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Hello,

I discovered something strange today and I hope someone here had noticed this before if it is indeed a problem with CLP-280.

So far we have been playing our CLP-280 on either 40-75% of the volume or via headphones and so we didn't notice the problem. But today we had guests one of whom is a professional piano player so she played at full volume to show the full beauty of the sound and we all noticed that A above middle C (and ONLY this note!) makes a strange noise coming out of the rear speakers. This only happens with iAFC turned on and only with voices Grandpiano 1 and 2 (but NOT with guitar, harpsichord, organ etc etc). Switching iAFC off or turning the volume down or playing more softly or listening via headphones makes the problem go away.

If I put my head behind the piano I clearly hear the source of the noise somewhere inside, near (or above?) the part where the rear speakers are. I shielded the metal fireplace with some soft cloth (it is directly behind the piano) but it didn't make any difference.

The distance from piano to the wall (not counting the depth of the fireplace) is about 40cm which should be more than adequate. The iAFC has been calibrated properly, of course.

So, has anyone noticed this?

I will phone Yamaha support tomorrow morning, but maybe someone knows about this problem and has some advice?

It can't be a problem with the keyboard action because it is voice-specific and iAFC-specific. I think one (or both) of the rear speakers may be a bit loose and so are vibrating? Any other ideas?

It sounds like a vibration, but could be that the iAFC portion of the audio system didn't like being overdriven, and that A just happened to be the resonant frequency. It make sense that the piano voice would be the culprit, as its harmonically dense, particularly at high strike velocities. Most audio systems--DPs included--don't respond well to being played at maximum output. Amplifiers start clipping, the sound is degraded, things start vibrating, and speakers can be damaged.

75% is a good max.

Alden

I would try recalibrating the iAFC. If you haven't set it to the room/location you have placed it might not be behave the way you anticipate. iAFC does not work through the headphones.

Dean, of course iAFC has been calibrated. And I also tried resetting the instrument by booting with rightmost C pressed down. Didn't make any difference.

The opinion of torakusu does make sense but still that is not very encouraging --- I expect all the notes to play properly even at maximum (or near maximum) volume...

Actually, what torakusu mentioned about "amplifiers clipping" is very interesting...
I remember recording CLP-280 sound via AUX-OUT with output level set to Fixed on CLP-280 side and forgetting to set the appropriate level on the PC soundcard side. Well, what I saw in the signal looked exactly like the top bits of the amplitude being "clipped off". Why do I mention this? Because the sound of this A on CLP-280 seemed very similar to what I heard with such improper recording (i.e. until I properly regulated the level on the PC side to make sure no such clipping occurs anywhere).

I'd bet that's what you heard; a clipped waveform.
If everything in the iAFC audio chain is running right on the ragged edge and there was a small hump in the frequency curve at 440Hz, that's where it goes over the edge--the waveform clips and distorts.

If you turn the knobs all the way up at Royal Albert Hall and yell into the mic, guess what you'll get (other than hauled away)? No system is immune to being overdriven.

Cheers,
Alden

Tigran, this is very interesting indeed..(and disturbing) I've had my clp280 for some 3 months now and never noticed anything like this before.I usually play with 60-70% volume(louder with headphones), with grandpiano1 sound edited followingly(all other settings at default values) :
1.Touch Response ...Light
2.StringResDepth ...6
3.DynDamperFX Depth...80(after iafc calibration)

So 1st thing after reading your post I tried to replicate your problem on my clp, and sure thing, the A above middle C resonates in a weird metallic manner when played with full volume and struck with a mf to f attack,this happened with my own soundsettings and also with the factory settings after pressing the rightmost C and turning the power on.

Then I tried lowering the volume to 75% and the metallic aftersound is still there.Now imagine my wonder as I proceed to turn sound level down to a measly 40%,strike the key with a f attack, and still hear that strange sound if I listen carefully !

I then turn iafc off, but with my clp, lo an behold,
I hear the strange metallic sound just aswell as with iafc on !

So this is clearly not an iafc-related problem..Neither has it got to do with overdriving the speakers with excess volume(since I also clearly hear that sound on lower volumes..btw my girlfriend can hear it aswell, so I'm sure it's not in my head only or anything like that..)

So next I proceed trying the A over middle C on different sounds(75%volume) and I can ALSO hear it on the following :

a. mellow piano(same sound is there, it is just shorter and harder to hear)
b. rock piano(almost any key on the piano makes this same sound, no joke!)
c. harpsichord (it's there, but very short and almost perfectly disguised,try a mp-mf attack)
d. honky tonk piano (easily audible)
e. grandpiano2
f. bright piano

I tried all of those with iafc both on and off , and the metallic sound was audible on all occasions.

Now this metallic aftersound is clearly not meant to be there, it is NOT part of the slightly metallic touch of the sound charachteristic to yamahas acoustic grands, for instance in the lower octaves if you take any octave with a f attack and use damper pedal you will hear the good metallic sound that a yamaha should produce.This is also audible and well done on the clp280...
But the A above middle C making this sound is not natural at all..

And on top of all that I found out something else too : the G after middle C is coming out louder from the speakers than the A or other adjacent keys, if depressed with the same speed and strenght..

So now I'm thinking there is only one feasible explanation to all this phenomena, and that is :
The sample itself is bad..
It sounds a bit depressing that a 3000e piano should suffer from only 1 or 2 bad samples..I mean if they got 86 keys to sound good, then why let these 2 defective ones stick in there ? well who knows? ...what I do know is that sampling a grandpiano to perfection can be very hard even with modern gear.. so maybe this is a plausible answer to this riddle...

Yikes

Full volume!!...I have a CLP170 and just couldn't play it at full volume (the missus would go bananas for one - let alone the folks next door!)


Full volume would be so overblown in my room you must have a big room?


Lee

Hi Baco80,

I'll let you know what happens. I spoke to the technician (the local one attached to the shop, they asked me to NOT contact Yamaha as they will "sort it out" themselves). This gentleman listened to my description of the problem and said he will order all the circuit boards related to this model and come and see what the problem is later on this week. He didn't want to come before the boards arrive because he seemed to think the fix will definitely require a board replacement.

So, I may be wrong but it seemed they actually knew of this problem and if the fix is to replace one of the boards containing the sound samples then you may well be quite right --- i.e. the sound sample itself may be bad.

But, Baco80, are you absolutely SURE that the problem with iAFC off is of exactly the same magnitude as with iAFC on? Because with iAFC off I don't hear any problem but my ears are not perfect (Some people play by ear, I play by heart )
If so, then what I have is another problem, not the same as yours. I.e. in my case with iAFC on I clearly hear the problem in the rear speakers so it is either the rear speaker vibrating or the iAFC is overdriven and amplifier clipping occurs as torakusu suggested.

Anyway, these are just my guesses. When the chap comes to see my CLP-280 and fixes it I'll let you guys know what the problem was.

Sounds fine here even at max volume. I do have vibrations when I use some weird cheap sound from the XG midi, but not the main sounds.

My only complain with the speakers is the threshold where the bass speaker(s) that seems to be centered around the low D. But I never tried to adjust it.

Tigran, now I'm not so sure anymore that we are experiencing the exact same problem.Because I do hear the same weird metallic after-ringing noise in A above middle C with iafc off.It is only slightly quieter with iafc off.And, just discovered, I can also hear it with headphones
Tigran, how would you describe the weird sound you hear? Is it at all like a metallic ringing aftersound that reminds a bit of a single distorted harp sound?

oh and what about the G after middle C?
Does it come out louder on your clp?

Then on the other hand I have to state that my ears are especially sensitive to all kinds of electronic sounds as I've been listening to and doing electronic music on my computer for more than a decade, so maybe I'm simply overly sensitive?
And I'm not really goin to loose sleep over these minor problems because they are only audible when I play a single note as a test.when I play music I usually don't have time to hear or acknowledge some minor defects in a few single samples like is the case here. It's a bit funny to me that most DP aficionados cry wolf as soon as they hear some slight, minuscule, harmonic dissonance(or aftersound or vibration) in the DP's sound..
Incidentally, when these same unwelcome(I'm am not talking about the complex natural harmonics that all acoustics make)ringings/aftersounds/vibrations
are happening on an acoustic, everybody is just saying : hey , it's a huge acoustic instrument, some "fault" or anomality in the sound is actually expected ! so all I'm saying is , if you only hear this weird sound while playing a single key as test on very high volume, if you can't hear it while playing normally, why care?

Baco80, it looks like a completely different problem. Mine is very obvious, not subtle at all. I am very surprized I didn't notice it before. It is like some loose screw vibrating or (oddly the sound is similar) the amplifier clipping.

In my case it definitely does NOT happen with iAFC off and neither does it happen with mellow piano, rock piano etc etc (all the ones you mentioned) but ONLY happens with grandpiano1 and grandpiano2.

I can hear it even with 60% volume or even at 50% volume if the key is striken at maximum velocity.

So, I agree with you that from what you describe the problem you are seeing is no big deal at all (and I probably have it too but didn't even notice

But the problem I am having is not acceptable as one can clearly hear it even when playing a melody or even just playing back a MIDI file (if the song has those A notes) at 75% volume. Neither you nor Xill have it so it is specific to my CLP-280 and I expect it to be fixed. If it is not fixed I'll expect a refund (or an upgrade to CVP-407

Btw, I just tried and the G above middle C does not come out louder on my CLP-280. Of course i tried with Fixed setting to make my irregularity irrelevant. Or if it was louder it was not sufficiently so to become noticeable.

I just discovered something interesting.
That noise from the rear is coming out ONLY FROM THE LEFT SPEAKER! Definitely nothing on the right side. So, something may be loose on the left side rear speaker. Actually, it even appears to come out slightly above the speaker and towards the corner, i.e. the top left (or looking from behind the top right) corner. If I put my hand there I think I can feel the vibrations connected to this noise (but here I may be mistaken).

This is the same sort of thing that makes acoustic piano techs crazy. One note produces an odd noise, and after crawling all over the piano you find out its a loose screw on a lid hinge.

BTW, there are no service alerts on the 280. I'll be interested to hear which boards the tech replaces.

Alden

Can you describe the sound?

THe way iAFC works is: there are two microphones on the top front of the instrument that pick up the room noise, and send it back through the signal processor and to the rear speakers.

This is the only time the rear speakers make any sound at all. If one of the speakers isn't creating any sound whatsoever, it could be that it's disconnected internally, or one of the internal mics are disconnected.

Out of the box, these need to be assmebled, including all the internal speaker cabling, so maybe something wasn't setup correctly.

I am certain that the tech will figure it out at your place, but it could be that the sound is normal, hence my question to the sound description.

Jeff, maybe I should try and record A with iAFC off (i.e. normal) and with iAFC on (i.e. problematic). But I only have a simple dynamic microphone so I doubt whether I will succeed, but I'll give it a try anyway.

The CLP-280 was assembled by the person from the shop as delivery included assembly and removal of packaging. Although I was standing there I didn't check the minor details like the attachment of cables etc. I see from the manual that there are plenty of opportunities here to make something vibrate if not attached properly --- Ah... I wish I had assembled it myself! Anyway, only a few more days' patience and we should know what it is. The tech promised to come early this (coming) week.

Some more info: I detuned A away from 440.0 to make it 466.8Hz and then the problem shifted down to Aflat.

So, it is not an electronic problem but a mechanical resonanse of A440 with something inside the piano which starts vibrating. This something is near the left rear speaker but as there is a back panel I can't get to it to see what it is. Unscrewing the three screws on the back makes no difference as presumably this panel is held by something else as well (which would require lifting the whole top thing out of its place to open, but it is too heavy, so I'll wait for the tech to come this week).

It seems possible (even likely) that the person who assembled it made some mistake and left some cable inside dangling which causes this vibration.

Update: I am still waiting for the tech to come and have a look at my CLP-280 (it has been more than 2 weeks since I reported the fault).

In the meantime I have recorded the A4 key with and without iAFC and put the WAV file here:

<A HREF="http://www.bibles.org.uk/mp3">A4 problem on CLP-280</A>

I used Fixed velocity (70) so all sounds are identical in loudness.

I only have a cheap dynamic microphone so it doesn't show the problem as clear as a human ear listening to it does. But still even from this bad recording you can hear something vibrating (in reality, i.e. "perceived reality" this vibration is much louder than what this microphone is capable of reproducing)

Update: Yesterday the expert came and fixed my Yamaha CLP-280. As I suspected the problem was due to resonanses (more than one) so it was an utter waste of time to wait for almost a month for the parts from Yamaha. Nevertheless, I am very happy and grateful to the person (Robert Woodward of clavinovarepairslondon.com) who fixed it and remain a happy customer of Chappell of Bond Street.

The resonanses were caused by various loose screws inside the cabinet --- the biggest one being due to the left rear speaker (as I suspected) and a minor one due to some board also screwed in not tight enough.

Now everything is perfect (not just A4/440 and I am even more convinced than ever that CLP-280 is the best DP in the world!

Good to hear it's all better.
Were the loose screws due to the assembly at the factory or from whoever assembled it at the dealer?