4350 transport advice

[Goldjazz]

Well I've taken the plunge to get a pair of these big boys. However I'm basically getting them freighted from one side of Australia to the other by road (2500 miles).

So Ive heard some people say speaker cabinets should be transported lying on their backs so that the cone generally moves in and out with bumps in the road, to minimise the coil rubbing. These 4350s have the foam gone on the woofers so the cones may be even more free to bounce around than usual.

Just wondering what people think about transporting on the backs like this.

Thanks.

[johnlcnm]

I transported my 4333's on their backs. Short the low frequency input terminals. I also taped the ports.

[SEAWOLF97]

So Ive heard some people say speaker cabinets should be transported lying on their backs so that the cone generally moves in and out with bumps in the road, to minimise the coil rubbing. These 4350s have the foam gone on the woofers so the cones may be even more free to bounce around than usual.

Just wondering what people think about transporting on the backs like this.

Thanks.

I'm NOT an expert on this , but think that your "on their backs" idea makes good sense tho I doubt that JBL originally shipped them that way.

Also think that when you receive them, rotating the LF drivers 180 degrees seems prudent too.

[Goldjazz]

thanks All. Turns out they be transported by Rail rather than road. Not sure if this is better or worse. I've actually opted not to put them back down at this stage. Will see how we go.

[Earl K]

thanks All. Turns out they be transported by Rail rather than road. Not sure if this is better or worse. I've actually opted not to put them back down at this stage. Will see how we go.

If you want to avoid the possibility of shifted magnets then have all the drivers removed, boxed in foam and placed on their own pallet ( look into some form of travel insurance ).

The glue in these older transducers holding the magnets in place was never meant to last forever. For most, a shifted magnet means the transducer becomes a door stop.

If the woofer & 2202's are ferrite magnet types then it's time to get rid of the inner foam filter that has ( or is about to ) crumble and gum up the coil in the gap.

Here's a pic of the offending foam filter;

http://www.audioheritage.org/photopost/data//500/2235h_x4_10015979762.jpg

:)

[Goldjazz]

If you want to avoid the possibility of shifted magnets then have all the drivers removed, boxed in foam and placed on their own pallet ( look into some form of travel insurance ).

The glue in these older transducers holding the magnets in place was never meant to last forever. For most, a shifted magnet means the transducer becomes a door stop.

If the woofer & 2202's are ferrite magnet types then it's time to get rid of the inner foam filter that has ( or is about to ) crumble and gum up the coil in the gap.

Here's a pic of the offending foam filter;

http://www.audioheritage.org/photopost/data//500/2235h_x4_10015979762.jpg

:)
Thanks interesting. No these one are Alnico. was the foam issue only in the midbass driver? I have ferrite woofers in my 4343's did they have this issue too? Thanks

[Earl K]

Ahh ( Alnico ),

Edgewise is the LHFer with the final authority here, but I believe the alnico versions of the woofer ( in your 4350 ) have motors that are fully bolted together ( therefore better resisting shifting magnet problems.

:)

[Goldjazz]

Ahh ( Alnico ),

Edgewise is the LHFer with the final authority here, but I believe the alnico versions of the woofer ( in your 4350 ) have motors that are fully bolted together ( therefore better resisting shifting magnet problems.

:)

Ok thanks.

[RMC]

Hi Goldjazz,

This should be of interest to you and others, plus confirms what Johnlcnm wrote in post # 2 about shorting LF input terminals. It seems to be what JBL actually suggests to do when speaker transport is involved:

"Loudspeaker cones can bounce around quite a bit during transport, and cone damage can sometimes occur because of this. However, shorting the voice coils during shipment will tend to damp out cone movement, lessening the possibility of damage." (note 1)

A picture is attached showing how JBL does it with 1/4" input connectors (first example), but you can adapt it to you particular connector situation.

Having no woofer surrounds in place to hold the cones makes your shipment even more fragile I guess. Good luck. Regards,

Richard

Note 1: JBL Enclosure Information Manual, 1979, P. 21


83197

[Goldjazz]

Hi Goldjazz,

This should be of interest to you and others, plus confirms what Johnlcnm wrote in post # 2 about shorting LF input terminals. It seems to be what JBL actually suggests to do when speaker transport is involved:

"Loudspeaker cones can bounce around quite a bit during transport, and cone damage can sometimes occur because of this. However, shorting the voice coils during shipment will tend to damp out cone movement, lessening the possibility of damage." (note 1)

A picture is attached showing how JBL does it with 1/4" input connectors (first example), but you can adapt it to you particular connector situation.

Having no woofer surrounds in place to hold the cones makes your shipment even more fragile I guess. Good luck. Regards,

Richard

Note 1: JBL Enclosure Information Manual, 1979, P. 21


83197

This is a pretty neat solution, thanks. So I guess I would need to get the seller to remove the woofers, unplug the wires coming from the crossover and place a short wire between the red and black terminals of each woofer?

[kelossus]

Did you buy the pair on the Goldcoast? I have been eyeing them off on Gumtree for awhile.

[Goldjazz]

Did you buy the pair on the Goldcoast? I have been eyeing them off on Gumtree for awhile.

No, didnt see those ones. Pull the trigger, join the club :)

[RMC]

Hi Goldjazz,

Yes short the cone driver inputs.

But shorting isn't fool proof: "...will tend to damp out cone movement, lessening the possibility of damage."

Other than shorting the inputs, what concerns me most is the lack of surrounds to hold the cones from moving left, right, up or down when things get bumpy. And they likely will.

I'd tend to say also have some "padding" material put between back of cone and driver frame legs to minimize movement. That should not be forced in nor push on the cone but just hold it there and stop it from bouncing as the ride gets tough, as it may well do on a 2,500 miles trip including handling such as loading and unloading....

For example, try to have seller to tie-wrap pieces of soft foam on driver frame legs just behind the cone edge so the soft foams slighly touch the cone, therefore preventing it from moving in all directions. Trying to protect the the original driver cones as much as possible is nice because then you "only" have a refoam job to do, not additional repairs caused by shipping...

By analogy, if these boxes were my pants, I'd try to secure them with THE BELT AND THE SUSPENDERS for shipment, to make sure the treasure isn't damaged... Better be safe than sorry. Regards,

Richard

[Goldjazz]

Hi Goldjazz,

Yes short the cone driver inputs.

But shorting isn't fool proof: "...will tend to damp out cone movement, lessening the possibility of damage."

Other than shorting the inputs, what concerns me most is the lack of surrounds to hold the cones from moving left, right, up or down when things get bumpy. And they likely will.

I'd tend to say also have some "padding" material put between back of cone and driver frame legs to minimize movement. That should not be forced in nor push on the cone but just hold it there and stop it from bouncing as the ride gets tough, as it may well do on a 2,500 miles trip including handling such as loading and unloading....

For example, try to have seller to tie-wrap pieces of soft foam on driver frame legs just behind the cone edge so the soft foams slighly touch the cone, therefore preventing it from moving in all directions. Trying to protect the the original driver cones as much as possible is nice because then you "only" have a refoam job to do, not additional repairs caused by shipping...

By analogy, if these boxes were my pants, I'd try to secure them with THE BELT AND THE SUSPENDERS for shipment, to make sure the treasure isn't damaged... Better be safe than sorry. Regards,

Richard

Thanks Richard. Agree with the belt and braces approach. It's just one of those issues where the seller isn't technically competent and I'm concerned If I ask to much of him he'll spit the dummy. a fine line I need to walk here, but I've paid a fair bit for them so hopefully he'll be willing to cooperate. The other idea is to get him to remove the midbass and woofer drivers and take them to a pack and send place where they can be packed more carefully and air freighted for a less bumpy journey. But It's just a tradeoff of piece of mind and reducing repair risk vs shipping costs.