AV Receiver and Speaker Advice

[Slogan]

Hi guys, just wanting some friendly advice regarding a new audio setup. I recently purchased a Samsung UE55JU6800 and have decided to take the plunge to get something a bit better than the TV's audio.

I'm going in at entry-level 2.0 (not too bothered about Surround Sound) so it won't be anything mind blowing but I just wanted to run it by someone before I pull the trigger and purchase. I was ready to purchase it all yesterday but then I started reading about Power Outputs, ohms, Impedance and my head felt like it had caved in after about 20 minutes. And the doubt crept in.

I had the following in mind:

AV Receiver: Denon AVRX520BT
Speakers: Yamaha NSF51

From what I understand, the speakers are 6 ohms and require 80 Watts (Nominal Input) whilst the AV Receiver's Power Output is rated at 90 W for (6 ohm, 1 kHz, 0.7% 2ch Drive). The Denon product page said it would drive 6 ohm speakers but it didn't say how well.

Two questions really:

- Are these okay to be paired together?
- If I wanted to add a subwoofer at a later date for 2.1, does this have an impact on the impedance?

Any criticism or suggestion for change is welcome!

Thanks

 

[lucid]

Firstly don't worry so much about matching the power requirements of the speaker to the power output of the amp. They aren't related in the way you think. To put it another way, the tyres on a typical 4-door family saloon are H rated for up to 130mph, but that doesn't mean that everyone has to drive at that speed all the time or else the tyres won't work

Speaker power ratings are simply a (very) rough guide as to the maximum power they can handle so you don't try to match a 200W/ch amp with a 10W max speaker. But even that isn't the whole story. Distortion is far more important.

For example, you'd think you might be perfectly safe buying a low wattage T-amp from Ebay that claims to put out about 30W and matching it with those Yamahas. But the T-amp doesn't actually generate anything like its claimed power, so it runs out of steam at around 8W (1/3rd way round the dial) and anything louder includes a heck of a load of distortion. The result is a '30W' amp kills an 80W speaker because distortion (a dirty signal) fries the voice coils way faster than 150W of pure clean signal power.

Second, the power figure for the Denon is optimistic. A 1kHz test tone will produce a flattering power delivery figure. A 20Hz-20kHz tone is a better representation of a musical signal, but it's more likely to yield 40-50W per channel as a power measurement.

Third, you don't need that many watts in any case, so it's largely academic. Those Yams are rated at 89dB efficiency. That's actually pretty good. It means they make good use of the power being delivered from the amp. The efficiency figure is properly displayed as dB/W/m, and that breaks down as one speaker will make a sound 89dB loud when fed with 1 Watt of power and measured from 1 metre in front of the speaker. It's about as loud as being stood next to a tractor revving its engine; loud enough to make conversation difficult. Sound dissipates with distance. Say you sit 4m from a pair of these speakers in your room. You'd only need 7 watts per channel to make the same loudness for where you sit.

The Yamaha speakers are a bit of an unknown. Normally budget floorstanders look great but don't quite deliver the promise compared to stand-mount speakers at a similar price. The reasons are that the boxes cost a lot to produce and so the bracing you get with good floorstanders (>£450) is missing. Other corners cut are the thickness of the cabinet wood (MDF really) and the size of the magnets on the backs of the drivers. The result is that the speakers struggle to produce the tight accurate bass that stand-mounts and better floorstanders do. You might also find that the midrange (the bit of the frequency range responsible for reproducing voices and the main signature sound of instruments) doesn't sound quite as clear and defined as the alternatives.

Yamaha is a big company and it spans a pretty huge range of gear. This also includes speakers. The brand makes some very fine speakers in other areas such as for studio use. It even has a reference speaker or two under its belt (the 1970's NS-1000 for example). However, the rest of the ranges have tended to rest on the laurels of the high-end products, and so outside of Japan they don't get so much attention. That's hardly surprising too given that Europe in general and the UK in particular is home to arguably the finest loudspeaker manufacturers in the world. It's a tough market here. The NSF51's may be that rare thing of a good product that can't get a foothold in a ferociously competitive market so it has been sold off cheap, or it might just be yet another cheap floorstander. The fact that the efficiency is decent does bode reasonably well, but I think you should really take a listen and compare them against Tannoy Mercury V4/V4i (floorstanders) and Wharfedale Diamond 220 (stand-mounters) before throwing down some cash.

As for subs, no, they won't affect impedance at all. Depending on the sub it will either connect via a phono lead (low level input) or speaker wires (high level input) and neither will have any impact on impedance levels for the other speakers.

 

[Slogan]

lucid, first of all thanks for taking the time to make such a detailed reply, it's genuinely appreciated. I have read that much recently it's hard to know what is fact and what is fiction!

I much prefer floorstanders and I understand what you're saying, particularly when it comes to unclear voices in films. Whilst almost any audio setup would probably be a significant improvement for me, I would like to get something decent rather than having it triggering the need to "upgrade" in a few months.

Will certainly check out those recommendations as well.