpfull.

[ZBlaster]

Originally posted by YFZ-FoFiddy-TC
Duct tape on a box...... Lol. I'm out of this one.


LOL I've used Gorilla Tape to repair the surround and do another BassRace run before. It's not uncommon to see a good bit of it used on Extreme vehicles. Look at some pics from Slamology from this weekend and you'll be surprised.


OP: If you have to ask for advice you aren't ready for the 4th order. If you plan on using plywood I'm not even going to waste my time designing you one. By the time you added enough bracing/baffles to handle it you could be cutting down airspace tremendously. MDF is $28.30 at Home Depot here, if you spent the money on a XXX, something worthy of powering it (Hoping you aren't going to use something cheap on that sub), and want to do it right why would you waste the time?

I've built a few 4th orders, but if someone isn't willing to spend the extra cash on good materials why would they go the distance to make it work? A properly done standard vented box will preform tremendously better than a half *** bandpass setup.


If you decide you actually want to do it you can message me, OR hit up Mike Singer from Singer Alternators, or I can point you in the direction of a few others who will design you one up down to a cut sheet... but it won't be for free.

[ZBlaster]

Originally posted by rbgnwa45
I have 9.25 cubes NET (that's after port!) in the trunk for ported @ 32.8 Hz with 14" of port area per cube. :devil:






You should be doing 15-16" per cube for that sub to perform optimally. Also almost 10 cubes is on the big side for 1 12". 2.5-3.5 would work a little better I'd imagine. That's with enough power.

My advice for you with 1500 watts (given its true, clean power) is 4 ft^3 net tune it around 30hz with 15-16in^2 per cube, do sub forward, port forward, mount it behind the rear seat facing the front of the car(If your rear seat folds, if not remove the rear seat since your planning on making it useless anyway) seal it off COMPLETELY from the trunk so the port is firing into the cabin, and no air passes between the cabin and trunk area. This will net you the best performance on a meter and let you get what you want out of that sub.

[rbgnwa45]

Originally posted by ZBlaster
OP: If you have to ask for advice you aren't ready for the 4th order.

I've considered that, but why can't I just make one to the spec of a calculator? I've asked lots of experts, specifically the resident 4th order master of SteveMeadeDesigns. Why does everyone say that "if you aren't this than you aren't that"? Is a calculator really going to be that much off that I won't be happy with the result? I have two options, -1dB @ 40 Hz or +7dB @ 42 Hz, the -1dB has better extension by 5-10 Hz. My mom doesn't know how to turn a stereo on, does that mean she isn't ready for an aftermarket deck?


If you plan on using plywood I'm not even going to waste my time designing you one.

One what? I can design ported boxes in under a minute (with an end correction), and I can use 4th order calculators and google sketch up. I don't need a box design - just opinions on frequency response for music. The two options were optimal at Q .6 & .7 responses.


By the time you added enough bracing/baffles to handle it
you could be cutting down airspace tremendously.

1.5" baffle with .75" everywhere else isn't enough? Each portion would be about 40 x 22 x 15, it shouldn't flex. I don't bother with 45 degree wood in the corners, I'd use bent plastic, it's a better curve for smoother flow.




My last box was 1" MDF. The XXX was $350.


something worthy of powering it (Hoping you aren't going to use something cheap on that sub)

Visonik V900XD, 2 runs of 1/0.


and want to do it right why would you waste the time?

... or money for that matter.


I've built a few 4th orders, but if someone isn't willing to spend the extra cash on good materials why would they go the distance to make it work? A properly done standard vented box will preform tremendously better than a half *** bandpass setup.

Sooo what's the difference between a "half ***" bandpass setup with a flimsy wall and just having no wall with the box on the back seat? :huh The wall isn't going to make or break it! How does that make a half assed setup when either will work well?

If you decide you actually want to do it you can message me, OR hit up Mike Singer from Singer Alternators, or I can point you in the direction of a few others who will design you one up down to a cut sheet... but it won't be for free.

I don't need Singers' advicde, I've seen his LMS setups and they're wild. Last time I checked, he was using 2 ported 18" LMS Ultras with like 4 Sundown 3000's. I can design the box myself, but I cannot listen to what I do not have, I don't know if +7dB @ 42 Hz would be peaky, and that's what I really wanted to know, also if the 4th order calculators work well for predicted results. Pay for a cut sheet - I'm a lot more able than that, I can use google sketch up.


Also almost 10 cubes is on the big side for 1 12". 2.5-3.5 would work a little better I'd imagine.

In my first post, my second sentence was "I have a RE XXX 12 that I can recone to an 18." A 12" in a small box on the back seat would just look weird, like I might as well put it in the trunk.

It's not exactly true & clean power, but I'm hoping that the amp will put out 1000W after rise, and be fed with a steady voltage. I'm using a stock 105A alt with 1 aftermarket battery, dedicated to the amp if I can wire it up like that, with the one under the hood supplying the engine ETC. Try finding a large Alero alt, they're nowhere.

4 cubes for a ported 12" is double the size it needs to be :ermm:, and the 9.25 NET @ 32.8 Hz was for a ported 18" - which would be port & sub firing into the cabin and sealed off from the rest of the trunk, like I said I know all about ported boxes and how to get the most out of them. I can also fit 2 15's in 8.75 NET @ 34.8 Hz, and that's what I really want (with 3 batts & h. output alternator), but I figured I might as well use what I've already got. I'll still have to spend ~$300 to get the sub & amp fixed. A tinsel is fried and the amp fried a little, I'll be getting a fixmyspeaker.com recone, and I'll send the amp to S & S Electronics in Ontario.

I was wasting my time with a ported 12" in a horribly designed ported box (2.2 NET @ 36 Hz). It was fun but it wasn't bass-head fun. It was the loudest setup anyone in my small town has ever heard, so I atleast had some bragging rights :scary:.

[ZBlaster]

Originally posted by rbgnwa45
I've considered that, but why can't I just make one to the spec of a calculator? I've asked lots of experts, specifically the resident 4th order master of SteveMeadeDesigns. Why does everyone say that "if you aren't this than you aren't that"? Is a calculator really going to be that much off that I won't be happy with the result? I have two options, -1dB @ 40 Hz or +7dB @ 42 Hz, the -1dB has better extension by 5-10 Hz. My mom doesn't know how to turn a stereo on, does that mean she isn't ready for an aftermarket deck?



One what? I can design ported boxes in under a minute (with an end correction), and I can use 4th order calculators and google sketch up. I don't need a box design - just opinions on frequency response for music. The two options were optimal at Q .6 & .7 responses.



1.5" baffle with .75" everywhere else isn't enough? Each portion would be about 40 x 22 x 15, it shouldn't flex. I don't bother with 45 degree wood in the corners, I'd use bent plastic, it's a better curve for smoother flow.




I don't need Singers' advicde, I've seen his LMS setups and they're wild. Last time I checked, he was using 2 ported 18" LMS Ultras with like 4 Sundown 3000's. I can design the box myself, but I cannot listen to what I do not have, I don't know if +7dB @ 42 Hz would be peaky, and that's what I really wanted to know, also if the 4th order calculators work well for predicted results. Pay for a cut sheet - I'm a lot more able than that, I can use google sketch up.



In my first post, my second sentence was "I have a RE XXX 12 that I can recone to an 18." A 12" in a small box on the back seat would just look weird, like I might as well put it in the trunk.

It's not exactly true & clean power, but I'm hoping that the amp will put out 1000W after rise, and be fed with a steady voltage. I'm using a stock 105A alt with 1 aftermarket battery, dedicated to the amp if I can wire it up like that, with the one under the hood supplying the engine ETC. Try finding a large Alero alt, they're nowhere.

4 cubes for a ported 12" is double the size it needs to be :ermm:, and the 9.25 NET @ 32.8 Hz was for a ported 18" - which would be port & sub firing into the cabin and sealed off from the rest of the trunk, like I said I know all about ported boxes and how to get the most out of them. I can also fit 2 15's in 8.75 NET @ 34.8 Hz, and that's what I really want (with 3 batts & h. output alternator), but I figured I might as well use what I've already got. I'll still have to spend ~$300 to get the sub & amp fixed. A tinsel is fried and the amp fried a little, I'll be getting a fixmyspeaker.com recone, and I'll send the amp to S & S Electronics in Ontario.

I was wasting my time with a ported 12" in a horribly designed ported box (2.2 NET @ 36 Hz). It was fun but it wasn't bass-head fun. It was the loudest setup anyone in my small town has ever heard, so I atleast had some bragging rights :scary:. [/B]

The XXX 12's like around 2-2.5 WITH plenty of power, if your down on power you'll appreciate the extra airspace I mentioned. Anyone will tell you RE's specs for that sub are BS. In fact the new ones actually prefer a massive sealed box to perform at their bests.

There is no good calculator to predict a 4th order, it's mostly trial and error. Lots of experimenting with loading walls and port sizes to get the sound you want in your vehicle. A double baffle and then standard sides would NOT be sufficient if your using plywood. It flexes WAYY too much to not do internal bracing.

I wasn't talking about designing you a standard box, any idiot can do that. I do custom enclosures, I've built 10-12 4th orders over the past few years all with excellent results, and have designed up a few more.

I also never suggested setting it in the back seat, I said to remove the seat, do it in the trunk, sub forward port forward and seal it off from the trunk. Best bang for the buck in a car SPL setup.

[rbgnwa45]

Oh for the love of Pete Moss lol, for the third or fourth time, THE BOX HAS NEVER BEEN PLANNED TO, AND WILL NEVER BE MADE OF PLYWOOD. I'm not that inconsiderate/inept, my last box was 1" MDF and costed $300. The walled portion will be made of plywood, and not so little that it's flimsy. It's just to seperate the air spaces from front & back. I don't want to look back and see a box, I want to look back and see a wall with ports this time. I've thought about doing a sealed off trunk, just because I could pull it out of the trunk and wall it while it's sitting on the back seat... and that's probably an even better idea, that would atleast give me flexability if I ever wanted my back seat back.

The ported box would be:

.75" MDF
1.5" baffle
.75" counter-sunk (I really dunno if that's even needed, I hear it helps for smoothing out standing waves or something)
21" height (outside) - the max. height (floor to bottom of rear deck - I'd be ripping out the trunk cross bars that help the trunk lid move easily)
38" width (outside) (maximum width, metal to metal - it's like 38.1")
30" depth (outside) - still leaves room for the back seat to be on the same angle when up. I'd have to relocate the rear seat locker or just throw it out.
Port 6.5 W x 19.5 H x 26 depth
Port on passenger side (because the rear seat is like 30/70 split)
14.15" of port area per cubic foot

21 x 30 is conveniently right around the maximum squared dimension I can fit through the back door.

It comes out close to 8.95 NET @ 32.875 Hz.

I tried the XXX sealed in 1 cube in a hatchback, 1500W and it sucked so much.

I hate trial & error. I thought designing a bandpass was like calculate-and-go.

[Scro]

I'm just going to point out the pink elephant in the room. If you have the chance to consult with one of the best in the business, Steve Meade, your not going to get much better advice on a quad forum. It's like asking me how to win a GNCC race, when you've already talked with Ballance.:p

[ZBlaster]

Originally posted by rbgnwa45
Oh for the love of Pete Moss lol, for the third or fourth time, THE BOX HAS NEVER BEEN PLANNED TO, AND WILL NEVER BE MADE OF PLYWOOD. I'm not that inconsiderate/inept, my last box was 1" MDF and costed $300. The walled portion will be made of plywood, and not so little that it's flimsy. It's just to seperate the air spaces from front & back. I don't want to look back and see a box, I want to look back and see a wall with ports this time. I've thought about doing a sealed off trunk, just because I could pull it out of the trunk and wall it while it's sitting on the back seat... and that's probably an even better idea, that would atleast give me flexability if I ever wanted my back seat back.

The ported box would be:

.75" MDF
1.5" baffle
.75" counter-sunk (I really dunno if that's even needed, I hear it helps for smoothing out standing waves or something)
21" height (outside) - the max. height (floor to bottom of rear deck - I'd be ripping out the trunk cross bars that help the trunk lid move easily)
38" width (outside) (maximum width, metal to metal - it's like 38.1")
30" depth (outside) - still leaves room for the back seat to be on the same angle when up. I'd have to relocate the rear seat locker or just throw it out.
Port 6.5 W x 19.5 H x 26 depth
Port on passenger side (because the rear seat is like 30/70 split)
14.15" of port area per cubic foot

21 x 30 is conveniently right around the maximum squared dimension I can fit through the back door.

It comes out close to 8.95 NET @ 32.875 Hz.

I tried the XXX sealed in 1 cube in a hatchback, 1500W and it sucked so much.

I hate trial & error. I thought designing a bandpass was like calculate-and-go.

Designing a good bandpass is all about some trial and error with the loading wall and port lengths. It's all about making it respond the best to your car and how it peaks. It's not something simple like sitting it in and playing it, althought I wish it was haha.

If you're going to be reconing to an 18" then by all means 8.95 net in the trunk will work nicely, and get plenty loud. I'd suggest making a removable port and experimenting with tuning instead of just doing a dead set tuning. all vehicles respond different, and having it in the trunk facing forward you will lose some low end out put so you may want it a little lower for daily, or you may decide to tune it up a little further for SPL purposes. I usually like to make it easily removable and make 2 or 3 ports depending on what your wanting to do with it at the time.

Even in a standard box with it that big you'll need some bracing from top to bottom and front to back. a 38x30 sheet of .75 MDF will flex like crazy with a XXX playing hard in it. Get some threaded rod or small dowel and use them, be sure to account for them in your dimensions because it will change tuning slightly, but the lack of flex will make up for the loss of net volume in the end.

Really try to squeeze 15-16 in^2 per cube on port, if you're that close it shouldn't be hard.

I'd really give up on the bandpass idea for a while, build you a good setup sealed off from the trunk and enjoy it. While you have it in you can do some research, PM some people who know their stuff, and learn how the bandpass works and how to design one. Also HarrisTech's BassBoxPro6 has a good bandpass calculator that will help some, but in the end it'll be trial and error.

[rbgnwa45]

Thanks. If you insist, I'll give up the 4th order. I'll be happy with a big ported box tuned low.

Why 15-16 per cubic foot? I thought a port ratio of up to 1:3 was OK. More air flow, great, but 6.5 x 19.5 is a pretty big space already.

My last box was 2.2 @ 36-37 Hz and it fell off hard after tune. I'm okay with 33 Hz, it seems like a big enough box to even be a little peaky on the low end, but I like that. I'm more worried about the sub over excurting than I am my SQ preference, I'm pretty sure any tune I'll be happy as long as it doesn't break. I had 2 sealed Eclipse SW8200's for awhile and they did an insane job of covering 20-30 Hz with little space & power.

The 21 x 38 x 30 was the max dimensions of the trunk.

I don't want trunk rattles, I'd prefer it to be sealed off. I've tried sub forward with port to the side and the lows weren't nearly as good and it was quieter. I don't think sub & port rear fire would do much good because the trunk is "only" 21" high and the sub is 18.5" outer diameter, so I'm stuck for box positioning.

How much power can 3 batteries sustain with an alt big enough to sustain the batteries?

Does space equate to SPL? I thought less space was better. I ask because if 2 12's have almost as much cone area as an 18 and handle twice the power, but the 18 can be put in a box twice as large than do they about equal out given that the tune and everything else is the same?

[ZBlaster]

Originally posted by rbgnwa45
Thanks. If you insist, I'll give up the 4th order. I'll be happy with a big ported box tuned low.

Why 15-16 per cubic foot? I thought a port ratio of up to 1:3 was OK. More air flow, great, but 6.5 x 19.5 is a pretty big space already.

My last box was 2.2 @ 36-37 Hz and it fell off hard after tune. I'm okay with 33 Hz, it seems like a big enough box to even be a little peaky on the low end, but I like that. I'm more worried about the sub over excurting than I am my SQ preference, I'm pretty sure any tune I'll be happy as long as it doesn't break. I had 2 sealed Eclipse SW8200's for awhile and they did an insane job of covering 20-30 Hz with little space & power.

The 21 x 38 x 30 was the max dimensions of the trunk.

I don't want trunk rattles, I'd prefer it to be sealed off. I've tried sub forward with port to the side and the lows weren't nearly as good and it was quieter. I don't think sub & port rear fire would do much good because the trunk is "only" 21" high and the sub is 18.5" outer diameter, so I'm stuck for box positioning.

How much power can 3 batteries sustain with an alt big enough to sustain the batteries?

Does space equate to SPL? I thought less space was better. I ask because if 2 12's have almost as much cone area as an 18 and handle twice the power, but the 18 can be put in a box twice as large than do they about equal out given that the tune and everything else is the same?

The XXX LOVES port area, 15-16 would be ideal for it, less would work but they like them big.

Usually no matter where you tune you'll play a little above and below tuning well. I like to stick lower because I do more ground pounding than anything. 30-35 is my usual range although I have done 38-40 on some of my bassrace setups. You won't need to worry about over excursion much at your power level, just make sure it's tuned good by an oscope or DMM if one isn't available, of course don't use bass boost, etc.

Sealed off from the trunk sub forward, port forward has been proven to excel on the meter. IF you don't want to seal it off sub up port back works, if you want to seal it off sub and port into the cabin is the way to go. You'll notice BIG gains on the meter with them both forward and sealed off as opposed to port back. My buddy gained 4.2 by going from sub back port back to sub forward port forward, filler walls on each side, and expanding foam to finish sealing it with the same core box. The difference is pretty large.

Batteries all depend on charging system, and which batteries you start with. I use SVR AGM batteries, 1 under the hood 2 in the back. I have my big 3 done in 2/0, and 2 runs of B+ 1/0 and 2 runs of - 1/0 to the back batteries along with a 250amp alt. They work awesome, and I've yet to have a voltage issue. For the amp you mentioned I'd do my big 3, good under the hood battery then add a second battery in the back. Stock alt should be sufficient, and 2 will work just fine for you.

Space does not necessarily equal SPL. When it comes to box size running larger than required works well with less power, and when you add sufficient power slightly smaller will perform better without damaging the woofer. The larger box lowers power handling, but also can compensate slightly for less wattage. When it comes to cone area bigger displaces more air. Doesn't necessarily mean it will or will not be louder. Usually if your going with the same type of sub either way if you have the airspace more cone area is obviously going to meter higher. 2 12's vs 1 18" would be a toss up. I vote 2 12's for more displacement. 1 18" will get wicked though.

[rbgnwa45]

2 12's have 226" of cone area and 1 18 has 254?

A .75" x 27.75" threaded rod takes up like .0007 cubes, hopefully the tune won't go over 33 Hz.

Are there 6 sided rod dividers so that rods can all be directly through the middle of the air space? Front to back, top to bottom, side to side. Would the side to side one go through the port? Do the port walls flex?

I can't just squeeze out more port area, the tune will go past 33 Hz, I don't really want to go above that, so 6.5 x 19.5 is good with me. I can't make the box much longer or it won't fit through the door.

Is a 1.5" baffle enough?

Check out this beat I made :devil:

http://tesla.plunder.com/x/$FhG6EAjNGAdq-b6qLsinZKPgeZLENNxc/24cb9af95a/stomp.wma

[ZBlaster]

Originally posted by rbgnwa45
2 12's have 226" of cone area and 1 18 has 254?

A .75" x 27.75" threaded rod takes up like .0007 cubes, hopefully the tune won't go over 33 Hz.

Are there 6 sided rod dividers so that rods can all be directly through the middle of the air space? Front to back, top to bottom, side to side. Would the side to side one go through the port? Do the port walls flex?

I can't just squeeze out more port area, the tune will go past 33 Hz, I don't really want to go above that, so 6.5 x 19.5 is good with me. I can't make the box much longer or it won't fit through the door.

Is a 1.5" baffle enough?

Check out this beat I made :devil:

http://tesla.plunder.com/x/$FhG6EAjNGAdq-b6qLsinZKPgeZLENNxc/24cb9af95a/stomp.wma

I meant woofer quantity by displacement, not necessarily cone area. I'm not a big fan of single sub.

You should have plenty of bracing with 2 or 3 sections from front to back and top to bottom. Port walls won't flex that much. Just the big pieces (top, bottom, front, back) that will be more likely to flex.

Have you already L'ed your port? I'm telling you from experience XXX's LOVE port, 15-16 they really excel. If any way possible play with it as much as possible, it will pay off in the long run.

1.5" should be enough but because I like overkill I'd do 1.5" under the sub, and flushmount it with another sheet. 2.25" total.

My shop computer speakers blow chunks, I'll have to check out the beat when I get home. Look up some Decaf stuff, his gets wicked in my truck.

[rbgnwa45]

Originally posted by ZBlaster
I meant woofer quantity by displacement, not necessarily cone area. I'm not a big fan of single sub.

You should have plenty of bracing with 2 or 3 sections from front to back and top to bottom. Port walls won't flex that much. Just the big pieces (top, bottom, front, back) that will be more likely to flex.

Have you already L'ed your port? I'm telling you from experience XXX's LOVE port, 15-16 they really excel. If any way possible play with it as much as possible, it will pay off in the long run.

1.5" should be enough but because I like overkill I'd do 1.5" under the sub, and flushmount it with another sheet. 2.25" total.

My shop computer speakers blow chunks, I'll have to check out the beat when I get home. Look up some Decaf stuff, his gets wicked in my truck.

D'oh! I didn't even think of L'ing the port, I never liked doing that.

How long of a port is too long? What if it did have 16" of port per cube, would it still be better? Everybody tells me over 22" port depth is bad but then I see port lengths up to 40"?

I think I'll give 1.5" under the sub so the screws have more to hold onto, and flush mount .75".

I never thought about this but I could even flare that port :chinese:.

[ZBlaster]

Originally posted by rbgnwa45
D'oh! I didn't even think of L'ing the port, I never liked doing that.

How long of a port is too long? What if it did have 16" of port per cube, would it still be better? Everybody tells me over 22" port depth is bad but then I see port lengths up to 40"?

I think I'll give 1.5" under the sub so the screws have more to hold onto, and flush mount .75".

I never thought about this but I could even flare that port :chinese:.


How long is too long is an iffy thing, everyone has their own opinion. Usually 22-24 is as far as I want to go, but I've seen people run them twice that long before with good results. I'd try to get 15-16" of port, but not go too long. If you can get it close to 22-24 you should be fine, heck even further you may be fine.

1.5 under and .75 flushmount will add good strength, and look baller. Consider t-nuts for mounting that sub in as well.

[rbgnwa45]

What are T-Nuts? I don't think I've ever heard of that. Basically bolted from each side of the baffle with washers? No washers?

It won't look baller as it'd be hidden anyways. T nuts though.

[ZBlaster]

Originally posted by rbgnwa45
What are T-Nuts? I don't think I've ever heard of that. Basically bolted from each side of the baffle with washers? No washers?

It won't look baller as it'd be hidden anyways. T nuts though.


Not really for looks, just more or less to keep the screw holes from stripping out if you have to pull the sub, and with a sub that heavy it adds assurance to it anyways.

http://caraudiomag.com/pictures/install-t-nuts-first

[rbgnwa45]

I'm confused. There's nothing on the other end of that nut. It's a little bigger at the very end, but how is that thing gonna stay in the wood? Obviously it has a gripper-thing on one end, but what happends on the other side? It doesn't look like it's got much diameter. It's like an inside-out screw, and it's messing with my head @ 3AM.

[Scro]

The nut is treaded on the inside. You drill the holes the size of the flange on the nut, and then hammer the prongs into the wood. You will use bolt to install the sub, instead of wood screws.

[ZBlaster]

Originally posted by Scro
The nut is treaded on the inside. You drill the holes the size of the flange on the nut, and then hammer the prongs into the wood. You will use bolt to install the sub, instead of wood screws.


He nailed it. Basically your putting metal inserts in to bolt the sub down with instead of using screws in the soft MDF. when using screws in the MDF with a sub that heavy you run the risk of them eventually breaking out, and the more times you put in the sub and remove the sub the holes will strip out.

[rbgnwa45]

Good idea. This thing weighs ~79lbs. I can barely carry it without my fingers getting new seams. I once took it to a small audio shop, they never seen anything like it, blew their minds haha.

It makes sense, but is there a washer on one side? It looked like the bolt flange was small.

No washer? Wouldn't that lil flange just rip through the wood?

http://caraudiomag.com/sites/default/files/images/00000/80/02/test_fit_subwoofer.jpg

[ZBlaster]

Originally posted by rbgnwa45
Good idea. This thing weighs ~79lbs. I can barely carry it without my fingers getting new seams. I once took it to a small audio shop, they never seen anything like it, blew their minds haha.

It makes sense, but is there a washer on one side? It looked like the bolt flange was small.

No washer? Wouldn't that lil flange just rip through the wood?

http://caraudiomag.com/sites/default/files/images/00000/80/02/test_fit_subwoofer.jpg


Once you drive it in and it bottoms out on the flange it'd be like trying to pull the flange through 1.5" of wood. Won't happen. And since it doesn't thread in there is very little chance of it stripping out. They are well worth the money.

[kbnorth99]

Is it just me or does the title of this thread sound like some sort of strange cult for musicians? You know a secret handshake and a tattoo of a skull and crossed trombones?

.....sorry I just couldn't resist. :p

[rbgnwa45]

LMAO!

Drinks are ON THE HOUSE!





;)

[rbgnwa45]

Originally posted by ZBlaster
Once you drive it in and it bottoms out on the flange it'd be like trying to pull the flange through 1.5" of wood. Won't happen. And since it doesn't thread in there is very little chance of it stripping out. They are well worth the money.

I think it just didn't fit right in my mind. That flange needs a washer. It doesn't look right :ermm:.

What size is best? What sizes do they come in? Do you lock the other side with a nut... wait that'd be impossible unless you mounted the sub then built the box, which would defeat the purpose of using T-Nuts... hmmm :chinese:.

Don't they ever come loose if there's nothing on the other side holding them? I think a screw would have less a chance of coming out.

Watch this box jumping on Singers' channel, it's nuts!

http://www.youtube.com/watch?v=ExU5mvJsYXk&feature=feedf

Here's some more beats...

Kung Fu
http://tesla.plunder.com/x/$cbMIKUbbA9rB9Kj7LhP1mOAom-084aNq/601435744a/Kung%20Fu.wma

Kung Fire
http://tesla.plunder.com/x/$cbMIKUbbA9pv__V5lVMJKLZR-CZgpAsI/b4156b3353/Kung%20Fire.wma

Luigi Lettuce
http://tesla.plunder.com/x/$cbMIKUbbA9oG_sEXuyGZR576NrYQwmLw/04257ddd84/Luigi%20Lettuce%203.wma

Lunar Toast
http://tesla.plunder.com/x/$cbMIKUbbA9rTuJJdsjn0EcCia1SdZwAm/be53fd4535/Lunar%20Toast.wma

Stereo Samurai
http://tesla.plunder.com/x/$FhG6EAjNGAdq-b6qLsinZKPgeZLENNxc/24cb9af95a/stomp.wma

Surgery Circus
http://tesla.plunder.com/x/$cbMIKUbbA9rx7GsbLMxLI1ZqgltZFBXt/ba70a4babd/Surgery%20Circus.wma

[rbgnwa45]

I've calculated with an L'd port, and it was a b!tch:

Port 6.61 x 19.5 x 38.5 depth

= 8.06379 NET @ 29.997 Hz

15.9844" of port area per cubic foot.

:eek2:.

:huh 38.5 depth

Versus what I had before (well, after adding a flush mount)...

Port 6.5 x 19.5 / 8.8 NET @ 33.155 Hz with 14.4" of port area per cube and 26" port depth.

This is why I do not like L-ing ports!

Without L'ing the port,

15" per cube (6.75 x 19.5 x 25.875 depth) = 8.727 NET @ 33.9 Hz

15.78" per cube (7 x 19.5 x 25.75 depth) = 8.65 NET @ 34.66 Hz

16.06" per cube = (7.1 x 19.5 x 25.7 depth) = 8.62 NET @ 34.96 Hz

16.48" per cube = (7.25 x 19.5 x 25.625 depth) = 8.57477 NET @ 35.4085 Hz

I HATE DECIMALS! :scary:

[ZBlaster]

Originally posted by rbgnwa45
I've calculated with an L'd port, and it was a b!tch:

Port 6.61 x 19.5 x 38.5 depth

= 8.06379 NET @ 29.997 Hz

15.9844" of port area per cubic foot.

:eek2:.

:huh 38.5 depth

Versus what I had before (well, after adding a flush mount)...

Port 6.5 x 19.5 / 8.8 NET @ 33.155 Hz with 14.4" of port area per cube and 26" port depth.

This is why I do not like L-ing ports!

Without L'ing the port,

15" per cube (6.75 x 19.5 x 25.875 depth) = 8.727 NET @ 33.9 Hz

15.78" per cube (7 x 19.5 x 25.75 depth) = 8.65 NET @ 34.66 Hz

16.06" per cube = (7.1 x 19.5 x 25.7 depth) = 8.62 NET @ 34.96 Hz

16.48" per cube = (7.25 x 19.5 x 25.625 depth) = 8.57477 NET @ 35.4085 Hz

I HATE DECIMALS! :scary:


Your actually only looking at around 12" more length to when doing the L to get the tuning you want, I say go for it. Your already using a long port anyway. Are you figuring in end correction as well?

The T nuts work awesome, as for size I can't remember right off, I got a bag full at a small local hardware that looked about the right size. They will not break loose once in.

[rbgnwa45]

8 NET @ 30 Hz with 16" per cube does sound enticing :devil:.

- yes on the end correction, half the port width.

[dehner47]

not tryin to high jack this thread... but is anyone of you guys looking for a nice set of Boston Acoustic door speakers?? got a brand new set for sale..

https://post.craigslist.org/manage/2450388413/a24s7

sorry again for high jacking the thread..

[ZBlaster]

Originally posted by rbgnwa45
8 NET @ 30 Hz with 16" per cube does sound enticing :devil:.

- yes on the end correction, half the port width.


Sounds perfect to me. Should be nutty loud with good power.

[rbgnwa45]

Originally posted by dehner47
not tryin to high jack this thread... but is anyone of you guys looking for a nice set of Boston Acoustic door speakers?? got a brand new set for sale..

https://post.craigslist.org/manage/2450388413/a24s7

sorry again for high jacking the thread..

You weren't trying to high jack this thread, but you did, and you were in full knowing, and apologized for it! I guess that makes it OK?

High jack away :huh.








http://i21.photobucket.com/albums/b258/EvilAerosolCan/Threadjack.jpg








Just playin' :p








http://forums.unfiction.com/forums/files/thumbs/t_threadjack_831.jpg








Don't high jack my thread :ermm:.








http://i36.photobucket.com/albums/e5/Kommander_Cool/Random/THREADJACK.gif?t=1278515066








Just playin' :devil:.








http://i32.photobucket.com/albums/d46/cell_dweller/thread_direction.gif








High jack away :D.








http://www.buffettworld.com/forum/forumimages/HIJACK_onplane.gif








I'd like to try out the Audioque component set for ~$199.

Is this car not sick or what?

http://www.ersenosman.com/car/safcar.jpg

[rbgnwa45]

Ninja Jesus
http://tesla.plunder.com/x/$cbMIKUbbA9pWAjIbTephDadvnMnHRPSO/5fcf83d24f/Ninja%20Jesus.wma

[ZBlaster]

From what I've heard the AQ components get pretty harsh. I haven't heard them myself, just what I've read/heard.

For about $10 more you can pick up some Hertz Mille components, and they sound effing amazing.

[Zakradu398]

Originally posted by dehner47
not tryin to high jack this thread... but is anyone of you guys looking for a nice set of Boston Acoustic door speakers?? got a brand new set for sale..

https://post.craigslist.org/manage/2450388413/a24s7

sorry again for high jacking the thread..

Massages? :huh :D

[dehner47]

Originally posted by Zakradu398
Massages? :huh :D

ummmm yaaaa... i have no idea where that came from.. but hell, a mans gotta make some extra cash now and then dont he.. haha

[rbgnwa45]

I heard a wall of 16 Hertz Mille 6.5's and they sounded so clear and amazing, definetly my favourite of all time. They're in the car audio department at East Hamilton Radio along with 16 ported Hertz 12's. It's a frickin' sweet wall. :D

[rbgnwa45]

Played with some new sounds. I usually keep it under 131 beats per minute - this is 350 BPM! Lots of bass.

Agent 99 (http://tesla.plunder.com/x/$ih_zIt8L0gRQJL5EUix48DKWpW3hllTA/7ba5a09d71/Agent%2099.wma)