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post #361 of 1044 Old 11-15-2013, 05:50 PM
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Originally Posted by arnyk View Post

Given that one can obtain very clean and robust amps with easily 10 times the power for far less, it seems expensive to me. It appears from this that you may desire to deify bad decision making and wasting money.

I calculated I needed around 160 watts per speaker and didn't need more powerful amps for the job. But nice of you to state your opinion of what you think is expensive or not.

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The above post seems to be a good example how of ignorance and arrogance come together in droves.

The poster above seems to presume that he knows the complete inventory of audio gear that I own and that it is all what he calls "entry level". He also presumes that I despise everybody who owns equipment that is not entry level, even though that is me.
Was your goal all along to have a bi-amped system regardless, or was the goal to have a good sounding audio system?

Didn't you recently get yourself a new AVR? Wasn't it a refurbished lower end Denon? Even though you recognise and recommend to others the advantages of Audyssey XT32 you went for a lower end model without XT32?

I'm certainly not knocking anybody for being on a budget with their audio gear as we all have different priorities in life. But to knock other people that happen to spend more money on their gear than you do in an attempt to feel better about your own decisions is rather sad.


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If your goal was to have a bi-amped system regardless, then it would appear that the entirety of your recent posts to this thread, which seemed to have a veneer of open-mindedness, are a complete and total sham.

Is it then fair to conclude that you have never wanted anything but a passively biamped system, and that your mind has always been utterly and totally closed to less complex and possibly more effective and less costly solutions?

I have always had the idea of trying active bi-amping (example) as it is an upgrade path recommended by my speaker manufacturer. To end up with this destination though I first need bi-wire back to bi-amps. Passive to active was going to be my last step. But apparently it's not going to be worth the hassle so I may just stop with what I have now.
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post #362 of 1044 Old 11-15-2013, 07:30 PM
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Originally Posted by kiwi2 View Post

I calculated I needed around 160 watts per speaker and didn't need more powerful amps for the job. But nice of you to state your opinion of what you think is expensive or not.

Calculating you need 160 watts is one thing, but passive biamp with 2x 80W doesn't give you that regardless of how much or how little you paid.

Just because there is a knob doesn't mean you should turn it.
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post #363 of 1044 Old 11-15-2013, 07:45 PM
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Originally Posted by whoaru99 View Post

Calculating you need 160 watts is one thing, but passive biamp with 2x 80W doesn't give you that regardless of how much or how little you paid.

That was for when it was going to be an active bi-amp system. Active was my ultimate goal. However it is also ticking along just fine now as a passive bi-amp.
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post #364 of 1044 Old 11-16-2013, 06:23 AM
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Originally Posted by kiwi2 View Post

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Originally Posted by arnyk View Post

Given that one can obtain very clean and robust amps with easily 10 times the power for far less, it seems expensive to me. It appears from this that you may desire to deify bad decision making and wasting money.

I calculated I needed around 160 watts per speaker and didn't need more powerful amps for the job. But nice of you to state your opinion of what you think is expensive or not.

Wrong. I stated that I thought that an 80 watt pea shooter for $650 was expensive. I never said what I thought was not expensive.


Quote:
The above post seems to be a good example how of ignorance and arrogance come together in droves.

The poster above seems to presume that he knows the complete inventory of audio gear that I own and that it is all what he calls "entry level". He also presumes that I despise everybody who owns equipment that is not entry level, even though that is me.
Was your goal all along to have a bi-amped system regardless, or was the goal to have a good sounding audio system?

Quote:
Didn't you recently get yourself a new AVR? Wasn't it a refurbished lower end Denon? Even though you recognise and recommend to others the advantages of Audyssey XT32 you went for a lower end model without XT32?

I'm not going to split hairs with such a well-practiced self-appointed critic of all things audio by means of the inspection of price tags. Anybody who thinks that a mid-line Denon is "Entry level" has their head is stuck where the sun shines not.

Like I said your posts demonstrate the mistake that most superficial thinkers make, which is reaching far reaching judgements based on far too little evidence.
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I'm certainly not knocking anybody for being on a budget with their audio gear

Denial isn't a river in Egypt.
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As we all have different priorities in life. But to knock other people that happen to spend more money on their gear than you do in an attempt to feel better about your own decisions is rather sad.

I have never ever done what you said, and unbeknownst to you even I have spent far more money on audio gear than my last few purchases. However people who deify wasting money on underperforming equipment and making bad system upgrade choices deserve the consequences of following their own flawed methodologies.

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Quote:
If your goal was to have a bi-amped system regardless, then it would appear that the entirety of your recent posts to this thread, which seemed to have a veneer of open-mindedness, are a complete and total sham.

Is it then fair to conclude that you have never wanted anything but a passively biamped system, and that your mind has always been utterly and totally closed to less complex and possibly more effective and less costly solutions?

I have always had the idea of trying active bi-amping (example) as it is an upgrade path recommended by my speaker manufacturer. To end up with this destination though I first need bi-wire back to bi-amps. Passive to active was going to be my last step. But apparently it's not going to be worth the hassle so I may just stop with what I have now.

As I earlier observed, denial ain't just a river in Egypt. ;-)
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post #365 of 1044 Old 11-16-2013, 06:25 AM
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Originally Posted by mtn-tech View Post

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Originally Posted by DonH50 View Post


If you have a 100 W amp it delivers 100 W over all frequencies. If you bi-amp with two 100 W amps the LF driver can see up to 100 W and the HF driver can see up to 100 W. If you are passively bi-amping, since both amps have the same voltage output over all frequencies, there is no voltage headrooom added. You have split the output across two amps but essentially no additional power is gained; 100 W to all drivers vs. 100 W to the low driver and 100 W to the high driver, still limited by voltage rails in the amp, each driver sees no more power than before.

- Don

Thank you both! I almost had it with Arny's explanation but with your comment "still limited by voltage rails in the amp" I finally got it. I think that amplifier output power is almost always limited by the voltage of the power supply rails (at clipping) seen across the speaker's impedance. No higher voltage, no more power to the speaker regardless of how many channels are being used.

I guess if the power to a speaker was being limited by current or thermal design (like a really low end amp driving a "difficult" speaker with a very low impedance) there could be an advantage to passive bi-amping (twice the current output or thermal capabilities) but this certainly isn't the case for the average speakers or amplifier. Certainly not for me with my 8 Ohm / 91dB sensitivity speakers and my 2 Ohm capable amps - there would be no gain in voltage and therefore no difference.

You are hitting on all relevant points!
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post #366 of 1044 Old 11-16-2013, 07:06 AM
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Originally Posted by stereoforsale View Post

I will stop biamping (and bi-wiring) and engage a full 9.1 system. If my amps aren't cutting it, then I'll Iook to get a +200W stereo amp for my FL & FR speakers, or perhaps a 3ch amp to drive my center ch too (I want to maintain the same sonic signature across the front soundstage). Anything less than 200w won't make much difference anyway, right? Any recommendations? Max weight ~40lbs and ~16" deep (i.e. Emotiva too big/heavy!)

So I tried going 9.1 and stopped both passive biamping and biwiring... and sorry guys, it sounds worse to me: thin, anemic and metallic. I'm not sure if it the reason is the addition of 2 channels to the same amp, or the single amping, or the single wiring, or a combo of factors. Or it could be the placebo effect (which I guess means I subconsciously want to believe the manufacturers). To be fair, I want to tweak a bit more before I give up on it. Will report back. But frankly, if I was happy with passive biamping before, I will likely go back, and forego 9.1. The lack of published studies (not blogs/forums) probably makes me biased, at least subconsciously. i'd rather have confidence in a 7.1 set up (with passive biamping) vs. having doubts about a non-biamped 9.1 setup smile.gif
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post #367 of 1044 Old 11-16-2013, 07:37 AM
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You are simply reacting to a change in your setup. You haven't compared apples and apples. You would have to compare the identical setup with and without the biamp. If biamplification makes you feel better then by all means do what makes you feel better.
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post #368 of 1044 Old 11-16-2013, 07:50 AM
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Originally Posted by arnyk View Post

Anybody who thinks that a mid-line Denon is "Entry level" has their head is stuck where the sun shines not.
Then you must include the employees of Denon, their reps and dealers where sun does not shine too! They all would absolutely put a few hundred dollar AVR in the entry level bucket. $1000 is roughly the demarcation for the mid-range.
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Like I said your posts demonstrate the mistake that most superficial thinkers make, which is reaching far reaching judgements based on far too little evidence.
Exactly the mistake made when you tried to explain the marketing segmentation names for this category. And why not give him a direct answer? You said he doesn't know what you own but seems like he does with your technique of changing the topic per above.
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I have never ever done what you said, and unbeknownst to you even I have spent far more money on audio gear than my last few purchases.
List them for us please and a picture of your setup.
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As I earlier observed, denial ain't just a river in Egypt. ;-)
Well, we are going to test that by seeing if you list your gear and provide a picture or not smile.gif.

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post #369 of 1044 Old 11-16-2013, 08:00 AM
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One of the benefits of bi-amping is that when the amp driving the bass distorts, its harmonic distortion does not travel to the tweeter as it would in a single amp set-up. Since the low frequencies have the most energy, it is likely that amp would distort. If harmonics land beyond the crossover frequency of the woofer, then simply get thrown away. Let's say your crossover is 1K. Harmonics of 800 Hz would be at 1.6 Khz, 2.4 Khz, etc. The first one may get through a bit depending on the slope of crossover but the later ones would be hugely attenuated in bi-amp situation. With a single amp, those would be happily played by the tweeter. Since high frequencies in music are at much lower level, the harmonic distortions of the low frequencies get to play a larger role there. This is why when you compress difficult content, it can sound brighter/harsher at times. Same thing happens here.

Here is a cool picture showing the typical spectrum differences:

rascricket.png

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post #370 of 1044 Old 11-16-2013, 08:03 AM
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Quote:
Originally Posted by amirm View Post

Quote:
Originally Posted by arnyk View Post

Anybody who thinks that a mid-line Denon is "Entry level" has their head is stuck where the sun shines not.
Then you must include the employees of Denon, their reps and dealers where sun does not shine too! They all would absolutely put a few hundred dollar AVR in the entry level bucket. $1000 is roughly the demarcation for the mid-range.

Amir I can count on you to present evidence from the most highly biased of all sources as revealed global truth! ;-)

You probably think that the whole world is like norhheast Washington state! ;-)
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Quote:
Like I said your posts demonstrate the mistake that most superficial thinkers make, which is reaching far reaching judgements based on far too little evidence.
Exactly the mistake made when you tried to explain the marketing segmentation names for this category. And why not give him a direct answer? You said he doesn't know what you own but seems like he does with your technique of changing the topic per above.

Had I actually made a mistake Amir you would be able to say what it was and document how it was a mistake. Seeing neither...
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I have never ever done what you said, and unbeknownst to you even I have spent far more money on audio gear than my last few purchases.
List them for us please and a picture of your setup.

Amir I've been buying audio gear since 1961, and not even I can list everything I've ever bought in that time frame.
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As I earlier observed, denial ain't just a river in Egypt. ;-)
Well, we are going to test that by seeing if you list your gear and provide a picture or not smile.gif.
[/quote]

Amir are you trying to distract us from what a disaster your last photograph of borrowed equipment was? ;-)

Anybody with trade contacts and a digital camera or cheap cell phone can create whatever fantasy they wish to...
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post #371 of 1044 Old 11-16-2013, 08:13 AM
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Originally Posted by arnyk View Post

Amir I can count on you to present evidence from the most highly biased of all sources as revealed global truth! ;-)

You probably think that the whole world is like norhheast Washington state! ;-)
I live on the west coast of Washington state, not east. Do you not know where Seattle is???

I have to imagine that you think when I speak to Denon here, they would position their AVRs as entry levels but when they go to New York they tell the retailer it is mid-level. Is that what you are saying?
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Amir I've been buying audio gear since 1961, and not even I can list everything I've ever bought in that time frame.
Denial is not just a river in Egypt Arny. We like to know what you have now and a picture. You are not ashamed of giving us that info, are you?
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Amir are you trying to distract us from what a disaster your last photograph of borrowed equipment was? ;-)
Which disaster Arny? While we wait for that answer, you see how transparent I am with presenting pictures and details of my gear. Just asking for same transparency from you lest you think we turn that into a disaster wink.gif.
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Anybody with trade contacts and a digital camera or cheap cell phone can create whatever fantasy they wish to...
We assume you are trustworthy and would not do so. Please present a picture for us. If it is fake, the damage will be on us, not you.

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post #372 of 1044 Old 11-16-2013, 08:25 AM
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Guys does this analogy make sense: imagine a car @ 5000rpm going 100km/h with a given wind resistance. Adding a second car @5000 rpm won't add anything, they both still go 100km/hr. But what I gather from Anthem is that biamping effectively, and significantly, reduces the wind resistance on the cars (i.e. increases the ohms seen by each amp) and therefore both cars can now go faster @ 5000 rpm. The fully amplified signal going to the tweeter has no resistance on the bass frequencies, and vice versa. Increase the apparent ohms, reduce the resistance, and get more output per watt. Isn't it just that simple? confused.gif Just a novice's view of it smile.gif
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post #373 of 1044 Old 11-16-2013, 09:06 AM
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Guys does this analogy make sense
No.

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post #374 of 1044 Old 11-16-2013, 03:21 PM
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Originally Posted by amirm View Post

Then you must include the employees of Denon, their reps and dealers where sun does not shine too! They all would absolutely put a few hundred dollar AVR in the entry level bucket. $1000 is roughly the demarcation for the mid-range. ....

Please share with us the results of the survey you did with Denon employees, their reps and dealers. What questions were asked? Did you ask all employees or do random sampling? If random, how were they chosen?
Thanks in advance.

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post #375 of 1044 Old 11-16-2013, 03:23 PM
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Originally Posted by amirm View Post

One of the benefits of bi-amping is that when the amp driving the bass distorts, its harmonic distortion does not travel to the tweeter as it would in a single amp set-up. Since the low frequencies have the most energy, it is likely that amp would distort. If harmonics land beyond the crossover frequency of the woofer, then simply get thrown away. Let's say your crossover is 1K. Harmonics of 800 Hz would be at 1.6 Khz, 2.4 Khz, etc. The first one may get through a bit depending on the slope of crossover but the later ones would be hugely attenuated in bi-amp situation. With a single amp, those would be happily played by the tweeter. Since high frequencies in music are at much lower level, the harmonic distortions of the low frequencies get to play a larger role there. This is why when you compress difficult content, it can sound brighter/harsher at times. Same thing happens here.

Here is a cool picture showing the typical spectrum differences:

...

I bolded, italicized, and underlined part of your post, because it's a critical phrase. Now, when does the amp driving the bass distort? Is that something that happens in many cases?

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post #376 of 1044 Old 11-16-2013, 03:47 PM
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If the bass amp is distorting due to exceeding supply rails, in a passive bi-amp system the tweeter amp is clipping at the same time due to the large bass signal even though it is not putting out significant power at the lower frequency.
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post #377 of 1044 Old 11-16-2013, 04:06 PM
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Originally Posted by DonH50 View Post

If the bass amp is distorting due to exceeding supply rails, in a passive bi-amp system the tweeter amp is clipping at the same time due to the large bass signal even though it is not putting out significant power at the lower frequency.

Depends on whether we're talking about bi-amping in, say, an AVR, versus bi-amping with something like two completely separate amps, no?

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post #378 of 1044 Old 11-16-2013, 04:33 PM
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Originally Posted by UndersAVS
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Exhibit A: amps are presented with the incoming signal; the signal is amplified; amps deliver power to speaker according to the incoming signal. Power required of each channel is the same. (concurring with the potential power loss in the all channels driven example).

Exhibit B: amps are presented with the incoming signal, the signal is amplified, amps deliver power to speaker according to the load presented by the speaker's crossover. Power to each channel may vary.

QUOTE]

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Originally Posted by whoaru99 View Post

No, neither.

It comes down to voltage swing into the speakers. Regardless if you use one 100w amp or two 100w amps in passive biamp the voltage presented to the speaker is the same in either case, and the crossover passes the signal on through to the drivers the same in either case. So, no net power increase, no net SPL increase.

If you read each of my previous comments, I didn't indicate that net power or SPL is increased. Perhaps my wording was poor, but that is the point I tried to communicate in the first example, exhibit A. Each amp in passive biamp configs is tasked with the full frequency range (bandwidth).
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Going back to the simplified example using power, say 100w amp split 75w/25w LF to HF, the point that sticks most people is they assume because you're using only 75w of the LF amp and only 25w of the HF amp that you have more headroom or more power in reserve. But, you don't, because the amps are still swinging voltage for the full range signal. Thus, clipping point isn't increased for either amp and the "missing" power can't be used elsewhere because it's tied up in the out of band component of the full range voltage swing.

Fully agree. However, none of my comments indicated that headroom is increased or that more power is in reserve. In fact, I pointed to an example where potential loss of current is available to the speaker when using the multi-channel Receiver biamp feature, where the Receiver's rear amps and front amps are used to power front speakers..

Given your explanation, it seems that you agree with my previous suggestion that audio quality could suffer when using the biamp feature in AV Receivers that deliver less current when more than two channels are driven. Biamping with these AVR's reduces the potential current available to the two speakers. In this scenario, potential current is decreased when four amps are employed to power the speaker, rather than two, The four amps are more susceptible to clipping in this scenario.
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post #379 of 1044 Old 11-16-2013, 04:43 PM
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*Newform Research* speakers. *NuForce* amps. Different companies.

Ever heard the description "beet red?" I think that would describe the color of my face when reading your post ;~D
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post #380 of 1044 Old 11-16-2013, 05:28 PM
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Originally Posted by amirm View Post

One of the benefits of bi-amping is that when the amp driving the bass distorts, its harmonic distortion does not travel to the tweeter as it would in a single amp set-up. Since the low frequencies have the most energy, it is likely that amp would distort. If harmonics land beyond the crossover frequency of the woofer, then simply get thrown away. Let's say your crossover is 1K. Harmonics of 800 Hz would be at 1.6 Khz, 2.4 Khz, etc. The first one may get through a bit depending on the slope of crossover but the later ones would be hugely attenuated in bi-amp situation. With a single amp, those would be happily played by the tweeter. Since high frequencies in music are at much lower level, the harmonic distortions of the low frequencies get to play a larger role there. This is why when you compress difficult content, it can sound brighter/harsher at times. Same thing happens here.

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Originally Posted by beaveav View Post

Please share with us the results of the survey you did with Denon employees, their reps and dealers. What questions were asked? Did you ask all employees or do random sampling? If random, how were they chosen?
Thanks in advance.

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Originally Posted by beaveav View Post

I bolded, italicized, and underlined part of your post, because it's a critical phrase. Now, when does the amp driving the bass distort? Is that something that happens in many cases?

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Originally Posted by DonH50 View Post

If the bass amp is distorting due to exceeding supply rails, in a passive bi-amp system the tweeter amp is clipping at the same time due to the large bass signal even though it is not putting out significant power at the lower frequency.

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Originally Posted by beaveav View Post

Depends on whether we're talking about bi-amping in, say, an AVR, versus bi-amping with something like two completely separate amps, no?


The more significant point in my mind, though harmonic distortion is minimized across the bandwidth when using seperate amps for biamping, as opposed to a Receiver, you're still left with audible distortion. Who wants that?
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post #381 of 1044 Old 11-16-2013, 05:57 PM
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Originally Posted by UndersAVS View Post

Originally Posted by UndersAVS


Fully agree. However, none of my comments indicated that headroom is increased or that more power is in reserve. In fact, I pointed to an example where potential loss of current is available to the speaker when using the multi-channel Receiver biamp feature, where the Receiver's rear amps and front amps are used to power front speakers..

Given your explanation, it seems that you agree with my previous suggestion that audio quality could suffer when using the biamp feature in AV Receivers that deliver less current when more than two channels are driven. Biamping with these AVR's reduces the potential current available to the two speakers. In this scenario, potential current is decreased when four amps are employed to power the speaker, rather than two, The four amps are more susceptible to clipping in this scenario.

No, I don't agree, and you did mention SPL.

In a multichannel receiver the load/current demand on the power supply neither increases nor decreases when biamping, because no more nor no less power is delivered to the speakers.

Just because there is a knob doesn't mean you should turn it.
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post #382 of 1044 Old 11-16-2013, 06:54 PM
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Originally Posted by DonH50 View Post

If the bass amp is distorting due to exceeding supply rails, in a passive bi-amp system the tweeter amp is clipping at the same time due to the large bass signal even though it is not putting out significant power at the lower frequency.

Depends on whether we're talking about bi-amping in, say, an AVR, versus bi-amping with something like two completely separate amps, no?

True in any passive biamp system where the power amps have the same input sensitivity. AVR or stand-alone power amp, matters not.

This discussion appears to have gotten got kinda derailed because we suffered a post from someone who either doesn't know the difference between passive and active biamping, or never bothered to find out that the thread was primarily about passive biamping. He confused things further by not prefacing his comments, which applied only to only active biamping, with active.
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post #383 of 1044 Old 11-16-2013, 07:03 PM
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Originally Posted by whoaru99 View Post

No, I don't agree, and you did mention SPL.

I mentioned SPL, but never stated that passive biamping increases SPL.
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In a multichannel receiver the load/current demand on the power supply neither increases nor decreases when biamping, because no more nor no less power is delivered to the speakers

I'm confused by your reasoning. Given that the biamped M/C Receiver must power four amps with the full frequency band, rather than two, why does the power supply load remain the same?
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post #384 of 1044 Old 11-16-2013, 07:33 PM
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Originally Posted by UndersAVS View Post

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Originally Posted by whoaru99 View Post

No, I don't agree, and you did mention SPL.

I mentioned SPL, but never stated that passive biamping increases SPL.
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In a multichannel receiver the load/current demand on the power supply neither increases nor decreases when biamping, because no more nor no less power is delivered to the speakers

I'm confused by your reasoning. Given that the biamped M/C Receiver must power four amps with the full frequency band, rather than two, why does the power supply load remain the same?

It doesn't stay exactly the same because amplifier efficiency varies with output. However, estimating that it remains the same is a good first estimate.

This is a plot of the efficiency of a typical 150 class AB power amp versus output:



The amp's efficiency is 65% from the chart at 150 watts output, which means that it draws about 230 watts from its power supply when supplying 150 watts to the speakers.

If we split the 150 watts up equally among two amps, their efficiency from the chart at 75 watts output each drops dramatically to 45%, so each amp draws 166.7 watts for 333.3 watts total. 333 watts > 230 watts and not by just a little bit!

In this case if the passive biamping splits the power equally between the two amps, it would put greater stress on its power supply and is possible it may even somewhat decrease the actual maximum power available, total. This is because passive biamping tend to significantly decrease the efficiency of the power amp. Class AB power amps are most efficient near full output and passive biamping reduces power output per channel.
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post #385 of 1044 Old 11-17-2013, 06:04 AM
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Quote:
Originally Posted by UndersAVS View Post

I mentioned SPL, but never stated that passive biamping increases SPL.
I'm confused by your reasoning. Given that the biamped M/C Receiver must power four amps with the full frequency band, rather than two, why does the power supply load remain the same?

My reason is that just becase an amp has to swing voltage doesn't mean it's a big burden on the power supply. I can crank the output of an amp to clipping, but with no load it doesn't draw much power. The crossover HPF/LPF presents higher impedance to out of band signal thus while voltage still swings full range, high impedance out of band means less current, thus less power.

That said, Arny has provided an interesting aspect for consideration. I detect an experiment in my future, although it will be at least a week since a business trip is imminent, as in plane leaving 3pm today and I have to leave about 4 hours before then.

Just because there is a knob doesn't mean you should turn it.
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post #386 of 1044 Old 11-17-2013, 07:14 AM
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Quote:
Originally Posted by beaveav View Post

Quote:
Originally Posted by DonH50 View Post

If the bass amp is distorting due to exceeding supply rails, in a passive bi-amp system the tweeter amp is clipping at the same time due to the large bass signal even though it is not putting out significant power at the lower frequency.

Depends on whether we're talking about bi-amping in, say, an AVR, versus bi-amping with something like two completely separate amps, no?

If you have two independent but identical amplifiers driven by the same input signal they will clip the same essentially independent of the load. The situation is the same for two amplifiers in separate boxes or two channels in an AVR. Yes, the independent amps do not share a power supply so may deliver a little more power (see below), but i would expect that difference to be slight (maybe 1 dB or so) at max rated power. IME experience load dependence on the performance of SS amps is minimal unless you go to extremes, and by that I do not mean the speakers 99.999% or whatever of us are using.

The big caveat is AVRs that have weak enough power supplies so that multichannel operation degrades power significantly. Of the 5 or 6 AVRs of different brands that I have in the house, acquired over maybe 20+ years, that is only true of one of them. Even then the only time you might notice is at max volume, louder than I can stand anyway.

If you use an external line-level crossover before the two separate amps to create an active bi-amp system the situation is entirely different, of course.

The general way these arguments go is that, even though the vast majority will see (hear) none of the theoretical benefits of passive bi-amping, everybody is convinced they are The One. I was the same back when I got into this business (late 60's/early 70's), working for a high end store and fully convinced I could hear every nuance in swapping amps, cables, adding rubber feet, etc., but a lot of engineering and numerous tests (blind, double-blind, ABX, etc. in addition to gobs of measuring components) slapped some sense in me despite my beliefs. That said, there was truth in some of the claims, but compared to the wealth of disinformation and hyperbole it was slight. I was shocked and annoyed but have survived despite all that.

FWIWFM - Don

Edit: I do not know if I am the guilty party Arny mentioned that wsa comparing active and passive bi-amping, My apologies if so. I had not heard of passive bi-amping as implemented by AVRs until just a few years ago. Bi-amping to me always implied a crossover before the power amps, either an active crossover using transistors or tubes, or a passive RLC box, but either one operated at line level. I simply never thought of driving both amps with the same signal, seems like such a waste.

"After silence, that which best expresses the inexpressible, is music" - Aldous Huxley
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post #387 of 1044 Old 11-17-2013, 01:18 PM
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Originally Posted by DonH50 View Post

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Originally Posted by beaveav View Post

.

The big caveat is AVRs that have weak enough power supplies so that multichannel operation degrades power significantly. Of the 5 or 6 AVRs of different brands that I have in the house, acquired over maybe 20+ years, that is only true of one of them. Even then the only time you might notice is at max volume, louder than I can stand anyway.

The power supplies in AVRs are generally adequate for handling music with its high crest factor. The tests showing a lack of power are always done with pure sine waves that have a far lower crest factor.

BTW, Don, my comment about active/passive biamping confusion was not about you.

Like you biamping has been synonymous to me with active biamping most of my life.
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post #388 of 1044 Old 11-17-2013, 03:21 PM
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Originally Posted by arnyk View Post

True in any passive biamp system where the power amps have the same input sensitivity. AVR or stand-alone power amp, matters not.

This discussion appears to have gotten got kinda derailed because we suffered a post from someone who either doesn't know the difference between passive and active biamping, or never bothered to find out that the thread was primarily about passive biamping. He confused things further by not prefacing his comments, which applied only to only active biamping, with active.

I rolled over in bed at 1AM last night and suddenly the thought popped into my head that my post was all wrong. I couldn't sleep half the night after that. Reminded me of when I was in college and would realize I had done a homework problem wrong after I'd just turned in my work.

I was thinking of an active system but didn't say so. I was speed-reading through this thread and, quite honestly, shouldn't have posted without first reading more carefully. So my post was garbage and just furthered the miscommunication in this thread. I apologize for the post, and Don and Arny, you're right.

For every new thing I learn, I forget two things I used to know.
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post #389 of 1044 Old 11-17-2013, 05:13 PM
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@Arny: Yes, duh, I meant to add a note about musical crest factors vs. sine-wave testing but spaced it. What I get for trying to type whilst oiling my valves for rehearsal... Thanks for your insights!

@beaveav: NP. The first time I entered a passive bi-amping thread I assumed they were talking about a passive line-level crossover. Confusion reigned.

"After silence, that which best expresses the inexpressible, is music" - Aldous Huxley
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post #390 of 1044 Old 11-17-2013, 06:30 PM
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Originally Posted by mcnarus View Post

No.

Ok, another thought. The speaker's internal crossover blocks the unused part of the signal, hence there isn't a complete circuit at those unwanted frequencies, and therefore that part of the signal is simply not part of the signal sent to the speaker: no circuit = no current (at the blocked frequencies). The part of the signal that is blocked by the internal crossover is never amplified and never leaves the amp since there is no where for it to go (no circuit). So the only signal going to the HF post is HF signal, and the only signal going to the LF post is the LF signal. Yes? No? smile.gif
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