Volume vs Watts

Everyone seems to think that they need more watts to get more volume.  While it is true that more watts will be louder than less given the same speaker, it is also true that the speaker is more important than the watts in most cases.

For every 10db gain (double perceived volume) you need a 10x multiplication of wattage.  So a 100watt amp is only twice as loud as a 10watt amp.  The reason this doesn’t normally seem so is that 10watt amps normally have poor spl rated speakers, making the 100watt amp sound more than double the volume.  Playing through a better speaker will help increase your db rating, and hence your overall volume.

So you can see that a 90db speaker on 100watts is less volume than a 102db speaker cab with only 10watts.  Most inexpensive amps come with speakers of about 90-93db.

Now, to keep up with an average drummer you will want about 110db.  To reach this level you could use a 100watt amp with a 90db speaker or you could run a small 10watt amplifier with a 100db or better speaker.

That means my little Dean Markley which is running at 20watts on a 92db speaker is pushing 105db or so.  If I ran it through a rated at 99db that would bring me up to to 112db – plenty of volume for me to do some small gigs with it.  Although more likely I would get a Fender Frontman 65R as it pushes 111db stock on it’s built in speaker, or 120db with a 99db speaker.  This would do small gigs on it’s own and most larger ones simply by plugging in a 4×10 cab.

The calculation for total db is this:
{log (watts of amplifier) x 10} + speaker spl rating in db at 1w = total db output

Or if you want to figure out what db speaker (or cab) you need to hook into to get a certain desired db output:
Desired db output – {log (watts of amplifier) x 10} = Necessary speaker/cab db rating at 1w

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