I have seen endless posts from users who are frustrated with or confused about full range speakers, so I slapped this together. I'm not a technical expert so this is focused on the basics.
If you search and read you'll dig up a lot more info than this post. But for those getting started, I'm no different than anyone else. I face the same challenges when it comes to getting great tone direct-to-PA. These are a few things I've seen and learned along the way.
A full range powered PA speaker or floor monitor is not identical to a guitar speaker/cabinet.
It sounds stupidly obvious, but this is the most common complaint I've seen on the axe-fx forum. Users hook it up, play and scratch their heads wondering why it doesn't sound the same as their guitar cabinet. A full range "flat response" powered speaker (FRFR for short) is a completely different animal and the sooner you accept that, the less perplexed you'll be.
Long story short, I recommend a different mind set: Stop thinking about what an unmiced cabinet on stage sounds like. Replace that instead with what a great RECORDING of a guitar rig sounds like. Reference your favorite recordings and get THAT sound into your head. This is your starting point for dialing sounds with a full range speaker.
And--reality check--this is what everyone else hears when they're out in front of a fully miced band or listening to a CD. Give your audience a killer recorded-guitar-cabinet-sound, and you'll be amazed at how many compliments you'll get about your tone from fans, strangers, and soundtechs.
YES you can use a powered speaker and the axe-fx to get the sound of an unmiced guitar cabinet on stage, or get it using an actual guitar cabinet. If that's your goal, stop reading this and search for how to do that. There's plenty of info and various approaches to achieving that. But remember....an unmiced guitar cabinet isn't what the typical listener knows as a great guitar tone.
Don't buy cheap gear.
Do you want to be really frustrated? Buy a budget FRFR powered speaker. You'll be shooting yourself in the foot over and over trying to overcome these basic problems.
1. The high end driver is crispy, brittle, overdone,
If the high end driver isn't smooth you'll endlessly battle the "icepick in the ear" problem on stage and go through hell trying to dial it out without muddying up the sound. IMHO even the JBL prx series, and Mackies from approx the last 7 years have this problem...and it's gets much, much worse with cheap gear.
2. The sonic performance drastically changes at different volumes.
The better the gear, the better it will sound at low AND high volumes, and that is critical for dialing the axe-fx. High quality FRFR speakers make dialing for different volumes A LOT easier. Technically, no speaker sounds the same at low and high volume. And because of that it's never easy to get a guitar patch sounding good at low/high levels. If it's never easy... why in the world make it 10 times harder just to save $200-$300 on a FRFR speaker? You'll spend a couple grand in man-hours trying to compensate for this one fact alone, and if the high end driver isn't high quality, it'll take a lot longer.
3. Frequency separation and balance are poor.
If you wanted to paint a picture, would you close the blinds and turn on a dingy, dim yellow bulb for light, or would you get as much natural ambient sunlight as possible?
With the axe-fx you are painting a sonic picture of a killer tone inside your head. The better your "light" and the cleaner your "canvas", the more accurate the colors will be and the more you will see what you're doing. This is what a high quality FRFR can do for you. There is no substitute for good ears and experience, but a high quality FRFR will make the journey a lot less painful.
Dial tones on the FRFR speaker(s) you perform through & do it at moderate and gig level volumes
Headphones and quiet bedroom dialing are not going to work. Dialing at different volumes is one small reason why great recordings sound good on different systems at different volumes.
HOWEVER, this doesn't mean that you can dial your axe-fx on studio monitors and expect it to translate to PA gear at gig volumes. Why? because some very talented dudes engineered/produced/mastered those great recordings, and they used some of the best equipment in the world to get those tones to translate, and they listened to their work through different systems. Does that mean you can do that yourself with just an axe-fx & studio monitors?
I tried and failed more than a couple times. :
What I do now is listen to a guitar recording through nice studio monitors and try to get the same sound through FRFR speakers at a few different volumes. I also reference across different FRFR speakers. I have two small PA systems and and a powered floor monitor so I have a the opportunity reference my tones across a pair of powered PA speakers, a passive bi-amp PA system, and a floor monitor with a coaxial driver.
You can do the same if you have friends with PAs or powered speakers, or you can take your FRFR/axe-fx rig to a music store and A/B across the PAs they have on display. It's worth the time & effort. You'll learn a lot.
Learn how to dial axe-fx versions of real life gear by researching artists, rigs and tones.
If you're going to go beyond plug and play, you need to do this. I am amazed at how many users expect the axe-fx to come pre-loaded with the tones they want. They want to flip a switch and get a specific tone that's in their head without having a clue what gear was used and how it was dialed.
The axe-fx and a great FRFR speaker aren't going to magically implant this knowledge into your musical skull. YOU have to put it into your head and dial it into the axe-fx before you hear it coming out of a FRFR speaker. And if you don't buy a quality full range speaker, you still won't hear it.