The Difference Between Bi-amping and Bi-wiring

[RichB]

Haven't heard back from Yamaha yet, but how about this statement from the Features section of that manual:
What story are they telling here?

Likely, a misleading one. If it were all channels driven, they would say so.
However, ACD has little bearing on its suitability for your needs since that that is not a realistic load.

This says it all:

It is similar to a 4-wheel drive car with one engine. It doesn't matter if you choose 2-wheel drive or 4-wheel drive, the engine can deliver only so much power. Your receiver's amp section can only deliver the power that its power supply transformer is capable of producing. It is up to you how many channels you use.

- Rich

 

[Swerd]

Haven't heard back from Yamaha yet, but how about this statement from the Features section of that manual:

Built-in 7-channel power amplifier
Minimum RMS output power (20 Hz to 20 kHz, 0.06% THD, 8 Ω)
Front: 105 W + 105 W
Center: 105 W
Surround: 105 W + 105 W
Surround back: 105 W + 105 W​

What story are they telling here?

This is what it says to me:

This 7-channel power amplifier was measured for minimum RMS output power (20 Hz to 20 kHz, 0.06% THD, 8 Ω)
When the two front channels were driven, power was 105 W in each channel.
When the center channel was driven, power was 105 W.
When the two surround channels were driven, power was 105 W in each channel.
When the two surround back channels were driven, power was 105 W in each channel.​

What Yamaha doesn't say is as important as what they do say. Their choice of words is misleading. Is that because of unfortunately poor wording, or was it a deliberate choice? Either way, it's misleading. They should write their performance specs, so you don't have to have a lawyer to understand their meaning.

I believe Yamaha is complying with the FTC regulations, but their wording allows people, who are willing to believe what they imply but don't directly say, to fool themselves. Don't be one of them.

 

[mardukes]

According to Raj of the Yamaha Support Team, "Yes you are getting 200 watts to your front LEFT/RIGHT speakers when you are using BI-amp." Are you thinking the parsing here is that he doesn't say to each of your front LEFT/RIGHT speakers? Is it possible this is a 700 watt power amp?

How about I bi-amp the top with my languishing NAD-3150! It allows me to jump behind the pre-amp.

 

[Swerd]

According to Raj of the Yamaha Support Team, "Yes you are getting 200 watts to your front LEFT/RIGHT speakers when you are using BI-amp." Are you thinking the parsing here is that he doesn't say to each of your front LEFT/RIGHT speakers? Is it possible this is a 700 watt power amp?

Yes, I would be very skeptical about what they claim.

When Yamaha stated its receiver's power, it was 105 wpc when two channels were driven. They are required to measure it like that by the FTC. I assume they weren't fudging those results because the FTC, if it were inclined, could audit those results, and if false, fine them for false advertising.

The Yamaha Support Team claimed that you could get 200 watts to your front left and right speakers when you bi-amp them. To do so requires that you use four channels on your receiver. Yamaha did not measure the power available under those conditions. You should not assume it will be the same as when two channels are used. It might actually be 100 wpc when all channels are driven, but until those measurements are actually done and shown in writing, you know nothing for sure.

 

[mardukes]

Interesting. Listing on Amazon.com:

Yamaha RX-V863BL 735 Watt 7.1-Channel Home Theater Receiver (Discontinued by Manufacturer)

on line spec sheet @yamaha.com:
RMS Power (8 ohms, 20Hz-20kHz) [THD] 105W x 7 [0.06%]

 

[Swerd]

Interesting. Listing on Amazon.com:

on line spec sheet @yamaha.com:
RMS Power (8 ohms, 20Hz-20kHz) [THD] 105W x 7 [0.06%]

It doesn't matter what Amazon says. They don't have to answer to the FTC, but Yamaha does.

The FTC in 2008 considered revising its rules on: Trade Regulation Rule Relating to Power Output Claims for Amplifiers Utilized in Home Entertainment Products

Federal Register/ Vol. 73, No. 39 / Wednesday, February 27, 2008 / Proposed Rules
http://www.ftc.gov/sites/default/files/documents/federal_register_notices/trade-regulation-rule-relating-power-output-claims-amplifiers-utilized-home-entertainment-products/080227trade.pdf​

In 1974 the FTC, "issued the Amplifier Rule to assist consumers purchasing power amplification equipment for home entertainment purposes by standardizing the measurement and disclosure of various amplifier performance characteristics (39 FR 15387). The Rule establishes uniform test standards and disclosures to aid consumers in making meaningful comparisons of amplifier performance attributes." It's existing rule used "continuous measurement to represent the maximum per-channel power an amplifier can deliver over a five minute period."

The FTC considered revising this rule to reflect multi-channel home theater receivers, as opposed to two channel stereo receivers. The three proposed alternatives were:

1. all channels associated as one group;
2. the front right and left channels and the center channel associated as one group, and the surround channels associated as a second group;
3. the front stereo channels associated as one group, the center channel treated as a second group, and the surround channels associated as a third group.

The FTC ultimately decided to adopt option 3, as it most resembles their original 1974 rule. Because the home theater market had several competing receiver makers, the FTC decided that consumers had plenty of options, and that no further regulation was needed.

Yamaha does say on page 2 of their online manual
http://download.yamaha.com/api/asset/file/?language=en&site=usa.yamaha.com&asset_id=35547

Built-in 7-channel power amplifier
◆ Minimum RMS output power (20 Hz to 20 kHz, 0.06% THD, 8Ω)
Front: 105 W + 105 W
Center: 105 W
Surround: 105 W + 105 W
Surround back: 105 W + 105 W​

This is precisely what the FTC requires.

You have claimed that your receiver does produce 105 wpc when all 7 channels are driven. Yamaha (and their lawyers) clearly know what the FTC rule says, and your version is not correct.

It's your receiver and your speakers. You can do whatever you like with them. And I'm OK with that. But if you persist in claiming what is false on this audio forum, I'll call you on it every time.

 

[mardukes]

I'm asking to be called such things. However, I'm going to have to call you on missing the distinction between Amazon.com and Yamaha.com:

on line spec sheet @yamaha.com:
RMS Power (8 ohms, 20Hz-20kHz) [THD] 105W x 7 [0.06%]

It's on the internet so it's got to be true, right?

How about this I found @ SoundandVision.com. I'm going to have to call Raj on this!

HT Labs Measures: Yamaha RX-V863 A/V Receiver

Five channels driven continuously into 8-ohm loads:
0.1% distortion at 42.6 watts
1% distortion at 48.4 watts

All channels driven continuously into 8-ohm loads:
0.1% distortion at 41.6 watts
1% distortion at 47.9 watts

 

[PENG]

I'm asking to be called such things. However, I'm going to have to call you on missing the distinction between Amazon.com and Yamaha.com:


It's on the internet so it's got to be true, right?

How about this I found @ SoundandVision.com. I'm going to have to call Raj on this!

S&V reported as they found, but in many cases those low numbers were resulted from the protective circuit activating and the point such systems activate varies between manufacturers, models and year of manufacture. For example, the older and much lighter, with smaller power supply Denon 4310 tested with much better ACD numbers than the much heavier and newer Denon 4810 that also cost almost twice as much.

 

[RHSmith]

I also have a Yamaha RX-V863 and am also a retired sr. repair audio tech and having repaired 10's of thousands of amps/receivers over the years of all types and power levels up to several 1000wpc.. I put my RX-V863 on my repair bench and can tell you that the Yamaha meets it's PUBLISHED specs as per the FTC requirements... but you have to understand how that is arrived... and when all channels are driven it is NOT 105 wpc... it does drop to about 40-42 wpc... hence in my system the use of a pair of Accuphase P-300 amplifiers (165wpc@8, 325wpc@4) for the L/R + Center configuration as well as 2 Hafler D500 amps (265wpc@8, 525wpc@4) for the 4 NHT 1259 DIY subs in my system. This way the Yamaha internal amps drive just the surrounds with ample power..

 

[RHSmith]

I have bi-amped/tri-amped for years.. since the mid 70's.. It is truly the only way to go on modest to high power systems. I use active crossovers and large power. The improvements on transient control, dynamics and the lower IMD are well worth the cost. And speaker reliability goes up too.. Removing the problem of clipping of the high-end amp with excessive bass levels from the equation notably improves midrange and tweeter reliability at high power levels as well as keeping the top-end from sounding harsh and nasty when the bass gets driven too hard. Having a good power amp (something with a REAL 2:1 current/power/impedance ratio -> 100wpc@16, 200wpc@8, 400wpc@4, 800wpc@2 ) on the bottom tightens up the transient performance and control of the bass along with significant headroom. Just all around a better sound..

 

[Swerd]

I put my RX-V863 on my repair bench and can tell you that the Yamaha meets it's PUBLISHED specs as per the FTC requirements.

When all channels are driven it is NOT 105 wpc... it does drop to about 40-42 wpc.

Thanks for that info . It agrees with what Sound and Vision published.

 

[3db]

I also have a Yamaha RX-V863 and am also a retired sr. repair audio tech and having repaired 10's of thousands of amps/receivers over the years of all types and power levels up to several 1000wpc.. I put my RX-V863 on my repair bench and can tell you that the Yamaha meets it's PUBLISHED specs as per the FTC requirements... but you have to understand how that is arrived... and when all channels are driven it is NOT 105 wpc... it does drop to about 40-42 wpc...

All that test shows is how aggressive the protection circuit is in limit the AVR's power delivery. Nothing more. I find the ACD test not very useful in determining real life power requirements and I would never use the ACD test to compare AVR power delivery across manufacturers. Ywo channel test definatetly but not ACD.

 

[surveyor]

I Bi-Amp my front speakers with my Denon AVR-4520ci. I set the active subs - two each 15 " crossover at 80 Hz. I use Infinity Beta 50's for the front, Infinity Beta 360 for the center and 4 each Infinity IL 10s for the surrounds and surroundbacks. I use the Denon DBT-3313UDCI as a source via Denon Link. This is my living room setup. I think the bi-amping makes for better control of the Beta 50's.

 

[Bob Nagy]

I have a modest system in my bedroom I use for 2 channel listening which consists of a Sony STR DN1050 AVR (hope to get a tv and surround in there eventually) and an Onkyo single disc CD player. The Sony also plays high resolution FLAC files off a USB, as well as ALAC from AirPlay. I currently have Wharfedale Diamond 220 speakers (the Jade 3's are paid for and awaiting shipping due to backorder!) that have two sets of binding posts and there is a bi-amp option on the Sony AVR. I started out using single wire 12 AWG cables and they sounded OK for inexpensive speakers, pretty much what I expected based on the positive revirews. After a two week "break-in" period I noticed a slight improvement in the sound, who knows could just be my ears getting used to them. After that time I then bi-amped the speakers and I noticed an immediate, marked improvement in the sound. I'm sold on the idea, at least with these speakers. I will go through the same process with the Jade 3's once they finally get here, can't wait...

 

[gene]

 

[highfigh]

I have a modest system in my bedroom I use for 2 channel listening which consists of a Sony STR DN1050 AVR (hope to get a tv and surround in there eventually) and an Onkyo single disc CD player. The Sony also plays high resolution FLAC files off a USB, as well as ALAC from AirPlay. I currently have Wharfedale Diamond 220 speakers (the Jade 3's are paid for and awaiting shipping due to backorder!) that have two sets of binding posts and there is a bi-amp option on the Sony AVR. I started out using single wire 12 AWG cables and they sounded OK for inexpensive speakers, pretty much what I expected based on the positive revirews. After a two week "break-in" period I noticed a slight improvement in the sound, who knows could just be my ears getting used to them. After that time I then bi-amped the speakers and I noticed an immediate, marked improvement in the sound. I'm sold on the idea, at least with these speakers. I will go through the same process with the Jade 3's once they finally get here, can't wait...

In a two week period, most people are exposed to many audio stimuli that are able to alter their hearing acuity. This can be loud music, loud cars/trucks, fire alarms, squealing brakes, driving with the window open- the list continues.

The difference between bi-amping is in headroom and, as Gene commented in his videoa little bit of extra output.

However, if the crossover is used for the upper range, it can reduce modulation from extremely low frequencies when the speakers are a full-range system and bass pedals or synth is the source. I was listening to some pipe organ music over the weekend and clearly heard modulation in the mid-range. The longest pipe in that organ is 64', so the low end is capable of extremely low frequencies.

http://www.boardwalkhall.com/arena-information/the-restoration-project

 

[AcuDefTechGuy]

One is a partially worthless and the other is totally worthless.

 

[highfigh]

One is a partially worthless and the other is totally worthless.

Yup- decent wire gauge and let 'er rip.

 

[Paul Lane]

I have an interesting set up, Tri-Wired and Bi-amped at each Loudspeaker.
And I used all MonoBlocks. Each speaker has 3 hand built crossovers. XLO speaker wire all around and a Marantz solid state Mono on the bass, and a Kavent (Vincent) Tube Hybrid Monoblock with 2 taps, one for the Focal Utopia Mid and the other for the Tweeter. Running it from a Dared Tube Preamp. Add in 2 subwoofers and it a MonoBlock party allaround. No Crosstalk here.

 

[AcuDefTechGuy]

I have an interesting set up, Tri-Wired and Bi-amped at each Loudspeaker.
And I used all MonoBlocks. Each speaker has 3 hand built crossovers. XLO speaker wire all around and a Marantz solid state Mono on the bass, and a Kavent (Vincent) Tube Hybrid Monoblock with 2 taps, one for the Focal Utopia Mid and the other for the Tweeter. Running it from a Dared Tube Preamp. Add in 2 subwoofers and it a MonoBlock party allaround. No Crosstalk here.

As long as they are ACTIVELY bi-amp and the custom hand-built XO are better than the original XO, that's all good.