anyone want to help out a n00b with box design?

[SSS 18734 0]

http://www.caraudio.com/vb/showthread.php?t=115401

I started a thread on CA.com, im trying to come up with a good box, and im not really too happy with the frequency response my 2000SPL's offer using WinISD. This being a more serious, on topic forum, does anyone have any suggestions or answers to the questions asked on that thread?

feel free to post either here or on CA.com

Thanks!

Sergei

[mrray13 30]

what exactly is ur current setup?

playing around, i've got the best looking graphs to be about 4ft^3, tuned to 35hz, with two 4" round ports...ur lowend roll off starts at about 40hz...it's at -6db at 30hz, not counting car transfer funtion.

anyway...i used 1kw as total input power..and the t/s specs from pioneers website...

i'm sure we can do better with a bit more info....

wheeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeee

[Lord Baccus 1]

need to know what sub modle you are using and T/S info, also will need to know the external dimentions of where you intend to put the box so we get a good fit and also dont forget to measure the trunk opening so it will go in after its built ! a lot of people forget this and cant get the box in the trunk after its built

i am using Bas Box Pro 6 let me know if i can help

this is a pic of my last build 8.03cf @ 40Hz after displacement of subs & ports

[Tirefryr 1,742]

Don't pay much attention to the computer modeling graphs on widely available cheap or free programs. They are not too accurate. Even my $200 program is way off. You just can't simple rely on a computer programs "estimated" response.

The higher end programs (read espensive) such as LEAP are very good, but also very pricy. I'd do a search and see what other are using and go from there, or start with the manufacturer's suggestions and tweak to your liking.

I have had great experiences using Pioneers recommendations as a base and tweaking them where needed. The Manufacturers DO know their products well and their capabilities.

[MrCabinetry 0]

Don't pay much attention to the computer modeling graphs on widely available cheap or free programs.  They are not too accurate.  Even my $200 program is way off.  You just can't simple rely on a computer programs "estimated" response. 

The higher end programs (read espensive) such as LEAP are very good, but also very pricy.  I'd do a search and see what other are using and go from there, or start with the manufacturer's suggestions and tweak to your liking. 

I have had great experiences using Pioneers recommendations as a base and tweaking them where needed.  The Manufacturers DO know their products well and their capabilities.

<{POST_SNAPBACK}>

Tirefryr,

While I have to agree with you about enclosure modeling programs as being wholly inaccurate as to the cheap or online programs.

In my experieence using Bass Box Pro 6 given all the enclosure's that I have designed and built and delivered, BBP 6 has yet to provide any unsatisfactory comments from any of those customers.

As we all know, enclosure design programs are intended to be used as a tool to at least provide within reasonable expectations of bass response and performance given all the other known factors involved that are going to effect the subwoofer/enclosure after they are installed in the vehicle.

[SSS 18734 0]

I've been doing a lot of calculations and I came up with a somewhat finalized box using WinISD. As for being perfectly accurate, im not too worried about that, im not going for perfection, but my main goal here is flat response up until the lower frequencies, where I'd like to have a large peak. The thread that I linked you guys too earlier I entered using the wrong T/S Parameters, which is why I have a huge dip in the mid-high bass frequencies.

2 12" 2000SPL's

4.00 cu.ft @34hz

2 slot ports, 2.5" wide, 11" tall, 28" long

+plenty of bracing

I have a station wagon, so space and getting the box in is not a major concern, but I would like to keep the demensions around 36" width (necessary), 24" depth, and 14" hight

Heres what the graph I came up with looks like:

And the box will look something like this, subs facing up, ports facing back.

Any opinions? comments? suggestions?

[Tirefryr 1,742]

Don't pay much attention to the computer modeling graphs on widely available cheap or free programs.  They are not too accurate.  Even my $200 program is way off.  You just can't simple rely on a computer programs "estimated" response. 

The higher end programs (read espensive) such as LEAP are very good, but also very pricy.  I'd do a search and see what other are using and go from there, or start with the manufacturer's suggestions and tweak to your liking. 

I have had great experiences using Pioneers recommendations as a base and tweaking them where needed.  The Manufacturers DO know their products well and their capabilities.

Tirefryr,

While I have to agree with you about enclosure modeling programs as being wholly inaccurate as to the cheap or online programs.

In my experieence using Bass Box Pro 6 given all the enclosure's that I have designed and built and delivered, BBP 6 has yet to provide any unsatisfactory comments from any of those customers.

As we all know, enclosure design programs are intended to be used as a tool to at least provide within reasonable expectations of bass response and performance given all the other known factors involved that are going to effect the subwoofer/enclosure after they are installed in the vehicle.

Oh, I'm not saying it may produce an unsatisfactory result, I just don't want him to base his final enclosure based on nothing more than a plotted response graph from program. All I was trying to get through to him.

OT: Nice to see you on the board!

[Lord Baccus 1]

i did a moc up of your box in BBP6

Box Properties

Name:

Type: Vented Box

Shape: Prism, square

Vb = 4 cu.ft

Fb = 33.99 Hz

Fill = none

No. of Vents = 2

Vent shape = rectangle

Vent ends = two flush

Hv = 12.5 in

Wv = 2.5 in

Lv = 33.59 in

[SSS 18734 0]

that looks like a sealed design to me

BTW, I would like to have indented sides for this particular box. I suck at carpeting

[mrray13 30]

the biggest downside to bb6p is that is doesn't figure slot ports accurately, as it pertains to the port's displacment. it also assumes you are going to build the port seperately and not use a wall as part of the port...you have to tweak the program a bit to get it close.

otherwise, i'm extremely happy with bb6p and the results it's given me..however, i agree with ryan. while it will indeed give you an idea, one should not wholey rely upon it's graphs...unless you want to take the time to map out the frequency response of your vehicle so that the graph's can use the vehicle response as well. even then, i won't just assume that the bb6p graphs are 100% accurate.

wheeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeee

[MrCabinetry 0]

the biggest downside to bb6p is that is doesn't figure slot ports accurately, as it pertains to the port's displacment. it also assumes you are going to build the port seperately and not use a wall as part of the port...you have to tweak the program a bit to get it close.

otherwise, i'm extremely happy with bb6p and the results it's given me..however, i agree with ryan. while it will indeed give you an idea, one should not wholey rely upon it's graphs...unless you want to take the time to map out the frequency response of your vehicle so that the graph's can use the vehicle response as well. even then, i won't just assume that the bb6p graphs are 100% accurate.

wheeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeee

<{POST_SNAPBACK}>

Well, BBP 6 does calculate a slot port accurately given the way the program does model it within the Box Volume Displaced by the Port parameters.

However, within those parameters, it has to be specified what the thickiness of the material being used noted by input " B ".

The Box Volume Displaced by the Port parameters are not making any assumptions here, they are performing the function properly

based on the manner which the program was written to calculate either a round or slot port not to include any part of the enclosure itself.

So, like a round port which is calculated to lenght based on the volume, diameter & tuning frequency, a slot port is calculated in the

same manner as if it were a separate part installed.

Now, given that the majority of the time when we design ported enclosure's using slot ports, we're going to use the top, bottom, side & back for

part of the slot port walls. This leave's us with only having to determine the final port wall or walls that make up the rest of the slot port which

we have to figure out their displacement which changes the parameters of the enclosure design.

LB ( Lord Baccus ) asked me this question awhile back when he was trying to figure out a slot ported design in BBP 6 and his calculations were getting

totally throw off because he could not understand which parameters within the program were causing the conflicting issue's.

Rather than trying to explain it to him, he sent me his BBP 6 design and I sent him back my BBP 6 design of the same enclosure and

referenced those parameters within the program to show the errors within the formula, once he saw both designs side by side, he got

it just like that.

Your are totally correct, when designing slot ports within BBP 6, you have to totally zero out the parameters in the Box Volume Displaced by the Port parameters and use the Box Volume Displaced by Miscellaneous Objects to properly calculate the slot port parameters to account for both the Port Displacement and Port Wall Displacements.

Granted, it's a royal PITA to calculate the slot port parameters accurately because you have to constantly re-adjust all the other parameters but I've discovered a few tweaks and using a calculator I created in EXCEL, I've reduced the amount of effort I need to apply for designing slot ported boxes in BBP 6 and in turn allow me to build enclosure's with a greater degree of satisfactory results in terms of bass response and performance once the customer recieves and installs the enclosure.

We all agree that the other factors involved after the sub/enclosure are installed are going to skew the bass response/performance, none of us can deny that unknown element.

Phil

Woodlawn Cabinetry

( NOT KENT )

[mrray13 30]

the biggest downside to bb6p is that is doesn't figure slot ports accurately, as it pertains to the port's displacment. it also assumes you are going to build the port seperately and not use a wall as part of the port...you have to tweak the program a bit to get it close.

otherwise, i'm extremely happy with bb6p and the results it's given me..however, i agree with ryan. while it will indeed give you an idea, one should not wholey rely upon it's graphs...unless you want to take the time to map out the frequency response of your vehicle so that the graph's can use the vehicle response as well. even then, i won't just assume that the bb6p graphs are 100% accurate.

wheeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeee

Well, BBP 6 does calculate a slot port accurately given the way the program does model it within the Box Volume Displaced by the Port parameters.

However, within those parameters, it has to be specified what the thickiness of the material being used noted by input " B ".

The Box Volume Displaced by the Port parameters are not making any assumptions here, they are performing the function properly

based on the manner which the program was written to calculate either a round or slot port not to include any part of the enclosure itself.

So, like a round port which is calculated to lenght based on the volume, diameter & tuning frequency, a slot port is calculated in the

same manner as if it were a separate part installed.

Now, given that the majority of the time when we design ported enclosure's using slot ports, we're going to use the top, bottom, side & back for

part of the slot port walls. This leave's us with only having to determine the final port wall or walls that make up the rest of the slot port which

we have to figure out their displacement which changes the parameters of the enclosure design.

LB ( Lord Baccus ) asked me this question awhile back when he was trying to figure out a slot ported design in BBP 6 and his calculations were getting

totally throw off because he could not understand which parameters within the program were causing the conflicting issue's.

Rather than trying to explain it to him, he sent me his BBP 6 design and I sent him back my BBP 6 design of the same enclosure and

referenced those parameters within the program to show the errors within the formula, once he saw both designs side by side, he got

it just like that.

Your are totally correct, when designing slot ports within BBP 6, you have to totally zero out the parameters in the Box Volume Displaced by the Port parameters and use the Box Volume Displaced by Miscellaneous Objects to properly calculate the slot port parameters to account for both the Port Displacement and Port Wall Displacements.

Granted, it's a royal PITA to calculate the slot port parameters accurately because you have to constantly re-adjust all the other parameters but I've discovered a few tweaks and using a calculator I created in EXCEL, I've reduced the amount of effort I need to apply for designing slot ported boxes in BBP 6 and in turn allow me to build enclosure's with a greater degree of satisfactory results in terms of bass response and performance once the customer recieves and installs the enclosure.

We all agree that the other factors involved after the sub/enclosure are installed are going to skew the bass response/performance, none of us can deny that unknown element.

Phil

Woodlawn Cabinetry

( NOT KENT )

that's jsut what i was referring too, but i didn't put it so nicely, lol. you'll get used to me like that.

and, btw, i'm Kent. nice to meet ya Phil!

wheeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeee:slayer:

[Jmac 24]

BB6P is great, IMO ... Calculating slot displacement is easy ...

Of course, I'd love to get my hands on LEAP 5.0 ... Unfortunately, I don't have $1200 laying around nor do I know where to get it for free ...

[Supa_c 1]

I can swing by TC sounds and steal me a copy

[Lord Baccus 1]

if ya do can i get a copy ?

[Supa_c 1]

sorry man...you dont have enough posts

[Lord Baccus 1]

can i transfer post from another forum comeon i would help you