how do you set your amp flat?

Most modern amps have active EQs that can cut and boost frequencies, so the center (0dB) setting is the right one.
Passive EQs, like on old Marshalls, can only cut frequencies. So you can flat EQ by turning the knobs up to full (this is the secret behind the English Setting btw).

Keep in mind though, that with most amps a flat EQ still won't give you the the true bass signal.
Most amps, especially those with a tube in the preamp section also have a fixed EQ circuit, because one single tube is not enough to give the impression of tube sound (not are not 'driven' hot enough for that anyway). That EQ is always enabled, no matter how you set the EQ.

 

Either they have more powerful amps or don't need to play as loud as you... or both.

 

The Hartke puts out around 240W @ 8 Ohm, I don't know if Hartke's specs are accurate or a little optimistic.
Your 15" probably is not a very loud cab too.
That might explain it.

 

it doesnt always work if you set your amp to 0. some knobs start at 0 and go to 10, so setting them at 0 would mean you dont hear anything

to set it flat, put all the knobs in the center position so they are pointing straight up. then the tone will be just flat, no boosted or cut frequencies.

 

Using your eq to get more volume is not really a good thing. You are trying to "cheat" to make the amp put out more than it's designed to. This could cause clipping, which could ruin a speaker.

EQ screws up your sound to begin with. The way eq works is that it shifts certain frequencies out of phase which causes phase cancellation and reduces the volume of that frequency. The more eq you use, the more messed up the sound will get. It's best to use small amounts of eq only where it's needed rather than eq'ing everything or making a big smile or frown or whatever. It is very possible to cause the sound to get muddy by using too much eq, even if you are only boosting frequencies that are associated with making the sound more clear. That's because of the phasing. This is true whether we're talking about a five-band eq in a car stereo or a $1400.00 KlarkTeknik 1/3 octave equalizer.

I recently read a post where someone said that if you have to turn your volume much more than halfway up to be heard, it's time for a bigger amp. I think that's a pretty good rule.

 

I can confirm that from my own experience.
'bigger amp' meaning at least double wattage.

However volume is not only determined by amp power, efficiency and frequency response of the speaker is important too - in fact even more important. E.g. the same amp head will sound louder with a 410 cab than with a 115 (in most cases).

In your case adding a 410 will for sure make a big difference because you will have more speaker surface area and you will utilize the full 350Watts (instead of ~200W now)

Matthias

 

Right. I should have said "louder amp."

 

I not too familar with Hartke amps but if it has a Gain or pre gain pot (could be just a volume pot with a master volume) you may need to turn this up higher before turning up your volume.(Not so much that you would be clipping your cab, though)

Most amps are set up to set your gain to prevent clipping and then adjust your volume to desire loudness without tearing up your speakers.

If yours doesn't or you've already check this, you may want to look into something a bit bigger.