How to adjust the tension of bass ribbons?

[Jeff Apogee]

Dear Apogee lovers,
I have a calipier sig and the right side the ribbon on the bass is rattling,vibrating.How do I tighten the tension so that it will not vibrate and rattle.
Thank you for your prompt responses

[Graz]

Hello Jeff, and welcome to the forum.

Regretfully - Apogee's suffer from an ageing failure mode called "buzz". This can be slight, and progress over either a long or shorter period of time. The main reason for this type of "buzz" is failure of the foams that are around the bass ribbon, sandwiched over and under the ribbon on the edge of the clamps - this foam is crucial in damping own the excessive vibration at the edge of the ribbons. PLEASE NOTE the slant and vertical clamp set (upper+lower) is stuck together, don't try to separate - you WILL kill the ribbon. Full explanation here;-

viewtopic.php?f=16&t=80

Whilst this is the reason for failure in almost all Apogee's sometimes there are other reasons for vibration. Here is a list;-

1) the upper horizontal clamps become overly loose and they can vibrate badly. SOLUTION for this kind of buzz is to make sure the clamps are in the correct adjustment. They should be TIGHT enough that they don't make a rattle noise, and LOOSE enough that they have a couple of mm of even (side to side being the same) lift motion, with the damping foam being under pressure. These clamps are not stuck together with glue. Check first.

2)the foam around the upper inside faces of the upper clamp set has deteriorated to the point the foam is not working. This is common, and the foam is easily replaced. Size = 6mm width x 3mm depth.

You may get lucky!

Where are you located Jeff?


Curious - Graz

[Jeff Apogee]

I have replaced the top and bottom clamp foam the screws are tight but the vibration comes from between the top clamp and the side clamp on the top left hand side of the right speaker.I tentsioned the Allen nut on the side and it's tight until I cannot tighten anymore but still have slack on the ribbons.But still vibrate.I live in Singapore actually Apogees are easy to change and repair only now stuck with the tensioning.Apogee used to have an instrument that can hear the different freq when is played and tensioned according to the freq being played that is so much easier but now by hand very difficult so is there a better easier way to do it?

[Graz]

Hello Jeff

Horizontal screws should not be tight - the clamp has to damp the edge resonances properly, it does this with a little motion...

If you have slack even after tightening the tuning bolts it sounds like your bass has been damaged at some point. Tuning is something that is done first of all when the bass is new - I have never heard "re-tuning" work. Older Apogee's can curve a bit effectively collapsing the tuning, all fixes to this involve repair at either by me or one of my Installers...

Take care - Graz

[Jeff Apogee]

Assuming that the bass is out if tune, how do I retune the bass ribbons?
the foam is new, what do u suggest I that I do at this point?
Thanks in advance. I have tried a quarter turn and the bass still have the vibration that I suspect is coming from the clamp/wood section.Now my concern is to tune it back to normal and find a solution to the vibration section.