Is the entire audio industry a fraud?

[DrCWO]

How about showing the ABX comparator unit itself, not some vague description of a ficticious device buried in your basement, and the show the unit you claim to have taken to your friend's place for the other ABX test you claimed to have completed.

I'm calling absolute bullshit on your claims.

Put up or shut up.

Seems you are a quite unpolite, unpleasant and upset man
Why not asking me friendly to show what I did after my post?

I‘m traveling in South East Asia till end of April so I‘m not able to shoot and send photos. So at the moment you can believe me or not I don‘t care at all.

Here you can see my full range horns I was talking about but I think it won‘t increase my credibility in your brain…

Showing (off) your Roon setup - description and photos [2021 .. 2022]

Thanks to @David_Snyder for mentioning my thread here. So I like to take the chance to show my setup here too Hidden in the basement directly below the sideboard Roon Server on Gigabyte BRIX GB-BACE-3160 Mini-PC (Intel Celeron, 8 GB RAM, 2TB SSD) operated with Win10. In the Roon DSP I...

community.roonlabs.com

Edit:

This is the NCx500 Amplifier I bought. I ordered a custom build with one power supply only as the full range drivers have 16Ohm so I need voltage without much current.

STUDIO N-7x| Rouge Audio Design | Roma

HYPEX NCx500 Hypex Ncore serie X

en.rougeaudiodesign.com

 

[Newman]

Sorry, I try to give a short reply as it off topic here
Here the steps I took to make the ABX as fair as possible:

• I calibrated the horns independently for each amplifier to the same target with the Acourate software. This is important as using a resistor in series to the full range speaker the rising impedance of the chassis increases sound level towards the higher frequencies.
• As the Krell has a much higher amplification than the NCx500 (26 to 11dB) I calculated a voltage divider with tree resistors and soldered it in the XLR plug I connected to the Krell. I used a Y-cable to send the same audio to both amplifiers.
• After that I did another measurement with my Earthworks measurement mic to check the volume (at the listening position for both channels) and adjusted the voltage divider so both amps produce the same volume in a range of +-0.2dB.
• For ABX I wrote a small program in node.js for a Raspbarry Pi controlling eight relays that connect the speaker cables to one of the amplifiers only. The PI and the relays were in my basement so I could not hear any click of them, same as the amplifiers. The software disconnects the speakers for 50ms before reconnecting it so I know that they got switched.
• On my iPad I was able to start ABX via the browser during playback from Roon. Each single ABX comparison was started manually and switching from A to B to X also. So I was able to repeat the track I heard after switching.
• I ran it 10 times with 15 ABX each time with different musical material.

At the end I got a correct result of 10 out of 10 correct answers for all 15 rounds

Maybe there was some issue in my setup or methodology I did not think about so I would appreciate your comment.

Best DrCWO

Further checks I would suggest are:-

1. Don’t level match using a mic at the listening position. Instead, do it using a voltmeter at the loudspeaker terminals with a 1 kHz sine wave tone. Much more accurate and repeatable.
2. Do the above with each speaker separately, if listening in stereo during the tests. It is possible that one or both of your amps have a left-vs-right channel mismatch.
3. Measure the frequency response of the signal at the loudspeaker terminals, with each amp connected in turn. It is quite possible that your particular specimens of the two amps don’t have the same frequency response when connected to your speakers, and the difference is large enough to be audible. In other words, your specimens might not be in perfect working order and have the exact frequency response of perfect specimens of those amps.

 

[MarkS]

After that I did another measurement with my Earthworks measurement mic to check the volume (at the listening position for both channels) and adjusted the voltage divider so both amps produce the same volume in a range of +-0.2dB.

This is not precise enough. An overall level change of 0.2dB is audible (though usually perceived as a quality difference rather than a volume difference). Matching must be done by electrical measurement at the speaker terminals, as Newman has already pointed out.

 

[DrCWO]

1. Don’t level match using a mic at the listening position. Instead, do it using a voltmeter at the loudspeaker terminals with a 1 kHz sine wave tone. Much more accurate and repeatable.
2. Do the above with each speaker separately, if listening in stereo during the tests. It is possible that one or both of your amps have a left-vs-right channel mismatch.
3. Measure the frequency response of the signal at the loudspeaker terminals, with each amp connected in turn. It is quite possible that your particular specimens of the two amps don’t have the same frequency response when connected to your speakers, and the difference is large enough to be audible. In other words, your specimens might not be in perfect working order and have the exact frequency response of perfect specimens of those amps.

Thanks‘ for your feedback.
Did matching separate but not with a voltmeter. Also frequency measurement for equalization can be done at the speaker terminals instead with the mic as I did.
Good hints I'll respect next time I do ABX