Bi-Wiring/Bi-Amping With Onkyo 605...Viable? - Page 4 - AVS Forum
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post #91 of 214 Old 11-27-2013, 12:33 PM
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Originally Posted by jneutron View Post

Is your load purely resistive, or will it also exercise all four output quadrants? I could see a difference using passive bi-amping if the combined loads engaged an output stage foldback protection. But I'd not expect a difference if there is no foldback.

My test will use resistive loads to keep things simple.
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Output stage foldback protection can be activated by both resistive and reactive loads.

This is an example of that
:
http://theaudiocritic.com/plog/index.php?op=ViewArticle&articleId=22

$200 amplifier



http://theaudiocritic.com/plog/index.php?op=ViewArticle&articleId=5&blogId=1

$2,000 amplifier



http://www.audiograph.se/Downloads/PowerCube_12p_brochure_complete.pdf
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post #92 of 214 Old 11-27-2013, 12:53 PM
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Originally Posted by arnyk View Post

My test will use resistive loads to keep things simple.

I like simple as long as the simplicity doesn't overlook anything.

The only issue I can see is one of reactive loads. When the loads are reactive and there are three branches at the crossover, the mid and high content currents may invoke foldback protection even though the composite signal does not exceed rails. Using pure resistive loads does not guarantee seeing that.

If you could toss even some bog standard inductors consistent with actual speakers into the resistive loads, then you may be able to find the foldback limit occurring when all two or three loads are on one amp, vs bass in one and mid/highs in another.

To sum it up...using pure resistive loads after the crossover may not be consistent with what happens with real speakers. Just a caution.

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post #93 of 214 Old 11-27-2013, 12:59 PM
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Originally Posted by jneutron View Post

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Originally Posted by arnyk View Post

My test will use resistive loads to keep things simple.

I like simple as long as the simplicity doesn't overlook anything.

Engineering is all about knowing what to overlook.
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The only issue I can see is one of reactive loads. When the loads are reactive and there are three branches at the crossover, the mid and high content currents may invoke foldback protection even though the composite signal does not exceed rails. Using pure resistive loads does not guarantee seeing that.

Agreed, but please know that you are preaching to the choir.
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If you could toss even some bog standard inductors consistent with actual speakers into the resistive loads, then you may be able to find the foldback limit occurring when all two or three loads are on one amp, vs bass in one and mid/highs in another.

To sum it up...using pure resistive loads after the crossover may not be consistent with what happens with real speakers. Just a caution.

I have a speaker simulator that is about twice as aggressive as the one used by a well-known golden eared magazine editor. I might give it a spin after I get some results and still have working equipment to play with.
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post #94 of 214 Old 11-27-2013, 01:07 PM
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Originally Posted by arnyk View Post

I have a speaker simulator that is about twice as aggressive as the one used by a well-known golden eared magazine editor. I might give it a spin after I get some results and still have working equipment to play with.

Is your simulator capable of testing single amp, and then splitting it to test passive biamp?

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post #95 of 214 Old 11-27-2013, 01:28 PM
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Originally Posted by jneutron View Post

Quote:
Originally Posted by arnyk View Post

I have a speaker simulator that is about twice as aggressive as the one used by a well-known golden eared magazine editor. I might give it a spin after I get some results and still have working equipment to play with.

Is your simulator capable of testing single amp, and then splitting it to test passive biamp?

jn

yes.
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post #96 of 214 Old 11-27-2013, 02:05 PM
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Excellent. Then all you have to do is run the full load until you start to get distortion, either some test signal, noise, or heaven forbid, Zepplin "heartbreaker". Once you see the distortion of the midband content, disconnect the simulated woofer part of the load.

If the midband content distortion drops, then passive biamping worked.

Music may be too difficult. Perhaps a 20 hz, 550 hz, and a 3 K signal mixed together at some appropriate ratio simulating music. Look at the 550 and 3K harmonics, then disconnect the lf load. Any three freq's will do as long as the fft can distinguish the distortion products of the midband content from the distortions of the lf signal.

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post #97 of 214 Old 11-27-2013, 06:47 PM - Thread Starter
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Wow. Utterly incredible. This thread spirals into a technological prowess match to the death (to me, this "Arnold" is truly something else...) and I'm being told my questions have been answered already? All I know is I am going around in proverbial circles here when all I wanted to know was if what I was suggesting in the original post was to yield any discernable differences in sound quality in people's opinions -- then, siva claims that originally what I was asking was technical and now he's claiming "it ain't rocket science"...

Whew. I'm done here; I took this to a PM foray to communicate with Jason on a one-on-one, more civil basis because the scientific manhood waving is just getting too much in this thread. Thanks to everyone who contributed in a more gentle-hearted, down-to-earth manner.

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post #98 of 214 Old 11-27-2013, 07:12 PM
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Originally Posted by jneutron View Post

Excellent. Then all you have to do is run the full load until you start to get distortion, either some test signal, noise, or heaven forbid, Zepplin "heartbreaker". Once you see the distortion of the midband content, disconnect the simulated woofer part of the load.

If the midband content distortion drops, then passive biamping worked.

Wrong. the drop has to be large enough and of a kind that is audibly significant.

Remember, we are in the world of modern measurements with more decimal places of numbers than we can ever make practical use of.

In this world I can easily and reliably measure the attenuation of a few inches of interconnect.

I can pound the table and see piezoelectric/triboelectric effects of the insulation on a fair percentage of shielded cables.

We are back to the fact that a goodly part of engineering is ignoring irrelevant evidence.

When I'm playing with wannabe golden ears I have to keep reminding them that the golden ear dictum that any difference no matter how microscopic is massively significant just isn't true.;-)
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post #99 of 214 Old 11-27-2013, 07:14 PM
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Wow. Utterly incredible. This thread spirals into a technological prowess match to the death (to me, this "Arnold" is truly something else...) and I'm being told my questions have been answered already?
There is an unsettled technical question here, but it's not the question you asked. The question you asked was, would biamping benefit my situation? And the answer is, certainly not, unless you are experiencing audible levels of distortion from your amp (which you make no mention of and are most unlikely to), and not necessarily even then.

If you can't explain how it works, you can't say it doesn't.—The High-End Creed

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post #100 of 214 Old 11-27-2013, 07:16 PM
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Originally Posted by IntelliVolume View Post

Wow. Utterly incredible. This thread spirals into a technological prowess match to the death (to me, this "Arnold" is truly something else...) and I'm being told my questions have been answered already? All I know is I am going around in proverbial circles here when all I wanted to know was if what I was suggesting in the original post was to yield any discernable differences in sound quality in people's opinions -- then, siva claims that originally what I was asking was technical and now he's claiming "it ain't rocket science"...

Whew. I'm done here; I took this to a PM foray to communicate with Jason on a one-on-one, more civil basis because the scientific manhood waving is just getting too much in this thread. Thanks to everyone who contributed in a more gentle-hearted, down-to-earth manner.

So the "kinder and gentler" advocate gets into audio technology apparently over his head and leaves spewing insults and name calling in all directions...;-)
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post #101 of 214 Old 11-27-2013, 10:35 PM
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Originally Posted by IntelliVolume View Post

Wow. Utterly incredible. This thread spirals into a technological prowess match to the death (to me, this "Arnold" is truly something else...) and I'm being told my questions have been answered already? All I know is I am going around in proverbial circles here when all I wanted to know was if what I was suggesting in the original post was to yield any discernable differences in sound quality in people's opinions -- then, siva claims that originally what I was asking was technical and now he's claiming "it ain't rocket science"...

Whew. I'm done here; I took this to a PM foray to communicate with Jason on a one-on-one, more civil basis because the scientific manhood waving is just getting too much in this thread. Thanks to everyone who contributed in a more gentle-hearted, down-to-earth manner.

i understand your frustrations, and glad i am able to help you. i know sometimes the technical issues can get way over some of our average joe heads.....but i feel that there is merit behind many of these types of discussions. and i don't think it is wise to completely dismiss them....even if they are beyond our understanding. at least for me, it helps me learn and understand many of the concepts involved.

personally i give kudos to guys like arny, a mcnarus and jnuetron and fmw and several others for their willingness to share good technical knowledge gained over years of practical experience. I am wary of grandstanders and hand waivers though.
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post #102 of 214 Old 11-28-2013, 06:08 AM
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i understand your frustrations, and glad i am able to help you. i know sometimes the technical issues can get way over some of our average joe heads.....but i feel that there is merit behind many of these types of discussions. and i don't think it is wise to completely dismiss them....even if they are beyond our understanding. at least for me, it helps me learn and understand many of the concepts involved.

personally i give kudos to guys like arny, a mcnarus and jnuetron and fmw and several others for their willingness to share good technical knowledge gained over years of practical experience. I am wary of grandstanders and hand waivers though.
Maybe it helps OP if you summarized what you have learned however you would communicate it to him in PM. I am sure there are many who read these threads and can benefit from such simple to understand conclusions.

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post #103 of 214 Old 11-28-2013, 06:12 AM
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i understand your frustrations, and glad i am able to help you. i know sometimes the technical issues can get way over some of our average joe heads.....but i feel that there is merit behind many of these types of discussions. and i don't think it is wise to completely dismiss them....even if they are beyond our understanding. at least for me, it helps me learn and understand many of the concepts involved.

personally i give kudos to guys like arny, a mcnarus and jnuetron and fmw and several others for their willingness to share good technical knowledge gained over years of practical experience. I am wary of grandstanders and hand waivers though.
Maybe it helps OP if you summarized what you have learned however you would communicate it to him in PM. I am sure there are many who read these threads and can benefit from such simple to understand conclusions.

nah....im just going to go ahead an punt this for now. smile.gif

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post #104 of 214 Old 11-28-2013, 06:16 AM
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nah....im just going to go ahead an punt this for now. smile.gif
You are a smart man. biggrin.gif

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post #105 of 214 Old 12-02-2013, 06:40 AM
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Wrong. the drop has to be large enough and of a kind that is audibly significant.

You clearly did not understand what was stated. I am not speaking about an IR drop. Go back and re-read.
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Remember, we are in the world of modern measurements with more decimal places of numbers than we can ever make practical use of.
I live in a world of 10 decimal place equipment, and 17 decimal place measurements. Your statement has no contextual meaning to the discussion.
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In this world I can easily and reliably measure the attenuation of a few inches of interconnect.
Wonderful. I measure sub nano-ohm solder joints on superconducting wires. And again, of no contextual relevance.
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We are back to the fact that a goodly part of engineering is ignoring irrelevant evidence.
Which is why it is important for you to go back and understand my post.

While it's great to post graphs from work of others, if you do not understand how it applies to the problem at hand, then you have served no viable purpose.
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When I'm playing with wannabe golden ears I have to keep reminding them that the golden ear dictum that any difference no matter how microscopic is massively significant just isn't true.;-)
So then it's a good thing I'm not a wannabe golden ear, no?

jn

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post #106 of 214 Old 12-02-2013, 06:49 AM
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Originally Posted by mcnarus View Post

There is an unsettled technical question here, but it's not the question you asked. The question you asked was, would biamping benefit my situation? And the answer is, certainly not, unless you are experiencing audible levels of distortion from your amp (which you make no mention of and are most unlikely to), and not necessarily even then.

Hey there, long time. Hope all is well with you.

I've hilited your caveat. In principle, quite correct. However, there are concerns.

If you examine the output graphs ak provided, examine the phase axis and it's relationship to power at any impedance. When the load is reactive and the amp cannot handle that, the power level will drop as phase deviates from zero. The flatness along the phase axis is a good indication that the amp can provide both the voltage and the current required for whatever load the box simulates, and as long as speakers are less reactive than that load, then all is well.

The basic issue as I had pointed out to arny is, what will the amp do to the mids and highs as the voltage swing of the bass brings the channel closer to rails and closer to current max? If the amp does not behave well, one consequence is an increase in mids/highs distortion as a result of the amp's current swing....the output of the amplifier traversing quadrants 2 and 4 as a consequence of a large bass driven into a reactive cabinet while simultaneously trying to control other drivers in parallel at higher frequencies.

In addition, I do not believe the industry is yet at the level of understanding where they can actually perform damping value measurements of mid and highband frequencies with and without a large bass voltage and current present.

jn

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post #107 of 214 Old 12-02-2013, 09:05 AM
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Originally Posted by jneutron View Post

If you examine the output graphs ak provided, examine the phase axis and it's relationship to power at any impedance. When the load is reactive and the amp cannot handle that, the power level will drop as phase deviates from zero. The flatness along the phase axis is a good indication that the amp can provide both the voltage and the current required for whatever load the box simulates, and as long as speakers are less reactive than that load, then all is well.

It has been observed that large phase angles and low impedances tend to not be found together in real world loudspeaker impedance curves.
Quote:
The basic issue as I had pointed out to arny is, what will the amp do to the mids and highs as the voltage swing of the bass brings the channel closer to rails and closer to current max? If the amp does not behave well, one consequence is an increase in mids/highs distortion as a result of the amp's current swing....the output of the amplifier traversing quadrants 2 and 4 as a consequence of a large bass driven into a reactive cabinet while simultaneously trying to control other drivers in parallel at higher frequencies.


It has been observed that just because the Crown DC300 and Phase Linear 700 (late 1960s) had problems with reactive loads has little bearing on life in Y2K.
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In addition, I do not believe the industry is yet at the level of understanding where they can actually perform damping value measurements of mid and highband frequencies with and without a large bass voltage and current present.

Two words: Spectrum analyzer.

BTW "Damping Factor" is old school terminology. Preferred is: Source Impedance.
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post #108 of 214 Old 12-02-2013, 10:22 AM
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Originally Posted by arnyk View Post

It has been observed that large phase angles and low impedances tend to not be found together in real world loudspeaker impedance curves.
A hedged statement not based in facts. You still do not understand what I've stated. Please re-read it.

Also, you paste the test results of the work of others where that very thing is tested, then say it doesn't happen.. Pretty disingenuous.
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It has been observed that just because the Crown DC300 and Phase Linear 700 (late 1960s) had problems with reactive loads has little bearing on life in Y2K.
As I said, you still have no idea what I am speaking of.
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Originally Posted by arnyk View Post

Two words: Spectrum analyzer.
As opposed to my post where I stated the use of the FFT? Please read and understand my posts before you respond..
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BTW "Damping Factor" is old school terminology. Preferred is: Source Impedance.
I've been trying to get you to understand new school concepts, but that isn't working, is it?

The gist of the discussion is this: how does the 1khz source impedance change as the amplifier output traverses all 4 quadrants vs one quadrant operation.

If you still don't understand this concept, please ask questions.

jn
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post #109 of 214 Old 12-02-2013, 11:38 AM
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Originally Posted by jneutron View Post

Quote:
Originally Posted by arnyk View Post

It has been observed that large phase angles and low impedances tend to not be found together in real world loudspeaker impedance curves.
A hedged statement not based in facts. You still do not understand what I've stated. Please re-read it.

Also, you paste the test results of the work of others where that very thing is tested, then say it doesn't happen.. Pretty disingenuous.
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It has been observed that just because the Crown DC300 and Phase Linear 700 (late 1960s) had problems with reactive loads has little bearing on life in Y2K.
As I said, you still have no idea what I am speaking of.
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Originally Posted by arnyk View Post

Two words: Spectrum analyzer.
As opposed to my post where I stated the use of the FFT? Please read and understand my posts before you respond..
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Originally Posted by arnyk View Post

BTW "Damping Factor" is old school terminology. Preferred is: Source Impedance.
I've been trying to get you to understand new school concepts, but that isn't working, is it?

The gist of the discussion is this: how does the 1khz source impedance change as the amplifier output traverses all 4 quadrants vs one quadrant operation.

If you still don't understand this concept, please ask questions.

jn

The short answer is that as long as the amplifier is not outside its linear region of operation, its performance for small changes remains the same.

In the interest of not returning foul for foul, I won't mention that this is about 200 level electrical engineering, if memory serves. ;-)
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post #110 of 214 Old 12-02-2013, 12:01 PM
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The short answer is that as long as the amplifier is not outside its linear region of operation, its performance for small changes remains the same.

As the graphs you pasted from the work of others shows, the output capability at various impedances and various phases changes. Yet, you've described no methodology to test what the removal of the lf load to a marginally distorting signal would be, nor how the phase/timing response of the system would change once operation is removed from a reactive quadrant.

Removing the low frequency driver load from an amplifier which driving seriously into all 4 quadrants is considered "small changes". Even though the bass content is the bulk of the power? Not even a good try there...

So, in other words, you've really no intention of performing a real test..That's fine with me, but you are the one claiming that a test will prove something.
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In the interest of not returning foul for foul, I won't mention that this is about 200 level electrical engineering, if memory serves. ;-)

That depend on what university you went to. Mine used a different numbering scheme.

But you still do not understand the issue, diverting instead.

Try the test as detailed.

jn

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post #111 of 214 Old 12-02-2013, 12:20 PM
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The short answer is that as long as the amplifier is not outside its linear region of operation, its performance for small changes remains the same.

As the graphs you pasted from the work of others shows, the output capability at various impedances and various phases changes

Of course, but that is always true and does not inhibit measuring amplifier source impedance over a useful operational range,
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. Yet, you've described no methodology to test what the removal of the lf load to a marginally distorting signal would be, nor how the phase/timing response of the system would change once operation is removed from a reactive quadrant.

Impedance is generally thought to be a small signal parameter, and small signal parameters presume a linear system. Therefore the phrase "marginally distorting" is irrelevant to this discussion. Back to EGR 200...

Quote:
Removing the low frequency driver load from an amplifier which driving seriously into all 4 quadrants is considered "small changes". Even though the bass content is the bulk of the power?

True as long as the amplifier is operating in its linear region.
Quote:
Not even a good try there...

So, in other words, you've really no intention of performing a real test..That's fine with me, but you are the one claiming that a test will prove something.

Since you claim to be self-sufficient in this area, I'll give you the same offer as I gave Amir. If you want me to do your homework for you, $100 to my Paypal account will seal the deal! ;-)
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post #112 of 214 Old 12-02-2013, 12:27 PM
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Of course, but that is always true and does not inhibit measuring amplifier source impedance over a useful operational range,
Which is not the point of testing passive biamp, is it? You said you were going to test it, you had the load, you said you could disconnect the lf section...

So do the test you were speaking about.
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Impedance is generally thought to be a small signal parameter, and small signal parameters presume a linear system. Therefore the phrase "marginally distorting" is irrelevant to this discussion. Back to EGR 200...

Strawman argument again? Anything to avoid proving yourself incorrect. You present somebody else's graphs for output maximums through a range of load impedances and reactances, then lump the output into "small signal" and "linear". Nice try at diversion. But I knew that about you.
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Since you claim to be self-sufficient in this area, I'll give you the same offer as I gave Amir. If you want me to do your homework for you, $100 to my Paypal account will seal the deal! ;-)

So you're handwaving generalizations, presenting work of others with no real understanding of the ramifications, and now pretending that you'll offer to do our "homework".

You're a laugh a minute.

Your gyrations away from actual engineering follows a consistent pattern. I enjoy watching you dance about.

jn
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post #113 of 214 Old 12-03-2013, 06:47 AM
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To the OP:

The short answer to your question is yes, passive biamping can indeed produce a significant difference to your system. (edit: it is also possible that it may make NO difference whatsoever)

If you examine the graphs arnyk provided, the second one shows that it's available voltage will droop when the load impedance is lower, from a 28 or so volt level to about 10 volts. All speakers have impedance variations across the entire audio band, and for some of them, the impedance can get quite low, down into the 1 to 4 ohm range depending on the speaker itself.

If for example, you play music into that amp at the 28 volt level into an 8 ohm load, the amp will be capable of doing so. If the woofer has frequencies where it's impedance drops to 4 or 2 ohms, then whenever the music provides that frequency at a level in excess of that graph's ability , the woofer draw will be such that the amplifier will no longer be capable of producing the voltage and distortion of the entire signal will result. If you remove the woofer from that amplifier channel, the music will return to an undistorted state.

If the amplifier response were entirely linear, then passive bi-amping (edit, accidentally put biwiring here) would not change anything. But as you can see from the graphs, the full power output of an amplifier is not linear. There are limitations by design, such as the amount of power supply capacitors, the supply transformer robustness, as well as circuit details for the amplifier. All cost tradeoffs for typical manufacturers. Arnyk's copied/pasted graphs are not properly labelled to indicate what the lines represent, clipping or some distortion percentage, but do indeed indicate limitations on the output. They do not indicate if it is a current limit, a voltage limit, or some combination of both. My discussion of "foldback" is one where the output current limit is dependent on the output voltage, this being a scheme to limit power dissipation of the output drivers as they drive reactive load. A design utilizing foldback will indeed be more susceptible to the effect I discuss, and if your system engages foldback protection at the listening levels you demand, passive biamping may indeed make a difference. The test regimen I described to arnyk looks for that effect using an FFT on the output to find mid/high distortion.

In the best of worlds, an amplifer which "doubles down" below the speaker impedance minimum is preferred. (by double down, I mean that when you halve the load impedance, the power will double, there were no design restrictions holding the amplifier back.)

Most consumers do not have that luxury.

That said, I would recommend a crossover in front of the amplifiers so that you can pick up far more power from your equipment. Active biamping allows using beefy amps for the woofs, and much smaller ones for the mids and highs, giving you more bank for the buck.

jn

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post #114 of 214 Old 12-03-2013, 08:51 AM
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Originally Posted by jneutron View Post

and for some of them, the impedance can get quite low, down into the 1 to 4 ohm range depending on the speaker itself.
I'm in the market for speakers and sounds like I should be avoiding such speakers as a consumer. What models should I be avoiding? Thanks in advance.
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post #115 of 214 Old 12-03-2013, 09:08 AM
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I'm in the market for speakers and sounds like I should be avoiding such speakers as a consumer. What models should I be avoiding? Thanks in advance.

Don't make a choice of a speaker based on some number. Base it on what you like to hear, how they sound, and what you want to pay.

If a speaker is very hard to drive properly, then you also have to consider the amplifier cost as well. Lots of people here can let you know if a speaker you are looking at is a difficult one.


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post #116 of 214 Old 12-03-2013, 09:25 AM
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Quote:
To the OP:

The short answer to your question is yes, passive biamping can indeed produce a significant difference to your system. (edit: it is also possible that it may make NO difference whatsoever)
I think if you looked carefully at his actual system, and what he was proposing to do, you (or someone more reasonable than you, perhaps) would conclude that it is almost inconceivable that it would produce a significant difference in his system.

And if one really has a problem that passive biamping might ameliorate, it is still not the right approach to the problem. The right approach is to get a more powerful amp.

If you can't explain how it works, you can't say it doesn't.—The High-End Creed

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post #117 of 214 Old 12-03-2013, 09:44 AM
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I think the better reply would be that passive biamplification has as much chance of affect the sound of his system as a snowball has in surviving the night in the Amazon rain forest.
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post #118 of 214 Old 12-03-2013, 09:53 AM
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Originally Posted by mcnarus View Post

I think if you looked carefully at his actual system, and what he was proposing to do, you (or someone more reasonable than you, perhaps) would conclude that it is almost inconceivable that it would produce a significant difference in his system.

Couldn't pass up the insult I see. Some things remain the same.
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Originally Posted by mcnarus View Post

And if one really has a problem that passive biamping might ameliorate, it is still not the right approach to the problem. The right approach is to get a more powerful amp.
I see you neglected to point out that I preferred an option which was not passive biamping. Heaven forbid you have to admit I was correct.

jn

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post #119 of 214 Old 12-03-2013, 09:56 AM
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Originally Posted by FMW View Post

I think the better reply would be that passive biamplification has as much chance of affect the sound of his system as a snowball has in surviving the night in the Amazon rain forest.

As opposed to my statement that it could affect it, but then that it also may not.

I take it you've examined the schematics at the chip level to determine if foldback protection is being used to limit cross conduction dissipation caused by a reactive load? Or are you just here for colorful repartee?

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post #120 of 214 Old 12-03-2013, 10:49 AM
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Quote:
Originally Posted by jneutron View Post

To the OP:

The short answer to your question is yes, passive biamping can indeed produce a significant difference to your system. (edit: it is also possible that it may make NO difference whatsoever)

If you examine the graphs arnyk provided, the second one shows that it's available voltage will droop when the load impedance is lower, from a 28 or so volt level to about 10 volts. All speakers have impedance variations across the entire audio band, and for some of them, the impedance can get quite low, down into the 1 to 4 ohm range depending on the speaker itself.

If for example, you play music into that amp at the 28 volt level into an 8 ohm load, the amp will be capable of doing so. If the woofer has frequencies where it's impedance drops to 4 or 2 ohms, then whenever the music provides that frequency at a level in excess of that graph's ability , the woofer draw will be such that the amplifier will no longer be capable of producing the voltage and distortion of the entire signal will result. If you remove the woofer from that amplifier channel, the music will return to an undistorted state.

If the amplifier response were entirely linear, then passive bi-amping (edit, accidentally put biwiring here) would not change anything. But as you can see from the graphs, the full power output of an amplifier is not linear. There are limitations by design, such as the amount of power supply capacitors, the supply transformer robustness, as well as circuit details for the amplifier. All cost tradeoffs for typical manufacturers. Arnyk's copied/pasted graphs are not properly labelled to indicate what the lines represent, clipping or some distortion percentage, but do indeed indicate limitations on the output. They do not indicate if it is a current limit, a voltage limit, or some combination of both. My discussion of "foldback" is one where the output current limit is dependent on the output voltage, this being a scheme to limit power dissipation of the output drivers as they drive reactive load. A design utilizing foldback will indeed be more susceptible to the effect I discuss, and if your system engages foldback protection at the listening levels you demand, passive biamping may indeed make a difference. The test regimen I described to arnyk looks for that effect using an FFT on the output to find mid/high distortion.

In the best of worlds, an amplifer which "doubles down" below the speaker impedance minimum is preferred. (by double down, I mean that when you halve the load impedance, the power will double, there were no design restrictions holding the amplifier back.)

Most consumers do not have that luxury.

That said, I would recommend a crossover in front of the amplifiers so that you can pick up far more power from your equipment. Active biamping allows using beefy amps for the woofs, and much smaller ones for the mids and highs, giving you more bank for the buck.

jn

 

Most of the information in this post is wrong and my advice to the OP would be to ignore it.

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