Should I bi-amp with Yamaha RX-A3000?

[PENG]

Thanks for the info. It is much appreciated. Was that link you speak of in this thread or another? I couldn't find it in this thread. Could you post it again?

Thanks.

It is in another thread, see post#12 for the link.

http://forums.audioholics.com/forums/showthread.php?t=72952&page=2

 

[jeannot]

Hi all,

I am running a 5.1 setup and was wondering if it was worth the little bit of extra wire to bi-amp with my new RX-A3000.

With the amps set to 5.1 mode, are the other two channels and their wattage going unused? Or does the receiver allocate more power to the other speakers?

I believe my front speakers will end up being Boston Acoustics VS 336...if that matters.

Thanks for any input.

Bi-amping's advantage relates to:
1-Power. Your higher frequency amp is freed from having to deal with difficult woofers, so it works at less power and can deliver better sound. And if you drive your system close to clipping, only your low amp is likely to clip, not affecting the sound of your high amp. So you can destroy your amp and speakers while enjoying less distortion.

2-Sound quality. Only IF an active cross-over is used.
2a-Most AVRs are not equipped to let you insert an active cross-over between the preamp and the amps, so you would need external amps. Unless you're lucky enough to have a receiver that implements an active cross-over in bi-amp mode.
2b-An active cross-over only provides benefit if you REMOVE:
2b1- The high-pass part of the passive cross-over the high part of the speaker. That is normally a capacitor/inductor circuit that introduces phase shifts.
2b2-The low-pass part of the passive cross-over of the lower part of the speaker. That is because a lot of woofer damping is wasted in the cross-over inductors, and bi-amping allows removing these inductors for a cleaner and tighter bass.
Few people understand this and even less actually do it.

 

[PENG]

Only IF an active cross-over is used.

Again, this is hearsay, an opinion at best, not necessarily factual.

 

[jeannot]

Again, this is hearsay, an opinion at best, not necessarily factual.

It is widely known, and proven that one of the biggest advantages (not the only one!) of an active cross-over is that it replaces a passive cross-over.

Passive cross-overs impose a non-resistive load to the amplifier, and amplifiers do not like non-resistive loads. They also add resistance in series with the drivers, which adds to the amplifier output resistance and affect the damping factor. Inductors are made of over 50 feet of 16-18 gauge wires. Moreover, the low-pass cross-overs implemented with an inductor with a metal core have been measured to act like dynamic compressors because of the hysteresis of their core.

This hearsay is also shared by my teachers in my Electronic Engineering courses.

 

[PENG]

It is widely known, and proven that one of the biggest advantages (not the only one!) of an active cross-over is that it replaces a passive cross-over.

Passive cross-overs impose a non-resistive load to the amplifier, and amplifiers do not like non-resistive loads. They also add resistance in series with the drivers, which adds to the amplifier output resistance and affect the damping factor. Moreover, the low-pass cross-overs implemented with an inductor with a metal core have been measured to act like dynamic compressors because of the hysteresis of their core.

This hearsay is also shared by my teachers in my Electronic Engineering courses.

No there is no prove, just opinions. It is like you cannot prove a tube amp is better than a solid state amp. There are too many variables. In terms of theory, of course it is clear there are differences in terms their implementation and from electrical theory stand point, between using external active crossovers and internal OEM crossovers. I am simply pointing out the fact that there are at least two schools of thoughts, or opinions if you prefer to call it that, in terms of which one provide better sound quality. My own opinion is like most other forum members (based on what I have read so far), that any such sound quality improvements are not discernible by the average person. It does not mean it is not there, just that I can't tell it is there or not. So to me it is a moot point, but I don't want people to read what you wrote (seemed like it was stated as facts), and then spread it around as facts when it is just an opinion/hearsay. I am sure you know the definitions of hearsay. Did you actually read the proof with equations, forumla etc., that typically would involve Laplace transforms, Fourier analysis that are quite essential in filter designs and circuit analysis/synthesis.

With all due respect I don't know how much your teacher knows about electronic engineering and whether you took what he/she said out of context. I am not going to go deep into the academic side as it is not easy to explain the details in forums like this or people don't have to spend minimum 4 years in engineering schools. Suffice for me to provide at least one link to people who know better than the average forum member. You can follow that link and read about why Anthem referred to something like what you were telling people as ".....myth....." and let's call it the day. Regardless, I am done on this controversial topic, respectfully....

 

[mrceolla]

No fighting.

What Anthem says makes sense to me. The internal cross overs of a good quality speaker must be better tuned to that speaker's drivers than a generic external cross over.

However, the question still remains... Will I get any audible bennefit from bi-amping with a single AV receiver?

It seems like most people think not. If there is no bennefit, why are so many receiver and speaker manufacturers offering this functionality. Is it just another one of those bells and whistles that don't really do anything useful?

Not that it matters, but here's what the Boston Acoustics VS 336 manual has to say:

"The dual input terminals of the VS 325C, VS 344, and VS 336 also allow for
bi-amplifying. Two separate amplifier channels are used to drive the speaker.
One channel drives the bass speakers while the other drives the midrange/tweeter. This can provide significant improvements in audio quality and dynamic range.

In this configuration the metal straps that connect the two set of terminals are removed. The amplifier channel driving the midrange/tweeter is connected to the top terminals; the amplifier channel for the bass speakers is connected to the bottom terminals."

Here's what the Yamaha RX-A3000 has to say:

"Using the front speakers that support bi-amp connections reproduces a high quality sound"

"This unit can be connected to speakers that support bi-amp connections. When connecting speakers, connect the FRONT jacks and the SURROUND BACK/BI-AMP jacks as in the diagram below. Configure the bi-amp settings to activate connections."

So, would you all still skip the bi-amping if you were me?

Is there anyone out there with a single AVR that does bi-amp?

Thanks again for all of your input.

Mike

 

[Swerd]

This question of bi-amping by utilizing unused channels of an AVR has come up several times before.

This thread has a few things to add to the discussion.

http://forums.audioholics.com/forums/showthread.php?p=651478&mode=linear&highlight=bi-amp#post651478

The bottom line is that there is little if anything to gain by doing this, and AVR and speaker manufacturers do customers a disservice by placing this misinformation in their manuals. I suspect the marketing people have overruled the engineers.

jeanot - I'm glad you paid attention at engineering school, but you grossly overestate the advantages of active crossovers. They really only provide an advantage for crossovers below roughly 400 Hz.

The very large inductors required at those frequencies are expensive, react differently at elevated temperatures (which will occur inside a working speaker cabinet) and do create insertion losses due to resistance.

At higher frequencies, however, the advantages of active crossovers are largely theoretical, and there can be just as many disadvantages. For one, active crossovers are expensive. The opportunity for an owner to "design" his own crossover may work well, but can also create a crossover that actually performs worse than what the speaker maker originally built. This isn't for inexperienced amateurs.

 

[jeannot]

... My own opinion is like most other forum members (based on what I have read so far), that any such sound quality improvements are not discernible by the average person.

This is a recurring theme. A discussion on what is better is again, savagely attacked by the argument: yeah, but it's is not noticeable.

My assumption is that the people in these forums want better than the "average person" has, or at least want understand what is involved.

I'm sorry this turned into a pissing contest. It really did not have to.

 

[PENG]

This is a recurring theme. A discussion on what is better is again, savagely attacked by the argument: yeah, but it's is not noticeable.

My assumption is that the people in these forums want better than the "average person" has, or at least want understand what is involved.

I'm sorry this turned into a pissing contest. It really did not have to.

I never intended to say anything that could make you feel "....attacked....". If I knew it could, I would have not said any such things. Again, I am done with this topic but before I move on I would like to apologize for making you feel attacked and assure you that I did not mean to.

 

[mrceolla]

Ok, so I've spent all night reading posts and articles on this subject. I understand the argument that bi-amping with a single AVR may not increase the power to the bi-amped speakers much if at all.

But what about the fact that a single applifier channel now only has to deal with either high/mid or low frequencies. It would seem that this could provide a bennefit in terms of lower frequencies not effecting higher frequencies (and vise versa) running over the same cable. Or does this only happen if one or the other is clipping?

Is it safe to assume that with an AVR that allows for this, and set to that mode, that it separates the frequencies sent out of each of the bi-amp channels? In my receiver's case, the front channels would supply the low end and the surround back would provide the mid/high end. And is this not a good thing?

It appears these speakers have two separate circuit boards inside. I can only assume one is for the 3 woofers and the other for the mid/high. Will the speaker's internal electronics not perform better if they have a narrower frequency range to deal with?

Please explain why this would provide little to no bennefit.

And if anyone is interested, here's the URL to audioholics review of my receiver. This particular page tests the amp section.

http://www.audioholics.com/reviews/receivers/rx-a3000/rx-a3000-measurements-cont

Thanks for your continued input. I need to KNOW and mostly understand why it's worthless before I can get it out of my head.

 

[davidtwotrees]

I was obsessed with biamping. What I did was take an Acurus A-250 and wired one channel to the lf binding posts, and then wired the other channel to the hf binding posts. Then I took a second Acurus A-250 and did the same thing to the other speaker. The speakers were Canton Karat L800DCs, with 250 wpc into each section of some pretty darn good speakers. I wanted to hear a difference. But at the end of the day there was none. Nada. Zip. It sure looked cool with an amp sitting by each speaker. And I could say the word Biamp. Biamp. It sounds cool. But at the end of the day, when I put my objective hat on and was logical and common sensical. All I had was some cool factor. And I stopped obsessing over the Biamp conundrum and moved on.
So. If you want to Biamp with a home theatre receiver, after what I've just said and all the other folks here have just said, go for it. But be objective. Use logic. If you hear something then, good for you.

 

[lsiberian]

Bi-amping's advantage relates to:
1-Power. Your higher frequency amp is freed from having to deal with difficult woofers, so it works at less power and can deliver better sound. And if you drive your system close to clipping, only your low amp is likely to clip, not affecting the sound of your high amp. So you can destroy your amp and speakers while enjoying less distortion.

2-Sound quality. Only IF an active cross-over is used.
2a-Most AVRs are not equipped to let you insert an active cross-over between the preamp and the amps, so you would need external amps. Unless you're lucky enough to have a receiver that implements an active cross-over in bi-amp mode.
2b-An active cross-over only provides benefit if you REMOVE:
2b1- The high-pass part of the passive cross-over the high part of the speaker. That is normally a capacitor/inductor circuit that introduces phase shifts.
2b2-The low-pass part of the passive cross-over of the lower part of the speaker. That is because a lot of woofer damping is wasted in the cross-over inductors, and bi-amping allows removing these inductors for a cleaner and tighter bass.
Few people understand this and even less actually do it.

This is well stated, but not entirely true. Biamping has the potential to provide SQ benefits even to a passively crossed system. For example lets say you have a hot tweeter. You could actually reduce the tweeter level by employing passive components in a bi-amped setup. Biamping also can raise the clipping level for each component. With some creativity biamping is a powerful tool in an engineers arsenal.

Active crossovers IMO are much easier to use and implement, but they are not without drawbacks such as the need for a power supply.

I realize that it requires some tapping into the power of passive biamping requires some unconventional thinking, but I don't think the approach is completely useless.

Again, this is hearsay, an opinion at best, not necessarily factual.

I think it's a mixture of fact and opinion. I certainly don't see any harm in trying it out. Wire is dirt cheap and life is boring. Why not give it a go?

 

[mrceolla]

FYI, here's what Yamaha customer support had to say:

"With our Bi-Amp feature you are using discrete amps, the front and the surround back. So there is a difference in volume and sound quality. I myself use it on my speakers and can hear the difference."

Thoughts?

 

[Swerd]

FYI, here's what Yamaha customer support had to say:

"With our Bi-Amp feature you are using discrete amps, the front and the surround back. So there is a difference in volume and sound quality. I myself use it on my speakers and can hear the difference."

Thoughts?

The limiting factor to amplification is the capability of the power supply transformer. In a sense, this acts like a car's engine, and the power ouput transistors act more like a car's transmission. If you want more power, you need a bigger power supply transformer.

In your case, you have the same power supply and are dividing its capability into more output channels. You haven't added any ability to deliver power. Only by adding external amplifiers, with their additional power supply transformers, can you deliver more power to your speakers.

If your receiver has enough power to begin with, and I think yours does, the whole argument about bi-amping becomes silly. There is very little (if any) benefit and it costs a lot of money. It is also very difficult to determine with blind testing whether there is any (even if slight) audible benefit to bi-amping. Without blind testing any claims of audible benefit are only hearsay unsupported by any evidence.

It's a real disservice that home theater receiver makers say this in their manuals. It is wrong and causes a lot of confusion. It think it stems from the fact that people pay a lot of money for their receivers and they don't like the idea of not using 2 channels if they have a 5 channel speaker system, as many people do.

 

[3db]

The limiting factor to amplification is the capability of the power supply transformer. In a sense, this acts like a car's engine, and the power ouput transistors act more like a car's transmission. If you want more power, you need a bigger power supply transformer.

In your case, you have the same power supply and are dividing its capability into more output channels. You haven't added any ability to deliver power. Only by adding external amplifiers, with their additional power supply transformers, can you deliver more power to your speakers..

Thats two of us that said now. I wonder..

If your receiver has enough power to begin with, and I think yours does, the whole argument about bi-amping becomes silly. There is very little (if any) benefit and it costs a lot of money. It is also very difficult to determine with blind testing whether there is any (even if slight) audible benefit to bi-amping. Without blind testing any claims of audible benefit are only hearsay unsupported by any evidence.

It's a real disservice that home theater receiver makers say this in their manuals. It is wrong and causes a lot of confusion. It think it stems from the fact that people pay a lot of money for their receivers and they don't like the idea of not using 2 channels if they have a 5 channel speaker system, as many people do.

It doesn't bother me not to use 2 channels..At least I odn't lose any sleep over it. I'm thinking of using the 2nd zone to power some out door speakers around my hot tub.

 

[jeannot]

I struggle with the fact that the manufacturer appears to claim it is worthwhile.

Sometimes manufacturers claim something for marketing reasons, when they have a feature that the competition may not have.

And the speakers I will be using offer that capability. Yet many seem to say it is pointless.

Many do, many don't. Everything you hear are either opinions or personal experience, but nothing beats you grabbing a few feet of wire and a cutter, and making the rubber hit the road.

So let me get this straight. In order for it to be worthwhile, I need 2 physically separate amps (unused channels in one AVR don't count) and then I need to disconnect the speaker's internal crossovers? Is there anything else I'm missing?

2 Physical separate amps, it depends. Sometimes, the limitation is more the amp itself, due to the limits of its output stage. In that case, 2 amps on the same power supply may perform better than 1 even though they share the same power supply. If you decide to disconnect your cross-over, you have to be careful. Removing the low-freq x-over is simple, but the high freq cross-over may be more complex in a 3 or 4-way.

I know I could simply try it. But as I sit here waiting for the speakers to arrive, I'd rather determine if it's worth it then either do it or don't and leave it be. I've also got cable molds/tracks that I'd need to run wire through and the back of the reciever isn't easily accessible. So I'd like to do it once and do it right. Know what I mean?

Yep. Unless like me, there's a chance you may wake up in the middle of the night thinking may be, just may be you should have tried.
However I will take a chance, and claim that the majority of people here would agree that bi-amping cannot sound worse. So, if your setup makes switching painful and you would like to take only one shot at this, may your best bet is to just bi-amp.

 

[jeannot]

The limiting factor to amplification is the capability of the power supply transformer.

This is not black and white, it may be the case with sine waves on resistive loads like on a bench, but on reactive loads, sometimes the output transistors may be the limiting factor because of the current/damping demands of a woofer, in that case you add current capability by using two amps. Again, depends, on the amp, depends on the speaker, and the operator.

Without blind testing any claims of audible benefit are only hearsay unsupported by any evidence.

Can audible differences be proven? That is the question.

It's a real disservice that home theater receiver makers say this in their manuals.

Agreed. However, if a claim makes the manufacturer sell more receivers, wasn't the claim worthwhile to the manufacturer?

 

[jinjuku]

Bi-amping with a receiver is like switcing deck chairs on the Titanic...

 

[3db]

Bi-amping with a receiver is like switcing deck chairs on the Titanic...

clever phrasing but it really doesn't help the OP seek clarification.

 

[mrceolla]

Hi all,

Thanks again for all the input. I asked Yamaha customer service:

"When in bi-amping mode, is the exact same signal sent out of the front and surround back channels? Or is an active cross over used sending only lows out the front channels and mid/high out of surround back?"

Their response:

"It sends out the full signal on both and the speaker cross over would take care of it."

So I guess that answers my question about bass clipping effecting mid/high.

So I've come to this conclusion thus far. Bi-amping with a single AVR provides no high/low signal separation and questionable power increase when not maxing out your output and no power increase when maxing out your output. Does that sound right?

But what about this... Does bi-amping with a single AVR provide greater control of high/low frequencies by allowing you to boost or lower the discrete amplifiers separately? IOW, if I want more mid/high, can I boost the levels coming from my surround back channels feeding the midranges and tweeters while leaving the front channels feeding the woofers alone? Is this possibly better than using the builtin equalizer?

I'm not even sure my AVR will allow for this, but if it can, could that make bi-amping worthwhile?

Thanks.