Warping frame on Diva's

[Zardoz]

Hi All,

I have a problem with my Diva's and wondered if anyone else has had this problem and if they have any other solutions or suggestions.

I purchase a pair of original Diva's (built 1988) a couple of years ago. Not long after I had them, the bottom of one woofer panel started sagging. More of a side to side sag rather than an up and down sag. This caused it to hit the backing and rattle and buzz. I determined that I could spread the bottom of the wooden frame a slight amount to stretch the panel back out and remove the rattle/buzz. So I cut a 1x1/2 piece of wood and pressed it into place below the clamp, which fixed the problem. Due to other buzzes though, I decided to have new ribbons installed and figured that would take care of it. This was done during the summer time.
After a year and a half with the new ribbons the same thing started again. Both times this occurred in winter, and my guess is that the drier air is a factor here. This time I used a steel threaded rod and a steel coupler to place below the bottom woofer "clamp". The one that stays loose, not tightened down, to spread the side frames. I have only applied a small bit of pressure with this spreader, but this has taken care of the problem again. I wonder if I should have something done to the frames, or if this fix will be fine when more humid weather comes back.

I have talked with Bill Thalmann about it and he thought this might be an ok fix. I and he would like to get the speakers to him to look at, but he is 5 hours away, and shipping would be very expensive, so if this fix is ok, I'll leave it as is.

Any thoughts would be great, especially from Jon or Graz.

Thanks,

[Al^]

I very much doult it's got to due with warping, the both side verticals of the bass are a good width each and are secured well, I would be more suspect of the tuning side ribbon rails, the other side lower is fixed solid and top clamp is secured to it. Not much chance of it shifting. Maybe the bottom clamp on the tuning side has come loose or cracked. Al

[Zardoz]

I understand what you are saying Al, but if that were the case, I won't think my fix would work. The ribbons wouldn't tighten up would they? They would just slide through the "loose" clamp, and they are not doing that. Also, when the speaker was laying flat on it's back on the work table, so that I could install the spreader, the sag in the ribbon could not be seen. This makes me think that the weight of the frame is straightening the warp back to flat in that position. It seems to me that the cross bar at the bottom of the speaker is the problem, and that it needs to be strengthened. Anyway, that's my guess for now.

Best,
Z

[apogee_admin]

Just a thought, is the cross brace on the stands putting the speaker under tension, maybe try removing the cross brace. Or if there is some slack in the holes - loosen the screws of the stand cross brace, push the ends of the speaker stands together at the back and have someone re-do the screws.

Could be the holes for the stands are a bit off in the wooden back of the Diva, wouldn't take more than a couple of mm's.

[Graz]

When the Apogee classic panels are new they are installed with considerable lateral tension from top to bottom of the panel. The material is reasonably strong, but cycling of humidity/dry plus the tension can pull at the frame. The FR and some Scintilla's got around this by bracing the back across with steel plates - effective for strengthening the frame laterally. Such plates can be aesthetically pleasant if done right, and can be fitted with GREAT care without harming a bass, though the procedure can be a little tense:)

I will consider a retrofit for this as a package over the next few weeks.


The later Synergy had deep lateral bracing to prevent frame movement, as do the all new Duettas (soon out).


Take care - Graz

[Zardoz]

Thanks for the input Jon and Graz. Jon, the alignment of the stands seems to be fine, but that is something I will look into. And Graz I think you have hit it on the head. Let me know if you do come up with something, although my fix seems to be working at least for now.

Best,
Z