HDMI audio cliks and pops and cracks

I have the this problem with my HP dv4-1125nr. The audio out of the HDMI port to a HDTV or a monitor with integrated speaker has a lot of pops and cliks and cracks and all sorts of noise.
If the processor is not heavily loaded the sound is better but if you move windows around or play a process intensive clip the audio is very noisy.
I posted this on cnet reviews

If you are thinking of connecting an external monitor to this device or use it with your HDTV you will run into performance issues. The video quality is not great, the video setting optimisation is limited but worse of all the audio quality out of the HDMI link is really bad.
When playing a video clip either personal or downloaded from the internet the sound out of the HDMI connection has lots of pops and clicks. Even when the screen saver is running, the audio output is let's say very annoying.
If you were hoping to use this laptop to watch movies the experience will be very bad when using an external digital monitor.
I called HP multiple times and they had no idea on how to fix it. The basic suggestions (change the cable or try a different monitor) do not work. They suggested bringing the laptop back to Best-Buy. Well I tried a new laptop there with the Geek-squad and all the laptops (HP dv4-1125nr) had the same issue. Worse of all, Best Buy cannot even process a return on this machine as HP does not autorize a repair (not sure what that means) but basically I am stuck with a laptop with a bad HDMI audio.
I hope HP is looking into this issue. When playing regular DVDs the "noise" is not so pronounced but still bad for a good movie experience, when playing highly compressed files (MP4, etc) the sound is really bad.

 

What you hear...


Understanding pops and clicks

Pops and clicks are a direct consequence of undesirable currents flowing through a loudspeaker. The main property of these undesirable currents is that they have a discontinuity - or sharp change in current - with respect to time. Understanding why a discontinuity causes a pop or click requires a brief examination of the electromechanical structure of a loudspeaker.


The most common type of loudspeaker consists of a fixed permanent magnet and an electromagnet attached to a diaphragm that is free to move in a supporting structure. The electromagnet moves when a current flows through it, forcing the attached diaphragm to move, resulting in sound. In an ideal loudspeaker, the displacement of the diaphragm is proportional to the current flowing through it.


It is worth noting that a time varying current results in a moving diaphragm, while a constant current results in a diaphragm that is displaced, but not moving. A discontinuity in the current causes a sharp, sudden movement of the diaphragm, giving rise to a pop or click. Generally, clicks are low amplitude events with high frequency content, while pops are higher amplitude events with a wider frequency spectrum. Preventing pops and clicks from appearing in the audio subsystem essentially boils down to ensuring that no discontinuity arises in the current flowing through the loudspeaker.



Long story short, your hardware and software is not hi-fi enough to detect and mute these errors on HDMI. That is why you hear them. High compression = loss of quality, therefore mp3s, mp4s, etc will pop louder than DVDs

 

whishmaker,

I appreciate your description of the cause of pops and clicks.
In fact I am an electrical engineer (a rare analog one) and I agree with you.
Even though the clicks and pops are discontinuities, the speaker simply reproduces with the highest fidelity the audio that its been presented with.
The audio output on the analog (line/headphone) is well behaved stereo.
While the digital audio sent through the HDMI intoduces the noise. It could be the clock receiver or the audio decoder that does not properly strip out the stream but I have the feeling that the issue is on the transmitter side where the SPDIF clock may not be in sink with the video clock or the timing is a bit off. Unfortunately this laptop does not have a strait SPDIF output that I can process without going through the HDMI cable I believe.
Both my 22" HP monitor and my 42" Panasonic Plasma (Hi-Fi enough) reproduce the same sounds, therefore the issue is with the laptop/ Trasmitter side not the speakers.

 

Hats off to ye mate. I always wanted to be one of those but it wasn't meant to be. Sound is my hobby . I might have been unclear. When I mentioned that your devices are not HI-Fi enough I was reffering to your laptop. I apologise for any confusion. Most laptops on the market with HDMI are a marketing gimmick to attract customers. Back to the issue at hand...


Ensuring a noise free audio subsystem clearly requires attention to detail. Hardware requires a focus at a low-level while software requires attention at a higher-level. Your lappy is simply not capable of doing this. You can change 20 million cables but super gold plated ones, etc .


Similarly with HDTVs...

As the trend in HDTV continues towards slimmer body profiles and more energy efficient devices, HDTV manufacturers are migrating to Class-D audio amplifiers because of the space saving and efficiency they offer. This has resulted in the increased use of PWM (pulse-width modulation) outputs in audio subsystems.

 

Question for the OP. Is the audio coming out of your HDMI stereo or something like Dolby Digital 5.1 Surround?

 

I think HP is right I'd check the cable, most are cheaply made in China. I'd bet if you tested the pins with a voltmeter many would be dead, I know they don't all have to be alive but one would have to think the more that are alive the more there's the chance of getting the reproduction you seek . Unless you shell out for the Mickey mouse cable it's never going to happen and if you are using the Mickey mouse cable like our hobbyist said this technology has it's limitation.

I bought a gold plated cable with most of the pins being DOA when I contacted the dealer to state this, he just did a refund and didn't even want the cable back, if I sold you something I knew was good I'd want it back before I refunded, to make sure you weren't trying to put one over me!