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.
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.
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.
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.
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.
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.
the box face and the driver face are parallel to each other.
I thought vertical was the accepted definition, but maybe there is no universal descriptor.
Do we need to specify which we intend every time we refer to this?
Precisely, so hence my confusion. If the baffle is vertical why then do you call a woofer mounted to it to be horizontal?
down firing
So, after all that, one person says a down firing sub will sag more over time. Is this based on experience?
So, after all that, one person says a down firing sub will sag more over time. Is this based on experience?
Unless the magnet is alnico then it will not sag any significant amount. I built a downfiring subwoofer nearly 13 years ago that's still just fine.
Best Regards,
TerryO
"How far will it continue to sag beyond the initial .5mm? It will just keep sagging more and more until the coil is just hanging out of the gap? "
Until the spider takes a set and then it will oilcan after that.
I've had new woofers in the shipping container be trashed after the spider took a set. Sometimes you can soak the spider with acetone, run some DC in to hold it the opposite direction, and let the solvent evaporate. Sometimes not.
Sometimes you have to rotate vertical mounted drivers 180° every so often (a year or two) to combat sag. I'm not inclined to mount drivers in the horizontal plane at all.
Until the spider takes a set and then it will oilcan after that.
I've had new woofers in the shipping container be trashed after the spider took a set. Sometimes you can soak the spider with acetone, run some DC in to hold it the opposite direction, and let the solvent evaporate. Sometimes not.
Sometimes you have to rotate vertical mounted drivers 180° every so often (a year or two) to combat sag. I'm not inclined to mount drivers in the horizontal plane at all.
You will find asking such questions gets you no where.
You will have people swear up and down that every driver will sag to the floor, and another set that talk about how they have had drivers inverted for years with no problems.
What should you take from this?
Some drivers will be fine, and others will not. I have had drivers last while downfiring, and others that started noticeable over-sagging after a couple years.
The drivers that I have had that continued to droop were not effected by rotation. If you flipped it over it just sagged the other way the same amount. Spider construction, and materials play a part here.
In the end, there is no single correct answer. Your best bet is to just ask others with the same drivers what their experiences with that driver model were/are. You may also want to ask about the environment the driver was used/stored in.
You will have people swear up and down that every driver will sag to the floor, and another set that talk about how they have had drivers inverted for years with no problems.
What should you take from this?
Some drivers will be fine, and others will not. I have had drivers last while downfiring, and others that started noticeable over-sagging after a couple years.
The drivers that I have had that continued to droop were not effected by rotation. If you flipped it over it just sagged the other way the same amount. Spider construction, and materials play a part here.
In the end, there is no single correct answer. Your best bet is to just ask others with the same drivers what their experiences with that driver model were/are. You may also want to ask about the environment the driver was used/stored in.
- Status
- This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.