float to and from frequency

[DaveyM69]

I've double checked the displayed results for those values and they are correct. All the spec says is:

logf [20.000, 400.000, 101] Hz

which means: log float with a range of 20-400Hz, 101 valid steps

Dave
Binging is like googling, it just feels dirtier. Please take your VB.NET out of our nice case sensitive forum. Astonish us. Be exceptional. (Pete O'Hanlon)
BTW, in software, hope and pray is not a viable strategy. (Luc Pattyn)

[Sascha Lefevre]

I'll give it another thought tomorrow. Maybe someone who's more talented in math will solve it in the meantime ;)

If the brain were so simple we could understand it, we would be so simple we couldn't. — Lyall Watson

[Mycroft Holmes]

Frame the problem as a puzzle and drop it into the Lounge, I've seen a number of them get some detailed responses as long as they don't consider it a coding question you might get away with it :laugh:

Never underestimate the power of human stupidity RAH

[Kenneth Haugland]

Hmm, is this what you are asking? Generating a logarithmically spaced numbers[^]

[DaveyM69]

Brilliant find Kenneth! I have tweaked the C# method on that page to:

float[] logValues = CreateLogValues(20, 400, 101);

public static float[] CreateLogValues(float minimum, float maximum, int valuesCount)
{
double logarithmicBase = Math.E;
double logMinimum = Math.Log(minimum);
double logMaximum = Math.Log(maximum);
double delta = (logMaximum - logMinimum) / (valuesCount - 1);
double accumulatedDelta = 0;
float[] values = new float[valuesCount];
for (int i = 0; i < valuesCount; ++i)
{
values[i] = (float)Math.Pow(logarithmicBase, logMinimum + accumulatedDelta);
accumulatedDelta += delta;
}
return values;
}

which is a good start. I should be able to sort the rest from here :) Thanks :thumbsup:

Dave
Binging is like googling, it just feels dirtier. Please take your VB.NET out of our nice case sensitive forum. Astonish us. Be exceptional. (Pete O'Hanlon)
BTW, in software, hope and pray is not a viable strategy. (Luc Pattyn)

[DaveyM69]

Thanks for your help Sascha - I've got a solution, see my response to Kenneth below :thumbsup:

Dave
Binging is like googling, it just feels dirtier. Please take your VB.NET out of our nice case sensitive forum. Astonish us. Be exceptional. (Pete O'Hanlon)
BTW, in software, hope and pray is not a viable strategy. (Luc Pattyn)

[DaveyM69]

Ha ha! I don't think I'd be that brave ;) Nearly there now thanks to Kenneth's find.

Dave
Binging is like googling, it just feels dirtier. Please take your VB.NET out of our nice case sensitive forum. Astonish us. Be exceptional. (Pete O'Hanlon)
BTW, in software, hope and pray is not a viable strategy. (Luc Pattyn)

[Kenneth Haugland]

I have education in acoustics, were this comes up quite frequent :)

[Kenneth Haugland]

Ah, you should be careful though, LogE and Log10 gives you quite different results! And log10 is the one that is used in acoustics. I would know, I have a Masters degree in it :-D

[DaveyM69]

I'll keep my eye on it for other parameters that use the logf type. For the 20-400HZ one Math.E is giving the correct result. Thanks for the heads up.

Dave
Binging is like googling, it just feels dirtier. Please take your VB.NET out of our nice case sensitive forum. Astonish us. Be exceptional. (Pete O'Hanlon)
BTW, in software, hope and pray is not a viable strategy. (Luc Pattyn)

[Sascha Lefevre]

DaveyM69 wrote:

Thanks for your help Sascha

Let's call it an attempt ;) Good to see you got a solution - I'll take a look at it myself, might come in handy some time. cheers, Sascha

If the brain were so simple we could understand it, we would be so simple we couldn't. — Lyall Watson