Bob Brines said:
Thanks Bog,
i double te top ..
i just made the drawings used 7/8 " (22 mm) MDF
Instead of using a pvc tube i am using wooden rings
to eleminate vabrations of a tube..
Must i do something about the vibrations from the frame of Fostex
i read other users of fullrange speakers did it to?
Greetings Weidok
Hee Leeuwarden welcome.. worldwide...
weidok said:
I've not used a driver yet that doesn't benefit from some judicial use of DuctSeal (the Phy-HP being the only driver i've touched that didn't actually have anywhere to put it). I won't install a stamped frame driver without some duct-seal treatment.
Morse probably had some interesting comments about the series of small tweaks he did to his.
dave
Hi Dave!
Funny you should mention the rope caulk tweak now - I just applied it to my first "post workshop move" speakers a couple of days back. As expected, it cleaned up the midrange nicely, as well as removing a bit of an 'edge' to the upper midrange (gotta be a basket resonance at work there).
The "felt on the back of the magnet" tweak had a more subtle, but still useful impact, so it's a 'must do' on any speaker with a ferrite magnet IMHO. I've run out of felt padding momentarily though, so the "felt on the insides of the basket legs" tweak will wait until next week.
Interestingly, one thing happened in this project that proved a complete surprise (though it shouldn't have): the improvised mounting for the binding posts proved a wholly inadequate solution (all I had handy at the time of construction was some perfboard and soft PVC type plastic to place as a gasket). Replacing those with proper 1/4" thick plywood mounts that I affixed with polyurethane glue yielded a substantial improvement in bass potential from these tiny little 5.6L RS40-1197 BR/folded TL hybrids. Midrange clarity also apparently suffered from the resonances that these improvised mounts introduced, since there was an increase in image depth accompanying this change. I'd expected a small improvement in performance, but the results of this experience make me wonder about the potentially deleterious effect of the "weak wall" that many cheap mounting cups for speaker connectors constitute. On "no holds barred" projects, I shall continue my practice of using binding posts with long enough shafts to be used without any mounting plate assembly at all - just a hole for each post through the cabinet.
One last thought in the "cheap but critical tweaks" department is that on office speakers some thought must be given to the acoustic properties of the desk or table they're to be sat upon. The RS40-1197's have enough bass now that they can really make the top of that desk resonate (unpleasantly) and muddy up the sound. This has (mostly) been cured by using 3/4" thick rubber feet (3 per cab) on the bottoms of the speakers to act as a decoupler.
Hope I didn't put anyone to sleep!
Oh well, time to get back to grading papers....
All the best,
Morse
Funny you should mention the rope caulk tweak now - I just applied it to my first "post workshop move" speakers a couple of days back. As expected, it cleaned up the midrange nicely, as well as removing a bit of an 'edge' to the upper midrange (gotta be a basket resonance at work there).
The "felt on the back of the magnet" tweak had a more subtle, but still useful impact, so it's a 'must do' on any speaker with a ferrite magnet IMHO. I've run out of felt padding momentarily though, so the "felt on the insides of the basket legs" tweak will wait until next week.
Interestingly, one thing happened in this project that proved a complete surprise (though it shouldn't have): the improvised mounting for the binding posts proved a wholly inadequate solution (all I had handy at the time of construction was some perfboard and soft PVC type plastic to place as a gasket). Replacing those with proper 1/4" thick plywood mounts that I affixed with polyurethane glue yielded a substantial improvement in bass potential from these tiny little 5.6L RS40-1197 BR/folded TL hybrids. Midrange clarity also apparently suffered from the resonances that these improvised mounts introduced, since there was an increase in image depth accompanying this change. I'd expected a small improvement in performance, but the results of this experience make me wonder about the potentially deleterious effect of the "weak wall" that many cheap mounting cups for speaker connectors constitute. On "no holds barred" projects, I shall continue my practice of using binding posts with long enough shafts to be used without any mounting plate assembly at all - just a hole for each post through the cabinet.
One last thought in the "cheap but critical tweaks" department is that on office speakers some thought must be given to the acoustic properties of the desk or table they're to be sat upon. The RS40-1197's have enough bass now that they can really make the top of that desk resonate (unpleasantly) and muddy up the sound. This has (mostly) been cured by using 3/4" thick rubber feet (3 per cab) on the bottoms of the speakers to act as a decoupler.
Hope I didn't put anyone to sleep!
Oh well, time to get back to grading papers....All the best,
Morse
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