![](/boards/images/icons/default/book.gif) Re: bi-amping with m80s
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Joined: May 2003
Posts: 18,044
shareholder in the making
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shareholder in the making
Joined: May 2003
Posts: 18,044 |
Headroom means the spare power (JohnK, ClubNeon, and FredK will kill me over my explanation here) that is available over average power usage/volume level/program material. In other words, how much power is available for peaks in the material.
I am the Doctor, and THIS... is my SPOON!
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![](/boards/images/icons/default/book.gif) Re: bi-amping with m80s
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Joined: Dec 2007
Posts: 7,786
axiomite
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axiomite
Joined: Dec 2007
Posts: 7,786 |
Actually, I think thats a great explanation. Most would agree that headroom is a good thing. Some just think you need a lot more than you usually do.
Fred
------- Blujays1: Spending Fred's money one bottle at a time, no two... Oh crap!
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![](/boards/images/icons/default/book.gif) Re: bi-amping with m80s
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Joined: May 2002
Posts: 10,654
shareholder in the making
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shareholder in the making
Joined: May 2002
Posts: 10,654 |
Sure, Ken; that's fine. Unless the source material is one of those uniformly loud pop CDs with practically zero dynamic range(such as the one described in the study in my AES Journal that I've mentioned before), there has to be more power capacity than the 1 watt or so which is used at a comfortably loud average level. But if say 20dB(100 times the power)of headroom is enough for even the most dynamic classical or other material, buying still more is meaningless. Unused headroom is simply that: unused.
Uh oh; typing lag has reared its ugly head again.
-----------------------------------
Enjoy the music, not the equipment.
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![](/boards/images/icons/default/book.gif) Re: bi-amping with m80s
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Joined: May 2010
Posts: 310
devotee
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devotee
Joined: May 2010
Posts: 310 |
No. Your manual will clearly state not to bi-amp 4Omh speakers. agreed, that's why i said make sure it was rated (in everyway you need/want to use it at 4 ohms) and that it wasn't going to harm the receiver or anything. that's also why i like to say folks need to do research on their gear, i.e. reading the manual. so i'm with you on your response!
SonySXRD55" Marantz AV7702MKII pre-amp Emotiva XPA-5,UPA-2amps, 14 Speakers, All Axiom Oppo 105D&93
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![](/boards/images/icons/default/book.gif) Re: bi-amping with m80s
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Joined: Nov 2008
Posts: 1,789
connoisseur
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connoisseur
Joined: Nov 2008
Posts: 1,789 |
...JohnK, ClubNeon, and FredK will kill me over my explanation here... We all gotta die of something Ken. Might as well be by an angry JohnK/Clubneon/FredK mob rushing your HT room with torches screaming, "BURN THE HEADROOM BELIEVER, BURN HIM"!!!!!! Then stringing you up by HDMI 1.4 cable to make an example out of you for the world to see. At least that would be an original death.
My Stuff :
M80's QS8's VP150 EP800 Denon 4802 Emotiva XPA-3 Samsung BD-P3600 Sharp 65 Inch Aquos LCD
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![](/boards/images/icons/default/book.gif) Re: bi-amping with m80s
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Joined: Jul 2004
Posts: 4,444 Likes: 16
connoisseur
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connoisseur
Joined: Jul 2004
Posts: 4,444 Likes: 16 |
A receiver has only one amplifier with several channels of output transistors to distribute that power. John (or anyone who knows), Can you elaborate on this some? I've always had trouble wrapping my head around how this actually works. If an amplifier's roll is to increase the amplitude of signal that represents sound in a channel, how do these transistors play into this when there are several discrete channels with their own independent signals? And how does the newer Denon receivers with assignable amplifiers fit into this?
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![](/boards/images/icons/default/book.gif) Re: bi-amping with m80s
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Joined: Feb 2009
Posts: 3,466
connoisseur
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connoisseur
Joined: Feb 2009
Posts: 3,466 |
The transistors are valves which let the central pool of current flow from the power supply to the speaker behind them. So one pool of power, but multiple outlets. If you open all the valves at the same time the single power supply may not be able to feed them all.
The newer receivers with assignable channels, just have multiple speaker connectors behind one output device. A relay selects which connector gets the power.
Pioneer PDP-5020FD, Marantz SR6011 Axiom M5HP, VP160HP, QS8 Sony PS4, surround backs -Chris
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![](/boards/images/icons/default/book.gif) Re: bi-amping with m80s
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Joined: Jul 2004
Posts: 4,444 Likes: 16
connoisseur
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connoisseur
Joined: Jul 2004
Posts: 4,444 Likes: 16 |
So the transistors work like flow control valves then? Where do they get their command signal from? What does the amplifier do? I always thought the amplifier was the control point for power to the speaker, by your description, I obviously wrong.
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![](/boards/images/icons/default/book.gif) Re: bi-amping with m80s
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Joined: Feb 2004
Posts: 1,863
connoisseur
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connoisseur
Joined: Feb 2004
Posts: 1,863 |
The transistors are valves which let the central pool of current flow from the power supply to the speaker behind them. . depending on the configuration, transistors also amplify the signal as well as controlling the flow...
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![](/boards/images/icons/default/book.gif) Re: bi-amping with m80s
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Joined: May 2002
Posts: 10,654
shareholder in the making
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shareholder in the making
Joined: May 2002
Posts: 10,654 |
Yeah, Mike; the output transistors can be viewed as valves. They have no power of their own, but their function is to apportion the required amount of voltage from the central power supply section out to the speaker. Amplifiers have a fixed gain, generally around 28-30dB, which means that the incoming voltage is amplified about 25-30 times. Let's say that a particular one has a gain of 29.03dB, an increase of 28.3 times. If at a particular instant in time 0.1V is input on a channel, the output transistors have to add enough voltage from the power supply section for the designed amplification factor, and the output to the speaker is 2.83V. If the impedance of the speaker is 8ohms, this results in 1 watt being used(Ohm's Law, power equals voltage[squared]/impedance). As the voltage input varies constantly during music, so does the amount of voltage that the output transistors have to draw from the power supply section.
Those receivers with assignable channels(not assignable amplifiers)can just change what source of voltage is sent to the assigned set of output transistors. For example, the usual back surround channel can instead be sent the front channel voltage signals. The designed amplification then takes place as usual.
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Enjoy the music, not the equipment.
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