7W enough for 90dB speakers?

kacernator · 18th January 2008, 12:46 AM

Is 7W push-pull enough for small room cca 4x3 meters and 90dB efficient speakers?

Thank you.

paulb · 18th January 2008, 12:47 AM

I would say, yes.

zacster · 18th January 2008, 12:59 AM

Probably, unless you want it really loud.

jon_010101 · 18th January 2008, 01:03 AM

If it's a really good, low distortion, 7W amp and the speakers have a reasonably flat impedance curve, you'll be fine. I often drive 85dB speakers with 15W and don't feel it too lacking, but some speakers and amps don't play well together.

Eli Duttman · 18th January 2008, 01:04 AM

Quote:

Originally posted by kacernator
Is 7W push-pull enough for small room cca 4x3 meters and 90dB efficient speakers?

Thank you.

IMO, 7 WPC is not enough. Paul Joppa provides a useful rule of thumb. PJ's rule tells us that an amp/speaker combo should be capable of 102 dB. SPL peaks at a 1M. distance. The rule is for a "typical" space. Adjust accordingly. 4 M./3 M. is not especially small. So, I'd go for the 102 dB. peak. 16 WPC are needed with 90 dB. sensitive speakers.

tubewade · 18th January 2008, 02:25 AM

7 watts is 8.45 dBW; i.e. capable of 8.45 dB more output than 1 watt. With 90 dB/1 watt speakers a single channel should achieve 98.45 dB. With two channels, twice the power, twice the membrane area for an increase of 6dB. Total output = 104.45dB. There will be losses, of course, but this is pretty loud for most types of music. My room is about the same size and I've been quite satisfied with SE 6BQ5s and similarly inefficient speakers, but I don't like Metallica or AC/DC. I listen to Dave Grusin, Chris Botti, Brian Culbertson and Fourplay.

Wade

Geek · 18th January 2008, 02:35 AM

Hi,

No one has asked a very important question.... how big is the room they will be used in?

Cheers!

planet10 · 18th January 2008, 02:46 AM

My room is fairly big (~7m x 11m x 4m). Fonkens are about 90 dB. RH84 ~5W. Most of the time it is fine, but sometimes i'd like more. Working on paying odd a PP 2A3 and helpwe woofers are under development.

dave

planet10 · 18th January 2008, 02:47 AM

Quote:

Originally posted by kacernator
for small room cca 4x3 meters

Quote:

Originally posted by Geek
No one has asked a very important question.... how big is the room they will be used in?

Lets guess 2.5 m ceilings

dave

tinitus · 18th January 2008, 03:00 AM

Noone has asked another important question...what kind of 90db speakers

18th January 2008, 12:46 AM	#1
kacernator diyAudio Member Join Date: Jan 2008	7W enough for 90dB speakers? Is 7W push-pull enough for small room cca 4x3 meters and 90dB efficient speakers? Thank you.

18th January 2008, 02:46 AM	#8
planet10 frugal-phile(tm) diyAudio Moderator Join Date: Oct 2001 Location: Victoria, BC, NA, Sol III Blog Entries: 4	My room is fairly big (~7m x 11m x 4m). Fonkens are about 90 dB. RH84 ~5W. Most of the time it is fine, but sometimes i'd like more. Working on paying odd a PP 2A3 and helpwe woofers are under development. dave __________________ community sites t-linespeakers.org, frugal-horn.com ........ commercial site planet10-HiFi p10-hifi forum here at diyA

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18th January 2008, 12:47 AM	#2
paulb diyAudio Member Join Date: Jun 2001 Location: Calgary	I would say, yes.

18th January 2008, 12:59 AM	#3
zacster diyAudio Member Join Date: Dec 2003 Location: NYC	Probably, unless you want it really loud.

18th January 2008, 01:03 AM	#4
jon_010101 diyAudio Member Join Date: Nov 2005	If it's a really good, low distortion, 7W amp and the speakers have a reasonably flat impedance curve, you'll be fine. I often drive 85dB speakers with 15W and don't feel it too lacking, but some speakers and amps don't play well together.

18th January 2008, 02:25 AM	#6
tubewade diyAudio Member Join Date: Jun 2007	7 watts is 8.45 dBW; i.e. capable of 8.45 dB more output than 1 watt. With 90 dB/1 watt speakers a single channel should achieve 98.45 dB. With two channels, twice the power, twice the membrane area for an increase of 6dB. Total output = 104.45dB. There will be losses, of course, but this is pretty loud for most types of music. My room is about the same size and I've been quite satisfied with SE 6BQ5s and similarly inefficient speakers, but I don't like Metallica or AC/DC. I listen to Dave Grusin, Chris Botti, Brian Culbertson and Fourplay. Wade

18th January 2008, 02:35 AM	#7
Geek diyAudio Member Join Date: Sep 2004	Hi, No one has asked a very important question.... how big is the room they will be used in? Cheers!

18th January 2008, 03:00 AM	#10
tinitus diyAudio Moderator Join Date: Nov 2005	Noone has asked another important question...what kind of 90db speakers

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