Re: [PD] Relative Db measurement

[Chris McCormick]

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 > 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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Re: [PD] [PD-announce] Pd 0.54-1 released

[Linux ROUEN Normandie]

Thank you Peter, it's so simple ! 😉

Librement,
Joseph


Le 04/11/2023 à 10:00, Peter P. a écrit :

Dear Linux ROUEN Normandie,

* Linux ROUEN Normandie  [2023-11-04 00:27]:
[...]

Key is stored in legacy trusted.gpg keyring (/etc/apt/trusted.gpg), see the
DEPRECATION section in apt-key(8) for details.

Type
man apt-key
and search for the DEPRECATION section?

amicalement,
Peter
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Re: [PD] Relative Db measurement

[IOhannes m zmölnig]

Am 4. November 2023 10:27:35 MEZ schrieb "IOhannes m zmölnig" :

>If you drive the [samphold~] object with a [phasor~] at block-frequency you 
>about the same output as

 [...] you *get* about [...] 


mfg.sfg.jfd
IOhannes


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Re: [PD] Relative Db measurement

[IOhannes m zmölnig]

Am 4. November 2023 10:05:22 MEZ schrieb "Peter P." :
>
>
>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


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Re: [PD] Relative Db measurement

[Christof Ressi]

I'rather be interested in the difference between [samphold~] and
[snapshot~]. They seem to almost do the same thing to me.
The only difference is that [samphold~] is audio rate and [snapshot~] is 
control rate.


Christof

On 04.11.2023 10:05, Peter P. wrote:

* Andy Farnell  [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



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Re: [PD] Relative Db measurement

[Peter P.]

* Andy Farnell  [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



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Re: [PD] Relative Db measurement

[Peter P.]

* Chris McCormick  [2023-11-04 09:14]:
> 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?

Why not use [env~]? If its result changes, try a longer measurement
window. See the help patch.

best, Peter



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Re: [PD] [PD-announce] Pd 0.54-1 released

[Peter P.]

Dear Linux ROUEN Normandie,

* Linux ROUEN Normandie  [2023-11-04 00:27]:
[...]
> Key is stored in legacy trusted.gpg keyring (/etc/apt/trusted.gpg), see the
> DEPRECATION section in apt-key(8) for details.
Type
man apt-key
and search for the DEPRECATION section?

amicalement,
Peter



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Re: [PD] Relative Db measurement

[Andy Farnell]

Measure rather than determine (by calculating the change in the
multiplier) means resampling the signal, and I've always been a bit
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.


On Sat, Nov 04, 2023 at 04:13:15PM +0800, Chris McCormick wrote:
> 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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Re: [PD] Relative Db measurement

[Alexandre Torres Porres]

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 
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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[PD] Relative Db measurement

[Chris McCormick]

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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