My bass trap

[unit7]

I recently bought a fat analog console to seriously start mixing my projects. New gear, new situation and new demands on my working space.

Have had the feeling that the low end was a problem in my room. How unusual... So I had an acoustician in my studio recently. He listened and measured. The room (approx 8x4 meters) is treated around the listening position and was very good from 125Hz and up, but had a 25dB dip down to 40Hz. Doctors orders was to build a bass trap/wall (edit: Learned later that it's called a Helmholzt resonator) on the back wall of my studio.

Also had to build a thinner wall where the bass trap ends, I guess to stop some side leakage.

When I put up the first piece of wood last week I thought it would be nice to post some pics here. Now almost everything is ready except that I'm waiting for diffusors (Golden horn) that I expect to arrive on monday. They're going to be 307mm wide and mounted with 30mm space (also doctors orders and dependent of the frequency that are going to be trapped).

Also have to order a door with see thru window for the thin wall.

The trap is 45cm deep (edit: filled with fiberglass wool of softer density than ordinary rockwool, which I believe is to make it work according to the Helmholzt concept) + the diffusors are 13cm, for a total of 58cm. Pretty fat!...

This is the wall when I just had started with the side wall. The part that will have the trap is about 2.8meters wide.

[unit7]

And here's the progress of the work. I'll get back with a new pic when the diffusors are up. Can't wait to listen to see how much improvement there will be!...

[Weasel9992]

How does it work?

Frank

[unit7]

Originally Posted by Weasel9992

How does it work?

Frank

You mean if there's any difference now?
Sat down today for a while and noted that everything sounded a bit more tight and controlled. Not a very big difference in the low end yet. I believe there was some difference though (gotta get a sub!). Of course there was a big difference when listening in the middle of the room. But I was told that the diffusors, even if they only diffuse higher frequencies, with the 30mm gaps is a crucial part of this kind of construction. The lo frequencies will get in there but won't come out...Hopefully! I'll tell you next week!

[unit7]

Finally the diffusors arrived, more than three weeks late

Gonna get them up asap to see how they'll work on my new wall...

[Glenn Kuras]

The lo frequencies will get in there but won't come out...Hopefully! I'll tell you next week!

That seems a bit odd to me. If they test the room can you post some graphs?

[unit7]

Originally Posted by Glenn Kuras

That seems a bit odd to me. If they test the room can you post some graphs?

Thanks Glenn. I only saw the graph on his handheld B&K measuring tool. We did no printout. The graph looked very flat from 150Hz and up. But below there was a 20-25dB dip. The graph was not at all as detailed as the graphs I've seen around here.

I've read many of your and Ethans posts and I believe that you have a slightly different approach than "my" guy over here. I have a feeling that you're a bit more updated... It's just that he's a veteran over here. Done thousands of studios and rooms and very appreciated. But if this doesn't work I'll come running and crying

[Glenn Kuras]

Originally Posted by unit7

Thanks Glenn. I only saw the graph on his handheld B&K measuring tool. We did no printout. The graph looked very flat from 150Hz and up. But below there was a 20-25dB dip. The graph was not at all as detailed as the graphs I've seen around here.

I've read many of your and Ethans posts and I believe that you have a slightly different approach than "my" guy over here. I have a feeling that you're a bit more updated... It just that he's a veteran over here. Done thousands of studios and rooms and very appreciated. But if this doesn't work I'll come running and crying

Maybe I am not understanding what his plan really is, but you can't solve bass issues with diffusion. Well I guess anything is possible, but they would have to be SUPER THICK.

Glenn

[unit7]

Originally Posted by Glenn Kuras

Maybe I am not understanding what his plan really is, but you can't solve bass issues with diffusion. Well I guess anything is possible, but they would have to be SUPER THICK.

Glenn

Thanks again Glenn. Appreciate it.
No the diffusors aren't for the bass frequencies. But if you check the other pics maybe you can see that I've already built a 45cm/18" thick wall. Now I'm gonna mount the diffusors as a surface on that wall. They are to be placed with a certain (30mm) gap between eachother. That measurement is calculated for my room and the center of my bass problem frequency (edit: The Helmholzt resonator was designed to be pretty broadband and take care of everything below 100Hz). So I believe the plan is that the diffusors will scatter 800Hz and up (not a problem in those frequencies before, but since I was going to build a new wall anyway, I guess this is the optimal surface to avoid standing waves) and then the freq's below 800 will be trapped in the wall. I'll let you know how it works, hopefully later tonight as I'm quite eager to find out myself

[unit7]

After a long day of mounting diffusors (and a few hours of tracking lead and backing vocals in between) I'm ready, more or less. Some finalizing touches left. I did notice some difference before mounting the diffusors, but now it's obvious. Very nice! Actually the sound has improved drastically thru my whole room. The bass peak in the middle of my room is gone more or less. I believe there's a slight bass dip about 0.5-1m behind the sweet spot. But doctors orders also are to move my console 30cm forward (which I need some help to achieve) so I'm curious about what that will do too.

After that it would be interesting to do some measuring. The freeware that I downloaded seemed to work pretty unstable with my PTHD system, so I think I'll buy that "fuzz"-whatever-thing instead, since the gurus here seems to recommend it.

And I feel strongly that my room is getting ready for a pair of new monitors... Finally!

[Glenn Kuras]

good deal.

[unit7]

Followed the last orders to move my console+speakers 30cm closer to the front wall, wich I felt improved the sound a little more. However the graph I got from FuzzMeasure wasn't that good. Or would this be normal for Genelec 1030's? Any comments?

[Weasel9992]

Actually I think the graph looks fine. You've got some stuff happening at 1-2Khz, and I'll bet that's console bounce. The other stuff up high could be a number of things. Low end looks pretty good all things considered.

Plots are great and all, but how does it sound? That's what matters. If that 1-2Khz valley is a problem you'll definitely know it.

Frank

[unit7]

Originally Posted by Weasel9992

Actually I think the graph looks fine. You've got some stuff happening at 1-2Khz, and I'll bet that's console bounce. The other stuff up high could be a number of things. Low end looks pretty good all things considered.

Plots are great and all, but how does it sound? That's what matters. If that 1-2Khz valley is a problem you'll definitely know it.

Frank

Frank, thanks a lot!

Well, now I've been listening for a while to a lot of different music. Regarding all the work and money I've put into this, I'm not 100% happy, at least re the bass. I'm not sure about that 1.15kHz. Don't believe I've got a problem with that.

Forgot to mention that I actually kept a -4dB treble tilt on my Genelecs when measuring... The top end doesn't seem to be a problem in my room, and I find the treble on the hard side on my Genelecs so I believe that this insures that my mixes won't get too dull.

The good side is that the sound is more controlled and tight now. In the whole room. I found a very nice spot for bass frequencies about 3 meters from the speakers. I did have this bass peak before (another meter behind) but now the bass is defined at that spot. I can separate the kick and bass when listening from that spot. It actually sounds great at that spot! (but lacking the close up detail in the top end of course) That wasn't at all the case earlier.

But after listening at that spot and moving forward to the "sweetspot" the sound still feels too thin.

After moving the console myself back and forth, testing with FuzzMeasure in between I'm quite exhausted now

However I think that I'll have to plan for the last step I was told to do if this wouldn't work all the way. That is to add 30cm of Rockwool on the front wall. This wall is already treated with up to 70cm in the corners, but only with 10cm in the middle and below 90cm height. So hopefully all the 10cm areas will be 40cm next weekend. THEN, maybe it'll be time for new speakers...

Thanks again that you care! This corner of GS is nice.

[unit7]

After a weekend of hard work I mounted another 35cm of Rockwool on my front wall. Think I'm getting there. Got 10dB more between 60-70Hz + some other improvements. THAT made a difference to the sound!

The peak at 120-140Hz is probably fixed by hanging a final (hope so anyway) absorber in the ceiling. (BTW, still Genelec 1030A speakers w -4dB treble tilt)

[unit7]

BTW, this is how the front wall looked before. I've had my room for 6 years, and this treatment was made by previous owner. Oddly enough I've never really checked how it was made. When examining it the other day it turns out that the light areas are only 4-5cm deep. That includes the areas below the fat corner pieces. Not enough for absorbing bass obviously, so...35cm more for a total of 40cm (16").

And even more surprising, when I stripped the texture/fabric on those fat corners it turned out that there was some kind of Helmholzt bass trap construction inside. I was told to use only soft materials on my front wall, so there went another working day, unmounting that and then rebuilding

[unit7]

Pics to prove... No pics of the new 35cm deeper wall finalized. But it'll look the same as before...

[unit7]

Just got thumbs up from my ME! (emailed him the mix for a check) Jazz project with acoustic bass, and he assured me that the bass wasn't too loud, it was just right. Very, very rewarding. 10 mixes left, so back to work!

[Weasel9992]

Good for you, man. It's nice to be able to work in a room you can trust, isn't it?


Frank

[unit7]

Originally Posted by Weasel9992

Good for you, man. It's nice to be able to work in a room you can trust, isn't it?


Frank

Thanks! Yeah, sooo nice! At lunch I went out to buy a sandwich while the artist listened to the mix a few times. I came back, opened the door, and wow!.. After more than 6 years in this room I can say that the difference is huge!

I use to say that it's strange that one seems to be unwilling to pay for and attend the tools you use the most (all the time). A flashy compressor is much more fun than a good chair, a big computer monitor and good speakers. Now, a good room is on that list too.

[unit7]

This has turned out to be yet another photo diary of building traps. Quite many here already, but what the h*ck. Time for the 3rd and hopefully the last step of my room treatment.

Just finished the frames for the additional traps that are going to hang in my ceiling. Already have 5cm treatment up there, and these 12cm thick ones are going to hang 25cm under the original ceiling with a little space left between these and the old treatment. I'm going to cover almost the whole area from the front wall back to 50cm behind listening position, approx 2.4x4m. Again, I'm very curious about what that will do to the 120-140Hz peak that I got when measuring. I'm working with this little project in between work/sessions, but hopefully I'll have them up and have a new measurement in two weeks.

I also have tested the K+H O300's which I liked. Waiting for the new ADAM series which I want to test before deciding. Really tough decision... Barefoot, K+H or ADAM as it looks right now.

[Glenn Kuras]

Looking good!!!

[unit7]

Originally Posted by Glenn Kuras

Looking good!!!

Thx m8! You guys are the best!

[Blind]

keep em' comin'

[Weasel9992]

Originally Posted by unit7

I also have tested the K+H O300's which I liked. Waiting for the new ADAM series which I want to test before deciding. Really tough decision... Barefoot, K+H or ADAM as it looks right now.

Hmmmm...that's a tough choice. I've heard great things from clients on the Barefoot speakers, but make sure you've got that room treated *thoroughly* for low end. Those speakers will produce every bit of 35Hz, and if your room isn't solid it's going to be a mess. The 0300's have a fabulous pedigree, of course.

Frank

[unit7]

Originally Posted by Weasel9992

but make sure you've got that room treated *thoroughly* for low end.

Thx Frank! Well...I have put 45cm of treatment on my rear wall and 40cm on the front wall, I'm broke (those diffusors...), my hands are sore, my lungs are filled with glassfibre dust and I'm gradually loosing my mind, so if someone tells me that my room needs more treatment I don't know what will happen

[polloymedio]

digging your determination on getting the best sound you can! hope to see more pics!

[unit7]

Originally Posted by polloymedio

digging your determination on getting the best sound you can! hope to see more pics!

Thanks! Encouraging. As mentioned, this department of GS is great.

The pic is from yesterday. Now almost all traps are ready for installation. Will get back with a final pic and a measurement.

[unit7]

Today I managed to get half of the ceiling traps up (almost 4 sq metres of 8 total). While adjusting the height of them I was a little curious if the sound had changed so I put on one of my favs, the latest Eagles album. I wasn't sure first, but after I while I felt pretty confident that the bass sounded tighter. I mean, my old Gen 1030s is beginning to sound pretty awsome!

I also noticed that the sound again was more different when sitting under the new ceiling compared to 2 metres behind, so I just had to measure!..

Half the new ceiling is up and half of the 120-140Hz peak is gone (the green one is todays sweep). Will it disappear?... Stay tuned

[unit7]

Still some final cosmetical touches left. Ran out of cloth, but I just had to get that last unwrapped panel up (wrapped only with synthetic weave) temporarily, to be able to measure. Don't want to post a pic yet because of that, but - as mentioned - there's 2.4x3.6 metres of 12cm thick mineral wool hanging over my head right now

The new panels in the roof obviously has evened out everything even more.

It's nice to have that confirmed on the curve, but more important this last step really changed the sound around the sweetspot. A lot. I notice it when talking etc. And when listening to music it's clear that the bass/lo mid are more controlled now.

Talking about control I got curious about those waterfall plots and since I just payed for Fuzz Measure I'm now able to use that plugin. I'm not sure what's best to do, but I did three measurements (sweetspot, middle of room and rear). I guess that I can read/analyze them as good as anyone else, but I have no clue what would be good/bad, so I'd be very happy for any input from someone experienced.

When measuring from a distance I pointed the speaker straight out in the room. Just seemed logical with only one speaker playing the sweep, but please tell me if I was doing wrong.

And my 1030's still switched Treble switched to -4dB, which I did by ear at first, and that seems logical when watching the curves (I did a measure with treble at 0db at one time just to confirm that the treble got hyped. Sure did!)