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General speaker questions for audio and home theater.

RE: Shouldn't 50 watts be enough for any speaker?

The factors involved focus on room size, volume level desired, and the quality of the SET amplifier, and the maximum power (in watts) the speaker is capable of handling, and the maximum SPL the speaker can handle, the speaker's impedance. When the speaker drops from 8 ohm to 4 ohms it demands double the power from the amplifier.

If your speaker is playing 300hz at 8 ohm and your amp is using 40 watts and a bass line comes in at 50hz and the speaker drops to 4 ohm then the amplifier will be asked for 80 watts to meet the requirement. A SET amp of 50 watts will now run into distortion and the bass line will be flabby. SS or tube the amp will send distortion to the speakers and tweeters do not like being sent 50 watts of distortion - boom there goes tweeter.

I'll use my Wharfedale E-70 (Vanguard edition) as an example. The speaker is 95dB sensitive and sits at mostly at 10ohms and has a max SPL of 119dB which is stupidly loud. It can handle 175watts continuously. So what would your 50-watt amp do?

Note that 90dB is ear damaging loud! Download an SPL measuring program to your phone - sit in your chair hold up a smartphone and measure the level of listening and I suspect a lot of people might be surprised that 80dB is pretty darn loud. So regardless of your amp, you are mostly listening to fractions of a watt.

My Vanguards or my other 95dB sensitive speakers this is the result at 1 meter.

95dB @ 1w (let's assume that most good recordings have 25dB of headroom(most rock and pop are far less than this). If you are listening to your music at a baseline of 70dB - the quiet parts of a classical recording with a 1-watt amplifier in a normal-sized room - say 18 by 14 by 9 ceilings then these speakers will be pretty damn loud.

98dB - 2w
101dB - 4w
104dB - 8w
107dB - 16w
110dB - 32w
113dB - 64w
116db - 128w
119dB - 256w
122dB - 512w
125dB - 1024w

So with my Wharfedales and with a 50-watt amp, I am not getting their max volume capability - I would get 111dB.

It comes down to the fact that a 50-watt amp of good quality will drive "anything" but will it drive it at maximum levels full bandwidth in a big room where you sit. More watts will mathematically do that. Regardless of the amplifier design.

I have an 8-watt SET amp so on the speaker above I can get 104dB. With my 50 watt Class A/B Solid State amplifier I can get 111db and with my 70-watt class A/B SS amplifier I can get 113dB and with my 250 watt Class D amplifiers I can get 119dB.

But all of this is kind of moot if 99% of the time I would be listening at 100dB peaks. Then it comes down to the sound quality and if the 8-watt amp sounds the best then who cares about the numbers?

My side suggestion is to buy separates. Get yourself a nice preamp and then you can buy different power amps based on sound quality or for sheer brute strength. I looked at your profile and you list a lot of speakers - so you, like me, may find that on some speakers you will like a 50-watt SET but on other speakers, you may prefer a 500-watt amp.




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