Hi perceval, it would have been helpful to have seen the impedance of that wiring scheme. Though if the drivers all shared a common volume there would still be series drivers sharing a common volume.
X's analysis with Akabak does show differences too so there is a rather pronounced difference when the drivers aren't matched completely. Proper damping helps (like I tried to do) to limit these differences.
Even though the resulting FR does not show any true differences in a sim, the parallel wired drivers act more alike and each have about the same movement.
More power would exaggerate these differences and that's probably where the parallel wiring scheme wins.
Series connected drivers seem to be more susceptible to differences than parallel wired drivers.
If every driver would act as an ideal one, no differences would show up.
X's analysis with Akabak does show differences too so there is a rather pronounced difference when the drivers aren't matched completely. Proper damping helps (like I tried to do) to limit these differences.
Even though the resulting FR does not show any true differences in a sim, the parallel wired drivers act more alike and each have about the same movement.
More power would exaggerate these differences and that's probably where the parallel wiring scheme wins.
Series connected drivers seem to be more susceptible to differences than parallel wired drivers.
If every driver would act as an ideal one, no differences would show up.
Here's the wiring scheme I'm thinking of implementing:
The U shaped wires between the rows of drivers stand for thicker strands of wire running along the length through the enclosure.
They connect like this: from binding post to the first 5 positive, the other side connects the first 5 negative and next 5 positive and so on until the last set of negatives routes back to the negative binding post.
I'm still searching for the specific wire I want to use, both the thicker runs and the short wires that connect to each driver. I'd like to find affordable wire with Teflon coat and not to many strands, yet still flexible. Maybe silver coated even. Is there any good quality 22 AWG hookup wire? Hard to find all specs I'd like. Maybe something like this? Teflon coated silver plated copper, 7 strands to make up 22 AWG
Where to buy and what to get in Europe...
The U shaped wires between the rows of drivers stand for thicker strands of wire running along the length through the enclosure.
They connect like this: from binding post to the first 5 positive, the other side connects the first 5 negative and next 5 positive and so on until the last set of negatives routes back to the negative binding post.
I'm still searching for the specific wire I want to use, both the thicker runs and the short wires that connect to each driver. I'd like to find affordable wire with Teflon coat and not to many strands, yet still flexible. Maybe silver coated even. Is there any good quality 22 AWG hookup wire? Hard to find all specs I'd like. Maybe something like this? Teflon coated silver plated copper, 7 strands to make up 22 AWG
Where to buy and what to get in Europe...
Crimp and solder. Due to lack of professional crimping tools I will crimp and use the solder to make it air tight. Shrink wrap to finish.
I did a speaker wire test quite a while ago. The more solid the wire, the better the high frequencies behaved. Silver plated wire has a reputation of being better at high frequencies, this usually is combined with Teflon insulation.
I did not test that combination at that time, but I'm interested to "see" if there are differences. I'll use slightly more wire with the new wiring scheme.
Teflon will be more temp resistant than a PVC coated wire. Do I need it? Main feature for me is corrosion resistance and limited number of strands. I chose a 7 strand wire for some flexibility. Solid core would be too stiff, making it harder to get the lid back on with a 25 driver enclosure.
Before I actually did that wire test I did not believe in audible differences between wires. My test was questioned by others but I 'believe" there is a difference because I was able to measure it. I ran multiple tests to make sure and the results were the same each time. The more solid the cores were, the better the high frequencies performed.
This test was done with FIR correction included. FIR correction could not save my "lamp cord" and make it perform like the solid core and stiff core wire.
The "lamp cord" I used was a pure OFC wire by the way.
Solid core wasn't practical, the wire with stiff, less cores performed the same as the solid core in measurements and is what I use as speaker wire.
My internal wire right now is still of the multi-strand OFC (flexible) kind. I will resurrect that problem. I can't tell in advance what the silver plated wire does. No experience yet. Only testaments on this forum that there are indeed differences.
I'm still up in the air though on the need for silver plated copper. The test I did with litze type wire in small vs thicker cores were all with pure copper.
So maybe I don't want to add another unknown variable.
I've been eyeing this one:
6823 BK005 | Alpha Wire Black, 30m MPPE Hook Up Wire, 0.35 mm² CSA , 300 V 22 AWG | Alpha Wire
The electrical parameters are just about equal to the silver plated Teflon coated wire. The price is about the same too, so that's no decision maker.
So maybe I don't want to add another unknown variable.
I've been eyeing this one:
6823 BK005 | Alpha Wire Black, 30m MPPE Hook Up Wire, 0.35 mm² CSA , 300 V 22 AWG | Alpha Wire
The electrical parameters are just about equal to the silver plated Teflon coated wire. The price is about the same too, so that's no decision maker.
It is interesting that you say solid core wire is better than multi-strands for high frequencies, particularly because you claim this on objective tests rather than subjective terms.
I am not sure what you mean by 'behave'. But when it comes to HF attenuation due to skin effect, multi-strands will always perform better than solid core, even though in a proper utilization using both type of wire this happens in the MHz region. But I believe you already know that. I am curious to know about this 'HF behavior' you found out on your tests, which is not DSP-able?
Fun trivia: a single TC9 has around 3.5 meters of most likely non-OFC
I am not sure what you mean by 'behave'. But when it comes to HF attenuation due to skin effect, multi-strands will always perform better than solid core, even though in a proper utilization using both type of wire this happens in the MHz region. But I believe you already know that. I am curious to know about this 'HF behavior' you found out on your tests, which is not DSP-able?
Fun trivia: a single TC9 has around 3.5 meters of most likely non-OFC
Sorry, for the wrong facts. Its actually a little more than 6 meters of 0.150mm nominal dia copper wire in the voice coil of the TC9
It's documented in this thread with measurements. There is a difference noticeable in high frequencies. Un-EQ-ed the solid core wire had a slightly elevated high frequency response compared to the OFC litze type wire.
When looking into detailed group delay response graphs over the top end the OFC wire showed more dips than the solid copper wire. I measured more than once to see if I was just fooling myself. FIR filters are able to fix the frequency response, but did not fix the group delay dips I was seeing in slightly longer (5 ms) windows. The frequency dependent window it too short to do anything there. This is happening over time, be it, a very short time.
The start of that wire test here:
http://www.diyaudio.com/forums/full-range/242171-making-two-towers-25-driver-full-range-line-array-118.html#post4352467
Going back and forth between wires confirmed a difference between the two.
Digging deeper there was a group delay difference as well:
http://www.diyaudio.com/forums/full-range/242171-making-two-towers-25-driver-full-range-line-array-125.html#post4361235
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Looks serious interesting wesayso and waiting anxiously if it objective measure/behave/sound any better.
Pretty sure that was me
I'm a little confused about the specs on that cable as it says 7 strands 0.25mm. The Canare Speaker cable I have used in the past is 0.25mm strands and the number of strands depends on the gauge of the cable. I actually separated some strands to use for point to point wiring of an SMD chip.
Seems just like thin copper multi-strand cable to me
22 AWG will be quite high in resistance and in large enough quantities will have a noticeable insertion loss.
You could strip some Cat 5 cable and use a twisted pair together, two strands of solid core copper both 24 AWG each. It is very flexible as the insulation is thin.
I have bought some silver plated teflon wire recently in a few different gauges directly from China as it was so cheap, it's quite nice but I can't see myself using it as speaker cable.
I'm a little confused about the specs on that cable as it says 7 strands 0.25mm. The Canare Speaker cable I have used in the past is 0.25mm strands and the number of strands depends on the gauge of the cable. I actually separated some strands to use for point to point wiring of an SMD chip.
Seems just like thin copper multi-strand cable to me
Compare it to wire with 19 strands being 0,13 mm and the 7 strands will be way stiffer, but still more flexible than single core. As said, the speaker wire I ended up with had less cores than the multi strand OFC wire. The multi strand being really multi strand in comparison. Very flexible, too bad it measured worse. Technically they both are multi strand, but with a measurable difference. Solid single core copper wire and the lower count multi strand wire measured pretty much identical. The more flexible OFC wire was worse in comparison. The AWG numbers were the same. One core of the speaker wire I ended up with (it's probably close to 0.25 mm cores, 14 AWG so still plenty of cores) could punch a hole in your finger like a needle, the OFC wire could never do that with it's soft bendable strands. That should illustrate the difference somewhat I hope.
The maximum lengths of the 22 AWG wire will be quite short, like about 25 to 30 cm. The U shape in the wiring scheme will use something more substantial, like 14 AWG wire. (I use these sizes in the current wiring, but as said, it's still the flexible multi stranded OFC wire that measured worse as speaker wire.
The thing I like about the wire I linked is it's low inductance of 0.05 μH/ft. It's resistance of 0.015 Ohm/ft. isn't too bad for these short distances.
Compare it to the list of wires as tested by Nelson Pass.
I bet the one I called multi stranded OFC would probably measure more like the 24 AWG zip cord did. I have way less info on that wire, except for the bragging about the 99.99% OFC in the description. (yes, that made me buy it) Wire is wire right? at least that's what I thought. I didn't expect to find differences, but seeing it in Halair's measurements made me curious enough to check for myself.
It looks like it is about balance between the amp, the wire and the speaker. At least that's what I get out of the Pass labs story.
FIR filtering would correct the FR differences so I'm not worried about that. Do wires really sound different? You bet for most people that don't use EQ. But I didn't expect to see phase differences happening over time (when both are corrected to the same FR with FIR).
I have some samples of CAT5, it really isn't as flexible as the 7 strand wire. I don't think I need to double up on the short leads to the speaker though.
You may have been thinking I'd use all 24 AWG wire? Due to having more wire with this connection scheme I want a lower resistance than that.
The U shaped wires between the rows of drivers stand for thicker strands of wire running along the length through the enclosure.
Why not? Where do you use it or what for? I'm still up in the air about it's merits but have seen many people rave about them and others preferring copper. Sadly those opinions have no value to me. I've seen the results of the speaker listening tests X did. Some horrible ones (to my ears at least) still got a lot of votes. It's much harder to find real clues and as said, it could be a combination of all three, speaker, amp and wire.
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Tempting... I'd skip any series connection if I could, 25 amps being even better?
I'm hoping Owen will show his measurements. I'm still holding back a little to see what that may bring. Nothing ordered yet.
If people wonder why I would consider this surgery, don't forget, I'm the fool that uses impedance correction in an active speaker.
Why? Curiosity and looking for answers. The Pass Labs story might explain why I didn't like the upper impedance correction, all wires seem to follow the impedance raise as seen in the array impedance, the ones with lower impedance (like Audio Source Hi. Def.) would basically mimic the speaker impedance curve but at a lower level. If that means anything...
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Strangely, wesayso's first teflon wire of interest from RS is three times the price on the Australian RS site, but the second wire is of a comparable price.
I have never done as much testing on cables as wesayso has, but as I wind transformers occasionally, I have always been happy 'playing' with various configurations of PE2 (solid core) winding wire always assuming that the PE2 coating will keep the wire form oxidizing for many, many years. Tried both single core and litz type configurations. Agree with wesayso that it can get a bit inflexible.
I have never done as much testing on cables as wesayso has, but as I wind transformers occasionally, I have always been happy 'playing' with various configurations of PE2 (solid core) winding wire always assuming that the PE2 coating will keep the wire form oxidizing for many, many years. Tried both single core and litz type configurations. Agree with wesayso that it can get a bit inflexible.
Now if only I could make sense of it, maybe then I could make an educated guess
.Both wires I linked were the few that actually show a bit more actual data in the datasheet. Most wires datasheets only show their size.
I have no clue what to look for as far as amp/wires/speaker goes. All I know is there should be some balance there.
For instance: silver plated copper wire is often referred to as bright. Without knowing what it really does it's kind of hard to guess.
With my speaker wire tests I did see difference in SPL level at the top end. As said, those differences would vanish with DSP, except when the phase gets disrupted outside of the FDW I use. And why would that happen?
Most phase related deviations over time were directly related to reflections/diffraction. What is it that a wire could do different to show similar behavior. In other words, what combination of resistance, inductance and capacitance would be the right choice.
As hinted by samuelj some of these numbers should only influence an area way outside the pass band of the speakers. Yet it does seem to influence the area of interest, like the Polk wire mentioned in the paper by Mr. Pass.
I am by no means an expert on electrical properties. The graph shown with the difference in group delay of the wires I tested is not a normal view you'd see. It's like looking at it under a microscope:
Normally, with usual time-scale it would look like this:
That's the same wire on both plots. Though if using another wire can get this under that same microscopic view:
It results in a similar difference as the whole series/parallel debate. My gut tells me to go for the one that measures smoothest. Without asking the question: can you hear that?
So far that route has given me quite good and pleasing results. Half the time I read about people that say: we can't measure what we hear. And when we do get differences turn up in measurements others are likely to say: but can we hear it?
I think we probably will have difficulty hearing some of the differences we measure, but every little detail that makes the overall behavior smoother is going to help to get a good or better end result. At least that's my point of view. Which means I can't close my eyes for these differences.
The fact that we measure with one microphone (that has no brain attached to it) and hear with two ears (that has that strange processor attached called our brain) doesn't exactly help.
It still puzzles me how it all can work inside our head. I often wonder if I were to invite singing identical twins. Place each of them at a 30 degree angle, one left and one right, as seen from my listening position and make them sing simultaneously, would I hear only one voice in the phantom center?
The ability of our brain to group and sort sound fragments is nothing short of dazzling. One of the important features of that sorting and grouping is timing.
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The Pass Labs article is good it confirms most of what I think about cables. Keep them as short as possible to reduce their effects and if they need to be longer make them thicker. Any fancy cable has been manufactured to be different in some way and usually that means that it performs worse than a standard cable in some way. It may help some systems but will be worse in most.
Linkwitz gives some information about cable gauge and length and it's effect on impedance.
FAQ
That makes sense to me and is one of the reasons I prefer to use thicker cable overall if possible.
Phillip Newell has a section on cables in his book on Studio Design. A good read if you have it and makes a lot of sense to me. He recommends very thick automotive style power cable 4 gauge. I have used some as speaker leads in the past, works well but is very bulky
I cannot explain your phase and group delay measurements of different wires, it is possible that a combination of wires makes your amp unstable in some way like in the Pass Labs article. I would need to do a lot more comparisons in different circumstances to draw any conclusions from it in regards to solid vs stranded but I totally understand why you would pick the one that measures the best in your circumstances doesn't make sense to do otherwise
I used 16AWG multi-stranded copper cables, 29x0.25mm with a PVC jacket, it was cheap high quality and thick enough by my calculations.
I suppose the total resistance is what matters and you could use heavier gauge cable in one area to make up for lighter in another.You may have been thinking I'd use all 24 AWG wire? Due to having more wire with this connection scheme I want a lower resistance than that.
I bought the silver plated wire to use in amplifiers as signal cable and power cables between boards. You can see some of it in my First One pictures and LKS DAC. The teflon insulation is very slippery and was quite difficult to make twisted leads out of, was a real pain actually!
I don't have enough to use as speaker cable and I didn't buy it in a gauge that I would like to use for speakers.
I don't find it any different than copper in the quantities I use but then I didn't expect to either.
Expectation bias can be a real problem and if you expect the silver wire to be bright because that's what everyone says then you may well hear it, but was it really?
Pick whatever makes the most sense to you, you only need to please yourself after all
I cannot explain your phase and group delay measurements of different wires, it is possible that a combination of wires makes your amp unstable in some way like in the Pass Labs article. I would need to do a lot more comparisons in different circumstances to draw any conclusions from it in regards to solid vs stranded but I totally understand why you would pick the one that measures the best in your circumstances doesn't make sense to do otherwise
I tested 4 different wires I had on hand. I started with very old speaker wire which was very expensive when I bought it many years ago. This was the worst performer. Upon closer inspection the copper had corroded inside the jacket.
Much to my surprise (and disappointment) the cable I used inside my enclosure as main wire didn't do much better. This was the very flexible OFC wire, consisting of many fine strands.
Next up was that same wire, only doubled up this time: no improvement.
I decided to try single core house-hold wiring as I had it on hand. That's when I saw a clear improvement in output and phase on the top end.
I went back into the garage to see what else I could find. I had a box of wire consisting of multi strand with 0.25mm cores and tried that. Basically giving me the same results as the solid core, it's what stayed. It's 14 AWG.
So I definitely blame the OFC wire as performing less than stellar, whatever the reason.
I don't think resistance is the only reason, all three parameters are going to determine the final outcome. That part is dependent on the type of load and amplifier. I agree on using wire with low enough resistance, which I had used as a guide line to buy my wire.
If I had not seen Halair's measurements I wouldn't have had any clue to check this at all. If he had not used two different type of wires on his left and right channel I wouldn't have seen it.
You tell me (not directed to fluid specifically
) what the perfect wire would be. There's so much variation as seen in the table in the Pass paper, it's too hard (for me) to predict anything useful. I bought the silver plated wire to use in amplifiers as signal cable and power cables between boards. You can see some of it in my First One pictures and LKS DAC. The teflon insulation is very slippery and was quite difficult to make twisted leads out of, was a real pain actually!
I don't have enough to use as speaker cable and I didn't buy it in a gauge that I would like to use for speakers.
I don't find it any different than copper in the quantities I use but then I didn't expect to either.
Expectation bias can be a real problem and if you expect the silver wire to be bright because that's what everyone says then you may well hear it, but was it really?
Pick whatever makes the most sense to you, you only need to please yourself after all
Well, based on my tests I'd call my current speaker wires and the house-hold single core brighter than the oxidized type of wire I had before
.That's why I used FIR filters as the referee to make the balance the same.
The only thing I wonder about is if there really is a measurable difference there for silver plated wire in a Teflon coat.
Between both wires I linked to, there's no discernible difference in the parameters. Capacitance is missing though.
Most other wires in that list at RS don't show any parameters at all. It isn't just a length issue what changes these parameters, the actual construction of the wire can (and will) make a difference too. So the Linkwitz piece did not help me much at all.
It's missing the information I want to see. I already know I want to keep resistance down, but what about the other wire parameters...
A tube amp may require a different approach than a solid state amp, etc.