Changed my desk and took some REW sweeps

[bikescene]

I recently put in a new desk in my basement space to get some of my outboard gear directly in front of me. I thought about building a desk, but chickened out in the end and bought a RAB Audio LS840. Some Cyber Week cart discounting at Sweetwater pushed me over the edge, but the regular price is a a bit spendy for a small MDF desk. It has 8 RU of space and is a compact 40” width, which were the main reasons for buying the desk.

I don’t have everything wired in yet, but having EQ and compression knobs to turn in front of me makes things much simpler for me.

I took some measurements in Room EQ Wizard to remind myself to fix the room in 2025 before buying more gear. I’m staying with my JBL LSR305 until I make the jump to nicer monitors. These speakers are apparently useless under 35Hz. The monitors were spaced 48” apart, and I used a Behringer ECM8000 mic for measurements.

I’ve got some panels in the corners. For example, the right corner:

The graphs below of the Left and Right speakers are at 1/24 octave smoothing, from 30Hz to 20k. Oof. Looks not so great. Maybe +/- 11dB up to 1k, and +/- 5dB above. I zoomed in the Y-axis in REW to get a better idea visually what was going on.

I also set it at 1/3 octave smoothing to look at something a little prettier. Still a huge bump in the 60-70Hz range, but +/- 5dB everywhere else so I can pretend things are fine.

Spectrograms.

And a 1/24 octave plot of the bass-low mid area of both speakers.

The problem at 140Hz is something I will look into. It’s most likely the ceiling. I have enclosed pipes above my listening space. That I’d have to get a cloud under. I stuffed some Rockwool in my drop ceiling but it’s not enough. I may build a 2x4 frame to lay a Rockwool panel above my listening space.

 

[MirrorProfiles]

Not too bad!

The 140hz thing looks strange on the spectrogram - if you play a 140hz sine tone in your room does anything resonate?

Are you speakers and listening position in the centre of the room? Ideally you’d want to get the response from each speaker a little more even.

How is the absorption at first reflection points? Do you have a cloud?

Personally I’d move those tubes to the back of the room and move some of those panels from the back of the room to your front sides. Clamp down hard on 1st reflection points, the front wall shouldn’t need any absorption

 

[MirrorProfiles]

Our ears don’t really hear at 1/24 resolution and those curves will change a good bit just be moving your head slightly. There is much more to how speakers sound than what the mic picks up at a certain position, our ears are hearing lots of very short reflections of sound arriving at different times.

Frequency plots are helpful for some things but most of the time 1/6 or 1/3 is fine just to get an idea of what’s going on.

Spectrogram shows what’s going on better. Try and get those decay times below 200ms - absorption is unlikely to do much below 100hz but there’s a bit of room to improve above that. As I mentioned above, cloud, side walls at 1st reflection points, then rear wall. To reduce decay times below 100hz you’ll need resonance based traps.

 

[bikescene]

@MirrorProfiles It very well could be a tom from my drums. My snare audibly sounds from a sine sweep if I forget to turn the snares off.

The room and distribution of equipment not symmetrical at all. There’s a bathroom in the back that makes the room kind of a U shape. Also stairs with a bunch of cabs underneath to my left.

I will try moving some more panels to the back. I’ve got 1 directly behind me, but should add more. I think a cloud is one of the first things I’m going to try in 2025.

I’ve been dragging my feet with panel assembly the last half year, despite having all the materials.

 

[MirrorProfiles]

@MirrorProfiles It very well could be a tom from my drums. My snare audibly sounds from a sine sweep if I forget to turn the snares off.

The room and distribution of equipment not symmetrical at all. There’s a bathroom in the back that makes the room kind of a U shape. Also stairs with a bunch of cabs underneath to my left.

I will try moving some more panels to the back. I’ve got 1 directly behind me, but should add more. I think a cloud is one of the first things I’m going to try in 2025.

I’ve been dragging my feet with panel assembly the last half year, despite having all the materials.

140hz could definitely be from the drums.

The more symmetrical you can get the response the better - that’s largely down to getting similar distances from walls. That’ll really help lock things in and should essentially cost nothing to do.

The frequency response curves aren’t bad at all. You actually want to have a bit more low end and a natural roll off as you go higher. Ruler flat doesn’t sound very good, most control rooms aim for a gentle downward slope (like your left speaker is doing).

Do your speakers have any kind of adjustment on the back to roll off? you might be able to smooth out the very lowest stuff that way. I wouldn’t worry about the narrow dips at 1/24 at all, just focus on decay times, symmetry and making the room feel good. Absolutely on the right track

 

[bikescene]

140hz could definitely be from the drums.

The more symmetrical you can get the response the better - that’s largely down to getting similar distances from walls. That’ll really help lock things in and should essentially cost nothing to do.

The frequency response curves aren’t bad at all. You actually want to have a bit more low end and a natural roll off as you go higher. Ruler flat doesn’t sound very good, most control rooms aim for a gentle downward slope (like your left speaker is doing).

Do your speakers have any kind of adjustment on the back to roll off? you might be able to smooth out the very lowest stuff that way. I wouldn’t worry about the narrow dips at 1/24 at all, just focus on decay times, symmetry and making the room feel good. Absolutely on the right track

The speakers have a +/- 2dB trim in the back. I might be able to sneak in some more sweeps this week to play around with placement of treatment and obstructions. Thanks for pointing some of these things out.

Something I’m also trying to wrestle with is cable management. I’m wire things up a little more deliberately and not make too much of a mess. I’ve used some split duct to provide some physical space between power and audio cables. I need to get some labels for my label maker. I’m trying to replicate what I’ve seen from my day job. But I don’t quite have the touch of an electrician.

 

[MirrorProfiles]

I’ll dump some amazon links for cheap cable management things I like:

https://amzn.eu/d/2xIbSVg

https://amzn.eu/d/gaj55St

https://amzn.eu/d/aFBHWuL

https://amzn.eu/d/10VpiFr

 

[László]

Looks great to me.