Any science to bi-wiring???

Tour2ma

Not intending here to flame bi-wire advocates or detractors. I'd just like to see an objective, scientific discussion of bi-wiring.

So here is the question:
From a circuits analysis standpoint, is there a reason that bi-wiring should produce a different sound than a single wire run with jumpers in place? Why or why not?

A couple of points to guide the discussion:
1. the single run is adequate gauge for the run length;
2. the jumpers are likewise assumed to be adequate for their purpose;
3. the circuit consideration shall include both speaker and amplifier internals; and
4. let's address the topic and not assault each other.

So let's hear from our electrically inclined members...

HBombToo

need input:p

8 Ohm speakers +/- ?

double up on 2 Sixteen guage stranded seems cost efffective


Twin

gidrah

Let say you have one pair of 10mm wire compared to two pair of 5mm wire!

1. The pairs in question are usually multiple stands of wire twisted together forming a cable. The strands on the inside just twist, while the outer strands kind of wrap around the inner lengths. This gives you a variance of lengths of wire within the cable which can cause time smear (or so I've read).
2. The easiest flow is on the outside (or skin) of the wire, but some is still carried by the inner core. When the surface area/ diameter ratio changes so does the skinning effect (or so I've read). Most cables are 19 strand so the thicker the cable, the thicker the strand.
3a. CONNECTIONS! Connections have a tendency to change (degrade, flavor, etc.) the signal path more than adequate wire. When wires are thicker they make less contact per strand to the terminal.
3b. Doubling up on the speaker end helps to minimize this effect. Doubling up on the amp end will also, but this labelled as "ghetto bi-amping" and scares people off.
4. Jumpers suck. Mega skin effect. The binding posts are usually ribbed on the bottom to give a better bite into cables or spades. This ribbing reduces surface contact to the hard jumper.
5. Stock and replacement jumpers have a length to them. This can cause a delay (even nanoseconds) between the signal to the low & high. Whereas identical length wires don't.


Tip! I noticed an improvement when I removed the jumpers and ran each cable to both terminals. You can either cut the sleave 2" or so down from the end and slide it up, or stip the whole length and use a 1" or so piece of tubing.

gidrah

I forgot to add that I've noticed varying results with different wire and speakers. The more efficient the speaker, the smaller the cable needs to be. I'd also assume them to be less dependant on cable changes.

If I was running 4 Ohm speakers I'd defintely give bi-wiring a chance before I invested my money elsewhere.

HBombToo

Originally posted by gidrah

2. The easiest flow is on the outside (or skin) of the wire, but some is still carried by the inner core. When the surface area/ diameter ratio changes so does the skinning effect (or so I've read). Most cables are 19 strand so the thicker the cable, the thicker the strand.

in microwave you have a point but i would never extrapolate down to 20khz....

Twin

mantis

Understanding how and why Bi wiring works or not is great info.Speakers designed to be bi wired are made that way for a reason correct?Without getting technical,if a speaker company decided to put the extra time in adding the extra set of binding posts,why not use them.

They put these metal straps in,but not all companies do that,some actually ship with speaker wire terminated with spades.(Martin Logan,Mirage,etc)

I have spoken to alot of different speaker reps and owners.They all have different Ideas on what way to wire there speakers and the quality that should be used.Vienna Accoustics feel there is no need to bi wire.They feel there crossover designs are far superior and will out perform a bi wire configuration internally.They also feel there are many benefits from using higher quality wire.Dynaudio also feels this way.You will not find there speakers bi wireable.Sonus Faber,another one who looks at things in this fashion.Then there's B&W,they feel bi wiring is a good thing and can help get the max out of your speakers.Polk also uses as seen bi wireable speaker inputs.I could go on and on here.

Alot of companis will not say"use this brand of wire because of this reason"It's all about the money and if you dig enough,you will find the reasons why.....sad but true.

As I understand bi wiring,the crossover calls certain frequencies to come to the given binding post.The top post calls for a range(mid to high or just high) and the bottom calls for the rest of it down(mid to low or just low depending on the speaker companies design).So what that means in simple terms is that using seperate conductors will allow those signals to flowdown differnent wires instead of all together in one.Seperation is whats accomplished here.

I don't mean to get off topic of being a totally technical thead here,but what I feel gets lost in technical theads is practical practice.So lets talk about that for a minute.You have your amp,cd player and speakes.You wire it up with what you bought,a single run to the speakers and have the jumpers in as from the factory.You listen to it and feel"you know what?this sounds really good and I'm happy with what I bought"Cool right?I think so.So then you start thinking about why there's these jumpers "outside of the box"and why did does the speaker have 2 inputs?So why not try 2 runs of speaker wire from the same amp output and see what it does.If sound quality is changed,there has to be a good reason for it.Better or worse.If you try this and no sound change is noticed,then there is no reason for YOU to spend extra money on something thats not doing to sound different,I'll leave it at that.......

From my experience, bi wiring have always made for the better.Every single pair of speakers that I demo'd,owned,installed has gained from bi wiring.Never did I bi wire a speaker that was single wired sound worse bi wired.Even powered towers,which the life long battle of "you can't bi wire that speaker"sounds better in a bi wired configuration, in my opnion of course.Sometimes as I noted above I think alot of you guys over think things.I do it all the time is probably why I notice it so much.Sometimes simple is better.

As most of you know I do take the stand that hearing it is much more important then understanding it.If in theory it's suppost to work or not doesn't support what I hear all the time.Think about it yourself with your own experiences and see what you come up with.I could be called an exception as I get to play with sound systems everyday.As an Installer I get to listen,configure and trail and error more then most of you.But that still doesn't mean just take my word for it.You really gotta try for yourself and see if this is worth it.

It's funny sometimes the answers I read about wiring in here.Most of you feel that the extra cost isn't worth it even without never trying it for yourself.I feel this is your lose.You can always return wire to where you bought it as long as it's premade.You want your system to sound it's best or just better then it does now correct???then why not explore all options in how to get it to where you feel it should be?

You know wire like Monstercable XP is good enough for the common speaker.I don't like bi wiring with 2 runs of it,I think a 4 conductor wire should be used.If at anything it's a neater run all in one jacket.4 conudtor wire is having 2 pairs of speaker cables in one jacket if you didn't know what that was.Monster and others make bulk 4 conductor wire.It's most likely to be cheaper then buying 2 runs of single.The bulk rule and all.

So it comes to an end with this last bit of info,I bi wire whenever possible.I try to use the highest quality of wire I can find.I also love trying different brands as I have found they sound different.Finding the correct wire,sound and price might be a difficult task.If your not willing to explore this road then I strongly suggest sticking with Monstercable as they lay the foundation for all other wires to be judged.There is tons of better sounding wire on the market.You have to find what sounds better in your system.Monstercable isn't always the less of the 2.......you decide.

Bi wiring......do it if you can.
Dan

Frank Z

I think it's safe to say that dual terminals on most if not all speakers were intended for bi-amping. If you hear a difference with your speakers bi-wired, good for you! If you do not hear a difference, even better!! You'll be able to put the money you save to better use.

If a person decides to audition a biwire set up, the best way to do it is a true double blind a-b comparison. Meditate for an hour or so before hand to clear your mind of any preconcieved notions!;) Forget about what you have heard or read about the pro's & cons. Let your ears tell the tale, and even if you do notice an improvement, is it enough to warrant spending the money on some fancy-assed wire?

Fastmerc

Cudos Frank...
As I was reading dans reply to the thread I found several thoughts passing through my mind. First thing Frank hit right off...The original intent of two sets of posts was for bi-amp. Second why would manufacturers put those there that dont really "need" to...marketing...having to do what the competition does do keep the masses buying the product. Having a buzz word to talk about. As Dan mentioned a little later in his post its all about the money. Third, I am not an EE however the observation that becasue a speaker is bi wired it somehow becomes intelligent enough to send the low frequency electrons down one set of wires and high frequencies down the other seems strange.

I hope we get some EEs to clear that up. As far as exploring the option of trying it to hear a difference...Im all up for that..have been doing those experiments whenever possible. I can see where possibly resistance levels may change by using/not using a jumper...depending on material its made of. But alas I cannot speak technically about it. Good day to all and happy listening.

HBombToo

Originally posted by Fastmerc
Third, I am not an EE however the observation that becasue a speaker is bi wired it somehow becomes intelligent enough to send the low frequency electrons down one set of wires and high frequencies down the other seems strange.

a 2nd order crossover is made up of a high and low pass filter. The high pass filter is essentially a capacitor designed to pass frequencies above ~2khz but will attenuate the frequencies below. The Low pass filter is essentially an inductor designed to pass frequencies below ~2khz but will attenuate the frequencies above.

In a speaker that has the biwire binding posts we are able to split these 2 circuits from being in parallel at the speaker and move that connection back to the amp with a Y. This is why I believe the impact is minimal but never the less noticeable. We have essentially increased the guage lowering the impedance of the wire by half with 2 identical wires.

As far as bi amping the high and low pass filters are completely isolated because the Y is moved to the output of the preamp and ran to two independent amplifiers. This in effect lowers the draw on the amps because the high will only draw power from the amp for frequencies over ~ 2khz thus leaving more overhead/reserve power for dynamic passages. This holds tru for the low pas side as well.

Another advantage to biamping is the noise floor is decreased per amp because we have decreased its bandwidth requirements. ie. Thermal Noise=kBT where k is Boltzmans constant, B is the bandwidth and T is the Temperature in units of Kelvin. As we decrease B noise decreases. Interestingly enough there is a relationship between T and B because as we decrease B we decrease the current draw per amp thereby decreasing T which is a double wammy for noise reduction.

This is the reason why biamping is more noticeable than biwireng IMHO.;)
HBomb

HBombToo

Originally posted by gidrah
1. This gives you a variance of lengths of wire within the cable which can cause time smear (or so I've read).
2. The easiest flow is on the outside (or skin) of the wire, but some is still carried by the inner core. When the surface area/ diameter ratio changes so does the skinning effect (or so I've read). Most cables are 19 strand so the thicker the cable, the thicker the strand.

as a small deviation to this topic I apologize.

gidrah your first 2 bullets are in regard to coherence. I don't know if anyone on the board has time coherent speakers? so what would be the gain with very insignificant time shifts caused by the speaker wire vrs the ~ 1/2" deviation between the woofer's and tweeter's. The 1/2" is a total swag and if need will be changed.

HBomb

Fastmerc

H,
Although I understand what a crossover does and rudementulary how it does it...it doesnt seem to me that it changes the fact that the wire/s are still carrying a full range signal till they hit said crossover.

I also understand the capacitance issue regaurding the lengths and doubleing up...but then why not just use a single run of thicker guage and lower capacitance to begin with.

Mind you I am not for or against just posing the questions

HBombToo

Originally posted by Fastmerc
H,
Although I understand what a crossover does and rudementulary how it does it...it doesnt seem to me that it changes the fact that the wire/s are still carrying a full range signal till they hit said crossover.

I also understand the capacitance issue regaurding the lengths and doubleing up...but then why not just use a single run of thicker guage and lower capacitance to begin with.

Mind you I am not for or against just posing the questions

my surrounds were wired with Radio Shack flat 16 guage. I had an extra spool so I doubled them up, "ran 2" in parallel and reconnected a bananna. I left the factory provided juper in place but form fit the 16 guage flat behind the strap and sugged them up.

Sorry but I did not get a major improvement in sound. I intend on biamping the surrounds by the internal amps of my h/k 520. but that wont be for awhile.

I think you understand quite well.

HBomb

John K.

The circuit analysis of bi-wiring(sometimes referred to as "buy wiring")can be found here (Z=impedance, W=wire, C=crossover, H=high, L=low, S=speaker)which illustrates that splitting the cable just outside the amp terminal instead of just inside the speaker terminal before the crossover results in no net electrical difference other than the lower resistance of two wires, which can be duplicated with one heavier wire(e.g. one 13 gauge wire is equal in resistance to two 16 gauge wires).

A rather interesting discussion on the point is found here , not because it repeats obvious facts, but because it's a cable company electing not to go along with the myth.

GuitarheadCA

Although I understand what a crossover does and rudementulary how it does it...it doesnt seem to me that it changes the fact that the wire/s are still carrying a full range signal till they hit said crossover.

Are you sure they're carrying that all the way up to the crossover? Think about this - if you connect speaker wire up to the terminals on the back of the amp and don't add a speaker, is there current flowing through the wires? no. The amplifier creates a potential difference between the two speaker posts, and without a complete circuit, there's no current. So from what I understand, the circuit is not completed for the lower frequencies on the high pass wire, and visa versa.

TheGrayGhost

Originally posted by GuitarheadCA
Are you sure they're carrying that all the way up to the crossover? Think about this - if you connect speaker wire up to the terminals on the back of the amp and don't add a speaker, is there current flowing through the wires? no. The amplifier creates a potential difference between the two speaker posts, and without a complete circuit, there's no current. So from what I understand, the circuit is not completed for the lower frequencies on the high pass wire, and visa versa.

That is not possible. The audio signal is complex and it is all or nothing. The crossover attenuates the frequencies above or below the crossover point depending on the design.

GuitarheadCA

hmmm, I stand corrected then. I guess I'm not an EE yet

gidrah

Originally posted by HBombToo
as a small deviation to this topic I apologize.

gidrah your first 2 bullets are in regard to coherence. I don't know if anyone on the board has time coherent speakers? so what would be the gain with very insignificant time shifts caused by the speaker wire vrs the ~ 1/2" deviation between the woofer's and tweeter's. The 1/2" is a total swag and if need will be changed.

HBomb

This doesn't have anything to do with time coherent or phased array. These time differences (extremely minute mind you) are being given to the same driver (or drivers when the crossover is used). This is not a direct influence for or against bi-wiring, just a bullet point and a stated "belief" as one reason why two lengths of 5mm cable may be better than a single length of 10mm.

2 experiments for ya:
1. Try using 1 awg cable in a short run.
2. Take one length of your favorite cable and wrap another piece around it like a barber pole (the tighter the wrap the more dramatic). Twist the ends together and connect as if one cable.
These should give an exaggerated effect to the above mentioned opinions.

GuitarheadCA

1 awg cable- what is that? like a full cm in radius? lol:cool:

gidrah

It might be that small without sheeting. Think of a time when your car needed a jump start and you thought "Damn, now those are some jumper cables!". Those would be 1 awg. How you connct them is up to you.

When I said somtheng about how more sensitive speakers are less dependant on cable differences,... ! I meant that the are less dependant on volume, but changes of overall design are very apparent.