watts,db,spl???

littlewoodboats

How does all of this work?

I am asking as I just got back into stereo and in all honesty I did not know much about it to begin with.

I recently picked up a pair of SDA 2A rated at 92db 1watt one meter

How does the db/spl change with amplifier power?

reeltrouble1

for every 3db increase you need twice the wattage.

RT1

zingo

Get a pair of Klipsch speakers and FEEL the SPLs...

zingo

Sound Pressure Level and Power

Sound Pressure Level

``Threshold of audibility'' or the minimum pressure fluctuation detected by the ear is less than of atmospheric pressure or about N/m at 1000 Hz.
``Threshold of pain'' corresponds to a pressure times greater, but still less than 1/1000 of atmospheric pressure.
Because of the wide range, sound pressure measurements are made on a logarithmic scale (decibel scale).
Sound Pressure Level (SPL) , where N/m.
SPL is proportional to the average squared amplitude.
Sound Power

Total sound power emitted by a source in all directions.
Measured in watts (joules / second).
Sound Power Level (PWL) = , where watts.
Sound Intensity

Rate of energy flow across a unit area.
Sound Intensity Level (IL) = , where watts/meter.
Multiple Sources

Two equal sources produce a 3 dB increase in sound power level.
Two equal sources produce a 3 dB increase in sound pressure level, assuming no interference.
Two 80 dB sources add to produce an 83 dB SPL.

pearsall001

littlewoodboats wrote: »

How does all of this work?

I am asking as I just got back into stereo and in all honesty I did not know much about it to begin with.

I recently picked up a pair of SDA 2A rated at 92db 1watt one meter

How does the db/spl change with amplifier power?

Here's a great site that will help you understand SPL requirements & a host of other information all audio & video related.
http://myhometheater.homestead.com/splcalculator.html

Joe08867

The SPL you are speaking about with those specs is sensitivity more than output. I have had my SDA2's well past 100db before.

The sensitivity is how much sound they can output at 1 watt from 1 meter away.

For smaller amps and flea watt tube amps the higher this sensitivity the better (Usually) that is why Klipsch has such a strong tube following. There speakers are very effecient. This doesn't always translate into better sound though. I have seen very inefficient speakers that sound just awesome but need more power to get that awesomeness out of them. Polk Lsi9's come to mind.

steveinaz

With 92dB rated speakers, at:

2watts...95dB would be output
4watts...98dB
8watts...101dB
16watts...104dB
32watts...107dB...and so on.

Notice how quickly power gets gobbled up at higher outputs.

littlewoodboats

Thanks for the replies and information.

With the listed impedance my stuck in Class A Yamaha should be making 19 watts. Sounds great but one can definitely hear it start to run out of gas. I have a stereo tube amp in the works but that is still in the bottom half of the recommended power listings on the speakers.

Based on what has been posted here I should have no issues with a lack of power. I am a bit more responsible with the volume control than in my younger days but it is nice to be able to turn it up a bit should the urge hit me.

steveinaz

92dB is pretty efficient, I think you'll be fine.

tonyb

Don't put so much emphasis on watts, it's current speakers love. Also, with all the numbers thrown out at you, keep in mind those are for 1 meter away. Your room size will have alot to do with it too along with placement. A tube amp should do well on SDA's, but also consider rolling a few to get the sound you like.

cnh

Tony is right. I have all of 50 watts a side (tubes) on my SDA 2Bs and I can't turn the amp past 12:00. Too loud.

Of course the darn thing weighs about 50 lbs. And most of that is transformers, etc.

cnh