Filter Envelope Amount

[DarkPlasma]

Ok, can someone help me out with this? Im confused as hell

Im having trouble understanding what the 'envelope amount' parameter does...In my TI manual, all it says is 'how much the filter envelope effects the cut-off'.

When I play around with the amount value, it seems like it takes the frequency range of the unfiltered sound and shifts it either positive or negative depending on the value of the amount.

So for example if I have a sound, and I put a LP at 250 Hz, and If the amount is set to positive, then it literally takes the range of 0 - 250 Hz, and shifts it higher, and then treats THAT range as the input for the filter envelope??

Can someone give me a concrete example, please?

Thanks!

[Feinstrom]

Try a short, snappy envelope. Lowpass filter.
Then compare 1. low cutoff/high ENV amount and 2. high cutoff and low ENV amount.

In the beginning I was confused about that as well, but once I found out it is one of the most important knobs on any synth for me.
It's best to have the ARP or sequencer running and work those knobs simultaneously to get the feel for it.

Cheers,
Bert

[OurDarkness]

Imagine putting your finger in a hole. Inserting the finger all the way, means env.amount = 100%, inserting the finger just a tiny bit means let's say 5%. Negative envelope amount means keeping the finger WAY out. Maximum distance is -100%. At 0 you are either going in or going out.

[Acid Hazard]

You'll see it used mostly on the Decay portion of the filter eg. It basically sets the amount of sweep the decay has on the filter. If you're doing a simple beeewwwww type of filter sweep, the Env Amt knob sets the amount of beewww you hear. A negative amount will swell up rather than down. But you can also achieve that with the Attack of the eg. If you have the cutoff all the way open, you won't hear anything, set the cutoff to about 50% and the env amt to about 20 or 30%. Then play with them, you'll understand.

[MarcB]

Imagine the filter cutoff level off is ground level... and the filter envelope ADSR is a hill , the filter envelope amount is how tall the hill is over ground level.

for eg. if your low pass fliter cut off is set to zero and your filter envelope amount is set to a low amount then the filter will rise and fall only a small amount , where as if it is set to a large amount , the filter will open nearly completely during the envelope.

clear as mud... as already stated.. fiddle with it along with your filter Attack/Decay/Sustain/Release settings to hear how it works

[Dave Peck]

No disrespect intended but when you say things like "seems like it takes the frequency range of the unfiltered sound and shifts it" and "the input for the filter envelope" it looks like you may have some basic misunderstandings of how analog synths and filters work.

It can't do anything to the 'unfiltered' sound, the entire signal is going through the filter, not bypassing it. And there is no 'input to the filter envelope', there is only an OUTPUT from the envelope because it is a control signal. The FILTER has an input and output (it is a modifier) and the ENVELOPE only has an output that is used to CONTROL the FILTER. Envelopes do not make or process any sound, they are used to control other things like filters and VCAs and oscillators that DO make or process sound.

See if this helps - set the filter to LOWPASS mode and set the Filter Envelope Amount control to zero so it has no effect. Now turn the Filter CUTOFF FREQUENCY control up & down manually and you will hear the filter slowly 'open' and 'close', allowing more high harmonics of the oscillators to pass through the filter when you turn it up (doing LESS filtering) and filtering out more harmonics and only letting the lower harmonics to pass through the filter when you turn it down. If you turn the cutoff frequency even lower than the fundamental frequency of the oscillators, you will filter out ALL of the harmonics AND the fundamental and you will get only silence.

Now - think of the envelope as a device that will turn this cutoff knob for you automatically, every time you play a note. Set the attack decay and release times to a few seconds and set the sustain level to about 50%. Now turn down the filter cutoff knob until you hear no sound or only a very dull sound with only the lowest harmonics. Now start turning up that Filter Envelope Amount knob and slowly play some notes. You will hear how the CONTROL SIGNAL from the Envelope is doing what you did a minute ago with the cutoff knob - it is slowly opening & closing the filter as controlled by the envelope. So, the filter envelope control determines how much the envelope will open and close the filter. But remember - the envelope is not making any sound. It is just controlling the filter cutoff for you and the oscillators are making the sound and the filter is altering that sound.

[Clem Snide]

Originally Posted by Dave Peck

See if this helps - set the filter to LOWPASS mode and set the Filter Envelope Amount control to zero so it has no effect. Now turn the Filter CUTOFF FREQUENCY control up & down manually and you will hear the filter slowly 'open' and 'close', allowing more high harmonics of the oscillators to pass through the filter when you turn it up (doing LESS filtering) and filtering out more harmonics and only letting the lower harmonics to pass through the filter when you turn it down. If you turn the cutoff frequency even lower than the fundamental frequency of the oscillators, you will filter out ALL of the harmonics AND the fundamental and you will get only silence.

Now - think of the envelope as a device that will turn this cutoff knob for you automatically, every time you play a note. Set the attack decay and release times to a few seconds and set the sustain level to about 50%. Now turn down the filter cutoff knob until you hear no sound or only a very dull sound with only the lowest harmonics. Now start turning up that Filter Envelope Amount knob and slowly play some notes. You will hear how the CONTROL SIGNAL from the Envelope is doing what you did a minute ago with the cutoff knob - it is slowly opening & closing the filter as controlled by the envelope. So, the filter envelope control determines how much the envelope will open and close the filter. But remember - the envelope is not making any sound. It is just controlling the filter cutoff for you and the oscillators are making the sound and the filter is altering that sound.

That's a great explanation.

By the way, I can see what the OP is trying to get at when s/he writes "seems like it takes the frequency range of the unfiltered sound and shifts it," despite it being incorrect.

[DarkPlasma]

ok i done figured it out.

all it is is the amount that the filter envelope modulates the cut off. THATS IT!! lol