Well I've been messin around with WinISD for the past hour, converting units to metric and back again, etc. All I can say is, I'm completely lost. In case you haven't read any of my other posts, here's my equipment:

(1) 18" Fi BTL N2

(1) AQ2200D

(1) XS Power D1200

Those are the only things I have purchased so far. Right now I'm trying to figure out what I'm gonna do about the box. I think I'm gonna go with a slot ported box, tuned in the upper 30s/lower 40s. Only problem is, the process of designing a box that won't sound like shit is a tough task that is starting to become overwhelming.

First question: How do you know what size box to put into a calculator such as this one if you don't even have it built yet? Isn't that defeating the purpose? Seems awfully backwards to me.. I'm obviously missing something here.

Next question: How much volume of the port counts towards the volume that the subwoofer is seeing? For instance, in the following picture, does the space marked in black count for interior cubic feet or space of the port?

I'm gonna have a lot more questions, and I hope this is the proper place to ask them. I'm building the box with my stepdad this weekend. He's excellent with woodworking, but he knows as much about subwoofer box building as I do (basically nothing).

Edited April 27, 201114 yr by burko

First question: How do you know what size box to put into a calculator such as this one if you don't even have it built yet? Isn't that defeating the purpose? Seems awfully backwards to me.. I'm obviously missing something here.

Next question: How much volume of the port counts towards the volume that the subwoofer is seeing? For instance, in the following picture, does the space marked in black count for interior cubic feet or space of the port?

1) I would recommend you to use Torres' Box Calculator. Its a lot "cleaner" and easier to use imo. If you have any questions with it, feel free to PM me.

2) The more the total port displaces, the less internal airspace is in the box. The left of the black line you drew is where the port ended.

Try this box calculator and see if it helps you understand how the port will integrate into the volume of the total enclosure. Remember that the port takes up air space as does the sub and any bracing. So you will have a total volume and a net volume.

First question: How do you know what size box to put into a calculator such as this one if you don't even have it built yet? Isn't that defeating the purpose? Seems awfully backwards to me.. I'm obviously missing something here.

Next question: How much volume of the port counts towards the volume that the subwoofer is seeing? For instance, in the following picture, does the space marked in black count for interior cubic feet or space of the port?

1) I would recommend you to use Torres' Box Calculator. Its a lot "cleaner" and easier to use imo. If you have any questions with it, feel free to PM me.

2) The more the total port displaces, the less internal airspace is in the box. The left of the black line you drew is where the port ended.

I haven't started building a box yet... Do you understand how confusing this is to someone who has ZERO experience with this? How am I supposed to know the box dimensions if I don't have a box

Try this box calculator and see if it helps you understand how the port will integrate into the volume of the total enclosure. Remember that the port takes up air space as does the sub and any bracing. So you will have a total volume and a net volume.

Thats the one I recommended in my first post

Do you understand how confusing this is to someone who has ZERO experience with this?

How am I supposed to know the box dimensions if I don't have a box

Definitely. We were all there at some point.

Youre supposed to plan the dimensions before you build the box, so youre all good. With Torres' box calculator, you play around with numbers (possible dimensions).

Try this box calculator and see if it helps you understand how the port will integrate into the volume of the total enclosure. Remember that the port takes up air space as does the sub and any bracing. So you will have a total volume and a net volume.

Thats the one I recommended in my first post

Do you understand how confusing this is to someone who has ZERO experience with this?

How am I supposed to know the box dimensions if I don't have a box

Definitely. We were all there at some point.

Youre supposed to plan the dimensions before you build the box, so youre all good. With Torres' box calculator, you play around with numbers (possible dimensions).

Gotcha. I think. Prepare to have your message box filled

About how big of a sheet of mdf is about right for an 8 cube box?

Also, what size wire would be optimal for connecting the sub to the amp? I was thinking 12 gauge but I'm not sure..

Try this box calculator and see if it helps you understand how the port will integrate into the volume of the total enclosure. Remember that the port takes up air space as does the sub and any bracing. So you will have a total volume and a net volume.

Thats the one I recommended in my first post

12 guage would be fine for the subs.

Try this box calculator and see if it helps you understand how the port will integrate into the volume of the total enclosure. Remember that the port takes up air space as does the sub and any bracing. So you will have a total volume and a net volume.

Thats the one I recommended in my first post

Do you understand how confusing this is to someone who has ZERO experience with this?

How am I supposed to know the box dimensions if I don't have a box

Definitely. We were all there at some point.

Youre supposed to plan the dimensions before you build the box, so youre all good. With Torres' box calculator, you play around with numbers (possible dimensions).

Gotcha. I think. Prepare to have your message box filled

About how big of a sheet of mdf is about right for an 8 cube box?

Also, what size wire would be optimal for connecting the sub to the amp? I was thinking 12 gauge but I'm not sure..

About 4 4'x8' Sheets. Just To Be Safe.

http://www.soundsolutionsaudio.com/index.php/technical.html

Just find you a nice box on there.

Biggest you can fit or are comfortable with in your car.

Goto lowes or home depot have them cut for you

buy some wood glue while your there have fun.

BTL 18 – Ported box we recommend using 5-8 cubic feet @ 30-35Hz tuning, you can tune a little higher if you wish but we recommend keeping it close to 32hz for a daily driver. Again the same 12-16 square inches of area applies per cubic foot of volume.

I will have to check out the recommended box calculator too. WinISD is not user friendly imo.

I believe Steave Meades's forum has a usefull calculator as well.

http://www.soundsolutionsaudio.com/index.php/technical.html

Just find you a nice box on there.

Biggest you can fit or are comfortable with in your car.

Goto lowes or home depot have them cut for you

buy some wood glue while your there have fun.

BTL 18 – Ported box we recommend using 5-8 cubic feet @ 30-35Hz tuning, you can tune a little higher if you wish but we recommend keeping it close to 32hz for a daily driver. Again the same 12-16 square inches of area applies per cubic foot of volume.

The actual wood working is not the issue.. My stepdad is excellent when it comes to fabricating anything involving wood. The problem I have is tuning the box.. We'll figure something out.

But thank you for the link. I'll check it out as soon as I'm on the computer. Storm knocked all of north alabama's power out.. We could have no power for like 5 days.

I will have to check out the recommended box calculator too. WinISD is not user friendly imo.

I believe Steave Meades's forum has a usefull calculator as well.

That would be Torres calculator, http://www.stevemeadedesigns.com/board/topic/38791-torres-box-tuning-calculator-updated-310/

deff try to use the Torres Calc....seems like a very good program, only used it once so far but it worked. GOOD LUCK!! pics when its done xD

Why not just get in touch with a good enclosure designer and have them send you a design? It takes out all the guesswork if you don't really know what you're doing, then all you have to do is follow the 'prints

Why not just get in touch with a good enclosure designer and have them send you a design? It takes out all the guesswork if you don't really know what you're doing, then all you have to do is follow the 'prints

Who would you consider to be the best designer? I need it by tomorrow...

Edited April 29, 201114 yr by burko

I highly recommend going with Fi's recommended enclosure specifications. Winsd will assume you are wiring your sub in series which most t/s parameters are derived from which will be different from parallel wiring and will throw off the response curve. Also the stiffness of the BTL will give you a real funny response curve as well because it is beyond Winsd modelling ability. Nick has stated this numerous times.

I don't know if you have tried the RE Audio box calculator, but I believe it is the internal volume. It gives the port tuning, and adjusts the volume of the box when you adjust the port size. Here is the length:

http://reaudio.com/speaker_box/LPort_Box_Calc.html

I highly recommend going with Fi's recommended enclosure specifications. Winsd will assume you are wiring your sub in series which most t/s parameters are derived from which will be different from parallel wiring and will throw off the response curve. Also the stiffness of the BTL will give you a real funny response curve as well because it is beyond Winsd modelling ability. Nick has stated this numerous times.

When did I say I was straying from their recommendations? Do you mean tuning frequency? I'll probably be keeping it in the 36-37 range.. Surely straying from 32 to 36 won't cause the world to end..

I highly recommend going with Fi's recommended enclosure specifications. Winsd will assume you are wiring your sub in series which most t/s parameters are derived from which will be different from parallel wiring and will throw off the response curve. Also the stiffness of the BTL will give you a real funny response curve as well because it is beyond Winsd modelling ability. Nick has stated this numerous times.

When did I say I was straying from their recommendations? Do you mean tuning frequency? I'll probably be keeping it in the 36-37 range.. Surely straying from 32 to 36 won't cause the world to end..

Won't cause the world to end, but it may reduce the frequency range you can play.

I highly recommend going with Fi's recommended enclosure specifications. Winsd will assume you are wiring your sub in series which most t/s parameters are derived from which will be different from parallel wiring and will throw off the response curve. Also the stiffness of the BTL will give you a real funny response curve as well because it is beyond Winsd modelling ability. Nick has stated this numerous times.

When did I say I was straying from their recommendations? Do you mean tuning frequency? I'll probably be keeping it in the 36-37 range.. Surely straying from 32 to 36 won't cause the world to end..

Won't cause the world to end, but it may reduce the frequency range you can play.

I gotcha... This is a little confusing... The lower you tune, the better the SQ/lower the SPL correct? But if you tune lower, does it make it possible to play lower notes?

I highly recommend going with Fi's recommended enclosure specifications. Winsd will assume you are wiring your sub in series which most t/s parameters are derived from which will be different from parallel wiring and will throw off the response curve. Also the stiffness of the BTL will give you a real funny response curve as well because it is beyond Winsd modelling ability. Nick has stated this numerous times.

When did I say I was straying from their recommendations? Do you mean tuning frequency? I'll probably be keeping it in the 36-37 range.. Surely straying from 32 to 36 won't cause the world to end..

Won't cause the world to end, but it may reduce the frequency range you can play.

I gotcha... This is a little confusing... The lower you tune, the better the SQ/lower the SPL correct? But if you tune lower, does it make it possible to play lower notes?

The tuning frequency is just where the volume of the notes peak. As in the decibel curve.

I highly recommend going with Fi's recommended enclosure specifications. Winsd will assume you are wiring your sub in series which most t/s parameters are derived from which will be different from parallel wiring and will throw off the response curve. Also the stiffness of the BTL will give you a real funny response curve as well because it is beyond Winsd modelling ability. Nick has stated this numerous times.

When did I say I was straying from their recommendations? Do you mean tuning frequency? I'll probably be keeping it in the 36-37 range.. Surely straying from 32 to 36 won't cause the world to end..

Won't cause the world to end, but it may reduce the frequency range you can play.

I gotcha... This is a little confusing... The lower you tune, the better the SQ/lower the SPL correct? But if you tune lower, does it make it possible to play lower notes?

The tuning frequency is just where the volume of the notes peak. As in the decibel curve.

Could you elaborate a little? I don't know what the decibel curve is..

snappy commnets like "causing the word to end" around here will get you no where especially when you already stated you were over your head. If you fully read the instructions that are posted in the file with WinSd you would have a llittle understanding of the program and what each function means and shows. Yes moving from 32 to 36 hertz while keeping the same volume can have dramatic effects on responce. At a give volume tuned to 32 hertz can give you a nice flat respnonce curve, while moving tuning to 36 could give you a 3-5 db peak with an f3 way above your desired f3. When tuning low and I don't mean 32. 32 hertz is no where in the realm of low, when using an enclosure too large for the driver's Kms it is very possible for the enclosure's "f" to be way above the actual tuning.

I didn't say all that before because you stated you didn't know anything about designing an enclosure. And most of the time it is easier to give people what they need instead of giving them what they think they want.

snappy commnets like "causing the word to end" around here will get you no where especially when you already stated you were over your head. If you fully read the instructions that are posted in the file with WinSd you would have a llittle understanding of the program and what each function means and shows. Yes moving from 32 to 36 hertz while keeping the same volume can have dramatic effects on responce. At a give volume tuned to 32 hertz can give you a nice flat respnonce curve, while moving tuning to 36 could give you a 3-5 db peak with an f3 way above your desired f3. When tuning low and I don't mean 32. 32 hertz is no where in the realm of low, when using an enclosure too large for the driver's Kms it is very possible for the enclosure's "f" to be way above the actual tuning.

I didn't say all that before because you stated you didn't know anything about designing an enclosure. And most of the time it is easier to give people what they need instead of giving them what they think they want.

You ought to cut that smart ass attitude out man, I didn't ask for your fancy wording that a normal human has no idea what it means.. Got off of my topic please and I'll recieve help from real people.

And besides, I'd rather put the x in the 29cg chamber. Thinkin of goin with a 47h slant on the 63 curvature.

Edited April 29, 201114 yr by burko

A sealed box would have a flat response curve, like a line. A ported back would have a single spot on the curve, where the volume peaks at a certain frequency. That frequency would be the tuning frequency. I wish I could draw a picture for you.