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dumbo
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How Many Watts Are Enough

In the world of big power, big money amps what is your take on how many watts is enough for serious listening in a average size room. My listening room is roughly 9'D X 15'W with a 9' ceiling. My current amp of choice is a Classe CA201 feeding 400w @ 4ohms to a pair of Legacy Signature III towers. I have been thinking about upgrading my amplifier to a higher quality unit but am torn between going with either a low power unit like the PASS XA30.5 or a higher power unit like the Bel Canto REF1000 MkII. I love turning up the volume as much as the next guy but in a listening room the size of mine is there much benefit from having an almost seamless reserve of power on tap from a quality unit like the Bel Canto unit verses a superbly accurate lower power unit like the PASS?

Please discuss your thoughts..Thanks

Jan Vigne
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Re: How Many Watts Are Enough

I think you might want to ask the speaker manufacturer as there doesn't appear to be any information on the sensitivity or reactance of the load for your speakers.

Overall, most listening at "average" levels is done with only a few watts, easily below 20 watts for most material in an average sized room. Even a headbanger can get by with a handful of good watts if the speakers aren't punishing the amp and their sensitivity is high. Judging from their other products I would guess your Legacy's are fairly high in sensitivity but not all that kind to the amplifier as far as reactance goes. That would place an emphasis on quality of power when choosing an amplifier.

There is a certain brute force quality that comes from having massive amounts of wattage on tap. However, I think most people here would tend toward the better sounding amp, not necessarily the more "accurate" amp but certainly the more transparent amp. That would be the Pass in this case.

ncdrawl
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Re: How Many Watts Are Enough
ncdrawl
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Re: How Many Watts Are Enough

and it aint about quantity..but quality.

unless you are DUP.

here is a cool app

http://web.archive.org/web/2008042408581...arger/slide.zip

dumbo
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Re: How Many Watts Are Enough

Thanks to both folks who replied as I appreciate your input. The sensitivity of my speakers are listed in the manual as 93db at 2.83v @ 1m. Based on my inputs on that cool web page calculator provided it appears my current setup is capable of producing 121.4 db SPL at my listening position which I don't doubt for a moment. I'm not too clear on what the other figure means in terms of the amount of gain from the amplifier which is said to be 26 db.

My initial thoughts on how many watts I realistically use during a listening session coincide with what Jan Vigne said about the typical user. Now if I didn't have any neighbors this would certainly be very different but unfortunately I'm forced to keep the peace on most days.

Even taking into consideration the very under rated power listing on the PASS amp of 30 watts I could still push 110 db in my room which is nothing to sneeze at.

Thanks again and this has certainly been very helpful info

linden518
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Re: How Many Watts Are Enough


Quote:
and it aint about quantity..but quality.

unless you are DUP.


Yup. And far too many audiophiles are caught up with voltage to the point that they fail to consider the current delivery, too. How "little" do you think the Mark Levinson ML2 monoblocks' 25 watts sound, for example?

I don't know about all these audiophiles and writers glorifying 1kw+ amps without rhyme or reason. I don't doubt that they serve their purpose with certain speakers, but with others, one probably doesn't need that much. Kind of like a person who only uses a PC for word processing and e-mails deluding himself that he needs the fastest processing chip out there.

commsysman
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Re: How Many Watts Are Enough

400W is probably more power than you need, unless your speaker efficiency is less than 82 DB/W @ 1 meter.

Keep in mind that lowering speaker efficiency by 3db requires twice as much power for the same sound level.

If the efficiency of one speaker is 6db less than another one, 4 times as much power is required; if there is a 9Db difference, 8 times as much power is required, etc.

Before you go anywhere with this question, you should know what your speaker efficiency is rated at, and what level of performance you are getting from those speakers in the current room with your 400W.

93 db/W @ 1 meter is a very efficient speaker. You could probably get all the sound you want with those speakers with as little as 40 W, but ultimately you will never be certain without an actual trial, because the sound absorbtion of the room is almost impossible to estimate; too many acoustical variables.

preistube
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Re: How Many Watts Are Enough

The Sigs are rated at 2.83v, so at 1w/1m they are likely around 90dBs.
Legacy recommends a minimum of 25 watts, the Pass XA30.5 clips at 195 watts/ch 4 ohms, should be more than enough in your room.
Legacy speakers usually like high current amps like the Pass.

Lin

dumbo
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Re: How Many Watts Are Enough

Thanks again for the additional info. I'm leaning very heaviliy towards the PASS amp at this point. I can't think of any other brands I could purchase new in the same price range that would offer as much SQ for the buck.

dumbo
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Re: How Many Watts Are Enough

I wanted to post a brief follow up to my original question on how many watts are enough. Well, I ended up finding a very nice PASS X250 from Audiogon that fit the bill nicely.

Granted, this amp is no lightweight in terms of wattage output considering that I am running it at 4ohms but I can now see first hand that even at a neighbor disturbing listening level the fancy power needle never swings past the halfway point. From my understanding, this indicates that I am still operating in full Class A mode using less then 50watts of power RMS.

I guess it sure doesn't hurt having more power then you will ever need but at the end of the day I now know for sure that I could easily have lived with a solid 40-50watt unit for my purposes.

As a final note for those who may have an i-Phone, there is a nice little Real Time Analyzer App that I purchased for $12 which uses the internal MIC on the i-phone which you can use to get a rough idea on the SPL levels of your listening room. Granted, it has it's limitations but is still a pretty neat little App to give you a rough idea on your normal music listening levels. I was quite surprised to see how low mine actually was falling in usually around 90-95db during a more spirited listening session.

Elk
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Re: How Many Watts Are Enough

Wonderful amp.

90-95dB is seriously loud.

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