Cab Sim vs. Room Reverb - What's the Difference?

[AlbertA]

Re: Red Wirez "Tone Recipe Formula" Sharing Thread

The problem with my room reverb has mainly been that it was too dull, or not bright or "lively" enough. So I put the reverb on the side, set the mix to 100%, and ran it through an EQ of its own to the output. Now my "room" sounds a lot more convincing.

Stephen Cole

You should also try increasing reverb density if you haven't already. I asked Cliff for this feature a while back to try to reduce metallicness in small room reverbs.

 

[sampleaccurate]

My view is that convolution reverb isn't always so necessary. The early reflections can be done with a reasonably short convolution. After some point the density increases and the impulse response is basically exponentially decaying noise with different EQ and different decay rates for different frequency bands,

One scheme for constructing dedicated room reverb for use in "auralizations" in acoustics prediction software involves exactly this method: early reflections are modeled by a ray-tracing algorithm and become part of an IR that is convolved with the signal. The tail is constructed statistically and spliced in. The process is generally not accomplished in real time, but that is not consequential for this use, which invariably involves recorded program material.

So basically, there's no point in wasting all that computational power on a 20 second impulse response when a recursive filter can behave the same perceptually at a much lower computational cost.

Agreed. Even with this hybird approach, the cpu power required is high enough that, at present, it is unlikely that it could be implemented in a MFX unit like the Axe-Fx. Given that Cliff had to dig to find room and cpu power for the second half of the present 1024-point speaker IR and that even an early-reflection IR will need to be on the order of 48k points, a future generation platform will need a lot more horspeower to implement this. I realize it's possible, but my money says it's still a few years down the road.

I don't claim to understand exactly why long reverbs don't require IRs and are easy to create with relatively CPU friendly algorithms, but I can say that in my experience creating long reverb that sounds great is generally easy and there are several VST plugins with low CPU drain that I use that sound fantastic, and many hardware devices that exist that do a great job.

It's ALWAYS been the short, early reflection part of the reverb that sounded either metallic or grainy, take your choice. My recording specialty (if I have one) is recording drums. That's my main instrument and that's what I have the most experience recording. That's probably one reason I tend to see early reflections as being "part of the sound itself" rather than the direct and the reverb. I'm sure you'll agree (or then again not so sure :shock: ) that for drums the room "reverb" or whatever you want to call it is extremely important. Dry drums, or dry drums with only long reverb sound dead and lifeless IMO and most people would agree. Over the years I've searched and searched for something that would make my drums sound like they were recorded in a good drum room. Finally with the introduction of convolution reverb my prayers were answered. I can now almost literally put my drums in the worlds finest, carefully tuned drum rooms, and the sound is better than it's ever been.

I consider convolution reverb indispensable for recording drums if you have no decent room. I record in a padded acoustically dead room and add the room sound with an IR convolution later. Maybe there's a hardware device that can do it as well using a mathematical algoritm, but I doubt I'd be able to afford it for a very long time. It also seems easier to preview various drum room IRs to find good sounds rather than trying to program them from scratch.

Yes, my computers are quad cores. I can run an amazing number of effects with a measured (not calculated) latency of just under 10ms (under 6ms if I reduce the number of effects).

I'm also amazed at the latency (or lack of latency) of the AXE. I'm used to the 10ms round trip of my computers.

I probably also prefer a more "ambient" or "roomy" sound for my guitar than most people which is why I guess I place a lot of importance on that part of the sound and have always been bothered by the shortcomings of hardware reverb units, at least the ones I could afford to buy. I can live a few more years with my 2 space rack computer to host IR plugins for my drums, and I mix my home recordings on a DAW capable of hosting any VST convolution plugin, so I guess I can't complain.

Stephen Cole

 

[drosei]

Re: Red Wirez "Tone Recipe Formula" Sharing Thread

Not on a real-time hardware-based processor. No such animal exists.

So what's this then?

SONY DRE-S777

http://www.testequipmentconnection.com/ ... 0SPECS.PDF

Mind you, this unit was made in 1999.

My opinion:

I agree with Jay that a cab sim should capture the anechoic response. Why?

Playing Live:

you have the acoustic space you are playing in to provide the ER and more importantly

because our ears do not listen like a reference microphone or 2 of them .

It is the DSP in our brain connected to our ears that makes the difference which provides among other things a perceptual 15-20dB supression of ER and noise .

This has to do with famous coctail party affect where the brain can pick up what the beautifull girl is saying and disgard what the boring jerk next to her is saying although the are both talking at the same level and are equidistant.

Try that listening through a reference mic and headphones. You will not be able to understand what either of the two are saying and it will sound more wet than in real life

For the same, but not so obvious reasons, bundling a long IR with ER to your live sound cab IR is, IMHO, just dirt.


Recording:

A long IR is like recording with reverb. Why would you want to do that and not add IR through a plugin later?

As the mix builds up you'll probably want to adjust it anyway.

And again translating a sense of space and organic liveness through stereo playback takes much more than the right IR.

It is IMHO what separates the great mixers from the not so great.

 

[sampleaccurate]

Re: Red Wirez "Tone Recipe Formula" Sharing Thread

Not on a real-time hardware-based processor. No such animal exists.

So what's this then?

SONY DRE-S777

http://www.testequipmentconnection.com/ ... 0SPECS.PDF

Mind you, this unit was made in 1999.

My opinion:

I agree with Jay that a cab sim should capture the anechoic response. Why?

Playing Live:

you have the acoustic space you are playing in to provide the ER and more importantly

because our ears do not listen like a reference microphone or 2 of them .

It is the DSP in our brain connected to our ears that makes the difference which provides among other things a perceptual 15-20dB supression of ER and noise .

This has to do with famous coctail party affect where the brain can pick up what the beautifull girl is saying and disgard what the boring jerk next to her is saying although the are both talking at the same level and are equidistant.

Try that listening through a reference mic and headphones. You will not be able to understand what either of the two are saying and it will sound more wet than in real life

For the same, but not so obvious reasons, bundling a long IR with ER to your live sound cab IR is, IMHO, just dirt.


Recording:

A long IR is like recording with reverb. Why would you want to do that and not add IR through a plugin later?

As the mix builds up you'll probably want to adjust it anyway.

And again translating a sense of space and organic liveness through stereo playback takes much more than the right IR.

It is IMHO what separates the great mixers from the not so great.

I agree.

It makes the most sense to break the signal chain down into as many components as possible (within reason) in order to provide the most flexibility in creating tones. What I would ideally like to see are two IR hosts, one short for cab EQ, and one long for reverb. If you didn't want to use it you wouldn't have to. But I would agree that they should be kept separate. I think everybody pretty much subscribes to this approach.

Psychoacoustics is a fascinating subject. It's amazing how many perceptual cues your ears provide to your brain and what the brain can do with that information. It also takes skill to create great mixes, and an good IR won't get you far without the rest of the signal chain.

Stephen Cole

 

[sampleaccurate]

So what did the Sony unit cost? 24/96 in 1999? Now it's a $500 computer and a lot more IRs to choose from.

 

[drosei]

So what did the Sony unit cost? 24/96 in 1999? Now it's a $500 computer and a lot more IRs to choose from.

12.000$. That is 12.000 99's $ not 09' $ :lol:

 

[Stratoblaster]

To more closely align our sampling techniques with the goals of live players, we are in the process of doing far-field samples in a quiet outdoor space using an Earthworks TC30 reference mic, a clean Earthworks mic pre, and ground planing techniques to eliminate reflections. Based on what I've heard so far, they can stand on their own, but I think they will be most useful with a few close mic'ed IRs blended for a little push in one direction or another.

http://www.redwirez.com/ir/MesaRectifierV30s-TC30.zip

Thanks for the preview RW, I'm going to try out the IR's in the .zip this weekend hopefully.

Do you have an ETA of when the complete far field IR's will be available?

 

[mik]

To more closely align our sampling techniques with the goals of live players, we are in the process of doing far-field samples in a quiet outdoor space using an Earthworks TC30 reference mic, a clean Earthworks mic pre, and ground planing techniques to eliminate reflections. Based on what I've heard so far, they can stand on their own, but I think they will be most useful with a few close mic'ed IRs blended for a little push in one direction or another.

http://www.redwirez.com/ir/MesaRectifierV30s-TC30.zip

Mike - Thank you very much for sharing these. They sound excellent on my system and actually sound close to my Mesa 4x12 as a matter of fact. From now on they are my go-to cabs that I choose,

Mik.

 

[onemoreguitar]

I was just wondering if that redwirez FF IR demo was still around? I've been looking at the redwirez for a while, but was waiting for some FF IR's done with a reference mic. Very keen to give it a go. I tried downloading it and it said the file no longer exists. Have all the cabs been redone with the Earthworks?