Why can some receivers only output rated power at 1 khz? (1 Viewer)

[AaronMK]

When I was looking for a receiver, I was told that "X watts x 5 at 1 khz" vs. "X watts x 5 at 20hz - 20khz" was a very big distinction; that receivers with a power spec rated at only 1khz are usually not nearly as powerful over the 20hz-20khz spectrum.

I was just curious as to why a receiever capable of giving its rated power at 1 khz would not be able to give its rated power at other frequencies.

Thanks for any info.

 

[matthew_rm]

Because the amps are crap, and the company (technics, Kenwood) don't want you to kno that. Same with THD..stuff like 0.2% @1kz at 100W 1 ch. driven, ect....

 

[John Garcia]

Basically, the amp can put out it's rated power at an easily driven frequency. When you start to drive lower frequencies, more current will be drawn (depends on driver design, size, enclosure type, etc...). When an amp rated like this is tested at the 20Hz range, it may only produce a fraction of the power compared to the rating at 1Khz, thus these amps will likely underperform during very dynamic passages, such as heavy effects scenes in movies.

 

[Bob McElfresh]

Aaron - nothing in this hobby is linear.

It takes more power to produce a low-frequency sound than a high frequency one.

(Thats why we have self-powered subs, but not self-powered tweeters).

While you CAN say a receiver will produce 80 watts per channel, this is a over-simplification.

Some less-than-repuitable companies create a receiver that produces XX watts at 1 Khz and dont tell you that the power drops off a lot below that. But they get to put their "black-box" on the same shelf & price as Dennon, Yamaha, Onkyo units that also produce XX watts.

Power numbers are a whole issue. It's just very hard to boil it down to a single number unless you set a limit on about 4 other things. Check the Basics area because I think the Primer has a good description.

 

[ThomasL]

It's also important to note that most receivers in the price range we're talking about do not tell you the power rating when all channels are driven at once. But how much current you actually draw is really going to depend on your usage. If you have a small room, don't listen at ear-splitting reference levels and have smaller booshelf-type speakers and a powered sub with receiver crossover in the 80-120Hz range, then you may come nowhere near drawing all the power the receiver's amps can dish out.

cheers,

--tom

 

[AaronMK]

Thank you very much for the replies.

I guess what really confuses this: When people say that an amp becomes less powerful as it drives lower frequencies, it doesn't seem very differnt from someone saying that an engine loses cylinders if it pulls a heavier load. Sure, the vehicle may not be able to accelerate as quickly pulling a heavier load, but the engine itself would not become less powerful.

Thanks for any additional info.

 

[Earl Simpson]

This is great stuff off of Andrews & Phils sites.
http://www.geocities.com/Area51/Holl...1/ratevsac.htm
B & K AVR202 105w 0.09% 112 0.16% -68.9 dB
Jan-01 B & K AVR307 150w 0.09% 138 0.04% -72.3 dB
Nov-98 DENON AVR-2700 80w 0.05% 71 0.03% -72.7 dB
Dec-01 DENON AVR-2802 91w x 6 0.05% 74 (61 x6) 0.04% -73.3 dB
Dec-99 DENON AVR-3300 105w 0.05% 83 0.033% -73.3 dB
May-01 DENON AVR-3801 105w x 7 0.05% 92 (85 x6) 0.039% -75.0 dB
May-00 DENON AVR-4800 125w 0.70% 148 0.036% -74.4 dB
May-99 DENON AVR-5700 140w 0.70% 125 0.031% -74.1 dB
Dec-00 DENON AVR-5800 170w x 7 0.05% 138 x 5 0.037% -74.7 dB
Jun-01 Harmon Kardon AVR 510 70w 0.07% 74 0.05% -69.8 dB
JUL/AUG 00 Harmon Kardon AVR7000 100w 0.07% 113 0.03% -76.5 dB
Oct-99 JVC RX-1028V 100w 0.08% 67 0.20% -71.2 dB
Nov-00 JVC RX-8000V 100w 0.08% 68 0.23% -66 dB
Oct-01 JVC RX-DP10V 120w x 7 0.02% 104 0.052% -69.4 dB
Dec-98 KENWOOD VR-2080 100w 0.70% 50 0.02% -69.3 dB
Sep-98 KENWOOD VR-209 100w 0.70% 63 0.03% -75.6 dB
JUL/AUG 99 KENWOOD VR-307 100w 0.70% 48 0.05% -69.8 dB
Oct-00 KENWOOD VR-410 100W n/a 44**** n/a -65.7 dB
FEB/MAR 00 KENWOOD VR-3100 100w 0.06% 46 0.04% -71.0 dB
Jun-00 KENWOOD VR-4700 100w 0.06% 97.3 0.036% -73.9 dB
Sep-01 KENWOOD VR-5900 130w 0.06% 110 0.034% -74.3 dB
JUL/AUG 99 MARANTZ SR-18 140w n/a 119 0.05% -74.3 dB
FEB/MAR 00 MARANTZ SR-19 110w 0.05% 88 0.03% -75.5 dB
Nov-01 MARANTZ SR7200 105w x 6 0.05% 29 (27 x6) 0.077% -66.3 dB
Jan-01 MARANTZ SR-14EX 140w 0.05% 144 0.02% -75.2 dB
Jan-99 NAD T770 70w 0.08% 67 0.10% -70 dB
JUL/AUG 99 ONKYO TX-DS474 55w 0.08% 49 0.07% -66 dB
Dec-98 ONKYO TX-DS555 70w 0.08% 70 0.04% -71.8 dB
Sep-99 ONKYO TX-DS575 70w 0.08% 71 0.06% -71.9 dB
Nov-00 ONKYO TX-DS575X 70w 0.08% 70 0.07% -69.1 dB
JUL/AUG 01 ONKYO TX-DS696 100w 0.08% 46 0.02% -73.3 dB
Sep-00 ONKYO TX-DS989 130w x 7 0.05% 126 x 5 0.044% -73.0 dB
FEB/MAR 00 ONKYO TX-DS777 105w 0.08% 92 0.03% -75.2 dB
Oct-00 OUTLAW Audio 1050 65w*** 0.05% 62 x 5 0.074% -68.1 dB
Apr-00 PHILIPS FR960 60w 0.70% 34 0.04% -72.1 dB
Nov-00 PHILIPS FR975 100w 0.70% 63 0.05% -70 dB
Nov-99 PIONEER Elite VXS-24TX 90w 0.09% 76 0.04% -74.3 dB
JUL/AUG 99 PIONEER VSX-D498 70w 0.80% 61 0.04% -73.1 dB
Jan-01 PIONEER VSX-D39TX 120w 0.09% 88 0.06% -70.4 dB
FEB/MAR 02 PIONEER VSX-D49TX 130w x 7 0.09% 148 (144 x6) 0.03%/0.04% 4 ohms -75.3 dB
Dec-01 PIONEER VSX-D850S 110w x 6 1.00% 67 (59 x6) 0.052% -70.0 dB
Apr-02 Rotel RXS-1065 100w 0.05% 106 0.03% -71.1 dB
Oct-98 SHERWOOD AM-9080 120w 0.05% 108 0.01% -72.5 dB
Mar-02 SHERWOOD R-963R 140w x7 0.7% 106 (99 x6) 0.05/0.05% 4 ohms -75.7 dB
Apr-99 SHERWOOD RVD-6090R 45w 0.20% 46 0.069% -70.4 dB
Oct-00 SHERWOOD RD-7106 100W n/a 52 n/a -70.2 dB
Dec-01 SONY STR-DB1070 100W x 6 0.09% 31 (31 X6) 0.058% -65.2 dB
Oct-98 TECHNICS SF-DX6 100w 0.90% 80 0.084% -68 dB
Dec-99 Vantas DPA-P87 100w x 3 0.05% 83 x 3 0.13% -65 dB
Jun-98 YAMAHA DSP-A1 110w 0.04% 116 0.036% -73 dB
May-00 YAMAHA RX-V1 110w 0.015% 104/99 watts** 0.03% -80.5 dB
FEB/MAR 99 YAMAHA RX-V795 85w 0.04% 85 0.053% -72.6 dB
FEB/MAR 01 YAMAHA RX-V1000 100w 0.04% 78 0.071% -68.1 dB Sur / -75 dB F & C
Jan-02 YAMAHA RX-V1200 80w x 6 0.04% 50 (47 x6) 0.04%/0.04% 4 ohms -74.2 dB