Jump to content

Recommended Posts

Before I leave for vacation I want to post this outview here. Jeff gave me a nice idea how improve the Honk circuit. Since the oscillating relay that generates those glottal sound goes into a weird state of metastability and produces voice like patterns, that behavior could be improved by additionally modulating it with noise or mix it with other sounds. This is possible because in the metastable state the relay behaves more like a crazy going loudspeaker instead like a digital component that only knows the states ON and OFF.

New schematic for the Honk

Schematic - Honk.JPG

A modulation voltage is amplified by the transistor T1 that controls the current for the oscillating relay Rel-1. The generated sounds are transformed by the mechanical spring ME2, going through the screw ME4 that does the mechanical bias for relay circuit breaker and finally into the membrane in the resonator tube ME3. The whole arrangement consisting of the oscillating relay, the spring and the membrane with the tube is in fact a metastable system with fragile points of operation where different frequencies are generated that get bounced forth and back between the end points made up by the relay and the resonator tube and are susceptible to any changes.

Link to comment
Share on other sites

As per usual Andres, AMAZING. The actual construction of the unit is second to none. You really should try just a tiny bit of "echo to extend the voices a bit.

Did you just use what we in North America as "Saran Wrap" for the Membrane (modulated end of the tube) ?? 

Edited by CanadaKim
Link to comment
Share on other sites

14 hours ago, CanadaKim said:

As per usual Andres, AMAZING. The actual construction of the unit is second to none. You really should try just a tiny bit of "echo to extend the voices a bit.

Did you just use what we in North America as "Saran Wrap" for the Membrane (modulated end of the tube) ?? 

Echo or reverb is a very good idea Kim!  It could add up as an improvement to the oscillations in the spring.

Saran wrap I don't know. Need to google this.

Link to comment
Share on other sites

  • 2 weeks later...

After some discussions with Jeff I tried two improvements today.

  1. Changing the relay driver from voltage control to current control. I got better results with this technique with the coherer and wanted to see if it pays off with the Honk too.
  2. Modulating the relay with an audio signal, especially with the signal from a microphone in order to establish an acoustical feedback loop.

My first goal was easy to achieve and the results are very good.  While adjusting current and the spring tension the device is going through different modes. It seems to be favorable to adjust the spring in a way that there is no oscillation on a single tone or in other terms, the use as a horn has to be avoided. The voices are hiding in the areas where the systems is in a noise mode and provides a good modulation. Voices have a good pk modulation and a remarkable voice characteristic. I exported some samples. They are structured by first showing the raw signal and after 1s pause the same signal processed. Processing was done by applying 30dB noise reduction by using auto spectral substraction in WavePad and occasionally a 250 Hz high pass. In the following table I provide the decosing translated into english.

The second goal was interesting but gave no usable results in respect of ITC. In fact I got some nice feedback patterns that proved my theory, that the relay, in this mode, is more acting like a loudspeaker. Here are two sample exports, however as I said without voices.

Microphone Feedback.mp3

Microphone Feedback-2.mp3

What I want to try now is to use more low frequency signals that give more interruptions to the oscillating relay in order to form a better speech pattern (segmentation of words).

Also I decided to give the "Honk" another name and I came to the term "VISPRE", standing for "Vibrating Spring and Relay" that also shows a phonetic similarity with "Whisper" what I think is a cool relation.

 

Link to comment
Share on other sites

And here some results with my latest hack. I am exciting the osillating relay with pulses from a NE555 with adjustable duty cycle. The impulses are mixing with the inertia from the VISPRE givin a fairly good entropy. I would not say that the results are really better but there is headroom open in my eyes.

 

Link to comment
Share on other sites

These are great results Andres. I think the NE555 pulsing is the way to go in trying to stimulate more defined word structures, esp seeing you can alter mark and space timings. Would a shorter spring with less inertia be more effective with trying to obtain shorter responses? This is a very intriguing device. Id suggest trying scrambled speech audio into the microphone ?

Link to comment
Share on other sites

I worked like crazy to finish the first prototype of VISPRE unit 1.

PCIMG_2021-08-30_19-14-06.JPG

It shows endless modes depending on the adjustable spring tension and the driving current. An additional feature is a microphone that can pick up sounds (also VISPRE's own sound) and modulate the relay with it.

Basically the device has two main modes, the intermittent mode and the continuous mode. Here some examples with intermittent mode. Files with only one content are  NOT processed. Files with two contents separated by a pause are showing the raw signal at the start and the 30dB auto substraction denoised signal after the pause.

 

Da braucht man garnichts zu machen.mp3

Da wird dein Test noch nachwirken.mp3 Das müsste jetzt zumindest ausreichen.mp3 Das werdet ihr bald im Projekt darstellen.mp3 Das wird euch der Bergmann selbst noch zeigen.mp3 Euch wird ja bald der Parkplatz bestellt werden.mp3 Fragen.mp3 Sind bereit.mp3

The 2nd mode is characterized by a steady noisy signal. Here some examples.

Sind Reisen.mp3
Wir sehen Probleme.mp3 Wird besser.mp3

At the end of the session I got one last message. A spirit said "Wahnsinn" -> "This is crazy"

Wahnsinn.mp3

 

Link to comment
Share on other sites

I really like this method of yours Andres, and I deeply admire the construction and ingenuity of the design. It is definitely moving forward. The sound generated has a strong glottal base frequency, and does transform quite well. I wonder if it would be possible to add some form of random pitch inflections to give a closer resemblance to human speech? Also maybe two different springs in series or parallel would add more complexity to the voicing?

Link to comment
Share on other sites

7 hours ago, Dr Jeffers said:

I really like this method of yours Andres, and I deeply admire the construction and ingenuity of the design. It is definitely moving forward. The sound generated has a strong glottal base frequency, and does transform quite well. I wonder if it would be possible to add some form of random pitch inflections to give a closer resemblance to human speech? Also maybe two different springs in series or parallel would add more complexity to the voicing?

You are certainly right, Jeff. I purchased a set of different springs to try them out and I am making up my mind about a random pulsing of the rely. The intermittent mode turns out to be favorable if the relay can be excited by random pulses mimicking speech patterns. I need to make another test setup for this development path, something where I can easily change and adjust the spring and feed into the relay whatever I want. Something like  a test bench.

The prototype I made is just for "freezing" the current design and to have something to work with and it will serve me as a reference design for the next development steps.

Keith was the one who occasionally came up with the idea of an artificial larynx and pharynx to give the spirits something as close to the human "speech apparatus" as possible. I think he now is more looking for a software solution but it turns out that his idea was right. I'm confident that in the future we will realize a continuous talking apparatus the spirits can use.

Link to comment
Share on other sites

21 hours ago, CanadaKim said:

How do you keep the spring from tearing through the Diaphragm material ?, and what id the material used for the Diaphragm?

I used a small sheet of metal behind the diaphragm with two tiny holes in it. The end of the spring is shaped like a hook. The pin of the hook is piercing the diaphragm and metal sheet and goes around it. Thus the metal sheet is pressed against the diaphragm and not the spring itself. The diaphragm is mylar from a zip bag.

Link to comment
Share on other sites

More experiments today. I could achieve the reception of some snarling voices. I used the neon bulb receiver to generate nice random speech patterns. A bit of electronic is shaping impulses for the relay from them.

Hear the audio clips.

Link to comment
Share on other sites

Some more improvements. I guess now it's time for an updated schematic.

Here is the new schematic. It will be the base of my new prototype. I will need a bigger box to put this all in since it now includes also the neon bulb with its electronic components.

662094539_VISPRE-Unit1.thumb.JPG.62f0d2ba365750c0aef859100460c6a8.JPG

 

Link to comment
Share on other sites

  • 2 weeks later...

Basically the device is finished but I am still doing optimizations. Today I recorded a longer sequence to become more familiar with the sound and evaluate the capabiity for generating continous speech. Basically the speech is still too fast and sounds like coming from a tin can but I never made a device before that could generate a continous stream of voices with almost no noise.

The following sequence was slowed down by 20%, 250-Hz high pass filtered and 20% denoised. Moreover I inserted 100ms silence gaps between the coherent statements. You will not comprehend anything by hearing the clip in one piece but certainly if you select shorter sequences and play them back in a loop.

Recording 2021-09-20 Processed.mp3

Then I got the idea to route the signal picked up from the internal microphone in the VISPRE through the linguaphone speech filter. The result is very weird.

Lingue 2021-09-20.mp3

Link to comment
Share on other sites

New schematic. I am making small improvements every day.

VISPRE electronic schematic

206587958_VISPRE-Unit1-electronicschematic.thumb.JPG.d301a6b26f6bd5d78df0d41fa9a1dd05.JPG

It turned out to be useful to make the amplification of the impulses adjustable. As a result I don't need thee adjustable threshold for the impulse shaping anymore and the relay driver is now a darlington transistor.

 

Link to comment
Share on other sites

Some more refinements today with amazing results. I checked the voice generation with maximum spring elongation of 15mm. In this extreme setting the relay oscillations are shortly before tapering of. This configuration gave very good results too. Another improvement is to not use the external microphone to face the tube outlet directly. Instead it is favorable to place VISPRE and microphone both facing a wall where the sound waves of the VISPRE are reflected from before entering the microphone.

The following audio clips are all in german but I hope you get the quality level and the excellent SNR.

First I started the recording with the activated Lingua in order to adjust recording levels. After switching it on I got the message "Du machst das Filter" -> "You're using the filter now": Du machst das Filter.mp3

I think I can state that these are the best spirit messages I ever yould get on a regular base.

Link to comment
Share on other sites

  • 2 weeks later...

I stole myself some time today because the work with the light bridge is proceeding very well and thus I realized an idea for improvements with the VISPRE.

IMG_20211009_135452.thumb.jpg.efee3880c4642ee25823c53e5b7827fa.jpg

I wanted to replace the oscillating relay with a loudspeaker. The sound of the relay is very rich but also a bit dull since it was not designed to create sound.

IMG_20211009_135518.thumb.jpg.ed6cc7d273929fd61a47a1cf9c568db7.jpg

So I employed a loudspeaker with a piece of perfboard to connect the spring. First impression was that the sound had more granularity but was lacking speech. Then I considered that the relay was self oscillating and the loudspeaker not. Thus it emitted more or less only the envelope of speech.

IMG_20211009_135538.thumb.jpg.bcabd9f5310aea1a91d2761f4bc7641b.jpg

So I made a little oscillation circuit with an NE555 that generates a square wave signal that can be tuned between 150Hz and 400Hz. The neon lamp impulses are switching the NE555 just on and off. The results are much better now. Here the only english sample I got.

We've been all built with the stars:

We have been all built with the stars.mp3

The fidelity is not bad and the cool thing is that I can tune the pitch electronically now by adjusting a potentiometer on the NE555 circuit. In the current VISPRE the distance between relay and diaphragm must be properly adjusted to pick the right pitch. For the new design I won't need the mechanical screw arrangement anymore and the loudspeaker can be placed fixed.

While granularity is improved the sound is very "thin" now. However I already have ideas for an alternative oscillation circuit. I guess the next version of the VISPRE will be easier in mechanics and better in performance

I use the current VISPRE just for testing and will reestablish the previous state after my tests are completed. The new design will give birth to a new prototype.

 

 

 

 

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

 Share

×
×
  • Create New...

Important Information

We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue.