DI capture + IR vs capture with cab - which is more accurate?

Hi everyone,

i am wondering what is the best approach to captures when only considering authenticity to the original sound of the amp/cab?

The Cortex comes with factory capteres that are DI and i see why - this way they can be seamlessly integrated with the rest od the system and included cab IRs.

I did some DI captures of my amps and feel like the Cortex gets really close. But i haven’t had the time to mike the cabs properly and make a full capture. I recently found a full capture of a Tweed Deluxe, which sounds phenomenal - incredibly realistic.

So i am now wondering - is the well miked full capture more realistic than a DI capture + IR of the cab?

I have found if you want the exact sound of a certain amp and cab the way they feel and sound for you in the studio, then the best way is to capture exactly that- the amp and cab together in one capture. If you’re in the Nashville, TN area I would be happy to help you make some captures of your amps anytime.


This might help answer your question. A comparison of full Captures vs DI amp Capture and speaker IR.

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Thank you for the reply and the very kind offer! That would be a blast, but i am located in Europe.
I did some tests myself, so far i get best results with DI captures + IR’s, but i do not have a control room and it is really hard to mike up the cab really good without being able to directly hear the tone of the cab without the full volume blasting you.
I plan to go to a studio to try and capture some of my vintage amps soon.

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Greg, Thanks for the link! I saw that video already, but unfortunately this comparison does not tell much in that regard. For the comparison to be conclusive - one would need an ABC comparison of / real amp through real speaker and mics / full capture of the whole rig / DI capture + IR of the actual cab and the same mics the same way they are set up. So this would all have to be done in one go while the mics are in exactly the same position.
I hope to do this experiment in a studio soon.

Let me see what I can do. I think I have time for this fun little science experiment!


Oh this would be sooo relevant to my interests.
So far i have gotten good results both ways, but it seems like the full capture might be more dynamic/responsive to pick attack. But again, you’d need three apples of the same color to make that comparison.

I’ve been thinking about this today. Honesty everyone might have different favorites. What sounds best to one, might not sound best to all. So let’s discuss a little.

I’m thinking I’ll pick an amp and cab. Make a capture of the amp and cab together as one profile. Then make an IR of the cab. Then do a DI capture of the amp. Then I think I would need to make recordings of each chain, 1. amp/cap capture 2. amp DI capture/IR of cab. AND 3. a recording of the real amp as the control or standard to judge the 1 & 2 against.

Anything I’m not thinking of?

That would be exactly my understanding of it too. It would be very important not to move the mic(s) a bit during the whole thing, as a slight movement there quickly makes the results incomperable.

Another important aspect might be getting the signal level of the white noise while making the IR of the cab as loud as the amp is at its settings used. So that the IR has same amount of smoothing and similar response to the real cab at the actual volume.

The video linked above by aphek studios demonstrates the stark differences one gets with the IRs due to different levels at which they were created.

And, yes, as with everything in art and music - better or worse is totally subjective. To me personally the aik with the Cortex is to get as close as possible to my real amps.

Happy Thanksgiving from Nashville everyone!

So while I was waiting for my turkey to roast, I performed a little science experiment.

Here’s what I used: Mid 60’s Vox Ac30 into a 1-12 cab with a Celestion Blue Alnico speaker. Mic’ed with an SM57 and a Fat Head ribbon mic through a Chander TG2 preamp so I could blend the mics together nicely. I dialed up a nice low to mid breakup sound.

I first did a capture of the amp & cab together. Then a DI capture of the amp. Then immediately make an IR of the cab with the same mics and pre settings. Nothing moved. Then I had an idea. After doing the IR, I though I’d see what happens if I just capture the cabinet as a separate capture and use it with the DI amp capture. It took a little tweaking to get the DI capture and the cabinet capture to play along (a gain structure thing) But the results are interesting and if perfected, might be an option. I’ve noticed that the QC’s IR module adds a little more latency than just using 2 captures in a series.

Then I hooked up my 335 and recorded some guitar bits into pro tools with a DI. Then ran it back through the QC and recorded each preset back into pro tools. Then I did the Ac30 by itself. I’ve level matched the final files in pro tools so the comparison would be best. But other than that, nothing was added or changed in any way.

I’ve made the presets public on my profile. So find me and I’ll share them so you can mess around with them. (sleiweke)

Here’s a download link to the audio files so you can hear them and compare the results.

The IR I made is also included.

Let me know your thoughts.

Happy Thanksgiving! :slight_smile:

Oh, this is very exciting - thanks for investing the time and sharing! I will listen to the clips as soon as i get to my PC and headphones. I will follow you on the cortex app. My user is AmalgamAudio.

sleiweke, you have done this comparison really well!
I importet the WAV files into my daw and a/b’d them (this is the first listen and i did not have as much time as i would have liked to and i will certianly listen some more later).
First impressions:
The DI capture + IR sounds closer to the real amp to me.
The full capture had some break-up going on that was not there in the originals signal and that was a bit harsh (i assume it was not because of clipping?)
The DI capture + separate cab capture (interesting idea btw.!) was actually quite good, but there seem to be some artifacts going on that are not present in any of the others.

So far i i think my preference would be DI capture + IR

But it is a completely different thing, when you have the chance also to play and feel the differences.
So what were your impressions so far? I am very intrigued.

When auditioning and setting up the presets for the tests, I felt like the DI Capture + IR and the DI Capture + Cab Capture felt the most real to me. They really felt like the amp.

I’m going to do some more test with the Cab Capture. I think if the cab captures are done with less volume than the original amp, it will give a more accurate result. I think driving the speaker at the same volume gives it a “gain” characteristic that it should not have. The cab capture should be fairly “static” like an IR.

I think there’s a dynamic-ness to that combo that might be really cool.

So i did some more critical listening and comparisons and yes, to my ear the Full Capture does exactly what i discovered in my tests - it sounds somehow broken up in a way that is not there in the real miked recording nor in DI capture + IR. I see how some people might prefer that sound as such, but i am after smoother, more together sounds and after how the actual amps sound.
I also listened more to the DI amp capture + separate cab capture and tried to look past the weird artifact hissy overtone that is present and yeah, i agree, it sounds also very promising, certainly closer than the full capture. This is a very nice discovery (to me at least), as i did not know this might work.
Still, the DI capture + IR sound closest to source to me.

This is a very nice discovery for me, as i have been using real amps + IR’s for many years now and i always found it was a very functional and flexible approach - glad it works so well with the Cortex.

Time will tell, if this is the “best practice” for the unit, but these initial results sure hint towards that direction.

In my view it is also telling that the factory captures are also all DI captures. So it looks almost like it was intended for this approach in the first place.

I will certainly post my own clips/test results as soon as i get the chance to get to the studio to do it.

After more time with the quad, do you find the best results with captures is a head capture plus an IR? I hope the head plus cab all in one capture can be the winner one day as it would take up one less block and CPU power.

Scroll up to my post from Nov 25th. You can download the results and tell us what you think.

I do both, some amps are hard to capture via DI, I have this boutique amp I can only accurately capture with a microphone, capturing it via DI it loses its hair, sounds somewhat muffled, I have a BSS DI box, gives an accurate capture but mids are sucked out compared to a capture via Torpedo live, this way I capture pre amps and power amps, I have a Power station for heads and cabinets via a SS power amp and microphones, I have good microphones and use white noise and analyzer to get mike position right, on the other hand the flexibility of non mic captures, but my mic captures tend to be the best.

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I think that’s great. Everyone is gonna have their own thing, and their own way of doing it that works for them. I think that’s one of the huge strengths of the QT. It’s gives us these flexible routes to find and capture what we wanna hear. I’d love to hear some of your captures.

Ok, i’ll post my captures of an amp head, FLXR-X2, cathode biased PP, only a few made takes EL84, 6V6 or 6SN7 as power tubes, first mic capture, amp head to an oversized cab with a Celestion AlNiCo Cream, a Beyer M160 ribbon, next I’ll post a capture of the same speaker captured via a SS amp, same mic and the head going through Torpedo live, you have to join em, you will find me under Dutchtouch on Neural presets and captures., under captures you will find them, let me know what you think.

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Looking forward to your results and the captures and thanks for sharing!