Running on low power.

[92135011]

I have noticed some tube amps run at around 4watts whereas others run at bout 8.
Would something like this run something like a B&W 601 S3 rated at 88dB/watt?
I understand that on the B&W site, it says that the power handling is 25-100 watts. Does this neccessarily mean that I need 25 watts to get them work properly?

[markw]

If you only run them at very low levels and don't expect much sound out of them.

When you see that 88db/watt spec it's saying that one watt of power thru them will produce a loudness level of 88db (dunno what frequencies they used) at 1 meter from the speaker. The farther you get from the speaker, the lower the loudness level will be.

For each doubling of power to the speaker, you realize a loudness gain of 3 db. So, assuming one meter from the speaker, you'll have these levels at these powers:

1 watt = 88 db
2 watts = 91 db
4 watts = 93 db
...game over. You're into clipping now and there's not even anything left over for peaks.

Had you more power to play with, it would extend out as such:

8 watts = 96 db
16 watts = 99 db
32 watts = 102 db
64 watts = 105 db
132 watts = 108 db
264 watts = 111 db
528 watts = 114 db

I'm sure you can transpose these numbers to see how a more efficient speaker would play out. Simply start out at the level specified for one watt and for each doubling of power, simply add three db. The benefit of an efficient speaker can readily be seen.

A speaker with an efficiency rating of 91 db would use half the power of this speaker for an equivalent loudness. Likewise, one with a rating of 94 db would require on quarter the power, etc,,,

Now remember, these levels are for listening at on meter from the speaker. Generally the listening position is much farther away from the speaker than that.

Granted, most listeing uses less than on watt on a continious basis, but that extra power is needed for peaks and bass. If you want to play with flea power, you'll need more efficient speakers unless you like the sound of clipping.

[92135011]

I understand the concept of how the loudness adds on.
However, what really confuses me is the power handling spec of 25-100 watts/metre.
Does that mean below 25watts and you're screwed?
I have also read that with every doubling of distance, 6dB is lost. assuming I'm listening from 3-4 metres away, I would be able to extract about 75-80dB with consideration of the peaks. Using a physics text book, this is considered as between a vacuum cleaner and busy traffic. Seriously, I dont know if that's loud enough or not.

BTW, are there any other loudspeakers out there that have higher sensitivity, but better power handling that have similar sound of B&W? I like B&W's warm vocal midrange.

[markw]

I think what they are trying to say is that less than 25 watts won't do them justice, even at low listening levels. ...but tastes vary. Yours may differ.

Average levels and peak levels are two different animals. For an apparant doubling of loudness, you need about TEN times the power. With that in mind, rethink the math in the above examples, particularly in light of your 6 db distance drop.

As far as the rest, I'll let others add to it. I merely put forth what's considered good, "sound" advice, arrived at from years of experience by others and myself.

YMMV.

[spacedeckman]

You need to look at the characteristics of the speaker and its intended use. Most of your listening is done at less than a watt, with peaks that may hit a couple of watts on really dynamic content, but only for milliseconds. However, with a speaker rated at 86dB (understand that this is probably an optimistic rating at 1kHz), 4 watts isn't going to do very well. If it were 89dB, it would do twice as well, at 92 dB it would do 4 times as well, and at 95dB it would do 8x as well, hence the search for really sensitive speakers if you are a SET kind of guy. It makes all the difference in the world.

What B&W is saying is that they want something with some more headroom, so they are ARBITRARILY setting their low end at 25 watts. That way, you will have decent headroom, essentially what you would have with the 4 watt amplifier into a 94 or 95dB speaker.

Make sense?

[92135011]

What you you guys suggest for an alternative speaker to B&W 601 S3?
Im looking for similar cost and sound, but of course much greater sensitivity.

[bturk667]

I believe you would be making a big mistake trying to use a low powered SET, with a speaker whose sensitivity is 88 db. I think you would need at least 25 watts per channel to get good sound from your B&W's. The reason why is because of their impedance. B&W's are not the most amp friendly in that respect! If you really want to try a SET, you should find a speaker whose snsitivity is at least 94db. Try Coincident Speaker Technologies, klipsch ( I do not like them), other horns or a lowther type speaker, say from Moth Audio!