Driver sag

Studley · 5th January 2011, 08:25 PM

I have seen the opinion expressed that it is not a good idea to mount a LF driver horizontally (i.e. so it is firing downwards) because over time gravity causes the cone to sag. I would be interested to hear whether this view is widely accepted or whether it is open to dispute. I'm talking about a 15" driver BTW.

AndrewT · 5th January 2011, 08:56 PM

Hi,
any driver cone will sag instantly when you rotate it to the vertical direction.
The sag may (/will) get worse as time goes on.

Even in the horizontal position the cone sags and uses up clearance of voice coil to magnetic pole.
Rotate the driver every other year to keep the VC near the middle of the magnetic gap.

Studley · 5th January 2011, 10:32 PM

Andrew
Your comment re rotation makes me wonder if we are talking at cross purposes. Just to make sure, when I say horizontal I mean with the cone facing straight down (from a ceiling). In that orientation rotating will not change anything as far as I can see.

BTW I have now done a sag calculation as shown on the Adire website and the driver is well below the suggested 5% limit, so I'm feeling happier.

AndrewT · 6th January 2011, 08:57 AM

glad you found the Adire calculation.
Yes, I was talking about the same thing, vertical mounting = facing the floor or ceiling.
Horizontal mounting = normal = facing the wall or listener.

djk · 7th January 2011, 01:25 AM

"BTW I have now done a sag calculation as shown on the Adire website and the driver is well below the suggested 5% limit, so I'm feeling happier. "

It will still sag over time.

Cal Weldon · 10th January 2011, 12:08 AM

Quote:

Originally Posted by AndrewT

vertical mounting = facing the floor or ceiling.
Horizontal mounting = normal = facing the wall or listener.

I would find that confusing and have always referred to it the other way around.

Charles Darwin · 10th January 2011, 06:16 AM

Quote:

Originally Posted by Cal Weldon

I would find that confusing and have always referred to it the other way around.

I would agree.

djk · 10th January 2011, 08:01 AM

I would prefer to use vertical for facing wall or listener.

pinkmouse · 10th January 2011, 08:23 AM

Quote:

Originally Posted by Cal Weldon

I would find that confusing and have always referred to it the other way around.

Just to add confusion, in the PA world, it has yet another meaning, vertical being the standard way we look at a rectangular box, i.e. tweeter on the top, with mid and bass below, facing the listener, and horizontal, with the box on it's long side, drivers side by side, still facing forwards.

Cal Weldon · 10th January 2011, 01:42 PM

Ya PM, I don't think that's confusing, as you're talking the box versus the driver so no problem there.

5th January 2011, 08:25 PM	#1
Studley diyAudio Member Join Date: Jan 2005 Location: West Riding of Yorkshire, England	Driver sag I have seen the opinion expressed that it is not a good idea to mount a LF driver horizontally (i.e. so it is firing downwards) because over time gravity causes the cone to sag. I would be interested to hear whether this view is widely accepted or whether it is open to dispute. I'm talking about a 15" driver BTW.

5th January 2011, 08:56 PM	#2
AndrewT diyAudio Member Join Date: Jul 2004 Location: Scottish Borders	Hi, any driver cone will sag instantly when you rotate it to the vertical direction. The sag may (/will) get worse as time goes on. Even in the horizontal position the cone sags and uses up clearance of voice coil to magnetic pole. Rotate the driver every other year to keep the VC near the middle of the magnetic gap. __________________ regards Andrew T.

6th January 2011, 08:57 AM	#4
AndrewT diyAudio Member Join Date: Jul 2004 Location: Scottish Borders	glad you found the Adire calculation. Yes, I was talking about the same thing, vertical mounting = facing the floor or ceiling. Horizontal mounting = normal = facing the wall or listener. __________________ regards Andrew T.

7th January 2011, 01:25 AM	#5
djk diyAudio Member Join Date: Feb 2001 Location: USA	"BTW I have now done a sag calculation as shown on the Adire website and the driver is well below the suggested 5% limit, so I'm feeling happier. " It will still sag over time. __________________ Candidates for the Darwin Award should not read this author.

10th January 2011, 08:01 AM	#8
djk diyAudio Member Join Date: Feb 2001 Location: USA	I would prefer to use vertical for facing wall or listener. __________________ Candidates for the Darwin Award should not read this author.


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5th January 2011, 10:32 PM	#3
Studley diyAudio Member Join Date: Jan 2005 Location: West Riding of Yorkshire, England	Andrew Your comment re rotation makes me wonder if we are talking at cross purposes. Just to make sure, when I say horizontal I mean with the cone facing straight down (from a ceiling). In that orientation rotating will not change anything as far as I can see. BTW I have now done a sag calculation as shown on the Adire website and the driver is well below the suggested 5% limit, so I'm feeling happier.

10th January 2011, 01:42 PM	#10
Cal Weldon Speakerholic diyAudio Moderator Join Date: Jan 2004 Location: British Columbia	Ya PM, I don't think that's confusing, as you're talking the box versus the driver so no problem there. __________________ Next stop: Margaritaville Some of Cal's stuff \| Cal Weldon Consulting

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