Question On Biamping

[mike c]

no biggie ... from your succeeding posts ... it would seem that bi-wiring was MORE effective with external crossovers. IMO, a lot of people will simply use the speaker's internal crossover simply because it was what made bi-wiring so easy and cheap to do. (I have a bi-amped/bi-wired setup) because I had the extra wire and I wanted that extra 1-5 watts

 

[PENG]

no biggie ... from your succeeding posts ... it would seem that bi-wiring was MORE effective with external crossovers. IMO, a lot of people will simply use the speaker's internal crossover simply because it was what made bi-wiring so easy and cheap to do. (I have a bi-amped/bi-wired setup) because I had the extra wire and I wanted that extra 1-5 watts

Mike I think you misunderstood me. Active bi-amping uses separate external active crossovers but typically Bi-wiring still use the speaker's internal crossover. But once you remove the links at the speaker terminals, the internal crossover will be (I guess it is possible that may not be true for some) separated out into two parts. Basically one part offers higher impedance to low frequencies and the other offers higher impedance to mid/high frequencies. That forces the mid/hi frequencies to flow in one pair of wire and the low frequencies in the other pair.

That's the electrical difference I was talking about. Axiom, B&W and many other manufacturers explained the deeper details on their sites but no, as mtry cited, people (I wouldn't say all for sure) can't hear the difference, and I don't know how you can measure "audible difference" even if some people claim it exists.

 

[PENG]

You should re-read what Axiom Audio, one of your referenced sources has to say on bi-wiring:

Will it sound any different if you biwire? Some users think it does, but I've never heard any differences, nor have any of our laboratory measurements or scientifically controlled double blind listening tests ever demonstrated there are audible differences. Axiom includes the extra terminals as a nod to those enthusiasts who believe that biwiring results in audible benefits and for the bi-ampers.

They could not hear audible differences, nor measure it. So, I am not sure what other facts you have.

I don't know how audible differences can be measured but you can certainly measure the electrical difference. No I don't have much other facts because I got the facts mostly from speaker manufacturer's sites such as Axiom, B&W in the first place.

Let's quote Axiom again since you started quoting them, following is the paragraph that precedes the one you quoted:

If you look at the amplifier as a current source, then for amplifiers and receivers that are capable of supplying lots of current into low impedances, biwiring could offer theoretical advantages, particularly to loudspeakers that are linear and smooth, like the Axiom M80ti and M60ti, by eliminating potential intermodulation distortion between the low- and high-frequency portions of the audio signal. Using biwiring, this distortion would not occur because the low-frequency part of the speaker crossover would draw the current it needs for the woofers (and they need lots of current) through one speaker cable, while the midrange tweeter section would draw less current (it doesn't need as much) through its own speaker cable. This could prevent intermodulation distortion that may occur using one big “fire hose” or single speaker cable. (Using two cables per speaker will also lower total resistance to the audio signal—and that is well and good, although a single run of 12-gauge cable to each speaker will keep resistance to an insignificant level, well below 0.3 ohms.)

Note the bold and italic part that says it is not the same as one thick cable.

 

[Nick250]

I would suggest that the fact that something is measurable with sensitive electrical gear is pretty irrelevant. Audible, not audible that is what we are talking about. I would further suggest that tools to determine what is audible or not audible is readily available with a bit of detective work. The audiology department at medical school comes right to mind.

 

[sholling]

My mains manufacturer also recommeds bi-amping and using the speaker's internal crossover while biamping. Since they probably know a whole lot more about their product than I do I went with their recommendation.

 

[PENG]

I would suggest that the fact that something is measurable with sensitive electrical gear is pretty irrelevant. Audible, not audible that is what we are talking about. I would further suggest that tools to determine what is audible or not audible is readily available with a bit of detective work. The audiology department at medical school comes right to mind.

I totally agree with your first statement and have never argued otherwise. It is also obvious we can determine what is audible, but I thought it might get difficult to measure (e.g. what mtry may be talking about) the so called audible difference in sound quality when that difference is subtle to most people.

 

[JKnPA]

Active vs. Passive.....

This is an interesting subject and doing a search here revealed many posts on the subject! I have been researching the subject for only a short time and have found several good articles on the subject.
Here is one........
http://www.hometheaterhifi.com/volume_9_4/feature-article-active-speakers-12-2002.html
This is an article on wiring......... electrical factors of cables.
http://www.hometheaterhifi.com/volume_10_2/ultralink-CL414-cable-5-2003.html
*This is a link 'BuckeyeFan1' gave me.........
http://www.enjoythemusic.com/magazine/viewpoint/0403/aachapter43.htm
I hope you enjoy the articles...................
JK

 

[Nick250]

I totally agree with your first statement and have never argued otherwise. It is also obvious we can determine what is audible, but I thought it might get difficult to measure (e.g. what mtry may be talking about) the so called audible difference in sound quality when that difference is subtle to most people.

You talking in circles here. The point was whether or not bi-wiring could make an audible difference. Now you are saying that there are differences albeit subtle ones. Testing for audible differences would be a piece of cake for I think, as mentioned in my previous post.

Nick

 

[PENG]

You talking in circles here. The point was whether or not bi-wiring could make an audible difference. Now you are saying that there are differences albeit subtle ones. Testing for audible differences would be a piece of cake for I think, as mentioned in my previous post.

Nick

I wish I could find a way to clearly tell people that I have never said bi-wiring or even bi-amping makes any, subtle or not audible difference. All the time I was trying making 3 points:

1) That I had tried, but did not hear a difference myself.
2) That does not mean no one can hear a difference, subtle or not.
3) I opposed to it when and only when people claim bi-wiring is no different than using thicker wire. When such statement is made if they meant in terms of sonic difference I would not have argued. It is when they meant electrically that I have issue with. Let me emphasize again I am in 100% agreement that the electrical/physically differences I was talking about simply are NOT relevant, only sonic differences are relevant. Why then did it bother me then? I guess I was fixated on wanting things to be factual. That's all, may be I should feel "who care" and just let it go.

In my response to the 2nd part of your post, I was not referring to bi-wiring at all. I already said I agree with you about the bi-wiring part. I was curious about the methods for measuring "audible differences" in general when those differences are not in terms of volume, but in terms of subtle tonal quality, details etc. If it is easy to measure, there won't be so many posts about do amps sound similar. If I appeared to talk in circle it was certainly not my intention.

 

[mtrycrafts]

I don't know how audible differences can be measured but you can certainly measure the electrical difference. No I don't have much other facts because I got the facts mostly from speaker manufacturer's sites such as Axiom, B&W in the first place.

Let's quote Axiom again since you started quoting them, following is the paragraph that precedes the one you quoted:

If you look at the amplifier as a current source, then for amplifiers and receivers that are capable of supplying lots of current into low impedances, biwiring could offer theoretical advantages, particularly to loudspeakers that are linear and smooth, like the Axiom M80ti and M60ti, by eliminating potential intermodulation distortion between the low- and high-frequency portions of the audio signal. Using biwiring, this distortion would not occur because the low-frequency part of the speaker crossover would draw the current it needs for the woofers (and they need lots of current) through one speaker cable, while the midrange tweeter section would draw less current (it doesn't need as much) through its own speaker cable. This could prevent intermodulation distortion that may occur using one big “fire hose” or single speaker cable. (Using two cables per speaker will also lower total resistance to the audio signal—and that is well and good, although a single run of 12-gauge cable to each speaker will keep resistance to an insignificant level, well below 0.3 ohms.)

Note the bold and italic part that says it is not the same as one thick cable.

Yes, a 'theoretical' advantage by eliminating IM. But, they could certainly measure the IM in wire caused by such frequency caused current differences.
nor have any of our laboratory measurements
makes me wonder if they measured for IM and didn't find it or just at insignificant levels?

 

[mtrycrafts]

I was curious about the method of measuring an "audible difference" in general when that difference is not in terms of volume, but in terms of subtle tonal quality, details etc. If it is easy to measure, there won't be so many posts about do amps sound similar.

Detail is a subjective term, so one would have to alter a few parameters to really determine what detail means to one vs another person.
Certainly we can measure small frequency variations both in amplitude and fr drift from the original signal. We can do that with noise, distortion, etc.

From what I have read where audible differences were detected under DBT, it was a simple parameter that was rather greatly different: fr variation in a band( a rather long article but worth reading- an amp modified from 3.5kHz and up certainly was different http://home.att.net/~Wirebnder/articles/article_14.htm)
Or, distortion and noise were high order.
Soundstage is a phase difference between left and right channels.
There is an interesting CD to demonstrate this.

I believe that subjective, non-standard terms assigned by listeners may be chasing ghosts

 

[mtrycrafts]

. Besides, you did visit the B&W and other speaker manufacturer's sites, right?

I am enjoying this, thank you for keeping it going.

No, I didn't They better be saying the same thing as Axiom or my confidence would be shaken in them Cannot have multiple truths about 2+2.

Yes, I am enjoying this too, a learning experience for me. I am too young to give up learning as then it is time to visit the dark depth of the endless universe.

 

[PENG]

Yes, a 'theoretical' advantage by eliminating IM. But, they could certainly measure the IM in wire caused by such frequency caused current differences.
nor have any of our laboratory measurements
makes me wonder if they measured for IM and didn't find it or just at insignificant levels?

I wonder if they meant their laboratory measurements could not measure what could contribute to "audible difference (quality wise)". As for the IM distortion itself, I agree, if exists, should be measurable.

B&W and several other sites basically say the same thing so I can assure you they won't shake your confidence.

 

[mtrycrafts]

B&W and several other sites basically say the same thing so I can assure you they won't shake your confidence.

Great Then I saved a bunch of time searching and reading. I am far from a dual core processor when it comes to reading

 

[PENG]

From what I have read where audible differences were detected under DBT, it was a simple parameter that was rather greatly different: fr variation in a band( a rather long article but worth reading- an amp modified from 3.5kHz and up certainly was different http://home.att.net/~Wirebnder/articles/article_14.htm)
Or, distortion and noise were high order.
Soundstage is a phase difference between left and right channels.
There is an interesting CD to demonstrate this.

I believe that subjective, non-standard terms assigned by listeners may be chasing ghosts

That's exactly what I was looking for, ways to measure, not just DBT. I am going to spend the next hour or two reading it. Thanks again for the link.

 

[rmongiovi]

I don't see how bi-wiring could prevent that IM distortion they're postulating. It doesn't matter where you split the wires. Having separate speaker cables from the amp's binding posts outward won't prevent one current path from stealing amperage from the other once you get to a single current path inside the single amp. Unless there are separate amplification circuits inside the amplifier that lead to the separate binding posts, it's all the same to the electrons.

That said, I plan on bi-wiring for a different reason: just because my speakers have bi-amp/bi-wire terminals. There is a measurable signal loss at each connection in the wire. If I don't bi-wire, I have to jumper one set of terminals on the back of the speaker to the other. That means the the current path to the woofers has two connection losses: at the amp's binding posts and at the speaker's binding posts. The midrange and tweeter, however, will have three connection losses: the amp's binding posts, the first set of speaker binding posts, and then the second set of speaker binding posts.

Will I be able to hear the difference? Almost assuredly not. But since I'm not silly enough to buy expensive wire, I can't think of a good reason to use the jumper between the two sets of speaker binding posts.

Of course, this argument doesn't take into account any of the wiring inside the amp or the speaker, but I'm really not going to attempt to quantify this any further.

 

[mtrycrafts]

just because my speakers have bi-amp/bi-wire terminals. There is a measurable signal loss at each connection in the wire.

I would be most interested in those losses, in dB spl, per junction I bet it is less, waaay less than caused by skin effect, about .04 dB or less.

 

[rmongiovi]

I would be most interested in those losses, in dB spl, per junction I bet it is less, waaay less than caused by skin effect, about .04 dB or less.

Well, I don't believe in skin effect at auditory frequencies. Unless my hearing extended into the megahertz I wouldn't want to worry too much about that.

But each connector is a place where oxidation, loose connection, etc. has a chance to cause measurable signal loss and/or noise introduction. Especially in a speaker, where vibration is a desired goal, I think avoiding extra connections is a sensible precaution.

As with all things involving human senses, your mileage may vary....

 

[JKnPA]

Jumpers.......... ???

Unless the 'jumpers' are loose or dirty, the signal loss is negligible!
By disconnecting the jumpers and uncoupling the 'passive filters' at that point, you reduce the 'interaction of those filters', because you are now using two wires going back to the amplifier............. IMHO.
If you bi-amp.......... you remove that problem entirely!

 

[rmongiovi]

What do you mean by "passive filters"?

The jumpers that came with my speakers are a skinny little wire with a spade on one end and a banana plug on the other. I hate banana plugs. You can't convince me they maintain good contact; they just feel flimsy.