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Hello
I have a question about the strange behavior of my audio input on my DP:
I am trying to use Ivory 2 connected with my DP, and I also try to use the DP internal speaker to reproduce the sound (instead of using a headphone)
My problem is that as soon as I plug the cable from my external sound card (a Berhinger FCA202) to the piano, I get a "buzz" sound from the internal speaker that increases with the DB volume button (I don't any buzz sound from my dp if no cable are connected)
The thing that is strange is that if I connect my sound card to my hifi system, I don't get this "buzz" sound....as well as if I use headphone
I previously had a Kawai CA93, and I had the same problem, I thought it was due to the internal DP amplification system, but I get the same trouble with my NU1 now...
It looks like there is an impedance problem between the sound card and the DP (and not with an HIFI system)...
This problem really disturb me while the piano sound of Ivory is so beautiful...

Anybody as an idea about what is the problem ?

Thanks,

The buzz is probably coming from the computer sound card.

Regarding the sound card ... Which output are you using? Headphone output or line output?

enzo, I expect the buzzing sound you are hearing is caused by a ground loop when connecting the instrument to your computer using a USB cable.

You can try plugging your computer into a different power socket (or is it the same socket?), or if you're using a laptop, tun on batteries.

If this does not resolve the issue, I would recommend a 'Hum Destroyer' product, such as this one:

http://www.amazon.com/Behringer-HD400-2-Channel-Hum-Destroyer/dp/B000KUD2G4

Best of luck!

Cheers,
James
x

Hello MacMacMac, I am using the line output, not the headphone output which is amplified.
Then I must increase the "gain" control on Ivory as it is the only way I have found for controlling the output volume

Hello Kawai James
I am using a desktop, an the DP and the computer are not plugged on the same wall outlet
but perhaps you are right, there is a loop through the sound card & computer & DP

Does adjusting Ivory's 'gain' control alter the tonal character of the sound? Can you not simply adjust the output volume of your computer using the software mixer (on Windows) or volume control applet in the menu bar (Mac OS)?

Cheers,
James
x

There is no volume option on my Mac for this sound card, no way to control the output audio volume
There is a button on the card front side, but it is only for headphone output volume
And yes, the "gain" control alter the sound a little
I will perhaps try the buzz remover you suggested

Ah, I see.

Just out of curiosity, why are you using the external sound card? Was there a problem using the Mac's built-in audio?

James
x

There is not audio output on the mac, only the headphone jack output, which is amplified.
And the sound was not good when trying to connect it to my HIFI system, while it is crystal clear with the external sound card..except for the DP...
But I think you may be right saying that is a ground mass problem as I get the buzz as soon as I plug the cable, even with volume set to 0 on Ivory and the volume output does not impact the buzz volume, but the DP volume really make this buzz sound increase

The easiest thing to try might be to plug everything into the same outlet or power strip.

Yes, that's almost certainly a ground loop, and I'm reasonably confident that the device mentioned above will resolve the issue.

Cheers,
James
x

Why do you think that I should plug everything on the same outlet ?
Indeed, the DP and the Computer are plugged in different outlet, while the Computer and the HIFI system are plugged on the same (but there is not USB cable loop there)

The Behringer HD400 that Kawai James suggested appears (according to its documentation) to use passive isolation transformers to create balanced outputs on 1/4" TRS connectors. If the noise reported by the OP is actually AC hum induced by a ground loop, an HD400 will likely solve the problem.

Note, however, that the AUX inputs on the NU1 appear to be unbalanced on 1/4" TS connectors (inferring from the owner's manual). Therefore, cable connections between the HD400 and the NU1 will remain unbalanced regardless what sort of cable is used, and still subject to picking up stray noise.

Yamaha must be aware of the possibility of noise at the NU1's AUX inputs because they implement a noise gate (!) on those inputs (see p. 28 of the PDF owner's manual) -- a notably poor solution. IMHO, they could have used balanced inputs to begin with and saved themselves the trouble, but that would have raised manufacturing costs by a few bucks.

I believe most manufacturers of DPs with built-in speakers (not just Yamaha) provide AUX inputs mainly for convenience, and not with high-quality reproduction in mind. I hate to say it, but if one really wants to do justice to a high-quality software piano like Ivory, separate monitoring is the best solution.

If noise remains after connecting an HD400, perhaps experiment with replacing or re-routing cables from the PC to the NU1.

In my experience, noise described as "buzzing" in analog audio connections to PCs and Macs often originates not in system grounding problems but in leakage of RF energy from poorly shielded components inside the computer being picked up by unbalanced cable runs. PC manufacturers are not designing their hardware innards with these use cases in mind, of course.

Kind regards,

Ben

I'm sure there are electrical engineers here who can provide a technical answer to that question.

At the moment I have my CP5 and job sound system set up in my living room. When I initially set up everything the only piece of equipment that was not on the same power strip was the CP5 and there was very noticeable hum. As soon as I plugged the piano into the power strip in my rack case (which supplies the power to everything in my system) the hum disappeared.

I've written the following several times here in this forum - I lifted the ground plugs on every piece of my equipment (except for the power amp) and everything is plugged into the same power strip. Every since I did that my system is extremely quiet. (I have also confirmed with a continuity check that every piece in my system shares a common ground.)

I am not sure that would help the discussion (as I am not an electrical engineer), but I tried 2 things:
- first: I plugged my DP on the same outlet than my computer => no differences, still same buzz
- second: I unplugged the USB-Midi cable from DP to computer: the buzz disappeared
I can conclude that the problem origin is not the sound card, but a "loop" as said before.
Now I am not sure I understand the explanation about using same outlet and common ground.

So, I have ordered the hum destroyer, and we will see...

Please keep us updated on your progress.

Cheers,
James
x

Does the USB-MIDI cable run side-by-side or bundled together with the 1/4" audio cables? If so, try physically separating them.

B.

About 30 years ago I ran into a hum problem that baffled me for at least a few minutes. It turned out that the synthesizer, and more importantly, the power supply of the synthesizer, was too close to the unshielded workings of the Rhodes directly underneath it. Once I lifted the synthesizer a few inches away the hum magically disappeared.

I'm sure I first tried reversing the power plugs and switching out the audio cables. I never forgot that.

Usually when using USB (for MIDI etc) in conjunction with a standard audio output of a laptop/PC , you really need to use a ground-loop killer as described. Additional noise etc may come from bad cabling and/or a below average quality of the input of the instrument.

In my setup I use a ground loop terminator, a passive volume controller and well shielded cables. I have just a little noise (not too much; its OK), but the sound isn't very good (unclear, stressed, small, bit compressed). Perhaps we expect too much from the audio inputs of DP's as someone mentioned here before. But I rather had known that before buying my DP with the intention to really use the audio input for my SW piano etc.

Hello JFP
I have two questions: What is a passive volume controller ? (sorry if it is a silly question)
and what is your DP ?
I don't think the DP audio input is a low quality component, I think, as said before, the problem is more coming from the computer side (internal interaction between the USB in cable and Firewire out ??? )