# "no sound" with synth env\_curve default '2'

**URL:** <https://in-thread.sonic-pi.net/t/no-sound-with-synth-env-curve-default-2/8757>\
**Category:** Support, Help & Resources\
**Created:** [April 4, 2024, 11:02am UTC](https://in-thread.sonic-pi.net/t/no-sound-with-synth-env-curve-default-2/8757 "2024-04-04T11:02:40Z")\
**Posts on this page:** 5\
**Page:** 1

<div class="post-metadata">

**Author:** ![jonny](https://avatars.discourse-cdn.com/v4/letter/j/47e85d/32.png) [@jonny](https://in-thread.sonic-pi.net/u/jonny)\
**Post date:** [April 4, 2024, 11:02am UTC](https://in-thread.sonic-pi.net/t/no-sound-with-synth-env-curve-default-2/8757/1 "2024-04-04T11:02:40Z")

</div>

Hi! I’m not sure if this is just me, but when the `env_curve` is set to 2, I only get a click from the speaker (or silence).

Given _the default is 2_, **why does the sound differ when parameter is there** , eg something like `synth :dsaw, env_curve: 2` should sound same as `synth :dsaw`

Here’s the loop I made to see if I could hear different curves, prior to adding further logic (fx args etc), no synth is set here, so the issue is heard (for me) with the `:beep` default simple sine synth

```ruby

n = :e2
s = 8
env_curve = (1..7).to_a

uncomment do ### TEST
  live_loop :timbre do
    ##| use_synth (ring :tb303, :blade, :prophet, :saw, :beep, :tri).tick
    play n, release: s, cutoff: 100, env_curve: env_curve.tick
    sleep s
  end
end #####

```

- Without the envelope\_curve parameter (eg using default 2?) the sound is heard
- When env\_curve has legal value other than 2 (1-3,4-7) the tone is heard
- Appears to affect all synths (not extensively tested!)
- version 4.5
- Just me?
- Thanks!!

---

<div class="post-metadata">

**Author:** ![H\_Tachibana](https://avatars.discourse-cdn.com/v4/letter/h/e68b1a/32.png) [@H\_Tachibana](https://in-thread.sonic-pi.net/u/H_Tachibana)\
**Post date:** [April 4, 2024, 11:36am UTC](https://in-thread.sonic-pi.net/t/no-sound-with-synth-env-curve-default-2/8757/2 "2024-04-04T11:36:55Z")

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I was the same way.

```ruby
[1,2,3,4,6,7].each do |i|
  play 60, release: 1, env_curve: i
  sleep 2
end

```

 ![env_curve](https://europe1.discourse-cdn.com/flex017/uploads/sonic_pi/original/2X/4/4eff75d34c20224a9b7aaf34abe5de1a044ac732.jpeg)

---

<div class="post-metadata">

**Author:** ![Davids-Music-Lab](https://dub1.discourse-cdn.com/flex017/user_avatar/in-thread.sonic-pi.net/davids-music-lab/32/512_2.png) [@Davids-Music-Lab](https://in-thread.sonic-pi.net/u/Davids-Music-Lab)\
**Post date:** [April 5, 2024, 7:52am UTC](https://in-thread.sonic-pi.net/t/no-sound-with-synth-env-curve-default-2/8757/3 "2024-04-05T07:52:51Z")

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It’s also completely independent of release time.  
These are 1,10,100,1000 release:

 ![image](https://europe1.discourse-cdn.com/flex017/uploads/sonic_pi/original/2X/3/3a30762a8957b99c45935ce12c2c09123fb7c198.png)

---

<div class="post-metadata">

**Author:** ![coodge](https://avatars.discourse-cdn.com/v4/letter/c/74df32/32.png) [@coodge](https://in-thread.sonic-pi.net/u/coodge)\
**Post date:** [April 8, 2024, 4:38am UTC](https://in-thread.sonic-pi.net/t/no-sound-with-synth-env-curve-default-2/8757/4 "2024-04-08T04:38:56Z")

</div>

I’m not sure if I’ve got this all right but an env\_curve of 2 is an exponential curve. The absence of any attack, decay and sustain in most synths is due to their defaults being 0. This exponential curve starts at 0 hence the attack, decay and sustain parts have no volume , thus no sound, i.e. you’re releasing from zero. Try your examples with the rodeo or piano and you’ll hear a tone - the defaults are different in these and a few other synths.

---

<div class="post-metadata">

**Author:** ![Davids-Music-Lab](https://dub1.discourse-cdn.com/flex017/user_avatar/in-thread.sonic-pi.net/davids-music-lab/32/512_2.png) [@Davids-Music-Lab](https://in-thread.sonic-pi.net/u/Davids-Music-Lab)\
**Post date:** [April 8, 2024, 7:01am UTC](https://in-thread.sonic-pi.net/t/no-sound-with-synth-env-curve-default-2/8757/5 "2024-04-08T07:01:28Z")

</div>

The strange thing is that exponential is the default but it only happens when you specify the env\_curve parameter.

```ruby
play 60 #Sounds normal

play 60, env_curve: 2 #Only click

```