Hi,

Thanks Alexandre this equation was exactly what I needed for my purposes. I also didn't realize the output from env~ is Db already, thanks all!

Cheers,

Chris.

On 4/11/23 4:28 pm, Alexandre Torres Porres wrote:

I don't think I get it, but the value change in the multiplier would be a ratio. Say you go from 0.5 to 1, that's like multiplying it by 2, so you have to convert this ratio to a dB change, formula is db = log10(ratio) * 20, and a ratio of 2 is a 6.0206 dB increase.

Em sáb., 4 de nov. de 2023 às 05:15, Chris McCormick <chris@mccormick.cx mailto:chris@mccormick.cx> escreveu:

Hi,

Hopefully this elementary audio question is not too stupid.

If I have some signal source how I can I measure the relative change in
Db when some change is made to the signal? E.g. if I have an [osc~ 440]
going into a [*~] and I change the multiplier, how can I measure the
output from that and determine relative change in Db when I change the
multiple?

Also does this even make sense on Db scale?

Thank you!

Cheers,

Chris.


-- 
https://mccormick.cx/



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• Andy Farnell padawan12@obiwannabe.co.uk [2023-11-04 09:49]:

[...]

confused about what is the best way to do that, the choices being [samphold] and [env]. So I'd also be interested in the best (most accurate) answer.

Andy, [samphold] as well as [snapshot~] do give you the amplitude value of one single sample, which for audio signals is often in the range between -1 and 1. [env~] will give you an dBRMS value (the mean of all absolute amplitudes over a certain time window, converted to dB.

Was that your question?

I'rather be interested in the difference between [samphold~] and [snapshot~]. They seem to almost do the same thing to me.

best, P

Am 4. November 2023 10:05:22 MEZ schrieb "Peter P." peterparker@fastmail.com:

I'rather be interested in the difference between [samphold~] and [snapshot~]. They seem to almost do the same thing to me.

[snapshot~] does a signal->message conversion (so it's output will only ever come after (actually before, but that's nitpicking) a block boundary, whereas [samphold~] is a signal->signal object (which you can use to downsample (with a sample-and-hold algorithm, hence the name) your input signal at an arbitrary rate).

If you drive the [samphold~] object with a [phasor~] at block-frequency you about the same output as driving a [sig~] with [snapshot~] (but hey, both an [osc~] and a [phasor~] have comparable output when run at sr/2)

mfg.sfg.jfd IOhannes