Marantz NR1403 5.1 Channel Receiver Enough Power for Towers?

[sonicboom]

50 watts per channel (discrete amps).

What does this mean really? And will this receiver be enough to power, say the towers?
My room is approx 12x20x8 and I don't listen at "reference" levels. Though I want it loud sometimes when Mrs is away.

Advice please. Thanks a lot.

[Dark Ranger]

Hi sonicboom,

Marantz rates this receiver at 50 watts per channel, 2 channels driven. This means that the receiver's power supply can deliver up to 50 watts each (into a specific load, e.g. 8 ohms) for two channels driven simultaneously. Assuming the discrete amplifier section is identical for every channel, you can drive any 2 channels to 50 watts each.

OK, that's great for, say, front left and front right stereo listening. What happens when you add additional channels like in a 5.1 or 7.1 setup? Unfortunately, the vast majority of receivers don't provide official specifications on power output for 3, 5, or 7 channels driven simultaneously, even though the receiver is advertised as 50 watts x 5, 90 watts x 7, or 120 watts x 9, etc. The receiver power supply simply cannot deliver 50 or 90 or 120 watts cleanly into all channels driven. What you end up with when driving more than 2 channels is simply less power delivered into each channel. So in the case of the Marantz, perhaps it's something like 20-25 watts per channel, all channels driven (numbers pulled from thin air).

That said, real-world content (like music and movies) is much different than the pure sine waves, test signals, and signal generators used when measuring power handling. Real-world power output can be higher than what's seen on a test bench because real-world content is not usually continuous (e.g. 1 kHz into an 8 ohm load).

50 watts is actually a LOT of power for audio signals. As an example, the Sierra Tower in-room sensitivity is about 92 dB @ 2.83 volts measured at 1 meter (3.281 feet). For reference, 2.83 volts is 1 watt with a 8 ohm load and is 2 watts with a 4 ohm load. This means that the Sierra Tower will play approximately 92 dB when fed 1-2 watts of power (I'm including 2 watts here because the Towers are rated at 4 ohms minimum). For some examples, 90 dB is as loud as a lawnmower, a motorcycle at 25 feet, a hairdryer, or a noisy factory.

So, the Towers can get pretty loud with only 1-2 watts of power at just over 3 feet away. Of course, most folks listen further away than ~3 feet from the speakers, and that introduces other things that I won't get into with this post.

So if one can get by with a few watts, why get an AVR or amplifier with more? One reason is for headroom. Music isn't a constant level. There are transients and peaks throughout the music. The snap of a snare drum, the clash of cymbals, the vigorous bowing on a cello...these are all dynamics that require more "volume" compared to the average volume, and thus require more power to reproduce. The more power you have available, the louder you can play cleanly without clipping. I know folks who routinely push SPL well past 120 dBC average level for weekend parties. Some of these enthusiasts use high-powered amplifiers (200-1,000 watts per channel) to achieve these levels.

My point is that the Marantz receiver will be adequate to power the Towers providing you don't expect rock concert levels. Do you have an SPL meter by any chance? If so, you could get a idea of how loud you listen. "Reference level" is usually around 85 dB average volume, with 20 dB peaks on the main channels (105 dB total) plus another 10 dB for LFE (115 dB total LFE). For me, 85-90 dB average is adequately loud for a 2-3 hour movie or concert. Don't forget that the louder you play, the greater the chances of damaging your hearing. 90-95 dB sustained (constant) is enough to cause damage.

Whew. That ended up longer than I planned.

[sonicboom]

"Whew" indeed, Jacob.

I really appreciate the comprehensive reply you posted. It was an education and at the same time a successful rescue operation. I was almost planning on settling for 50 watts.

How about I just ask you which receiver you would recommend for me? Budget is $800-1000. Set-up is 5.1, room is 12x20x8, listening levels are not "reference", all-Ascend speakers (currently running CMTs for front, CBMs for surround, planning on getting towers when funds allow).

Thanks again very much.
Daniel

[Dark Ranger]

The goal with my previous "essay" was to shed light on how receivers are rated and what can be expected. I was just trying to explain the meaning of the stated power output as requested.

Honestly, there are more similarities than differences with AVRs these days. Even at the price range you mention, most of the AVRs are still rated into 1 or 2 channels driven. The difference between 50 watts and 100 watts is not twice as loud, it's actually 3 dB which is only about 1.23x louder. In my opinion, one should not buy a receiver for the power, but rather for the features included. A receiver is design of compromise. Buy the features you need/want and the included amplification should be fine for reasonable listening volumes.

With the Marantz NR1403 you mentioned, 50 watts is actually more than enough to adequately drive the Towers or any other speaker from Ascend to reasonable volumes. Without a SPL meter, it's hard to know exactly how loud you like to listen. Remember that it only takes a few watts for the loudspeakers to reach reasonable average volumes at typical seating distances. If you want to reproduce an IMAX theater or host block parties, then I definitely recommend a high-powered external amplifier. For regular movies and music, the 50 watt Marantz should be fine. It'll be plenty of power for normal listening volumes.

That said, one issue with most receivers is that they are not officially rated to drive 4 ohm speakers, only 6-8 ohm speakers. Even the top-of-the-line Marantz AVR is rated for 6-8 ohm speakers. Dave does rate the Towers compatible with 4, 6, and 8 ohm amps and receivers, even though the Towers dip down to 4 ohms at certain points. You should be OK if you really want this receiver.

I'll stop there.

[Dark Ranger]

OK, I'm going to mention two other things that may be worth consideration.


1) You are probably aware of this already, but the NR1403 is a 5.1 channel receiver. If you ever want to install a 7.1 system to take advantage of today's cutting-edge Blu-ray audio formats, you'll need a new receiver since the NR1403 doesn't support 7.1. Since you're looking to buy, I suggest getting the next step up (model NR1603). Ultimately, you're the one to make this call, but I do recommend you at least consider it. Over half of my growing Blu-ray collection has 7.1 channel DTS or Dolby soundtracks.

2) If you ever decide you'd like to add an external amplifier for more power, the new Marantz receivers have pre-outs available. For the entry level models (NR1403 and NR1603), I give Marantz huge bonus points for including Front Left/Right pre-outs at this price point. Most receivers exclude pre-outs from entry level models so you're forced to spend more for that feature. The Front Left/Right channels take much of the brunt for reproducing music and movies. An external amplifier for these two channels would free up the AVR power supply for just the center and surrounds, a much easier load.

If you want pre-outs for all channels, you'll have to step up to the SR5007, but I don't think that's necessary for most folks. Perhaps the option to add an external amp down the road (if desired) will ease your mind regarding power.

[sonicboom]

Many thanks again, Jacob.

Your enlightening "essay" certainly clarified a lot of things pertaining to my AVR conundrum. I'm surprised to know that jumping from 50 watts to 100 watts only gives you 1.23x louder. I listen at reasonable levels only, so the NR 1403 seems to be powerful enough for my requirements.

However, the "what if" bug is pestering me, so much so that I'm starting to consider the SR5007 more seriously now. Looks like this receiver is more future-proof than the NR1403.

Thanks a lot. I really appreciate your sound advice (if you'll forgive the pun).

[sonicboom]

Just an update.

I "settled" for the Marantz NR1403 and discovered that it is more than powerful enough to drive my Ascends (340 mains and 170 surrounds) to sound levels I listen at. And way beyond.

Satisfied is a good way to put it. I have not experienced higher level AVRs or separates, so my comments are the proverbial two cents.

[Dark Ranger]

Hi Daniel,

Thanks for the update! I am not surprised to hear the NR1403 delivers your targeted listening levels. Marantz offers some great AVRs when it comes to quality and features. Congrats on the purchase and enjoy!

[rsmt2000]

Hi Daniel,

Thanks for the update! I am not surprised to hear the NR1403 delivers your targeted listening levels. Marantz offers some great AVRs when it comes to quality and features. Congrats on the purchase and enjoy!

I have traded in my old pioneer receiver and a 5.1 set up I am no longer using with a new marantz 1603. I was hesitant to get it as comparatively priced Denons get me more bells and whistles. But the trade-in store only sells marantz and other very highend gear. I just picked it up over the weekend and am running my Sierra towers w/RAAL. so far so good. I had to have the unreliable Airplay and hence the 1603:-). Will update once I hook up my other sources.