MJK worksheets vs port location

johngalt47 · 9th March 2009, 11:22 AM

I was working with the ML-TQWT worksheet and something just occurred to me.

For the sake of argument, let's say that the driver is 25% from the "top" of the box and the center of the port opening is 4 inches (100mm) from the "bottom" of the box.

Also for the sake of argument let's say that the length of the port tube causes a 90 degree bend in the tube. Let's make the tube long enough so the the tube opening on the inside of the box is near the driver.

Would this mean that the driver is now acoustically at the "bottom" of the box instead of the top? Or does it not matter at all where the end of the tube is inside the box?

Scottmoose · 9th March 2009, 11:33 AM

The initial part of the worksheets assume you are defining the internal location of the vent.

johngalt47 · 9th March 2009, 12:32 PM

So... if you needed a long tube where would you locate the end?

MJK · 9th March 2009, 12:35 PM

The driver is still at the 25% location. If the port tube extends up almost to the driver then the port tube is also close to the 25% location. The entrance to the port tube is the important variable in the model of the air in the box, the first part of the worksheet. In the second part of the worksheet, the port tube exit is the important variable.

Hope that helps,

9th March 2009, 11:22 AM	#1
johngalt47 diyAudio Member Join Date: Mar 2004 Location: Texas	MJK worksheets vs port location I was working with the ML-TQWT worksheet and something just occurred to me. For the sake of argument, let's say that the driver is 25% from the "top" of the box and the center of the port opening is 4 inches (100mm) from the "bottom" of the box. Also for the sake of argument let's say that the length of the port tube causes a 90 degree bend in the tube. Let's make the tube long enough so the the tube opening on the inside of the box is near the driver. Would this mean that the driver is now acoustically at the "bottom" of the box instead of the top? Or does it not matter at all where the end of the tube is inside the box? __________________ Any technology sufficiently advanced is indistinguishable from magic

9th March 2009, 12:32 PM	#3
johngalt47 diyAudio Member Join Date: Mar 2004 Location: Texas	So... if you needed a long tube where would you locate the end? __________________ Any technology sufficiently advanced is indistinguishable from magic

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9th March 2009, 11:33 AM	#2
Scottmoose diyAudio Member Join Date: Mar 2005 Location: UK	The initial part of the worksheets assume you are defining the internal location of the vent.

9th March 2009, 12:35 PM	#4
MJK Account disabled at member's request Join Date: Feb 2002 Location: Clifton Park, NY	The driver is still at the 25% location. If the port tube extends up almost to the driver then the port tube is also close to the 25% location. The entrance to the port tube is the important variable in the model of the air in the box, the first part of the worksheet. In the second part of the worksheet, the port tube exit is the important variable. Hope that helps,

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