@intika Just to complete, I would like to add that Electromagnetic fields' values without frequency or frequency range specified are quite meaningless IMO. The 3V/m Belgium commercial limit is excluding TV and radio FM broadcasters, worth to mention. The regulators' upper frequency range is...

Tolerances are around: - Electrical Fields < 10V/m - Magnetic Fields < 1microTesla. Keeping devices at reasonable distance, >30 cm for example, significantly reduces EMF. In laptop case, it seems that the main EMF contributor is the power supply PS (1.5kV/m). Therefore don't use the PS for...

Well return your Blue Jeans fibers. Why did you purchase/try them?

Clear, thanks. i was asking because: touching with metal/fingers/plastic has no incidence at all in the optical unless Blue Jean optical has its metallic connector touching your Denon screw or some metallic case..... passive optical switches are adding additional attenuation to the optical...

Hi @Sebastian.Athea , You are perfectly right, watching your video I got the wrong idea that you were dealing with an SPDIF cable instead of a fiber (Toslink). My misunderstanding, sorry. Then return your Blue Jean optical fiber. Is the picture dealing with your DAC? Can you tell us more about...

Are you sure your generic cables do also have metallic parts/covers at the extremities and not plastic ones? Your DAC is most probably not earth/grounded via AC plug. Same should apply to your SPDIF switch. Therefore by touching it your body is interfering (resistive ,capacitive path to...

Mine has been during 3 years 95% of time permanently plugged. Batteries were also still in the 4-5 hours working range. But at the end the white light and humming/buzzing were quite long to stop in most of cases. For safety reasons I removed the inflated cells. Mojo is now still working in...

Time to change your recordings methods then :). Use ultrasonic mics at eye & skull level rather than record them at ears (binaural).

More details in this not so recent thread: https://www.head-fi.org/threads/ripping-cds-that-have-pre-emphasis.423506/ Some updates are probably needed regarding ripping software but still instructive.

I regret that you have not or can not share any DAC measurements showing the benefits.

For your purpose I am afraid you will need much more ultrasonic power than the one available in music recording.Not even talking about having the mics characteristics and exact positioning during the event.... If not already done you may check power involved in ultrasonic applications and their...

Even at small Jazz club my ears are rarely less than 5 meters from cymbals and almost never in free line of sight (no obstacles). A few posts back I did provide @KeithEmo with closed mic ed cymbals hits. At that time I was requesting how he could retrieve room characteristics from its ultrasonic...

Not exactly 20log(2/0.5) + AIr Absorption at 200 Hz ( neglectable) -> roughly 12dB vs 14dB. ( 200 Hz has a 1.5 meter wavelength, in principle the 1/r attenuation is not applicable interactions between waves are more complex. I did the above calculation just for copping with your example )

Ultrasonics do follow same law as any other frequency provided that they are in Far Field (greater than two wavelength distance). Atmospheric Absorption is frequency dependent. ISO 9613 calculator provided is dealing only with such absorption. https://www.mne.psu.edu/lamancusa/me458/10_osp.pdf

2 meters: ~14 dB attenuation for f=30 kHz @2m/0.5m with 50% humidity in free space.

No Keith. You have distance! - 20 log r in Free space or Fresnel zone. It is the case for f=30 kHz at 6 feet.

The 50 dB attenuation for f=30 kHz @20m/0.5m with 50% humidity in free space is indeed very correct. :)

Do you mind sharing the DAC Output effects of an item not coping with your standards? Just the output, no item name or any EMC levels. Thanks.

@KeithEmo I will let @gregorio reply more in details if he feels like. But what you totally miss in your point 1 and previous posts is that sound pressure attenuation in outdoor does not depend solely on the atmospheric absorption coefficient! @gregorio provided the correct estimation in...

Curious USB cables https://curiouscables.com/ may be a good choice to start with.

Let us take DAC case. It is not difficult to measure its susceptibility to DC/AC/ground noises. It is not difficult to measure its susceptibility to EMI/RFI with cables connected or not. In principle those effects should be insignificant when translated into output audio levels. Now in case it...

Excepting few of us we are all surrounded by thousands of devices generating EMF. The number of such devices will increase exponentially in the coming years. Manufacturers do play with people fears even if all this accounts for 0.0001 dB in the main cases.

It is not hard at all to measure. People involved in cable business are for obvious reasons not prone to publish such measurements.

What a waste, in my opinion, for you not to share or better put into application what you have learnt from experts. As a member of the trade, @KeithEmo has potentially more reasons not to do it fully compare to you. By the way, I am taking the opportunity to thank @gregorio for his relentless...

IMHO, I would say that for example ferrites on top of BNC are acting more as a workaround when dealing with item noises from FPGAs or CPUs not properly managed in the device environment. I should even add that the workaround may be provisory since magnetic properties of ferrites are changing in...