RTA Software for measuring room acoustics

[LaceSensor]

Hello, I'll be moving into a new house with my first recording/studio space. I've already got a Dayton reference mic and true RTA software. I've seen in some books RTAs which show waterfall plots for freq. over time over level. I do not believe trueRTA has this feature but I'd like to measure which bass freq. are propagating longer over time.

What software are you home studio engineers using to measure your rooms acoustics?


More details:

I'll be in a concrete basement, large room, rectangular. The same space will be used for mixing and recording. I've got a decent budget for bass traps and such.

 

[bouldersoundguy]

Technically, what you want is not a "real time" analyzer but a time sensitive analyzer. I use REW.

 

[Folkcafe]

REW (Room EQ Wizard)

The approach I took was used John Brandt's Excel spreadsheet to model and used REW to verify all the room modes with the room empty using this RPG chart. You'll get confirmation on where your problem frequencies are. From there, you can calculate how deep and how much it will take to get them under control.

 

[LaceSensor]

REW (Room EQ Wizard)

The approach I took was used John Brandt's Excel spreadsheet to model and used REW to verify all the room modes with the room empty using this RPG chart. You'll get confirmation on where your problem frequencies are. From there, you can calculate how deep and how much it will take to get them under control.

View attachment 119112

Is room empty an important detail? Since the room will be empty when I move in 2 weeks, I have an opportunity to measure completely empty. Otherwise I would go ahead and start putting moving boxes into this room before unpacking and then finally metering. Worth the time to do this with an empty room?

I see this excel spreadsheet is split into control/tracking rooms. If my room will be dual purpose which direction is best to lean into?

 

[Folkcafe]

The idea of measuring empty is to verify theoretical. It will likely be off slightly due to variances in construction or physical measurements but the idea is to check that you've not made a mistake in calculation. You fill it up, you won't know. The process is pretty simple. Place a speaker in the corner (represented by the circle in the rear left) and measure sweeps looking for mode peaks in the listed mic positions and compare from the spreadsheet.

Dual purpose room, you'll have to decide how live or dead you want it for recording while striking a good balance for monitoring while mixing. In my opinion, getting the bass tamed is the biggest challenge but also brings the greatest pay off. I got the bottom end in my room +/- 3db all the way down to my lowest mode. The changing result from my old treatment was more articulate bass rather than mud. Makes mixing easier. While I have a two room studio, I still do a fair amount of tracking in the control room. I've kept it fairly live. I've a full wall bass trap behind mix position 2ft deep, 12 inch thick cloud that covers most of the ceiling, 2ft thick corner traps in front and various panels filling in the front. I've left the two side walls pretty sparse as to treatment and it adds enough ambiance as to make listening and recording sound pretty natural.

 

[LaceSensor]

The idea of measuring empty is to verify theoretical. It will likely be off slightly due to variances in construction or physical measurements but the idea is to check that you've not made a mistake in calculation. You fill it up, you won't know. The process is pretty simple. Place a speaker in the corner (represented by the circle in the rear left) and measure sweeps looking for mode peaks in the listed mic positions and compare from the spreadsheet.

Dual purpose room, you'll have to decide how live or dead you want it for recording while striking a good balance for monitoring while mixing. In my opinion, getting the bass tamed is the biggest challenge but also brings the greatest pay off. I got the bottom end in my room +/- 3db all the way down to my lowest mode. The changing result from my old treatment was more articulate bass rather than mud. Makes mixing easier. While I have a two room studio, I still do a fair amount of tracking in the control room. I've kept it fairly live. I've a full wall bass trap behind mix position 2ft deep, 12 inch thick cloud that covers most of the ceiling, 2ft thick corner traps in front and various panels filling in the front. I've left the two side walls pretty sparse as to treatment and it adds enough ambiance as to make listening and recording sound pretty natural.

This is very helpful. My thinking is to tackle the bass first and then apply dampening/diffusion as needed or as a secondary step.

I'm renting so not able to make any structural or permanent acoustic mods.

What corner speaker are you using which is getting you down into sub 40hz range? I'll have a pair of HS8s and about purchase a pair of Yamaha PA mains for band rehearsals. Would either of these work for this purpose or should I use a sealed subwoofer?

 

[Folkcafe]

This is very helpful. My thinking is to tackle the bass first and then apply dampening/diffusion as needed or as a secondary step.

I'm renting so not able to make any structural or permanent acoustic mods.

What corner speaker are you using which is getting you down into sub 40hz range? I'll have a pair of HS8s and about purchase a pair of Yamaha PA mains for band rehearsals. Would either of these work for this purpose or should I use a sealed subwoofer?

I never really liked basement studios so when I built my house, I went up rather than down. Living out in the middle of nowhere meant I didn't have to have a lot of mass so I could build with low end energy escaping (cows next door never seemed to mind). Also was fortunate that my issues both measured and actual were not in the sub range.

I was using a Tannor 15 inch sub with a couple pairs of KRK and struggled with getting clarity in bass above 80 as the enclosed chart will show. Also if you get my user name, sub bass wasn't my thing. Even still, 125 was a real pain to deal with and why I have a full ceiling cloud. I used a JBL 305mkii to measure initially and played with the sub a bit. Because of the porting in the 305, it has a resonate bass peak that made things confusing a bit at first. I jotted down a couple numbers with the Tannoy and quickly moved on as sub 40 wasn't my issue. Of note, actual was pretty close to this chart (got my numbers somewhere but it's late).

The handy thing with the spreadsheet is that it gives you a baseline of what your challenges are likely going to be and John's also lets you know how much bass trapping your going to need. From there you can decide what is possible given your particular circumstances and budget. Lots of other people have approaches that are different. For many years I had some treatment which was better than none but far less than ideal. I spent a lot of time with headphones and listening to mixes outside the control room.

One other thing to note, you'll notice the modes are relative, as in 40 & 80. This is typical. If you address the lower, the higher often tends to take care of itself to some extent.