No. I've known how - and had the means - to collect reflection-free IRs since 1985.So I guess those IR's in there were before you discovered how to make them fully reflection free?
Hasn't Jay already spoken to this in post #301?@Jay Mitchell I've been thinking about the signal chain, from sine wave sweep to the recording of the IR.
Simplified chain: signal generator > amplifier > speaker > SOUND IN AIR > microphone > pre-amplifier > DAW... basically all of the transformations of the signal before deconvolution.
With regard to speaker IR's, when you use the term 'baked in' to describe room reflections within the first milliseconds of the capture affecting the subsequent frequency response of the IR, I understand that as an error in the response of the speaker under test.
But then I think about what I want, and/or don't want, to be 'baked in' with regard to the signal chain of the recording, it occurs to me that my choices are individual components: the speakers amplifier, the microphone, and the mic pre, as well as the knowledge that my signal generator and DAW are calibrated and doing what they are intended to do.
@AlbertA describes the care it takes to obtain the IR measurement of the SUT in #314.
IR's taken from the amplifiers are easy enough to do.
IR's taken from the transducers take a lot more care.
What I'm getting at is this: if the goal is to obtain a 'perfect reflection' of the speaker, that is but one component in the signal chain.
If great care is taken to accomplish that, it stands to reason you would want 'perfect reflections' of each component in the signal chain.
Which brings me back the the term 'baked in'; when I cook, I don't buy pre-mixed, I add to taste.
I don't like it when my paprika is already mixed in with the chili, or the sugar with the salt.
Assuming IR's replace each component in the signal chain when they are convolved, I want the individual IR ingredients in their "freshest" (best possible measurements) so I can do the cooking myself.
What are your thoughts on this?
And - as I have carefully pointed out - because you want the impulse response of the speaker, you must take steps to eliminate the effects of all the other components in the test chain. The mic, amp, and preamp are straightforward: quality examples of these components have near-ideal impulse responses and - this is important - impart no sonic signature of their own. Eliminating the acoustic signature of the test space is the challenging part. That's what this entire thread is about.if the goal is to obtain a 'perfect reflection' of the speaker, that is but one component in the signal chain.
See above.Assuming IR's replace each component in the signal chain when they are convolved, I want the individual IR ingredients in their "freshest" (best possible measurements) so I can do the cooking myself.
Capturing an IR of a tube amplifier is pointless cuz IRs can't reproduce non-linearities (i.e. compression, distortion, etc.).If I'm reading you right, if I make an IR of a Deluxe Reverb amplifier, I would first obtain the IR response of whatever speaker is in the cabinet, using a testing amplifier, and then I would convolve that with one of many IR's of fender amplifier tube circuits.
You are making this far more complicated than it is.I'm wondering about what constitutes being 'baked in' for a combo amplifier IR.
And, when you're using an IR of the cab, it's pretty much always going to be in a modeler or software simulation. That's what will simulate the amp. The IR is there to simulate the cab.A Deluxe Reverb amplifier was conceived as a combination of the amplifier and the speaker, they go together as a matter of convenience and portability.
You are not. Impulse responses are useful to capture linear properties of devices. Guitar amps are highly nonlinear. You can't use impulse responses to capture their properties.If I'm reading you right,
I see, that makes sense, thanks @dlc86.But I think it's better to leave those tasks to modelers imho.
Ok, didn't mean to get off track, getting back to sound in the measurement space...Impulse responses are useful to capture linear properties of devices.
One of the files has "4m" in the title. That could be possible with the mic and speaker near corners. In any case, the magnitude of the reflections is such that the effort to take that data in the chamber is wasted.Based on the images of the chamber included with the IR's, 10 feet appears realistic.
Yep, both samples I posted are amp only (Helix BE-100) + delay, no Eq and no post prod.I also find it encouraging that users here are reporting that they don't have to go through EQ contortions with the far-field IR's that you generally have to do with near-fields, particularly in taming/shaping the low end.
I don't post a lot on TGP, but it's interesting that I found a post of mine from 2013 regarding far-field IR's (this topic brings me out of the woodwork):Ya know, thinking about this I think Jay should write a short instruction manual on how to do far-field IR captures. Perhaps some of the IR vendors out there will then be inclined to rent a space and do some. Maybe some of the IR guys have access to a large enough space.
Could be, wait for it....
... a game changer.