Piano World Home Page Forums Our Most Popular Forums Digital Pianos - Electronic Pianos - Synths & Keyboards Yamaha DGX-640 + M-Audio BX5 D2

Hi there, having been annoyed with the vast sound quality difference between the built-in speakers and a pair of headphones (Koss UR-20), I spent several months googling up the best external solution and decided to buy a set of studio monitors. The BX5 by M-Audio had a good reputation and was at about the price I was able to afford. All excited I brought the nice black thingies home

Yet after connecting the stuff with a Y-cable, the sound is far from good. Some instruments sound sort of muffled, others seem to be cut (despite the volume being set to half both on the piano and the monitors) resulting in a strong unpleasant resonance of the monitors. Especially the lower C notes (C1, C2). Added to that is a constant hiss getting stronger along with the volume of the monitors.

Is it really so that a Koss UR-20 ($25) cannot be matched by a set of $250 monitors? Does anyone know what is the reason of the low sound quality and what can be done to improve it? Is it the Yamaha producing LQ sound or the monitors are not up to it?

When you say you connected the monitors with a Y-cable, what, exactly, were the connections? Are there line outs from the keyboard, or are you using the headphone jack? If the headphone jack, I think the output levels are different and you may be overdriving the monitor inputs. Also, are the monitors pointed at your head (ears)? Off-axis sound from monitors won't sound nearly as good.

Good question, forgot to mention that, sorry. Unfortunatelly there is no line-out, just the headphone jack socket (1/4") so the Y-cable has a stereo jack 1/4" on one side and two mono jacks 1/4" on the other.

I read about the monitor placement, yes, its a triangle. Also I tried putting the monitors on pillows to avouid resonance of the whole keyboard (they are placed on top of the keyboard, on the built-in speakers). For the volume levels, even with the monitors above half and the keyboard at half, its still not much loud yet already distorted (or at least having that resonance sound).

First thing to try:

. . . Reduce the volume of the Yamaha;

See if the distortion goes away. Then _slowly_ increase the gain of the loudspeakers.

Those speakers should be better than what you're describing. "Over-driving" is a likely problem, as suggested above.

. charles

If the 640 is like other boards in the DGX/YPG series, aren't there a couple different EQs buried down in the setting somewhere? There were two specific settings for external speakers on my YPG-535 and they made a huge difference.

True. The headphone socket becomes "line out" and is more suitable for the application described. Should still work, though on the h`phone setting . . .

Thanks for the tips, guys.

[See if the distortion goes away. Then _slowly_ increase the gain of the loudspeakers.]

I have just tried that. At low level it seems to be ok, but raising the volume even only of the monitors quickly produces it again. It is most audible with the F1 and C1 keys, they have so much bass I literally get sick. The keys in the upper half of the keyboard are fine even loud. Which makes me think its either their frequencies or bad samples on the Yamaha side. But why isnt it audible in headphones as well? There the piano sounds great, all the keys.

[..aren't there a couple different EQs buried down in the setting somewhere..]

Thats true, I tried those severla times. There are five of them predefined sets, two for speakers (booming even more, even more keys produce the over-reverberation), one for headphones and two for line out. Of these latter three the headphones gives best result and thats the one I have been using mostly. No more detailed EQ there.

Any more ideas to try?

This may not be what you like to hear. I bought a small system for playing my software piano on (I had the DGX630 whci has no line in sockets.

It simply was unable to accept the frequencies associated with piano. I got frequency buzzing which would not go away.

Had to sell it on . . . .

peterws: I was afraid I would hear something like that. Will have to try some profesionally recorded piano music. With commercial music (dance, pop, rock) the monitors do sound awesome though.

Let us know how it goes. . . but I`d try covering up the earth connection in your piano or sound system first. . . .

peterws: Okay, good idea, I will buy an extension cord and disable the earth pins, it may at least help with the hiss.

I own a DGX640 as well, and have been following this thread closely. I've been using headphones exclusively but have considered getting external speakers. What is the "earth connection"?

Thanks.

Nice to meet another owner If I understand it well, it is the earth wire in the power supply cord, I just bought an extension and am planning to cut this one. This wire is for safety only and might carry "noise" from other "noisy" sources in the household, especially computers. I am not sure how the outlets in USA look, but I reckon they have only two wires whereas Europe has three. If it is so, this is not a solution you could try.

On the other hand, it is customary here to have the earth (ground) wire connected to the null wire in many places in every flat so I guess this wont probably do anything..

I placed a small piece of paper (computer [paper thickness) around the earth pin so I didn`t need to cut anything! It solved the problem I had with hum from a sizeable external amplifier.

Ok so I tried disabling the earth wire using a piece of paper, no change. Moreover I noticed the hiss is coming only from the tweeters of the monitors. When I unplug the audio cable, the hiss is almost gone so I assume the source of that noise is the digital piano itself.

The worse problem, the "resonance" or "booming" of particular keys is the main problem though. I have recorded a short sample in which the left hand includes one of the worst keys - C1 and C2. Its recorded using the built-in mike of a notebook but still I am sure you can hear the two parts when I use the aforementioned keys. Is it the piano samples in the Yamaha so I have to live with it or is there anything that I could do? They all sound okay in headphones though.

Don't mind the cracks and pops (probably the pedal) and my funny playing skills
Here is the short sample (can be played online without downloading): http://www46.zippyshare.com/v/66694034/file.html

The fact that the resonance is from 2 of the same notes (C2 and C1) implies that the room is resonating - it may be that two hard, opposite surfaces near the piano are a multiple of one wavelength apart. The wavelength for C1 is 10.4 M and for C2 is 5.2 M. Might you have two walls or floor / ceiling that are 5.2 meters apart?

Wow, that never struck my mind, what an idea, thanks! I will measure the room. I think the height IS 2,6m which x2 IS 5,2m. Is that possible? If so, I guess there is no defense against
that, is there? Apart from moving in another flat?

EDIT: May I ask where you found the wavelengths? I google up this (http://www.phy.mtu.edu/~suits/notefreqs.html) and the lengths are different there.

I just googled "middle c wavelength" until I found a site that showed all of the notes on a piano: http://www.liutaiomottola.com/formulae/freqtab.htm. If it's the floor / ceiling combination, a rug near and/or under the piano might help. This is obviously not a unique problem!