Tweaking the Sonus Faber Grand Piano

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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.

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I wouldn't attempt anything much further without looking at the crossover and understanding what it is about 6" bass that is tonally problematic.

Simplistic filters don't work very well with 6" bass. Troels Gravesen has strong views on the right way to do this:
18W-8434G00

Those old SEAS 19mm ferrofluid tweeters are kinda flimsy. I have one sitting around retired. It has a Monitor Audio stamp on it, but I doubt it's anything other than bog standard. I see the impedance goes high at high frequency in the original SF model, so your attenuator might help for the smooth sound with a lot of amps.

Putting the crossover in sand sounds like an idea, but where does the heat now go? I don't mind hard soldering basses, but tweeters are fragile, and good clips and crimps seem to work well enough.
 
The results one might get from modifications in general may or may
not be real. Placebo is a known phenomenon. Let me clear some of these.

Firstly, by default the tweeter is already sealed and therefore protected
from the waves that travel in a box. Why seal it any further?

Secondly, have a look at the traced impedance plot and its Fs peak
well damped with ferrofluid and the FR plot that includes
a raw driver response and a filtered one ( 4R7, 6u8, 0,22mH, 5u6).
A series resistor followed by a 3rd order electrical imaginary filter.

The OP said:" 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."

How could the Fs of the tweeter be audible if we know that it does nothing
audible to the sound?

If we look at the review, there seems to be going on something odd that
qualifies for an upgrade, but that would mean to heavily modify the whole
mid to tweeter range, not some meaningless aesthetic changes.

http://www.stereophile.com/content/...-loudspeaker-measurements#cBXWdfgusbULXZZi.97
 

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This is what drives newbies to DIY Audio crazy.....can't even get simple agreement on the facts....as Lozjek says the tweeter is already sealed...what in G-ds name are you on about System7 that you can't even acknowledge the simple facts......next thing you know we'll have some well meaning but naive newbies running around re-posting that this tweeter is an example of an unsealed tweeter.
 
Hi Henni,

I'm always curious to see what improvements can be made to existing designs.

Easy mod and reversible,

DIFFRACTIONBEGONE REVIEW

A less reversible mod would be bracing.

If you do start to notice changes in bass from loss of internal volume you could try some port stuffing too, maybe with drinking straws.

Look forward to seeing some positive contributions and pics!

Oh and of course there's always the option of making them active :D
 
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It's funny how people with nicks
such Devil in details and Lojzek ( logic ?! )get lost in such discussions.
:rolleyes:


Let's examine our dilemma right at the origin. As an example of how a
manufacturer treats an open tweeter, I have chosen the Eton ER4 and
the measurements that are made with and without the back side damped.
You can see the holes in the response when untreated.
The Seas doesn't mention anything about their tweeter being open or in a
need to be additionally sealed in a cabinet. They have managed to produce
a front side of a tweeter without the need to use extra screws, only those
that go in the cabinet baffle. That was their angle in reducing costs. The
performance measured is typical for a solid quality piece of technology.
 

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If members are still posting and commenting it is still new!!! Love watching people "fight" over nothing. BTW, Lojzek, some humility is nice, you sound like you know your stuff, but don't discard everything right from the start without any explanation. You explained in your second post, the first one just sounded conceited and "godly". Just my newbie opinion, carry on with the discussion.
 
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