Firmware supplied IR's

[rtcook]

How can I tell which of these IR's are NF and which are FF? Only a couple seem to have that in the description.

Thanks,

Roger

 

[javajunkie]

The ones that say (JM) at the end are far field. The rest are near field.

 

[rtcook]

Thanks! Then there's only three available and none are 4x12's. Any suggestion on a good FF 4x12 cab? Currently using #41 Marshall 1960B V30. Want a cab like that to compare to my real cabs.

Thanks,

Roger

 

[Tone Seeker]

I suggest you look into what Ownhammer is putting together, which you can read about in this thread. . .

http://forum.fractalaudio.com/user-cabs-irs/47564-ownhammer-room-far-field-irs.html

Terry.

 

[barhrecords]

Thanks! Then there's only three available and none are 4x12's. Any suggestion on a good FF 4x12 cab? Currently using #41 Marshall 1960B V30. Want a cab like that to compare to my real cabs.

Thanks,

Roger

IIRC, the 2x12 G12-65 Far-Field (JM) factory IR was captured in such a way that it approximated a 4x12? There was a technique where a mirror reflection of the 2x12 resulted in a 4x12 type of sound.

Richard

 

[nikki-k]

Also, be aware of the effect multiple speakers in a cab will have upon a FF IR.

 

[Tone Seeker]

Also, be aware of the effect multiple speakers in a cab will have upon a FF IR.

Some comb filtering, correct?

Terry.

 

[nikki-k]

Some comb filtering, correct?Terry.

Yes.

For myself, it is a matter of reproducing the sound of my cabinet from a few feet away. Some people prefer the sound they get from a 4x12.. but often, they have not ever tried using a 1x12 cab. Usually, it is due to the 4x12 providing a compact, easily transportable *load* that can handle the *volume* they require in a live situation, and/or for studio use (such as cranking a Plexi with Greenbacks). Funny thing is, most of the cabs people think they have heard live or in a studio are not actually the cabs, but rather a single speaker (close mic).

Next time you get a chance to do full stage volume with a 4x12, walk back and forth, and change the height of your head. Now imagine trying to place a mic to capture what you hear at your favorite spot. If you then consider everything that is contributing to that sound, and think of it as an equation... you can begin to remove certain things.

If you were to replace the 4x12 with an FRFR cab/amp, you would have the same room.. remove it from the equation. If you are in the room, and you are in the same spot, and obviously using the same ears.. you can also remove yourself (the spot you are standing in, your ears, etc) from that equation. You can use the same amp/head, so remove that too. And now you are left with.. the speakers and the cab. Imagine a hypothetical "non-coloring loadbox and IR box" that could replace the 4x12, and the FRFR rig hooked to it (thus allowing you to retain the tone of the amp/head).The trick is to capture an IR of the speakers and cab as pristinely and neutrally as possible so that if you were blindfolded and unaware of the cabs being swapped (4x12 vs FRFR + IR), you would not be able to discern any difference between the two. Oh- by removing the room from the equation? That means you need to find a way to remove it when capturing the IR as well. Otherwise.. you would need a larger IR, and you would need to have a "roomless" environment to then play the rig in in order to experience the sound.. of the cab in that room.

Reread that, and take the time to seriously consider it all. Technically, it should be possible (I believe Jay Mitchell has stated that; he also states that at ~2m, a 1024 pt IR is capable of doing so.. PLEASE correct me if I am wrong!). However, more than one speaker in the cabinet of origin creates a bit of a quandary, as you are now adding an additional variable: comb filtering. IMO, and all of this is based upon cursory knowledge (BTW), that variable is not worth the effort. To find a spot where the comb filtering is "sweetest," and also allow for things such as ground plane effect? It is no longer "reproduce my rig in a FRFR scenario," but rather, "provide me with a NEW speaker and/or cabinet color, possibly including microphone and/or mic preamp coloration, that I can substitute for the one I already like." Personally, I want.. NEED.. the former; I want MY cabs in an IR form that can "fool me" if blindfolded. Or, I would even settle for the latter; unfortunately, I have yet to experience someone else's IRs that "do it" for me. I have gotten decent results with my own IRs (captured using my inferior technique, using my awful room, using 2x12 cabs.. and using a convolution method plugin in my DAWquencer post recording).

Let us say that you have the ability to hire someone that can actually produce an IR of that quality. You still need a *proper* convolution *method* for optimum results (read as: performs as it technically should according to theory). I am NOT stating that the Axe is not capable of this, nor am I stating that other available *methods* are inferior to this "theoretical perfect model." Personally, in keeping with the tenets of critical thinking, I cannot be satisfied with a simple, "Well, all these coders must know what they are doing.. everything sounds great!" Dig into analogue/digital converters; the perfect theoretical converter does not exist in real life.. everything we are afforded today are compromises. But, understanding the science and math behind it.. or as much as is possible... provides for more informed decisions. For some, this is so far from necessary that it seems silly to even consider (and those of us that do may seem even sillier ); for others, life can almost seem to halt until at least a cursory, informed understanding is attained. Luckily, most of you likely exist in the nice, big, comfy area in between those two extremes

 

[Scott Peterson]

Nikki - paragraph breaks... please!

 

[nikki-k]

Nikki - paragraph breaks... please!

Oh, boogers on toast. I had breaks, but the forum software removed them following a preview. &*^&$%#b *#^%# phpbb irks me sometimes... fixing...

 

[AlbertA]

Yes.

Reread that, and take the time to seriously consider it all. Technically, it should be possible (I believe Jay Mitchell has stated that; he also states that at ~2m, a 1024 pt IR is capable of doing so.. PLEASE correct me if I am wrong!).

Yes normally when you play through the cab you don't have your ear shoved at the grillcloth. You are hearing the far field of the cab. One way to capture this is to use the ground plane measurement technique. It's the easiest to capture a reflection free impulse response (in the window of interest). By capturing at 2m, you cancel the SPL increase from the coherent addition of the ground reflection.

However, more than one speaker in the cabinet of origin creates a bit of a quandary, as you are now adding an additional variable: comb filtering. IMO, and all of this is based upon cursory knowledge (BTW), that variable is not worth the effort. To find a spot where the comb filtering is "sweetest," and also allow for things such as ground plane effect? It is no longer "reproduce my rig in a FRFR scenario," but rather, "provide me with a NEW speaker and/or cabinet color, possibly including microphone and/or mic preamp coloration, that I can substitute for the one I already like."

It's not an additional variable. At your normal listening position you already hearing the effect of the 4x2 speaker array (how close do you sit to your cab?). You may be confusing it with directivity in which case yes select an angle of capture that best represents you usual "sweet spot".

Personally, I want.. NEED.. the former;

See above

I want MY cabs in an IR form that can "fool me" if blindfolded. Or, I would even settle for the latter; unfortunately, I have yet to experience someone else's IRs that "do it" for me. I have gotten decent results with my own IRs (captured using my inferior technique, using my awful room, using 2x12 cabs.. and using a convolution method plugin in my DAWquencer post recording).

Don't forget the FRFR system used for reproduction as well

Let us say that you have the ability to hire someone that can actually produce an IR of that quality. You still need a *proper* convolution *method* for optimum results (read as: performs as it technically should according to theory). I am NOT stating that the Axe is not capable of this, nor am I stating that other available *methods* are inferior to this "theoretical perfect model."

Brute force convolution is trivially simple to implement. Efficient convolution less so. However, it's very easy to check for correct operation.

I'm kinda lost on the theoretical perfect model thing though, what was the point there?

 

[nikki-k]

Having a rough day, please excuse the lack of proper quoting...

Reread that, and take the time to seriously consider it all. Technically, it should be possible (I believe Jay Mitchell has stated that; he also states that at ~2m, a 1024 pt IR is capable of doing so.. PLEASE correct me if I am wrong!).

Yes normally when you play through the cab you don't have your ear shoved at the grillcloth. You are hearing the far field of the cab. One way to capture this is to use the ground plane measurement technique. It's the easiest to capture a reflection free impulse response (in the window of interest). By capturing at 2m, you cancel the SPL increase from the coherent addition of the ground reflection.

This means that, effectively, no matter the cab in question, 2m is the "magic distance," yes?

However, more than one speaker in the cabinet of origin creates a bit of a quandary, as you are now adding an additional variable: comb filtering. IMO, and all of this is based upon cursory knowledge (BTW), that variable is not worth the effort. To find a spot where the comb filtering is "sweetest," and also allow for things such as ground plane effect? It is no longer "reproduce my rig in a FRFR scenario," but rather, "provide me with a NEW speaker and/or cabinet color, possibly including microphone and/or mic preamp coloration, that I can substitute for the one I already like."

It's not an additional variable. At your normal listening position you already hearing the effect of the 4x2 speaker array (how close do you sit to your cab?). You may be confusing it with directivity in which case yes select an angle of capture that best represents you usual "sweet spot".

The comb filter effect with a 4x12 is equal no matter how one faces the cabinet, as well as from any distance (on all planes)? If so, I definitely confused directivity with that effect. I was un der the impression that the filtering effect would change depending on where and angle.

Personally, I want.. NEED.. the former

See above

I am unsure of what the "see above" has to do with my quote. I have had a fumble-y day today, and typically have communication issues, so it is not "on you," but me trying to figure where I went wrong...What my "need the former" was referring to was this:

"reproduce my rig in a FRFR scenario,"

Reason being, I want to be able to have the experience of playing through my cabs when using my FRFR system (studio monitors). Currently, it is drastically different, so much so that not using one of my cab is not an option. And that is the primary reason for my obsession with learning all I am able about IR use and capture. Unfortunately, the more I learn, the more I lean toward "not going to happen" for capturing my cabs *properly*.--------phpbb will not let me line break here-------I am always looking for new gear to make new sounds. This was one reason for buying the Axe-Fx II. Unfortunately for me, I have not found any stock IRs (or combinations) that "do it" for me. I am not a fan of playing while listening to a close mic'd cab. Never have been. FF IRs have not thus far sounded/felt like being in my room with a cab either. This is one reason I want some "perfect" IRs of my cabs: so I can find out if there is some failing with IRs, a psychological poison of some sort, or something I have not discovered/thought of yet. If an IR can theoretically provide for a nearly identical experience, then I want to experience it

I want MY cabs in an IR form that can "fool me" if blindfolded. Or, I would even settle for the latter; unfortunately, I have yet to experience someone else's IRs that "do it" for me. I have gotten decent results with my own IRs (captured using my inferior technique, using my awful room, using 2x12 cabs.. and using a convolution method plugin in my DAWquencer post recording).

Don't forget the FRFR system used for reproduction as well

I already have a high quality FRFR system: Blue Sky System One 5.1 system. It is capturing the IRs that I am having trouble with (knowledge, technique, and the room). And being unable to afford to grab the 1x12 boxes I want for the captures. I figured if I had the cabs, I could hit a local studio. But, without the knowledge and technique...

Let us say that you have the ability to hire someone that can actually produce an IR of that quality. You still need a *proper* convolution *method* for optimum results (read as: performs as it technically should according to theory). I am NOT stating that the Axe is not capable of this, nor am I stating that other available *methods* are inferior to this "theoretical perfect model."

Brute force convolution is trivially simple to implement. Efficient convolution less so. However, it's very easy to check for correct operation.I'm kinda lost on the theoretical perfect model thing though, what was the point there?

Once again, knowledge. With converters, consider the filter; better equals expensive. Without a perfect filter, compromise must happen. Where to compromise? The science remains true, but implementation ends in compromise. With IRs, where are the compromises between theoretical "perfect" capture and theoretical "perfect" implementation (convolve)? As you stated: Brute force is easy, efficient less so. Is "best result" convolution possible in a real-time form (plug-in, stand-alone unit) with the current dsp power we have available? If yes, how much is required, and for what processes? Most times, in the past at least (unsure about these days, lol), when coding up something for real-time operation, some compromise would need consideration. For lowest latency operation for a process, some sacrifice would need to occur. Are we at a point when no compromise is needed for convolution in real-time? Does the Axe-Fx II have any compromises with its convolution method?

 

[nikki-k]

phpbb is really giving me a run today Sorry if I did nto express myself properly/well enough. I am quite honestly and enthusiastically curious about this.

 

[barhrecords]

@AlbertA,

I thought at 2m you get the coherent addition from the ground plane reflection and a 6db increase?

I thought at 1m the coherent reflection was *not* additive?

Richard

 

[LMO]

By capturing at 2m, you cancel the SPL increase from the coherent addition of the ground reflection.

I don't understand this comment; SPL is proportional to the distance, so to cancel the increase you'd have to be at twice the distance. Assuming you are comparing to a NF measurement, which I take as generally being in the range of one foot or less, you're still going to see a much lower SPL at two meters. OTOH, I don't see why it is an issue, since the levels usually are (or can be) normalized during post-processing.

I thought at 2m you get the coherent addition from the ground plane reflection and a 6db increase?
I thought at 1m the coherent reflection was *not* additive?

You get coherent addition at any boundary, regardless of the distance from the source.

 

[barhrecords]

I don't understand this comment; SPL is proportional to the distance, so to cancel the increase you'd have to be at twice the distance. Assuming you are comparing to a NF measurement, which I take as generally being in the range of one foot or less, you're still going to see a much lower SPL at two meters. OTOH, I don't see why it is an issue, since the levels usually are (or can be) normalized during post-processing.


You get coherent addition at any boundary, regardless of the distance from the source.

Yes but if the source, the microphone and the boundary form an equilateral triangle, then the reflection and the direct sound are in phase. Otherwise there would some some addition and some subtraction due to phase differences between the reflection and direct wave.

Richard

 

[LMO]

Yes but if the source, the microphone and the boundary form an equilateral triangle, then the reflection and the direct sound are in phase. Otherwise there would some some addition and some subtraction due to phase differences between the reflection and direct wave.

Richard

The mic is at the boundary, so the direct and reflected wave are in phase.

Edit: if the source, mic, and boundary form an equilateral triangle, you have direct sound traveling x meters, and reflected sound travelling 2x meters (two sides of the triangle). There will definitely be phase differences in that situation.

 

[barhrecords]

The mic is at the boundary, so the direct and reflected wave are in phase.

Sorry for the confusion, in the discussion about Jay's IR mimicing a 4x12, I believe the IR was captured without the microphone being in the ground plane.

 

[AlbertA]

@AlbertA,

I thought at 2m you get the coherent addition from the ground plane reflection and a 6db increase?

I thought at 1m the coherent reflection was *not* additive?

Richard

Sorry I forgot to add "when compared to an-echoic measurement at 1m"; so what I meant was:

"By capturing at 2m, you compensate for the 6dB increase in SPL from the coherent addition of the ground reflection when compared to an anechoic measurement of the same cab at 1m."

 

[AlbertA]

I don't understand this comment; SPL is proportional to the distance, so to cancel the increase you'd have to be at twice the distance. Assuming you are comparing to a NF measurement, which I take as generally being in the range of one foot or less, you're still going to see a much lower SPL at two meters. OTOH, I don't see why it is an issue, since the levels usually are (or can be) normalized during post-processing.


You get coherent addition at any boundary, regardless of the distance from the source.

See above. Yes coherent addition happens - my point was to explain the 2m figure.