Bi-amping with Yamaha rx767.

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jase250

90 posts

Master Geek

#70107 19-Oct-2010 00:38

Hi all.

I am using the ability of my receiver to reassign unused amps from surround rears to biamping the fronts. Having done this, I now feel that my midrange is slightly overpowering when listening to CDs, even after rerunning the setup mic. I haven't A/Bed it, so could well be imagining it, but on some songs the vocals seem disproproportionately loud. I suspect that this is due to an overlap of the frequencies being delivered to the high and low speakers. On the plus side, I have found a new joy in cymbals.

I was hoping someone could explain how the receiver determines what frequency band to send

to which internal amp. It's not really made clear in the manual as to which outputs are used for highs and lows, either - I have assumed that it is the ones labeled biamp that I connect to the top bindings on my speakers.

wmoore

510 posts

Ultimate Geek

#393430 19-Oct-2010 07:19

Hi

Just looked at the manual online, and on page 18 it shows the set up.
Starting with your left speaker, front right on your amp goes to HF on your speaker
Left front on the amp goes to LF on your speaker. On to the right speaker
Surround goes to HF and Bi-amp goes to LF on your speakers.
remember to remove links between HF and LF on your speakers.

"In the end, it's not the years in your life that count. It's the life in your years." -
-- Abraham lincoln

Jaxson

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#393491 19-Oct-2010 09:38

Just a quick check, but doesn't the amplifier send the same signal out when bi amping, leaving the speakers internal crossover circuitry to decide what signal it actually plays via each speaker? I didn't think the receiver 'split' the signal itself as such?

bazzer

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#393529 19-Oct-2010 11:05

Jaxson: Just a quick check, but doesn't the amplifier send the same signal out when bi amping, leaving the speakers internal crossover circuitry to decide what signal it actually plays via each speaker? I didn't think the receiver 'split' the signal itself as such?

richms

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#393689 19-Oct-2010 17:04

Correct, this is commonly known as fools biamping since it really doesnt achieve anything over using a single amp unless you are running things into distortion.

Richard rich.ms

jase250

90 posts

Master Geek

#393827 20-Oct-2010 00:03

Ah, well that's disappointing to hear. I had assumed the receiver was smarter than that and figured out what to send where when it ran the setup. It kind of made sense that it would measure the frequesncy response of the hf and lf speakers independently and then apply a high/low pass filter accordingly.

Having read a bit more about the cicuitry inside a speaker I can see how this was a bit much to expect - it seems that if the receiver could do this, I would be required to open up the speaker and disconnect the crossover.

If the same signal is being sent from both outputs on the receiver, then it doesn't matter which bindings I connect them to on the speakers, I guess.

Oh well, live and learn.

Heh - "fool's bi-amping" indeed. I can't see how it would be beneficial at all if it is just the same signal being sent, but I don't claim to be an expert (obviously). Amazing what the placebo affect can do to your ears - but I swear that my highs are more defined... should I expect this?

richms

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#393832 20-Oct-2010 00:56

Well it will allow you to change the levels somewhat, and it will mean that if you are pushing the amp to distortion that the HF will be unaffected by it, but that would mean running the system stupidly into distortion.

The passive crossovers normally have a great resistor in them to make the levels right, since the tweeter is more efficient than the woofer. To get any gains you would have to remove that attenuation, the rest of the crossover design (assuming its not just a craphouse speaker with a single capacitor) is to correct for the baffle and other things causing a deviation from a flat response, so not messing with that is important unless you have some way to do that in a DSP.

If you are going to do it, you just need to place your line level crossover points well below the 3dB point of the one in the speaker so that they are not going to have any additional effect on it, will mean that you are not expecting the amp driving the tweeters to do the voltage swing that the heavy bass causes, so it may mean you can get a little bit more power out of the system since the amps will be doing less, but again minimal

IMO, the idea that the audio world has that a speaker has to be ruler flat and that you shouldnt do any EQ is absurd, but the industry is full of people with their little wooden cones for things and gold plated IEC cables so logic is clearly the loser in any discussion with audiophools.

if you want to play with a software crossover there is one for foobar2000, which you can use HDMI out and use the different surround and rears to do the mids and highs and change crossover points in software, but a friend did it and the result was just more controls to mess with and make it sound bad. I have done it on a 5.1 analog card to drive 60Hz into some small floorstanders that image nice, but I am running out of power on the bass before the others are anywhere near their limits so I have to get more power.

Richard rich.ms

elldizzle

91 posts

Master Geek

#393965 20-Oct-2010 13:17

So what your saying is that apart from putting slightly less load on your amplifier. There seems to be no gain Bi-amping over Bi-wiring. Because the same signal is being sent by the reveive, Regardless of the fact the HF or LF is being driven by an independant channel?..

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richms

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#393992 20-Oct-2010 14:11

May be less heating of the amp chips slightly, might get a few more watts in total out of it before distortion, but that will not be constant across all material.

If the amps had independent power supplies and that was the limiting factor then there would most likely be a demonstrable decent improvement in the amount of power available, with it just being the voltage drop of the output devices you are making a change to, and most of them being very good these days, maybe a dB or 2 more - hardly worth it unless you are really pushed for that little bit extra and do not want to go out and buy a real power amp.

Richard rich.ms

Jaxson

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#393996 20-Oct-2010 14:19

This reminds me of reading that some speaker manufacturers were basicaly forced into configuring their products to allow bi wire/amping even though they didn't perceive a need, simply becuase customers were expecting it and it counted against them in a features comparison. ie the other brands all got to slap 'bi ampable' on their spec sheets.

elldizzle

91 posts

Master Geek

#394003 20-Oct-2010 14:50

Well all I know is I have my wharfedales hooked up the rugular way with the jumpers between the High and Low inputs and they sound awesome to me!!

Dunnersfella

4086 posts

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#394122 20-Oct-2010 20:11

Jaxson: This reminds me of reading that some speaker manufacturers were basicaly forced into configuring their products to allow bi wire/amping even though they didn't perceive a need, simply becuase customers were expecting it and it counted against them in a features comparison. ie the other brands all got to slap 'bi ampable' on their spec sheets.

If customers ask for bi-wire capable speakers, then no one is really being 'basically forced' into anything...
They're just changing to meet customer demand.
For instance, red cars may become a trend... so companies that have previously only made vehicles that are British Racing Green, then need to bring out something red in order to maintain / grow market share...
It certainly won't make their cars perform better in the manufacturers eyes, but in the customers hearts, they'll be fantastic. And ultimately, that's all that counts.

Jaxson

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#394304 21-Oct-2010 11:01

Ok, from what I was reading, the speaker manufacturer would not have normally provided this feature as they did not find it enhanced the design of their speaker product. However, given the hype around the practise they felt obligued to offer that for those who wanted to hook their system up that way.

The point was they manufacture themselves didn't really buy in to the concept.

Each to their own though.

Dunnersfella

4086 posts

Uber Geek

#394536 21-Oct-2010 21:11

I do know of one speaker manufacturer who said his speakers feature bi-wiring posts in order to encourage customers to run quality amps... thus reducing the chances of people using cheap, under powered amps and doing damage (both physically and reputation wise) to the speakers.