I'm not really sure what the difference is dialing in a sound with an IR vs using a Dynacab.
I think it’s mostly interface preference. Some people like being able to drag the mic around.
The Dyna-Cabs themselves use experience learned from many years of FAS making IRs, a different pre-amp, probably some mics and cabs and speakers they’ve acquired in the interim that they like more, etc., so there are some differences in the sound of two similar cabs+speakers+mics.
How do you find the IR that you like for a particular tone?
I search for cabs with the speaker and mics I want, then audition them to find the mic position I want.
Do you find the IR first then play with the tone controls on the amp?
Nope, it’s interactive, I pre-adjust the amp for the gain structure I want, then find the cab I think would fit, then bounce back and forth fine-tuning both until I’m happy. The Dyna-Cabs make it easier to fine-tune the mic position because I don’t have to load a different IR.
I have some IRs in Cab blocks I like, so I can copy/paste them around or just stick them in the Block Library and I don’t need to go through the process again. That is true for both types.
This is why I don't see much different. I set the amp to what I think it should be (usually neutral) dial in the Dyna Cab and then go back to the tone controls to make adjustments. I have found that it doesn't really take that long to dial in the mics.
They are different controls with different effects on the signal though.
The amp tone controls affect how the Amp model generates the sound and can affect the gain and other aspects of the sound coming from that block. They can turn a sine wave into a square wave basically.
The Cab block’s basic controls don’t have that effect. In an IR player, IRs are more like an EQ curve that only adjust the frequency response of the wave coming from the amp. In the Cab block, kind of a glorified IR player, there are some secondary controls that can change the waveform but they’re in the preamp section.
Yes, the Cab block can emphasize the bass or highs depending on mic position and EQ curve, but that doesn’t replace the controls in the Amp block. I think of it this way: A Fender Deluxe has a certain sound, and we can adjust the tone controls for its traditional sound then leave them alone. We can then connect it to a 1x8” cab or a 1x15” cab and get radically different bass and treble response. Adjust the amp’s tone controls with either cab connected and the sound will change but not as much, however the amp’s behavior will change. It might get flubby or tinny but it will still have the overall sound of the speaker. Similarly do that with a Marshall or Mesa, the two sections affect the sound differently.
