Home Theater Forum and Systems banner
1 - 11 of 11 Posts

·
Registered
Joined
·
1,363 Posts
Discussion Starter · #1 · (Edited)
I've been trying to model the Fi Q 12's recently. But, I find that when I enter the Mms and Cms specs, the driver's resonance frequency comes out to be 10.XXhz, when it says 33.9hz on Fi's website.
I changed the Mms to 25.3 grams, and it changes the frequency to 33.92hz, very close to the stated specs. But, then the Vas is very far off. 285.53 liters compared to 28.3 liters on their website. What am I doing wrong?

Link to Fi Q subs here
 

·
Elite Shackster
Joined
·
7,142 Posts
It sounds like it could be a misplaced decimal point. Look at the values assigned to your input parameters and ensure they match the ones on the website. So for example, if you look next to the mms input box you should see either 'g' for grams, of 'kg' for kilograms. If this is different to what is indicated in the driver specs on the website, then you could end up with values that come out at say 235 instead of 23.5 etc etc.

You can alter the values in the WinISD input box by putting your cursor over them and altering them.

Also, when you input information, some values are auto calculated and you should leave these. Its quite common for them not to match the stated figures exactly, but so long as they are close, its not a problem. When you consider each driver will vary slightly anyway, kinda like each new car will have a slightly different actual horse power produced from its engine than what is stated by the manufacturer, then figures that are marginally off are fine.
 

·
Registered
Joined
·
1,363 Posts
Discussion Starter · #5 ·
Ok, I figured out what was wrong. For Cms (like Mike stated), it needs to be changed to 0.087mm/N. Its just 0.87mm/N on their website. I had been trying to change different specs around (a lot of them gave me crazy results and errors :D), and I tried Cms right before I saw Mike's post.

A9X, I've looked at that thread in the past, and made sure that I memorized how to input the specs in the right order, as is shown in that thread. :T. Thanks for the link to.

Dan, I tried putting in the specs for the driver about 10 times. At least I got consistent results :bigsmile: , but they were just wrong results. I double checked every time that every unit of measurement was correct before proceeding with entering the specs.


Thanks for the replies everyone. :T
 

·
Registered
Joined
·
2,625 Posts
Glad you found the answer. I usually put in the Fs and mechanical parameters first. I've found it usually calculates the electrical parameters correctly after that. :T
 

·
Registered
Joined
·
1,363 Posts
Discussion Starter · #8 ·
Glad it worked for you in the end.
I use Unibox because I find WinISD to be a pain.

Once you learn how to use WinISD, its very easy. I can enter any driver's specs in the right order now, this was about the second one that has only given me problems.

Funny thing is 2 Q 12's in a 3 cu.ft box with 2kw model slightly better than 2 BTL 12's in a 1.5 cu.ft box with 4kw of power.
 

·
Elite Shackster
Joined
·
7,142 Posts
Once you learn how to use WinISD, its very easy. I can enter any driver's specs in the right order now, this was about the second one that has only given me problems.
I think in this case, using WinISD was probably an advantage. It was a website error causing the issue, which the program spotted. If Unibox would have just used the wrong parameter without questioning it, couldnt it have thrown the model out a bit?

:ponder: Perhaps someone can test this and see
 

·
Registered
Joined
·
790 Posts
Once you learn how to use WinISD, its very easy.
I know how to use it I just don't find it user friendly or intuitive.

I think in this case, using WinISD was probably an advantage. It was a website error causing the issue, which the program spotted. If Unibox would have just used the wrong parameter without questioning it, couldnt it have thrown the model out a bit?

:ponder: Perhaps someone can test this and see
For sure the model would have been out but you don't enter Cms in Unibox, it calcs it for you from the other parameters entered.
 

·
Elite Shackster
Joined
·
7,142 Posts
I know how to use it I just don't find it user friendly or intuitive.
Funny how we are isnt it. I didnt like the look of Unibox so didnt even try with it. I really like WinISD, I find it very user friendly and intuitive :huh:
 
1 - 11 of 11 Posts
Top