help with working out how much wattage i need!

[prowla]

1 hour ago, Downunderwonder said:

2kW in reality heats my lounge. That's reality.

 

Nobody needs a real 2kW. My real 250W amp with 4 ohm of cabs keeps up with enthusiastic drummers no problem.

As per notes a 2kW amp is just under twice as loud as a 250W one (all other things being equal).

[Stub Mandrel]

What's interesting is the frequency/loudness curve that has perceived volume dropping off rapidly below guitar frequencies.

 

Which is why we need more powerful amps than guitarists.

[prowla]

5 hours ago, Stub Mandrel said:

What's interesting is the frequency/loudness curve that has perceived volume dropping off rapidly below guitar frequencies.

 

Which is why we need more powerful amps than guitarists.

I've sometimes wondered about nicking one out of some of the cars that go past. 🙂

[FugaziBomb]

I gig with 1000 watts coming from a Crown XLi2500 into two 18" subs for my lows and another 50 watts of tube power feeding a 2x10.  Is that enough?

[Bill Fitzmaurice]

5 hours ago, Stub Mandrel said:

What's interesting is the frequency/loudness curve that has perceived volume dropping off rapidly below guitar frequencies.

 

Which is why we need more powerful amps than guitarists.

That's one factor, but not the only one. Juts as significant is power density, which increases by 3dB (doubles) with each octave reduction in frequency. While our E is one octave below a guitar E most of our content is two octaves below the guitar, for 6dB, or a quadrupling of power. The real question isn't now much power does the bass need, it's how little does the guitar need. If you've ever stood in front of a Vox AC 30 you know it's not 100 watts.

[Dan Dare]

20 hours ago, agedhorse said:

Understood, though the assumption that Behringer and TC are using similar power modules (actually, the power amp and power supply are an integral part of the main board) isn't accurate. The power supplies/power amps are very different, though they both share a similar ambiguity (creativity) with regards to the way they rate their output power.

 

I don't assume they use the same modules. I was having a dig about claimed output powers and mentioned them because they seem to be notable culprits. I appreciate that not all boards have integral power supplies. I've been toying with the idea of assembling (can't really call it building when all you do is put modules in a metal case and make a few connections) a power amp for my hi-fi using the Purifi Eigentakt modules people are singing the praises of, which don't have integral PSUs. Many appear to use Hypex PSUs with them.

[agedhorse]

Why can a 50W guitar amp sound as loud as a 500 watt bass amp (into appropriate speakers)?

 

1. Hearing is much more sensitive at guitar frequencies than bass frequencies

 

2. Guitar speakers are generally significantly more sensitive at guitar frequencies, than bass speakers are at bass frequencies, often by a factor of 10dB

 

3. Guitar amps are often driven into distortion, which increases the effective compression and average power density.

 

4. Guitar speakers tend to beam more because of the frequencies (including harmonics) that they are reproducing, this increases the on-axis volume.