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The edge of audibility

After listening to the two files...


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what's strange about that?

have not seen much of a serious report, just a nice friendly listen....neither simon or steven have stated anything about improvements really....it was just a nice little session - what are you trying to prove by making statements neither you nor i were there so why does it matter so much to you....what are you arguing a point for?
and why haven't you commented on the fact that block or wall didn't seem to make a difference?

Peace brother, we're all having a friendly chat. I think it's great two opposing members got together to sort this out with a real test instead of arguing in a forum about the same old stuff.
 
The band of recovering audioholics seem pretty quiet....

My reading of this is:

- Mains filters that change mains impedance can produce a difference.

- Cable/socket swaps don't.

No surprise at all.

One has some credible science to back up the findings, the other doesn't.

You cannot compare using in room mic recording for the reasons already covered. It must be line out.
Regarding wanting to capture the effect of speaker vibration - you still would via line out. Think about it!
 
Robert, you are clutching at straws - and are craving a nul result.

Why?

Moreover, swapping between the block and wall could effect an impedance change. Indeed one of the four wall sockets measures a slightly lower impedance than the other three. The filter otoh has two identical sockets but one is just slightly nearer the inlet. The swap there was simply between the two.
 
Robert,

I've experienced a small but audible improvement in sound when placing a power amp up first in a strip's outlet sequence vs last (no filters in the strip.) How could that be since we're talking alternating current?

regards,

dave

P.S. I consistently imagine this ...just to qualify;-)
 
The important thing was to go into the experiment with a completely open mind regarding the outcome. Meeting Simon he was completely open-minded as was I. There really is no point otherwise.

If you are a recovering audioholic your mind is closed. Your hi-fi journey was clearly a fretful one. Apart from enjoying the music I regard my hi-fi journey as ongoing and a source of fascination and wonder. I think the cynics regard it more with bewilderment and a sense of uncertainty from which they feel a need to escape.

Robert you clearly fall into this category. Your experiments attempt to prove a certain belief and are therefore not conducted with an open mind.

Another thing that I was reminded of during the course of Simon's visit is that by and large we tend to hear the same. What differs is the imperfections we tolerate and the compromises we make with our systems in accordance with our individual priorities.

Joe Hutch often states that we hear things differently. I disagree. We simply prioritise differently.

For me timing is the most important and to a lesser degree texture and harmonic structure.

Simon seems to prioritise tone and hears the tonal imperfections of my speakers/room that I also hear but they bother me less.
 
interesting that dave cos' 2 naim dealers i know say that the power amp or item that draws the most current should be the furthest up the chain on mains due to it 'pulling' more thus their logic is the source components get the better sounding position.... :(
 
Robert, you are clutching at straws - and are craving a nul result.

Why?

Moreover, swapping between the block and wall could effect an impedance change. Indeed one of the four wall sockets measures a slightly lower impedance than the other three. The filter otoh has two identical sockets but one is just slightly nearer the inlet. The swap there was simply between the two.

Not at all.

In fact.....

I do hear a difference between those two samples even on my shitty OP amp filled equipment.
Takes me about 40 plays and I consider the difference to be below any level of significance, ie I cannot group my findings in any way such is the magnitude of the difference and randomness of the result. Certainly not significant enough to form a reference. TBH, my mood gives more subjective difference.

More to the point, following the listening with a spectral analysis shows the files are in fact a little different - a dB or two different in some very select places and matched very closely in others. This you might expect from a noisy environment - not from a tiny change to mains impedance.

But you simply cannot compare files recorded in a live and noisy environment.
I live well off the main roads. If I make two 'silent' recordings and then examine them, I assure you they'll be quite different, with random noise perhaps no lower than the low 30s dB.

I just ran my level meter for 5 minutes.
Levels in a silent off-road room ranged between 32-48dB.
Even fidgeting quietly in the chair registers.

Sorry to state the obvious but making recording over that will never give you 'identical' files.

Your test is very interesting, I've enjoyed listening to the results, and good on Simon for going along. It is however, seriously flawed.

I'm pleased to see that you are now at least embracing science :)
 
Not at all.

In fact.....

I do hear a difference between those two samples even on my shitty OP amp filled equipment.
Takes me about 40 plays and I consider the difference to be below any level of significance, ie I cannot group my findings in any way such is the magnitude of the difference and randomness of the result. Certainly not significant enough to form a reference. TBH, my mood gives more subjective difference.

More to the point, following the listening with a spectral analysis shows the files are in fact a little different - a dB or two different in some very select places and matched very closely in others.

But you simply cannot compare files recorded in a live and noisy environment.
I live well off the main roads. If I make two 'silent' recordings and then examine them, I assure you they'll be quite different, with random noise perhaps no lower than the low 30s dB.

I just ran my level meter for 5 minutes.
Levels in a silent off-road room ranged between 32-48dB.
Even fidgeting quietly in the chair registers.

Sorry to state the obvious but making recording over that will never give you 'identical' files.

Your test is very interesting, I've enjoyed listening to the results, and good on Simon for going along. It is however, seriously flawed.

I'm pleased to see that you are now at least embracing science :)

Can I just check that you are basically saying that any test relying on listening to the system is worthless as background noise variations are too large, or are you saying that just this test is worthless as the differences are too small compared to a typical variation in background noise?

cheers
Jason
 
I wasn't expecting to hear any difference but what I found odd was that on the first listen of the second track it immediately sounded clearly very different, better, more dynamic - louder even. Then switching back and forth revealed those all those clearly perceived differences to be largely imagined. Curious.

I wouldn't be able to choose one over the other and when a difference isn't clearly apparent it doesn't really interest me as an investment, I'd be happy with either.

However there is a difference according to the diffmaker application and one that seems to cover a specific part of the spectrum.

Whether it is revealing more of the source or not isn't clear though.

---

It would have been interesting to hear a third track - a duplicate of either of the first two to see if there is any audible in room difference in the recordings we know to be the same.
 
Can I just check that you are basically saying that any test relying on listening to the system is worthless as background noise variations are too large, or are you saying that just this test is worthless as the differences are too small compared to a typical variation in background noise?

cheers
Jason

I'm saying that this test seeks to isolate certain effects only.
To do so you must present each case, in this case a recording, from a completely level playing field. This test fails because a live in-room recording does not remove background noise - you will always get two different recording even if the sound from the system is identical.
Short of doing the rest in an anechoic chamber, in the middle of nowhere, with nobody in the room, you will never produce identical files.

This simple effect could have been eliminated by taking a line from the amp and eliminating external noise variations. I did suggest this days ago.
The counter argument is that Steven wanted to include the effect of speaker vibrations. A line out would still do that.
If speaker vibrations are having some effect on the mains, that effect is still piggy-backed onto the audio signal as it passes through the system so long as the speakers are playing. Think of how TT feedback works....

Had differences emerged via line out, I would be very interested indeed in what measurable differences there might be on Steven's various mains sockets.

As it is, we have isolated nothing and demonstrated nothing.

If Someone wants to set up a blind session with a few participants I'm well up for it, so long as there is some basic housekeeping.
For the record, I'm not saying that mains impedance differences cannot be audible in some situations and have never said this. I certainly wouldn't worry about it though.
 
interesting that dave cos' 2 naim dealers i know say that the power amp or item that draws the most current should be the furthest up the chain on mains due to it 'pulling' more thus their logic is the source components get the better sounding position.... :(

There's been a discrepancy for years between some in the UK and US. Generally most in the US I've spoke with favor reverse hierarchy (power amp first, source last.) The best any of us could come up with is differences in power infrastructures. FWIW, most of the chaps at Salisbury I’ve spoken with prefer power amps first as well.

In my experience it’s not huge nor is it that important as I’ve personally had my preference change depending on program material. If I stop thinking about it and try it both ways for a week at the time, I always end up with power amp first again. I’ve left it that way for sixteen years now.
 
There's been a discrepancy for years between some in the UK and US. Generally most in the US I've spoke with favor reverse hierarchy (power amp first, source last.) The best any of us could come up with is differences in power infrastructures. FWIW, most of the chaps at Salisbury I’ve spoken with prefer power amps first as well.

I've always been power amp first too, though it amazes me that none of these absurdly expensive audiophool plug boards (one of which I have) have come up with a solution where all sockets have an even weighting - surely starring everything back to a single point would address the issue? My setup runs amp, phono stage, CD player, turntable. The amp, being a tube job, draws way, way more than anything else in the system. In the TV system the 303 gets it's own wall socket, everything else goes via a cheap plug board, but the pre is a passive there.

Tony.
 
I've always been power amp first too, though it amazes me that none of these absurdly expensive audiophool plug boards (one of which I have) have come up with a solution where all sockets have an even weighting - surely starring everything back to a single point would address the issue? My setup runs amp, phono stage, CD player, turntable. The amp, being a tube job, draws way, way more than anything else in the system. In the TV system the 303 gets it's own wall socket, everything else goes via a cheap plug board, but the pre is a passive there.

Tony.

Tony, a true star arrangement would sort it.
However you do have to ask yourself, seriously, would oh say <0.0005 ohms in series with the mains and street wiring worry you? :)
 
I've always been power amp first too, though it amazes me that none of these absurdly expensive audiophool plug boards (one of which I have) have come up with a solution where all sockets have an even weighting - surely starring everything back to a single point would address the issue? My setup runs amp, phono stage, CD player, turntable. The amp, being a tube job, draws way, way more than anything else in the system. In the TV system the 303 gets it's own wall socket, everything else goes via a cheap plug board, but the pre is a passive there.

Tony.

The whole thing beats me as well (it's freakin' alternating current.) I've tried star wiring w/just ground and then with the neutral and hot and still find a difference (and prefer) the bog- standard cascade arrangement we'd normally use with any appliance here in the US.

Oddly, the star arrangement with all conductors here in the US sounds the worst to me whereas as many comrades in the UK (inc. naim employees) prefer a star arrangement. So much for expectation bias;-)

Interestingly (or not), preamp and source sequencing here seems to make little difference. The only significant change IMO is with power amp at beginning or end of chain.
 
The whole thing beats me as well. I've tried star wiring w/just ground and then with the neutral and hot and still find a difference (and prefer) the bog- standard cascade arrangement we'd normally use with any appliance here in the US.

Oddly, the star arrangement with all conductors here in the US sounds the worst to me whereas as many comrades in the UK (inc. naim employees) prefer a star arrangement. So much for expectation bias;-)

Interestingly (or not), preamp and source sequencing here seems to make little difference. The only significant change IMO is with power amp at beginning or end of chain.

Dave, you worry too much :)

I have an Olson 10 way block fixed to the wall and this runs back to a dedicated spur on the consumer unit via heavy cable - I think the stuff used for cooker mains, so about 6mm conductors. About 5m of cable. The sockets in the Olson are joined via very thick brass runners.
Compared to what sits behind this, so the wiring to the street and back to the local sub station (about 200 yards away - I'm lucky) and of course the impedance of the step-dowm transformers, this is nothing at all.

It matters not one jot the order in which things are connected to the block.

Very good article on Martin Clark's Acoustica site on mains impedance and what really matters.

If anyone is interested we could try something pretty extreme.
I have about 3 reels of cable here with sockets, all around 5-10 in length of the type used to power things in the garden.
We could:

- make a digital recording of the system playing with amplifiers powered via short mains leads, from the dedicated spur.

V

- all of the lawnmower extension cables connected and plugged together in series, connected to the socked in my bathroom at the far end of the flat. Very long flat - as I'm sure Tony can verify :)

Make 2 files, listen, and look at the results (with no background noise...)
 
Trust me Rob...I've lost no sleep whatsoever over it. I just find the whole thing consistently odd ;-)

I've done away with powerstrips altogether as discovering super-tight wiring connections w/standard wall outlets triumphs any strip heard so far.

P.S. quite familiar with Martin's excellent site.
 
If anyone is interested we could try something pretty extreme.
I have about 3 reels of cable here with sockets, all around 5-10 in length of the type used to power things in the garden.
We could:

- make a digital recording of the system playing with amplifiers powered via short mains leads, from the dedicated spur.

V

- all of the lawnmower extension cables connected and plugged together in series, connected to the socked in my bathroom at the far end of the flat. Very long flat - as I'm sure Tony can verify

Make 2 files, listen, and look at the results (with no background noise...)

If no difference were found, would that neccessarily prove any and all systems should react the same?
 
Joe Hutch often states that we hear things differently.

I don't actually remember stating that, but it seems non-contentious to me. If I hear, say, free jazz or atonal classical music, it sounds like a noisy mess to me, but I'm sure others hear it differently. Younger people will hear things differently to older people, those with musical training will hear things differently to those with 'uneducated' ears, someone with perfect pitch will be more bothered by less-than-perfect singing than most of us.
 
If no difference were found, would that neccessarily prove any and all systems should react the same?

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.
 
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.
 
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