Jumping the Negative post on the 802D in Bi-Wiring

[Glenee]

I am going to Bi-Wire my 802D's. Some say it makes no difference( single wire or Bi-Wire) But a lot of people have mentioned that if I do Bi-Wire to be sure and jump the negative posts. What do you guys think?
Glenee

[Race Car Driver]

I have never heard of that, why would you do that?
My 802s are bi wired, no jumpers.

[caleb]

I have heard of this as well, but can't recall where.

I tried it and found it made no difference and also cant think why it should? ? ?

[Glenee]

Some speaker manufacturers have the negative post already tied together inside the cabinet, If this is the case it is not needed, I've got a request into B&W about this and when I get a reply will give my findings. I bet you Kal knows.
Glenee

[Kal Rubinson]

I don't know but I don't care. IMHO, biwiring, in all its variants, is no different from single wiring.

Kal

[fatswillie123]

Why would a company like B & W default their speakers to Bi-Wiring??, do you think it's to sell more bi-wiring wire?, I doubt it.

[Kal Rubinson]

Why would a company like B & W default their speakers to Bi-Wiring??, do you think it's to sell more bi-wiring wire?, I doubt it.

I think so. It makes their dealers happier.

Kal

[Kobus]

Why would a company like B & W default their speakers to Bi-Wiring??,

Because some of their customers believe in it.

Kobus

[Glenee]

Ole Kal ain't no big fan of the Bi-Wire stuff. I can understand that.
Glenee

[William]

Why would a company like B & W default their speakers to Bi-Wiring??, do you think it's to sell more bi-wiring wire?, I doubt it.

Since the same electrons are coming off the same transistor through only one wire which is just connected to two binding post, so bi-wiring doesn't do anything. You need to bi-transistor (bi-amp) to make any difference.

That is what the bi-post are for not just running two sets of wires from one source. :W

[RobP]

But what about B&Ws crossover design? no reason for bi-wiring there?

[Kal Rubinson]

But what about B&Ws crossover design? no reason for bi-wiring there?

No. What would? I only know of crossover designs that make biwiring impossible but none that require it.

Kal

[OC 335i]

I recently biwired (foolish me, I bought the cables before reading too much on it) and I could not hear a difference biwired vs non. I just hooked everything up yesterday. This is with BM603s and a Rotel 1057.

The cables weren't that much more though, It does look pretty though?

[Glenee]

Got a Reply from somebody at the B&W email Desk. He informed me that the 802D's already come with jumpers and yes I should put them on. Come on give me a break, this guy didn't know the first thing I was talking about. So hit reply and told him that yes they do come with jumpers, but that's not even close to what I was talking about. I used a couple of E.E. terms that he will have to get some help with. So once I get past the Email desk I will report back.
Glenee

[Race Car Driver]

Yea i didnt hear a difference, but when my wire runs are about 3 feet and I had a 100 foot spool of 12 gauge, i figured why not.

[kurtholz]

\There are a whole lot of other stereophile's who think bi-wiring makes a difference, read the most recent reviews in Hi-Fi, they talk about it some, there opinion is it's a no-brainer in improvement

I am of the same camp, but i also believe in magic miracle Cd mats, cleaners,and other foolishness

Kurt

[Kal Rubinson]

\There are a whole lot of other stereophile's who think bi-wiring makes a difference, read the most recent reviews in Hi-Fi, they talk about it some, there opinion is it's a no-brainer in improvement

Are there any real Stereophiles in Hi-Fi? :B

Kal

[kurtholz]

Are there any real Stereophiles in Hi-Fi? :B

Kal

yeah, touche, i'll give you that one,

better than absolute sound though, not sure i have ever read one review on anything the reviewed that wasnt just wonderful

you listen to, and most certainly are involved with Hi-Fi on a scale greater than most, I am surprised about your thoughts on bi-wiring, passive bi-amping,

but, it probably wouldnt pass the blind test

or the DUP test,hahahaha

assuming you know who i am talking about, the resident village idiot on stereophiles forum

Kurt

[Kal Rubinson]

There's one in every family.

In addition, not everyone at Stereophile thinks the same way nor have we all the same experience.

Kal

[amdan]

I have biwired my 802 speakers and it does make it better. However, the difference may be wholly attributed to the fact that I use two different brands of cable. Combining the two produces a better result than each on its own.

[caleb]

I personally think that the "Feel Good Factor"comes into play in this as in many other aspects of our hobby.

Hell - who wouldnt want to feel good after buying a set of $3000 speaker cables? ? ? ? 8O :B

[Glenee]

Got a Grand explanation from B&W. I don't know what it is I was very direct and to the point. These guys either don't know or don't want us to know. All iwas able to get out of them was that the negative terminals are not already tied or jumped together inside. I am not sure of this answer either. Just guess until somebody tears one apart.
Glenee

[RobP]

No. What would? I only know of crossover designs that make biwiring impossible but none that require it.

Kal

I was refering to B&W's section in the FAQ section of their website, talking about the design of their crossovers and why Bi-wiring would be a benefit to utilize. I guess I should have added that earlier, sorry. Here is a copy of it.


Bi-wiring and bi-amping

Most B&W speakers are provided with two pairs of speaker terminals; this allows you to either bi-wire or bi-amplify them. The aim of both these techniques is not to simply get the customer to spend more on cables and electronics (although no manufacturer objects to this spin off) but to improve the resolution of the speakers.

A multi-way speaker contains a crossover network that not only divides the incoming signal into different frequency ranges, appropriate to the working range of each drive unit, but also equalises each driver’s response to be flat (raw driver responses are usually anything but flat).

There are two different basic types of crossover – series and parallel. Series crossovers have each filter section wired in series between the positive and negative input terminals. It is impossible to treat each filter section individually – each interacts with the others – and such crossovers are not suitable for bi-wiring or bi-amping. But by far the most common type is parallel. Here, each driver has its own filter wired between it and the input terminals. If there is only one pair of input terminals, the inputs to all the filters are connected in parallel to that one pair of terminals. If, however, you have more than one pair of terminals, you can completely separate the inputs to each filter. Why on earth would you want to do such a thing?

In the case of bi-wiring, the answer lies in the cable connecting the speaker to the amplifier and the fact that the amplifier is a voltage source but the speaker is a current driven device (force on voice coil = magnet flux density x length of conductor in the magnet gap x current).

Firstly, all cables are a compromise. Some types of construction work better at low frequencies and others at higher frequencies. Providing separate inputs to the speaker allows you to use different cable types, each optimised for the frequency range of use.

Secondly, consider that the cable has an impedance that causes a voltage drop along its length. Now consider the current flowing along the cable. Assume for the argument that the amplifier delivers a perfect voltage waveform to the cable and the cable itself adds no distortion. However, each driver has a non-linear impedance (for example, the inductance of the voice coil alters depending on its position in the magnet gap) that causes the current to be non-linear. This non-linear current through the impedance of the cable causes the voltage drop along the cable to be non-linear and thus the voltage across the speaker terminals is also non-linear, even though it is linear at the amplifier end.

If we were just concerned with one driver, things would not be too bad. But that non-linear voltage at the speaker terminals may contain harmonics within the frequency range of one of the other drivers and that driver will reproduce them, albeit at low level. If, however, you separate the inputs to each driver filter, each driver’s distortion is kept to itself and the total system distortion goes down. We are talking small changes here, but the resolution of some modern drivers is now so good that small improvements like this are readily detectable by keen listeners.

Many people ask us whether the load on the amplifier is different if you bi-wire. It is not. As far as the amplifier is concerned, it matters not one jot whether you parallel the inputs to the filter sections at the speaker end or the amplifier end of the speaker cable.

[Kal Rubinson]

I was refering to B&W's section in the FAQ section of their website, talking about the design of their crossovers and why Bi-wiring would be a benefit to utilize. I guess I should have added that earlier, sorry. Here is a copy of it.

Yeah, I've read that before. Note all the use of "if" and "may" in it. It was undoubtedly written by a marketing department and vetted by the engineers so there were no embarrassing statements in it. Nonetheless, there's nothing informative here; just the usual techno-babble that one sees in many audiophile sites. IMHO, it was added as cover when B&W went to adding multiple terminals on the speakers.

Frankly, if B&W really wanted to deal with the issue on a responsible level, there would be some measurements and a really technical analysis. All the issues raised here are true (well, not false, anyway) but no assessment of their real effect is given.

Kal

[Glenee]

I am not very happy with the responses from B&W. I hope I never need a straight answer about anything cause I sure don't think I would get it from them. I had trouble here a little while back when I first got my 802'S ( with torque setting on the back of the midrange) all I ever got was It don't matter or just tighten to snug. Now this simple question. Dance,Dance, all around but no straight real answers. Were they bought by the Goverment when I wasn't LOOKING.
Glenee

[jmourik]

I have biwired my 802 speakers and it does make it better. However, the difference may be wholly attributed to the fact that I use two different brands of cable. Combining the two produces a better result than each on its own.

Do you mind telling us which cables you are using, just out of curiosity?
I'm currently using Blue Jeans Belden 10awg, bi-wired. Might switch to some Chinese cables if I can get my hands on them. Forgot the brand, YingWang I think...

jan

[RobP]

Jan, you should check out our forum sponser CAT Cables via the link at the bottom of the page, high quality cables, top notch construction.

[amdan]

Do you mind telling us which cables you are using, just out of curiosity?
I'm currently using Blue Jeans Belden 10awg, bi-wired. Might switch to some Chinese cables if I can get my hands on them. Forgot the brand, YingWang I think...

jan

Pure Note Enhanced Paragon for the mids and tweeters. NBS Master 2 for the bass drivers.