General instruction in the use of FA251/-501
Copyright 2021 © Troels Gravesen


The instruction here is meant for the FUSION-BAD, ScanSpeak 10/12" subwoofer, SBA-741 bass module, Ellipticor-A50-II, ScanSpeak MUN-17, The Loudspeaker-1, The Loudspeaker-2, The Loudspeaker-III and for the use of the modules for bi-amping.

As the FA251 and FA501 takes the signal from speaker binding posts, this is an easier way of implementing the Hypex/DSP plate-amp.
For The Loudspeaker-1-2 , MUN-17 and 12" ScanSpeak subwoofer I recommend the FA501 delivering 500 watts. For all others the FA251 is more than enough. I know people don't believe this, but it's your choice.

Hypex FUSION FA251 and FA501 module


Download HYPEX FUSION manual here.

Download Hypex Filter Design manual here.

Download the latest Hypex Filter Design version 4.981 here.
You need a PC to install the software.

Download actual speaker software HERE

Download software for SEAS CNO-4 HERE.
The CNO-4 zip file contains 2 files:

The CNO-4_FA501_4-6-8dB is the file you should use in case you do not add a high-pass filter before your power amplifier.
The CNO-4_FA501_6dB_HPfilter-PA is the file you should use if you add a high-pass filter before your power amplifier.

Un-pack zip file and place the folder (not the Config.xml file) in your "FilterData" folder in "My Documents".
(The actual file is the Config.xml file, but in the HFD software you open the folder and don't see the Config.xml file as such)


Click image to go to Hypex website. Now version 4.981

Installing software

Connect the FA251 to your PC via the USB cable.


Double click the HFD icon and open the program.


You have this and need some settings here.

Set Volume to 0 dB.

All presets must have Analogue SUB setting when taking the signal from the speaker cables.


Next click Device settings:

- and you have this:

It should look like this and there are options here for your personal preferences, like Wake on line, etc.
Above my preferred settings.

Close the window and click Filter design:

- and you have this:

Click new FA251:

FA251 will come up in the menu when connected and active.

- and you have this:

Open -

- and you have this:

When installing your HFD software you'll have a folder in My Documents named Filter Data:

Choose FUSION_FA251 and click OK, and you have this:

The FUSION BAD has an LR2 low-pass filter at 150 Hz, a 4dB boost at 30 Hz and an LR2 high-pass filter at 20 Hz to please vinyl lovers from having sub-sonic trouble.

The current FA251 program for the FUSION-BAD  speaker has the same gain for all three presets. You can adjust gain level for the three settings rather than adjusting level on the volume knob on the Hypex panel.


Upload all presets.

So far the programming. Disconnect the Hypex module from your computer.


Connect speaker cables to "high level input" at + R -. Plug follows the Hypex kit.

Like this:


Set gain in the middle (small click stop) and adjust to preferred level.


Connect your speaker driver

Turn to page 14 in the manual and you'll find the following information:

The bass driver must be connected to red and black wires. Red = plus and black = minus.

Mostly I connect 1 and 3, grey and black, for MINUS - and 2 and 4, blue and red, for PLUS.
I have a pair of FA501 for test purposes built like this:

Had some oak leftovers and made a pair of boxes for FA501 and added speaker terminals for the sake of ease.

The FA251/501 gain structure

When all gain settings are set to 0 dB, we have some 19 dB gain from the Hypex modules. When using the High Level Input option (signal from the speaker cables) we have to know the gain setting of the program uploaded to the Hypex module and the setting of the potentiometer knob to get the same gain from the Hypex module as from our main amplifier driving the midrange and tweeter.
Using the FA251 and FA501 we don't have to know the actual gain of our main amplifier as the Hypex takes the signal from the speaker cables and if we use our Hypex as a straight power amplifier (no filters, etc.) we have to set our programs to ~+6 dB to get the same level output from our bass driver as from our midrange driver. So done in my program for FA251 and FA501 modules.
Download here:

Download program for FUSION-BAD HERE.

The program goes for both FA251 and FA501. There are two programs in the zip file, one standard with bass boost and one without. Un-pack the files to your "FilterData" folder in My Documents.


Options for adjusting to room conditions are limitless.