## RAM usage in the Interpolated Delay

Sound synthesis techniques, DSP and related mathematics

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### RAM usage in the Interpolated Delay

The interpolated delay requires to declare the amount of samples you need for the delay. Ok.
But How much PC memory will it take?

I would like to set it to execute at least 132300 samples (1/1D of a bar).. to be playable with a 2Gigabytes RAM PC...

That will probably require a simple calculation based of byte size, but I don't know where to start... please help..!

Acrobat
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Each sample is represented by a 32bit float, which is 4 bytes. So 132300 samples is 132300 * 4 / 1024 = 516.8 KB.

BTW, are you assuming a fixed sample rate?

-Andrew
Andrew J
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Andrew J wrote:Each sample is represented by a 32bit float, which is 4 bytes. So 132300 samples is 132300 * 4 / 1024 = 516.8 KB.

BTW, are you assuming a fixed sample rate?

-Andrew

ops, no, how will your calculation change at 192Khz, for example?
thanks a lot andrew, you're always ready to those sort of things...!

Hey, only 512K?
Mmmh now I'm think that I could simply create some silence in an audio editor and watch the filesize... oh and your calculation is x2 since I'm in stereo...

Acrobat
smaniac

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Well, you also have to take SSE into your calculation. SSE uses 4 channels, so each memory address in a code module is 32Bit x 4 channels. Which means at 44,1kHz sample rate, its real size is:

44100 sample/second * 4 float/sample * 4 byte/float = 705.600 Byte = ~700kB/second

MyCo
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Nice pickup Maik.

for me
Andrew J
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Well. I guess most of us has a couple of rams available or even more.......

Is this really an issue? Is there more to it?

Great calcs Andrew and Myco.
It's never to late to be late.....
http://martinrodensjo.smugmug.com/

aliasant
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aliasant wrote:Is this really an issue?

I think not a problem at all, and for any PC,
I just wanted to figure it out a bit,
what's the real deal, the weight on RAM addressing those MEMs...

I guess I can raise the amount far more than I was doing,
thx to u all, now it's all up to me re-calculating in my schematic..

Acrobat
smaniac

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FYI...

I use a 20 second (at 44.1 KHz) four channel delay in my long-delay projects.

I took the delay alone and made a VST (no controls, no GUI) and it added 19.9 MB to eXT's memory usage compared to the theoretical minimum of 13.4 MB. A null VST (no processing straight-through) made in SynthMaker adds 6 MB so there's very little unaccounted for.
oddson
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oddson wrote:FYI...

I use a 20 second (at 44.1 KHz) four channel delay in my long-delay projects.

I took the delay alone and made a VST (no controls, no GUI) and it added 19.9 MB to eXT's memory usage compared to the theoretical minimum of 13.4 MB. A null VST (no processing straight-through) made in SynthMaker adds 6 MB so there's very little unaccounted for.

oh yeah infact I was thinking I could ask u too, I remember your long-delay stuff...
I thought the "unaccounted" will be, in my case, also 2 free-running LFOs that should take some more (for the read-256.MEMs and a wavatable OSC with 40 waves x 2048 points... I'll take a look at thee situation...thx... I wondeer what's those 6MB more in your case.. boh! Maybe the "SM shell" itself...

Acrobat
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yes, I worried about this myself when i started making looper effects, Imagining that the memory usage would cripple any machine ... and I laughed when I calculated the actual usage.

tiny by modern standards.
a looper, some time ago

angstrom
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