GR Research B24 AC Cord Review

[voodooless]

I think your view is overly simplistic.

Well yeah, I like simple

Question is: is the process and mechanisms that fills in the hole in our eyesight the same as the one responsible for imagining differences in cables where there are none? Are they both cognition? Or is the second more something that happens after the cognition took place?

Who’s volunteering for an MRI

 

[Andysu]

Is the experience of good stereo imaging the product of imagination or the product of perception? I would argue the latter.

Tom

 

[tomtoo]

Is the experience of good stereo imaging the product of imagination or the product of perception? I would argue the latter.

Tom

I argue both.

 

[5mall5nail5]

Danny will tell you how many twists per inch are in this cable and how he can audibly hear the twists, in 3....2......1.......

 

[mhardy6647]

I had them on bike wiring harnesses 50 years ago but I had no idea they were pants.

Maybe on bikes they were chaps.

 

[Katji]

Maybe on bikes they were chaps.

Good point! ...Village People.

 

[DualTriode]

Agree. But the threshold of audibility depends on the SPL (see the Fletcher-Munson equal loudness contours), so the inclusion of the threshold of audibility should be accompanied by a footnote explaining which curve was chosen and why. This could be in the form of a reference to a "here's how we do things at ASR" page.

Tom

I am a retired M.E. Noise and vibration was much of my work.

It is interesting to me how many people claiming expertise are wrong at least by half.

Cities, counties and other jurisdictions have noise level ordinances.

The typical jurisdiction’s ordinance is based on the weighted dBA scale. For an example my outdoor fan cooled HVAC is limited by the sound level on your side of the fence. It is permissible that you can hear it but it cannot be above a specified level on a weighted dBA level on a SPL meter. This where the ordnance works correctly, this is broad band noise.

The new energy saving HVAC technology has variable speed controls where frequency may vary and emit a varying single pitch, near pure tone, that can and does pierce for several blocks into residential neighborhoods from the rooftop of a 4 story commercial building. That single ~400Hz tone may be well within the maximum allowed on the Inspector’s handheld dBA SPL meter. This is narrow band noise. Still the neighbors will be calling the city council. My friend the Noise and Vibration Engineer and will be out standing in the not so good neighborhood at 10:00 pm.

So is the hiss coming from my mids and tweeters a single pure tone, if not why are we using the Fletcher-Munson Threshold of hearing curve to measure it?

Why are we pasting the Threshold of Hearing Curve on a converted voltage (dBV) FFT plot.

I suppose that it could be a pretty graphic to teach the theory. (with no actual SPL measurements)

In the real world of audible and measurable things we should not be talking about the threshold of hearing until the sound is coming out of the speaker(s).

Thanks DT

 

[Trell]

That single ~400Hz tone may be well within the maximum allowed on the Inspector’s handheld dBA SPL meter. This is narrow band noise. Still the neighbors will be calling the city council

This reminds me of the old site silentpcreview that in addition to noise measurements also did listening tests to check if the fan noise was objectionable.

 

[DonH56]

IIRC, @amirm overlaid the curve relative to 120 dB SPL from his speakers.

 

[amirm]

So is the hiss coming from my mids and tweeters a single pure tone, if not why are we using the Fletcher-Munson Threshold of hearing curve to measure it?

The graph and measurements show mains tone and harmonics which are all pure tone and hence can be directly compared using fletcher munson curve. You can also do this for noise but you have to perform more work to mach the two.

 

[Louie]

All though GR recommends it for preamp, it may be of better to evaluate with use of power amps as it saves a 2V drop with the lower resistance. Most higher quality amps supplies 14ga cables instead of basic 18ga.

 

[DualTriode]

IIRC, @amirm overlaid the curve relative to 120 dB SPL from his speakers.

This is not true.

If measurements were made of the speakers there would be noise and distortions masking everything 40 or 50 dBs (for a good speaker) below the music output.

Also see where @amirm talks about "if the speakers could play that loud without compression. That posted FFT is clearly a electrical voltage amplifier measurement not a measurement made with a microphone. That type of measurement will be in the microphone noise floor you would not see the power supply Harmonics.

The plot is for illustrative purposes no actual microphone measurements were made.

 

[amirm]

All though GR recommends it for preamp, it may be of better to evaluate with use of power amps as it saves a 2V drop with the lower resistance. Most higher quality amps supplies 14ga cables instead of basic 18ga.

Any amplifier that pulls full 15 amp current would come with a thicker cord than the one I tested. Regardless, all that would do at most make a tiny difference in output power. No other change would occur as people claim.

 

[amirm]

This is not true.

If measurements were made of the speakers there would be noise and distortions masking everything 40 or 50 dBs (for a good speaker) below the music output.

Also see where @amirm talks about "if the speakers could play that loud without compression. That posted FFT is clearly a electrical voltage amplifier measurement not a measurement made with a microphone. That type of measurement will be in the microphone noise floor you would not see the power supply Harmonics.

The plot is for illustrative purposes no actual microphone measurements were made.

No, it is very true. Don understands it but you don't. Did you read the AES papers I listed for you yet? Until you do, you will continue to be totally confused about this topic.

I will give you another hint on why you are way off the field. A perceptual codec like MP3/AAC, etc. use threshold of hearing to set level of quantization as the compress audio. You think they don't work either because no microphone or speaker is involved?

 

[sonitus mirus]

Nice plug!

Not the B24, but for the artist, Radical Face. Good stuff!

Thanks for sharing.

 

[amirm]

Agree. But the threshold of audibility depends on the SPL (see the Fletcher-Munson equal loudness contours), so the inclusion of the threshold of audibility should be accompanied by a footnote explaining which curve was chosen and why. This could be in the form of a reference to a "here's how we do things at ASR" page.

The key technical information was provided in the graph. This is not something I commonly do so don't see the reference to "how do things as ASR." It also has nothing to do with how we do things. That is the method that is used to perform audibility analysis in research papers published at AES.

I highly suggest people read this paper if they want to learn about this topic:
“Dynamic-Range Issues in the Modern Digital Audio Environment, ” Fielder, Louis D., JAES Volume 43 Issue 5 pp. 322-339; May 1995

Simply put, to have a dynamic range of 120 dBSPL, everything in the recording and playback chain combined must have that dynamic range. As a result, you can analyze each component to see if it meets or exceeds that criteria. If it does not, then when playing back with a peak of 120 dBSPL, system noise can land above threshold of hearing and therefore be audible. This requirement however only applies to the most sensitive part of our hearing. At lower frequencies we can tolerate far less dynamic range as explained in my article: https://www.audiosciencereview.com/forum/index.php?threads/dynamic-range-how-quiet-is-quiet.14/

And graph within (which came from Fielder's work):

As it relates to this topic, see how Fielder uses this analysis to see if microphone noise would be audible:

Stuart's paper is also a great read:
“Noise: Methods for Estimating Detectability and Threshold, ” Stuart, J. Robert, JAES Volume 42 Issue 3 pp. 124-140; March 1994

He too uses this kind of analysis to determine audibility of quantization noise of digital audio formats.

Finally, I cover these concepts and more of Fielder's work in this video I produced:

So no, this is not some made up concept. I have explained it before many times and can do it again if questions are asked instead of complaints.

 

[gfx_1]

What's the average gauge of modern Romex cable in the walls in the USA? Would using super low gauge power cords even matter if Romex cable gauge is higher? I suppose if you had to use a super long extension cord, the lower the gauge the better.

Edit: Just realized this cable is actually 14awg with a huge amount of insulation.. can get a Tripp-lite 14awg 3 footer for less than $7

Stud pack on youtube has some videos on romex installation usually 12 and 14 AWG.

We use 2.5 mm2 wires (brown = live, blue = neutral, and yellow/green = earth) in a plastic 19mm tube from the switchboard to the sockets, switch lead for lamps is black 1.5 mm2 wire.

You can calculate the voltage drop. An IOTAVX SA3 does 21 Watt at a louder than normal volume say 0,1 Amp at 230V, the voltage drop on even a 10 m cable is negligible https://www.omnicalculator.com/physics/voltage-drop

 

[amirm]

Don't be too hard on yourself. Your experience fits squarely with expectancy bias. You expected the better cable to sound better so you perceived it that way. That's not due to a failure of memory of perception in my view. Perception is sensing + brain involvement.

While what you say is true, it doesn't explain many cases of people's experiences in this regard. For example, you often hear a person say "I didn't expect to hear any difference but I did!" Clearly no expectation bias there. This actually happens to me at shows all the time.

The explanation has to do with the fact that we hear differently depending on intent. We make a change in the system -- plug in a new power cord -- and then listen intently. All of a sudden we hear a lot more detail. Space opens up between notes as we focus on smallest detail to detect differences. We then hear bass more clearly. Veil is clearly removed. Now, and only now, expectation bias sets it as we associate the change to what we did to the system. We put in the old cord ready to be unimpressed and we are.

The above is quite insidious because far fewer people are aware of it than people who have heard of "expectation bias." This is why accusation of expectation bias doesn't stick and people continue to believe in what they do.

 

[formdissolve]

While what you say is true, it doesn't explain many cases of people's experiences in this regard. For example, you often hear a person say "I didn't expect to hear any difference but I did!" Clearly no expectation bias there. This actually happens to me at shows all the time.

The explanation has to do with the fact that we hear differently depending on intent. We make a change in the system -- plug in a new power cord -- and then listen intently. All of a sudden we hear a lot more detail. Space opens up between notes as we focus on smallest detail to detect differences. We then hear bass more clearly. Veil is clearly removed. Now, and only now, expectation bias sets it as we associate the change to what we did to the system. We put in the old cord ready to be unimpressed and we are.

The above is quite insidious because far fewer people are aware of it than people who have heard of "expectation bias." This is why accusation of expectation bias doesn't stick and people continue to believe in what they do.

Same goes with camping in the woods, or hiking at night. You hear a twig snap in the distance - suddenly you focus and can hear everything.. even phantom twigs snapping, or growls, or feet etc..

 

[DonH56]

My early DBTs (decades ago) showed me (and others) that almost every time I heard "something new", when I switched to the old system and repeated the test, I discovered it was there all along. Just a matter of focus when listening.