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This is my first experience with high efficency, single driver, back-loaded loudspeakers so bear with me.
I noticed that my newly-acquired Royal Device Laura speakers have two sets of speaker terminals on the back (one set on top, too). I see that the manufacturer recommends the use of his own bi-wire cables (see review). I ain't gonna do that, however. These babies might get a double run of Home Depot style speaker cable.
But then, why would a single-driver benefit from a double run of cable?
Follow Ups:
Bi-wiring is running two pairs of wires from each channel's power amp to its speaker, connecting them to the mid/tweeter and the woofer binding post pairs. You cannot bi-wire a single driver speaker.
I think Richard Vandersteen figured out how bi-wiring works, and why some people get great results and others get no results. It has to do with the Hall effect, i.e. the voltage difference across a conductor and the resultant magnetic field transverse to the direction of the current. Richard guessed that the large Hall effect field from the large current going to the woofer, which he could measure, interfered with the very small high-frequency current. So running two pairs of wires, one to the mid/highs, and the other to the lows, with a crossover designed for those connections *could* make a big difference, provided that the two pairs of wires were kept an inch or more apart for most of their run.
That separation requirement, to keep the mids/highs wire pair physically removed from the Hall effect magnetic field generated by the low-frequency wire pair, is what is often missing. That explains why some people get great results (with separated wire pairs) and others get no results (with both wire pairs in one cable.)
His description of how they investigated this and what they figured out is on his FAQ page.
WW
"A man need merely light the filaments of his receiving set and the world's greatest artists will perform for him." Alfred N. Goldsmith, RCA, 1922
I'll have to try bi-wiring per the Vandersteen method sometime to find out if it makes any diff with my speakers.
I should clarify that my speakers are sometimes called "augmented single-driver" speakers. But, because there is no crossover on the main driver (which extends to over 9000 hz), and because the "tweeter" seems more like a supertweeter to me, I call them "single-driver". There are two sets of binding posts on the rear for bi-wiring purposes.
Doubling the identical cable halves its impedance, and almost all speaker cables are much higher impedance than the speaker, so getting the impedance down is good. Remember, this is AC, not DC, and impedance is not the same as DC resistance, so don't take out the multimeter to prove me wrong, those are DC measurements. Doubling up cables to a single driver can indeed improve sound.
> "Doubling the identical cable halves its impedance, and almost all speaker cables are much higher impedance than the speaker,"
I can only assume that you came to that conclusion based on cables being classified as 75 ohm, 300 ohm and so forth. That classification refers to their transmission line impedance, not their measured series impedance. Transmission line impedance is a factor with radio wave frequencies, but not audio frequencies. If a speaker cable actually had a 75 ohm series impedance the capacitance and inductance would be so high that the speaker would barely work at all. Well designed and constructed speaker cables of commonly used length have low enough capacitance and inductance that those factors can be ignored, with the cable DCR being the only significant factor. Common zip cord falls into that category. Oddly enough some very high priced exotic cables do have excessive capacitance and/or inductance, which results in high frequency signal losses. Manufacturers of those cables call them 'audiophile grade'. I call them 'defective'.
Big mistake to ignore transmission line theory when working with audio cables. Though the distances are short and frequencies relatively low the signal is wideband AC and utilizing transmission line theory yields audible and measureable improvements.
> "Big mistake to ignore transmission line theory when working with audio cables. Though the distances are short and frequencies relatively low the signal is wideband AC and utilizing transmission line theory yields audible and measureable improvements."
That's buying into the nonsense spewed by the 'high end' cable industry. What you must remember about them is that they want your money, as much of it as possible, and will say anything to get it, including downright lies.
In any event, as to your original statement, that speaker cables are much higher impedance than speakers, it's simply not true.
You obviously have not done the work on cables deeply enough, Bill, to really know what matters in an audio cable. Having worked in defense in both wideband analog as well as digital signal transmission, I assure you, I've done the work and I am not buying into the total nonsense that nearly every audio cable manufacturer spews.
Characteristic impedance is relevant to a certain degree, since series and parallel impedance values are relevant and characteristic impedance is derived from the series and parallel values, which themselves are calculated from the 4 basic cable electrical parameters.
Not worth a debate about theory that you have not spent years working on and which will bore others, but it is obvious you have not scratched the skin of the onion, though it is just as obvious you'll not be admitting that.
I have worked in defense industries, have patents with RF/Microwave systems, know exactly what you're talking about and none of that matters.
You're picking a fight, rudely, with someone who has contributed a tremendous amount to the speaker/audio community through his articles, forums, kits, plans and posts hiding behind a pseudonym.
I think you owe Bill an apology.
Scott Hinson
speakerscott.tumblr.com
www.etsy.com/shop/SpeakerScott
There comes a time to agree to disagree.
I've followed the scientific method, have the equipment to measure the results when one change at a time is made, and have demonstrated, in waveform analysis, measurements, and with listening panels, that transmission line theory applies, to a surprising degree, to audio cable design. Disagree as you wish, agree as you wish. But I'll submit that I have gone to great lengths in effort and expense to really find out, rather than offer up an opinion without extensive testing. My position, before testing, was dubious, but I was curious. A scientist wants to find the truth rather to adhere to an opinion of what might be.
I have not worked in defense in both wideband analog as well as digital signal transmission. That's not my field of expertise. My field of expertise is loudspeaker design. Where speaker cables are concerned my knowledge base is certainly adequate, sufficient enough to know that speaker cables which are not defective do not have higher impedance than speakers, or for that matter anything even remotely approaching the impedance of speakers. IMHO anyone making that suggestion should refrain from making comment on a loudspeaker forum, and stick to a field where they do have the requisite knowledge base to offer expert commentary that actually comes from an expert.
Oh, touchy when someone knows more and corrects your correction, huh? Sorry, I'm new here and did not know the etiquette of who patrols the forum space and who not to correct even if they are wrong.
I don't care what forum the questions was in, it was a cable question, one of my fields of expertise. I have experience with audio cables using high efficiency horn designs all the way down to 80db power suckers. As such, his question was right in "my wheelhouse" as they say, right in my field of expertise.
Not so... Snake oil.
> I see that the manufacturer recommends the use of his own bi-wire cables <
That alone should get your radar bleeping....
And "bleep" it did!
That said, I think the manufacturer genuinely believes in the "wholistic system" approach. Amp, cables, and speakers together create a "tune", or a specific sound. It sounds like a clever marketing scheme (and maybe it is), but strategies like that sometimes lead to excellent results, I'm sure. I'll never know for sure because I am not planning on purchasing the "matching" amps and cables from Royal Device.
Since even a two way gets absolutely no benefit from bi-wiring a single driver would get half of nothing, which is still nothing. The manufacturer selling you the cable, however, gets twice what he'd get compared to single conductors, so he benefits greatly.
Threads like this make the lack of smileys at this site painfully obvious. I humbly request the adoption of software appropriate for the 21st century.
I'd have used a smiley there as well, had I the option.
Along with ROTFL... we have always had these:
:) ;) :P Respectively... haha, just kidding and nyahhh.
And yet, some people say they can hear the diff.
In Reply to: RE: Why would single driver speakers benefit from bi-wiring? posted by Bill Fitzmaurice on July 18, 2014 at 16:29:12:"And yet, some people say they can hear the diff."
I imagine these might well be the same people who hear a huge dramatic difference between their new $50,000.00 per 8' pair speaker cables and the sorry crud $30,000.00/pair 8" cables they were previously using.
Edits: 08/05/14 08/05/14
Opus 33 1/3
> And yet, some people say they can hear the diff.
If there was no such thing as placebo effect there would be no name for it.
I happen to have a lot of Radio Shack speaker wire lying around, I'll compare double-wired to single-wired. I'm hoping those darn placebos won't get me.
.I'll compare double-wired to single-wired. I'm hoping those darn placebos won't get me.
If you do the only way to be sure of what's actually happening is to measure the results and/or to conduct a double blind listening test. If your eyes and your expectations aren't totally isolated from the experiment then your ears will only tell you what you expect that they will.
that a human mind and ear is so pathetic poor in performance that a DBT and measurements are the ONLY way to asses a tweak.
Why should I bother myself to listen to music under unnatural conditions and in an unnatural environment? When I'm at home I must trust hearing, to some degree at least.
Edits: 07/19/14 07/19/14
Why bother ,,,no effect will be heard...
One post for midbass
One post for xover to tweeter and then tweeter is connected to the binding set on the top of speaker.
Tweeter has a 24 db xover between it and the amp input.
The topside speaker terminals are internally connected to the primary speaker terminals, as far as I know.I would have thought to simply connect the bi-wire pair to the double terminals on back, per manufacturer's suggestion. The manufacturer, rightly or wrongly, thinks that bi-wiring his speakers help them to sound their best.
Review quote: "Royal Device specifies the exclusive use of it's proprietary bi-wire speaker cable with all of it's models to ensure best performance."
The Laura is touted as being a crossover-less speaker and is (supertweeter or no) essentially a "single-driver" speaker. The supertweeter contributes very little high frequency info in this design and one wouldn't think that bi-wiring would do much of anything, but the proof is in the listening.
Edits: 07/18/14 07/18/14 07/18/14 07/18/14 07/20/14 07/20/14
I've probably heard the exact same unit you have, from none other than Mr Bankert himself. Spent a good deal of time with him and his offerings over many years.
Yeah, but disconnecting the supertweeter entirely barely changes the sound. It adds a slight haze of sparkle and sheen. The supertweeter uses a 24db high pass filter at 9 khz, woofer extension is 10,000 hz. I really wonder how much difference a separate cable will make. I'm using jumper cables now but, as I've said, I am going to try bi-wired.You say that you have heard this very unit? Was Sonist Audio in Idaho at that time? Maybe you can advise me, because I noticed that the inner folds of the speaker cabinet are lined with sheets of 3/4" grey acoustic foam and I need to replace the foam sheets in one speaker. Can you recommend a certain type of replacement foam?
Edits: 07/21/14 07/21/14 07/21/14 07/21/14 07/21/14 07/21/14 07/21/14
Royal is an italian company as I recall. I have no idea as to the source of the foam you mention.
Parts Express sells foam in many thicknesses, I hope it works likes the original stuff.
> Review quote: "Royal Device specifies the exclusive use of it's proprietary bi-wire speaker cable with all of it's models to ensure best performance."
Royal Device specifies the exclusive use of its proprietary bi-wire speaker cable with all of its models to ensure their maximum profit margin. :)
enter a new dimension in 2017 when the Second Sun arrives, hits ours and creates a black hole!edit: BTW, there appears to be one flavor of the Laura that uses three drivers found on their website here . Maybe they share the same cabinet.
Edits: 07/18/14
You have to wonder why they're making speakers if the world is ending in a couple of years. On the other hand, they could actually be right claiming to make the best speakers you'll ever own.
I just hooked them up to a pair of ASL Wave 8SE moonoblocks. They really sound smooth and vivid playing acoustic stuff in my 17' X 13' room, from about 10 feet away. The soundstage is both wider and higher than the speakers but imaging does not seem "etched" - the sonic picture seems romantic or distant. Definitely, this is not an "in your face" presentation. Small musical groups, acoustic music of all kinds, some orchestral music will be well served. These speakers also sound very "coherent", as you'd hope for in a single driver speaker. Bass seems clean and fairly deep, but I'm guessing that it's 6 db down at 40 hz.This is smooth and slightly kicked back sound.
It is also amazing to me that the folded-horn cabinet does not seem to resonate or cavitate to any appreciable degree. The solid, laminated birch cabinets look classy and are exquisitely finished. It's what you hope for in Italian speakers or furniture.
Best in the world? Who knows? In some systems they might be the best thing.
Edits: 07/20/14 07/20/14 07/20/14 07/20/14 07/20/14 07/22/14
"These babies might get a double run of Home Depot style speaker cable."
Why wouldn't you just run ONE set of good cables as opposed to two sets of s*&t cables.
Oz
Don't worry about avoiding temptation. As you grow older, it will avoid you.
- Winston Churchill
The manufacturer recommends a double-run of cables per driver, that is why there are two sets of terminals on the back of each speaker.Hell, I thought that I might at least try it out with some cheap cable to find out if two are indeed better than one...
Edits: 07/18/14 07/18/14 07/18/14
Perhaps they wanted the option of adding a tweeter.
I have the matching "Miranda" supertweeters, whose terminals are located separately on top of the speaker cabinets. The speakers have three pairs of terminals, nicely made ones at that.
Edits: 07/18/14
NONE...
I'm guessing that certain bi-wire cables might help give the speakers a certain sound but I'll never know for sure, because I'm not going to buy certain bi-wire cables.
Most speaker cables are too petite to give the full dynamic contrasting that was recorded at the original live event. It takes some "meat on the bone" to get the PEAK dynamics through wiring.
Bi wiring is a valid approach, and could and should be listened to. You get to decide. The wires should be EXACTLY equal in length, left to right and top and bottom and not touching the synthetic rug, elevated.
Have fun.
Jeff Medwin
Not so,,Day old bread breath,,,,The size and room lenth of wire will not hav any audible effect on this type of speaker..
> Not so,,Day old bread breath,,,,The size and room lenth of wire will not hav any audible effect on this type of speaker..
Or any type of speaker, for that matter. It would if the speed of an electron wave through wire was in the vicinity of the speed of sound. But as it's in the vicinity of 0.7 times the speed of light the length of the wire makes no difference as far as arrival time is concerned, nor is the difference in resistance, capacitance and inductance a concern with average wire lengths. Nor will using a larger gauge than required, or doubling up on the cables, have any benefit whatsoever so long as the insertion loss is less than 1dB and current capacity is adequate.
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