The edge of audibility

[Robert]

I'd certainly expect it to be audible as it's a measurable difference, i.e. the impedance of the dedicated spur will be difference to the daisy-chaned reels. If nothing else you'll be running the signal through three additional fuses.

Tony.

PS in the dim and distant past I've been able to reliably blind-test a hefty self-built fuseless (i.e. unsafe / illegal) IEC lead made from heavy grade twin and earth vs. a stock mains lead.

Ok, I'll do it over the next couple of days.

- Standard from spur
- Daisy chained reels
- something utterly bonkers and insane just for a laugh, probably involving sweet wrappers.

Pics, measurements, and files to play and examine.

We'll put the pre, power amp and dac on each version.
Speakers playing at a decent volume to generate some vibration. This will also modulate the current drawn from the mains.
I'll use a digital source for best consistency.

Happy to amend.

 

[sq225917]

Not being one to beat around the bush, but frankly Robert you're talking bollocks. Do you only listen to your hifi after midnight when everyone is in bed and there's no cars moving within ten miles of your house?

Do you ask them to turn the air-con off at your local concert venue?

No of course not.

The microphones picked up exactly what was to be heard in the room, there was no obvious noise from outside, in fact at no point with music on or off was I ever aware of any external noise. The loudest thing in the room is the fan in Steven's pre-amp which hugely drowns out anything that might be going on inaudibly outside.

You can call it null and void if you like, people expect no less, but the truth is that this reflects what people hear in their own rooms when trying these sort of things out for themselves. I don't think to make sure there are no cars going past when i plug in an upgraded power supply to my DAC to see if I can hear an improvement so frankly what you claim for background noise making it null and void is laughable.

The test was never intended to utterly isolate all variables that might lead to a different sound, if it was I would have hired an anechoic chamber from the afternoon from the ENG dept at Sheffield Uni. Even then all that would have told us is what it sounded like in an anechoic chamber and nothing about what the sound in steven's room was like.

I'm not looking for a wider applicable scientific truth or understanding, just proving beyond reasonable doubt that there is a difference to be heard, or not, in Steven's house with the methodology and gear used.

 

[Robert]

Not being one to beat around the bush, but frankly Robert you're talking bollocks. Do you only listen to your hifi after midnight when everyone is in bed and there's no cars moving within ten miles of your house?

Do you ask them to turn the air-con off at your local concert venue?

No of course not.

The microphones picked up exactly what was to be heard in the room, there was no obvious noise from outside, in fact at no point with music on or off was I ever aware of any external noise. The loudest thing in the room is the fan in Steven's pre-amp which hugely drowns out anything that might be going on inaudibly outside.

Your argument makes no sense Simon.

To answer your points in order:

- How we listen is beside the point, but listening for enjoyment as opposed to performing a test to isolate a particular effect impose quite different demands. You are trying to show that mains effects are altering the sound of the system. To do that with any degree of reliability you must present both recordings such that the only difference is the mains effect. You have not done so and that is unarguable. You have stated that no difference was heard in the room at the time, so we assume what you were trying to hear was at best, very subtle.

- Low level background noise is rarely obvious. The figures I gave earlier were in what appeared to be a silent room. You'd expect a static SPL under such conditions, not a 17dB difference. Given that you were listening in the room at the time of the recording, you'd not have noticed low level background noise but your mic will have recorded it. Its called masking.

- The files you've recorded show a difference. Being equally blunt, you've left one massive variable in play that means no meaningful result can be taken from your test. You've introduced more questions than you've answered.
To A/B in a room, live and ideally blind, you would normally make many comparisons and not rely on one alone. This minimises the chance of spurious noise influencing the overall outcome. Here we are asked to rely on only one A/B pass, which is fine if there is no room effect, ie you used line.

I'm frankly astonished you didn't take a line out.

Despite all of that, this is very useful.
It would at least appear to support the view that digital recorders, even when hampered by a live acoustic and a (built in?) mic can capture small differences from wherever they come. Thats progress in my book.

 

[cooky1257]

Slight difference but admit over computer speakers it tends to shift about, I could for example swear the hollowness of the drum intro was more pronounced on one but it was never consistent enough-strange.

 

[dave]

No of course not, but by making a test extreme, ie a stretch test, you make it pretty unlikely someone will have a system that bucks the result.

The sum resistance of all those adaptors and cables is way higher than anyone would typically encounter even with a crappy thrift store block, not to mention all of those fuses and connections.
You would surely expect to both hear and see something. Masses of potential for dirty contacts, RF pick up, and even Steven's vibration theories to manifest themselves.

I don't know the result Dave - I've never tried it. Might be fun.

LOL..I say go for it;-)

Btw, you'd be proud of me, my repair shop just did chocolate wrapper surgery on my CDS2's Burndy as one of the wires broke deep inside the cable resulting in no output from the CDP. They carefully pulled unused wire from both ends of the cable bundle and soldered extensions to bridge to the Burndy pins. It not only worked but was far more sensible and cheaper than replacing an otherwise, perfectly good Burndy.

Anyway, I have extra joins in my primary source component's wiring now and the damn thing sounds possibly better than when it was new;-)

 

[Robert]

Excellent Dave

You have to be careful these days though.
The sods are scrapping proper foil wrappers and replacing with that plastic foil look-a-like stuff

 

[dave]

;-)

 

[darrylfunk]

you lot sort this out i'm just gonna carry on listening to music if you think order of appliances is important to you - fine....

i will never be obsessed enough to even check it beyond basic engineering protocols cos' even the daftest most obsessed amongst you know that this 'improvement' is minuscule compared to room acoustic issues or slightly worn styli or even feeling a bit off colour with a cold....or having to switch the gear of for 5 mins while switching wires....hence why many of the audio experts in here are also connoisseurs in whisky,car,movie,politics,economics,camera,watches,fountain pen,sport,women,art,real ale,food,knives,wine,drama and numerous other male obsessive 'life' categories....it's worrying really.

dave is excluded cos' he has perfect golden ears cos' it took him a lifetime of naim upgrades to discover the musicality of bob dylan.

we are working around the clock to get dave 'into' miles davis's difficult period now....

 

[dave]

you lot sort this out i'm just gonna carry on listening to music if you think order of appliances is important to you - fine....

i will never be obsessed enough to even check it beyond basic engineering protocols cos' even the daftest most obsessed amongst you know that this 'improvement' is minuscule compared to room acoustic issues or slightly worn styli or even feeling a bit off colour with a cold....or having to switch the gear of for 5 mins while switching wires....hence why many of the audio experts in here are also connoisseurs in whisky,car,movie,politics,economics,camera,watches,fountain pen,sport,women,art,real ale,food,knives,wine,drama and numerous other male obsessive 'life' categories....it's worrying really.

Darryl,

Last time I checked we were in a hifi forum. Perhaps I'm wrong but I don't recall Tony setting standards on what could or could not be discussed on the subject. If we're discussing something other than room acoustics, worn stylii, or whatever makes you happy, there's always the option to ignore the thread.

On the other hand, I didn't realise you ranked gear warm-up at all. Assuming you weren't being facetious, you should start a thread on the subject. I'll participate with a report on my CDS2 changing after it warms up over the next four days as it's just back from service.

FWIW, even stone cold it's kept me spinning disks and I've only stopped listening due to severe thunderstorms passing through. I'm a bit of a weather connoisseur so...

best,

dave

 

[Joe P]

Dave,

You get Star Trek so you're obviously not beyond redemption.

We reach, man.

Joe

 

[dave]

Thanks for confirming my seat on the Glory Train, Joe.

 

[dave]

we are working around the clock to get dave 'into' miles davis's difficult period now....

That will never, ever happen. I can't stand the thought of an electric piano and find synths in almost every form of popular music a complete bore and total waste of electricity. You don't want to get me started on the genre known as Fusion.

 

[Joe P]

Dave,

Step right up.

Joe

 

[dave]

Solid Jackson, solid.

Who needs God when we have Waits?

 

[sq225917]

Rob, the reason I couldn't hear any difference in the room is simple enough, it took minutes to swap between cable positions. At home playing the samples I can flick between them instantly.

You've been presented with what was heard and recorded in the room. The entire point of the exercise was to do that, 'present what was heard in the room' warts and all. The reason I didn't take a line out is because that would have reduced the number of items in the chain and minimized any 'compounded effect' due to the swapping all the cables over.

I'd appreciate it if you would start your own test thread to discuss different methodologies and present your own files. I'm happy that what was recorded matches what was heard in the room exactly and that the way the files have been presented here help eliminate the adverse effects associated with the delay in swapping the cables over.

We disagree on the effects of background noise, if you want to prove that the background noise is the cause of the differences then you'll need to go to Steven's and repeat the experiment exactly, but late at night. If you don't do that all you'll be proving with a negative result is that the set-ups used for the two experiments were different.

 

[Re-Joyce]

Robert,
I know you are very keen on scientific rigour rather than enjoying the journey but to dismiss this test is insane - it is what 95% of HiFi purchasing is based on and therefore has to represent one way to measure the systems performance. I can't believe that if you were designing a pre-amplifier you wouldn't listen to it against a reference rather than / as well as recording its outputs.
Besides a line out recording would remove the power amp which is likely to be most affected by any changes in the mains imo.


cheers
Jason

 

[muzzer]

Si
Did you compare the mains block on the floor as opposed to its own dedicated shelf?

 

[Tony L]

Would it be possible to make a box with a couple of big resistors or whatever in it to enable direct recording of the speaker outputs? Given that I've got a similar box, a thing called a Can Opener, that enables me to plug my headphones into the speaker outs I'd have thought this wasn't too much of a stretch. I find the Can Opener very useful indeed for fault finding as I can easily remove the speakers and room from the picture. This wouldn't be any improvement for Steve and Simon's test as their theory appears to be vibration, but for Rob's test it would be ideal as it would get the power amp into the equation, i.e. the thing that draws the current.

Tony.

 

[Patrick Dixon]

I think the problem is that the more you change the test away from actual listening conditions, the more likely you are to lose the validity of the result.

A box with resistors wouldn't replicate a speaker load, because a speaker load is not just resistive. You also have back emf, acoustic feedback and stuff, so you need to run a real speaker in a real room to get a real result.

 

[Tony L]

I'm just conscious that with Rob's forthcoming test the thing most likely to show up the change, the power amp, will not be in the system!

Tony.