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V6 firmware: Time to Release the Monster - Speaker Resonance Page

Scott Peterson

Global Moderator
Moderator
I have been working intensely on this and was eager to share it; but wanted to play test it first. Suffice to say, the concept passed muster here. I have to give most of the credit to Jay Mitchell, whom not only took my emails and phone calls; but took the time to talk to me in depth about speaker impedance and it's importance and then provided me the settings to start my own take on this. Thank you Jay, I cannot express my appreciation enough. I got his ok to share this once I was ready... so here we go.

In the Axe-FX II we have a Speaker Resonance Page in the Amp Block. Long story short, it's not a frequency response or PEQ curve; it's the parameter set that makes working with the Cab block IR's dynamic - it is what tells the amp how to react to the speakers via the transformer. There are lots of things going on in the connected amp/cab/speaker that we have control over with the Axe-FX II. The stock settings for these are great; these are where I ended up after lots of listening, questioning, discussion with Jay and research. The result of it all is IMHO a dramatic "Eureka!" moment for all guys that go direct to FOH/FRFR or record direct.

First a little graphical background to make this clear; this looks like small differences... don't be fooled. This is a big difference:

If you look at the Axe-FX II's Speaker Resonance Page you see some settings on the left and a graphical representation of the actual impedance curve to the right. Let's not focus on the values of the curve for now, but the shape. In many of the default curves you see this shape:



Now we focus only on the NF speaker in my cab block formula; it's the 'character' IR. Let's go look at what the curve looks like from Jensen's site for the P12N:



Notice the difference in the *shape* of the impedance curve (**NOT the frequency curve; that's not relevant to this topic**). I want to also point out that the more you look around the net at these speaker impedance resonance curves (just Google that) the more you will see that even vastly different speakers all have essentially the exact same 'curve' shape; the difference is the resonance... and to this discussion and application, the Low Frequency setting in the cab block.

Now look at this revised impedance curve for this amp block:



For reference... here's my cab block at a glance (Note: I am a proponent of the NF/FF mix as you see here):



The speaker resonance curve is NOT a frequency curve, it is NOT a parametric EQ curve; it is a curve that dictates the manner in which the amp dynamically interacts with the speaker - it is the 'map' the amp follows for the speaker response. Other boxes either ignore this aspect or 'bake it in'; the Axe-FX II allows you control over it. This is - not trying to overstate this - perhaps the most important group of settings to how the amp will act and feel at volume. I am very excited about this; I've been gigging this hard for a few weeks and refining it to my taste post Jay's initial settings. Jay approved my sharing this; I am very confident that the investment in effort in trying this out for your amp presets will result in *highly* satisfactory results. You might even smile.

So how does this work on different amp types and speaker cab IR's? Follow the guide below. You can adjust to taste; don't be shy! IMHO, the key is setting everything to what I suggest here; then finding the 'fs' (Free Standing) speaker resonance frequency from whatever NF (Near Field) IR you have in your cab block. Add 10Hz to that number and use that as your starting reference point. The other settings remain the same no matter what speaker you choose (though again, if you tweak it and it sounds/feels better to you... it is better for you!).

Down to Brass Tacks for the Impatient:

Speaker Resonance Tab

Suggested settings:

Low Res Freq: Find the Resonant Frequency of the NF (Near Field Speaker) you use in your Cab block. (Sources are the manufacturer's of the speakers). Add 10Hz to that value.
Low Res Q: 1.556
Low Resonance: 3.55

Mid Res Freq: 726Hz
Mid Res Q: 0.355
Mid Resonance: -1.20db

Hi Freq: 2900Hz
Hi Resonance: 1.56

Cab Block:
NF/FF cab suggestions by amp/tone

Fender (or Fender Like tones): NF) C12N (RW) or whatever you prefer / (FF) JM 112 EMI Open Back

Vox (or Vox like tones): (NF) Top Boost Blue (RW) or whatever you prefer / (FF) JM EMI 112 Open Back

Marshall: (NF) OH 412 SLM G65; though I really go by taste on this, also use the H75 OH a lot / (FF) JM 212 G12-65

Higher Gain:(NF) OH SLM V30 or whatever you prefer / (FF) JM 212 G12-65 (FF)


Cab Block Settings:
CAB MODE - STEREO
MIC (TYPE) – NONE (both)
MOTOR DRIVE - 2.25
PAN L/PAN R – 0.00/0.00 (center)
LEVEL L/LEVEL R – NF cab choice -6.00 db/FF cab choice 0.00 db
ROOM LEVEL/ROOM SIZE – Default settings
AIR/AIR FREQ – Default settings


Reverb:

Use a reverb block and with an expression pedal to control the wet/dry. Use the modifier on the "Input Gain" control parameter of the reverb block to mix in the wet/dry with an expression pedal to get real time control.

Small Room:
Run in parallel
TIME - 1.00 sec. (*short, I do this on purpose)
MIX - 100%
LEVEL – 0.00db
BYPASS MODE - MUTE FX IN
Early Level: -9.00db
Reverb Level: -12db
 

shasha

Fractal Fanatic
I'll have to really dig into this a bit more when I get some time later on, but I couldn't agree more that this is probably my favorite tab. I got a bit of a different route in terms of dialing it in for my taste, I like a lot of bite and I find that more often than not I'm adjusting the mid frequency to around 1700Hz with a fairly sharp Q and probably about 1-2dB of gain. It will cut through the mix like nobody's business and I love the way it sounds and responds with the tone pot. Of course the way that I dial in my patches and the rest of our gear is different so it's one of those personal things, but this is one of the best areas in the unit for capping off a patch IMHO.
 

merlin17

Power User
I'm definitely trying this tomorrow.
BTW: Looking at the Jensen graph wouldn't it be better if the high frequency shape was shelf or bell but at a much higher frequency (like 40kHz)? I know that's not implemented in the Axe (yet)...
 

nater

Experienced
Scott, thanks for all the hard work... I will give this a try tonight fo show! Question, are all JM cabs considered Far Field? I think you mentioned that before but wasn't sure!

Also, you suggest adding 10Hz to the low freq peak, but it appears the LF peak on the Jensen speaker is at 100, but your LF Res is still at 100. Should't that be at 110 then? I'm probably mis-understanding the Jensen graph in the first place, but it appears the LF spike is right at 100Hz.
 
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Rocket Brother

Power User
Great post Scott
The speaker resonance is definitely one of the most important and most overlooked set of parameters in sculpting your tone and getting real amp and speaker interaction going.
I´ve just recently started out experimenting with the speaker resonance myself, and although I still have some tweaking to do, I'm really excited by what it does for my direct tones.
RB
 

Stadanko

Inspired
Definitely gonna spend some time with this one. I am guilty of using this page to control the frequency response, especially the high resonance. Right or wrong, when I drop the curve below 1600Hz and push the amount up my amps tend to really open up without sounding brittle, harsh, or annoying. This is one of the first things tweak with an amp model, all without really getting what this parameter does.

I realize that I may be missing the point of the physics behind it. So, if the resonance not only affects the frequency response but the the feedback and dynamic response as well, I may not be noticing how the feel is changing in relationship to my settings as much as I could if I were to understand this parameter as it is.

Pretty cool, though the tweaking part may become tedious:lol

Thanks for the effort Scott!
 

Funeral

Fractal Fanatic
Thanks a lot Scott and Jay. I will admit that Im a speaker resonance newbie, but Im working on it.
The detailed break down is great. Im going to let my ears rest a few hours from a loud day at work and then I will give all these settings a try.
Thanks again for sharing.
 

Scott Peterson

Global Moderator
Moderator
Scott, thanks for all the hard work... I will give this a try tonight fo show! Question, are all JM cabs considered Far Field? I think you mentioned that before but wasn't sure!

Also, you suggest adding 10Hz to the low freq peak, but it appears the LF peak on the Jensen speaker is at 100, but your LF Res is still at 100. Should't that be at 110 then? I'm probably mis-understanding the Jensen graph in the first place, but it appears the LF spike is right at 100Hz.
Don't pay attention to the chart; pay attention to the published resonant frequency - which for this speaker is 90Hz.

The Graphs are used to illustrate the point only; note that the Editor doesn't display as accurate representation of the curve as the actual graph on the Axe-FX II.
 

kmanick

Fractal Fanatic
thanks Scott (and Jay) I will be testing these settings out
I used to use this tab a lot more in earlier versions of firmware but haven't seen the need lately
( but if it makes the feel more dynamic, well then it's worth checking into)
 

Scott Peterson

Global Moderator
Moderator
I'm definitely trying this tomorrow.
BTW: Looking at the Jensen graph wouldn't it be better if the high frequency shape was shelf or bell but at a much higher frequency (like 40kHz)? I know that's not implemented in the Axe (yet)...
Note that the impedance curve isn't a frequency response curve though. The controls in the Axe-FX II are as they are; you can't get it to shelf or bell like that. Jay's formula - for me - really gets it sounding and feeling right across every amp model I've tried it on (and I've tried most of them).
 

cobbler

Fractal Fanatic
I have a question and it's probably a dumb one while I try to get my head around this. When mixing a NF and FF why do you set the Low Freq Res with the NF manufacturers Resonant Frequency as a reference point? IN other words why not the FF or a average of the two?
 

Scott Peterson

Global Moderator
Moderator
I have a question and it's probably a dumb one while I try to get my head around this. When mixing a NF and FF why do you set the Low Freq Res with the NF manufacturers Resonant Frequency as a reference point? IN other words why not the FF or a average of the two?
This is *strictly* my opinion, YMMV.

I find the FF adds the 'body' to the tone in the equation; the NF adds the 'character'. Much of what folks do NOT like about Direct to FOH/FRFR is what the NF IR is adding to the equation. Notice the levels I have the NF in.

I've tried all sorts of different curves, low end frequency points, etc.. What I am sharing here is just what I've found works best overall IMHO. Jay for instance does not agree with my use of the close mic'd IR's at all. In his opinion, he only uses FF IR's exclusively.

In the end, for my own personal taste, my method as outlined above just sounds and feels better. I really want folks to take this by the horns and try it for themselves. This stuff is key to accurate and true response; it really takes it all a step forward in a tangible and organic way. The key is accuracy to real life; and as Jay has said for years and years, the tools are there. This is my effort to show some light on how to utilize those tools. IMHO.
 

skintone1

Inspired
Scott,
You da man !
That is much appreciated, and I am looking forward to studying this and working with it a bit .
I never understood what the speaker resonance page did before, and it is only thanks to your sharing this kind of information that we can learn this stuff and get the most out of the Axe Fx, so you have my undying gratitude.
 

cobbler

Fractal Fanatic
I have never tried mixing a NF and FF before. I will definitely give it a try and experiment. I love posts like this that give me starting points to areas I would never touch. My question was just one of curiosity and wanting to learn as opposed to questioning your methods or opinion. Heck, I wouldn’t even have a Axe if it wasn't for your sharing nature.

My total experience with IR's has been to just going down the list of RW and OH IR's and experimenting with what I think sounds cool with different patches and documenting it. Again, posts like this beauty inspire me to step out of my comfort zone and experiment more and therefore increase my limited knowledge.

Well done!!!!!
 

Scott Peterson

Global Moderator
Moderator
I'm sure you have, but have you tried "the formula" with a lot of different cabs as well ? giving the same results ? how about when only using NFs ?
I've tried everything I could imagine and keep coming back to the mix I have presented. It just sounds and feels right at volume.

But... if you are a hardcore NF only sorta guy... trust me, this formula will still be essential (in fact, maybe even more so).
 
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