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shooter's picture
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Test your hi-res systems performance.

If you're curious about the performance of your own system, the following samples contain a 30kHz and a 33kHz tone in a 24/96 WAV file, a longer version in a FLAC, some tri-tone warbles, and a normal song clip shifted up by 24kHz so that it's entirely in the ultrasonic range from 24kHz to 46kHz:

 

Intermod Tests:

30kHz tone + 33kHz tone (24 bit / 96kHz)  [5 second WAV]  [30 second FLAC]26kHz - 48kHz warbling tones (24 bit / 96kHz)  [10 second WAV]26kHz - 96kHz warbling tones (24 bit / 192kHz)  [10 second WAV]Song clip shifted up by 24kHz (24 bit / 96kHz WAV)  [10 second WAV] 
     (original version of above clip) (16 bit / 44.1kHz WAV)

Assuming your system is actually capable of full 96kHz playback, the above files should be completely silent with no audible noises, tones, whistles, clicks, or other sounds. If you hear anything, your system has a nonlinearity causing audible intermodulation of the ultrasonics. Be careful when increasing volume; running into digital or analog clipping, even soft clipping, will suddenly cause loud intermodulation tones.

In summary, it's not certain that intermodulation from ultrasonics will be audible on a given system. The added distortion could be insignificant or it could be noticable. Either way, ultrasonic content is never a benefit, and on plenty of systems it will audibly hurt fidelity. On the systems it doesn't hurt, the cost and complexity of handling ultrasonics could have been saved, or spent on improved audible range performance instead.

RobinKidderminster's picture
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RE: Test your hi-res systems performance.

In total ignorance & stupidity can I ask (1) what can I gain from listening to silence (2) If I hear nothing or conversly something then what can I do about it and (3) what might I hear ? 

I thought I knew nuffin'.

Now I know.

I know nuffin'

Cheers

Yamaha V2065. MS Mezzo 5.1 Panasonic 42. Sony BD. Garrard 86SB. WD Live TV. SkyHD.

http://www.whathifi.com/forum/home-cinema/lounge-hc-signature-update-bass-traps

 

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RE: Test your hi-res systems performance.

My cat did not like that

shooter's picture
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RE: Test your hi-res systems performance.

RobinKidderminster wrote:

In total ignorance & stupidity can I ask (1) what can I gain from listening to silence (2) If I hear nothing or conversly something then what can I do about it and (3) what might I hear ? 

I thought I knew nuffin'.

Now I know.

I know nuffin'

Cheers

 

No problem RobinKidderminster.

If you hear nothing then your system if fine for 96khz and 192khz downloads as the test tones above are in the operational area of hi-res. They are not audible to us as humans but the noise created by them (ultrasonics) travels down (or up) the audioband into our listening spectrum.

If you hear any noise at all inc. clicks, whistles or tones then the system when playing hi-res downloads will also add the noises during playback which in turn will degrade the quality of audio playback.  The cheapest way of overcoming them is not to download the material and get the CD equivilent instead, otherwise its a system re-shuffle/build to accomodate the noise caused from ultrasonics. The wider the frequency band of the equipment the better it is to deal with ultrasonic noise that filters down the band so it disapears before it becomes audible. Amps with responces of 5hz upto 30khz for example, DAC's with very high sampleing rates i.e 384khz have plenty of head room but speakers are trickier in that respect with low notes (hz) being more the problem.

It system dependant as each one will react in a different way.

 

shooter's picture
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RE: Test your hi-res systems performance.

MajorFubar wrote:

My cat did not like that

 

Havent tried it with my dog yet but i will.

 

How did you get on with it Major?

SteveR750's picture
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RE: Test your hi-res systems performance.

Hmm, downloaded the FLAC file, tried to open it, an opened the second WAV at the same time. Soem loud warbling ensued...not good I thought. Went through all the WAV files including the first and silence this time. Couldn't open the FLAC file. The only click I get seemed to be when the file was buffering, but I've realised it's some external interference.

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