Help With Engineering My Own IRs

M

mattpeyton

New member
Folks

I've spent a night trying to make GREAT IRs of my cabinets. Overall - I've failed in 'cloning' my sound - going A/B between actual and IR version... not even really close. What am I missing? Is what I'm doing even possible?

Cabinet is oval back pine diagonal 2x12 with Eminence Wizards. I'm miking with a Royer 121 at 2 inches out, 1 inch left off center cap. Royer directly to API and into Apollo. I'm sending the 'wave' out of Apollo to a 500 watt bridged Behringer amp - and starting at about -10 db. I've tried hotter signals, lower signal. Test at -10 gives me peak of about -5. Hotter than that and I get alot of grit on top. Lower than that and it makes no difference.

When comparing the IR transfered to the Torpedo C.A.B. against the real thing - it's not even very close... there's a ton more 'air' and etc in the real thing - and the bottom is very different. The air part is sort of obvious - but I figured it would be reasonably close (closer than this)....

I've also tried sending the signal through the EFX return of a Marshall 100 (just for fun). Worse...

What am I missing.... ???
 
it would be good to post a clip of your cab using the royer and your preamp signal chain vs the same set up with your amp properly loaded and through the cab using the IR you created for comparison.
 
The IR will only give you the linear aspects of your sound, i.e. the freq response, and it will NOT give you any non-linear aspects, i.e. room tone (the IR is short at around 20ms + or -?), or any speaker generated compression/distortion etc.

It's always important to add some room tone to your chain with the IR, and the T_CAB has a nice room sim/reverb built in just for this purpose (or use a stereo room sim in your DAW etc).

If your sound is thin it's possible you're having standing wave/phase issues in your recording environment (especially with a ribbon!), so try baffling behind the mic to start.
 
Gents I will post clips in short order. The microphones are housed beautifully in a booth with soft "baffle walls" in front of them made by Clearsonic. The cabinets are on an isolated floor.. There are no early reflections or phase issues -I've been engineering for about 30 years. I have also created IR files from a set of Senn 906 - same issue. Overall a general lack of "balls". There is a certain harmonic complexity within the impulse responses-but they lack the power and punch of the real deal. I was wondering if I was doing something dramatically wrong. As a sidenote-monitoring open A and D chords for an hour or two at 80-85 DB kicked up my tinnitus-so it's unlikely I will be attempting much more than playing through this device for a day or two!
 
Just a follow up. Dropping the highs down on the built in EQ helped a little to 'equalize' the two signals - and the IRs I made aren't necessarily BAD - they sit in the track really well, in fact, and allow me to play sub 80 DB (since I don't have to monitor over the 'booth leak')... just different than the originals. Any IR making experts out there want to weigh in? Do you 'bake in' a degree of EQ to compensate for the limitations of the technology?
 
How big is the booth, and how high is it's ceiling?

Do note that ribbon mic's have figure-8 polar response, so you need to be equally concerned with what's behind the mic as well as what's in front of it.

Only the overall freq response of the source is captured by the short IR, nothing else (not sure what you're referring to with regards to "power and punch"?).

mattpeyton":1bz0e83p said:
Gents I will post clips in short order. The microphones are housed beautifully in a booth with soft "baffle walls" in front of them made by Clearsonic. The cabinets are on an isolated floor.. There are no early reflections or phase issues -I've been engineering for about 30 years. I have also created IR files from a set of Senn 906 - same issue. Overall a general lack of "balls". There is a certain harmonic complexity within the impulse responses-but they lack the power and punch of the real deal. I was wondering if I was doing something dramatically wrong. As a sidenote-monitoring open A and D chords for an hour or two at 80-85 DB kicked up my tinnitus-so it's unlikely I will be attempting much more than playing through this device for a day or two!
Click to expand...
 
Hi mattpeyton,

I have 2 questions for you:

1- are you using BlendIR to do the capture? I don't think you mentioned it

2- When you compare the capture and the original, what are the two different setups, form the guitar to the final track? Because there must be some obvious difference, like not having the same guitar power amp for example.
 
Here are photos of the booth - the baffling and the cabs in question. I'm using Blend IR.

Capture: Computer-Apollo-Behringer NU1000 amp, bridged-Cable-Cab/Royer 121-API A2D Interface-Computer

IR PLAYBACK Guitar-Marshall Jubilee-Rock Crusher-Torpedo CAB-*IR FILE CREATED ABOVE*-Apollo-Computer

Live Guitar: Guitar-Marshall Jubilee-CAB IMAGED ABOVE-R121-API A2D Interface-Computer.

The loss of 'thump' and balls is easy to hear.... HOWEVER I have found a cheap solution. Buy all the Ownhammer IRs... (and some of yours too). Much better and less deafening..... Cheaper too (returning the Behringer).
 
The things I notice are...

a) I'd suggest trying a high-powered solid state power amp for IR creation (vs a attenuated tube power section!).

b) I'd also suggest losing the baffles around the cab, and perhaps moving the mic back somewhat to try to find a room node that's adding some bottom since that's what you're looking for (assuming you can't get it from moving the close mic away from the dust cap while relying on proximity effect?).

Seeing the IR is truncated to about 20ms or so, you won't get any unwanted room tone with the mic back a bit, though whatever room nodes are in your environment can influence the IR's freq response (trial and error etc).

c) You can also try moving the cab to a corner of the room as well (more low end build up in the corners unless they're bass trapped etc).

d) BlendIR also has a 31 band EQ included, so feel free to EQ your captured IR's as well.

Good luck...

mattpeyton":3qdqvnig said:
Here are photos of the booth - the baffling and the cabs in question. I'm using Blend IR.

Capture: Computer-Apollo-Behringer NU1000 amp, bridged-Cable-Cab/Royer 121-API A2D Interface-Computer

IR PLAYBACK Guitar-Marshall Jubilee-Rock Crusher-Torpedo CAB-*IR FILE CREATED ABOVE*-Apollo-Computer

Live Guitar: Guitar-Marshall Jubilee-CAB IMAGED ABOVE-R121-API A2D Interface-Computer.

The loss of 'thump' and balls is easy to hear.... HOWEVER I have found a cheap solution. Buy all the Ownhammer IRs... (and some of yours too). Much better and less deafening..... Cheaper too (returning the Behringer).
Click to expand...
 
a) the NU1000 is a 1000 watt solid state amp

b) since the baffles don't effect the sound in a negative way when it's live 115 DB, why would it effect the sound when it's both lower and creating an IR?

c) see B

d) tried it but can't use it 'live' only on a file that I import (so it's very difficult to judge how the IR responds under my fingers)

My solution for the moment was to buy more of YOUR IRs, more OwnHammer IRs, and return the amp! In other words, I gave up and went with what was created previously (and better than I can do).
 
Cool, I use my Two Notes cabs most often as I love the real-time virtual mic positioning, but I have the Reswirez and OwnHammers for other stuff as well.

Since you're experienced with cab mic'ing, check out the Redwirez as they're a lot more flexible with regards to mic placement vs the OwnHammers.

Sorry, I miss read your capture chain.

These baffles...

http://peytonphoto.photoshelter.com/gallery-image/guitar-room/G00005RF0aBTtqx4/I0000zv4H7sq.SwM

...do limit your mic positioning, so my thought was to lose them to be able to move the mic farther back to find a room node that's boosting the low end is all (seeing you wanted more bottom end).

The WOS III and the Torpedo H/W all offer EQ, or you can use a EQ plugin post the cab sim if desired for real-time adjustment, so find what you want with them in real-time, then process the IR accordingly.

Note that I'm not a Two Notes employee, just a satisfied customer.

Ciao...

mattpeyton":2a1oigzy said:
a) the NU1000 is a 1000 watt solid state amp

b) since the baffles don't effect the sound in a negative way when it's live 115 DB, why would it effect the sound when it's both lower and creating an IR?

c) see B

d) tried it but can't use it 'live' only on a file that I import (so it's very difficult to judge how the IR responds under my fingers)

My solution for the moment was to buy more of YOUR IRs, more OwnHammer IRs, and return the amp! In other words, I gave up and went with what was created previously (and better than I can do).
Click to expand...
 
You must log in or register to reply here.
Back
Top