HIGH FREQUENCY MODULATION IN CD PLAYERS

[coca]

I have a couple of friends that claim they can hear high frequency modulations in  some CD players that is so bad that because of the pain it creates in their ears , they very often have to leave the  room in a hurry. This happened this weekend when a group of us was auditioning a new CD player. Has anyone heard of this phenomenon? What would likely be the cause of this high frequency noise in the CD player? I have normal hearing, so I coud not relate to their experience. However, the player otherwise sounded great.

Bernie.

[Natural Sound]

What were the components downstream? Did you try a different CD player with the same downstream components? Different CD's etc.? I guess what I'm trying to say is that there are a lot of variables. Maybe a little more information will help the group answer your question.

That said, I have experienced this phenomenon in solid state equipment. Not so much with tubes though. Also, some older discs that were mastered in analog but poorly transfered to digital might present this effect.

[Paul Joppa]

Dangerous territory! The obvious technical explanation is aliasing, but it is widely observed that non-oversampling DACs with low-order filters (which would create the greatest amount of aliasing) sound the best. Since each of these observations disproves the other, people have strong feelings that are not resolvable. I think the only hope is to come up with a better theory. It hasn't happened yet...

[coca]

Natural Sound, the CD player used on the weekend was one having tubes in the DAC. The preamp and the power amp were tube units as well. However, it dosen't seem to matter whether the units have tubes or not. The cost of the units dosen't seem to matter either. It  just depends on the CD player. Although, I have heard one of the guy's complain about the same high frequency noise in analogue componets from time to time, but a lot more often in certain CD players.
There is also one other thing that one on them complained about, and I am almost embarassed to comment. However, here goes. He claimed that when he was younger, he had the curse of being able to  hear bats in the high frequency range, and it was a painful experience. Of course, I still laugh about that claim.
I also wondered if the sampling rate had anything to do with it. This CD player otherwise is a very good sounding unit. My CD player has tubes in the DAC as well, but he has no complaint about it, although, it's a different Brand. I will be shortly installing an upsampler in mine, and it will be interesting to hear about it's effect on him.

Bernie.

[Jim R.]

Bernie,

I've experienced this from time to time and it always seemed to be a room acoustics issue more than anything.

Next time maybe try putting something sonically absorbent at the first reflection point relative to where this guy is sitting.

Worth a try anyway.

-- Jim

[coca]

I will mention that to him. I know that his room acoutics are far from ideal. In fact, they are almost as useless as a pocket in the back of a "T" shirt. We will have another go at it.

Bernie.

[4krow]

Man, I thought I was the only one. At 54, you would think that would be a thing of the past for me, but from time to time, I hear hi-freq from unknown sources, and yes, sometimes(rarely) from digital sources. Strange as it might sound, one of my ears can hear a dog training whistle if it is close enough, and the other one cannot. I notice that very high frequencies are touchy as far as head position is concerned. A little off the subject, I have heard items in a room vibrate ever so mildly, yet still drive me crazy till I find the source.

[Grainger49]

Greg, get thee to the Wal-Mart office supplies.  Buy some of the mounting putty like Blue-Tak.  It is great for killing vibrations and 1/10 the price of real Blue-Tak.

[Jim R.]

Hi Greg,

You wrote:

"I notice that very high frequencies are touchy as far as head position is concerned."

Which is the same thing I've heard and found the same things as you -- that it goes away when you move your head from the place where you're getting this effect.  Which is why I believe it is an acoustics issue -- a high frequency nodal point if you will.  It can sound like a "pain field" and is super annoying to me -- at basically your same age, to the point where if it happens too much I have to leave the room or make some other change to the music, system, my position or whatever.

It's amazing how many rooms at shows like RMAF I get this in too, and it seems that either others aren't hearing it r they arenn't saying anything about it.

Anyway, since taking the time to do some acoustic treatments in my listening room, I cannot make it happen any more, regardless of source, music, volume or sitting position.

-- Jim

[coca]

Greg, Jim, this sounds encouraging. We will have another go at it.

Bernie.

[4krow]

hmm, room treatment eh? Now I should have thought of that. I was just gonna wait till I got a little older, heh heh. Related to age, I have a new hearing problem,,,tinnitus. I think it is definitely related to my high blood pressure, and I am taking steps to deal with it. I have had this before, but at a very low frequency. Now it is at a very high frequency. maybe I need 'room treatment for my ears'  heh heh

[Grainger49]

   .  .  .   Related to age, I have a new hearing problem... tinnitus. I think it is definitely related to my high blood pressure, and I am taking steps to deal with it.  .  .  .   

I have had this for years.  I went to an audiologist who suggested taking Folic Acid.  It has cured the right ear and attenuated it in my left.  Cheap and worth trying a bottle.  Take two a day to start with.  If the bottle doesn't help you haven't lost much.