View Full Version : probably a stupid question... beatmatching help.

10-26-2012, 10:57 AM
hey guys, I've been around DJF for a while, and I'm upper novice level, but I'm still pretty confused on one thing....

When I'm setting BPM on my Mixdeck (it has a BPM counter down to the first decimal that is pretty accurate.)ill be playing one sound and cueing the other setting the BPM, lets say the BPM reads out as 110 when i first load the song before i even hit play. ill hit play, and after about 10-15 seconds (depending on the song, this could take longer or shorter.) the BPM reading changes to something different, i wouldn't say drastically different, but usually like 5-7 BPM. this happens all throughout the song, in breakdowns the BPM changes, on drops, etc.

So here's the question, is my BPM reader inaccurate, is it glitched up, is it something to do with my songs, or are my songs changing BPM throughout the track? i read music and play a lot of instruments and rarely ever do songs actually change tempo in the middle of them.... does anyone else have this happen to them, and what is going on?

side note: i know, i know, i should learn to beat match and set BPM with just my ears, I'm working on it but its pretty hard, so I'm using this most of the time.

thanks for the help!

ben mills
10-26-2012, 11:08 AM
It probably just takes a few seconds to get an accurate reading. That said, you know what you need to do.

10-26-2012, 11:15 AM
yeah, i thought that too at first, but like i said the BPM changes once or twice throughout the track no matter what i'm playing, not just at the beginning.

ben mills
10-26-2012, 11:26 AM
Might just be inferior equipment.

ben mills
10-26-2012, 11:27 AM
But I don't know anything really about the Mixdeck...so who knows.

10-26-2012, 11:35 AM
yep i think my bpm reader might just be not that accurate. it stays true to the reading in proportion to the other deck, as in if i set both decks to 115BPM they will sync together perfoectly, and it doesn't even Drift unless i have them phrase matched playing together for long periods of time (over 2-3 minutes.) and then it barely drifts. this is just weird, it always reads a slower BPM at a more chill part of the song, as in the beginning vocal part of a dubstep track, and goes back to what it previously read as the bpm (IE 115 at beginning, 110 at vocal part, 115 at drop) after the drop, where the song appears to be going at a faster pace, but it doesnt' actually speed up or slow down the song when it does this, it just reads slower or faster. sorry this must be super hard to understand.... basically what i need to know is does anyone else's equipment do this, and is the song actually changing tempo when the BPM shows its going slower/faster or is the BPM reader just not super accurate.

ben mills
10-26-2012, 11:52 AM
Throw on a house track, or anything else with a 4x4 and see what happens.

10-26-2012, 11:59 AM
i usually mix progressive house, i was just using dubstep as an example. whenever it gets to the "chill" part of the song in the prog house track, IE. "i've got pressure, im in deep, seems everybody wants something from me. i was a lover, but now a thief, ill take your breath away and set you free...." on Pressure (alesso remix) where the quarter note kick isnt in there and neither are the synths, it drops down to a lower BPM again as if the song slowed down (but counting in my head while tapping my foot its still the same tempo as before...) and it shows up as the original BPM once it drops again and the quarter note kick starts going.

CC Ricers
10-26-2012, 01:27 PM
I see this happen in a lot of auto-beat counters, on Pioneer mixers, etc. If tracks are not pre-analyzed in some way, the deck would need to calculate the BPM in real time. As it "listens" to more of the song that number will fluctuate and eventually settle to a stable value. It's just a matter of statistics- the more samples you get the less your margin of error will be.

10-26-2012, 02:10 PM
If I had to guess, it seems like your mixdeck is doing the BPM calculations on the fly. On top of that, it would appear it's not analyzing the whole song for bpm, but it's just probably analyzing like the 15 seconds before and 15 seconds ahead of where you are in the song. On top of that its probably not recognizing the parts of the song with no kick drum. Meaning, when theres no kick drum, it just doesn't count those beats.

I don't know for sure, but I think rekordbox and ITCH both calculate bpm based on not the average, but one what the majority of the song is. So if there is a long stretch of consistent beats, it will calculate it off of that. Also, they don't analyze the bpm on the fly...the songs are analyzed completely before the bpm will even show up.

IDK anything about the mixdeck, but I think it's just your equipment doing its thing. Maybe it doesn't fit your needs... on the bright side, it'll force you to beatmatch by ear!

10-26-2012, 07:35 PM
This is pretty typical with on the fly calculations. If it's small fluctuations with 4x4s, it's just a typical Numark unit, if it's wild jumps in half-time or 3/4 tracks, it's just taking a rolling average, and getting tripped up by the omitted beat.