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FM9 sounds different than FM3?

Brett336

Inspired
From what I understand, variable impedance only matters when run directly into certain types of Drive block. Otherwise it doesn't actually affect the sound.
I understand it as an impedance matching between the axe and what is being input into it. Maybe someone else with more credible knowledge can hijack the thread - I'm only a mechanical engineer - Clif?
 

kptkarl

Inspired
Is it just me or does the FM9 sound and feel different than FM3?

I tried identical presets after firing up my fresh FM9, and they sound and feel better to me on the FM9…maybe it’s the secret sauce advertised on the input?

Anyway, both sound and feel amazing, and I am psyched to have the extra foot switches and processing power. 😀
Perhaps it’s the new tubes :tearsofjoy:
 

unix-guy

Legend!
From what I understand, variable impedance only matters when run directly into certain types of Drive block. Otherwise it doesn't actually affect the sound.
No, it is a physical matrix of resistors capacitors on the input and it definitely interacts with your guitar.

Edit:

From the Blocks Guide:

724447FD-5D1C-4D46-BA9A-3F0362DBF7D5.jpeg
 
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rossipedia

Experienced
No, it is a physical matrix of resistors on the input and it definitely interacts with your guitar.

Edit:

From the Blocks Guide:

View attachment 89917
I'm not disputing that. I'm referring to statements Cliff has made saying that it doesn't actually affect the sound except for some of the Drive types.

I could be wrong, I haven't actually played around with it much. I'll obviously defer to Cliff if he chimes in to clarify things.

EDIT

Okay, it looks like changing the impedance only matters if the first non-bypassed block in the chain is modeling an effect box that had a lower impedance...? Am I reading that right?

1633760619956.png
From: https://wiki.fractalaudio.com/wiki/index.php?title=Input_impedance#Auto_input_impedance
 
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unix-guy

Legend!
I'm not disputing that. I'm referring to statements Cliff has made saying that it doesn't actually affect the sound except for some of the Drive types.

I could be wrong, I haven't actually played around with it much. I'll obviously defer to Cliff if he chimes in to clarify things.

EDIT

Okay, it looks like changing the impedance only matters if the first non-bypassed block in the chain is modeling an effect box that had a lower impedance...? Am I reading that right?

View attachment 89919
From: https://wiki.fractalaudio.com/wiki/index.php?title=Input_impedance#Auto_input_impedance
I understand... But this post (linked from your wiki link above) seems to confirm my actual experience, which is that it alters your guitar tone regardless of the first block after the Input:

https://forum.fractalaudio.com/thre...ter-tones-from-the-axe-fx.151997/post-1808756

The part relying on that first block is when you use the Auto setting.

Manually changing the value will make your guitar tone different regardless. Try it.
 

rossipedia

Experienced
I understand... But this post (linked from your wiki link above) seems to confirm my actual experience, which is that it alters your guitar tone regardless of the first block after the Input:

https://forum.fractalaudio.com/thre...ter-tones-from-the-axe-fx.151997/post-1808756

The part relying on that first block is when you use the Auto setting.

Manually changing the value will make your guitar tone different regardless. Try it.
Yeah that makes sense. The wiki feels a bit fuzzy on the topic. Would be great to have this particular feature explained in clearer detail, preferably in the manual.
 

Pete1959

Inspired
My two cents is that when I moved my personal FM3 presets to my FM9, I didn't notice and real difference. Of course my personal presets had "economy" settings for reverbs and IRs. So when I kicked those up a notch as well as tweaking and even adding blocks with my newly found CPU, then yes, the FM9 sounds better.
 

Stratman68

Axe-Master
so you guys are going to make me get my FM3 out of my bedroom and set it up in my little studio?
Honestly, I "sense" a difference but I cannot be sure if it isn' the fact that now have all these buttons and switches and don't have to tap dance(which I was\am fine with).
I also changed IRS to UR and changed reverb settings. So, who knows.........Love them both!
 

brokenvail

Fractal Fanatic
My two cents is that when I moved my personal FM3 presets to my FM9, I didn't notice and real difference. Of course my personal presets had "economy" settings for reverbs and IRs. So when I kicked those up a notch as well as tweaking and even adding blocks with my newly found CPU, then yes, the FM9 sounds better.
I loaded up my FM3 patch. Switched everything to heighest Rez/ density and I def heard a difference that way.
 

rossipedia

Experienced
Anybody done a null test yet?

If not I have all 3 units set up, might whip up a quick session comparing the same preset in all 3 and null checking them against each other.
 

blaggers

Experienced
When I loaded some of my FM3 presets on my new Axefx3, some of them sounded better, some sounded identical.
Ive tried this as well (FM3 to AXE III - using same factory presets), and sometimes the AXEIII sounds worse - I noticed this on the "Brit 800" preset, FM3 sounds better.
 

rossipedia

Experienced
Id be interested in a Brit 800 comparison.
the Brit 800 preset is actually quite a bit different between units from what I can tell.

What I'll probably do is just do a single amp + cab block (Brit 800 / some stock cab) to minimize variance between units.
 

rossipedia

Experienced
Aight whipped up some null tests. They don't completely cancel out due to the non-deterministic nature (ie: random elements) of Fractal's amp modeling, but the volume does drop quite significantly. Interestingly, there's a lot more low-end difference between the FM3 and the AxeFX III than I expected, which is weird because the other two tests don't exhibit this.

The first 4 tracks are standalone: The DI I used, followed by the FM3, FM9, and AxeFX III tracks. Then there are 3 null tests.

At the beginning of each track you'll hear a blip. That's a metronome tick I used to sample-align the clips when I was doing the null tests. Fun fact, the reamp latency of each unit is exactly as you would expect: AxeFX is quickest, followed by FM9, followed by FM3. I'm assuming it has to do with the CPU power of each unit.

Alignment Tick.png

I've also attached the preset I used. Super basic, just a Brit 800 block going into a stock cab. I set the IR Length to 1024 for each clip.




Conclusion

Honestly? A/B-ing the standalone clips I can't tell or feel a difference. They sound pretty much identical, at the very least close enough to be interchangeable, in my personal opinion.
 

Attachments

  • Brit 800 Null Test.syx
    24.1 KB · Views: 2

blaggers

Experienced
Thanks for that comparison - its shown me that there is a difference between them in my setup that you dont show - maybe due to the ABY switcher changing the impedance seen by the guitar- will do a direct to reaper recording comparison between them.
 

Rex

Legend!
Thanks for that comparison - its shown me that there is a difference between them in my setup that you dont show - maybe due to the ABY switcher changing the impedance seen by the guitar- will do a direct to reaper recording comparison between them.
ABY switches — particularly the ones with internal transformers and such — can present different loads at different inputs/outputs, making things sound different.
 
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