LF Resonance Fix for Boomy FRFR

Well, the original post describes it in more detail, but it is basically amps (at least the ones I'm using) that have no negative feedback. Honestly, I'm starting to wonder if I don't have something else going on with how I'm setting those amps because it seems like others would be having this same issue or could reproduce it quite easily: pick an amp, say the Badger 30, add a cab and play a low G (around 100Hz) and compare it to the some other notes.

Have not tried the Badger

How about Fender amps (Twins,Tweeds etc)?
 
Well, the original post describes it in more detail, but it is basically amps (at least the ones I'm using) that have no negative feedback. Honestly, I'm starting to wonder if I don't have something else going on with how I'm setting those amps because it seems like others would be having this same issue or could reproduce it quite easily: pick an amp, say the Badger 30, add a cab and play a low G (around 100Hz) and compare it to the some other notes.

For that room with your setup and guitar, seems like the speaker tab in the amp block is a solution. I would say nothing wrong with that.

Richard
 
If you're only getting 'boomy-ness' around one note then it's probably not a good idea to cut controls that affect the whole of the low end like 'bass' and 'LF res' as it may leave you sound that's a bit thin and weak.

It sounds to me like a room node which is best attacked with some surgical PEQing. Try placing a PEQ block just after the Cab, set the Q to 10, level to around +8db and start with the frequency around where you suspect the node to be (also make sure you're on 'peaking' if using the first or last tab). Then sweep the frequency up and down and leave it at the place you think the offending frequency is at it's loudest. Then reverse the level to minus db and set to a value where the target frequency sounds the same volume as the other notes.

I practice in a room that has a node at 168hz and I've ending up PEQing that frequency to -4.5db on a Q of 10. Sounds great.
 
Would the room be the cause if the same room does not exhibit the behavior on amp models with negative feedback?

Yes, because different amps/cabs have different emphasized frequencies, and different rooms have different resonant frequencies further varied by positioning in the room. It's not a lot different than a speaker cab itself. Think of it this way, speaker is to cabinet as cabinet to room, change a variable of any one part and a lot changes. Ever played the same speaker in two different sized cabinets?
 
Boominess on one note is almost always a room mode. My office at home has a nasty mode right between low B-C (2nd-3rd fret on A string).

If that mode happens to be near the same frequency as the amp's LF Resonance then you will exacerbate the problem even more. If the amp has no negative feedback it will make it still worse.

The ultimate solution is to treat the room. This can be expensive and is often impractical.

The next best solution is to correct the room There are room correction products that basically use a reference mic and measure the room response and apply corrective EQ. The best room correction products use FIR correction filters. The cheaper ones use IIR filters (parametric EQ). There are some new products that claim to not distort the phase.
 
For general absorbtion, I hear (but haven't verified) that the absorber needs to be 1/4 wavelength thick. Let's say that means 1/8 wavelength of material on each wall.

C = 125hz = 8 ft wavelength. So maybe a 1 ft deep absorber on each wall ! Sounds like a tuned absorber would be better...

Not that it matters, but that's actually the first harmonic of a 62.5 hz resonance. And let me guess, floor to ceiling is 8 feet *and* wall-to-wall is eight feet !
 
This thread is awesome. Over the years I've noticed things like this with all sorts of amps, and I never thought to blame the room.
 
Boominess on one note is almost always a room mode. My office at home has a nasty mode right between low B-C (2nd-3rd fret on A string).

If that mode happens to be near the same frequency as the amp's LF Resonance then you will exacerbate the problem even more. If the amp has no negative feedback it will make it still worse.

The ultimate solution is to treat the room. This can be expensive and is often impractical.

The next best solution is to correct the room There are room correction products that basically use a reference mic and measure the room response and apply corrective EQ. The best room correction products use FIR correction filters. The cheaper ones use IIR filters (parametric EQ). There are some new products that claim to not distort the phase.

I've got a treated room but I tried version 1 of this too

IK Multimedia | ARC System 2

Was not impressed. But from reading about their version 2 I might upgrade and give it another go.

Version 1 sounded bad in the mid band to me.

Richard
 
I've got a treated room but I tried version 1 of this too

IK Multimedia | ARC System 2

Was not impressed. But from reading about their version 2 I might upgrade and give it another go.

Version 1 sounded bad in the mid band to me.

Richard

The problem with all these products is that they can only correct the response at a particular position in the room. There is no substitute for a correctly designed room. Whenever we go to the studio it's a treat for me because I get to hear the Axe-Fx perfectly reproduced.
 
The problem with all these products is that they can only correct the response at a particular position in the room. There is no substitute for a correctly designed room. Whenever we go to the studio it's a treat for me because I get to hear the Axe-Fx perfectly reproduced.

Amen! Love any kind of tracking or mixing in a pro room.

I bought my current house because the garage has a 14' ceiling and would be a great room with decently spaced room modes.

I treated it with about 60% coverage of 6" 2x4 703 panels first.

But then the wifey got into remodeling mode and the funds ran out :)

Can't complain though, I mix in another room at the house that I treated with realtraps. That's the room I tried the ARC system on. The cubic volume is really just too small and I've got 3 clusters of axial modes around 425 (A).

Richard
 
My fix was easy.

I returned the CLR and purchased an amp/FRFR solution which worked great with the Fractal Audio Axe-FX right out of the box.

No more "Boom"

Now I can spend my time playing and gigging instead of tweaking!
banana5.gif

What was the amp/FRFR that worked for you?
 
Amen! Love any kind of tracking or mixing in a pro room.

I bought my current house because the garage has a 14' ceiling and would be a great room with decently spaced room modes.

I treated it with about 60% coverage of 6" 2x4 703 panels first.

But then the wifey got into remodeling mode and the funds ran out :)

Can't complain though, I mix in another room at the house that I treated with realtraps. That's the room I tried the ARC system on. The cubic volume is really just too small and I've got 3 clusters of axial modes around 425 (A).

Richard

Out of curiosity, is there a suggested or "ideal" minimum size for a room as far drawing the line for treatment? I know some treatment is always helpful, but curious where the line starts, so to speak. Any suggestions on a particularly good source for learning these specifics?
 
If you're only getting 'boomy-ness' around one note then it's probably not a good idea to cut controls that affect the whole of the low end like 'bass' and 'LF res' as it may leave you sound that's a bit thin and weak.

It sounds to me like a room node which is best attacked with some surgical PEQing. Try placing a PEQ block just after the Cab, set the Q to 10, level to around +8db and start with the frequency around where you suspect the node to be (also make sure you're on 'peaking' if using the first or last tab). Then sweep the frequency up and down and leave it at the place you think the offending frequency is at it's loudest. Then reverse the level to minus db and set to a value where the target frequency sounds the same volume as the other notes.

I practice in a room that has a node at 168hz and I've ending up PEQing that frequency to -4.5db on a Q of 10. Sounds great.

thank you for this advice, because i have a problem on C and C# on at 138hz.
 
Out of curiosity, is there a suggested or "ideal" minimum size for a room as far drawing the line for treatment? I know some treatment is always helpful, but curious where the line starts, so to speak. Any suggestions on a particularly good source for learning these specifics?

A small part of room design are the axial modes. These are L, W, H of your room as they affect which frequencies will be boosted and where the "nulls" are. (See the website below for a deeper explanation.) Smaller rooms have these modes grouped together; the same frequency is boosted in L, W, and H. For example, I have a cluster of boosts around 425-445 in all three L, W, H. When they combine like that, there is an even more pronounced hump around that frequency.

I started by using the realtraps website: RealTraps - Home

They have some great white papers and links about rooms.

The subject of rooms and room treatments varies so widely and involves so much information. There are many books etc. on the subject.

The very fundamentals for me were:

1. Create a reflection free zone for mixing.
2. Eliminate flutter echo.
3. Get as much bass trapping as I could afford.

I ended up being a customer so I sent them a CAD drawing of my mix room and they recommended the panels and placement.

When building new, there are some tried and true "golden ratios" of L, W, H that various experts and gurus recommend.
 
barhrecords- thanks for replying to my question. I missed this post...

I'm interested in the "golden ratios" with respect to building a new room from scratch. I'm contemplating building a single room in my backyard (was going to be a nice storage shed) to write/record, etc. I'll start digging around..
 
I had flubber issues too after the FW10 update so I went to the amp block,held down the bypass button to reset it to default settings....no more flubber problems with that particular amp
 
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