Cab sims

[Altitude]

Could someone explain to me how a cab sim is more than preset EQ settings?

Amp sims I get - there's a lot going on there with drive tendencies and gain approach in addition to EQ. But how, at the end of the day, does any cabinet do more than affect the sound frequency curve on the signal being sent to it as it reproduces?

Asking sincerely, not combatively.

 

[scuzzy]

Could someone explain to me how a cab sim is more than preset EQ settings?

Amp sims I get - there's a lot going on there with drive tendencies and gain approach in addition to EQ. But how, at the end of the day, does any cabinet do more than affect the sound frequency curve on the signal being sent to it as it reproduces?

Asking sincerely, not combatively.

they certainly are manipulating the eq, in an attempt to get the sound the same as you would hear through a cabinet. this may or may not be able to be precisely duplicated depending on the EQ pedal/gear you have on hand.

stolen from fractal forums...

"First, let's address terminology: both EQ and IRs are linear. There are many ways to define linearity. For purposes of this discussion, linearity can be explained best by saying that the response of a linear system does not change due to differing input signal levels.

The difference between an impulse response and a set of simple electrical (or virtual) filters is largely abstract. Any collection of filters will have its own impulse response, and one way of implementing that set of filters is via the same process that the Axe-Fx uses to implement cab sims, which is called convolution. In fact, all digital filtering processes involve some form of convolution.

With simple EQ-type filters, the total number of taps (points) required, and the associated processing burden, can be relatively small. This makes this type of filter easy to implement, but the price you pay is that the level of detail that can be introduced in the resulting frequency response is small. This makes it essentially impossible to successfully emulate the behavior of a guitar cab with simple EQ.

Using real-time convolution with an impulse response ("IR"), OTOH, has the possibility of duplicating all the response detail that your hearing is capable of recognizing. The price you pay for this is that, to achieve satisfactory results, the length of the IR must be sufficient. Adding more points creates a higher burden on the cpu. The 1024-point length of the Axe-Fx IRs is sufficient to capture the audible detail in the response of a guitar cab.

When you compare an IR-based cab sim to an EQ-based attempt to emulate the same cab, the IR - assuming it is long enough - will win every time. This is because much of the response of a guitar cab is due to multipath interference effects, which real-time convolution can duplicate and simple EQ cannot. Neither approach is "dynamic," however. Both processes are linear."

Fixed EQ vs IR | Fractal Audio Systems Forum

hope that helps answer the question. i may be missing the mark here. if so, apologies.

 

[ga_edwards]

I've been thinking about this since getting my Helix a few years ago. The only answer I can come up with is "it depends".

Sticking a mic in front of a guitar speaker is a technique nearly as old as the electric guitar itself. The guitar amp and speaker choice are as much a part of the instrument's tone as the guitar itself. As such, cab sims and IRs make absolute sense.

Us bassists (or at least many of us) however, are used to a variety of techniques to get our sound heard. DI box, DI from amp head, or a mic in front of a cabinet. Frequently it's a mixture of a couple or all three of these options. Not to mention, many legendary bass tones were recorded direct into the mixing console!

Devices like the Helix enable you to recreate all of these tonal and routing options. If you're used to a simple DI from an amp head, you probably don't need to worry about cab sims. But those who have spent many years with a mic in front of their cab will be more discerning.

Personally, I come from a combo / mini stack background and I'm used to either filling the room with my amp or plugging an XLR into the head to the PA for extra volume. As such, I prefer to use a simple eq block that tops and tails my signal with hpf/lpf. This shapes my humble frfr speaker into typical combo amp territory. It also replicates (and gives me more control) what a sound enginner would typically do with my traditional amp's DI signal.

One thing to remember. A cab sim or IR of an 8x10 for example, played though any speaker in a live environment is not truly representative of the real cab sitting behind you. It replicates the sound of particular microphone in front of a single speaker of a particular cab. It's not an "amp in the room" sound. Think of it more as "amp in the other room".

This is why I prefer the eq solution. It feels more like a real bass cab sitting behind me, rather than a recording of one.

 

[ga_edwards]

Some bassists like super hi fi sounds. I don’t, especially getting past 5k, and that’s whether I play clean or dirty. So my DI line has a cab sim on it.

Same here. Every preset in my Helix has an hpf that rolls off around 5-6khz. Even the synthy ones!

 

[jimfist]

One thing to remember. A cab sim or IR of an 8x10 for example, played though any speaker in a live environment is not truly representative of the real cab sitting behind you. It replicates the sound of particular microphone in front of a single speaker of a particular cab. It's not an "amp in the room" sound. Think of it more as "amp in the other room".

Yes. Picture yourself in the control room of a recording studio where an Ampeg B-15 is being close mic'd with an RE20 mic, with the intent of finding various sweet spots of mic placement that would fit the bass tone well in a mix. These mic'd cab locations are what are captured in the cab sim IR.

Taken further, there's no reason to stop with just one mic and any old mic preamp when capturing a cabinet IR. Ultimately, the digital IR can be of any signal that is run to the IR creation software. This could be multiple mics; boutique/vintage EQ or mixing desk EQ; tone enhancement from harmonic distortion via vintage compressors (note that neither the distortion itself or compression is captured, but only the impact it has on the shape of the EQ).

In essence, anyone with the gear and tech chops can create a cab IR that includes a small fortune worth of captured processing gear that you'd never want take out on a gig (mics, preamps, EQs, etc.). You could take a line out from your bass head and run it into the cab IR playback device and essentially have the tone you produced in the studio when creating the IR. Better yet, a feed taken from a load box between the amp (tube) head and speaker will further enhance since it will have the variable impedance interactions between the amp and speaker - part of the ever-elusive "feel" when using a tube head. Two-Notes Captor and C.A.B. M fall into this category.

 

[Altitude]

they certainly are manipulating the eq, in an attempt to get the sound the same as you would hear through a cabinet. this may or may not be able to be precisely duplicated depending on the EQ pedal/gear you have on hand.

stolen from fractal forums...

"First, let's address terminology: both EQ and IRs are linear. There are many ways to define linearity. For purposes of this discussion, linearity can be explained best by saying that the response of a linear system does not change due to differing input signal levels.

The difference between an impulse response and a set of simple electrical (or virtual) filters is largely abstract. Any collection of filters will have its own impulse response, and one way of implementing that set of filters is via the same process that the Axe-Fx uses to implement cab sims, which is called convolution. In fact, all digital filtering processes involve some form of convolution.

With simple EQ-type filters, the total number of taps (points) required, and the associated processing burden, can be relatively small. This makes this type of filter easy to implement, but the price you pay is that the level of detail that can be introduced in the resulting frequency response is small. This makes it essentially impossible to successfully emulate the behavior of a guitar cab with simple EQ.

Using real-time convolution with an impulse response ("IR"), OTOH, has the possibility of duplicating all the response detail that your hearing is capable of recognizing. The price you pay for this is that, to achieve satisfactory results, the length of the IR must be sufficient. Adding more points creates a higher burden on the cpu. The 1024-point length of the Axe-Fx IRs is sufficient to capture the audible detail in the response of a guitar cab.

When you compare an IR-based cab sim to an EQ-based attempt to emulate the same cab, the IR - assuming it is long enough - will win every time. This is because much of the response of a guitar cab is due to multipath interference effects, which real-time convolution can duplicate and simple EQ cannot. Neither approach is "dynamic," however. Both processes are linear."

Fixed EQ vs IR | Fractal Audio Systems Forum

hope that helps answer the question. i may be missing the mark here. if so, apologies.

Actually quite informative. Thanks.

 

[Texan]

I switched from a Genzler/Bergantino Rig to a Fractal FM3 about 6 months ago. I bought Celestion Pulse IR's, 410, 12" and 15" as well as a Bergantino IR and I was skeptical at first, but after a few gig's I love it. The key for live is IEM's and a good PA.

the Fractal software lets you adjust so many of the IR parameters that you can really go down a rabbit hole.

 

[jimfist]

I switched from a Genzler/Bergantino Rig to a Fractal FM3 about 6 months ago. I bought Celestion Pulse IR's, 410, 12" and 15" as well as a Bergantino IR and I was skeptical at first, but after a few gig's I love it. The key for live is IEM's and a good PA.

the Fractal software lets you adjust so many of the IR parameters that you can really go down a rabbit hole.

Impressive that the FM3 was able to replace your Genzler/Bergantino rig.
Care to share your effects/amp/cab chain inside the FM3 ( thanks)?
I'm curious as to how other bassists implement Fractal gear.
I'm on the waiting list for an FM9 but on the fence about whether to pull the trigger.

 

[Texan]

Impressive that the FM3 was able to replace your Genzler/Bergantino rig.
Care to share your effects/amp/cab chain inside the FM3 ( thanks)?
I'm curious as to how other bassists implement Fractal gear.
I'm on the waiting list for an FM9 but on the fence about whether to pull the trigger.

I was going to wait for the FM9, but went ahead with the FM3 and FC6 and a few stand in switches. I do a bit of guitar work too and I have no issues with the functionality of this setup.

As far as signal chain, I use the Bandcommander (Bandmaster model) for a clean, SWR type sound, the Mesa 400 model for something a bit more rockfish and the 59’ bassman model for a bit more present modern sound. IRs are either the Bergantino NXV322, Celestion IRs that I mentioned before or the Mesa 215 and 410x15 IRs. Some patches, compression at the beginning and end, Parametric and graphic eq’s, various drives. I really love the flexibility and ability to tweak.

if you want more specifics, PM me. Lots to type.

 

[jcburn]

Ever since switching to the Darkglass Alpha Omega Ultra I've been going down the cab sim/IR rabbit hole. Took a while to find some that sounded better than not having the cab sim on (the IR's that come with the pedal are dreadful) but now I love it!

Hey man - did any of the Redwirez cab IRs work for you?

 

[mmbongo]

Hey man - did any of the Redwirez cab IRs work for you?

I found a bunch I liked, mostly the DB115's. But right now I'm still using the Sunn IR from the Shift Line stuff. I appreciate it!

 

[jcburn]

I really dig the Sunn 215 IR as well.

No probs at all.