Load Box coloring tone problem

[RealAmpsAreDead]

I tried to make my own IRs. Whenever I compared the IR I captured to the amp / speaker recording it just did not sound the same. I drove me crazy!! I was aware that a load box can color the tone but never thought that much. The moment I used the "through" of the Suhr load box and connected the actual speaker - there it was - the same tone!
Can someone explain me why the Suhr Load colors the tone that much? I guess it has something to do with the impedance curve? I always thought that a load could color the tone but I never thought in such a "drastic" way...
Here are my recordings:
https://www.dropbox.com/scl/fo/d6ks...rzcxyOwo?rlkey=06x40pmq58pdjn8trc6mde7ml&dl=0

Does that mean that you can actually never really trust any IR promo vid cause it can sound quite different when you use it with your load? Or am I missing something here?

I used a Grossmann Iso Box with a 16Ohm Vintage 30 speaker and a SM57.

 

[manfifi]

Yes, it's almost certainly the interaction between the amplifier and the speaker's impedance curve. A purely resistive load box changes the behavior of the power stage, so what comes out of the amplifier is no longer the same signal even before the IR. When you use the through-circuit with the actual speaker, the amplifier "sees" the correct load and everything sounds the same again.

Mini Militia App Lock​

 

[tjnx]

Does that mean that you can actually never really trust any IR promo vid cause it can sound quite different when you use it with your load? Or am I missing something here?

yep in addition to other things.. fun stuff eh?

 

[RealAmpsAreDead]

yep in addition to other things.. fun stuff eh?

That explains at least why so many IRs kinda feel weird as well to play. It‘s so much better just through a real speaker in my ISO Box.

What „ofher things“ do you mean?

 

[tjnx]

That explains at least why so many IRs kinda feel weird as well to play. It‘s so much better just through a real speaker in my ISO Box.

What „ofher things“ do you mean?

In my experience, IR length (truncation), the load used to capture, the preamp used and their final monitoring setup all kind of influence how they're dialed in. Its all going to sound just a little different on your unique setup and sometimes those small differences can seem impossible to overcome. It won't sound bad per se just not quite right.

Even though the load is 'reactive' its still a snapshot at a given power level if that makes sense... you may like it somewhere else. Think of how different your amp can sound day to day due to power from the wall and temperature. An IR or load will be fixed in those scenarios but something more flexible could be desired.

For example some of the MirrorProfiles compensate for which load you use through an eq curve. If you don't have that box it will sound different, sometimes something like a direct line out box with an uncompensated (clean) IR may give you better results. If your IRs don't have these options they probably wont sound as good due to the mismatch.

Other times when people are doing demos they route the line signal through a DI before applying the IR in a daw for the video. The secret sauce in those cases could be the fact that they're using an active Countryman DI and you're using the more transparent one on your interface.

Just a bunch of small things like that. I've just found that whether you mic or go direct you still gotta tweak almost for the day, just like live playing. This realization kinda sucks because its not quite the easy button it claims to be, but its still a great tool.

So far the most effective tips I've got from people here have been to use the Bertom Denoiser Classic on my DI in and match the filtering on my IR loader with the speaker response, ie putting cuts at 75hz and 6k. Modelers / IRs seem to do better if you can minimize the noise floor.

I've yet to find a modeler / IR that doesn't sound aliased on palm mutes, still prefer mics.

 

[RealAmpsAreDead]

All in a YT vid now!

 

[tjnx]

All in a YT vid now!

Great video! You can really hear the difference

 

[RealAmpsAreDead]

Great video! You can really hear the difference

Thx! Yeah - actually I am suprised that not more of the IR producers talk about this. And I think its quite annyoing to find a fitting IR with your load box, that feels right too out of those 10000000 IRs in those 10000000 packs haha so I am happy to stick with real speakers in my ISO box…

 

[tjnx]

Thx! Yeah - actually I am suprised that not more of the IR producers talk about this. And I think its quite annyoing to find a fitting IR with your load box, that feels right too out of those 10000000 IRs in those 10000000 packs haha so I am happy to stick with real speakers in my ISO box…

Amen. I almost built an ISO box but have just been recording quietly with a 412 and its given me the best results so far. Just had to wipe my machine and backed up all my IRs... loads and loads of them and I only use a handful. Its a tiring game to play.

 

[Nitrobattery]

The Suhr mimics the impedance curve of a 4x12 loaded with G12M Greenbacks. It's partly why it sounded closer with the Creambacks, but very different with the V30's. Unless you have an exact snapshot of the cabinet you're using, it's always going to be different.

That's the whole appeal of the new Friedman unit. It'll measure and bottle the impedance curve of the interaction with your amp into your actual cabinet and then you can store it.

For what its worth though, you can EQ match the differences between the mic'd tone and what the loadbox is doing and print an IR with that EQ curve built in.

 

[RealAmpsAreDead]

The Suhr mimics the impedance curve of a 4x12 loaded with G12M Greenbacks. It's partly why it sounded closer with the Creambacks, but very different with the V30's. Unless you have an exact snapshot of the cabinet you're using, it's always going to be different.

That's the whole appeal of the new Friedman unit. It'll measure and bottle the impedance curve of the interaction with your amp into your actual cabinet and then you can store it.

For what its worth though, you can EQ match the differences between the mic'd tone and what the loadbox is doing and print an IR with that EQ curve built in.

Looking forward to that new Wampler / Friedman device too!

 

[csguy0]

The Suhr mimics the impedance curve of a 4x12 loaded with G12M Greenbacks. It's partly why it sounded closer with the Creambacks, but very different with the V30's. Unless you have an exact snapshot of the cabinet you're using, it's always going to be different.

That's the whole appeal of the new Friedman unit. It'll measure and bottle the impedance curve of the interaction with your amp into your actual cabinet and then you can store it.

For what its worth though, you can EQ match the differences between the mic'd tone and what the loadbox is doing and print an IR with that EQ curve built in.

Agreed, can't wait!

 

[saxxamafone]

The Suhr mimics the impedance curve of a 4x12 loaded with G12M Greenbacks. It's partly why it sounded closer with the Creambacks, but very different with the V30's. Unless you have an exact snapshot of the cabinet you're using, it's always going to be different.

That's the whole appeal of the new Friedman unit. It'll measure and bottle the impedance curve of the interaction with your amp into your actual cabinet and then you can store it.

For what its worth though, you can EQ match the differences between the mic'd tone and what the loadbox is doing and print an IR with that EQ curve built in.

And I’ve heard st rock is best for an accurate v30 curve