David Head
Second Unit
- Joined
- Jul 5, 1999
- Messages
- 302
There has been a lot of discussion about some of the test numbers published by Sound & Vision magazine for recently reviewed receivers. The number that is questioned the most is usually the number of watts with all channels driven. There is a good article by David Ranada in this month's Sound & Vision that explains the numbers behind the receiver tests. The article mentions that it is more important to pay attention to the dBW figures to determine how loud a receiver can play. Here are a couple of comments from the article:
"Stating power capabilities in dBW is useful in another way; you can simply add dBW power figures to a speaker's sensitivity rating to get an approximate value for the maximum undistorted sound level that can be generated by a given receiver (or amplifier) with that speaker...
You can actually trade off receiver power for speaker sensitivity...A very careful shopper can save money by buying a less powerful receiver and still end up with a system that can play very loud if the speaker sensitivities are high."
Let's take a look at the Onkyo 696 numbers that have been questioned. The number listed for 5 channels driven at 8 ohms was 46 watts and a dBW of 16.5. My speakers (PSB Image) have a sensitivity rating of 91 to 92 dB. That means that in my system I can get up to a 108.5 (16.5 + 92) dB SPL at 1 meter per speaker with all channels driven. I happen to sit more than 1 meter away (closer to 2.5 meters), but it will still play louder than I will ever listen to it...
David
"Stating power capabilities in dBW is useful in another way; you can simply add dBW power figures to a speaker's sensitivity rating to get an approximate value for the maximum undistorted sound level that can be generated by a given receiver (or amplifier) with that speaker...
You can actually trade off receiver power for speaker sensitivity...A very careful shopper can save money by buying a less powerful receiver and still end up with a system that can play very loud if the speaker sensitivities are high."
Let's take a look at the Onkyo 696 numbers that have been questioned. The number listed for 5 channels driven at 8 ohms was 46 watts and a dBW of 16.5. My speakers (PSB Image) have a sensitivity rating of 91 to 92 dB. That means that in my system I can get up to a 108.5 (16.5 + 92) dB SPL at 1 meter per speaker with all channels driven. I happen to sit more than 1 meter away (closer to 2.5 meters), but it will still play louder than I will ever listen to it...
David