Acoustic Modelling 6.....
 Fig 6

Why stop at a two delay gong? What about a three delay array?
I thought that maybe if the plate was wrapped round into a cylinder, that might produce more of a  bell sound. If you do this there are are extra dimensions created in space; that caused by the springiness of the wall of the cylinder material, which is deformed slightly when the clapper hits it, but springs back in oscillation. I thought the frequency of this extra vibration mode would be fairly low (long delay). Then maybe the length of the tube that’s formed might add further resonance to the sound too.

In the next patch diagram below I experimented with adding just one extra long delay in series to the simple plate model plus and extra mixer to hold it all together. This I hoped might at least give the sound more depth.  In this 3-delay array, delays 1 and 2 form the time delay system over the surface of the bell, and delay 3 is the deformation series at a much lower frequency.
This view may be wide of the mark, but the model does produce an extra depth to the sound, a more complex and rich sounding decay. With controls for 3 delays, which could have an inverted output or not, 7 feedback balance points, plus a large number of different ‘strikes’ to play with, a large variety of gong and bell type instruments have been constructed with this patch. It’s getting pretty complex though and getting the right settings to produce the sound you might be after requires much patience! The technology of real live bells is pretty complex to get them to sound the way they do so you have this hard work to do too, assuming the model can hack it in the first place.

If that wasn’t enough, there was also something I hadn’t thought about. The effect of listening to a tiny point of monophonic sound somewhere between two loudspeakers is not really convincing for a big instrument. It somehow needs physical size. The addition of reverb can sometimes help, but often is not enough. So I thought well.., a big church bell is physically wide and swings to activate the clapper. This distorts the shape a bit altering the pitch and the sound as it swings. Adding a little help from stereo multi-path chorus type of effect, I thought, might just help both size and movement.  One with perhaps 6 delay paths (3 per side), slowly moving in time, (which is just like the one I happened to have made some years ago!) might help. Stereo width was improved by this and the added movement improved greatly the quality of the different bell sounds.

Another way of improving width for the plate and bell models, is to take left and right output channels from different points in the patch; d1 and d2 are good starting points for this. Of course you could take the ‘striker’ point out as well and stick it anywhere in the stereo field or mix in other things too with the striker sound. Listen to the sound example below the following patch diagram for the results of my best big bell.
3 Delay gong patch.
This is quite complicated so I’ve highlighted the original two delay gong section in a deeper blue. Added to this in the bottom right corner is a second audio mixer which adds the first two delay outputs d1 and d2 and feeds the sum to the third delay bottom centre. It’s output is fed back to the first audio mixer to create the 3 delay resonant loop array. It is also fed back to the second mixer so that enhanced third delay resonance is possible, if needed. The first mixer now has grown to 5 inputs to enable audio to be fed into the patch (sound clip below).  The pitch control is in a salmon colour. Of course following this general logic could lead to arrays of more delay elements. I only had 4 at the time. The track called “The Tank” from my “Void” album is an example of using bigger arrays.
[SOUND EXAMPLE 6: Human bell...  MP3  (128kbit/sec)].

 In this sound example I’ve used all of the above techniques to create a big bell. Making use of the extra audio input,  the bell is excited  by not only the striker but the voice of a well-known UK TV astronomy presenter too played back from a tape recorder. The patch starts with the strike of a fairly  large bell, then the voice is added to the patch with controls set to make the voice sound in the bell. The controls are then adjusted so the voice gradually grows closer from within the bell, which changes pitch when the bell is struck by the press of a keyboard note. Finally the voice retreats back into the bell sound. Getting the settings right to produce this took a very long time!
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Using a modular analogue synthesiser