Spkr Res Freq - Intelligent use of?

I just had a look around and it seems that most manufacturers list the Res Freqs on their websites, so it should be fairly easy to find the ones people are looking for. I found mostly all of the ones I'm using in a matter of minutes...

Question for Jay...

You said the frequency is in the real world a bit higher. Is there a rough rule of thumb by how much ?

Interesting topic this is :cool:
 
VegaBaby said:
You said the frequency is in the real world a bit higher. Is there a rough rule of thumb by how much ?
Click to expand...
No. The mathematical formula requires information that is not provided in speaker data sheets. The effect goes as the inverse of the size of the box, i.e., the smaller the box, the greater the increase in resonant frequency.
 
Jay Mitchell said:
VegaBaby said:
You said the frequency is in the real world a bit higher. Is there a rough rule of thumb by how much ?
Click to expand...
No. The mathematical formula requires information that is not provided in speaker data sheets. The effect goes as the inverse of the size of the box, i.e., the smaller the box, the greater the increase in resonant frequency.
Click to expand...
Ahh, ok, got it.

So if Celestion list a V30 with 75hz and you'd put that in a 1x12 box you'd have to adjust slightly higher than 75hz (on the Axe's amp sim) and putting the same speaker into a 4x12 would go the opposite, right ?

At least these are good ballpark figures to start listening for sweetspots. Interesting area I never explored before. Thanks Jay for clearing it up and thanks Joe for bringing it up !
 
Jay Mitchell said:
VegaBaby said:
You said the frequency is in the real world a bit higher. Is there a rough rule of thumb by how much ?
Click to expand...
No. The mathematical formula requires information that is not provided in speaker data sheets. The effect goes as the inverse of the size of the box, i.e., the smaller the box, the greater the increase in resonant frequency.
Click to expand...

Actually after some reading, my gerbil sized grey matter understood this.

So I have a question. If Cliff modeled an amp, and assigned a SRF to it, would only Cliff be able to answer what the ORIGINAL speaker (cab model?) used was? Certainly I understand working it backwards, using whatever speaker you like, and sync'ing up the resonant frequencies, but I like the idea of getting it to what Cliff hears when he pronounces an algorithm 'production ready'.

If this seems overly anal, it is.
 
VegaBaby said:
So if Celestion list a V30 with 75hz and you'd put that in a 1x12 box you'd have to adjust slightly higher than 75hz (on the Axe's amp sim) and putting the same speaker into a 4x12 would go the opposite, right ?
Click to expand...
No. First, a 4x12 box with four speakers in it has the exact same effect on resonant frequency as a 1x12 box of one fourth the volume with only a single speaker. Second, placing a speaker in an enclosure never reduces the resonant frequency. The effect is always an increase, and the only thing that varies is the amount by which the frequency goes up.
 
Jay Mitchell said:
VegaBaby said:
So if Celestion list a V30 with 75hz and you'd put that in a 1x12 box you'd have to adjust slightly higher than 75hz (on the Axe's amp sim) and putting the same speaker into a 4x12 would go the opposite, right ?
Click to expand...
No. First, a 4x12 box with four speakers in it has the exact same effect on resonant frequency as a 1x12 box of one fourth the volume with only a single speaker. Second, placing a speaker in an enclosure never reduces the resonant frequency. The effect is always an increase, and the only thing that varies is the amount by which the frequency goes up.
Click to expand...
Right. That actually makes sense. Just out of curiosity, and that's probably nonsense, but could there be an enclosure which meets the exact SRF of a speaker's specs (meaning no alteration) ?
 
VegaBaby said:
Right. That actually makes sense. Just out of curiosity, and that's probably nonsense, but could there be an enclosure which meets the exact SRF of a speaker's specs (meaning no alteration) ?
Click to expand...
No.
 
Jay Mitchell said:
VegaBaby said:
So if Celestion list a V30 with 75hz and you'd put that in a 1x12 box you'd have to adjust slightly higher than 75hz (on the Axe's amp sim) and putting the same speaker into a 4x12 would go the opposite, right ?
Click to expand...
No. First, a 4x12 box with four speakers in it has the exact same effect on resonant frequency as a 1x12 box of one fourth the volume with only a single speaker. Second, placing a speaker in an enclosure never reduces the resonant frequency. The effect is always an increase, and the only thing that varies is the amount by which the frequency goes up.
Click to expand...

Does it matter if the cab has an open back? Does materials of the cab, padding etc play a role?
 
This is a really interesting thread.

Jay said "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"

Probably a stupid question but if I'm blocking at around 100hz with a PEQ after the cab block (as I understand a lot of people do too), will the resonance setting have any effect at all?

Thanks
 
Nic said:
if I'm blocking at around 100hz with a PEQ after the cab block (as I understand a lot of people do too), will the resonance setting have any effect at all?
Click to expand...
I can think of one way to find out....
 
Jay Mitchell said:
VegaBaby said:
You said the frequency is in the real world a bit higher. Is there a rough rule of thumb by how much ?
Click to expand...
No. The mathematical formula requires information that is not provided in speaker data sheets. The effect goes as the inverse of the size of the box, i.e., the smaller the box, the greater the increase in resonant frequency.
Click to expand...

mr_gumby.jpg


My brain hurts!

Interesting topic nonetheless, so keep the questions coming!!! Just need another week or so to get the summer out of my head, so I can get a grip of anything of this.

@Jay: does it depend just as much on HOW the inner of the cabinet is built as well? I´m thinking of wood selection, the thickness of the selected wood, cabinet construction etc...

If so, I start to realize why it may not be that easy to even come close to set a ROUGH rule of thumb. That would also explain why no one has done it... or why the speaker manufacturers doesn´t bother to provide that kind of information in their speaker data sheets (because they simply don´t know where the user end up mounting his speaker).


/Mike
 
Depends on the Q or slope you're blocking at. If the slope is extremely steep then it won't matter but for slopes like 6db/octave it can matter.
 
miketheman said:
@Jay: does it depend just as much on HOW the inner of the cabinet is built as well?
Click to expand...
No. Depends on the internal volume only. This is all Intro to Acoustics 101 stuff. Much of it is also in the chapter on loudspeakers I authored in Glen Ballou's Handbook for Audio Engineers.
 
Seems to me like the SRF is a very complex dynamic relationship that's almost impossible to calculate with any accuracy at all unless you have the cabinet in question right in front of you along with a bunch of sophisticated test equipment.
This gets even more complex and unpredictable when you're only dealing with IRs of said cabinet(s).

I think that my inclination to simply leave this parameter alone, for the most part, is probably the way to go, for me.

Any audible differences to my tones that I've achieved by tweaking this parameter have been extremely subtle, but I've not experimented extensively with it.
And I'm not running FRFR most of the time.

Thanks to Jay though I now have a bit better understanding of what it does and why it makes sense, for the most part, to just leave it alone.
------------
Postscript
Hmm.
After actually spending a couple of minutes with my Presets using Jay's suggestion of a value of 65hz for this parameter when using my EVM-12L, I can hear that it actually does tighten up the tone albeit very subtly.
It's an effect that I would normally associate with higher values of the damping parameter in that the bass notes seem a bit less "flubby".
It's especially noticeable and beneficial on my cranked Deluxe Preset where the master is cranked. It really tightens up the bottom end and allows me to run the Bass parameter a little higher adding body to the sound without it getting flubby.

I may end up tweaking the SRF after all in my Presets.
 
Plankis said:
So, what res freq would a mesa oversize 4x12 or a Uberkab have?
Click to expand...

I have no idea what the resonant frequency of those cabs would be, but I can guarantee that the resonant frequency of the drivers loaded into either cab will be higher than the resonant frequency of the drivers in free air.
 
I did some quick testing today. Randomly chose a MKIV clean with a RedWire Twin, Jensen C12 speaker. Jensen list the SRF of the C12 at 112hz. Setting the amp sims SRF from 95hz to around 112 made very very subtle changes. I liked 114 actually. It seemed that the whole frequency spectrum was a bit more 'even'. I'm not sure if that's the effect that can or should be expected, maybe my ears just played tricks on me, but I'll play around with it some more...
 
It looks to me like Cliff has already set the SRFs in the Amp Block to default values that are slightly higher than the published resonant frequencies of the speakers used in the original amps.

In my case, since I'm using an EVM-12L, it might make sense to alter the default SRF values because none of the amp sims appear to have been made with an amp driving an EVM0-12L in mind.

I can't see the reason for altering the default SRF values unl;ess you're using a cab sim that is drastically different from the type of speaker used in the original amp, or unless you're in a situation like mine where you're monitoring the Axe through a guitar speaker with a known resonant frequency.
And even then it's questionable whether or not altering the value(s) makes any sense.
For example
Do I want the Deluxe Verb sim to interact dynamically with its virtual speaker as if that virtual speaker was an EVM-12L?
Maybe yes and maybe no.
It might sound more musical for the programmed virtual speaker interaction to remain as authentic as Cliff programmed it to be and for me to just let my power amp and speaker do their own thing.

Again, it's a parameter whose effects are pretty subtle, unless you're using lots of simulated power amp distortion.
 
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