Interesting 'white paper' from QED
- Thread starter Sue Pertwee-Tyr
- Start date
Craig B
Re:trophile
Yes, but obviously not as unbelievable as your next years cryogenically frozen* version.
Wasn't it Peter Walker who said 'the best kind of speaker cables are those that conduct electricity'?
*assuming the appropriate heath and safety precautions are adhered to during 'the laying on of hands'.
martin clark
pinko bodger
Shhh. I've got to commission & dedicate a new audio-altar first.
(will look remarkably like a small Chinese granite surface plate. No expense spared, eh...)
(will look remarkably like a small Chinese granite surface plate. No expense spared, eh...)
DANOFDANGER
pfm Member
I have had many cables with various geometries, there does appear to be differences. But these differences are almost always worse. The more complicated the design the more wrong it appears to be. I recently did a review of a few speaker cables with different geometries. However i compared all cables to a more true to source reference rather than the unreliable cable vs cable method. Read more about it here.
The nordost flatline was the key to my ignition for recognising that cables could sound different. But what i did not know until later was that these differences were almost always worse. The standard zip cord was more closer to a direct connection than most of the other cables that claimed superiority. I spent a good while on transmission line theory and related areas to further understand what could cause this phenomenon. After a long while i seem to have settled on time domain distortion. However there is no solid evidence. The facts are that cable geometry does effect the electrical parameters. Where the disconnect is, is what level is perceivable.
The same problem occurs with digital filters in digital to analog converters. Issues are quite aparent but as far as discussions go, theory does not support its audibility. And i quite agree. But nevertheless, its there.
The nordost flatline was the key to my ignition for recognising that cables could sound different. But what i did not know until later was that these differences were almost always worse. The standard zip cord was more closer to a direct connection than most of the other cables that claimed superiority. I spent a good while on transmission line theory and related areas to further understand what could cause this phenomenon. After a long while i seem to have settled on time domain distortion. However there is no solid evidence. The facts are that cable geometry does effect the electrical parameters. Where the disconnect is, is what level is perceivable.
The same problem occurs with digital filters in digital to analog converters. Issues are quite aparent but as far as discussions go, theory does not support its audibility. And i quite agree. But nevertheless, its there.
Craig B
Re:trophile
Well, there does generally seem to be an undercurrent of religion to these cable threads.
As those who consider themselves as 'American Christians' (as opposed to generic Christians) appear to have made a verb out of the word fellowship, as in, former Alabama state senate contender Roy Moore's wife claiming that they 'fellowship with Jews' last week, perhaps these cable threads should be referred to as 'Fellowshiping with Cable Evangelicals' or some such? That way, those whom are so inclined may conduct their praises of the almighty conduit of the Lord their saviour without fear of resistance. The question remains, does the general none-directional population of pfm have the capacity to change polarity wrt the cold treatment of those individuals hoping to fellowship in the same circuit?
As those who consider themselves as 'American Christians' (as opposed to generic Christians) appear to have made a verb out of the word fellowship, as in, former Alabama state senate contender Roy Moore's wife claiming that they 'fellowship with Jews' last week, perhaps these cable threads should be referred to as 'Fellowshiping with Cable Evangelicals' or some such? That way, those whom are so inclined may conduct their praises of the almighty conduit of the Lord their saviour without fear of resistance. The question remains, does the general none-directional population of pfm have the capacity to change polarity wrt the cold treatment of those individuals hoping to fellowship in the same circuit?
A amplifier is a PSU designed to drive a dynamic load with a reference signal (music etc,)
When I designed large PSU's that drove a load some distance from the PSU we used feedback which was also connected to the load. Using the power and the return connections.
This allowed the PSU to produce the correct voltage and thus current at the load.
Unfortunately when this was done with Hi-fi Amps the general public hated the extra trial of cable doing the sensing, wives said it looked crap etc.( I did this at Inca Tech)
Now stuck with this problem of looks and correctness we use two conductors only to drive each load (speaker) and we still get moaned at, "wire do we have to have wires", but we live with it somewhat miffed that our music is crushed to death and we hear a fax of the true possible performance (peace at home) . Some of us moved on to good performance cable at a cost and other went for bling and garbage at more costs.
Time domain (phase) and BW and impedance and current capability of the cable and the amp should be in tune with each other but not all amp designers design cables not all amps designer see the amp as a PSU, but I do.
Along came TQ and in time added bling to add to the TQ with a dab of mystery magic (yer right).
Our new cable has no bling no pink fairies and no extreme profit making but a cable designed to work with a dynamic PSU or a good amp. And not adding to the amp evil loads and random noises and as pure as it can be for a price some can afford not just the bling hunters.
Ok some will hear a better sound some will hear no change but I am now 64yrs old I can still hear up to 18KHz my brother can't hear past 7KHz he also can't detect image. Oh the point is we are all not clones based on a perfect human, some of us are Martians.
Test your self try "One Night In Paris" from 10cc
see if when the bike and bell go by your head and behind you, and with just 2 speakers in front of you can you hear it ?? (phase guys phase) A well set up system will bring Paris to life in you home but watch out for the cars please.
When I designed large PSU's that drove a load some distance from the PSU we used feedback which was also connected to the load. Using the power and the return connections.
This allowed the PSU to produce the correct voltage and thus current at the load.
Unfortunately when this was done with Hi-fi Amps the general public hated the extra trial of cable doing the sensing, wives said it looked crap etc.( I did this at Inca Tech)
Now stuck with this problem of looks and correctness we use two conductors only to drive each load (speaker) and we still get moaned at, "wire do we have to have wires", but we live with it somewhat miffed that our music is crushed to death and we hear a fax of the true possible performance (peace at home) . Some of us moved on to good performance cable at a cost and other went for bling and garbage at more costs.
Time domain (phase) and BW and impedance and current capability of the cable and the amp should be in tune with each other but not all amp designers design cables not all amps designer see the amp as a PSU, but I do.
Along came TQ and in time added bling to add to the TQ with a dab of mystery magic (yer right).
Our new cable has no bling no pink fairies and no extreme profit making but a cable designed to work with a dynamic PSU or a good amp. And not adding to the amp evil loads and random noises and as pure as it can be for a price some can afford not just the bling hunters.
Ok some will hear a better sound some will hear no change but I am now 64yrs old I can still hear up to 18KHz my brother can't hear past 7KHz he also can't detect image. Oh the point is we are all not clones based on a perfect human, some of us are Martians.
Test your self try "One Night In Paris" from 10cc
see if when the bike and bell go by your head and behind you, and with just 2 speakers in front of you can you hear it ?? (phase guys phase) A well set up system will bring Paris to life in you home but watch out for the cars please.
tuga
Legal Alien
This cable for ESL white paper may interest you:
http://sanderssoundsystems.com/technical-white-papers/54-cables-white-paper
Jim Audiomisc
pfm Member
Alas, calling something a 'white paper' and including some graphs doesn't ensure the content makes sense or correctly describes the *relevant* reality in such a way to let the reader apply it to their own situation.
The "best" cable is, primarily, the shortest.
Beyond that its a matter of ensuring it can carry the current and have negligible total series impedance, etc. The decision on "negligible" depends on the context. e.g. if your amp already has an output inductor that may affect judgement on the level of concern about added cable series inductance, etc.But none of the above requires much in the way of fancy constructions, rare and novel materials, etc. Just the basics of electronics and physics.
Personally, I use some of the thick multistranded cable I bought years ago from Maplin to feed my ESLs (988s and 2805s). I've forgotten what the part number was, but thick multistranded. Probably one of the types I used for the comparisions on
http://www.audiomisc.co.uk/HFN/Cables3/TakeTheLead.html
For ESLs low series inductance may be handy. But note that physics requires that any construction which reduces the inductance/metre means an increase in capacitance per metre. In our Universe this is because there is a limit related to the speed of light that requires this. So when a maker boasts of 'low inductance' expect 'high capacitance' even if they oddly omit to mention this.
"Inductance in a speaker cable is largely determined by the area between the conductors. Most speaker cables have conductors that run side by side ("twin-lead"). These conductors are separated by a small distance, so have moderate inductance. Therefore, twin-lead cables do not have the low inductance desired for the best performance when driving ESLs."
This statement is not quite right.
"
"Capacitance is a function of how close the conductors are to each other. So to keep the capacitance low, the conductors must be widely separated. Note that this is just the opposite of what we need for low inductance."
He is writing here about common mode inductance, the magnetic coupling of the conductors the higher the better.
"Many cable manufacturers deliberately add a lot of capacitance to their cables. For example, you will find a box at the end of MIT cables, which contains capacitors. Alpha Core (Goertz) cables are made as a sandwich with two ribbon conductors very close together, which produces high capacitance and often, amplifier instability. Woven wires are close together so have high capacitance. These types of high-capacitance cables are best avoided when operating ESLs."
So many cable designs get this wrong LOW CAPACITANCE GOOD
" Resistance is the tendency for the wire in a cable to oppose the flow of current. Most cables are designed to have low resistance so that they don't significantly reduce the damping factor of the amplifier.
Some manufacturers deliberately use high resistance cables to alter the sound of the magnetic speakers by both interacting with the speaker's crossover and reducing the damping factor. When the damping factor is reduced, the amplifier cannot keep the woofer under good, tight control. The result is that the bass becomes "loose" and poorly controlled."
Spot ON
This is well worth the read.
http://sanderssoundsystems.com/technical-white-papers/54-cables-white-paper
This statement is not quite right.
"
"Capacitance is a function of how close the conductors are to each other. So to keep the capacitance low, the conductors must be widely separated. Note that this is just the opposite of what we need for low inductance."
He is writing here about common mode inductance, the magnetic coupling of the conductors the higher the better.
"Many cable manufacturers deliberately add a lot of capacitance to their cables. For example, you will find a box at the end of MIT cables, which contains capacitors. Alpha Core (Goertz) cables are made as a sandwich with two ribbon conductors very close together, which produces high capacitance and often, amplifier instability. Woven wires are close together so have high capacitance. These types of high-capacitance cables are best avoided when operating ESLs."
So many cable designs get this wrong LOW CAPACITANCE GOOD
" Resistance is the tendency for the wire in a cable to oppose the flow of current. Most cables are designed to have low resistance so that they don't significantly reduce the damping factor of the amplifier.
Some manufacturers deliberately use high resistance cables to alter the sound of the magnetic speakers by both interacting with the speaker's crossover and reducing the damping factor. When the damping factor is reduced, the amplifier cannot keep the woofer under good, tight control. The result is that the bass becomes "loose" and poorly controlled."
Spot ON
This is well worth the read.
http://sanderssoundsystems.com/technical-white-papers/54-cables-white-paper
Jim Audiomisc
pfm Member
I'd take a different tack. Having a high cable series inductance increases the chance/degree of HF effects when given a capacitative end-load. It *may* help avoid problems with an amp that isn't unconditionally stable, but can mean a change in frequency response.
Having a *low* cable series inductance reduces any such change in HF response, but can expose the *amplifier* to instability or other effects. However this is an *amplifier* problem.
Note the unavoidable point that the the minimum value of the capacitance/metre and inductance/metre product is fixed in our Universe. So making one ultra-low generally means boosting the other. Your way out is a shorter cable.
Thus if you want to consider the relative merits of the cables you may need to know the output impedance and stability performance of your amplifier. One of the key snags of the 'white paper' is that it presents pretty results whilst glossing over these very real details - which vary from case to case.
Werner
pfm Member
The general audience does not know the difference between a 'white paper' and a 'paper'. A fact readily exploited by the, er, exploiters.
Thank you, thank you, thank you! Finally a speaker cable that costs more than the rest of my audio system. Been looking for like forever.
re "for electrostats", is there something I am missing...other than the MIT's?
I'd take a different tack. Having a high cable series inductance increases the chance/degree of HF effects when given a capacitative end-load. It *may* help avoid problems with an amp that isn't unconditionally stable, but can mean a change in frequency response.
Having a *low* cable series inductance reduces any such change in HF response, but can expose the *amplifier* to instability or other effects. However this is an *amplifier* problem.
Note the unavoidable point that the the minimum value of the capacitance/metre and inductance/metre product is fixed in our Universe. So making one ultra-low generally means boosting the other. Your way out is a shorter cable.
Thus if you want to consider the relative merits of the cables you may need to know the output impedance and stability performance of your amplifier. One of the key snags of the 'white paper' is that it presents pretty results whilst glossing over these very real details - which vary from case to case.
Quite sure my amps will not be a problem. From the QED Supremus specs, it appears that they have done well in minimizing both Capacitance and Inductance, part of my reason for being interested. To your point re length, I can actually get away with 1m which should help.
Arkless Electronics
Trade: Amp design and repairs.
Worse than that the "general audience" not only doesn't seem to know the difference between science/the laws of physics and fairy dust/unicorn farts but actually doesn't want to know. If a snake oil salesman tries to con them with pseudo scientific bollocks they're like "do tell me more!" but if an engineer/scientist tries to show that it is impossible for the foo to work, as it would have to break the laws of physics, then it's "fingers in ears and go LA LA LA very loudly" time
hi fi's like a religion to the "general audience" and anything can work if you "have faith"... Peter Belt sticky plastic triangles, cable lifters, foo mains cables, magic fuses etc etc. Science is seen as the nasty non believing atheist trying to persuade them there is no such thing as god.... and they really don't like it! The irony of it being science/engineering that designed and built the equipment in the first place seems lost on them.... Maybe once an amp leaves the factory it ceases to be a piece of engineering and becomes something with a soul that can tune into the natural vibes (cool man) from oak cones placed underneath it...
I'll get my coat
Craig B
Re:trophile
If only they'd print them on softer paper; as least then they'd have a use in the guest bathroom.
Thighsofsteel
pfm Member
'We have always believed that the most sophisticated sound receiving device of
all time is the truly incredible human ear, and we both acknowledge and are
challenged by how this wonderful instrument can detect the most minute of
sonic differences that we currently struggle to measure.'
Condenser Microsphones from the 1940s could out perform the Human ear. The reason we struggle to measure the 'minute sonic' differences is they DO NOT exist.
What a very poor paper that is.
all time is the truly incredible human ear, and we both acknowledge and are
challenged by how this wonderful instrument can detect the most minute of
sonic differences that we currently struggle to measure.'
Condenser Microsphones from the 1940s could out perform the Human ear. The reason we struggle to measure the 'minute sonic' differences is they DO NOT exist.
What a very poor paper that is.
Jim Audiomisc
pfm Member
The two key things a user would need to know about their amp in this context are:
1) Is it unconditionally stable? If it is established that it *is*, then you don't need to worry about likely amounts of speaker cable capacitance. So need not be concerned about cable capacitance values. You can then focus on getting low series resistance and inductance.
2) What is its output impedance behaviour? In particular does it have a high output impedance, and/or one that is inductive at HF? e.g. does it have an output inductor?
'High' here is relative to the likely levels of cable series resistance and inductance.
Valve amps, particularly low-feedback designs, tend to have much higher output impedances than solid-state designs with a fair amount of feedback. In the end this comes down to a matter of the specific details of a case. But, as per before, the 'best' cable tends to be the shortest.
You should also know something about your speaker's impedance properties. If you are using a speaker that has a high input impedance, then that will reduce the effects of cable series resistance and inductance accordingly.
Note that maker's specs and measurements tend to choose to use lengths like 5 or 10 metres of cable. This means the effects of the cable are much larger than if you can use cable runs of just a couple of metres or less.
IIRC the 'white paper' used 10 metre runs. So - roughly - if you can use just 1 metre you can expect about ten times less of the 'effects' they whitter on about.
The problem, of course, is that often people don't know the relevant details for the amp and speakers they are using. So can't easily assess the above. But the general rule remains that the shorter the cable, the better.
Arkless Electronics
Trade: Amp design and repairs.
I'm fully in agreement with the keep it short and thick bit, which was my own advice earlier. Now if I may put my pedants hat on... feedback amps tend to look inductive at their outputs anyway and usually to a much greater degree than that added by the output inductor. The inductor will usually have a damping resistor across it and this can be much lower than (should be in fact) the standard 10R. 1R usually works fine and is not rare.
Only the cable resistance effects the full frequency range. Capacitance and inductance obviously have an increasing influence as frequency rises but a typical moving coil speaker will have rising impedance at HF due to the inductance of the tweeter voice coil, and so at frequencies where the inductance and capacitance begin to have a tiny effect the load is much easier anyway and far less likely to be influenced by these parameters (I'm aware that there are a few ifs and buts and gotchas to this hence my italics for typical. I'm generalising of course).
Whilst the laws of physics dictate that "these effects" do exist, IMO the degree to which they actually effect things is so small with typical amps, speakers and reasonably short, thick cable runs as to be completely negligible. The foo cables are addressing a non existent problem.