Tweaking the Sonus Faber Grand Piano

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I didn't realise how old this thread was either! 2004!

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Obviously the most useful upgrade would be a better constructed tweeter.
H1280-06 22TFF

You'd need to attenuate that one by about 6dB at least. The woofer is "interesting". No dustcap, and a huge hole at 3kHz. Guess it shows that a dustcap acts as a midrange and "sings its own tunes" as somebody wisely remarked.

But without a schematic of the speaker, it's hard to suggest real improvements. But I certainly don't like the impedance, which doesn't look first order at all.

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Crossover

[QUOTEHi Hennie, I know this post is old, but can you explain how you got into the lower compartment, I thought about removing the side panels, but it's not easy, I can't get the little brass buttons off without damaging them, is this the only way in?

=Hennie;532044]I have bought good second hand items many times in the past and tweaked them for better performance. As far as speakers go, that included Sonus Faber. Perfectly good commercial designs have compromises inherent in the design to reduce manufacturing costs.

Here are some examples of the modifications I did to the original Sonus Faber Grand Piano to make it sound better. A lot these mods can be applied to other speakers too if you decide to buy second hand and tweak. Some of these mods can be made reversible.

I stabilized the clip-on interface of the Seas 19TFF1 tweeter with a few drops of epoxy glue. Cleaned up the treble somewhat. Only reversible if you buy new tweeters from the Sonus Faber agent. The standard 19TFF1 won't do, because the originals have SF's logo on the face plate.

I isolated the tweeter from the pressure of the mid-woofer, ensuring that it operates in its own sealed chamber. Fortunately this was easy to to, since the tweeter did not protrude behind the thick front baffle. This resulted in significantly improved treble response with less fatigue. A stethoscope test with the tweeter disconnected led me towards this mod. This mod can be made reversible.

I soldered the cables directly to the driver terminals, removing the push-on lugs. It is funny that they use expensive gold plated terminals on the outside of the speaker and dubious connectors on the inside. Sounded more fluid. Not really reversible, because the woofer terminals are gold plated.

This speaker has a dedicated crossover compartment. I filled that with clean sand, giving better stability. With most decent speakers a worthwhile improvement can be had by removing the crossover from the cabinet and putting it in a separate enclosure, maybe damping it. 100% reversible.

I tuned one side panel per speaker to a different frequency by attaching small lead weights. The idea is that the side panel resonances would be less noticable if they are not coincident. Used a stethoscope again. Can be done 90% reversible.

I changed the tweeter attenuation from a series resistor to an L-pad. I did this because I believe the fundamental resonance of the 19TFF1 was audible although cleverly voiced into the design. The L-pad design made this resonance almost inaudible. The speaker was also too bright. This was also rectified with the L-pad. 100% reversible.

These tweeter isolation and panel tuning mods decreased the internal volume somewhat, but the bass alignment did not change significantly.

I now want to experiment with the cabinet lining material, because I want to reduce the tweeter output a little more, but I need to reduce a slight lower mid coloration before I can do that. If guys reading this have any suggestions, please respond here.

Last step would probably be to replace the Seas tweeter with something like a Hiquphon. And test out better caps in the crossover. It uses standard Philips MKP.

.[/QUOTE]
 
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