Modifying Speaker Frequency Range - Amazing & Accurate Results

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mhanton777

New Member
A friend who also has an Axe-Fx II XL+ recommended that I edit the Cabinet Block - PG2 and modify the LOWCUT FREQ and HICUT FREQ parameters to reflect the correct values. I got the values from the Celestion website and applied them. All I can say is what a Blessing! Try It!

Example: Celestion Heritage Series G12M
LOWCUT FREQ = 75.0 Hz
HICUT FREQ = 5000 HZ
 
This has become one of my go to things to do first when starting a new patch. It tightens up the sound by cutting down on the boominess on one end and hiss/fizz on the other.
 
The Last Romantic said:
Isn't that information already being applied in the actual IR itself, though?
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It is interesting due to the fact that most speaker manufacturers give their specs in an anechoic chamber or set in earth. So those ideal specs might not match as most of us who capture ir's of speakers mounted in cabinets experience. The cabinet changes the frequency response due to the resonance of the cabinet and its porting. Also the room you are capturing the ir in tilts the response from that ideal, even with a close mic. You also have manufacturing tolerances that will vary this slightly. So what is published as the frequency response may vary from what is the response of that speaker mounted in the cabinet that an ir producer is capturing.
 
I've just made a standard practice of Low Cutting my Cabinet block at 85 and Hi Cutting it at 6500. I have not gone down as low as 5000 though.....although I am sure that it is perfectly fine around that range as well. Most guitars are going to sit in that 85-1500 range fundamentally, but the overtones will go up to 6000 or so, as well as going down below 85. However, when the sound engineer gets a hold of your signal at the board, they will most likely cut you around 100 to leave room for the bass and kick, and will most likely cut you about 4500-5000 to get rid of that harshness and leave room for the keys. cymbals, and airiness to vocals. SO..... I would guess doing a cut at 75 and 5000 in your cabinet block will be just fine and send them the signal they want. The question though is....where is your cabinet block in your signal chain? Is it the very last thing before it goes out of the magic black box? Or do you have delays, reverbs, modulation, etc... after it? I have always been of the mindset that if its not last in the chain(like it would be in an analog rig setup) then it is just controlling what you feed the effects after it. There can always be regeneration of those frequencies you are trying to cut in the cab block by those effects that are after the cab. They can regenerate those overtones based on where you put your lo and hi cuts on those effects. I hope that all made sense.......just something to think about. I don't claim to be a sound genius so I could be wrong about all this, just sharing thoughts and ideas I have had.
 
ssmorga78 said:
I've just made a standard practice of Low Cutting my Cabinet block at 85 and Hi Cutting it at 6500. I have not gone down as low as 5000 though.....although I am sure that it is perfectly fine around that range as well. Most guitars are going to sit in that 85-1500 range fundamentally, but the overtones will go up to 6000 or so, as well as going down below 85. However, when the sound engineer gets a hold of your signal at the board, they will most likely cut you around 100 to leave room for the bass and kick, and will most likely cut you about 4500-5000 to get rid of that harshness and leave room for the keys. cymbals, and airiness to vocals. SO..... I would guess doing a cut at 75 and 5000 in your cabinet block will be just fine and send them the signal they want. The question though is....where is your cabinet block in your signal chain? Is it the very last thing before it goes out of the magic black box? Or do you have delays, reverbs, modulation, etc... after it? I have always been of the mindset that if its not last in the chain(like it would be in an analog rig setup) then it is just controlling what you feed the effects after it. There can always be regeneration of those frequencies you are trying to cut in the cab block by those effects that are after the cab. They can regenerate those overtones based on where you put your lo and hi cuts on those effects. I hope that all made sense.......just something to think about. I don't claim to be a sound genius so I could be wrong about all this, just sharing thoughts and ideas I have had.
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I thought thought about this from time to time but I can't help but think can the delay pump out 20000k if I only feed it 6500?
 
brokenvail said:
I thought thought about this from time to time but I can't help but think can the delay pump out 20000k if I only feed it 6500?
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Lol..... I don't mean its going to be anything as extreme as that!!! Well, unless you have the Hi Cut set at 20000 and get some infinite repeats going that start oscillating........then, possibly if you let the delay run away.
 
for years I did 120/6 or 7k. I read the metallica tech say that there is some harmonic content all the way up to 15k so I switched to that for maybe the last year or so. I recent bought some cab packs and found them on the bright side so I am back down to some where between 5-7k can't remember off hand.
 
Adjusting cab high and low cutoffs is one the few things (maybe the only thing) that I consistently do in every single patch I make. Use your ears! There is definitely a difference, and it becomes more pronounced when playing gig level. Cutting down those highs makes it feel more organic, like a real guitar cab as opposed to a processed sound.

I vary the values depending on how it sounds, typically in the range of 6200Hz to 8800Hz for the high cut. An older lo-fi type of sound (e.g. Fender Champ) can probably get away with lower value for the high cutoff- if I liked that sound I might experiment with the 4k to 6k range. I typically use low cutoff in the range of 72Hz to as high as 180Hz, but mostly around 110Hz. This enables you to turn up more bass in the amp to affect edge-of-breakup tones, without it getting too boomy. Sometimes I muck with the low frequency peak in the speaker tab on the amp too, as part of balancing the "girth" or bassiness of the tone without causing too much actual booming bass.

I do typically put most chorus, delay, phaser, flanger, reverb after the cab and that can add higher frequency overtones. Occasionally I will put something after the amp before the cab if I want the cab filtering to tame higher frequencies of that block. I only put stuff before the amp if I want the exaggeration that comes from the amp gain stages, e.g. surf style spring reverbs, or more grit for a delay.

I haven't fully committed to the rat hole of IR libraries yet though- maybe with more careful IR selection to match an imagined sound, the high/low cutoffs become less important.
 
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I like to do an EQ comparison test for the extreme highs and lows. I take a recording that has a guitar tone similar to what I'm after - in a similar style of music - and boost certain regions, like, say 10kHz. I listen for what it does to the guitar tone. Then I do the same thing with my guitar tone and adjust the lowpass filter until I have a similar response to the recording. Then I do the same with a low frequency or two.
This method has helped me as a reality check as I find that my ear can easily distinguish whether or not there is too much bass or treble, but I can't easily distinguish if the highs or lows are in the right area.

In my experience, 5kHz is pretty low, but I'm sure it depends on the IR being used and the slope of the lowpass filter.
 
it may be the speakers specs, but it does not mean there isn't sound past those specs.

for example, I own a stock Marshall 1960B and according to Celestion the G12T-75 is spec'd 80Hz - 5,000 Hz, with a resonance of 85Hz. Real world testing with a reference mic both on the grille cloth and room, show an actual Freq range from 45Hz all the way up to 16,000 Hz. I found the resonance of this particular 412 cab to start around 67Hz and drop out at 91Hz.

Based on this finding, I have decided to never use the cuts on the cab block and jsut leave it full range, This way I get the closest thing to a real amp tone on stage, and the sound engineer running the board has a full range to mix as required for the room and FoH PA.

I've done it this way for 3 years with no issues at all.

YMMV
 
Just a quick question from an original Ultra user....I run a PEQ after my cab block as I do not have a Cab Block internal cut parameter. If I wanted to apply this theory, which is what I'm doing with the PEQ....would I be putting that after the cab block or between the amp/cab block.

I would think the cab block would already have its EQ at the output, so maybe trimming it pre-cab block would make more sense?

Does anyone know where that EQ section is working within the cab block? Maybe I'll get a better result by moving my block.
 
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