Bi-wiring/Bi-amping explained

[vc69]

Originally Posted by F1nut

No, it would look like this;

89dB - 1 watt
92dB - 2 watts
95dB - 4 watts
98dB - 8 watts
101dB - 16 watts
104dB - 32 watts
107dB - 64 watts
110dB - 132 watts
113dB - 264 watts
116dB - 528 watts

So, for every 3dB increase it takes double the power.

Ok, I was confused.

Thanks.

[sTiLlLeArNiNg]

Originally Posted by anhchungdoan

Hey, take it easy on the Canadian! My beautiful lady and my "the one and the only" female pianist and jazz singer, Diana Krall is from where you already know.

Originally Posted by anhchungdoan

Hey! take it easy. Now you guys spoil my week-end. Iggloo and dogsleds? Another attempted shot at another pretty woman from Alaska. I know what you guys are doing. I do not care if she sees Russia from her house, I like pretty woman.

Diana Krall, Jazz singer ( Canadian) & Sarah Palin ( Alaskan) = 2 beautiful components.

No worries man! In case you didn't notice TECHNOKID and i are both Canuck's lol

Originally Posted by TECHNOKID

We Canadians don't know dip $h1t about audio thus the reason for coming out here, right?

Yup! I'm sTiLlLeArNiNg

[Lasareath]

Originally Posted by steveinaz

Seeing a post from yourself 6 years ago, is like the first time you heard your voice on a cassette recorder-----you sound like a dork...

LOL

Welcome to Club Polk Steve!

Originally Posted by F1nut

Did you have the fronts set to small or large before and what are they set to now?

I just can't figure out where i set my 1.2's to large on my Adcom GFP-750!!!! ARGH!!!!!

[anhchungdoan]

Originally Posted by Lasareath

Welcome to Club Polk Steve!





I just can't figure out where i set my 1.2's to large on my Adcom GFP-750!!!! ARGH!!!!!

IMS, I set all my full range speakers @ small/ 80hz for movies. IMHO, if you have a GOOD sub , it works better that way. If your sub does not go down ,say to 20hz you may want to tried both way and see which way sounds better to your ears.

[warlocks1]

Give it a try Sal! I am going to try setting my 1.2tl's to small and crossover at 120 hz. I will let my center handle the low end.

[JotGloky73]

from the lack of response I figure that must be a bad idea. Guess Ill start bidding on some expensive, 20 year old wiring harnesses on ebay:

[F1nut]

What are you talking about?

[Krazyz1]

Since this started out a explanation of bi-wiring/bi-amping , here is my scenario. Some speakers you can hear a difference when bi-wired. On my RTiA9's made a big difference. The only way I can describe it is that the music sounds meatier or more robust. Not just my oppinion , others that had heard it before and after agreed.This is the part where I be come un-educated and need some education from people in the know. Does the amplifier read the ohm value still at the rated 8 ohm , or bi-wired does the amp see it as a 4 ohm load?????? I don't know and this is what got me wondering. For sake of argument a ROTEL RB-1090 will support 4 speakers in standard wiring mode , but will only support 2 if bi-wired. Why???????

[sTiLlLeArNiNg]

TBH Krazy i think the biggest improvement come's from removing the stupid jumper bar's that come on all 4 post speaker cabinet's and using speaker wire

I'm currently trying to build some cable's based off of Canare's 4s11 which is a 4 conductor cable, i will be pairing up the lead's on the AMP/AVR side and running each separate lead to the corresponding terminal's on the speaker side. I have pretty much everything i need except for the terminal's which i hope to get ordered this week or early the following week

I'm not shure but i think with your Rotel example you would be bi-amping and not just bi-wiring I would assume that there would be more noticeable gain from bi-amping vs bi-wiring

I still beleive that bi-wiring produce's noticeable improvement's and i beleive those improvement's vary depending on the speaker

Trying to bi-wire/bi-amp is not very costly IMO (provided you have the 2nd amp for bi-amping) as you can get Canare 4s11 (which is very highly reccomended by many people) usually for $1.19/ft - $1.39/ft and since you are in the state's most companies offer free shipping to lower 48 sate's on order's over $100

[Krazyz1]

I agree with most of what you are saying , but if you go to Rotel home page and go into archive downloads it shows distinctly on the rear panel wiring 4 speakers hooked up 2 strand only and also only 2 speakers wired to it that are bi-wired. I fully understand the difference between the 2. Bi-wiring is removing jumper bars at speaker terminal and running 2 set of speaker wires to amp and the you have 2 + cables on red term. and 2 - wires on black term. Bi-amping is essentially the the same EXCEPT each cable would be connected to seperate amps. If I am in error feel free to correct me. Still no answer on ohm issue that is my biggest curiosity.Because if your speakers are essentially rated 8 ohm and because non stand wiring might make the amp read 4 ohm , I would think that would open the door to over power your speakers since amps have 1 rating @ 8 ohm and 4 ohm almost always higher. That's why the ohm issue is important to me. I don't want to think I am only shoving 200w. because 8 ohm , where in reality I might be running 350w. because I DON'T know if amp reads the load different because of bi-wiring. Someone please clear this up for me. Thank you.

[TECHNOKID]

Originally Posted by Krazyz1

I agree with most of what you are saying , but if you go to Rotel home page and go into archive downloads it shows distinctly on the rear panel wiring 4 speakers hooked up 2 strand only and also only 2 speakers wired to it that are bi-wired. I fully understand the difference between the 2. Bi-wiring is removing jumper bars at speaker terminal and running 2 set of speaker wires to amp and the you have 2 + cables on red term. and 2 - wires on black term. Bi-amping is essentially the the same EXCEPT each cable would be connected to seperate amps. If I am in error feel free to correct me. Still no answer on ohm issue that is my biggest curiosity.Because if your speakers are essentially rated 8 ohm and because non stand wiring might make the amp read 4 ohm , I would think that would open the door to over power your speakers since amps have 1 rating @ 8 ohm and 4 ohm almost always higher. That's why the ohm issue is important to me. I don't want to think I am only shoving 200w. because 8 ohm , where in reality I might be running 350w. because I DON'T know if amp reads the load different because of bi-wiring. Someone please clear this up for me. Thank you.

Your question is not an easy one as speakers are wired differently from brand to brands. IE: many Polk speakers will give you a higher impedance when the jumper are connected since the Xo provides for high impedance input however, when the jumper is/are removed, you will read the 8 ohms impedance at one set of speaker connector/leads while you still read high impedance at the other set. Even without elaborated Xo, you still read only 8 ohms no matter what because there is always some capacitors to isolate drivers from each other in order to avoid impedance drop with drivers connected in parallell (this is also basic Xo principle as the capacitor are chosen to pass specific frequencies while blocking others). Your best bet is to simply use a multimeter to check how your specific speaker reacts when you measure them without the jumpers. Personally, in order to read a change in impedance value when removing the jumpers would lead me to believe the speaker has a piss poor design. As I pointed out, your best bet is to experiment by measuring how your specific speakers react when you do remove the jumper. In fact, my personal opinion is that upgrading your Xo is a much better improvement and investment than wasting time and money on cables in order to bi-amp.

Cheers!
TK

[WilliamM2]

Still no answer on ohm issue that is my biggest curiosity.Because if your speakers are essentially rated 8 ohm and because non stand wiring might make the amp read 4 ohm , I would think that would open the door to over power your speakers since amps have 1 rating @ 8 ohm and 4 ohm almost always higher. That's why the ohm issue is important to me.I don't want to think I am only shoving 200w. because 8 ohm , where in reality I might be running 350w. because I DON'T know if amp reads the load different because of bi-wiring. Someone please clear this up for me. Thank you.

Bi-wiring is just moving the jumper from the speaker to the amp terminals. It won't change the load on the amp at all.

[TECHNOKID]

Originally Posted by WilliamM2

Bi-wiring is just moving the jumper from the speaker to the amp terminals. It won't change the load on the amp at all.

Humm, that's an interesting way to put it (and also very easily understood also )!

Cheers!
TK

[CoolJazz]

...and to clarify for the record, as established before, using a voltmeter does not tell you the actual impedance value of a speaker at all!

CoolJazz

[TECHNOKID]

Originally Posted by CoolJazz

...and to clarify for the record, as established before, using a voltmeter does not tell you the actual impedance value of a speaker at all!

CoolJazz

Using a multimeter or ohmeter (not voltmeter) will give you the static/DC impedance of the speaker(s) (read the impedance/resistance of the coil) and this is exactly what is shown in the speaker's specs/user manual. Yes, the dynamic impedance is a different ball game but the static/nominal impedance is always the reference when talking about impedance matching. OK, I went back and I did mention a multimeter (NOT VOLTMETER) which measures resistance and impedance). Multimeter = measures résistance, coils, combination of, the only thing it will not measure is capacitance unless it has the feature to do so and of course this is measure off circuit/line!

For people who do not understand how to measure the DC impedance of a speaker, here it is:

Measuring speaker nominal impedance
If you just want to find out the nominal impedence of the speaker e.g. ist it 4, 8 or 15 ohms then there is a rough & ready way. Just use your multimeter to measure the DC resistance of the voice coil i.e. across the speaker terminals (with nothing else connected) and multiply the answer by 1.3. So if the DC resistance is say 6 ohms then the speaker is nominally 8 ohm impedance.

The single most dominant branch of the model is the voice coil DC resistance, Re. It's going to be in series with everything else we will look at (you mentioned "stray capacitance". Yes, there is some, but it's magnitude is absolutely miniscule compared to all other components so it can be ignored).

http://www.epanorama.net/documents/a...impedance.html

Cheers!

[vc69]

Originally Posted by TECHNOKID

For people who do not understand ... <snip>

Cheers!

Good grief.

The load (impedance) presented by a single speaker does not represent the load presented by a typical home speaker with a crossover network and more than one driver (woofer, mid, tweeter).
also
The impedance of *any* speaker varies according to the frequency(s) and amplitude of the signal being reproduced.

Hence CoolJazz's statement.

[Krazyz1]

LOTS of good info. I will take some variables out and be more specific. I have Polk RTiA9's with jumper bars removed. They are bi-wired and sound " meatier " , more substance. I like the sound improvement. I just didn't know if the amp would now think it is hooked up to a 4 ohm speaker instead of a 8 ohm. Hope I clairified a little more understandable the concern.

[GV#27]

Originally Posted by vc69

The impedance of *any* speaker varies according to the frequency(s)

True that,it is not a pure resitance.

[F1nut]

Originally Posted by Krazyz1

LOTS of good info. I will take some variables out and be more specific. I have Polk RTiA9's with jumper bars removed. They are bi-wired and sound " meatier " , more substance. I like the sound improvement. I just didn't know if the amp would now think it is hooked up to a 4 ohm speaker instead of a 8 ohm. Hope I clairified a little more understandable the concern.

If you replaced the jumpers with high quality wire, you would get the same result.

Your amp is still seeing a nominal 8 ohm load.

[Krazyz1]

Thanks for the concrete answer

[sTiLlLeArNiNg]

Originally Posted by F1nut

If you replaced the jumpers with high quality wire, you would get the same result.

I don't think it need's to be "high quality" i think pretty much any speaker wire is better than the stock jumper plate's

[dorokusai]

The plates just stink....jumpers are cheap and easy to make.

[WilliamM2]

If that the case, the traces on the crossover circuit board must really stink. And what about the plain metal tabs on the drivers?

[F1nut]

William....please stifle.

[dorokusai]

Originally Posted by WilliamM2

If that the case, the traces on the crossover circuit board must really stink. And what about the plain metal tabs on the drivers?

I agree.

[sTiLlLeArNiNg]

Trace's on the circuit board should be best grade copper, speaker terminal's ARE questionable. If you like your stock jumper bar's use 'em I bet ya if ya peel 'em off and use some speaker wire you would hear a difference too

[TOOLFORLIFEFAN]

I replaced my stock jumpers on my 1.2's and it made a world of difference.

Has anybody ever got inside the cabenets and just wired everything to the bottom post's?