Spkr Res Freq - Intelligent use of?

[joegold]

Just trying to wrap my head around how to use this parameter intelligently or if I should just continue to leave it alone.

The manual says that each amp Types defaults to a value for this parameter that is correct for the speaker that was used in the original amp.
So the Amp Block simulates some sort of an impedance interaction as if it was pushing a speaker that has that default Spkr Res Freq value.
I hope that's correct.

What I'm wondering is if there is any benefit to changing this value to the value of the speaker that you're actually using in your system to monitor the Axe with, assuming that you know the correct resonant frequency of your speaker.

In my case, I'm using EVM-12Ls being driven by an ART SLA1 power amp.
Electrovoice publishes a spec of 55hz as being the T/S parameter resonant frequency of the EVM-12L.

So... If I use a Spkr Res Frq value of 55hz in the Amp Block, will the virtual amps behave more like they are driving an EVM-12L?
Is that the basic idea?
Or have I mixed some or all of this into utter nonsense?

Sometimes I do think that I hear a slight benefit to using 55hz as he value for this parameter, but it's very subtle and I'm probably fooling myself.
I usually just leave this parameter alone.

 

[Jay Mitchell]

The manual says that each amp Types defaults to a value for this parameter that is correct for the speaker that was used in the original amp.

Correct.

So the Amp Block simulates some sort of an impedance interaction as if it was pushing a speaker that has that default Spkr Res Freq value.

It simulates the effect that the load presented by the speaker impedance to the power amp has on the response of the amp. Depending on the amp's design, this effect could vary from huge to just audible or even inaudible.

What I'm wondering is if there is any benefit to changing this value to the value of the speaker that you're actually using in your system to monitor the Axe with,

There is a definite benefit to setting the value to the resonant frequency of the cab being modeled. If you're not using cab sims and playing through a guitar speaker, you could make the amp sim behave more like a physical amp driving that particular cab by adjusting the resonant frequency appropriately. One significant caveat: the resonant frequency of a speaker/cab combination is not the resonant frequency that is published in the speaker's data sheet. It is, without exception, somewhat higher. Open back and ported cabs can generate multiple resonant peaks in the impedance vs. frequency curve.

Electrovoice publishes a spec of 55hz as being the T/S parameter resonant frequency of the EVM-12L.

The actual resonant frequency with the speaker in the cab you're using will be somewhat higher. I'd suggest trying a setting of ~65Hz in the amp sim.

So... If I use a Spkr Res Frq value of 55hz in the Amp Block, will the virtual amps behave more like they are driving an EVM-12L?
Is that the basic idea?

That's the basic idea.

Sometimes I do think that I hear a slight benefit to using 55hz as he value for this parameter, but it's very subtle and I'm probably fooling myself.

Depends on the amp sim. The parameter will have a much greater effect in sims with no negative feedback (e.g., Class A) than it will if your sim has a lot (IOW, high setting for the "Damp" parameter).

I usually just leave this parameter alone.

Try turning Damp to zero and then fooling around with it. You'll get an idea of what it does.

 

[joegold]

Electrovoice publishes a spec of 55hz as being the T/S parameter resonant frequency of the EVM-12L.

The actual resonant frequency with the speaker in the cab you're using will be somewhat higher. I'd suggest trying a setting of ~65Hz in the amp sim.

Understood, mostly.
Thanks Jay. I'll try 65hz and the other things you suggested.

See?
We can get along after all.

 

[electronpirate]

The manual says that each amp Types defaults to a value for this parameter that is correct for the speaker that was used in the original amp.

The question is, if these are 'paired' when modeled, where do we find information on what speaker was used with the original amp? AC30's are easy, even the Fenders, but JCM800? Plexi? SLO?

Just curious.

Ron

 

[guitarnerdswe]

The manual says that each amp Types defaults to a value for this parameter that is correct for the speaker that was used in the original amp.

The question is, if these are 'paired' when modeled, where do we find information on what speaker was used with the original amp? AC30's are easy, even the Fenders, but JCM800? Plexi? SLO?

Just curious.

Ron

You should vary the value according to what the speakers in the IR you're using is. Original speakers for JCM800 would be the G12T75, the SLO would be Eminence Legends or 12Xs.

 

[Scott Peterson]

AFAIK remember that the speaker's published resonance is measured in free space or on a baffle, not in a cab. The volume and design of the cab will affect the resultant end speaker resonance. That's what Jay said, but didn't detail above.

This is one of the main reasons the same speaker can sound so different when mounted in different cabs.

 

[electronpirate]

The manual says that each amp Types defaults to a value for this parameter that is correct for the speaker that was used in the original amp.

The question is, if these are 'paired' when modeled, where do we find information on what speaker was used with the original amp? AC30's are easy, even the Fenders, but JCM800? Plexi? SLO?

Just curious.

Ron

You should vary the value according to what the speakers in the IR you're using is. Original speakers for JCM800 would be the G12T75, the SLO would be Eminence Legends or 12Xs.

See, this is the sort of stuff that would be beneficial. It's expected that it's just 'known' that the cabs sold with them come with that (yes, I know a few of them, but making a point here). Certainly it's researchable, but might be time for a WIKI that outlines that. Or a set of presets all at default with the cab it should use. I think it would go far to alleviate so many of the 'I can't get it to sound good' posts we see every day.

IMO.

 

[tgunn]

Would it make sense to have a feature whereby the amp resonance value would be automatically set to what the resonant frequency of say, cab1 is?
E.g. if you could set the frequency in the amp block to either a Hz value, cab1 or cab2. For sake of simplicity assume that a mono cab is selected

 

[javajunkie]

Would it make sense to have a feature whereby the amp resonance value would be automatically set to what the resonant frequency of say, cab1 is?
E.g. if you could set the frequency in the amp block to either a Hz value, cab1 or cab2. For sake of simplicity assume that a mono cab is selected

The blocks are not aware of other blocks contents (at least that I can tell). It would probably require a significant change in the way the block objects are programmed and could potentially cause patch change time to go up as the speaker res parameter would basically have to be dynamic instead of stored as a parameter. Plus it wouldn't have a clue what is loaded in the user cabs.

 

[javajunkie]

Certainly it's researchable, but might be time for a WIKI that outlines that. Or a set of presets all at default with the cab it should use. I think it would go far to alleviate so many of the 'I can't get it to sound good' posts we see every day.

IMO.

sounds like you have a project

 

[electronpirate]

Certainly it's researchable, but might be time for a WIKI that outlines that. Or a set of presets all at default with the cab it should use. I think it would go far to alleviate so many of the 'I can't get it to sound good' posts we see every day.

IMO.

sounds like you have a project

I was afraid someone would call me out on this Sean!

Damn.

As far as the research (yes, I was thinking about it), the problem I might have is that historically, an amp might have one particular (or several) speaker(s) associated with it. But I'll have to parse out what CLIFF used when he modeled the amp. Guru's help out here, since would the Spkr Res Freq give me a clue on which one it might be?

Ron

 

[javajunkie]

Certainly it's researchable, but might be time for a WIKI that outlines that. Or a set of presets all at default with the cab it should use. I think it would go far to alleviate so many of the 'I can't get it to sound good' posts we see every day.

IMO.

sounds like you have a project

I was afraid someone would call me out on this Sean!

Damn.

As far as the research (yes, I was thinking about it), the problem I might have is that historically, an amp might have one particular (or several) speaker(s) associated with it. But I'll have to parse out what CLIFF used when he modeled the amp. Guru's help out here, since would the Spkr Res Freq give me a clue on which one it might be?

Ron

All you really need to figure out is the resonant freq of the speaker cabs on the Axe-fx. You would then just set the parameter to the cab sim you are using.

 

[tgunn]

Would it make sense to have a feature whereby the amp resonance value would be automatically set to what the resonant frequency of say, cab1 is?
E.g. if you could set the frequency in the amp block to either a Hz value, cab1 or cab2. For sake of simplicity assume that a mono cab is selected

The blocks are not aware of other blocks contents (at least that I can tell). It would probably require a significant change in the way the block objects are programmed and could potentially cause patch change time to go up as the speaker res parameter would basically have to be dynamic instead of stored as a parameter. Plus it wouldn't have a clue what is loaded in the user cabs.

Yeah figured this much. As for switching between these patches I was more thinking of this feature to be dynamic only while editing and as soon as the patch is stored, the actual matching frequency would be stored with the patch. I realize though that this is uncharted territory (blocks being aware of other block settings) and would no doubt be a huge undertaking with perhaps not so much reward.

 

[Sgt.Alexx]

A cool way to use this is to just pick a palm muted low E while turning the "knob". Try to hear where the most natural bottom is. Just like tuning a drum. Eventually you'll hear the natural pitch of the drum. I find this parameter to do something of the same with the bottom frequencies.

Nerdy, but cool

 

[rsf1977]

if anyone can post a video on how to decipher the resonant frequency once they have a good method, that would be the bees knees.

 

[electronpirate]

if anyone can post a video on how to decipher the resonant frequency once they have a good method, that would be the bees knees.

Be easier to find someplace that lists the Resonant Freq of each speaker we have modeled.

(I'll bet Jay has this stuff hanging around in his cranium...this stuff is his wheelhouse.)

Ron

 

[VegaBaby]

Be easier to find someplace that lists the Resonant Freq of each speaker we have modeled.

(I'll bet Jay has this stuff hanging around in his cranium...this stuff is his wheelhouse.)

Ron

Wondering if RedWire have a list of their IRs' Res Freqs...that would be a huge help already.

 

[Matman]

What is the effect on the emulation if this value is set "incorrectly"?

 

[Jay Mitchell]

What is the effect on the emulation if this value is set "incorrectly"?

You'll get the response of the amp driving a speaker with a resonant frequency other than that of the speaker that is represented by the IR you're playing through. Whether that difference is even audible depends on the resonant frequency itself (much below 80 Hz has relatively little effect on guitar frequencies) and the virtual design of the amp sim (e.g., higher values for Damp will reduce the effect).

The justification for getting this "right" is getting the closest possible match to the physical cab you're simulating. There's nothing to say it won't sound better set to some other frequency.

 

[Matman]

There's nothing to say it won't sound better set to some other frequency.

Thanks, Jay. I've always used my instincts to set it, or left it at the default value.