How much power do I need?

[Jeffo19]

I am running some JM LABS Cobalts(91dB effiecency,8 ohm) in a fairly small to medium size room(12x18). I am wondering if I should go with an RB1050,1070, or 1080. I feel that I really would not need all the extra power from a 1080, or even a 1070, so would the 1050 be a good choice? Will the higher power amps just play louder, and push out more bass from the speakers, or actually sound better??

[mars]

Noticeable increases in sound pressure (say a doubling or 3dB) require logarythmic increases in amp power. You can much more easily damage a speaker with too little power (clipping) than with too much. More current = better woofer cone control (tighter bass). Some's good more's better. Did I leave anything out?

[apodaca]

I have a set of Cobalts and I am currently running a 5.1 set up with an RSX 1056 + RB1070 for the mains (floorstanding). I added an extra 1070 for a future 7.1 but I am not so sure I need it given that all speakers except the fronts are crossed over at 80hz and my multichannel music is only in 5.1 with the universal player bass management at 120hz(fixed).

I also have a spare integrated 1062 rotel amp that can run the mains just fine at reference levels(tried it out for a week). The Rotel amps are very good and have no difficulty going down to 4 ohms. For the bookshelf speakers in the front the Rotel 1050 is fine, if you have large Cobalt mains though I would recommend at least a 1070 if running them at full range for 2 channel extended listening sessions at or above reference levels - just to know you have plenty of headroom and good bass control. Also note the impedance on the Cobalt speakers can dip down to 3 ohms at certain frequencies.

[lvhung]

would buy Rotel RC-06 and Rb 1070 and
prepare to buy some expensives cables

[chrispy35]

I would say the 1050 is fine. Mine never clips and it still has plenty of room even after my ears have decided it's loud enough.

I measured power into my system and it was ~60 W for everything at what I consider far above normal listening levels for me...maybe it was at a nice level for my neighbour though. That 60 W is for everything too: pre, cdp, tuner and amp.

Chris P.

[Ted]

You very well may be okay with the 1050, but the 1070 or 1080 will be even better. In the that size room, the 1050 will probably play plenty loud, but the the higher level amps will give you more headroom and better control, especially in the lower frequencies.

I have a 1080 running my B & W 703's (90dB) in a smaller room than you have and have been very happy with the sound. I had no idea how much bass you could get out of a pair of 6.5 inch woofers with a good source of clean power running them.

Ultimately, you need to see if you can listen to the amps and compare them, at home if you can. Your ears will be the best judge. The better amps will sound better, but how much better and whether it is worth it to you and your pocket book is the big question.

Good luck!!

[Vicente]

I also have a Cobalt set for HT (floorstanding fronts, without subwoofer), and my RSX 1056 moves these loudspeakers without any problem.

If Rotel were not so expensive in Europe I would buy also a RB 1070 for the main channels, just to improve a little bit my stereo listening. I'll do it probably some day.

My advice is that you get the 1070 even though that you will probably have enough power with the 1050, but I'm sure you will never regret those extra watts if you can afford them.

[chrispy35]

If there's no clipping/distortion, how am I having problems with headroom with the 1050?

What am I missing?

Chris P.