LTSpice - chime's ding simulation

[atferrari]

I intend to replicate the sound of a simple clock's chime. So far, using LTSpice, I managed to control attack and decay times.

Please check the sound in the attached .wav file. I understand that kind of a thump is perceived at the start, which I find annoying and far fom nice.

The signal, taken at the output after several DC blocking caps looks as shown. Really.

My questions:

1) Do you agree on the initial anomaly? My hearing is definitely bad so I do not trust much on what I perceive.

2) If so, is it an artifact created by LTSpice when sampling the signal and passed into the .wav file?

3) Or is it that initial jump of around 300 mV pk-pk, the reason of it?

4) Or just my sound card?

Comments appreciated.

Sorry. Had to add .txt to upload the .wav file.

 

[ericgibbs]

hola at,
Any chance you could post your LTS asc file.?

E

 

[atferrari]

Here we go, Eric.

EDIT to add:

Honestly, Eric, I intended to discuss this in abstract irrespective of the circuit itself but maybe it is good to look at the circuit.

Just in case, please note that I needed to give some delay to trigger the attack and decay generators or otherwise they would not be properly "launched", well they would not start at all..

Not sure waht would be of all this in real HW.

Thanks for spending your time in this.

/EDIT

 

[ericgibbs]

hi,
The problem is due to the Attack, it Starts at 0V,[ which is full volume] then jumps to +V [ which is minimum volume] then decays towards zero to increase the Volume.

E

 

[audioguru]

I have never heard a chime with a frequency as high as your whistle. A chime should be a few hundred Hz to produce a Ding or a Dong.

 

[atferrari]

I have never heard a chime with a frequency as high as your whistle. A chime should be a few hundred Hz to produce a Ding or a Dong.

Me either, AG. Not the reason of my problem, if problem at all...

 

[audioguru]

Radio Shack had a wireless chime used as a motion detector. Its ding-dong was irritating squarewaves that I filtered into a mellow sinewaves then it sounded good. But it also produced a very loud THUMP like yours at its beginning.

 

[alec_t]

Hi Agustin. Try this :-

 

[atferrari]

Hola Alec,

Thanks for the circuit. Not intuitive, at least for me but certainly simple.

In my circuit, by adjusting the attack time the thump is gone. That part seems critical and I would like to see how easy it is in real HW.

Next is to adjust the frequency, maybe add one harmonic or two and simplify the resulting mess. Too many timings to care of, I guess.

 

[audioguru]

Your "chime" still has such a high frequency that it sounds like a whistle.

 

[atferrari]

Yes AG. I will take care of it later because I need to implement a filter for lower frequencies.

 

[alec_t]

To simulate a bell realistically, in addition to the attack and decay envelope I think you will also need to add amplitude modulation having a frequency of a few Hz.

 

[audioguru]

My home was built with an American (Edwards?) ding-dong doorbell that had two different sized metal bars hit one after the other by a solenoid. It was not loud enough to be heard everywhere in the house. I replaced it with a cheap Chinese one that had plastic resonant chambers over each metal bar and it is MUCH louder.

I searched Google for my doorbell sound but most of them went clank-clank instead of ding-dong and some were out-of-tune.