Oon,
1 watt could be enough for you, but it would not be enough to produce classical music at live front row levels, though would be adequate for solo acoustic guitar- I just checked mine at about 90-96 dBC fast at one meter.
First, lets address the noise level for safety:
dBA Slow
NIOSH (1998)
85 for 8 hours
90 for 2.5 hours
95 for 47 minutes
100 for 15 minutes
dBA Slow
OSHA (1998)
90 for 8 hours
92 for 6 hours
95 for 4 hours
97 for 3 hours
100 for 2 hours
102 for 1.5 hours
105 for 1 hour
110 for 1/2 hour
115 for 1/4 hour
Note that these are "A" weighting scale, which rolls off 50 Hz by 30 dB relative to 1000 Hz, one could add 30 dB to the above limits at 50 Hz and not be above a safe level.
Also note that the the readings are "slow" which averages out peaks, so peak level can be well above those levels.
Also, these levels are set for industrial type noise, music (of the non-industrial kind ) is not nearly as hard on the ears. As an example, an exposure to my table saw for as little as one second will make my ears ring for some time, while exposure to music of the same dBA level won't cause any ringing.
Although your driver may be 94 dB midband, it probably is 10 dB (or more) less around 50 Hz, lets say 84 dB. Add a bass guitar (low E is 40 Hz, low B, 31 Hz) to the solo acoustic guitar, and it now needs 10 watts to keep up with the realistic acoustic guitar 1 watt level. If you include the equal loudness compensation needed to hear 50 Hz at an equal level as 1K, add another 10 dB to the 10 watts, now we need 100 watts, assuming no power compression.
Step that up to the peak demands for classical music, easily more than 10 dB more for some genres, and we need 100-1000 watts peak or so for the kettle drums and such.
As a point of reference, my boat sound system has six Seas 6.5" speakers (4 coax, 2 helper woofers) and a 10 watt amp. The system is flat to below 40 Hz. With most music, the system gets louder than I would want to listen to, but with some bass-heavy genres, the amp clips with the mid range only producing in the 85 dBA range.
Tube amps with output transformer clipping is generally less objectionable than direct coupled transistor amps, but I know for me to be happy with a one watt amp would require a LF output (in the 30Hz range) of in excess of 100 dB one watt one meter.
The size of that speaker would not make me happy, so I still want 10-200 watts of power, even though the average in the midband can be satisfied with a tiny fraction of that power for most of my listening.
Art Welter
"Bob Carver visited a famous sound researcher who was attempting to recreate the "snip" of an ordinary pair of scissors. He used no less that TWENTY-FOUR 200-watt amplifiers for playback. Yet when viewed on an oscilloscope it was apparent that the top of that instantaneous transition was being distorted. Believe it or not, he needed more power!"
2 watts ... yep should work ..........
2 watts ... yep should work ..........
a.wayne, I don't get your point. Are you talking about inefficient speakers, a big space, or both?
I've done the measurements, I've done the math, I've tested it on my system and others.
FWIW, I'm not trying to produce 100dB average with 15dB headroom in a big space. I've done that enough as a pro. That takes gobs of power, for sure.
But for the average Joe in his living room at average listening levels? He just doesn't need that much power. If you can hit 85dB average at the listening chair with ~16dB of headroom, that all most folks want at home. Higher levels are rarely comfortable. You just need to figure out how much power that takes with your speakers and your room. 10 watts peak is plenty for me. And I listen loud enough that I can't hear my wife when she comes in to talk to me.
I do agree that 2W is not enough for most systems, it would limit even my Voice of the Theater system. But 5-10W (clean) will give me very high peak levels. That's 6-9V. For drunken parties I break out the big 30W tube amp. It all depends on what you want to do.
I've done the measurements, I've done the math, I've tested it on my system and others.
FWIW, I'm not trying to produce 100dB average with 15dB headroom in a big space. I've done that enough as a pro. That takes gobs of power, for sure.
But for the average Joe in his living room at average listening levels? He just doesn't need that much power. If you can hit 85dB average at the listening chair with ~16dB of headroom, that all most folks want at home. Higher levels are rarely comfortable. You just need to figure out how much power that takes with your speakers and your room. 10 watts peak is plenty for me. And I listen loud enough that I can't hear my wife when she comes in to talk to me.
I do agree that 2W is not enough for most systems, it would limit even my Voice of the Theater system. But 5-10W (clean) will give me very high peak levels. That's 6-9V. For drunken parties I break out the big 30W tube amp. It all depends on what you want to do.
Agree 100%. It also depends on what your defiition of "reasonable SPL" is. I think you and I (and many others) agree on what this is.
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Pano,
It's all academic as you have stated i was just referencing Mr Carver's perspective..
I do believe you need a lot more than 10 watts even with such high sensitivity speakers. Music type makes a difference and that difference is how the sound is reproduced. Myself favoring a scope for such endeavors not a dvm.
Try reproducing sarafina or any of hugh masakela recordings (before db wars) and see what i mean. Guns of navaronne by the skatellites ( live version) or burning spear live at montreaux , phantom of the opera et al and you will see the power requirements necessary to sound "correct" will far exceed this 10 watt you speak of .
i would suggest no less than 50 watts rms for speakers with high sensitivity, most with avg sensitivity will require 200 watts RMS and again speaker Impedance magnitude and phase play a role here.... You may need more..
But of course your typical dynamically dead stone music is another story, since most of you are intoxicated while listening 2 watts may work ...
It's all academic as you have stated
i was just referencing Mr Carver's perspective..I do believe you need a lot more than 10 watts even with such high sensitivity speakers. Music type makes a difference and that difference is how the sound is reproduced. Myself favoring a scope for such endeavors not a dvm.
Try reproducing sarafina or any of hugh masakela recordings (before db wars) and see what i mean. Guns of navaronne by the skatellites ( live version) or burning spear live at montreaux , phantom of the opera et al and you will see the power requirements necessary to sound "correct" will far exceed this 10 watt you speak of .
i would suggest no less than 50 watts rms for speakers with high sensitivity, most with avg sensitivity will require 200 watts RMS and again speaker Impedance magnitude and phase play a role here.... You may need more..
But of course your typical dynamically dead stone music is another story,
since most of you are intoxicated while listening 2 watts may work ...Pano,
It's all academic as you have stated
as a purveyor of amazingly high powered amps, is that at all surprising?
I think you're still overlooking the incredible range of room sizes and acoustic properties found in the type of domestic listening situations in which the "Full-Range" subcategory of loudspeakers would generally be used.
emoticons notwithstanding, I find the above sentence insulting, and certainly ignorant of the range of music to which "most of us" might listen - hell, even chix and acoustic guitars can be highly dynamicBut of course your typical dynamically dead stone music is another story,
Sure, I love my o'scope, too. But I doubt that Oon, the OP owns one - nor do must folks. Thus the method I posted in this thread. As long as playback is digital, it's easy to figure out your peak level. It's set by the medium itself.
Of the many recordings I own and have looked at, most Jazz, Pop and Rock is masted at an average level of -16dB to -18dB (from full scale.) Some big band and a lot of classical is mastered at -20 to -22dB. OK. So if I set my average loud level with an SPL meter or by ear, then measure a 120Hz tone that is mastered at the same level as the music, then it's easy to figure out what the peak will be.
Since -16dB is typical, that's what I supplied as a reference level. -18dB is another typical mastering level.
From there is just a matter of math and Ohm's low to figure out your peak levels. The power needed will depend on 4 factors:
- Speaker sensitivity.
- Room size and acoustics
- Level you find "loud enough"
- Mastering levels of your music
Items 1&2 can be measured with a DVM and test tone and then related to item 4.
Since we don't actually know the mastering levels of Oon's music, the -16dB point was chosen as typical. Add another 2dB if you have more dynamic stuff. Simple. It all comes back to gain structure - again.
Gain structure ..... there's that word again......
Actually good suggestion Pano, unfortunately most amps will not have an linear output due to the speakers magnitude and phase, we need a lot more than we think ...
Listening levels ..
Typically , similar to yours, 86-88 db din this does vary of course, very music dependant. Pano if you ever have the chance grab your scope and give it a test, i would be interested in hearing the results considering your current speaker's high sensitivity.
regards,
Actually good suggestion Pano, unfortunately most amps will not have an linear output due to the speakers magnitude and phase, we need a lot more than we think ...
Listening levels ..
Typically , similar to yours, 86-88 db din this does vary of course, very music dependant. Pano if you ever have the chance grab your scope and give it a test, i would be interested in hearing the results considering your current speaker's high sensitivity.
regards,
Amplifiers amplify voltage with a linear output compared to the input until the amp clips, or current limits.Gain structure ..... there's that word again......
Actually good suggestion Pano, unfortunately most amps will not have an linear output due to the speakers magnitude and phase, we need a lot more than we think ...
Loudspeakers have differing impedance with differing frequency, but will respond linearly to the delivered amp voltage, as long as the voice coil has not heated to the point where the impedance rises, (thermal compression), and the speaker has not exceeded Xmax.
With dynamic music as Pano listens to (16 dB or more crest factor) thermal compression is not an issue.
I just put a Nora Jones CD in my Alesis Masterlink ( a CD mastering unit), the VU meters seldom went below -9 dbfs...
With the volume wars raging, many CDs now have similar dynamic range to pink noise, which is only 12 dB.
Hi,
Not meaning to insult anyone, but I suspect some posters don't own high efficiency speakers, so don't really know what this topic about. Nelson pass has an alternate website called 'first watt', where he is looking at low power amplifiers. There is an article there on why he high efficiency speakers are mated with valve amps. The minimum of my 20 W valve amp is about 7am position. I normally listen at the 8 am position...
Most speakers 2 way crossover in a box, have efficiency of about 85dB or so. small fullrangers including a bit more normally built fullrangers, Jordan, markaudio also have about that efficiency. Then there are the high efficiency 8inch papercones, Fostex, Lowter and this SEAS speaker which have 95dB efficency. This is done by a different optimisation of the motor system. So a 1W on this speakers will sound more like 10 watts on a normal speaker.
I have a few scopes at work, but none at home. Maybe I should look into buying one of them hand held portable ones...
Oon
Not meaning to insult anyone, but I suspect some posters don't own high efficiency speakers, so don't really know what this topic about. Nelson pass has an alternate website called 'first watt', where he is looking at low power amplifiers. There is an article there on why he high efficiency speakers are mated with valve amps. The minimum of my 20 W valve amp is about 7am position. I normally listen at the 8 am position...
Most speakers 2 way crossover in a box, have efficiency of about 85dB or so. small fullrangers including a bit more normally built fullrangers, Jordan, markaudio also have about that efficiency. Then there are the high efficiency 8inch papercones, Fostex, Lowter and this SEAS speaker which have 95dB efficency. This is done by a different optimisation of the motor system. So a 1W on this speakers will sound more like 10 watts on a normal speaker.
I have a few scopes at work, but none at home. Maybe I should look into buying one of them hand held portable ones...
Oon
Good question. I use a volt meter set to the 20V AC range. But I don't measure music or noise, I measure a 120Hz sine wave. Why? Because I know that the meter is accurate at 120Hz with a sine.
To get that 120Hz sine at the same level as the average music level of the tracks I've been listening to, I simply generate it at that level (-16dB, for example) in software. So I'm using software to measure the RMS value of the music, then making a 120Hz sine that is the same level. I then measure that sine wave with my DVM at the same volume setting of the amp. I don't trust the DVM on music or noise.
To get that 120Hz sine at the same level as the average music level of the tracks I've been listening to, I simply generate it at that level (-16dB, for example) in software. So I'm using software to measure the RMS value of the music, then making a 120Hz sine that is the same level. I then measure that sine wave with my DVM at the same volume setting of the amp. I don't trust the DVM on music or noise.
Hello ,
You do realize that not all amplifiers can maintin there voltage output when impedance drops or into phase angles of -60 deg for eg. I do agree on the db wars with CD's , pano is aware of what i ask and the type of music expected for the eval..
regards,
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