Why is it necessary to apply high/lo pass filters to cabs?

[j20056]

Is the design of the cab modeling technology such that it inherently does not capture the frequency response of a speaker cab? It seems like a requirement to apply at least a low pass to cut the highs to get a more realistic cab sound. Assuming that is the case, one would expect that a given cab loaded with a given speaker would have a reasonably uniform frequency response curve. In that basis, there should be a default or base EQ curve automatically provided that should match a cab in a normal micing configuration.
Trying to understand if it is 100% required to do this EQ work on a cab by design or by necessity, either way?

 

[FractalAudio]

It is not required or necessary.

However, high/low pass filters are typically applied to close mic'd guitar tracks during mixing to help the guitar "sit in the mix".

You should do some reading on close micing vs. "in the room". This topic has been beaten to death since the early days of modelers.

 

[Paulzx]

Is the design of the cab modeling technology such that it inherently does not capture the frequency response of a speaker cab? It seems like a requirement to apply at least a low pass to cut the highs to get a more realistic cab sound. Assuming that is the case, one would expect that a given cab loaded with a given speaker would have a reasonably uniform frequency response curve. In that basis, there should be a default or base EQ curve automatically provided that should match a cab in a normal micing configuration.
Trying to understand if it is 100% required to do this EQ work on a cab by design or by necessity, either way?

I don't know the outright answer to that question except to say that in my experience, depending on the amp model, it sometimes pays to leave hi and low cut off altogether because the amp tone is more alive. But some amps do sound a lot better with the cuts, particularly if they are fizzy.

There may be an answer to the above but I don't think there's a definitive solution because you can only use your own judgement with these cuts in each case or each preset

 

[j20056]

Thanks. I guess my question was more about the theory of cab modeling. I understand nuances and preferences and micing method impact. But fundamentally, does cab modeling technology capture the inherently limited frequency response of a 8-12 inch speaker? In other words if I apply no hi:low filters should I be close to home versus listening to the same real amp and cab?

 

[Randalljax]

Thanks. I guess my question was more about the theory of cab modeling. I understand nuances and preferences and micing method impact. But fundamentally, does cab modeling technology capture the inherently limited frequency response of a 8-12 inch speaker? In other words if I apply no hi:low filters should I be close to home versus listening to the same real amp and cab?

When you close mic a cabinet the microphone is going to pick up much more high end information than you would be used to standing in a room with a cab , we never put our ears directly on the speaker so by nature what our ears hear is a much narrower band of frequency than a mic would
Due to this many players or artists will try to get the cab IR as close to the listening experience they are used to
To do this they are cutting off the frequencies that the player standing 2 ft away from a cab would not hear

There are different schools of thought, Justin York for instance does no high cuts
If he has fizz he just turns down the treble or presence
But his theory is there is still energy and value in the higher freq getting through and it sounds more dull by removing them

Some bands like Aerosmith I think I read use hi cuts down to 4500 to 5000. Likely because they are more comfortable with that response

 

[Chuck P]

Thanks. I guess my question was more about the theory of cab modeling. I understand nuances and preferences and micing method impact. But fundamentally, does cab modeling technology capture the inherently limited frequency response of a 8-12 inch speaker? In other words if I apply no hi:low filters should I be close to home versus listening to the same real amp and cab?

In short: Yes. With the EQs off, you get what that cab actually sounds like through that mic/preamp/etc.

 

[sprint]

In other words if I apply no hi:low filters should I be close to home versus listening to the same cab?

If u mean listening to the same cab directly in a room, then No afaik, because an IR does not solely represent a direct cab listening experience, rather, it is a given mic's interpretation of that cab (sitting in a different room from where u are) at a certain mic distance / orientation and fed thru a given micpre which, collectively, is different than listening to that cab directly (this being the heavily beaten part of the subject over many years as mentioned above)..

 

[stephanfm3]

seems to need some more beating

 

[empinchen]

In other words if I apply no hi:low filters should I be close to home versus listening to the same real amp and cab?

Not close to home but exactly at home. Assuming you are listening to the real amp and cab from a control room where you're sitting next to the engineer.

 

[aziz]

I never use high or low cuts. The IR sounds the same that the mic hears in front of the cabinet. Change the IR if its too bright.

 

[Aivoryuk]

the Kirchhoff EQ - https://www.threebodytech.com/en/products/kirchhoffeq - has a continuous variable for its HP and LP filters. Which means in stead of using 6db,12db slopes you can set a really gentle slope at a lower frequency which can tame some harshness without dulling the top end.

Would like to see that implemented into the Fractal.

 

[Shredology]

Modeling technology is making us have to think like recording engineers. I think as guitar players we plug into an amp and a cab and we either like the sound or we don't. Back in the day that meant selling an amp or cab that didn't sound great and buying something else.

With Fractal, we have the ability to make any amp and cab IR sound practically any way we want. That's what people seem to be doing with all this EQ'ing

So two options:
1.) tweak the shit out of an amp and cab IR until it sounds good to you
2.) try different amp and cab combinations until you find one that sounds great at default settings

tomato/tomatto

 

[randocaster]

Thanks. I guess my question was more about the theory of cab modeling. I understand nuances and preferences and micing method impact. But fundamentally, does cab modeling technology capture the inherently limited frequency response of a 8-12 inch speaker? In other words if I apply no hi:low filters should I be close to home versus listening to the same real amp and cab?

Using microphone captured IR's is comparable to sitting in the control room listening to the studio monitors as you record. Studio monitors or PA speakers will not give you the experience of sitting in front of a guitar cab. Whether it's a mic'd cab at a gig, or a recording situation, EQ will likely be applied to make your carefully crafted tone fit in the mix. One place you can do this is in the cab block with high and low cuts.

 

[j20056]

Thanks all.
My context was slightly more on the engineering side because my use case as a brand new III owner is a MarkV:25 with a 1x12 Mesa cab in the control room which is my sound room basically and is small. I am only focused on playing right now which eliminates recording subjectivity if sitting in the mix or what sounds ”good”.
I want a W/D/W setup with the III as the FX unit in 4CM mode (center dry is MkV and stereo wet is the III through Genelec monitors). I am not micing the MkV so I need to model it in order to feed signal to the wet processing. My approach is to either use the MkV preamp form 4CM into a AxeFX cab, or model the MkV altogether. This thread was in context of the latter.
As a result my first step was to try and replicate the amp+cab in the room as I directly hear it from 3 feet center with my ears.
Instead of more theory and subjectivity, I will try no EQ.
As an aside; anyone knows which fractal can is most likely to replicate a Mesa 1x12? So far the closest I found is the Mesa 4x12

 

[Parkinthepark]

Thanks. I guess my question was more about the theory of cab modeling. I understand nuances and preferences and micing method impact. But fundamentally, does cab modeling technology capture the inherently limited frequency response of a 8-12 inch speaker? In other words if I apply no hi:low filters should I be close to home versus listening to the same real amp and cab?

The cab modeling technology does capture the inherent frequency response of the speaker, along with any resonance effects of the cabinet itself.

It also captures the inherent frequency response of the microphone used to capture the speaker, and whatever preamp was used between the mic and the capture hardware.

However, what the microphone detects at the speaker grill is not necessarily what your ears detect standing in front of the cabinet, and might not be ideal for your performance or listening environment.

The hi/lo cut controls are provided for convenience to further tweak that close-mic'd sound for whatever application you need.

 

[sprint]

tomato/tomatto

not really: "sounds good / great" is a completely different concept than sounding true to a specific reference (speaker, mic, pre...). If all one wants is "good", then by all means, spin the dials till happy (tho one may want to bone up a little on what those dials do and how they work in order to have a better chance at "good")

an IR is the result of a recording process and is not the direct sound of a cab in a room - it is what it is despite any blissful wishes we might have to ignore that sometimes annoying recording process.

 

[IronSean]

My pet theory is that you don't.

Because it's useful when mixing and mastering for a recording where you want everything loud but not clipping, people learned to do it to guitars after an IR. Now for live they're emulating the same workflow.

But honstly, I think a lot of people just hear one frequency in the upper mids or highs they don't like, and go straight to the high-cut/low-pass meat cleaver and chop until they get rid of it (and everything else in the process) out of habit.

I think a lot of people could apply a PEQ to a couple problem frequencies and be even happier.

 

[peteri]

Since Mr York Audio opined on the topic, I’ve removed all cuts on the cab block.

Much happier with the result

 

[laxu]

As a result my first step was to try and replicate the amp+cab in the room as I directly hear it from 3 feet center with my ears.
Instead of more theory and subjectivity, I will try no EQ.
As an aside; anyone knows which fractal can is most likely to replicate a Mesa 1x12? So far the closest I found is the Mesa 4x12

You will have a lot of problems with this because the sound you hear is the sound bouncing around in the room, and heavily high cut by simply your ears being much higher than where a close mic would be. The easiest way to simulate "cab in the room" is just adding more high cut, but it will still miss all those things that you hear from the sound reflecting from the walls etc.

I would approach this differently. Forget trying to match the amp sound in the room, and instead try to find a setup that complements the dry sound with fx when you play both at the same time.

 

[Bobbyoso]

So I am a bit confused by this as well, because while a given amp thru a specific speaker cab may attenuate highs and lows IRL, I am not sure that additionally running it through delays, reverbs, "enhancers", and of course the virtual mics used to create speaker sims, etc., means that you still can cut below 150 hz and above 5-7khz (for example), and not lose acoustic/musical information and response.

Put another way, almost all really good sound processing, digital or analog, strives for as close to +/- 0 db from 20-20k. How does that affect what frequencies the "processed" amp patch needs to produce? I realize that such equipment is not solely designed for electric guitar processing--but does the additional processing change the low/hi cut "equation", if you are building patches that have this processing, vs. an "amp/cab only" patch?

Paraphrasing, do you lose musical info by cutting a fully-processed patch vs. an amp and cab patch? A bit difficult to frame it, but I guess the real question is--does dropping an LA-2 sim with a Bricasti reverb into an amp/cab patch (for example) ADD frequencies above/below your lo and hi "cuts", which necessitate altering or deleting those cuts?