[Yeto]

What would be the best way to compare separate component home theater sound system watts versus HTIB system watts given the way (rms, peak power, etc.) different companies rate wattage?

I just finished reading an article -- bittersweet.ondragonswing.com/005615.html -- that, generally speaking, says that most HTIB systems use class AB amps and that a class AB amps output is 50% efficient. The article goes on to say to calculate the power draw numbers of the amp in watts and divide by 2 to get the approximate true power output of a HTIB system when comparing to a separate component system.

I was wondering if the experts on this forum would agree with the article?

Thanks,
Yeto

[FeisalK]

First of all I'd say that these days most if not all HTiBs use class-D amps, or they wouldn't be able to make them that slim/small (class A/B amps need huge heat sinks to dissipate heat because they are inefficient)

Denon (Tripath), Panasonic (TI Equibit), Samsung, Sharp (1-bit), Sony (S-master), Yamaha (proprietary) all use class-D amps in their HTiBs (these are the ones that have a DVD receiver unit)

As far as power ratings are concerned - years before the HT boom, people were buying boom boxes which boasted 1000W Peak Music Power Output. Boomboxes = HTiBs.

Also check this article out : Product Managing Receiver Platforms & Power Ratings

A note about the power consumption/draw rating: quote this TI document (pdf)

Quote:

Because of the dynamic nature of music, when delivering music to a speaker there is a dramatic reduction in the average power consumption—a peak to average power range of more than 20 dB is normal—so a power supply that can deliver the maximum output power continuously is unnecessary. In fact, a good compromise is 1/8 of full power. The dashed horizontal line in Figure 4 is the current corresponding to 1/8 of the maximum power output level (6.25-W output power), but the PSU needs to be capable of delivering the peak power required.

A typical music CD requires 12 dB to 15 dB of dynamic headroom above the average power output to pass the loudest portions without distortion. This is a good fit with the compromise of a continuously rated power supply having 1/8 power output. According to CIRSP22, 1/8 full power is the level at which testing is to be carried out during EMI qualification.

what's this mean? you can't rely on power consumption rating to calculate full power output.

[HT-EXT]

I would start with the RMS value and go from there. Peak is just a sugar coated rating that the system will not be capable of reaching without plenty of distortion to go with the 100w per channel peak rating. Also note the ratings as they are listed 100w x 5 (1kHz @ 1% THD). This means all five speakers will be capable of 100w at 1kHz with total harmonic distortion at 1% which to me is unacceptable. First the rating is not covering the full spectrum(20Hz-20kHz) and the THD is to high just so they say it puts out 100w. My way of thinking is to reduce the number given by a certain percentage to allow for full range operation and less THD. For example to cover to spectrum reduce the 100w by 25% this will give you about 75w and that is being generous. Next reduce 75w down another 10% to 15% to eliminate some THD. The final results 50w to 60w x 5 (50Hz-15kHz @ 0.1% THD) for HTIB and that is being very generous with the numbers. The first thing I would look at is power per channel versus range versus THD. Power output should be around 75w to 100w per channel (20Hz to 20kHz @ 8 ohm). THD should be 0.1% or lower but in HT this is some what hard to find without putting out the "BIG BUCKS". Hope this helps.

HT-EXT

[Arthur S]

Yeto

In my humble opinion, it doesn't really matter how they rate power output. All of the better HTIBs have sufficient power to drive their speakers to a pretty high volume level without audible distortion. If you want the rankings of HTIBs please send me a private message. There are some good values from ~$250 and up...

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