DIGITAL NOISE

[♔Chello]

DIGITAL NOISE

For a long time I thought I was the only one bothered by this.

I first noticed the problem when USB was launched - everything based on this had an intolerable noise that was especially annoying around 15kHz to 25kHz.

Many claim that bad USB cables are the cause, but I have replaced all of them with expensive versions - without ANY change.

However, there are several factors that come into play, such as the individual's ability to perceive such high frequencies - most people over 37 have severely reduced hearing above 10kHz, while I am "blessed" (or cursed..?) with being able to hear frequencies up to 25kHz or higher.

Secondly, very few people have speakers that are capable of reproducing such high frequencies, while I have had them for many years.

A good DAC/AAC that handles 24 bit (or more) is also necessary.

Thirdly, there are not many recordings that have such high frequencies, and all Mp3 is excluded, while Wave and FLAC can have them, and DSD/SACD is the best, with 24 bit - or higher.
It is important to know that Wave and FLAC are often only 16 bit (CD "quality"), which gives a greatly reduced resolution compared to 24 bit.

A lot of recordings that are available as SACD/Wave/FLAC are actually 16 bit Wave that has been "converted" to 24 bit SACD/Wave/FLAC, which means that they are only 16 bit - it is practically impossible to increase the bitrate by conversion - well-trained ears hear this immediately.

Back to the point:
Digital noise.
I have experienced digital noise for years, even with quality products such as the AUNE S6 DAC and MOTU M4 AAC, which both support 32 bit.
Both of these have the best chips on the market installed.

Another source of problem is the amplifiers used; are these analog or digital ?
Analog amplifiers such as tube are the worst of all, as they act as an antenna to digital noise - mobile phones and the like emit an extreme amount of digital noise.

Ordinary analog ones that are particularly well shielded can work quite well, while digital ones that are very well shielded are the only ones that work well enough.

Digital amplifiers with poor shielding are a nightmare.

So how to solve the problem ?

The most effective thing is to place the PC as far away from the program sources as possible, while I pretty much have to have the PC placed close, which maximizes the problem.

So other solutions have to be tried, and the only effective one is USB Isolation.

Some time ago I acquired one of these, and this works quite well with the AUNE DAC, but has no effect on the MOTU AAC, probably because this gets power via USB C.


I have recently acquired a new sound card, which is also USB C based, and have also ordered special USB Isolators for both USB B and C, which can be connected to each device.

Hopefully these will reduce the noise to a tolerable level.

I have planned a test of this new sound card, but will have to wait until I receive the USB Isolators.
I will get back to the subject as soon as possible.