Auto BPM Readout

Discussion in 'Audio Hardware' started by TwoTone25, Dec 28, 2016.

  1. TwoTone25

    TwoTone25 Member Thread Starter

    Location:
    Michigan
    Gemini Cdmp - 1400 has this feature but the Gemini Cdmp - 1500 says all over
    the advertisements it has BPM readout too. Can anyone tell me how to use this feature on the 1500 unit? Or what else maybe needed?
     
  2. TwoTone25

    TwoTone25 Member Thread Starter

    Location:
    Michigan
    Found out it doesn't have BPM readout, but the box says it does.
    If you know the BPM for a song, what is an easy way to find its pitch?
     
  3. TwoTone25

    TwoTone25 Member Thread Starter

    Location:
    Michigan
    Does anyone know how any cd player pulls the bpm's from the disc exactly? Does it get from the song itself or from an information file within the disc?
     
  4. Agitater

    Agitater Forum Resident

    Location:
    Toronto
    There is no relationship of any kind between BPM and pitch.
     
  5. TwoTone25

    TwoTone25 Member Thread Starter

    Location:
    Michigan
    Then why when you change the pitch the bpm changes also?
     
    sparkydog likes this.
  6. Agitater

    Agitater Forum Resident

    Location:
    Toronto
    CD players with beat counters have a firmware algorithm that analyzes pre-fetch sections of tracks by looking for repetitive low frequency amplitude peaks that continue for a certain period of time. The algorithm then sets the repetitive low frequency peaks as the beat and measures it against an internal timer to come up with a BPM. It's a simple algorithm that is easily confused by counter beats and other things.
     
  7. Agitater

    Agitater Forum Resident

    Location:
    Toronto
    You're confusing pitch with tempo. Slow the tempo and the BPM goes down. Increase the tempo and the BPM goes up.

    The pitch of a song is related to the key in which the music is written. Pitch has nothing to do with the speed (tempo) at which the music is played, and it has nothing to do with BPM.
     
    Strat-Mangler likes this.
  8. TwoTone25

    TwoTone25 Member Thread Starter

    Location:
    Michigan
    Ok, I see now. If that's true, then how do you locate the true pitch of a song?
     
  9. Agitater

    Agitater Forum Resident

    Location:
    Toronto
    That's the problem with dumb machines. When a band play something at a faster tempo, the pitch of the music and the key in which the music is being played don't change. By contrast, when a machine is used to play a given song faster, it increases in pitch also - the machine is not a musician.

    The original key and tempo of a recorded song can usually be found in the sheet music or the charts available online. Also, when first listening to a song on the CD player, zero or center the pitch or tempo control (however it's labeled) and you're pretty much guaranteed to get the correct tempo and pitch and BPM.
     
  10. Agitater

    Agitater Forum Resident

    Location:
    Toronto
    True pitch? I'm not actually sure what you mean. For dance beats, the tempo of a beat sample or pre-recorded track is whatever you want it to be when doing mixes and re-mixes. When mixing beats, samples and tones, speeding things up or slowing things down, you have to control pitch and tempo separately to prevent the music you're making from sounding weird or overly distracting.
     
  11. TwoTone25

    TwoTone25 Member Thread Starter

    Location:
    Michigan
    If a cd player has no tempo control setting, how do you know the bpm is playing correctly?
     
  12. Agitater

    Agitater Forum Resident

    Location:
    Toronto
    Because the CD player - all CD players - do the same thing so that prerecorded music plays back correctly.

    Some player makers somewhat inaccurately use the word "Pitch" for the speed control. That's because the pitch goes higher or lower as the speed is increased or decreased when using such players.
     
  13. Strat-Mangler

    Strat-Mangler Forum Resident

    Location:
    Toronto
    Tempo is the accurate term. That is what can vary on a turntable if the motor is defective, somehow. But on CDs, it doesn't work that way. The data stored on it doesn't have anything to do with audio as you know it which varies in tempo from slow to fast like a volume dial on an amp, for instance. In the digital world, whatever you're reproducing is set according to sets of 0s and 1s more akin to a light switch. Its a binary system of on/off info. So if the info isn't corrupted (as in scratches on a CD or corrupted clusters on a hard drive), the info will always play perfectly.

    That's why when you've heard issues with CDs, it's never that the music slows down or speeds up but rather it skips or doesn't play or stops playing. It either works or doesn't. Binary.

    CDs aren't an audio-based medium. They store data, whatever it is.
     
  14. Agitater

    Agitater Forum Resident

    Location:
    Toronto
    100% correct except for oddball players like the OP's Gemini Cdmp-1500 1U (sold through Walmart among other places) that actually has a pitch control. There are plenty of these sorts of gimmicky machines out there. They buffer everything in RAM after the internal DAC, then provide controls to manipulate the output.
     
  15. TwoTone25

    TwoTone25 Member Thread Starter

    Location:
    Michigan
    So, your saying the pitch control on my machine controls pitch and tempo at the same time?
    On my machine also, I can totally turn the pitch control off though too.
     
  16. TwoTone25

    TwoTone25 Member Thread Starter

    Location:
    Michigan
    If I turn picth control off, I hear nothing like skipping or not playing, but since you brought it up, one of my discs stops on this player even with pitch control off always at the same time but the cd plays perfectly on all other cd players.
    All my other cds play fine with pitch off also. Your guys opinion of what makes it stop and jump to the next track but other players play it fine?

    If a disc plays perfectly without setting tempo and pitch, is the tempo, key, bpm and pitch automatically set by the machine like if it was done manually exactly the same?
     
  17. Agitater

    Agitater Forum Resident

    Location:
    Toronto
    I have no idea whatsoever what that machine of yours is controlling. I don't own the machine, you do. So if you don't have the documentation for the CDMP 1500, go here:

    http://geminisound.com/wp-content/uploads/CDMP-1500-ProductManual.pdf

    You'll find the pitch-related controls described on pages 10, 11 and 12.
     
  18. Synthfreek

    Synthfreek Specialist In Yngwie & Ambient Worship

    Location:
    Austin, TX
    Machines and software have come a long way. Of course one can now increase the tempo without affecting the pitch.
     
  19. Strat-Mangler

    Strat-Mangler Forum Resident

    Location:
    Toronto
    OK. I write this with a sincere eagerness to communicate these concepts in a way you can understand them so please know I'm saying the following respectfully. You're all over the place with this. I'll try this way of explaining it one last time using an analogy.

    Firstly, forget about the Gemini for a minute. For the duration of this and the next paragraph, it doesn't exist. It's irrelevant in the explanation we're attempting to relay. It is also overcomplicating things on your end which translates into confusion. So let's start from the beginning.

    Digital info is data which is either legible or isn't. If it's legible, it will be reproduced accurately. That is what any normal digital playback operation does. It is like a regular on/off light switch. There is no slow or fast, higher or lower, nothing like that. None. Zero. It does not happen. It either is read accurately or isn't read at all.

    That machine of yours is a whole other animal. Why? Because inside are processors designed to MANIPULATE the data. And that data just HAPPENS to be audio. And the operations it can do HAPPEN to be about pitch and tempo. Whereas every regular CD player in the world is like a regular on/off light switch, this Gemini rack is more like a dimmer light switch. Not only can it do normal on/off reading but also manipulating what it reads and dim or intensify the "light" so to speak (referring to all those pitch and tempo options).

    There is no other possible way I can think of to boil down the explanation to a more fundamental concept than this. It sounds as if you've been exposed to zero knowledge on the topic whatsoever but acquired this Gemini rack and your whole experience with using CDs has always been with it which is why you're confused as you have no other experience or context to fall back on. Understand that machine is NOT a common CD player and is NOT what 99.9% of what people use when they refer to using CDs.

    Here's one last analogy. A regular CD player is like a program that just displays a picture you took. It doesn't do anything but just show it to you. The Gemini is like Photoshop. It changes colors, shapes, sizes, etc.
     
    panasoffkee likes this.
  20. TwoTone25

    TwoTone25 Member Thread Starter

    Location:
    Michigan
    I understand your point. I have used normal cd players for many years, until I got this one about a year ago.
    This is one of many cd players like it that have these features also, so they are all odd machines?
    The only odd thing it does is the pitch control feature, I just don't understand the purpose why its there at all really?
     
  21. Strat-Mangler

    Strat-Mangler Forum Resident

    Location:
    Toronto
    My father-in-law is the only other person I've ever known who has owned one such machine. It's not a CD player as it also reads MP3s and such. As I said, it is a much more complex machine with many more processors able to do much more than just playback what is called redbook audio (CD audio). Because of that, it is not called a CD player as it's QUITE a misleading term. It's a music player which also reads CDs. Hell, even the manufacturer calls it a "media player" because that's what it is. If you call it a CD player, people will automatically think of something like this.

    [​IMG]

    Notice the buttons on the right? Stop, Play, Forward to the next track, go Back to the previous track, and Stop. That's it. No weird esoteric functions of any kind. THIS is what is known as a CD player. What you have in the Gemini is a Media Player. A completely different animal. If the wrong term is used, nobody can blame people for thinking about a CD player and not a Gemini-type rack which isn't one.

    As for the pitch control feature, there are a few reasons I can think of. I play guitar and sometimes, musicians aren't tuned 100% correctly which means I'd have to tune myself to the song I want to play along with which is a pain when all I could do is adjust the pitch slightly so the *song* is now in tune with my current guitar tuning.

    Another is karaoke which is hugely popular, especially in Asian countries. People might want to sing a song that is in too high a key but if they lower the pitch so it's lower, they can now sing it.
     
    Last edited: Jan 10, 2017
  22. House de Kris

    House de Kris Well-Known Member

    Location:
    Texas
    You've asked a simple question, and I can't believe no one has actually helped you yet. You seem to be of the belief that if there is a pitch control, it must be used to correct incorrect pitch. This is not the intended use in this case. It is there, and labeled as such, to emulate turntables with a pitch control on them. Since the turntable is a simple mechanical device, the pitch control merely speeds up, or slows down, the rotational speed of the platter. When the speed is faster than normal, the pitch raises (all frequencies go up), as well as the beat of the music gets faster. Likewise, when pitch is lowered, the pitch goes down (all frequencies go down), and the beat of the music goes down. In the mechanical world of turntables, pitch and BPM (tempo) are always related. Your Gemini CD player does the same thing. There are other CD players where you can control pitch/BMP (as found in your Gemini), or only control pitch or BPM. This is something no turntable could ever do.

    Now, why do this? Most common use, and the audience of Gemini products, is for DJs to make a decent mix. Let's say you're playing a tune that has a tempo of 122BPM, and the next song you want to play is 118BPM. If you tried to do a smooth segue in this case, you'd end up with what's called a trainwreck. People on the dance floor would be laughing their heads off at your inept attempt to entertain. And, they didn't come there to laugh either, they came to dance. In other words, you've failed miserably. You would need to speed the slower 118BPM track up to 122BPM in order to have a chance of making a decent mix. But, having the same BPM is not a guarantee of good mixing, you would also need to line up the beats of one machine with the other. Most DJs do not need the assistance of a BPM counter to do their job, they develop it with practice, and lots of it. Going further, a DJ will select a tempo they want their mix to work at, and then force all the music their playing to that tempo. Using the examples above, perhaps the DJ is working at 121BPM for the night, the 122BPM would be slowed to 121BPM and the 118BPM track would be sped up to 121BPM. Magic, huh? No, just good skills by an entertainer.

    And yes, these things are indeed CD players.
     
    tmtomh likes this.
  23. TwoTone25

    TwoTone25 Member Thread Starter

    Location:
    Michigan
    Last question I have for now anyway. If you were just listening yourself at home and not DJ'ing a dance floor, if a track of ... bpm switches to a totally different bpm and you were to set the bpm accordingly for each song is that correct
    and what effect does that have? Or just turning pitch off totally is the only way to have standard playback?
     
  24. House de Kris

    House de Kris Well-Known Member

    Location:
    Texas
    The BPM display shows what the tempo is. You use the pitch control to move it to what you want. If "correct" means hearing it as presented on the CD, set the pitch control to '0', or just switch it off. The pitch control is just a tool, but you don't always have to use that tool. Just when the situation dictates.
     
  25. TwoTone25

    TwoTone25 Member Thread Starter

    Location:
    Michigan
    While thinking about what you said, it doesn't make sense why the pitch control if changed changes the bpm that shows the tempo, but changing the tempo or (bpm) does not change the pitch (it remains at 0.0, or where left at originally).
    How does one change the other, but doesn't work both ways?
     

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