Biamping with Onkyo TX-NR5008 vs 1 amp and Onkyo PR-SC5508 - AVS Forum
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post #1 of 38 Old 05-22-2011, 05:28 PM - Thread Starter
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Hey gang. Currently I have a Rotel RSP 1068 pre/pro. I am looking to upgrade to something that can handle 3D, combine all my HDMI into one processor, lossless audio, Audessey XT32, and also give me the full benefits of my Bluray player. I had originally narrowed my choice down to the Onkyo PR-SC5508 since I only needed a pre/pro. I then started looking at the TX-NR5008 since I would then be able to biamp my current speakers (right now they are being powered by one amp). After doing some cost comparisons and calling around I can pickup the TX-NR5008 for about $200 less than the PR-SC5508. So now my quest has evolved into, is it worth picking up the TX-NR5008 and getting biamp ability, and then having "extra" power if I should decide to go to 9.1? Or should I stick with the PR-SC5508 since it will be slightly cleaner, even though I RARELY listen to music at reference ranges? BTW, my current amps don't have the balanced audio option, so that doesn't really mean much to me (they are also only located about two feet from my pre/pro). If I biamp I would probably use my current Rotel amp for my mid/highs and use the Onkyo to power the lows since the Rotel is 125X2, but my guess is it's also a better match for the uppers of my speakers. Also, are there any inherent flaws in my logic of biamping this system?

PS - My current Equipment is a PS3 for Bluray, Marantz DV6500 for DVD, Rotel RB 1070 and Rotel RMB 1075 for amplification, and Dali Euphonia MS4 fronts, Dali Euphonia CS4 center, and 4 Dali Ikon wall mounts for the side/rear channels.
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post #2 of 38 Old 05-22-2011, 07:33 PM
 
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Passive bi-amping, especially with the speakers you have, will be a serious waste of time.

You would need to do active bi-amping to see any benefit.

I would get the pre-pro then get an outboard crossover
http://www.audiogon.com/cgi-bin/cls....I-electronic-c (excellent choice...and ridiculously inexpensive)

Then use your present Rotels to run the 7 channels...but your fronts(and whatever else with another crossover) are actively bi-amped.
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post #3 of 38 Old 11-29-2012, 10:51 AM
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I am looking to bi-amp a pair of B&W speakers, has anyone actually used the PR-SC5508 to drive monoblocks?

Thanks.

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post #4 of 38 Old 11-29-2012, 11:23 AM
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Quote:
Originally Posted by schan1269 View Post

Passive bi-amping, especially with the speakers you have, will be a serious waste of time.


You would need to do active bi-amping to see any benefit.


I would get the pre-pro then get an outboard crossover
http://www.audiogon.com/cgi-bin/cls....I-electronic-c (excellent choice...and ridiculously inexpensive)


Then use your present Rotels to run the 7 channels...but your fronts(and whatever else with another crossover) are actively bi-amped.

+1. Also, there's no guarantee that the sensitivity of the Rotel would match that of the Onkyo, which means the tweeters would either be too loud or too quiet, depending on the relative sensitivities.

But mostly, passive biamping is seldom worth while. Playing real content, your tweeters use maybe 20% of the power that the woofer(s) require, so you just can't gain much power. And even if you doubled power, you'd be talking about a 3 dB increase, which folks general identify as "one notch" louder. If you are driving your receiver's amps into audible clipping, passive biamping might benefit you by sending the higher frequency harmonics from the clipped signals only to the woofers, where the crossover would roll those frequencies off, leaving the amps driving the tweeters, since they're just coasting along, to provide an undistorted signal to the tweeters. At least equal benefit would come from using an amp that can deliver the necessary power without clipping without resorting to the biamping kludge. And, yes, I biamped my Sonus Fabers and my Maggies for a time, so I have some real world experience.

As to compatibility in general unless the B&Ws are a very difficult load to drive (ie drop to very low impedance somewhere in tehir range, there is not likely to be anything more or less compatible about either amp.
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post #5 of 38 Old 11-29-2012, 11:51 AM
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Active crossovers are difficult to implement properly, not as difficult as passive ones, but still requiring quite a bit of knowledge. While the crossover pointed out is inexpensive it does not implement an equalizer, essential for baffle step compensation and other functions common to good crossovers, whether passive or active. Therefore if you pursued this difficult task I would advise purchase of a miniDSP.
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post #6 of 38 Old 11-29-2012, 02:17 PM
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Not to mention you have to be comfortable with ripping the passive crossovers out of your speakers, or finding some way to bypass them. And of course, hook up to the wrong drivers just once and you're likely to be looking fo new tweeters.
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post #7 of 38 Old 11-29-2012, 02:34 PM
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Do you guys know (specifically) if the PR-SC5508 has internal electronic crossovers when using the bi amp feature. The manual implies that there isnt by omission. Which in turn sounds like all the pre/pro is really doing is making a "Y" connection inside of the pre/pro which is exactly what I want: let the speakers sort the signal out via their own crossovers.

I have several Marantz mono blocks and would like to experiment. And yes, the B&Ws do drop to a 3 ohm load.

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post #8 of 38 Old 11-29-2012, 03:42 PM
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No the 5508 does not have internal electronic crossovers, I have one. And biwiring/passive biamping is just a waste of wire.
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post #9 of 38 Old 11-29-2012, 05:37 PM
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Bi-amping, active or passive, does not in itself provide any additional power. if you have a 100 W amp operating full-range, then split the signal into two frequency bands each driven by a 100 W amp, the most power available in either band is still 100 W.

"After silence, that which best expresses the inexpressible, is music" - Aldous Huxley
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post #10 of 38 Old 11-29-2012, 09:39 PM
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Could someone please explain what “passive” bi-amping is? I am assuming then that we also have “active” bi-amping? What’s the difference.

I had a chance to play around with the equipment tonight and was able to bi-amp my speakers using four Marantz mono blocks. I used the 125W for the highs and the 200W for the lows. Overall I am pretty sure there was a good amount of improvement (and I do not mean loudness). I used an SPL meter to make sure I was comparing songs at the same levels.



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post #11 of 38 Old 11-30-2012, 01:00 AM
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Bi-Amping normally means using a preamp with an active 2-way crossover in the signal path followed by two power amps (one for each branch) to feed the drivers directly (low / mid+high). The drivers are coupled (advantageously) directly to the power amp output stages when you got a 2-way system. Note: The ideal situation would be to have as many actively filtered branches incl. the corresponding power amps as there are drivers in the system.
On a 3-way or more system the bass branch is driven directly (without a passive crossover) and the mid+high branch is driven through a passive crossover, which splits up the frequency range for the tweeter and mid driver. Unfortunately that removes some of the advantages of bi-amping.

"Passive" bi-amping is just a gimmick like b-wiring, because you are feeding the same full-range signal through two amps into passive crossovers, splitting up the frequency range for the bass and mid/high range. Both signal branches thus are going through a passive crossover like in a conventional system. This removes almost completely the electrical and acoustical advantages of the bi-amping concept.
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post #12 of 38 Old 11-30-2012, 01:23 AM
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+1
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post #13 of 38 Old 12-10-2012, 08:25 PM
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.......So, am I right in thinking if I have my speakers bi-amped using the Bi-Amp/Rear Surround terminals on my 5008 I am wasting my time (and a pair of speaker terminals) as it is Passive?
If so, why is the facility to do this even there in the first place??
Am I just as well removing the speaker cable and replacing the links, and just use one speaker cable to the standard left and right channels?
Also if passive bi-amping is a waste of time how have so many been fooled for so long?, and how many people would be prepared to actively bi-amp?
If passive bi-amping is such a poinless excercise, why do speaker companies even bother with more than one set of binding posts, especially on high end equipment? Would it have anything to do with the money made from all that extra cabling and purchasing of extra amps maybe?
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post #14 of 38 Old 12-11-2012, 04:20 AM
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^^^

- yes...

- because people hold "beliefs", and any smart marketer will cater to those "beliefs"...

- yes...

- because people have "beliefs", and in the a/v world, those "beliefs" can be completely irrational, yet still fiercely held...

- not many... active bi-amping requires far more knowledge than 99.99% of posters have...

- because people hold "beliefs"... those "belief holding people" are especially prevalent in the "high end" group...

side note to the above: never forget that human beings are highly susceptible to bias, both conscious and unconscious... you CANNOT "control" this yourself (unless you are a borg, or possibly a vulcan)... that is why you will see many of us insist that "without a bias controlled test, you have no valid results"...

- chris

 

my build thread - updated 8-20-12 - new seating installed and projector isolation solution

 


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post #15 of 38 Old 12-11-2012, 04:31 AM
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There are benefits to actively "bi-amping" (in a sense most are "bi-amping by having a separate amp and crossover for their subs) and "tri-amping" but as stated few would be so inclined because of the expense and are sufficiently knowledgeable. I do actively "tri-amp" with the subwoofers having their own amp (as usual), as do the midwoofers and tweeters. This has been made much easier because of miniDSPs. Its a shame that audio companies promote passive bi-amping when its known to be of no value except to the manufacturers of cables.
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post #16 of 38 Old 12-11-2012, 05:02 AM
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Quote:
Originally Posted by Wavod View Post

.......So, am I right in thinking if I have my speakers bi-amped using the Bi-Amp/Rear Surround terminals on my 5008 I am wasting my time (and a pair of speaker terminals) as it is Passive?
If so, why is the facility to do this even there in the first place??
Am I just as well removing the speaker cable and replacing the links, and just use one speaker cable to the standard left and right channels?
Also if passive bi-amping is a waste of time how have so many been fooled for so long?, and how many people would be prepared to actively bi-amp?
If passive bi-amping is such a poinless excercise, why do speaker companies even bother with more than one set of binding posts, especially on high end equipment? Would it have anything to do with the money made from all that extra cabling and purchasing of extra amps maybe?

You have to differentiate between, what manufacturers do to sell their products to certain type of consumers (called marketing) and what's reliable as proven theory and science behind it.
In a highly competitive market speaker and amp manufacturers will go to great length to provide food to those who believe in certain things no matter if it has any valid technical base. In the past active bi-amping has been one of the more interesting concepts for high-end speaker systems (often costing thousands), which where to overcome certain limits in speaker design.
To garner to current consumers manufacturers will strap everything, which seems "unnecessary", to lower cost for those buying in mass market segments but still have that catch phrase "bi-amping" visible.

Some more exotic (and expensive) speaker systems will apply an all-active multi-amp concept, by using active cross-over electronics with adjustable DSP filter designs followed by individual and direct coupled power amp stages handling each and every driver on its own, thus making the most of "speaker control". Another area, where this concept is quite common, are (mostly two way) near-field monitors for the studio environment, where everything is integrated into each active speaker system with shelving filters and so forth.

All those systems have something in common, they are actively bi-amped or tri-amped, not passively, like in the more mass market oriented consumer entertainment world.
Just think about, what's really going on and you will realize that passive bi-amping (and bi-wiring) is just what it is, a marketing gag.
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post #17 of 38 Old 12-11-2012, 05:08 AM
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Quote:
Originally Posted by Wavod View Post

.......So, am I right in thinking if I have my speakers bi-amped using the Bi-Amp/Rear Surround terminals on my 5008 I am wasting my time (and a pair of speaker terminals) as it is Passive?

Yes.
Quote:
If so, why is the facility to do this even there in the first place??

It is believed by some to give the receivers with the feature a competitive advantage. The incremental cost of adding the feature is pretty close to nil.
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Am I just as well removing the speaker cable and replacing the links, and just use one speaker cable to the standard left and right channels?

Yes.
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Also if passive bi-amping is a waste of time how have so many been fooled for so long?,

The best way I know of to fool yourself convincingly is to do a typical audiophile evaluation - no level matching (probably and hopefully not relevant in this particular case), don't be rigorous about listening under identical conditions, and know what you are listening to when you are listening.

Reality is that a certain percentage of the people who compare passive bi-wiring to normal wiring will inadvertently reverse one set of wires. They will hear a difference! Audiophiles have as strong tendency to equate any difference with an improvement.
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and how many people would be prepared to actively bi-amp?

Almost nobody. Probably less than half of the people who try it because it involves re-engineering the speaker almost from scratch.
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If passive bi-amping is such a poinless excercise, why do speaker companies even bother with more than one set of binding posts, especially on high end equipment?

It is believed by some to give the speakers with this feature a competitive advantage. The incremental cost of adding the feature is pretty close to nil.
Quote:
Would it have anything to do with the money made from all that extra cabling and purchasing of extra amps maybe?

You bet ya!

Put the pieces together

(1) Most audiophile equipment comparisons will not be comparisons of apples to apples but will inadvertantly introduce real differences that are audible.
(2) Audiophiles are highly prone to perceive differences even when there are none.
(3) Audiophiles are highly prone to perceive any difrerence real or imaginary as an improvement.

The above is based on the well-known fact that people tend to see what they are told to see and hear what they are told to hear.

Note that I'm not putting myself above anybody else - under the given conditions I can and have made the same mistake(s) for years and years. The difference is that someplace along the way I learned how to do careful listening tests that held more influences constant, and the results were pretty stunning.
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post #18 of 38 Old 12-11-2012, 05:11 AM
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Quote:
Originally Posted by gurkey View Post

Quote:
Originally Posted by Wavod View Post

.......So, am I right in thinking if I have my speakers bi-amped using the Bi-Amp/Rear Surround terminals on my 5008 I am wasting my time (and a pair of speaker terminals) as it is Passive?
If so, why is the facility to do this even there in the first place??
Am I just as well removing the speaker cable and replacing the links, and just use one speaker cable to the standard left and right channels?
Also if passive bi-amping is a waste of time how have so many been fooled for so long?, and how many people would be prepared to actively bi-amp?
If passive bi-amping is such a poinless excercise, why do speaker companies even bother with more than one set of binding posts, especially on high end equipment? Would it have anything to do with the money made from all that extra cabling and purchasing of extra amps maybe?

You have to differentiate between, what manufacturers do to sell their products to certain type of consumers (called marketing) and what's reliable as proven theory and science behind it.
In a highly competitive market speaker and amp manufacturers will go to great length to provide food to those who believe in certain things no matter if it has any valid technical base. In the past active bi-amping has been one of the more interesting concepts for high-end speaker systems costing thousand, which where to overcome certain limits in speaker design. To garner to current consumers manufacturers will strap everything, which seems "unnecessary", to lower cost for those buying in mass market segments but still have that catch phrase visible.

Some really exotic (and expensive) speaker system will apply an all-active multi-amp concept, by using active cross-over electronics with adjustable DSP filter designs followed by individual and direct coupled power amp stages handling each and every driver on its own.
Another area, where this concept is quite common, are (mostly two way) near-field monitors for the studio environment, where everything is integrated into each active speaker systems with shelving filters and so forth.

All those systems have something in common, they are actively bi-amped or tri-amped, not passively, like in the more mass market oriented consumer entertainment world.
Just think about, what's really going on and you will realize that it is just what it is, a marketing gag.

I think we need to be careful about appearing to pooh-poohing the concept of active mutli-amping. It holds great potential and this potential has manifested itself in a number of outstanding products. Thng is the active biamped or triamped speaker needs to be purpose built and engineered from scratch to do what it does. Mixing switchmode amps and power supplies into the existing recipe involving right-sized power amps and DSPs makes this approach even more attractive.

It has had more acceptance in the professional market because that market is more pragmatic. Audiophiles don't want to give up their right to buy their amps and speakers separately.
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post #19 of 38 Old 12-11-2012, 05:12 AM
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Almost nobody. Probably less than half of the people who try it because it involves re-engineering the speaker almost from scratch.

Yes, one must be a DIY speaker builder in order to do it. A gratifying but expensive (re. buying amps for active crossovers) hobby.
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Originally Posted by arnyk View Post

I think we need to be careful about appearing to pooh-poohing the concept of active mutli-amping.

I don't think anyone is pooh-poohing the concept of active multi-amping here, more exposing the ineffectiveness of passive bi-amping for what it is. rolleyes.gif
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post #21 of 38 Old 12-11-2012, 09:28 AM
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Originally Posted by Wavod View Post

I don't think anyone is pooh-poohing the concept of active multi-amping here, more exposing the ineffectiveness of passive bi-amping for what it is. rolleyes.gif

Would you agree with the following statements:

1. There would be a benefit in the following scenario: Speakers can handle 500W. I have a 200W amp driving them, single wire. But then I add two 200W amps and bi-amp them. There should be an improvement due to the extra power?

2. There would be no benefit in the following scenario: Speaker can handle 500W. I have two 200W amps bi-amping them. I remove the two 200W amps in favor of a single "comparable quality" 400W amp that is single wired. There should be no perceived sound difference?

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Scenario #2 will result in much more significant change in sound than scenario #1.

Two 200W amps in this sort of arrangement won't deliver near the power to the speakers as does one 400W amp. Doesn't work that way.

Just because there is a knob doesn't mean you should turn it.
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post #23 of 38 Old 12-11-2012, 11:52 AM
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Think of it this way: You have a 200 W amp driving full-range, providing 200 W total to the speaker (highs and lows). Now, bi-amp, using two 200 W amplifiers. You have a max of 200 W to the bass and 200 W to the highs, exactly the same as you had with a single 200 W amp driving highs and lows. You do not get 400 W into either frequency band. No net power increase to the speaker, you have just split where the power goes into two frequency bands. A 400 W amp is twice the power to the speaker (albeit that is only 3 dB, a pretty modest headroom increase). This is all true for active or passive bi-amping if you use the same size amps. The usual benefits from (active) bi-amping arise from eliminating the passive crossovers in the speakers and optimizing power distribution by e.g. using a much larger (higher-power) amp for the bass than the treble.


I thought Onkyo actually allowed active bi-amping using a crossover in the receiver? Still of arguable benefit in a consumer speaker where the crossovers remain in place.

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post #24 of 38 Old 12-11-2012, 12:15 PM
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Originally Posted by BVLDARI View Post

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Originally Posted by Wavod View Post

I don't think anyone is pooh-poohing the concept of active multi-amping here, more exposing the ineffectiveness of passive bi-amping for what it is. rolleyes.gif

Would you agree with the following statements:

1. There would be a benefit in the following scenario: Speakers can handle 500W. I have a 200W amp driving them, single wire. But then I add two 200W amps and bi-amp them. There should be an improvement due to the extra power?

The only improvements that matter are the ones that are audible. Power only adds to sound quality if it is needed to avoid audible distortion in the power actually sent to the speakers.

Having a 100 watt amp putting out 10 watts is not necessarily any better sounding than having a 200 watt amp putting out 10 watts, How do you know how much power you are actually using.

Please remind me again about the benefits of driving a car that can go 200 mph on a road where the law enforcement makes it highly inadvisable to go faster than 70.
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2. There would be no benefit in the following scenario: Speaker can handle 500W. I have two 200W amps bi-amping them. I remove the two 200W amps in favor of a single "comparable quality" 400W amp that is single wired. There should be no perceived sound difference?

A 200 watt ( 8 ohm) power amp can only provide about 40 volts of audio to the speaker. 2 200 watt amps each driving part of a speaker (which is what passive biamping does) still can't deliver any more than 40 volts to the speaker. If you want to apply 500 watts to an 8 ohm speaker you need to come up with much more voltage (about 64 volts) than 2 or any number of 200 watt amps can provide.
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post #25 of 38 Old 12-11-2012, 12:17 PM
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Originally Posted by DonH50 View Post

Think of it this way: You have a 200 W amp driving full-range, providing 200 W total to the speaker (highs and lows). Now, bi-amp, using two 200 W amplifiers. You have a max of 200 W to the bass and 200 W to the highs, exactly the same as you had with a single 200 W amp driving highs and lows. You do not get 400 W into either frequency band. No net power increase to the speaker, you have just split where the power goes into two frequency bands. A 400 W amp is twice the power to the speaker (albeit that is only 3 dB, a pretty modest headroom increase). This is all true for active or passive bi-amping if you use the same size amps. The usual benefits from (active) bi-amping arise from eliminating the passive crossovers in the speakers and optimizing power distribution by e.g. using a much larger (higher-power) amp for the bass than the treble.


I thought Onkyo actually allowed active bi-amping using a crossover in the receiver?

Not how I read the manual. What I see is both sets of power amps in the receiver running across the full audio range. All Onkyo does is route the same audio to the inputs of both amps making up the passive biamp pair.
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Still of arguable benefit in a consumer speaker where the crossovers remain in place.

Don't see it happening that way. You'd have to tell the receiver what the crossover frequency of the speaker was. See no place to set up a say, 3 KHz crossover for a typical 2-way speaker.
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post #26 of 38 Old 12-11-2012, 12:25 PM
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Originally Posted by DonH50 View Post

I thought Onkyo actually allowed active bi-amping using a crossover in the receiver?

Onkyo makes it really easy to bi-amp but my understanding is that it is the same signal to both amps.

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post #27 of 38 Old 12-11-2012, 12:57 PM
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I guess we'll all be making use of our Surr Back/Zone 3 terminals now then, safe in the knowledge that we are not losing SQ? smile.gif
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post #28 of 38 Old 12-11-2012, 03:01 PM
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Nor gaining much, if any.

Just because there is a knob doesn't mean you should turn it.
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post #29 of 38 Old 12-11-2012, 03:14 PM
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Originally Posted by arnyk View Post

The only improvements that matter are the ones that are audible. Power only adds to sound quality if it is needed to avoid audible distortion in the power actually sent to the speakers.
Having a 100 watt amp putting out 10 watts is not necessarily any better sounding than having a 200 watt amp putting out 10 watts, How do you know how much power you are actually using.
Please remind me again about the benefits of driving a car that can go 200 mph on a road where the law enforcement makes it highly inadvisable to go faster than 70.
A 200 watt ( 8 ohm) power amp can only provide about 40 volts of audio to the speaker. 2 200 watt amps each driving part of a speaker (which is what passive biamping does) still can't deliver any more than 40 volts to the speaker. If you want to apply 500 watts to an 8 ohm speaker you need to come up with much more voltage (about 64 volts) than 2 or any number of 200 watt amps can provide.

why does it not deliver 80V?

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post #30 of 38 Old 12-11-2012, 04:07 PM
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Originally Posted by BVLDARI View Post

why does it not deliver 80V?

Easy enough to google ohms law calculators and look at current and voltage required to reach any given power at any given impedance if you are interested.Each speaker output (except the And B that are parallel) has its own power amplifier. So a 7.1 receiver actually contains seven sepate mono amps. IOW, a single monophonic amplifier cannot see, feel, taste or hear that there are multiple speakers attached to it. It can only output the amplified version of whatever signal is sent to it, and cannot send different outputs to different speakers. That requires separate amplifiers with separate inputs and separate outputs. If the amps are each specified to deliver 200 watts, each can only deliver 200 watts cleanly, and you cannot combine them unless you want burning smells to emanate from the receiver.

The main thing, to me, is that if the crossover that biamping hits is between the tweeter and the woofer(s), using actual movie and music signals instead of white noise signals, the tweeter gets at most something like 20 percent of the total power. So if (frankly unlikely except for millisecond peaks) your amp to the low speakers is actually putting out 200 watts, the most the amp to the tweeter would be putting out is 40 watts. A little less than one decibel potential increased SPL. Even if you doubled power, the added SPL is 3 dB. Most folk would call three dB "one notch" louder or quieter.
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