Flux imaging of original C64 floppies

[Supamax]

Hi,
I have a doubt regarding the imaging of original C64 floppies.
Using a 1.2MB 5,25" drive, should I use the "--adjust-speed 300" parameter or not?
I'm asking that because I made some flux images and noticed (analyzing them with HxC) that doing them *with* the above parameter leads to better/cleaner images.
On the other hand I read on some websites that a 360rpm flux image should be better for writing it back on floppy using a 1.2MB 5,25" drive. And a 300rpm flux image should be better for writing it back on floppy using a 360KB/720KB 5,25" drive.
Also, when I use the "--adjust-speed 300" parameter, it would seem that the disk is not really read at 300 rpm but the track data is scaled from 360 to 300 rpm.

Also, according to the FluxEngine and Disk2FDI websites, one should always image some disk formats (e.g. C64 ones) at 300rpm since the original drives spin at that speed...
http://www.oldskool.org/disk2fdi/525HDMOD.htm
http://cowlark.com/fluxengine/doc/driveresponse.html

On the FluxEngine website I read:
"--flux_source.rescale=X, --flux_sink.rescale=X
When reading or writing a floppy on a drive that doesn’t match the original drive RPM, the flux periods can be scaled to compensate.
For example, to read or write a PC-98 1.2MB (360rpm) floppy using a 300rpm floppy drive:
--flux_source.rescale=1.2 --flux_sink.rescale=1.2"
Can this be done with the GW.exe program?

[Supamax]

For example, this is the Alien Storm disk imaged @ 360rpm (without using the 300rpm parameter) with my Epson SD-680L drive:

[Supamax]

... and this is the same disk imaged with the same drive using the "--adjust-speed 300" parameter:

[Supamax]

I asked the same questions on the Greaseweazle group on Facebook (https://www.facebook.com/groups/greaseweazle) and Keir Fraser gave me some interesting answers .
If needed, I can summarize here.

[rhester72]

Originally Posted by Supamax

I asked the same questions on the Greaseweazle group on Facebook (https://www.facebook.com/groups/greaseweazle) and Keir Fraser gave me some interesting answers .
If needed, I can summarize here.

Please do!

[Jeff_HxC2001]

You can also set the internal HxC variable FLUXSTREAM_IMPORT_PCCAV_TO_C64CLV to your RPM speed (300). This is in the settings -> Internal parameters window. See the attached screenshot.

[Supamax]

Hi Jeff,
I played a little with that variable but the imported KF RAW dumps (I tested 1-2 of them, I'll do more) don't show changes in the Dummy Disk visual representation... (the red/green zones)
Maybe I'm doing something wrong.

The RPM speed must be the effective speed of the dumping drive, right?

[Jeff_HxC2001]

Originally Posted by Supamax

Hi Jeff,
The RPM speed must be the effective speed of the dumping drive, right?

Yes.


Send me this dump too i will have a look.

[Supamax]

Originally Posted by Jeff_HxC2001

Yes.

Ok.

Send me this dump too i will have a look.

Sure.
Some days ago, in order to simplify things, I took 3 non-protected (DOS) C64 floppies from my mother's home.
I'm going to do dumps of those three, so there will be no protections in the way.
Maybe it's better to send those to you, before sending the Alien Storm one, which is protected... what do you think?
I'm just finishing some dozens ZX Spectrum +3 dumps and then I'll do them.

I have three 5,25" floppy drives:
- TEAC DD 720KB 80 tracks 300 RPM (very rare, I used it with the Amiga in the nineties - connected as external drive and using a DF0/DF1 switch in conjunction) to save on floppy disk prices )
- TEAC HD 1.2MB 80 tracks 360 RPM
- EPSON HD 1.2MB 80 tracks 360 RPM

I hoped the best one could have been the TEAC DD, which natively spins at 300 rpm (so I wouldn't have to worry about speeds) but I found out that the EPSON is absolutely the best one in this case.