Share your knowledge on these two classic MPCs
By JAYCEE3K Sat Jun 07, 2014 3:13 am
Hey yall, everything was fine just a week or two ago. I made a kit sampling some drum sounds into the 3k and everything played back just fine when testing. Now, a couple weeks later all of a sudden, the bottom seems to be missing from these same drum sounds when i play them. I tested my speakers by running a Aux from my cell phone into the speaker, and played a couple beats i had from there. The lows were all there, and the sub was thumping a bit more. When i hook the Aux out from the 3k and into these same speakers, all the Kick drums sound as if the lows have been EQ'd out significantly. It sounds like someone turned a nob to the bass all the way low, there's only a bit of bottom to the kicks. Any ideas as to what's causing this? Not sure if i'm just imagining this but last time i sampled from a source i remember a pretty much identical sound when playing back. I don't remember having an issue with samples sounding like the lows were stripped from them when playing back from the 3k.

Thanks
By JAYCEE3K Mon Sep 22, 2014 6:14 am
Thanks Clint...tried that, but doesn't appear to be cause of the problem...

The problem is i believe, now that i noticed, the machine is not capturing the full fidelity of the sound when sampling into it. The best way i know how to describe it is that when i sample into the machine through an aux cord from my pc speakers into the left record input of the mpc, two things i notice: 1) the DB levels are very low when monitoring into the mpc while recording even though i turn my speakers way up as well as the Record Level knob. 2) on playback, what i just sampled sounds distorted, flat, no low range, and is missing the full fidelity of the original sound.

The temporary solution i have found is to pull the Aux cord running into the mpc about halfway out till i hit the 'sweet spot' and now the mpc captures the full sound. Ever had headphones that one side (either left or ride side) went out when fully plugged in, but when pulling the cord halfway out you now are able to hear sound from both sides?? It appears that my mpc is having this issued when recording in it's only picking up one side when the aux cable is fully plugged in. :?

Can anyone tell me what's going on here?
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By SimonInAustralia Mon Sep 22, 2014 8:53 am
Your PC speaker aux output is an unbalanced stereo signal, it sends the left channel of the tip, the right channel on the ring, and the ground on the sleeve, that is called a tip/ring/sleeve (TRS) plug/socket.

The inputs on the MPC are expecting a balanced mono signal, with a positive (+) polarity (or 'hot') version of the signal on the tip, a flipped negative (-) polarity (or cold) version of exactly the same signal on the ring, and ground on the sleeve.

When you send an unbalanced stereo signal on a TRS connector into a balanced mono TRS input on the MPC, the unbalancing circuitry in the MPC flips the polarity of the right side signal on the ring, adds that flipped right side signal from the ring to the left side signal from the tip, and sends that into the MPC.

Since it is flipping the polarity of the right side of the stereo signal, and adding it to the left side of the signal, thinking it is a balanced mono signal, anything panned centre in the stereo image will be cancelled out, anything panned off centre will be cancelled out to varying degrees, depending on how far from centre it is panned.

You need to use the correct cables, maybe a 1/8" TRS to 2x 1/4" TS cable, like this...

Image
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By SimonInAustralia Wed Sep 24, 2014 5:15 am
blackbeard wrote:Could he pull the trs out a bit to get a connection? Works when I am in a pintch, but not best practice

Yep, plug it in to you feel the first 'click', so that the tip of the plug is connecting to the ring terminal in the socket.

Then you don't have two signals going into the balanced input, and don't have the problem of one being flipped and cancelling out the other.
By JAYCEE3K Wed Sep 24, 2014 11:56 pm
Wal Martian wrote:
JAYCEE3K wrote:pull the Aux cord running into the mpc about halfway out till i hit the 'sweet spot' and now the mpc captures the full sound.

Simon is right, get the proper type of cables and you should be good.


about to look for some online in a bit...

SimonInAustralia wrote:
blackbeard wrote:Could he pull the trs out a bit to get a connection? Works when I am in a pintch, but not best practice

Yep, plug it in to you feel the first 'click', so that the tip of the plug is connecting to the ring terminal in the socket.

Then you don't have two signals going into the balanced input, and don't have the problem of one being flipped and cancelling out the other.

needless to say, it just occur to me i have a good bit of drum sounds that at the time of sampling, i had the aux chord plugged in fully. although some of the kicks did sound suspect, i didn't detect a major difference in quality on playback for whatever reason.maybe it was luck (they weren't panned as much)..but now im thinking some information was lost though, and i should probably re-sample those. :Sigh:

on another note, does using cables that go from 1/4th In. to 1/8th compromise signal in any way worth making note of, in your experience?
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By SimonInAustralia Thu Sep 25, 2014 1:01 am
JAYCEE3K wrote:on another note, does using cables that go from 1/4th In. to 1/8th compromise signal in any way worth making note of, in your experience?

The actual 1/8" connector does not compromise the signal.

It is the electronics feeding the connector that give it the bad name, as it is used for laptop audio I/O, which is usually not very good quality, and other small devices where available space prevents the use of 1/4" connectors.
By blackbeard Thu Sep 25, 2014 2:04 am
SimonInAustralia wrote:
blackbeard wrote:Could he pull the trs out a bit to get a connection? Works when I am in a pintch, but not best practice

Yep, plug it in to you feel the first 'click', so that the tip of the plug is connecting to the ring terminal in the socket.

Then you don't have two signals going into the balanced input, and don't have the problem of one being flipped and cancelling out the other.


Wow, I feel like a retard, didn't notice this was already mentioned by the OP. :WTF:
By JAYCEE3K Tue Sep 30, 2014 7:42 pm
SimonInAustralia wrote:
JAYCEE3K wrote:on another note, does using cables that go from 1/4th In. to 1/8th compromise signal in any way worth making note of, in your experience?

The actual 1/8" connector does not compromise the signal.

It is the electronics feeding the connector that give it the bad name, as it is used for laptop audio I/O, which is usually not very good quality, and other small devices where available space prevents the use of 1/4" connectors.


so in the particular case of sampling from PC into the mpc through a 1/8" to 1/4" cable the sound quality won't be negatively impacted by the cable at all and just depends on the quality of sound coming from the PC?
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By SimonInAustralia Tue Sep 30, 2014 8:36 pm
Yep, not the cable/connector, just the low quality built-in audio circuitry found in PCs/Macs.

As long as the unbalanced stereo output of the PC audio output to balanced mono input on the MPC is correct.