Sanity check

planet10 · 7th March 2004, 06:33 AM

The ApexJr Super 8 has BL measured as 2.287 lb/A.

To use Martin's model i need BL in N/A

with 1 lb-ft = 1.356 Nm and 1m = 3.281 ft i'm figuring

1 ft/A = 4.45 N/A

ie this driver has a BL of 10.175 N/A ??

dave

kelticwizard · 7th March 2004, 06:41 AM

Got a link so I can look up the Thiele-Small parameters on that?

BoxModel will straighten this out.

kelticwizard · 7th March 2004, 06:59 AM

Here are your Thiele-Small parameters via BoxModel.

Bl is 9.18 Tm which I believe is the same as NA.

The numbers in the dark blue I wrote in, (I estimated 200 sq cm for the Sd), and the numbers in the light green underneath BoxModel calculates.

Neat, huh?

planet10 · 7th March 2004, 08:03 AM

Here are the measured parameters picked out of the pdf at ApexJr

dave

sreten · 7th March 2004, 10:31 AM

Quote:

Originally posted by planet10
The ApexJr Super 8 has BL measured as 2.287 lb/A.

To use Martin's model i need BL in N/A

with 1 lb-ft = 1.356 Nm and 1m = 3.281 ft i'm figuring

1 ft/A = 4.45 N/A

ie this driver has a BL of 10.175 N/A ??

dave

Should be just a case of converting pounds to newtons,

(1kg = 2.2 lbs = 9.8 newtons)

2.287 lb/A = 1.04 kg/A = 10.2 N/A.

sreten.

planet10 · 7th March 2004, 06:04 PM

Thanx Sreten... i've long lost handy access to all those convrsions in my head, and the others were the only quick factors i can find... now that i see 1 kg=9.8 N it all comes back... thanx for the forhead slapping moment

dave

sreten · 7th March 2004, 06:59 PM

You still got the right answer, near enough,

sreten.

joensd · 7th March 2004, 07:32 PM

Here´s a handy tool for converting quite a few units which I recently found on the net :

fireman · 7th March 2004, 08:08 PM

Hey Dave, what are you up to with this woofer ?

I meant to build something with this baby a few months ago. Time and money had me put the project to rest for a while. If I get the promotion I applied for, I guess it'll will have to wait 'til I move to my new workplace. Hopefully, I'll then have a real workshop where I can work on my speaker projects.

planet10 · 7th March 2004, 08:13 PM

Quote:

Originally posted by joensd
Here´s a handy tool for converting quite a few units which I recently found on the net :

Useful if you are running Windows....

I downloaded an OS X ap called Balance Pro... but didn't find the lbs > Netwtons conversion till just looking now.

http://www.MacDev.ca/

dave

7th March 2004, 06:33 AM	#1
planet10 frugal-phile(tm) diyAudio Moderator Join Date: Oct 2001 Location: Victoria, BC, NA, Sol III Blog Entries: 5	Sanity check The ApexJr Super 8 has BL measured as 2.287 lb/A. To use Martin's model i need BL in N/A with 1 lb-ft = 1.356 Nm and 1m = 3.281 ft i'm figuring 1 ft/A = 4.45 N/A ie this driver has a BL of 10.175 N/A ?? dave __________________ community sites t-linespeakers.org, frugal-horn.com, frugal-phile.com ........ commercial site planet10-HiFi p10-hifi forum here at diyA

7th March 2004, 06:41 AM	#2
kelticwizard diyAudio Member Join Date: Sep 2001 Location: Connecticut, The Nutmeg State	Got a link so I can look up the Thiele-Small parameters on that? BoxModel will straighten this out. __________________ "A friend will help you move. A really good friend will help you move a body." -Anonymous

7th March 2004, 06:04 PM	#6
planet10 frugal-phile(tm) diyAudio Moderator Join Date: Oct 2001 Location: Victoria, BC, NA, Sol III Blog Entries: 5	Thanx Sreten... i've long lost handy access to all those convrsions in my head, and the others were the only quick factors i can find... now that i see 1 kg=9.8 N it all comes back... thanx for the forhead slapping moment dave __________________ community sites t-linespeakers.org, frugal-horn.com, frugal-phile.com ........ commercial site planet10-HiFi p10-hifi forum here at diyA

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7th March 2004, 06:59 PM	#7
sreten diyAudio Member Join Date: Nov 2003 Location: Brighton UK	You still got the right answer, near enough, sreten.

7th March 2004, 08:08 PM	#9
fireman diyAudio Member Join Date: Dec 2003 Location: Trois-Rivières, Québec, Canada	Hey Dave, what are you up to with this woofer ? I meant to build something with this baby a few months ago. Time and money had me put the project to rest for a while. If I get the promotion I applied for, I guess it'll will have to wait 'til I move to my new workplace. Hopefully, I'll then have a real workshop where I can work on my speaker projects.

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