Could someone please give me a quick and dirty explanation? - AVS Forum
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post #1 of 15 Old 03-13-2013, 01:46 PM - Thread Starter
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When I'm looking at the Power Amplifier Section specs for my receiver, this is what I see:

Rated output *THD figures are power amp stage values.

Front L/R 75 W + 75 W
(8 ohms, 20 Hz - 20 kHz, THD 0.08 %)
120 W + 120 W
(6 ohms, 1 kHz, THD 0.7%)

Center 75 W
(8 ohms, 20 Hz - 20 kHz, THD 0.08 %)
120 W
(6 ohms, 1 kHz, THD 0.7%)

Surround L/R 75 W + 75 W
(8 ohms, 20 Hz - 20 kHz, THD 0.08 %)
120 W + 120 W
(6 ohms, 1 kHz, THD 0.7%)

What is this basically telling me? My best guess is that it is explaining a relationship between impedance, power, and frequency response. But I can't quite grasp how it all should be interpreted.

Thank you.
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post #2 of 15 Old 03-13-2013, 02:02 PM
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It tells me they did not want to publish the 20hz to 20khz specs for 6 ohms and 120watt output. smile.gif

As resistance goes down, output goes up, as output goes up so does distortion.
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post #3 of 15 Old 03-13-2013, 02:04 PM
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What I gather is it is capable of 75wpc into an 8ohm load, while driving two channels simultaneously, at full range frequencies. If you drive more than two channels your wpc will reduce.
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post #4 of 15 Old 03-13-2013, 02:22 PM - Thread Starter
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Quote:
Originally Posted by JOHNnDENVER View Post

It tells me they did not want to publish the 20hz to 20khz specs for 6 ohms and 120watt output. smile.gif

It's a Denon... Is that something that they typically don't do? Just to save face?

Maybe I should be specific then, if I may. Any issues with speakers with 6 Ohms impedance, power capacity at 80W nominal / 160W max, FR of 50Hz to 20kHz? -OR- speakers with 8 Ohms impedance, power capacity at 100W nominal / 200W max, FR of 50Hz to 20kHz?

Thanks from a guy 60 miles to your North.

EDIT: If I gather correctly from JDEaston's reply, the 100W nominal capacity speakers would be under-powered by this receiver, yes? That's a bad thing, or a non issue?
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post #5 of 15 Old 03-13-2013, 04:25 PM
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Non-issue as Denon AVRs are designed to power 6-16 ohm speakers.

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post #6 of 15 Old 03-13-2013, 04:33 PM - Thread Starter
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Quote:
Originally Posted by jdsmoothie View Post

Non-issue as Denon AVRs are designed to power 6-16 ohm speakers.

And no issue with the power going to the speaker if it's a 100W nominal capacity speaker, other than it just being "under powered?" If it is under powered, how detrimental to the listening experience could it possibly be?
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post #7 of 15 Old 03-13-2013, 04:41 PM
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I'm pretty confident your speakers can be capably driven by an amp/receiver from between 20 and 100W. I've got two Denon receivers (AVR 591 and AVR 1613) with the same power ratings. One is driving a 5 speaker set of Jamo 6 ohm speakers the other driving a 5 speaker set of Energy 8 ohm RC speakers.

Neither one has any trouble driving these speakers to louder volumes than I can stand.

Just because your speakers can be driven up by to 200W doesnt mean you need a receiver that powerful.

My RC-10's can handle up to 175W, RC LCR 200W and RC-70's 250W and they're being powered by a 75 watt receiver.

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post #8 of 15 Old 03-13-2013, 04:43 PM
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Quote:
Originally Posted by jspeciner View Post

And no issue with the power going to the speaker if it's a 100W nominal capacity speaker, other than it just being "under powered?" If it is under powered, how detrimental to the listening experience could it possibly be?

Hardly "underpowered" as those speakers will on average only be drawing < 5W/CH at any given time. smile.gif

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post #9 of 15 Old 03-13-2013, 08:31 PM - Thread Starter
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Perfect. See, this is the stuff I need to learn and understand. I appreciate it.
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post #10 of 15 Old 03-13-2013, 09:16 PM
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Quote:
Originally Posted by jspeciner View Post

Perfect. See, this is the stuff I need to learn and understand. I appreciate it.
Thanks for this question, If I may ask a follow up. What if the speakers are 4ohm? My Denon powers my 4ohm lcr beautifully and it's Dynamic power reads 210 w x 2 ch (4 ohm) What exactly does that mean?
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post #11 of 15 Old 03-13-2013, 09:25 PM - Thread Starter
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I had an older Denon (still have it in storage actually) that I tried to run a pair of 4 Ohms speakers from and it was a no go. Things would work just fine, but after an hour or so the circuit protection would trip and the receiver would shut down. If I remember correctly, it basically has to do with the idea that lower impedance speakers draw (or use) too much power for the receiver to handle. Like jdsmoothie said, Denons are designed to power 6-16 Ohms speakers, and I can confirm that both of mine state that in the manual. YMMV.

I'm sure someone else could explain this more correctly, or correctly, period... I'm just going from vague understanding and memory here.
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post #12 of 15 Old 03-13-2013, 10:25 PM
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Quote:
Originally Posted by wpbpete View Post

Thanks for this question, If I may ask a follow up. What if the speakers are 4ohm? My Denon powers my 4ohm lcr beautifully and it's Dynamic power reads 210 w x 2 ch (4 ohm) What exactly does that mean?

Although "designed" for 6-16 ohm speakers, Denon AVRs can generally also power 4-ohm speakers at average volume levels (ie. -30db to -20db) without issue as well while raising the volume much higher than -20db will likely cause it to go into protection mode. Best served setting the Volume Limit setting to -20db so the volume cannot be raised above -20db.

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post #13 of 15 Old 03-14-2013, 09:26 AM
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Quote:
Originally Posted by wpbpete View Post

Thanks for this question, If I may ask a follow up. What if the speakers are 4ohm? My Denon powers my 4ohm lcr beautifully and it's Dynamic power reads 210 w x 2 ch (4 ohm) What exactly does that mean?
AFAIK, "Dynamic Power" is a marketing term that has no established meaning. Probably, though, it's the very short term "burst" power available to handle transients that may last 1/20 of a second. The alternative is it might be "peak" power, which is another marketing term/misnomer/undefined term often used to define the instantaneous power at the very top of a sine wave. While it's true that tha amp makes that much power at that point, it's equally true that it makes zero power for an exactly equal time at the crossoing point from positive to negative, so it's about as useful as saying the power is zero. (Except you can usually assume peak is around twice the RMS).
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post #14 of 15 Old 03-16-2013, 01:38 PM
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I've been very surprised with it's perfomance so far. I thought I'd have to upgrade but now, not at all. Now. my understanding of ohm to wattage is that a good amp will double the wattage output from 8ohm to 4ohm, is that correct? Also, other than increasing the volume, what does increasing the gain produce, more wattage to the speaker? I have my lcr's set to +5 so that I can keep the volme down around -30 for movies and so far so good.
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post #15 of 15 Old 03-16-2013, 01:45 PM
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yea, i get that. I had a sub that was rated at 800watts peak and blew the amp twice. Now I have a better one rated at only 350watts and I don't think I've even woken it up yet smile.gif
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