[Guy 13]

Hi all Audio Circle members.

It is often said that low wattage amplifier (2wpc) have very limited headroom even with high sensivity (95db) speakers.

I will take the example of my Decware SE84C+ (2wpc) amplifier with my GR Research V2 (95db) speakers.

My normal listening level is 85db, therefore,
with my 95db speaker at 85db level, I would only need 1/8 of one watt.

Am my correct?

That means if the amplifier is only operating at 1/8 watt it as sixteen (16) times (Fold) the power in reserve.

Does that make sense to you?

What is the ideal reserve of watts to take care of the burst of power hungry spikes of music?

I think I saw somewhere on the Internet, that the ideal reserve of power should be 50 times what is required for your normal listening.

If I listen to music at 85db with 95db speakers,
I would then require a 4wpc amplifier.

Please comment and educate the ignorant or the below average knowledgeable audiophile.

Guy 13
AKA: The GUY that wants to learn.
 

 

[Ericus Rex]

Check out the Music Reference circle here on AC.  Roger has talked about this many times.  He says you only need 10X the average power for peaks.  This is certainly a contentious issue and there are many differing opinions but I think Roger really knows what he's talking about and you should be OK with what you have (16X).

[srb]

First, to calculate the power required for your 95dB speakers for an 85dB normal listening level, your calculations may (or may not) have to be adjusted as the 95dB spec is based on (a) 1m listening distance, (b) one speaker and (c) no wall boundary reinforcement.
 
(a)  Each doubling of 1m listening distance will decrease output ~ -6dB
(b)  2 speakers will have ~ +3dB greater output than a single speaker
(c)  Wall boundary reinforcement could be from ~ +3dB when placed next to walls to ~ +6dB when placed in corners, depending on distance.
 
In the end, if it still calculates to 1/8W for 85dB output for your particular listening distance and speaker placement, 16 times the power (2W) would give you the capability of 12dB peaks.  Depending on the music you're listening to, it may have as little as 6dB peaks for highly compressed music and could have possibly as much as 25dB peaks for uncompressed high dynamic range music.
 
A 4W amp would allow another 3dB, or 15dB total peak.  A 12.5W amp would allow 20dB peaks and a 40W amp would allow 25dB peaks.
 
Steve

[Guy 13]

First, to calculate the power required for your 95dB speakers for an 85dB normal listening level, your calculations may (or may not) have to be adjusted as the 95dB spec is based on (a) 1m listening distance, (b) one speaker and (c) no wall boundary reinforcement.
 
(a)  Each doubling of 1m listening distance will decrease output ~ -6dB
(b)  2 speakers will have ~ +3dB greater output than a single speaker
(c)  Wall boundary reinforcement could be from ~ +3dB when placed next to walls to ~ +6dB when placed in corners, depending on distance.
 
In the end, if it still calculates to 1/8W for 85dB output for your particular listening distance and speaker placement, 16 times the power (2W) would give you the capability of 12dB peaks.  Depending on the music you're listening to, it may have as little as 6dB peaks for highly compressed music and could have possibly as much as 25dB peaks for uncompressed high dynamic range music.
 
A 4W amp would allow another 3dB, or 15dB total peak.  A 12.5W amp would allow 20dB peaks and a 40W amp would allow 25dB peaks.
 
Steve

Hi Steve and all Audio Circle members.

Thanks a lot, that's super good information,
I was not expecting so much useful information,
but since it's there,

I will take it with pleasure.

With your information,
I will do some calculations with the dimensions if my room,
placement of the speakers in relation to the walls
and listening distance from my speakers
and see what I will come up with.

I will get back to you with some results.

Thanks again.

Guy 13

P.S.
Audio Circle is the top of the top when it comes
to get good information.

[doorman]

Also keep in mind that a xover will soak up power. One reason why single driver speakers
can get along with low powered amps.
Don

[ebag4]

Don't forget that your V1s and V2s are powering everything under 200Hz with a separate amp.  With just the coaxial being powered from 200 Hz and up, your 2 watt amp will play even larger.

Best,
Ed