Page 2 of 4

Re: Extremely important info for the sound of piano samples!

Posted: 05 Apr 2013, 20:56
by Mr_-G-
Here is a 180 degree sample of a sine wave.
phase180.wav
(518.66 KiB) Downloaded 366 times
We could try making a nsmp and playing it in stereo and mono to test whether this also applies to the synth samples.
When mixed to mono in audacity you end up with (almost) silence.

Re: Extremely important info for the sound of piano samples!

Posted: 17 Apr 2013, 16:33
by RobertoBennet
Mr_-G- wrote:Case 1: Mixer with only mono channels
Connect left output to one channel and right output to the another (let's say Ch1 and Ch2).
Then move the PAN setting in Ch1 all the way to the left and the one in Ch2 all the way to the right.
That makes the outputs go to the right output (speakers).

Case 2: Mixer has some stereo channels
Usually the stereo channels are labelled Ch4/5 or similar and have a pair of inputs in that strip instead of one)
Connect left from kbd to L input and right to R input in that stereo strip.
The PAN dial should be pointing to the middle.
Thanks for the helpful reply,can you post any video tutorial regarding this,It will be beneficial for me as I am a learning stage. :yourock:

Re: Extremely important info for the sound of piano samples!

Posted: 20 Apr 2013, 22:58
by whitenoise
So what's the final verdict? Is the phase issue resolved by mono option or not?

Re: Extremely important info for the sound of piano samples!

Posted: 21 Apr 2013, 17:41
by bluesbaba
yepp..a verdict would be good folks!
i for one use mono piano a lot,but my biggest problem is soloing!the right side(above middle C) of the sound is to week compared to the Bass side!!!!!!!

Re: Extremely important info for the sound of piano samples!

Posted: 21 Apr 2013, 22:28
by Mr_-G-
OK here is my suggested 6 step test to find out whether the Mono switch does any magic.

0. Make some midi track to guarantee the performance is always the same.
1. Record in stereo (let's say audacity) a piano where you want to investigate phase cancellation.
2. Record the same in "Nord Mono" as a different track.
3. Take the stereo recording from [1] and make it mono. (Tracks>Stereo track to Mono). This is just sample mixing in audacity.
4. Now compare [3] (just mixing) and [2] (Nord mono). This could be just a listening test or a more complex one (power spectrum, spectrogram, etc).
if (the two sound the same) then
(the switch is just a wave mixing)
else
(the switch does some phase magic and should sound better)
5. Please report here your results.

Note that this only tells you about that recorded sample, same as the sine wave example I posted earlier.

Re: Extremely important info for the sound of piano samples!

Posted: 22 Apr 2013, 00:32
by Mr_-G-
Well some update...
Just load this sample
SineOutOfPhase.nsmp
Stereo sine wave at 180 degrees phase
(152.97 KiB) Downloaded 693 times
which is a sine wave at 180 degrees phase.
If you play it through a stereo amp you will hear it, but if you switch from stereo to mono, the sound vanishes. That means that the channels cancel each other and the circuit does not or cannot (in this extreme example) compensate for this.

This makes me think whether the Keyboard Magazine comment posted earlier about clever circuitry might not be correct, and the mono switch just mixes the two channels. Otherwise I would expect to hear something preventing the phase cancellation, and I do not.
Or maybe this is a too extreme example and with other waveforms it makes a difference, I just do not know.

Other interesting facts from that sample is that I was not able to apply many of the effects (chorus, phase, reverb). I am guessing here that those rely on "out of phase" modulation processing.

Of course the phase cancellation is a problem of the recording itself; it might be possible to move microphones into different positions and end up with a recording that (when converted to mono) does not suffer from this problem (same as I could change the phase of the sine wave). Anyway, I am suspecting that a real time method that does just that might be quite complex.

Re: Extremely important info for the sound of piano samples!

Posted: 25 Apr 2013, 10:50
by Florian
Yes, the magic Button just makes a monomix. I cannot imagine something that deletes all the phasing issues of a stereo recording by pressing a button.I have done a lot of stereo recordings with grand pianos and uprights as xy ab and ortf. The problem is also that the phasing issues differ from note to note.
The simple solution for a mono sound that will not have any cancelation is a mono recording session with one mic. This leads to a little to much midrange but this is not bad for a mono piano sound which have to cut thru a band sound. A strong tone with a long sustain is also recommended for live playing, because the nords seems a little bit harpsichordy in a louder band situation. The nord upright sounds like the queens seems to work a little better in a live band situation . The problem with grands and recording is that the tone seems to be shorter on the recordings. Perhaps because of the reduced dynamics.
As a sound engineer in germany i can tell that 98% of all pa systems here are stereo and in my eperience in the last 15 years i have never put a keyboard or a piano mono. But the problem is the monitoring. More often than not the piano player just have to play with one wedge. So the engineer has to decide whether to put the right or the left or both hands to the wedge. And this is where a lot of phasing issues appear. Allways ask the engineer to put just one channel into the monitor... it will sound better. The problem with thin piano sounds in live situations depends on the mix and on the instruments. Toto for example always had and have a thin piano sound in live situations no matter if its korg m1 or nord piano. Another issue is that the majority of the audience is not center infront of the stage. Even a lot of people are standing outside of the stereo image and they only hear the outside fill system which is allways mono. So all the overheads and tom mics from the drums stereo guitars and nord pianos and everything else is mono there. So a lot of sound engineers try to make a good mix which is not too much stereo because if it sounds good in mono it will not change too much wherever you are listening.
Back to our problem with the nord piano sound which is wonderful and mindscaping on headphones, amazing on good stereo pa systems but crap on bad or older systems and really awful in mono.
As advise from someone who plays pianos and works as a sound engineer: dont use too much reverb, dont try to fix your monitor sound with the eq because you always change the pa sound also. By the way: always try to cut with an eq first because if you boost you also add phasing issues. Try to compress the piano. This is good for the sustain. Almost every engineer use a compressor on keys to get rid of the hard dynamics. Try uprights in live situations with a louder band. Use a grand sound if you are playing alone or in a jazz band.
Nord Forever :keyboard2:

Re: Extremely important info for the sound of piano samples!

Posted: 25 Apr 2013, 11:48
by Frantz
Thank you all for this topic.
I won't forget to check the pan for my 2 channels on the mixer next time ;)

Re: Extremely important info for the sound of piano samples!

Posted: 25 Apr 2013, 17:20
by bluesbaba
Florian..thanks a lot....Great insight and info!!!
Last question he he : The Mono button.... Use or not use?
Two bears or not two bears ? Shakesbear :thanks:

Re: Extremely important info for the sound of piano samples!

Posted: 25 Apr 2013, 18:27
by whitenoise
Agree that in the majority of cases the audience can hear only mono sound even if the PA is stereo. If you run stereo signal into PA you may get even worse sound as the venue itself creates phase shifts due to sound reflection. The temporary solution would be to use one of the audio outputs. I guess it's better for piano to use the right one so you get more higher range. You may always boost low freq by equalizer. In the mean time Clavia can use the samples they created to make mono samples. They just need to remap the keys sounds and boost the ones that are most distant from the mic.

PS The sound you get with mono button and stereo signals mixed in your mixer is different. I guess the mono button still changes the sound. But doesn't make it better unfortunately.