Stereo vs 5.1 sound, AVR vs 2 Chn Amp, CDP vd DVDP

[linny]

Hi folks
I have always come across this statement that 5.1 is not good from listening to stereo music, but was unable to understand why. I am a newbie to this so have queries regarding the same.

1. Music CD/DVD are generally recorded in stereo format. So when we play music, does the AVR further synthesize the music and split it for 5.1 surround support ?
OR do the 2 front L/R speakers (+ subwoofer) from the 5.1 only provide stereo output.

2. Can anyone provide technical details as to why stereo speakers are better than 5.1 speakers ? In case 5.1 can produce surround sound which would give a 3d music experience, how can one say Stereo speakers are better ?

Pardon my ignorance.

Thanks
Linny

 

[hemantwaghe]

Re: Why Stereo Speakers are better than 5.1 for Music ?

You first hear it on differt setups and then trust your ears only!

 

[vivek.saikia]

Re: Why Stereo Speakers are better than 5.1 for Music ?

Hi folks
I have always come across this statement that 5.1 is not good from listening to stereo music, but was unable to understand why. I am a newbie to this so have queries regarding the same.

1. Music CD/DVD are generally recorded in stereo format. So when we play music, does the AVR further synthesize the music and split it for 5.1 surround support ?
OR do the 2 front L/R speakers (+ subwoofer) from the 5.1 only provide stereo output.

2. Can anyone provide technical details as to why stereo speakers are better than 5.1 speakers ? In case 5.1 can produce surround sound which would give a 3d music experience, how can one say Stereo speakers are better ?

Pardon my ignorance.

Thanks
Linny

Hi Linny,

I will put it in this way. You don't listen to a live orchestra, sitting in the middle of the stage surrounded by the musicians; rather you enjoy the most when you are sitting on the audience side and the band/orchestra is playing in front of you, on the stage.
I Hope that clarifies your doubt.

Cheers!
Vivek

 

[arj]

Re: Why Stereo Speakers are better than 5.1 for Music ?

1. Most music has been recorded as 2 channels..hearing it in a 5.1 would only be due to some electronic simulation and this will cause some loss in the "purity" of the recording
2. For a fixed budget the quality of a 5 speakers and a sub would be much lesser to a similiar 2 channel setup...or put another way..for the same money you can buy much more higher quality equipment

many others (as above) but the above two highlight the main to points for me....quoting something i read many ears back "I have only 2 ears so need only 2 speakers )

 

[avidyarthy]

Re: Why Stereo Speakers are better than 5.1 for Music ?

Exactly .... thats the best description, Vivek.

The sound hits you in the face .... stereo gives a more realistic feeling of a concert in progress, unlike the 'surround effect' created by 5.1.

But, frankly, me too likes the 5.1 thing more than stereo for SOME music. Have noted separations to be superior in 5.1 for group 'instrumentals'. But, thats again subjective. Maybe, my stereo speakers are not in that league.

 

[venkatcr]

Re: Why Stereo Speakers are better than 5.1 for Music ?

It is the not the speakers per se that make the difference. The same set of speakers can be used both for a two channel setup as well as the fronts for a 5.1/7.1 set up.

When you do this, would the same speakers sound different? What are the factors the decide the difference? Actually there are two:

1. The player. A CD player is optimised for two channel music. It is built that way. It has a laser drive that can extract data better, has optimised and high quality DAC, and just enough electronics needed for Redbook CD playback. Many players have shielding inside that help reduce noise.

2. The Amplifier. A two channel integrated amplifier, again, is optimised for music. The preamplifier has circuitry that helps take the signals from the CD player and pre-amplify it with least amount of signal loss. It also works towards ensuring that all frequencies (20Hz to 20kHz) are given the same importance. This is critical for hearing music, properly balanced across the frequencies as the musician desired.

Similarly, the amplifier is also built for music. First it is supported by a beefy transformer that is capable of supplying the power needed to handle surges and peaks. Remember, the transformer/power unit handles just two channels. The amplifier circuit, by itself, has various mechanisms built inside such as feedback to avoid distortion. In many amplifiers, the two channels are independently amplified avoiding crosstalk.

Most amplifiers work in the analogue domain, needing lesser electronic circuits. The audio signal travels through a small and elegant path. This allows you to hear the music with pristine clarity.

An DVD Player on the other hand, has multiple tasks to perform. It's most important task is to pick up video, and handle audio in the digital domain. Even if DAC is done in the DVD Player, it is usually of a much lesser quality.

An AVR also has multiple tasks to perform. It has to decode the video, scale the video, decode the audio, and send it to 6 or 8 channels. It has just one power supply. So the power unit has to be ready to supply power to all the 6 or 8 channels of audio as well as the video circuitry. Even if an AVR uses a good DAC, the whole circuitry is optimised for movies and not for music.

In terms of listening in 2 channel or 5.1/7.1, this depends upon the original source. If you take a two channel CD and play it on all 5.1 or 7.1 channels, all you are doing is to repeat the same music on all channels. You are, in effect, overwhelming yourself with music from all sides. Though this may sound good initially, it time, you will end up with ear fatigue. Most important, this was not the intention of the musician and the editor. Music may be recorded with multiple mikes, but it is usually mixed into two channels with the music director/musician carefully listening to each second of the music before the CD is released.

Listening to a true 5.1 audio is a different experience. Here the music has been recorded for 6 channels, and various instruments will he heard from different speakers. The main instrument or singer's voice will always come from the central channel. You should feel as if the music is coming from all sides and you will not be overwhelmed. But remember, a true 5.1 music has to be done that way from the beginning - from playing to recording to editing to releasing of the CD/DVD.

Cheers

 

[sumit_4palz]

Re: Why Stereo Speakers are better than 5.1 for Music ?

Venkat : Great post

Do we get audio recorded in 5.1?

 

[iaudio]

Re: Why Stereo Speakers are better than 5.1 for Music ?

sumit, yes, we do get audio in 5.1. IIRC, the tamil movie Boys OSt was released in 5.1 among many others.

 

[venkatcr]

Re: Why Stereo Speakers are better than 5.1 for Music ?

Unfortunately they becoming rare, but yes, they are available. This comes in a DVD and not a CD.

Cheers

 

[goose]

Re: Why Stereo Speakers are better than 5.1 for Music ?

Venkat - great piece of explanation! I'm getting lesser and lesser ignorant (atleast in this area) day by day, thanks to you an other forum members!

I've got one other doubt that's possibly an extension of the same topic. I may've asked this elsewhere in this forum but haven't got a response.

Now comparing a stereo amp vs a an AVR of similar rating (let's assume 75wpc) you would agree that playing the same 2ch music from the same CD player and played back by the same speakers, the 2ch stereo amp would sound simply far better and feels that the speakers are driven more 'hard' by a stereo amp than a receiver.

Why does one hear this difference inspite of both the set-up being rated 75wpc.

Just to add, an AVR typically rate all their channels same (say 75wpc) however it's only the fronts that are fed with max power. If one were to connect a higher wattage speaker to the surround backs the sound is quite tinny and weak. So what does this 75x7 really mean then?

TIA....G

 

[bansal98]

Re: Why Stereo Speakers are better than 5.1 for Music ?

With all due respect, I have a couple of objections to these statements.

1. The player. A CD player is optimised for two channel music. It is built that way. It has a laser drive that can extract data better, has optimised and high quality DAC, and just enough electronics needed for Redbook CD playback. Many players have shielding inside that help reduce noise.

I don't think this is completely true. The laser drive is the same in all CD players. What could be different is the amount and quality of error correction. That too is valid only in the case of scratched CDs. You are right about the DAC and other electronics though it is only applicable for somewhat high-end CD players.

2. The Amplifier. A two channel integrated amplifier, again, is optimised for music. The preamplifier has circuitry that helps take the signals from the CD player and pre-amplify it with least amount of signal loss. It also works towards ensuring that all frequencies (20Hz to 20kHz) are given the same importance. This is critical for hearing music, properly balanced across the frequencies as the musician desired.

Similarly, the amplifier is also built for music. First it is supported by a beefy transformer that is capable of supplying the power needed to handle surges and peaks. Remember, the transformer/power unit handles just two channels. The amplifier circuit, by itself, has various mechanisms built inside such as feedback to avoid distortion. In many amplifiers, the two channels are independently amplified avoiding crosstalk.

From a technical perspective, there is no such thing as an optimized-for-music amplifier. If a stereo amplifier and an AVR both have same power ratings (real RMS values, over the same load and same frequency range), there should be no difference between their output. All AVRs have stereo mode or direct mode for 2-channel listening. I think why most people don't like the AVR for music is because they keep all the other processing engaged. I listen to music on my AVR in direct stereo mode and it sounds great.

Also, the separate amplifiers for separate channels etc are not unique to stereo amplifiers. They are also present in various AVRs though costly ones (same case as stereo amps).

Most amplifiers work in the analogue domain, needing lesser electronic circuits. The audio signal travels through a small and elegant path. This allows you to hear the music with pristine clarity.

Shouldn't this be true for both stereo amps and AVRs?

An DVD Player on the other hand, has multiple tasks to perform. It's most important task is to pick up video, and handle audio in the digital domain. Even if DAC is done in the DVD Player, it is usually of a much lesser quality.

A cheap DVD player might have inferior DAC and other electronics but that is only because of the cost. If you take optical out from a DVD player and do the conversion elsewhere, it would sound just as good.

An AVR also has multiple tasks to perform. It has to decode the video, scale the video, decode the audio, and send it to 6 or 8 channels. It has just one power supply. So the power unit has to be ready to supply power to all the 6 or 8 channels of audio as well as the video circuitry. Even if an AVR uses a good DAC, the whole circuitry is optimised for movies and not for music.

If you are playing 2-channel audio in an AVR and have done the settings correctly, it should not sound any different from a stereo amplifier (of the same specs).

Just my thoughts. No disrespect meant to anybody, least of all to Venkat sir.

 

[goose]

Re: Why Stereo Speakers are better than 5.1 for Music ?

If you are playing 2-channel audio in an AVR and have done the settings correctly, it should not sound any different from a stereo amplifier (of the same specs).

Oooh Bansalji - I beg to differ on this one comment. I do not know about the other areas you've commented, maybe somene like Venkat himself can answer it. But this one comment where the AVR and Stereo-amp sounding alike for a given wattage (I assume that's what you meant by spec?), I guess I've heard different.

In my personal experience, the stereo-amp sounds way too clear and musical and has an absolute 'control' over the way speakers deliver the sound. I don't know if the differennce in damping factor of the amp vs AVR is what's causing this difference in sound, but it's there and for real. Again I wouldn't risk too much in saying that the difference in sound quality is day and night!

G

 

[bansal98]

Re: Why Stereo Speakers are better than 5.1 for Music ?

Oooh Bansalji - I beg to differ on this one comment. I do not know about your the areas you've commented, maybe somene like Venkat himself can answer it. But this one comment where the AVR and Stereo-amp sounding alike for a given wattage (I assume that's what you meant by spec?), I guess I've heard different.

In my personal experience, the stereo-amp sounds way too clear and musical and has an absolute 'control' over the way speakers deliver the sound. I don't know if the differennce in damping factor of the amp vs AVR is what's causing this difference in sound, but it's there and for real. Again I wouldn't risk too much in saying that the difference in sound quality is day and night!

G

I also said that AVR has to be set properly (all processing off, using direct stereo mode, set all surround channels to 'none', set sub-woofer to 'no' if you don't have it etc.). Also, tube amps have way lower damping factor than solid-state amps and they still sound great.

 

[shailenderb]

Re: Why Stereo Speakers are better than 5.1 for Music ?

I also said that AVR has to be set properly (all processing off, using direct stereo mode, set all surround channels to 'none', set sub-woofer to 'no' if you don't have it etc.). Also, tube amps have way lower damping factor than solid-state amps and they still sound great.

A 60-watt per channel stereo amp sounds far better than a 130-watt per channel AVR (set to play in direct mode, disengaging all othe processing) with the same speakers (of around 130 watts) and with the same source and same music.

This is my personal experience. Am not really conversant with all the technical details being discussed.

I suppose Venkat is right for practicial purposes while Bansal may be correct theoretically.

Would like to hear from both these and other experts on this.

Shailender

 

[bansal98]

Re: Why Stereo Speakers are better than 5.1 for Music ?

A 60-watt per channel stereo amp sounds far better than a 130-watt per channel AVR (set to play in direct mode, disengaging all othe processing) with the same speakers (of around 130 watts) and with the same source and same music.

This is my personal experience. Am not really conversant with all the technical details being discussed.

I suppose Venkat is right for practicial purposes while Bansal may be correct theoretically.

Would like to hear from both these and other experts on this.

Shailender

You need to compare the real power rating specified at identical load and identical frequency range and comparable THD values. AVRs are known to greatly exaggerate their power ratings but they also specify the FTC ratings in the small print (which is what we are interested in).

 

[elangoas]

Re: Why Stereo Speakers are better than 5.1 for Music ?

What is FTC ratings ? Could u plz explain...

 

[bansal98]

Re: Why Stereo Speakers are better than 5.1 for Music ?

What is FTC ratings ? Could u plz explain...

Here you go:
How to Compare Amplifier Power Ratings by Patrick Quilter

Home Theater: Decoding Amp Power Specs

These explain it much better than I could.

 

[venkatcr]

Re: Why Stereo Speakers are better than 5.1 for Music ?

I don't think this is completely true. The laser drive is the same in all CD players. What could be different is the amount and quality of error correction. That too is valid only in the case of scratched CDs. You are right about the DAC and other electronics though it is only applicable for somewhat high-end CD players.

At the outset, I was comparing the laser drive of a CD player with that of a DVD Player. A DVD has a much larger number of pits that the laser has to read. Essentially, the laser of a CD Player has an easier task, and that is what I meant when I said it is optimised for music. I can give you detailed technical diagrams and information on the differences between the two if you are interested. The width of the laser beam, the motors used for moving the head, the track/sector information are all different.

In addition, though you may be able to make a CD Player by buying a ready made drive from Philips, Teac or other companies, many companies have started making their own drives to improve the quality. Companies such as Emotiva and Cyrus have designed from scratch their own drives, and believe me, these are far better than your run of the mill drives. Laser drives are NOT the same even for CD players. Though the technology could be the same, the way they are designed and built make a huge difference.

From a technical perspective, there is no such thing as an optimized-for-music amplifier. If a stereo amplifier and an AVR both have same power ratings (real RMS values, over the same load and same frequency range), there should be no difference between their output. All AVRs have stereo mode or direct mode for 2-channel listening. I think why most people don't like the AVR for music is because they keep all the other processing engaged. I listen to music on my AVR in direct stereo mode and it sounds great.

Have you heard of Class A amps? Have you heard of feedback mechanism? Have you heard of SNR? Have you heard of THD? Have you heard of decoupling? Have you heard of Op-amps? Have you heard of tube amps?

You are welcome to think that AVRs and technically the same as a stereo amps, but they are not. At the same price level, for music, a good stereo amp will beat the pants off any AVR. Just one simple statement. An AVR is not designed for music. It is designed for movies. Yes, since it is an amplifier, it can also amplify music source. But it is not meant to do that. Stereo mode and Direct mode just cut off the power to the video and other circuitry in addition to gimmicks such as shutting of the display, but the internal amplification design and implementation remain the same.

Power ratings (RMS or otherwise) mean nothing. The amount of power needed or used is a factor of the speaker specifications more than the amp. Most designers of stereo amps work hard to control the kind of sound that flows and with what power over the speakers.

Also, the separate amplifiers for separate channels etc are not unique to stereo amplifiers. They are also present in various AVRs though costly ones (same case as stereo amps).

Again this is a factor of the cost. In terms of channel isolation alone, you would get channel isolation is a stereo amp costing say 30 to 50K. To get channel isolation in an AVR you have to go beyond 1 or 1.5 lakhs.

Shouldn't this be true for both stereo amps and AVRs?

Most stereo amps work ONLY in the analogue domain. They expect analogue inputs and their only job is amplification. ALL AVRs accept both analogue and digital signals. So they do have DAC circuits. Yes, the final amplification is analogue. But, it is an accepted fact that the more processing you do in a near-field, the more the chances of noise.

A cheap DVD player might have inferior DAC and other electronics but that is only because of the cost. If you take optical out from a DVD player and do the conversion elsewhere, it would sound just as good.

If it were so simple, why would Oppo spends millions of dollars designing a separate audio circuitry in their DVD Players? Just take the digital out from a Pioneer DVD Player, and compare it with the output of say a Marantz CD Player. You WILL hear audible differences in sound signature. I do this every day.

Cheers

 

[venkatcr]

Re: Why Stereo Speakers are better than 5.1 for Music ?

Now comparing a stereo amp vs a an AVR of similar rating (let's assume 75wpc) you would agree that playing the same 2ch music from the same CD player and played back by the same speakers, the 2ch stereo amp would sound simply far better and feels that the speakers are driven more 'hard' by a stereo amp than a receiver.

Why does one hear this difference inspite of both the set-up being rated 75wpc.

The power rating of an amplifier has to be matched with the input sensitivity and power handling capacity of the speakers. The higher the sensitivity, the easier it is to drive the speakers. Many speaker manufacturers advertise huge specifications - (40 to 250 watts) but build a protection circuit inside through resistors. In effect, these resistors act as a wall to the power being supplied and do not go to the drivers at all. If you remove the resistors, these speakers will distort at half their stated power ratings.

A speaker essentially sucks power from the amp. If too much power is sucked, the amp could clip - run out of energy. To overcome this, stereo amps have larger power supplies that can deliver the power needed by the speakers. This also helps when there is change in the peaks and surges in the music. When you blow a trumpet for a few seconds, for example, the amplifier should be able to instantly deliver the required power. This is done by a combination of higher power unit as well as high quality capacitors.

Just to add, an AVR typically rate all their channels same (say 75wpc) however it's only the fronts that are fed with max power. If one were to connect a higher wattage speaker to the surround backs the sound is quite tinny and weak. So what does this 75x7 really mean then?

This is again a trick played by all manufacturers. If you read the specs carefully, they will say '75 watts per channel, 2 channels driven at 1000 Hz into 8 ohms'. Essentially, they will use a test tone that sends a continuous 1000Hz signal to test the power rating. And they will do this for just two channels. Though they may have 7 amplifiers all rated at 75 watts, the actual usage they expect at any time is only 2 or three channels. In a DVD, 80% of the audio is sent to the front three channels. If you drive ALL the 7 channels at the same time with the same frequency signal, the power of all the amplifiers will fall dramatically.

The amplifier power rating is a factor of the power supply. To get 75 watts into ALL seven channel continuously, the AVR may need 7 power supply units. But since you will never come across a movies that drives all 7 channels, most AVR design power supplies that can drive 2 or 3 channels at a time.

Cheers

 

[bansal98]

Re: Why Stereo Speakers are better than 5.1 for Music ?

@Venkat:

I would state my position as follows:

We are not comparing a stereo amp costing 30k with an AVR costing 30k. If that would have been the case, the amp would win hands down. My point of comparison is the power rating. If two amplifiers have the same power rating, specified over the same frequency range and impedance and with same THD figures, they would sound the same. One can be a dedicated amp and the other can be an AVR. This assumes that the signal is not being modified by doing any processing etc. All this is, of course, in analog domain.

A stereo amp can still sound better even if all of the above conditions are met if it has better components. Again, that is not my point of comparison. The contention is whether AVRs are inherently inferior to dedicated amps. An AVR with same components as that of the dedicated amp will sound the same. It might be more costly than the amp but price is not the contention here.

Regarding DVD players vs CD players, my opinion is that if you are not doing any processing on the data from the moment it is read till it reaches the digital out, it should sound the same. That is the whole point of having digital data. Please note that I am talking about digital out and pristine CDs. A better DAC with excellent jitter correction will have better sound but that comes after the digital out.

Update: All this assumes that we are level matching to 0.1dB.