Finding the volume of a driver

wigginjs · 6th April 2004, 10:44 PM

I'm designing a new sub for my HT involving a Dayton Titanic MKIII 12" woofer. I'm curious, whats the best way to find the volume of a particular driver? Does the manufacturer ever provide this information? I need to know because I'm going to add this amount, as well as the volume of the port tubes and bracing so I will know the exact dimensions of the enclosure I need to build.

Keld · 6th April 2004, 11:34 PM

this is the answer I got when writning to Peerless asking for the volume of a 12"XLS:

Quote:

" SNIP
We do not have the volumes of the drivers, I think that you mean how much
volume the drivers take in the box?

But in real life, you can count on the following:

1. The driver magnetsystem takes a lot of volume, it can be calculated very
easily as a cylinder.

2. The cone takes some volume also, but you have also cut a hole in the
baffle for the driver? The hole in the baffle makes the volume bigger and
the cone takes some of the volume back. This means if you neglect the hole
in the baffle and neglect the cone, the error you make is small.

This means, calculate the volume of the magnetsystem and neglect the cone.
SNIP

I have even drawn a pic of the cone: volume :http://www.diyaudio.com/forums/showt...255#post109255

moving_electron · 6th April 2004, 11:46 PM

Quote:

Originally posted by m0tion
I'm designing a new sub for my HT involving a Dayton Titanic MKIII 12" woofer. I'm curious, whats the best way to find the volume of a particular driver?

Find a cardboard box that the driver fits in such as the one it shipped in. Calculate the volume of the box from it's dimensions.

Put a plastic bag around the driver and put the driver upsidedown in the box. Pour in rice until the box is full. Measure the volume of the rice. Subtract this from the box volume to get the driver volume. (Small error due to some of the speaker being in the baffel.)

Keld · 7th April 2004, 12:10 AM

Quote:

Originally posted by moving_electron

Find a cardboard box that the driver fits in such as the one it shipped in. Calculate the volume of the box from it's dimensions.

Put a plastic bag around the driver and put the driver upsidedown in the box. Pour in rice until the box is full. Measure the volume of the rice. Subtract this from the box volume to get the driver volume. (Small error due to some of the speaker being in the baffel.)

the error is the same as the volume of the hole in baffle in the final box.

wigginjs · 7th April 2004, 01:31 PM

Damn, I was hoping you guys would know some sort of quick trick =). It seems like this would be information that should be provided by the manufacturer. Thanks for the help.

markp · 7th April 2004, 01:46 PM

Some do post the volume displaced by the driver, not the cone displacement but the volume occupied by the driver.

mwmkravchenko · 7th April 2004, 03:06 PM

Search for a program called the driver parameter calculator DPC I think it has a routine for the calculation of the volume of a driver that is pretty accurate.

http://www.diysubwoofers.org/audiolinks.htm

It's about 2/3rds the way down

Mark

moving_electron · 7th April 2004, 03:11 PM

Well, it looks like the fastest way to get a number that is close to the actual volume is to use the suggestion in one of the posts above to calculate the volume by calculating it is a combination of cylinders.

The volume of the cylinder = pi * r * r* h where
pi = 3.14159
r = radius (not diameter!) of the circle that forms the base
h = hieght of the cylinder

Calculate the magnet portion which looks to be pretty much a cylinder.

Calculate the basket portion that will actually be in the subwoofer box when it is mounted. Calculate it as a cylinder and then take off some percent (maybe 35%?) since it really is a more of a cone with a lopped of top shape.

Add the two together and you have a pretty good estimate.

kelticwizard · 7th April 2004, 10:25 PM

In this thread, I did a rough estimate of the occupied volume for a Peerless 12" XLS. It came to 2.5 liters.
XLS-Subwoofer question: Two passive radiators instead of one

So call it three liters and you can't be much off.

Unless you get to 10% or so of the entire box volume, there is virtually negligible effect on the response. That rough estimate simply cannot be off by much. In fact, a lot of people get good results just ignoring the volume of the speaker altogether.

sreten · 7th April 2004, 10:31 PM

The answer you got from Peerless is entirely
sensible. Unless you have a 3" thick baffle.

sreten.

6th April 2004, 10:44 PM	#1
wigginjs diyAudio Member Join Date: Dec 2003 Location: Columbia, SC	Finding the volume of a driver I'm designing a new sub for my HT involving a Dayton Titanic MKIII 12" woofer. I'm curious, whats the best way to find the volume of a particular driver? Does the manufacturer ever provide this information? I need to know because I'm going to add this amount, as well as the volume of the port tubes and bracing so I will know the exact dimensions of the enclosure I need to build.

7th April 2004, 01:46 PM	#6
markp diyAudio Member Join Date: Oct 2003 Location: L.A., CA	Some do post the volume displaced by the driver, not the cone displacement but the volume occupied by the driver. __________________ If it sounds good... it is good!

7th April 2004, 03:06 PM	#7
mwmkravchenko diyAudio Member Join Date: Jan 2002 Location: Perth Canada	Try this Search for a program called the driver parameter calculator DPC I think it has a routine for the calculation of the volume of a driver that is pretty accurate. http://www.diysubwoofers.org/audiolinks.htm It's about 2/3rds the way down Mark __________________ Mark

7th April 2004, 10:25 PM	#9
kelticwizard diyAudio Member Join Date: Sep 2001 Location: Connecticut, The Nutmeg State	In this thread, I did a rough estimate of the occupied volume for a Peerless 12" XLS. It came to 2.5 liters. XLS-Subwoofer question: Two passive radiators instead of one So call it three liters and you can't be much off. Unless you get to 10% or so of the entire box volume, there is virtually negligible effect on the response. That rough estimate simply cannot be off by much. In fact, a lot of people get good results just ignoring the volume of the speaker altogether. __________________ "A friend will help you move. A really good friend will help you move a body." -Anonymous

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7th April 2004, 01:31 PM	#5
wigginjs diyAudio Member Join Date: Dec 2003 Location: Columbia, SC	Damn, I was hoping you guys would know some sort of quick trick =). It seems like this would be information that should be provided by the manufacturer. Thanks for the help.

7th April 2004, 03:11 PM	#8
moving_electron diyAudio Member Join Date: Jan 2004 Location: Where the rain does fall but the trees grow tall	Well, it looks like the fastest way to get a number that is close to the actual volume is to use the suggestion in one of the posts above to calculate the volume by calculating it is a combination of cylinders. The volume of the cylinder = pi * r * r* h where pi = 3.14159 r = radius (not diameter!) of the circle that forms the base h = hieght of the cylinder Calculate the magnet portion which looks to be pretty much a cylinder. Calculate the basket portion that will actually be in the subwoofer box when it is mounted. Calculate it as a cylinder and then take off some percent (maybe 35%?) since it really is a more of a cone with a lopped of top shape. Add the two together and you have a pretty good estimate.

7th April 2004, 10:31 PM	#10
sreten diyAudio Member Join Date: Nov 2003 Location: Brighton UK	The answer you got from Peerless is entirely sensible. Unless you have a 3" thick baffle. sreten.

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