No issues. Had drivers out to upgrade crossovers and absorbent material.What made you do it now? Were they having "issues"?
Didn't expect to be opening the cabinets again any time soon, so inverted the drivers for posterity.
I'm talking small, light paper cones and competent spider assemblies, so inversion was almost certainly unnecessary and overly obsessive!
Perhaps, plasnu, this will help your peace of mind, or maybe you are wishing you'd never come across this thread......
We are really discussing two aspects here - prevention and cure.It did the trick, for a while
What evidence is there that regular inversion will prevent a suspension from sagging?
Who can testify that inversion has permanently reversed the effect of an already sagging suspension?
IME WRT storing drivers horizontally, flipping them over eventually makes them sag a similar amount in the other direction, or in at least the case with some NOS Altec MI drivers will only sag till it bottoms on the back plate when face up whereas in the other direction will sag completely out of the gap.
Fortunately, setting them out in the Ga. summer heat drops them back in without misalignment every year since circa '72 IIRC, so gotta respect Altec quality before its downfall.
GM
Fortunately, setting them out in the Ga. summer heat drops them back in without misalignment every year since circa '72 IIRC, so gotta respect Altec quality before its downfall.
GM
Ha! I remember when Jason Kidd got traded to the Mavericks he said this in a serious manner. “My job is to turn this franchise around 360 degrees.” They did eventually win a championship.I go one further than that. I rotate them a full 360º.
That is precisely the issue!Real issue is:
Do you want to risk being proven wrong
Yes. Once the cone suspension has weakened, inverting the driver can only give temporary respite.
A common problem is the spider surround becoming detached from the basket. Always a good place to look if voice coil rubbing is encountered.
The spider does the majority of the job of centering the voice coil, the cone surround is secondary in this task.
A common problem is the spider surround becoming detached from the basket. Always a good place to look if voice coil rubbing is encountered.
The spider does the majority of the job of centering the voice coil, the cone surround is secondary in this task.
I do rotate the stored ones every half year, but 90 degrees at a time.
Old non-laminated ribbons should be stored upright in order not to sag.
I discussed the topic both with AES member and a associate professor in electro acoustics back in the day, a driver that plays daily or frequently centers itself and rotation is not needed. Even for 250 g Mms bass drivers.
Another issue is storing drivers facing down. Strangely, drivers tend to sag more inwards than outwards. I have some 10 and 12 car drivers that I store only facing down and they are perfect. I also cured a pair of Pioneer 2510A that were both rubbing and sagged inwards by simply storing them face down for an extended period.
Old non-laminated ribbons should be stored upright in order not to sag.
I discussed the topic both with AES member and a associate professor in electro acoustics back in the day, a driver that plays daily or frequently centers itself and rotation is not needed. Even for 250 g Mms bass drivers.
Another issue is storing drivers facing down. Strangely, drivers tend to sag more inwards than outwards. I have some 10 and 12 car drivers that I store only facing down and they are perfect. I also cured a pair of Pioneer 2510A that were both rubbing and sagged inwards by simply storing them face down for an extended period.
Several distinct themes are emerging in this discussion.
These themes being the effect of:
- vertical orientation
- horizontal orientation
- daily use
- long term storage.
Indeed, otherwise you are fatiguing one and the same static bearing parts of the suspension. And the weakened region gets narrowed and smaller with every switch of direction.
Rotating makes for circular type of end (voice coil) movement involving the whole suspension.
The following comments assume a vertically mounted driver:
The spider is usually made from woven fabric which is treated with a phenolic resin to stiffen the spider and provide the desired restoring forces required in the vertical direction.
The corrugations allow the necessary horizontal motion of the voice coil.
I can see that, over time, the corrugations may become squashed at the bottom of the spider and stretched at the top, so that occasional 90 degree rotation may be desirable.
The spider is usually made from woven fabric which is treated with a phenolic resin to stiffen the spider and provide the desired restoring forces required in the vertical direction.
The corrugations allow the necessary horizontal motion of the voice coil.
I can see that, over time, the corrugations may become squashed at the bottom of the spider and stretched at the top, so that occasional 90 degree rotation may be desirable.
Attachments
The BMS engineer said the coil is held in proper position by amplifier when music is played, with no need to compensate for gravity. Said ideally music would be on 24/7 haha
I see this rotation topic has gathered a number of opinions "in rotational opposition to each other" Lol.
I do think flipping heavy horizontally mounted drivers periodically is wise. Pro-sound guys discuss the need, especially in humid areas.
But I'm talking mainly big sub drivers. Hey there's a reason a lot of them come with double spiders. I might rotate or flip tapped horns too...anytime the inclination is towards horiz, and gravity takes more toll.
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