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Re: Fading sound in and out

From: Chris Wilson <cwilso@google.com>
Date: Wed, 20 Aug 2014 11:21:43 -0500
Message-ID: <CAJK2wqUo111=FzP7iRrYUSmvTK6TXy3+kWM3MBA8dXS035gJcw@mail.gmail.com>
To: Chinmay Pendharkar <notthetup@gmail.com>
Cc: Yehonathan Sharvit <viebel@gmail.com>, "public-audio@w3.org" <public-audio@w3.org>
Actually, your problem is you're not setting the start point for the linear
ramp appropriately; you setValueAtTime(0) when the context is created, But
you need to additionally set it when the play or stop button is pressed (to
give it a start value and (more importantly) time for the ramp.  See

What's happening now is whenever the click methods are called, the start
time and value for the ramp is whatever the last schedule event was - e.g.,
if you loaded the page and waited three seconds, then clicked play, the
linear ramp will have its start point (value 0) set on creation - 3 seconds
in the past - and the end point is three seconds in the future (value 1) -
so it will immediately jump to 0.5, and ramp from 0.5 to 1 over the next 3
seconds, which is why it's not smooth enough.

I really need to write an explanatory article about how to use the

On Wed, Aug 20, 2014 at 9:43 AM, Chinmay Pendharkar <notthetup@gmail.com>

> Hello,
> You can look at using the exponentialRampToValueAtTime or setTargetAtTime methods
> instead.
> Human perception of loudness is logarithmic in nature, so exponential
> decays of loudness feel 'smoother' to us than linear decays.
> -Chinmay
> On Wed, Aug 20, 2014 at 10:29 PM, Yehonathan Sharvit <viebel@gmail.com>
> wrote:
>> Hi,
>> What is the best way to fade sound in and out?
>> I tried to achieve that by calling linearRampToValueAtTime (see a demo:
>> http://jsfiddle.net/viebel/9La05fg5/7/) on a gain node but the effect
>> was not smooth enough?
>> How could I make it smoother?
>> Thanks,
>> Yehonathan.
Received on Wednesday, 20 August 2014 16:22:10 UTC

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