Rating at 1kHz vs 20Hz-20kHz
RandyBox
Posts: 125
Never knew there was this sort of discrepancy in the way different amp manufacturers rate their amps.
Just ordered an H/K 347 and it says:
AVR 347
7.1-Channel A/V Receiver With HDMI Switching and Audio/Video Processing
385W: 55 watts x 7 (All channels operating at full-rated power), THD <0.07%, 20Hz - 20kHz into 8 ohms
665W: 95 watts x 7, THD <0.07%, @1kHz into 8ohms
That's some difference!
Regards,
Randy
Just ordered an H/K 347 and it says:
AVR 347
7.1-Channel A/V Receiver With HDMI Switching and Audio/Video Processing
385W: 55 watts x 7 (All channels operating at full-rated power), THD <0.07%, 20Hz - 20kHz into 8 ohms
665W: 95 watts x 7, THD <0.07%, @1kHz into 8ohms
That's some difference!
Regards,
Randy
Post edited by RandyBox on
Comments
-
Never knew there was this sort of discrepancy in the way different amp manufacturers rate their amps.
Just ordered an H/K 347 and it says:
AVR 347
7.1-Channel A/V Receiver With HDMI™ Switching and Audio/Video Processing
385W: 55 watts x 7 (All channels operating at full-rated power), THD <0.07%, 20Hz - 20kHz into 8 ohms
665W: 95 watts x 7, THD <0.07%, @1kHz into 8ohms
That's some difference!
Regards,
Randy
When they went to multi-channel from stereo, the rules went out the
window. The old 2 channel standards for RMS, if I remember right, both
channels driven for one hour. Now it's any channel one channel at a time
for just a moment. Close enought for HT!"The legitimate powers of government extend to such acts only as are injurious to others. But it does me no injury for my neighbour to say there are twenty gods, or no god. It neither picks my pocket nor breaks my leg." --Thomas Jefferson -
Amp output numbers can be so squed it is terrable. 1kHz is a specific range between 20Hz and 20kHz. 20Hz is the low and 20,000Hz or 20kHz is the high. They are saying that a tone at 1kHz, 1,000Hz the amp can put out 95 watts.
That is so BS to even to say that. They just want to be able to put 95wpc in the specs.Sunfire TGP, Sunfire Cinema Grand, Sunfire 300~2 (2), Sunfire True Sub (2),Carver ALS Platinum, Carver AL III, TFM-55, C-19, C-9, TX-8, SDA-490t, SDA-390t -
Randy, the same FTC regulations for amplifier power numbers are in effect now as have been for many years. Briefly, they require that at least two channels(the manufacturer can specify more) be driven simultaneously at the full rated power continuously for at least five minutes. The frequency range, impedance and % distortion has to be specified.
There are two differences in the 55 watt and 95 watt ratings that you quote. The 55 watt rating is with all channels driven simultaneously at full power and is over the entire 20Hz-20KHz range. The 95 watt rating is at 1KHz, and typically this might be about 10% higher than the 20Hz-20KHz rating, with the 20Hz number usually, but not always, being the frequency that would rate about 10% lower. Also, since the 95 watt rating doesn't specifically state that it's with all channels driven, this is to be understood as being with two channels driven, which also allows for more power per channel.
The 95 watt rating can be viewed as the more realistic of the two when considering actual use in home audio rather than laboratory stress testing. Simultaneous full power on all channels for five minutes isn't something that's even remotely approached in real-life listening. -
Thanks guys... Since I'm very pleased with the AVR147's 40 watts per channel, I should be tickled for a while with the AVR347's 55 watts...
-
But what is the point of saying that it can drive 2 channels at 1kHz at 95 watts. That is so specific and irrelevan specification. Why not give what it can drive into two channels 20Hz to 20kHz. That would be a relevent speification.
It would be like saying that my Carver TFM25 can drive 600 watts in one channel at 1kHz.Sunfire TGP, Sunfire Cinema Grand, Sunfire 300~2 (2), Sunfire True Sub (2),Carver ALS Platinum, Carver AL III, TFM-55, C-19, C-9, TX-8, SDA-490t, SDA-390t -
Thanks guys... Since I'm very pleased with the AVR147's 40 watts per channel, I should be tickled for a while with the AVR347's 55 watts...
I hope you are buying this AVR for the feature upgrades and not the 15wpc. You will not hear a volume difference with an 15 extra watts.
It takes 10x the power to double the volume.Sunfire TGP, Sunfire Cinema Grand, Sunfire 300~2 (2), Sunfire True Sub (2),Carver ALS Platinum, Carver AL III, TFM-55, C-19, C-9, TX-8, SDA-490t, SDA-390t -
Where power is concerned among receivers, H/K is respectable. Now reliability, thats another story...Do you hear that buzzing noise?
-
thuffman03 wrote: »But what is the point of saying that it can drive 2 channels at 1kHz at 95 watts. That is so specific and irrelevan specification. Why not give what it can drive into two channels 20Hz to 20kHz. That would be a relevent speification.
It would be like saying that my Carver TFM25 can drive 600 watts in one channel at 1kHz.
It doesn't say that. It says "95 watts x 7 @ 1kHz"
The complete specs give the 2 channel rating as:
70 Watts per channel, 20Hz 20kHz, @ <0.07% THD, both channels driven into 8 ohms
Regards,
Randy -
thuffman03 wrote: »I hope you are buying this AVR for the feature upgrades and not the 15wpc. You will not hear a volume difference with an 15 extra watts.
It takes 10x the power to double the volume.
Yeah, I wanted one with preamp outputs in case I started playing with amps...
Regards,
Randy -
It doesn't say that. It says "95 watts x 7 @ 1kHz"
The complete specs give the 2 channel rating as:
70 Watts per channel, 20Hz 20kHz, @ <0.07% THD, both channels driven into 8 ohms
Regards,
Randy
Okay. That is better. Sorry but I don't know HK's AVR's any more. My last AVR was the 65.
What I trying to say is why even bother saying 95 watts when it is so specific of a range. It makes it too confusing for people who don't understand.Sunfire TGP, Sunfire Cinema Grand, Sunfire 300~2 (2), Sunfire True Sub (2),Carver ALS Platinum, Carver AL III, TFM-55, C-19, C-9, TX-8, SDA-490t, SDA-390t -
Yeah, I wanted one with preamp outputs in case I started playing with amps...
Regards,
Randy
Power specs can be very misleading, but as long as you have pre-outs you can always add an amp.
What kind of speakers do you have?? -
It doesn't say that. It says "95 watts x 7 @ 1kHz"
The complete specs give the 2 channel rating as:
70 Watts per channel, 20Hz 20kHz, @ <0.07% THD, both channels driven into 8 ohms
Regards,
Randy
Yeah, and I can tell you in real life with real musical content you won't reach that figure either. Specs are a guideline and are analogous to a photo which is a very short moment in time, a snapshot at a specific moment.
There is no such thing as a constant 8 ohm load in real musical content either.
H9"Appreciation of audio is a completely subjective human experience. Measurements can provide a measure of insight, but are no substitute for human judgment. Why are we looking to reduce a subjective experience to objective criteria anyway? The subtleties of music and audio reproduction are for those who appreciate it. Differentiation by numbers is for those who do not".--Nelson Pass Pass Labs XA25 | EE Avant Pre | EE Mini Max Supreme DAC | MIT Shotgun S1 | Puritan Audio PSM136 Pwr Condtioner & Classic PC's | Legend L600 | BlueSound Node3 - Tubes add soul! -
Power specs can be very misleading, but as long as you have pre-outs you can always add an amp.
What kind of speakers do you have??
Monitor 70
Monitor 40
CS2
PSW505
Very happy with the sound, they seem to be getting a really warm sound which in turn gives me a fuzzy feeling... We're all warm and fuzzy here!:p
Regards,
Randy -
You won't have any issues with that setup, IMO. In fact, I would suggest (to the horror of some, perhaps) that it's not entirely certain that adding an external amp would help your true life listening results that noticeably in this case, depending on your requirements, preferences, priorities and listening habits ... amongst other things. YMMV, of course, so do your homework!Monitor 70
Monitor 40
CS2
PSW505
Very happy with the sound, they seem to be getting a really warm sound which in turn gives me a fuzzy feeling... We're all warm and fuzzy here!:p
Regards,
Randy
As for the h/k 147, its ratings were tested in a review by Home Theater Mag, and on the bench, it delivered:
- 67w/ch, all channels driven, vs. 40w/ch stated output.
- 90w/ch, two channels driven, vs. 50w/ch stated output.
To be entirely fair, the bench test was conducted to 0.1% distortion, whereas the sated output is rated at 0.07%, but differences below 0.1% THD are not supposed to be noticeable. To me, this does show that harman/kardon are being more honest that just about 95% of the widely available brands.
The somewhat confusing specifications stated for the 347 may very well be a marketing reaction to other brands making it look as though the 347 is just too weak in output, even though the same review for the the 147 measured the output of two other receivers thus:
- Receiver A: 47w/ch, all channels driven, vs. 100w/ch stated output.
- Receiver B: 48w/ch, all channels driven, vs. 140w/ch stated output.
So, both of these receivers delivered less than half their stated output under the same test conditions as the harman/kardon, whereas the harman/kardon delivered quite a bit more than it's stated abilities. Considering that the other two receivers cost more than twice the h/k (receiver A) and almost four times as much (receiver
I'm not convinced that h/k is the worst offender when it comes to marketing claims vs. reality ... not by any means.
This is the review, from December 2007: http://www.hometheatermag.com/receivers/1107rack/index.htmlAlea jacta est! -
The somewhat confusing specifications stated for the 347 may very well be a marketing reaction to other brands making it look as though the 347 is just too weak in output, even though the same review for the the 147 measured the output of two other receivers thus:
- Receiver A: 47w/ch, all channels driven, vs. 100w/ch stated output.
- Receiver B: 48w/ch, all channels driven, vs. 140w/ch stated output.
So, both of these receivers delivered less than half their stated output under the same test conditions as the harman/kardon, whereas the harman/kardon delivered quite a bit more than it's stated abilities. Considering that the other two receivers cost more than twice the h/k (receiver A) and almost four times as much (receiver I'm not convinced that h/k is the worst offender when it comes to marketing claims vs. reality ... not by any means.
This is the review, from December 2007: http://www.hometheatermag.com/receivers/1107rack/index.html
Now THAT's what I thought. There are some reputable brands who state their power on the 1kHz scale. I think H/K offers that as more of an "Oranges to Oranges" gauge...
Regards,
Randy
