The Modified Filter

The filter was reworked due to the addidion of the The Ceramic Accuton upper bass Head
After a while one comes at a point where one want to tune the speaker.

I wanted to upgrade the already very good M-Cap from
Mundorf with there even better M-Cap Supreme.

 

Here you can see the 4 parallel Mundorf 22 uF M-Cap Supreme. 
You can compare the size of the 6 dB/Oct filter  with the size of a normal 12 cm CD.
In front you see the equivalent (3x33uF) Mundorf M-Cap's

you can notice that an extra C was needed (mounted on top of the 4 big 22 uF's)

Here you can observe the floating inner cabinet.
The filter is in its own a separated airtight cabinet, mounted on a separate board which is, once more, decoupled from the cabinet.
This all should give perfect conditions for the filter.
The filter is free air wired. The inner cabling is QED silver anniversary.

When I added the Accuton ceramic head I completely rework the MSW filter
The filter is an electricaly 12dB/oct in stead of 6 dB
As the moderarte MSW boxed impedance rise (from 8 Ohm to 17.5 Ohm at 92 Hz)
the impedance correction components where left out
The filter was optimised with SoundEasy
The capacity is lowered to aprrox. 31.5 uF. Its composed of a recycled 22uF and 5.6uF mCap Supreme
and a new 2.7uF mCap Supreme and 1 uF mCap SupremeSilver Gold Oil capacitor (the one on top).
The coil is also from Mundorf, its a M-cfc12-12 MCoil Foil coil 1.2mH AWG12
The Big coil is also a Mundorf MCoil Foil coil (M-cfc10-39) 3.9mH AWG10
paralleled with a 12 Ohm MResist SUPREME Resistors from Mundorf
The heavy coils are mounted on a piece of Noene to destroy enventual vibrations.

This is the frequence response and distortion of the Accuton and Manger (without the active woofers).
It is measured in the room (at around 50cm on axis of the MSW)

Here is the compete optimized filter diagram created in SoundEasy.
The 1.05 Ohm R17 (3x || 3.9Ohm || 6.8 Ohm MResist SUPREME Resistors)
together with R11 0.32 Ohm from the 2.7 mH MCoil Foil coils)
forms a divider with R13 to match the sensitivity of the Accuton driver
to the MSW sensitivity.
I modifide the driver names as D0 D1 etc to clarify
Also the R13 can be changed. It are in reality 4 x 33 Ohm in parralel
But I added a toggle switch to 3 of them to allows the end value to vary between
33 Ohm, 16.5 Ohm, 11 Ohm or 8.25 Ohm. Each step gives a 1 dB change
My current preference is the 11 Ohm setting.

 

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