I just found this website and i do hope i will find the answer of my question... i have a sp 404 since a few weeks and i have a problem that haunts me i don't know if it's "normal" , when i work on a loop in (for example) garageband set at 150 it plays it correctly, it is a "perfect loop", but when i import it to my SP 404 by using a CF Card the BPM is then set at 74 instead of 75 , (74 x 2 = 148 , 75 x 2 = 150) so the loop isn't perfect and i get a horrible gap of silence (about half a second) at the end of the loop...

Could someone tell me how i could resolve this problem... I'm sure there is a way but i looked for other methods and there is no way to do it correctly...

could you not jus tap tempo/manualy set the bpm and sample your loop??

All you have to do is delete the silence at the end of the sample.
To do this: fixate the end point untill the bpm is 75 and the sample loops perfectly. Then trunicate the sample. If you don't know how to do any of this, look at the manual.

also, the bpm read out isn't always correct, are you trying to sequence it into a pattern or just turning on the loop button??? if you are turnin on the loop button you should just be able to adjust the start/end points so that the silence isn't there, an easy way to set the end point where you want it is to put on reverse and keep hitting the pad while bring back the end point little by little, that way you can hear when the blank air is gone and it is ending right where the sound ends

Are you sure the GB project is running at 44.1Khz and not 48Khz?

Anyway, when making loops in software, you have to be careful how you prep and export it.
If you have only the loop area selected and bounce it to a new file, it will have it's boundaries set in the right places. If not the file may still contain audio outside of the loop points and the 404 won't know where they are. Note that most software uses loop point info written into the file and does not truncate it unless you select the exact bars and export or bounce only that selection to a new clip or file.

Safest thing to do I find is to set the DAWs snapping (usually in an "Edit" menu) to Bars and turn off "snap to zero crossings". Split (trim) at both ends of the loop on the bar lines and delete the leftover edges. Then zoom in and put a very quick fade in and out at the ends (to remove any glitches from any sharp edges). Now export the loop and you get a file that should be ready to go in the 404.

The 404 BPM is calculated from the number of samples in the file. The result should the same as the DAW had. Maybe a bit of error from rounding up the calculation, but that shouldn't be enough to affect the BPM displayed, unless someone's got their math very wrong!

Jim

Most likely, Jim Y hit the nail on the head with this one. You probabaly just didn't zoom in close enough to see where your true end point was before you exported.

If that doesn't work I would go with ZomB's advice of adjusting the end point until the BPM changes.

But, that idea about reversing to get your end point right...that seems like a brain-banger, as far as my 404SX...I personally feel disoriented by what comes through the speakers while adjusting end/start point. I realize it's trying to help me by repeating the "seam" area, but it's a brain-banger on my ears to try and follow what is happening there w/o a more complex digital display.

Hi
I know this is an old post but I thought I'd add a note about how the SP404 appears to calculate the BPM.
Whilst what others have said is correct in that it is the length of the sample that is used to determine BPM, and therefore a poorly trimmed sample will mess up the calculation there is another issue (feature) that has an impact on this.
It appears that the SP404 assumes an even number of bars in longer loops. So if you export a long sample (say 9 bars at 128bpm) then it incorrectly finds the BPM as being 114bpm. After doing some calculations on this I figured out that it was calculating the BPM of the sample had been 10 bars. If you make the number of bars an even number it seems to fix this.
If you are dropping in one or two bar loops then the SP404's default option for half/double BPM resolves this, but if (like me) you are putting longer loops on for example a whole vocal chorus then it appears they have to be in even bar lengths.