# Phoenix P5 sound noise



## [email protected] (Jun 16, 2008)

Is anybody else annoyed by the high pitched 11K noise coming out of the Phoenix P5 sound cards?


----------



## nkelsey (Jan 4, 2008)

What sound file are you using?


----------



## [email protected] (Jun 16, 2008)

All sound files. Its not in a sound file it has to do with the switching frequency they use.


----------



## Gary Armitstead (Jan 2, 2008)

Check the Phoenix website for a later version of the program. There is a download available for upgrade to V8.5, v1.2.90, dated 30 October 2009. Might solve your problem.


----------



## [email protected] (Jun 16, 2008)

Thank you but thats for the computer interface and I am currently using it. I have 9 P5s and they all have that noise. It is most pronounced on my Dash9 with the speaker pointing up.


----------



## Jim Agnew (Jan 2, 2008)

It's the new air pop sound that was added. You can turn it off, if you have the program.


----------



## [email protected] (Jun 16, 2008)

Thank you but its not an air pop. The sound file does not matter, steam or diesel. Phoenix uses a 22k switching frequency (this is per Phoenix when I called them) and the leftover 11K is coming out the speaker when ever the engine is started up and running. The noise is full time and only goes away when you stop the motor, then the output is muted and it goes away.


----------



## TonyWalsham (Jan 2, 2008)

Don. 
I am perplexed. 
I have sold and fitted more than a dozen of Phoenix P5 + P5T combinations. 
I have yet to hear any extraneous noises when used with battery R/C. 

What type of installation are they?


----------



## [email protected] (Jun 16, 2008)

I am running DCC but have ran the P5s on DC too. The installation should not matter other than a speaker that will reproduce that frequency range. When out door running, its not as bad but running inside it get very annoying after about 15 mins. and when you have 5-7 engines sitting idling at the same time its bad. I take it that no body else is bothered by it. Maybe my hearing is too good.


----------



## TonyWalsham (Jan 2, 2008)

It is a bit difficult to be bothered by something you cannot hear. 

Although humans can hear sounds as high as 11 KHz, it is not usual. So, yes, you may have superior hearing.


----------



## Torby (Jan 2, 2008)

Never noticed it. Maybe I mistake it for my tinnitius?


----------



## Greg Elmassian (Jan 3, 2008)

Humans, when young can hear sounds up to 20k not 11k... almost everyone can hear 11k in mid life, less as they get older... I can still hear 20k in one ear and 18k in the other. 

(this is one of the reasons stereo speakers are usually spec'd at 20 to 20kHz) 

Regards, Greg


----------



## Torby (Jan 2, 2008)

I thought of this last night, "Ask a kid. They can hear things we can't."


----------



## Cougar Rock Rail (Jan 2, 2008)

Interesting....any chance you could post a video so we could maybe hear what you mean Don? I've never heard it from mine, but then I've lost a lot of upper and low end hearing from running heavy equipment.... 

Keith


----------



## jimtyp (Jan 2, 2008)

I've never heard any noise either. Have several P5s with DCC. Could it be your speakers are causing some kind of feedback?


----------



## [email protected] (Jun 16, 2008)

I set up a P5 and speaker on my bench at work and had coworkers listen. I first played an 11K audio signal from an audio generator so they would know what they were listening for. Of the 7 people that listened. 3 could not hear that high and couldn’t hear either of the signals. 4 could hear both the audio generator and the 11K coming from the P5, and of those 4 people, 2 said “shut that damn thing off” those same 2 people hate the 15K sound that comes from TVs.


----------



## Greg Elmassian (Jan 3, 2008)

Yep, many people can hear the 15734 Hz horizontal oscillator frequency in a CRT TV. 

Regards, Greg


----------



## George Schreyer (Jan 16, 2009)

I still hear TV's and it drives me nuts. Tone is higher in frequency than my tinnitus. I haven't heard my P5 though.


----------



## George Schreyer (Jan 16, 2009)

I just put the Doodlebug with the P5 on rollers and ran it, don't hear 11 kHz. 

I put a speaker on an audio generator, I hear 11 kHz 

I put a speaker LIKE the one in the Doodlebug on the audio generator, don't hear it. 

My speaker isn't passing 11 kHz.


----------



## George Schreyer (Jan 16, 2009)

Don, have you considered putting a low pass filter on your P5's?


----------



## rmcintir (Apr 24, 2009)

George, best answer yet. 

Here is something to play with: http://www.st-andrews.ac.uk/~www_pa/Scots_Guide/experiment/lowpass/lpf.html


----------



## TonyWalsham (Jan 2, 2008)

What DCC decoders is Don using? 
It could be the PWM frequency. That disappears when the motors stop.


----------



## [email protected] (Jun 16, 2008)

As far as decoders, I'm using NCE, Lenz and Digitrax mostly and sense I can power up a P5 on the bench with a speaker and no decoder. I don't think that the decoder is a factor.
As far as a low pass filter, To cut out the level of the 11K signal I will need somewhere in the nieghborhood of -30 to -40db. And a low pass filter -24db/octave would be a lot of big parts and take out a lot of the good audio I want to hear. So I am currently working on a filter system to keep the good audio and get rid of the bad. Have a prototype made and am tring it tonight.


----------



## Greg Elmassian (Jan 3, 2008)

Yep, an 11k notch filter would be good... any idea how "wide" it needs to be? 

I don't dispute that others have not heard this sound, I think maybe people did not take to heart Don is listening inside. When stuff is outside, you don't always hear all the detail (and maybe are not listening for it). 

Regards, Greg


----------



## Gary Armitstead (Jan 2, 2008)

I only have two engines (steamers) equipped with P5 cards and I don't hear this sound inside. But then I have tinnitus! 

I have no idea where you live. But if you are in California, give Jonathan a call at EMW. I'm sure he can give you an answer.


----------



## Torby (Jan 2, 2008)

Been a long time since I've heard a tv.

Maybe a ferrite bead around each of the wires powering the phoenix? But then, I thing ferrite beads filter higher frequencys. Let me google... Hmm, Don't think that'd help. Maybe one of those inductive filter boards?


----------



## [email protected] (Jun 16, 2008)

Problem solved, I built an 11K filter that is -3db by 8.5K and -43db at 11K. That takes the 11K noise below audible levels and leaves all most all of the good audio. On the bench switching the filter in and out I can’t hear any loss of the engine sound but the 11K noise is gone. Now for the first time I can say, with the adjustment flexibility and sound quality of the Phoenix sound “that is one nice sound card” or as Tony The Tiger would say “Ther-r-r-r-re Great” (Well, with the 11K noise gone anyway)

A bigger question I have though is; The P5 has been out for over 3 years. I have been using them and annoyed with the noise indoors and out for 7-9 months. Nobody else has heard this?

Say you as a large Scale operator have just had visitors over. Visitors that can hear 11K just fine. Your visitors leave and you think that things went well. But as your visitors are leaving they are thinking ”WOW, that was terrible, that high pitch noise”. . . . . . .


----------



## Dan Pierce (Jan 2, 2008)

Would you please post the circuit used for eliminating te 11khz noise. Others want to try it.


----------



## Torby (Jan 2, 2008)

I seem to remember something about you could make a very narrow notch filter with phase locked loop. If I weren't so lazy, I'd google it.

Glad you found a solution!


----------



## Del Tapparo (Jan 4, 2008)

Has anyone bothered to contact Phoenix Sound (the manufacturer) about this problem? That would be the place to start.


----------



## Gary Armitstead (Jan 2, 2008)

That's too easy Del.


----------



## [email protected] (Jun 16, 2008)

OK, I couldn't figure out how to get a photo to show up on this forum so the address below should get you to the info


http://www.gringodon.com/phoenix.html


----------



## [email protected] (Jun 16, 2008)

A suggestion from Del was to call Phoenix. Did anybody?

Just put it on Gary. I will post any info I get.


----------



## Gary Armitstead (Jan 2, 2008)

Don, 

Did you get an answer yet?


----------

