RMS Sound Output

  SURVEY 14:15 28 Mar 2006

I am trying to compare the specifications of two TV's and as happens so often even with the same retailer they will insist on not using consistent comparison methods.

Can anyone inform me what the diffrence in output is between 6watts RMS and 2x5watts RMS?

  amonra 14:44 28 Mar 2006

The 6watt output is probably the quoted mono output,(could be the combined power output of both channels) whilst the 2X5watt is the individual stereo output.
I would have thought that the 2X5 watt would be the better of the two ??? Pays your money takes your pick.

  SURVEY 14:47 28 Mar 2006

Amonra - Thanks for your reply. I shall tick the box but if anyone else has an opinion please continue to post.

  oresome 19:35 28 Mar 2006

Perceived loudness levels are on a logarithmic scale.

For a sound to be twice as loud, you require a 10dB increase in power which approx equates to a ten fold increase in power from say 5 watts to 50 watts.

I doubt you'll notice much difference between the two specs, assuming the o/p remains undistorted in both cases.

  Arnie 23:47 30 Mar 2006

Also look at the signal distortion levels at the full rated output.

Most low to medium priced TVs fall well short of even a low end hifi amplifier's spec.

To the untrained ear around 0.1% at the full rms output should be acceptable.

An audiophile would expect something way above this quality.

Anyway to me, television viewing is about good program content and picture quality. Most moderately priced TV's will give an acceptable picture if supplied with a good signal to noise ratio.

This is purely my personal viewpoint.

  SURVEY 09:26 01 Apr 2006

Thank you one and all for your replies.

  Stuartli 00:02 02 Apr 2006

>>For a sound to be twice as loud, you require a 10dB increase>>

+3dB if you double the power and -3dB if you halve the power.

The "specification" to avoid is PMPO which is a neat way/trick to make even five watt speakers appear able to fill the house with music; RMS figures are the most reliable guide.

  DieSse 09:55 02 Apr 2006

Perceived "loudness" depends as much or more on loudspeaker efficiency as amplifier power output.

Generally speaking (though there are exceptions) the better the quality of the speaker, the lower the efficiency (I did see an article many, many moons ago, for a pair of folded horn speakera built into the alcoves either side of a fireplace, which could reputedly "blow your socks off" with 0.5wattt (yup ½watt RMS input)

So to answer your question - either could be better, or louder - why not listen to them both!

  Stuartli 12:11 02 Apr 2006

You may be thinking of impedence (ohms) - most speakers are eight ohms but speakers of two or four ohms will provide higher sound levels for a given power (wattage) supply.

The lower the ohms figure the higher the sound levels.

My best mate, who runs an independent audio/visual/appliances out let, has often installed PA systems in local hotels, commercial premises etc.

The particular amplifier he uses for the setup is 15w per channel, but everyone is to hear both speech and music absolutely clearly and at levels that will surprise you...:-)

In my case, the 30w per channel NAD 7300 tuner/amplifier that I've been using since 1979 is capable of driving two, four and eight ohm speakers.

  Stuartli 12:48 02 Apr 2006

To clarify the above a little, the lower the speakers' ohms figure, the less amplifier wattage required for a given sound level...

  DieSse 15:52 02 Apr 2006

Yes, I know about impedance and the effect that can have on sound output - efficiency is a different thing altogether. Sealed box loudspeakers, for instance, are less efficient than ported box speakers, doe to the back air pressure inside the box, which dampens cone movements.

The speakers I mentioned above, used a folded horn - which greatly amplifies their efficiency.

A little write up here which refers to efficiency click here If you google for - loudspeaker efficiency - you'll gets lots of references.

I'm not sure it's terribly relevant to TVs, but I thought I would mention it anyway :-))

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