Amplitude Modulation in MSoundFactory?

[Held]

What's the best way to do Amplitude Modulation (AM) between two oscillators in MsoundFactory?

The best way I came up with is to generate a custom modulation source with one oscillator and modulating the volume of the other oscillator. That sounds pretty good with oversampling, but I'm hoping there's an easier way to do this.

The Merger module seems like an obvious candidate, but I don't see AM as an option there.

[vanerio]

What's the best way to do Amplitude Modulation (AM) between two oscillators in MsoundFactory?

The best way I came up with is to generate a custom modulation source with one oscillator and modulating the volume of the other oscillator. That sounds pretty good with oversampling, but I'm hoping there's an easier way to do this.

The Merger module seems like an obvious candidate, but I don't see AM as an option there.

What about just 1 oscillator modulated by a LFO with 'Follow note frequency' enabled?

[Held]

What about just 1 oscillator modulated by a LFO with 'Follow note frequency' enabled?

That's a good suggestion. I tend to forget that the LFOs are fully fledged oscillators as well. They don't have an option for anti-aliasing, though, so that might be an issue. But I haven't done enough tests to tell for certain.

If I understand Wikipedia correctly, the main difference between ring modulation and amplitude modulation is that amplitude modulation maintains the frequency of the carrier while ring modulation removes it.

Following that logic, using ring modulation and setting the dry/wet control to 50% should create the same result as amplitude modulation.

Maybe Vojtech can let us know if that's correct.

[vanerio]

RM and AM are similar, but AM modulator signal has been converted to positive values only (I am not an expert though). So to do that ,you can do several things:

Seting an Oscillator as modulator: In this MSF preset you have a multiparameter to compare methods to do the exact same thing, from math operations only, to mix RM and math operations, or to directly offset & scale modulator osc.

Or you can use an unipolar LFO, what I think is the easy way, but as Osc´s Volume knob is not linear, it will produce a stronger effect! Have that in mind.

Code: Select all

$eNrdWU2MI0cVLk8CinKBA+IAEmppQhTIDu32eHbngrw1Y3uwmF477pnZzrHc-cZuTbnKqqqejPewiAMi4pQrHODAKZcVHJAAhR8hbpFyiIQiDpE2QjkhoUUcEBIS6PWPp+2xd23vJIvog9tV9b2qV19VvXrvNXH3fN-1ZCzCJguMVGMNxkSirwndJE6Jbh5w2WNcH7FeUqT1OozMgIQkeR7WEBGF0AHVDgw7B+IQegJKR1KQKnnh84R+67XjkWbDEY9EH1sbYWSk8qJ70GB6TLSzXd6+sevsFluIdqo7Ozd2d6qE7sdKgTAdBRpMq050nZ1H4f3GBfYJ+j51LVfGnJlIitDKqgl1Y26iDlNsCAaU3pecs5GGEFVw2cVhs73HZXCWjOZYFJGcA4-uJR3hZA+73ohHxkCikpPN+c23bs+0VHI2HtVoh8f9SBA9xSnxvbiXtkxq0qI3YdsDDoGBMO+gfKOcLcFVZTNhnfdCqI+zeh1-7rAhEN3WQcQ5M1IR2ow5n9Rayez1WUsguAuCDZGSkr-HxFmZ2Ff0SnfBieTxEArz3DwWkZaiIViPQ4HbEt3s3HVdGQLR9Uhja0iSulyYzKPfd9v1fBA6tcMe1ei+jIUhzobfLZO8UKJaBWWiD5ttnNJFmYQPHuzvfPX1D35n+13ncbhcDdv2vQEbAaHeUaPT6Ta8xhFxiG3bRVpLy9FaITTlIttfOcP4rx2j9p8M2emh08R5finiW-VWR8m+YsP9ARN9SLtERaeq95mBvlTRPVDzj8tc5vz2CFRyejShHalN3nspKXkB41Ckfw7RpYxol5lBkeKvl7+xM5fhjSLD7diMYtMSIVyUsa9C2SHOf5ZfgZTGxIKM+Njqja1ACm2YMEhp0fgdRsPI5BUv3b4+hueQs7GAnFefBTk0DJ81KYnFe24BKbh4c0l5LvvnGWAciy0xik1SSnhJijktpUKrc41biny6JD2fkwSqD1O2q+uuQFK+ecinylk3En1rKMPsiid0s67Gd2HCHblW7tAqXd7W-jVd1NgrNYYFZw6hhyD6ZoAXWkOcA5doSKnWUX+idOPOSW5VNyaSlbUlt9eWrK4tubO25M21JW+tLbm7hmRDnDvEP1IwlFzO9yQQU1kCs70EproEZmcJzM0lMLeWwOw+CZNGDg1xTmhKcsER6QIHpoGE-3777++7vU6N1iFg4wLCi7Vhkbj0gp4w2mGzjQ4tM0DCf-36Oz8Pmp+7PbN+UyKXO4U2JefyjTvSJK5KwaOacp6ueDdT-szDWlJHw5CE33-nB87x8Z9qqVYVspwaCXh7FXB1FfDOKuCbq4BvrQLeXRrcZSKUw+SEMaFPpRpm5n-hoXzBzqUqa0ltryVVXVHq2zDWuHOcNeVWndsJcBlEZr1Bp4TXHXmm4bITDOl1rGAxIDLBYA9E6C+EuDK8OwDgCwFH0bCn4FZ1IWBPATODcmUhoHExQkUjKRxnISi3V4va0by0T09n25PkSWbSpltm8hdkpqJMJj6dGciQ0NRZQodKE3rCeAxZzdjqMXFmoc9FqGdglIXGn6HeCCAs2NxEqhB3Hhy30pQM9lQh+g4uPCdY77EhdOUbuOoHx619yaUiulq-1ayWm01CUY3JMFhAXcvoblquDKPTCIPTvN4hmroYZKU+fF5dSeC9sdU+PdVgXk7sbWi1dVC5BG1PZGNurJcfi63m2MNmm9AJk130DPWlE+xPWgqglOsDEHgHSGVtWV3X2rJyqWnqSOphJx3jPdK4MF28UUonvVdyBHlUI1PPbJmgW7yUJhgcX48uV3VYVZdX-4d0SbbEU+ny5LVaVpckR2RtWclRn7xHUputkZIBmhfRR1yyf5PQJFP3vXff+dlb1Y9rNFU13LX-8Ye99-9YW0L9h7X8fXSMz8e1v73oJe+8-rrVT32inOnff+V7f33tlz+uFWbz7vlvf-Il+zeT2XzZ-vClz373F4+fzY9+iM+vatPvtyfvdRfjGnfp1V27ijKOtWWlWT8MdC1ry0pzoLlizY-ufeHBwUcT1sw3X-zgp6MPV9sD89+P0E2dvlom6c4ksx5ar6BdtobJPaO-lt80+WVQuGo6oAIQBoPkT+xmeVqzna99nmx+3NJfYaYyy0zX-X-hJbnO6mpsY2ZlNVa2Z1k5bLafio43v-jn9-7p-eVZb5Orp5I6Rct8Gc2mp3I871Ri5mdfCqMk5+jGUS8SfQ6YjxLAMXb1aWCic0i-b6UfwTAOrcN5FIA7+-GqRPPCkQL0uv0sqTVuGRi2xKkk9qTKMxgP+wcgFBDbT11hHFGZKMjzabZPOSbFzGBIbL8JzMQKMGXlZ1-e8uXFjyrzh36acZIJZ98JkjRZJ2MC-6tRFtM7G77LjIouLhtTairEvxuFZuAS35OxCgBTfnAacQMq-eBo2-b9-wJriqzO

[Held]

Thank you so much for showing me all those options to do AM in MSF. It was a lot of fun to play around with your preset.

I think I like the option with the math modules and the RM module the best, since the merge module comes with the convenient dry/wet and oversampling controls. The resulting spectrum looks like proper AM.

msf_am_math.png

The volume modulation with an LFO introduces additional harmonics due to the non-linearity of the volume control as you mentioned

msf_am_volume.png

While playing around with the math module, I remembered that you can also use the abs function to make a signal positive. Using this creates a bunch of harmonics and sounds pretty cool as well. But this also introduces a lot of aliasing without oversampling.

msf_am_abs.png

(I changed the modulator to be only 2 octaves above the carrier in all the screenshots.)

I really appreciate that you took the time to set up such a nice playground to explore different AM options. I learned a lot.

[vanerio]

Thank you so much for showing me all those options to do AM in MSF. It was a lot of fun to play around with your preset.

I think I like the option with the math modules and the RM module the best, since the merge module comes with the convenient dry/wet and oversampling controls. The resulting spectrum looks like proper AM.
msf_am_math.png

The volume modulation with an LFO introduces additional harmonics due to the non-linearity of the volume control as you mentioned
msf_am_volume.png

While playing around with the math module, I remembered that you can also use the abs function to make a signal positive. Using this creates a bunch of harmonics and sounds pretty cool as well. But this also introduces a lot of aliasing without oversampling.
msf_am_abs.png
(I changed the modulator to be only 2 octaves above the carrier in all the screenshots.)

I really appreciate that you took the time to set up such a nice playground to explore different AM options. I learned a lot.

Using the ABS function will not recreate standard AM, as AM is offsetting the entire wave, not just the negative part, but it will create of course a valid and funny alternative.
I am glad it helped you!

Edit: I just want to add, Vojtech, never stop being that crazy...the capabilities of your software are amazing

[Held]

I also tried using RM with 50% dry/wet and it looks pretty much identical to doing AM with the math modules. So this seems to be the easiest option after all.

msf_am_rm.png

[vanerio]

I also tried using RM with 50% dry/wet and it looks pretty much identical to doing AM with the math modules. So this seems to be the easiest option after all.

msf_am_rm.png

Mmm you are right!!
If we solve the next equation for a:

Code: Select all

x*a + (x*y)*b = x*(y+1)

We get:

Code: Select all

a = -b*y + y + 1

And if b=1, then a=1, so 100% of each signal (Carrier & RM) is the same as AM (Carrier + RM = AM).

Or easier:

Code: Select all

x+(x*y) = x*(y+1)

->

Code: Select all

x + x*y = x + x*y

what is True

[zerocrossing]

What's the best way to do Amplitude Modulation (AM) between two oscillators in MsoundFactory?

The best way I came up with is to generate a custom modulation source with one oscillator and modulating the volume of the other oscillator. That sounds pretty good with oversampling, but I'm hoping there's an easier way to do this.

The Merger module seems like an obvious candidate, but I don't see AM as an option there.

What about just 1 oscillator modulated by a LFO with 'Follow note frequency' enabled?

That’s how I do it.

[Held]

Mmm you are right!!

It's nice to have your experiments confirmed with math. Thanks.

What about just 1 oscillator modulated by a LFO with 'Follow note frequency' enabled?

That’s how I do it.

That adds a few more harmonics than normal AM since the volume control of the oscillator is logarithmic. (Compare the second screenshot with the first screenshot in my post above)

It can sound pretty good as well, so I'd consider it another option to play around with.

[MeldaProduction]

Use Merger module, that lets you use several algorithms for "messing 2 signals together", one of which is ring modulation, which is equal to amplitude modulation. It probably has lots of other names too

Simple example:

Code: Select all

$eNrFV81u4zYQnmSLYoFe+ggB0lMRQKbtJN7ThnHkrNE4diNvVj0y0kQmQpEGSblJDn2LPkIfpz33WKAv0FuPLSjJ8s-CiC2kqE5DzvdxON+Q0ggG52E4CFQm4x6LrNJPBq3lMjFAD4Hs0cNLoe6YMGN2lw-pxQVO7QRiyJ8-3tNb1IYrCW14+zXQQf+iP9Iq0SztTphM0JfsTiAQoCvTXWYxUZo-o3a+D99-nBqWTgWXiRsPuukUCZBfC6tZWa3KalfWcWWdVNZpZXUq611lkcbCXEQhizBkEYcsApFFJJKH8mNulQ74M-rMPIEh7c67o06rAUue5dkRZ1Ldcvyxq4RgU4Nxnix7vOoNz4WKHnICOaAjppkQKPgzs05cskevboKp4NZiviopK-DNz2drnua8Nn+9pyORJVyCWakwhEF2V3iqmWIYVLUPUGBkMZ4vQI7a5YGoWeDPcyxjmnlwoKED-gDkC3rNUgQzNBEXglmlgfYyIdZnD-J1zUNfAoHwnMmHBnifpVIc44+SGyWLvS6J-5r5BBM2RaAzJjKc1+DbMxqM-dHoxg-8MRDwPG853b2d0m0upZtbw8wC2a+b+WGAKbdKooH499-+Dv785auz-1eOvPpflnIMUCe4IkUx46rezbRGaV3ieQ1LVd6UVmCRCSD7tC+nme3LGB+Jw+XD3JkPh5ldcv-zgo4DFSOYGy6Tg1TFmSgu5usJ5rln6WqGL9-KxlHjP7uVbjPUWhY9EKBXKBM7cWfNlzMUyhWWGsOTKop-fTuv6n7FbNZmtmoz27WZx7WZJ7WZp7WZnRpMX84IhGONqRKqvJ9r99FhmltgWltg2ltgjrfAnGyBOd0C03kJU-Q6vpy9BLzqDcm61iuYRW1ycHMXcGsXcHsX8PEu4JNdwKe7gDtbg2+YjFWan1kmzb3SafnW3XjM33pzVrMWq1WL1d6R9R0+mYgJJDV5u+Z2i0JF3NYLukKuG3nNsVhkpNGYTONmALfR5BxlHG6EDFT8aYIoNgLGPL3TeNreCDjXyOyk0dwI8B+nbqNcSUI2goLMWOZ6mQ3+a2VxeH+-7r8UPMbyTbPq6SpptRICtfv6c5kIdN9xicK9h0IaWT5DpyDa4pfD9QIXOOMRDtCiNisN33ww1piXqp+yxLWEWSoNkDdh2Rw89S2mfXmvwKumAsssQniJUiN4YaGn24G2PJr3Ql5IhWsu7CQFL+whs5lG10mEZb8GZWsH61t5lTi5AMUx3Mu7l1GpjLP1FOiNW5vshwNmNX9cOAupmhB+4rGdDCAMVKYjdK0T3nNhURd-pZ7n-fQvMCrBQA==

[Held]

Use Merger module, that lets you use several algorithms for "messing 2 signals together", one of which is ring modulation, which is equal to amplitude modulation.

Thanks for the example. AM in MSF sounds great

[MeldaProduction]

[Korg Supporter]

Ring Modulation is easier to access in MPowerSynth.

[pervyinthepark]

But I can't make the powersynth as f**ked up