When asked if Kemper Profiler uses Impulse Responses, which they claim they don't:

They do use IRs. They use 256 point IRs augmented with parametric EQ. This is easily demonstrated by examining the data structure of the profile and by measuring the device (or by using their IR converter which converts long IRs to 256 point IR plus EQ). What they say is "we use something more advanced" or something like that. By "more advanced" they mean they augment the IR with parametric EQ. However they must augment the IR with parametric EQ because the IR is too short to reproduce low frequencies accurately. The frequency resolution of an IR is proportional to its length: the longer the IR the better the resolution. To accurately reproduce a guitar cabinet requires at least 1000 points from my research. (Note: I'm using the term "parametric EQ" as a substitute for IIR filter since most people don't know what an IIR filter is.)

This technique has been around since the early days of modelers (I believe the Pod 2.0 was the first to do this). The impetus for this is that it uses much less processing power since the amount of processing power required is directly proportional to the length of the IR. A 256 point IR plus, for example, an 8-band EQ can be equivalent to a 512 point IR but uses less processing power. The downside is the phase response isn't the same but that is usually inaudible.

In their specific case the amplifier output frequency response and cabinet frequency response are combined into a single IR plus EQ since they aren't measured separately. See my MIMIC whitepaper for more information on frequency response, etc. You can make assumptions about the amplifier output frequency response in order to separate it from the cabinet response. In their case I believe they assume there is a 6 dB resonance at 125 Hz plus a 6 dB highshelf (incidentally this is the same power amp frequency response model that the Marshall JMP-1 used albeit using analog filters). For many amplifiers this is a reasonable approximation.

The Axe-Fx II IRs are 2048 sample (eight times the resolution) and don't require augmentation.

What about Two Notes CAB stuff ? It seems to be good stuff and has good reviews,

I'm wondering about maybe getting an 11 and the Two Notes CAB pedal

I can get both for under a grand !

Instead of the Kemper or Axe ?

Seems like I could get decent tones ?

Well, you have to look at it like this... not all things digital are equal.

For instance, lets talk computer processors, a good example are the older generation Pentium 4's. They would run at a clock speed of 4ghz, yet, numerically, less capable of resolving complex computations than a like generation 2.8ghz AMD Opteron cpu.

To the untrained mind, you see 4ghz and think "Well, has to be better than 2.8ghz!" but in reality... no, it's not.

Things like IR's; their "bit rate", samples, and respective algorithms create a scenario full of so many variables that to make an assessment from that alone to comparable quality would be a lark at best.

When the Axe FX III ships with 4096 "sample" IRs, everyone will claim the Axe FX II sounds too unrealistic to be believable. :D:D:D

For the Two Notes Cab -

Third-party IRs in .WAV or .AIF format
The TORPEDO C.A.B. is compatible with standard IRs in .WAV or .AIFF format. The remote will handle
any kind of resolution, frequency, length, and will follow the process to convert the file into the
TORPEDO format:
1. Normalizing to 0 dB
2. Troncation at 18,66 ms
3. Conversion to 24 bits/48 KHz
To upload a .WAV or AIFF file into your machine, place the file in your default Remote folder (or in a
folder you define in the TORPEDO Remote) and use the Memory Manager of the TORPEDO Remote.

I've just spent an hour and a half just using my guitars natural tone plugged into the Cab with only my maxon for a small boost and the power-amp sims - LOVELY cleans!!! wow.

Keep in mind, the 11R has ~3 ms of latency. The Torpedo Cab has about 3 ms of latency. Latency starts to become perceptible at about 6 ms. Add the two together (11R + TC) and your round trip latency is about 6 ms which is right at that threshold where the latency starts to become noticeable.

Now feed that setup through a typical class D FRFR which has it's own digital processing (or an IEM) and you add 2 more ms of latency. Now you're pushing 8 ms of round trip latency. Also, the distance you stand away from your monitor adds more latency. At that point, you may begin to feel a bit disconnected from your rig. The amp sims may feel like they're off in the distance.

Personally, I can deal with about 12 ms of latency just fine. I can adjust to it pretty quick. But, I find 20 ms of latency bothersome.

IIRC the Axe FX II has <1 ms of processing latency. I don't know about the Kemper but I'd guess it's between 2-3 ms.

I don't find any noticeable latency issues using the Eleven and TC. I run either into 11 > TC in fx or more recently - Guitar > TC > 11 fx loop send.

look into the new MIMIC technology in axe fw10

it's incredible.

I gave the kemper units a test drive at namm- i really wasn't impressed.

I wasn't trying to start any comparisons here, or say one was better than the other. I just thought it was an interested tidbit, that's all.

DUDE!!!
just noticed your profile pic please post or send me a link in hirez I want to see inside of the 11r and can't wait till my warranty runs out in november.... thanks!!!

@Jamin,

Don't want to sound like an ass, but google 'inside eleven rack' on images...plenty to see!