box formula

crs1

Member
2007-12-08 6:58 am
years ago radio shack had a book on speaker box design with a formula using the given thiele-small parameters that comes with a driver would any one have a coppy of this formula or happen to know the best box volume for a altec lansing 405-8h sealed and ported with port diameter&length the parameters are Xmax.05 Re(ohms)6.00 Fs 90 Vas(cu.ft.).15 Ref(%) .70 Qts .47 Qms 2.92 Qes .56 thank you for any help
 
Thawach said:
Bass box pro is better than win ISD or not?;)

Martin King's sheets are probably the best of the affordable simulators and does some things the pricey ones don't.

The "official" formulas should be around all over the place (ie Brain Steele's diysubwoofers.org, and embedded in UniBox for 2 possibles)

dave
 

crs1

Member
2007-12-08 6:58 am
sorry i should have stated my plans for these speakers they are not going too be in my house i help run a haunted hay ride by my house and the enclosures don't need to be hi tec i can be off +/-10 or 15% because they will be out side and all we need to do is hear them i will be only playing sound efx on them the formula in that book was easy and quick and would put me in around 10% i had the book but i think i got lost when i had a fire at my house thank every one for help all i need is an idea of the vb for this project the programs will be very help full later for my other project though using the same speakers hell i only have 32 of them lol once again thank you for all the help and future help in this matter:xmastree:
 

Ron E

Member
2002-06-27 10:41 pm
USA, MN
Thawach said:
hello! EC8010 English language is difficult for me. But I will try to write it. For a long time it will be better.
and here is Bass box pro link http://www.ht-audio.com/

Bassbox is nothing special. Paying for box alignment software is foolish. Save your money for a crossover simulator. BTW - XOPro, by the makers of bassbox, is a total joke. Speaker workshop does more, for no $$ at all.
 

EC8010

Ex-Moderator
2003-01-18 7:57 am
Near London. UK
Ron E said:
Paying for box alignment software is foolish. Save your money for a crossover simulator.

I would agree, bass alignment is simple enough that it's not worth paying money for software to help. As for crossovers... Buy a Behringer DCX2496 to go with spare amplifiers and use it as a breadboard for experimenting with crossovers to find out what works (measure and listen).
 

Ron E

Member
2002-06-27 10:41 pm
USA, MN
There are two simple formulas for box size both have the form:

Vb = Cv * Vas * Qts^Ev
Fb = Cb * Fs *Qts^Eb

-------- Cv --------- Ev ----------- Cb ---------- Eb
Keele : 15 --------- 2.87 --------- 0.42 -------- -0.9
Small : 20 ---------- 3.3 ---------- 0.42 -------- -0.96

Both work fine for woofers with Qts between ~.25 and .5
 
Ron E said:

Paying for box alignment software is foolish.

EC8010 said:
I would agree, bass alignment is simple enough that it's not worth paying money for software to help.

Well, I would disagree. It is true that there are nice people out there offering good software for free, but i would not say that it is foolish to pay something for their effort.

These people often have a "donate" button on their websites, but judging from my own experience people hardly ever donate anything. In the long run this leads to less free software, which is a pity.

Had people donated anything for my software (like The Edge and others), I would probably have offered my simulator Basta! for free too. Judging from the amount of downloads, and the comments I see on fora, it is not the quality of the software that causes the lack of donations.

Of course I am biased in this, but I think one should be careful spreading the attitude that paying for software is foolish. Developers, in particular those who develop free software should be encouraged, and not taken for granted.

... so, now I have said that. Now I am nice again. :)
 

crs1

Member
2007-12-08 6:58 am
Svante said:




Well, I would disagree. It is true that there are nice people out there offering good software for free, but i would not say that it is foolish to pay something for their effort.

These people often have a "donate" button on their websites, but judging from my own experience people hardly ever donate anything. In the long run this leads to less free software, which is a pity.

Had people donated anything for my software (like The Edge and others), I would probably have offered my simulator Basta! for free too. Judging from the amount of downloads, and the comments I see on fora, it is not the quality of the software that causes the lack of donations.

Of course I am biased in this, but I think one should be careful spreading the attitude that paying for software is foolish. Developers, in particular those who develop free software should be encouraged, and not taken for granted.

... so, now I have said that. Now I am nice again. :)


i agree with you if i had the $ right now i would get it in a heart beat that was why i am only looking for the formula that was in that book from radio shack or if some one had dealt with this driver before .people spend a lot of time developing software and thy should get something for there time .
 
A couple thoughts- it's really good to do your own math for simple box design because it will help your understanding of the process. There's some great software out there (and some not-so-great), but you can't trust the results of any of it unless you understand what the inputs really mean. When you get to more complex stuff and want to rely on software done by somebody who's already been down that road, those previously learned basics will still be valuable.

On donations, so much free/share/donate/trial ware is in a very narrow niche. I've downloaded an awful lot of software just out of curiosity, certainly Svante's too. I have a look, and move on. Since I'm typically not building anything at the time, I don't donate. My guess is 99% of downloaders are in this mode, with very few actually putting the software to use on a project. Back in the DOS days of Madisounds BBS, I put up some speaker design software that had thousands of downloads. Out of all those downloads, I never heard anything much back. I thought of porting my stuff over to a nice free Windows app, but IMO the "market" is completely saturated, so why waste the time? IMO, this stuff has to be a labor of love and you have to try and please yourself, because if you wait for validation from others, it may be a long time coming.:whazzat:
 

EC8010

Ex-Moderator
2003-01-18 7:57 am
Near London. UK
Credit where it's due...

Svante said:
Well, I would disagree. It is true that there are nice people out there offering good software for free, but I would not say that it is foolish to pay something for their effort.

Hmmm, I should have expressed myself more clearly. What I should have said is that the equations for working out a small box design are so simple that a minute with a calculator will solve them and determine the necessary box volume. Therefore, why pay money when one minute's effort will do the job? I'm annoyed that there are plenty of internet hucksters who try to extract payment for nothing (people selling Acrobat reader and semiconductor data sheets spring to mind). Conversely, there are some super bits of freeware on the web such as your "Edge", and if ever we should meet up, I'd be delighted to buy a beer, two even!
 
Re: Credit where it's due...

Conrad Hoffman said:
A couple thoughts- it's really good to do your own math for simple box design because it will help your understanding of the process. There's some great software out there (and some not-so-great), but you can't trust the results of any of it unless you understand what the inputs really mean. When you get to more complex stuff and want to rely on software done by somebody who's already been down that road, those previously learned basics will still be valuable.

Yes, indeed, I totally agree. Then again, I might be biased again since my main income is teaching stuff like this. :)

Conrad Hoffman said:

On donations, so much free/share/donate/trial ware is in a very narrow niche. I've downloaded an awful lot of software just out of curiosity, certainly Svante's too. I have a look, and move on. Since I'm typically not building anything at the time, I don't donate. My guess is 99% of downloaders are in this mode, with very few actually putting the software to use on a project. Back in the DOS days of Madisounds BBS, I put up some speaker design software that had thousands of downloads. Out of all those downloads, I never heard anything much back. I thought of porting my stuff over to a nice free Windows app, but IMO the "market" is completely saturated, so why waste the time? IMO, this stuff has to be a labor of love and you have to try and please yourself, because if you wait for validation from others, it may be a long time coming.:whazzat:

Yes I do that too. I realize that only a small percentage of the downloads corresponds to actual usage. However, I refuse to believe that of the more than 10000 unique IP downloads of Edge, only 2 persons have really had good use of it.

Then again, I must confess that I also download software without donating.

I dunno, I am probably overreacting, but I think it is a pity that loudspeaker design software has to be written by idealists.

EC8010 said:


Hmmm, I should have expressed myself more clearly. What I should have said is that the equations for working out a small box design are so simple that a minute with a calculator will solve them and determine the necessary box volume. Therefore, why pay money when one minute's effort will do the job? I'm annoyed that there are plenty of internet hucksters who try to extract payment for nothing (people selling Acrobat reader and semiconductor data sheets spring to mind). Conversely, there are some super bits of freeware on the web such as your "Edge", and if ever we should meet up, I'd be delighted to buy a beer, two even!

:) Thanks, sorry if I had a harsh tone... I'd have to go for a coke or something though, beer is not my cup of tea. :D
 
Freeware is great. My hat is off to all those that have posted useful applications for our hobby, however, there is a space for well coded commercial apps as well. I started off doing speaker design with a calculator, and then moved onto free SW, but recently shelled out for Soundeasy, simply because I wanted to do things with a program that was powerful, well supported, and did things better than any free program ever could. I'm not saying you can't design good speakers with free SW, you can, but when you get to a certain level, the right program can save time, money, and stress.

Support all programmers, whether paid or free, because without them life would be so much harder...