dB vs SPL, smoothing?

[Omxp]

Hi all,
I'm a new user and I saw some youtube tutorials, most of them is using dB as the measurement instead of SPL, I don't know how to change the graph to show dB instead of SPL! are they the same thing?
Another setting that I don't know what is the best pick is smoothing, which one is the best (some use 1/6 and some use psychoacoustic?

Thanks

 

[Wayne A. Pflughaupt]

Decibels is the measurement for sound pressure level (SPL). So yes they are basically the same.

As far as smoothing, “variable” seems to be preferred these days for a full range graph. For a subwoofer graph, use no smoothing.

Regards,
Wayne A. Pflughaupt

 

[Harrycr]

Re smoothing what do we hear?
For eq we use 6th smoothing?

 

[Wayne A. Pflughaupt]

Sorry, I don’t understand what you are asking.

Regards,
Wayne

 

[DanDan]

I think I may do Wayne.

"Re smoothing what do we hear?
For eq we use 6th smoothing?"

Old research came to the conclusion that 1/3 Oct was a good measure of the ear's resolution. i.e. raising or lower narrow bands would be inaudible.
I think we know better now, but 1/3 Oct is perhaps still a useful indicator of how the average human not really paying attention might discern audio.

Modes often have very narrow bandwidths, only a few Hertz sometimes. Narrow Q Eq is best to address these. But broader trends in the FR are best addressed but Eq filters with Q's as wide as the anomaly. Even shelving or gradually roll off filters are used for the broadest trends, e.g. HF roll off.

 

[Harrycr]

Yes you are right.
Has variable smoothing taken over 1/3 smoothing for everything?
Looking at the graph what determines a mode?

Regards

 

[DanDan]

I haven't seen it elsewhere. Var smoothing is provided by John in order to make the graphs more readable and meaningful. Previously we would turn on different smoothing when examining different ranges of the graph. 1/3 Octave 30 band Graphic Eq is still widely used in Live Sound work.
Best to Google Room Mode. On Waterfall graphs it is a frequency which stick up higher on the level axis and lasts a long time on the time axis.