At a typical distance of, say, 5 ft. we are only in the far-field at frequencies below roughly 3 kHz. Above that we are in the Fresnel zone.
Youse guys!
Hey Leon, Can you do a Vdo about this topic.? That will really help some of us understand what's it all about?
Stupid question of the day - would the best way to record these not be in one of these 'dead' rooms the microphone manufacturers use? I.e. completely sealed and reflection free
1. Close-micing a cabinet is not problematic. It's been done for years and solves a lot of technical issues. It may sound different than listening to that cabinet at distance but it's no more right or wrong than any other micing technique.Here's a simple, if a little long-winded, explanation:
The premise is that close micing a cab is problematic (from a technical standpoint at least... you might like the sound and it's what engineers have been using for years) for a few reasons:
So the obvious solution would be the move the mic further from the cabinet, and that does solve the issues above, with the exception of the floor reflections. But... as you'd probably expect, micing a cabinet from a distance introduces reverberation from the room which has its own issues. Enter reflection-free far-field impulse responses.
- Speaker cabinets produce sound from more than just the speaker and when you listen to a real cab in a room you're hearing the sound coming from the cab as a whole, not just the speaker. Close micing picks up very little of the sound from elsewhere because the mic is close to the speaker.
- If the cabinet has multiple speakers the mic only picks up sound from one.
- Many mics exhibit proximity effects increasing the bass response when they are close to the sound source.
- The sound from the speaker bounces off the floor causing peaks and nuls in the waveform because of phasing (meaning that some frequencies are pronounced and others too quiet in an unnatural way.
Simply put, taking an FFIR involves three things:
The result is a 'pure' capture of the sound of the cabinet in its entirety and with none of the room. The benefits being:
- Moving the microphone further away from the cabinet, eliminating the first three problems discussed above.
- Placing the microphone on the floor so any reflections from the floor only affect very high frequencies that don't matter for our purposes.
- Using a short impulse and a large space so that the entire impulse reaches the microphone before any reflections from the room can.
Jay Mitchell is the biggest force behind reflection-free FFIRs (I want to say he came up with the idea, at least for modelling, but I might be wrong) and he has a long and fascinating threat over at TGP called IR Properties. It's worth a read if you want to understand it deeper.
- It is a truer representation of the way the cabinet sounds.
- Which in turn means when it's played through FRFR speakers it sounds more like a cabinet in the room.
- A sound that usually doesn't require high and low cuts that most of us routinely apply to close-miced cabinets.
Here's a simple, if a little long-winded, explanation:
The premise is that close micing a cab is problematic (from a technical standpoint at least... you might like the sound and it's what engineers have been using for years) for a few reasons:
So the obvious solution would be the move the mic further from the cabinet, and that does solve the issues above, with the exception of the floor reflections. But... as you'd probably expect, micing a cabinet from a distance introduces reverberation from the room which has its own issues. Enter reflection-free far-field impulse responses.
- Speaker cabinets produce sound from more than just the speaker and when you listen to a real cab in a room you're hearing the sound coming from the cab as a whole, not just the speaker. Close micing picks up very little of the sound from elsewhere because the mic is close to the speaker.
- If the cabinet has multiple speakers the mic only picks up sound from one.
- Many mics exhibit proximity effects increasing the bass response when they are close to the sound source.
- The sound from the speaker bounces off the floor causing peaks and nuls in the waveform because of phasing (meaning that some frequencies are pronounced and others too quiet in an unnatural way.
Simply put, taking an FFIR involves three things:
The result is a 'pure' capture of the sound of the cabinet in its entirety and with none of the room. The benefits being:
- Moving the microphone further away from the cabinet, eliminating the first three problems discussed above.
- Placing the microphone on the floor so any reflections from the floor only affect very high frequencies that don't matter for our purposes.
- Using a short impulse and a large space so that the entire impulse reaches the microphone before any reflections from the room can.
Jay Mitchell is the biggest force behind reflection-free FFIRs (I want to say he came up with the idea, at least for modelling, but I might be wrong) and he has a long and fascinating threat over at TGP called IR Properties. It's worth a read if you want to understand it deeper.
- It is a truer representation of the way the cabinet sounds.
- Which in turn means when it's played through FRFR speakers it sounds more like a cabinet in the room.
- A sound that usually doesn't require high and low cuts that most of us routinely apply to close-miced cabinets.
Thanks Mate for taking out the time to explain this, I really appreciate your help.
Makes more sense to me now, when I understand it well.
Thanks once again.
Is there anything additional required in the IR capture process for an open back cab? Micing front and back?
When I tried my first FFIR I immediately noticed the punch and pop that I was missing from my favorite 2x12 Celly Blue open back cab. My axe 3 is waiting unopened at home, and the first thing I am trying is these FFIRs!