Open-Back Cab Issues

[7704A]

Posting this separate from my 4104 thread to encourage more general discussion. Anyhow, I finally picked up on just how much of a difference room placement of an open-back combo makes. I usually have the amp sitting in front of my desk to use as a chair, and when I want to play I hop off and plug in. Well the desk forms a tunnel of sorts in close proximity to the back of the cab, and I noticed in the frequency response plots I was generating that there was suspicious correspondence to the distance from the cab back to the desk's hard back wall. So I blocked off the desk opening and did some before/after comparison.

I was not expecting this much of a difference. I thought it'd be mostly bass response differences I noticed, but it seems to change the timbre and balance too, as well as clarity, which really surprised me.

This first pair of clips shows the biggest timbre change I experience. In the room, after trying it, it seemed like a big enough change that I started questioning if I'd played the riff differently and had to switch back and forth a few more times to eliminate that possibility.



This second pair of clips is where I noticed the most difference in clarity when playing in the room. I had to go back and forth several times here too just to make sure my sloppy playing wasn't resulting in strings ringing out that shouldn't.



All recorded on my cellphone in the corner of the room, so not great, but illustrative. Anyone else fooled around with this sorta stuff before? I'm even more motivated to make some proper cabs now.

 

[midnightlaundry]

Yeah man, mics hear things differently.
We kinda fake it but putting mics up close to recreate what hear hear far away..
Mic Companies that do this shit 24/7 carve their response EQ's carefully and really do a great job.
Nowadays, everything is EXTREME with more EQ more highs more smash.. More everything.
But really a clean slate listener with just a Mic in the right spot is usually the best representation without anything added..

 

[midnightlaundry]

I think it was Dio's Last I Line Record where they got that snappy Drum Sound by propping up sheets of Plywood around the Drums..

 

[7704A]

Yeah man, mics hear things differently.

Not disagreeing, but I think you misunderstood what I was saying. I wasn't commenting on the difference between what I heard in the room and the recording, but what I heard with/without plywood blocking the desk cavity, which the provided recordings are fairly illustrative of though like you mentioned not perfect.

Funny that you should mention mic coloration though, I ended up doing this quick test after getting the PZM to sound near-identical to what I heard in the room (which was my goal) and noticing that I subjectively liked the close-mic'd 57 recording more in some ways. That prompted me to look more closely at the graphs, and that's when I noticed that the 57 overtook the PZM/room response at a frequency that roughly corresponded to the geometry in my setup. Hence using plywood to tweak that.