Home made IR continued...

[Cuki79]

Hi everyone,

For those who missed the previous threads, here are the links:
First IR thread about the Lyric
2nd thread about Doug and I trying to find a good IR process
My IR for a Martin HD-28 + TA Amulet

To summarize, I've been making IRs for almost a year now. And Doug and AeroUSA always told me the sound was kind of distant. I could actually feel it. I can think about two reasons. First the Mic IR involves a slower/sweeter attack. Second, the reverby nature of the IR can make the overall tone muddy. The Tonedexter "character button" strategy helps but does not solve everything.

My IR process is close to Tonedexter's patent but with my own cooking secrets.

Here I will illustrate the Fishman strategy applied to my own IRs.

Fishman Aura offers a blend pot. To include that feature, I have built an all analog buffer-blender circuit based on a wellknown schematic on the net. It enables to have a - no latency - dry path that brings a more "immediate" response.

To take advantage of that, I have customized my initial IR by removing from it the initial "attack". We don't want to have the dry path being followed by a delayed secondary "attack" due to the digital latency ont the wet path. So the IR only includes the "Resonance tail" from the guitar.

As a consequence the tone closest to the mic should be between 50% and 70% of the pot maximum position.


NB: I am playing with my fingers (no pick).

Cuki

[Cuki79]

Last post,

I explained how I removed the initial attack of the IR (there are subtle details about why I do that but it would be too complex to explain).

Today I went a bit further. I measured the latency of the digital path


Now I know that the IR convolved signal is blended with 1 ms delay with the analog path.

Instead of blending the original IR without the attack... I removed 1ms of the IR. As a result when the guitar body resonance is blended, it is perfectly synchronized with the analog path.

I have no delay on both path now.

The result is even more defined and punchier.

I am thrilled I finally get the best of both worlds.

To conclude:
1) If one would compare that to Tonedexter or Fishman Aura. A similar process is made but I keep all the original content analog and the digital treatment is "added in sync" to avoid the "distant" feeling.
2) Or course if you play very far from your monitoring device, this does not make any difference since 3 feet of sound propagation in air is equivalent to 3 ms delay. You'll always have the sound from the monitor delayed from the sound of your guitar.

EDITED: Does not work that good. I played longer and it's a bit bright and weird... I think just removing the attack sounded fuller after all.
Cuki

[Cuki79]

Here is a my first blend prototype.

It's the box under the EPSI. It provides blending and Li-ion battery operation to the pedal. The pot on the right is the blend pot.


I did a specific test. Since the EPSI pedal is stereo, I put a customize blended IR on the left side and the standard IR on the right side.

The left side is thus blended with the analog signal....
Whereas the right signal goes straight to the amp.

The conclusion is... It's not miles better.

* The analog blend provides better dynamic (thanks to the Amulet) and more defined attack and punch.

* The full digital IR always sounds more mic like. But it is a bit duller and somehow compressed tone.

Is it worth the pain? (Extra room for the box and second battery for the blending circuit)

I honestly don't know... If you are a singer and a strummer like me it is not obvious.

I'll have some one else try...

Cuki

[SpruceTop]

Cuki,

I appreciate your efforts on behalf of bettering amplified/recorded acoustic guitar tone via Impulse Response research and development. From my listening, the application of IR definitely improves the tone of an amplified/recorded acoustic guitar with a pickup. Thanks for your efforts in this useful and exciting tone quest!

Ken

[Cuki79]

Thanks Ken,

This part is very subtle but I think if someone is not satisfied with either dual source or tonedexter. It is good to know there is something in between. I am pretty sure Fishman Aura uses a digital blend which is something very easy to do and costs nothing but does not lead to the same result.

AeroUSA put the worm in my mind but he really trigged this new experiment when he pointed out that Jorgenson blended his tonedexter signal with the analog pickup signal through UA preamps...

Most IRs have a certain percentage of dry signal (between 50% and 70%) so why this part should go through analog/digital conversion, latency, filters... When it could go all the way analog!!

In my case, I get back the sharpness, dynamic and open "air" of the Amulet... It would probably not work the same with another pickup.

Note that you can't do that with tonedexter since You should remove the "dry signal" part from the IR.