Measuring and Treating a Home Studio Using FuzzMeasure Pro: Part 1

The Project

I’ve been interested in playing and recording music for a large part of my life. When I was younger, I used to play the drums in my school’s (orchestral) band, and then I replaced my drum set with a keyboard a few years after that to get deeper into electronic music production. Just over two years ago, I started learning to play the guitar, which has brought a lot of that old musical experience rushing back.

Recently, I relocated my office to the basement, so it is no longer exposed to the rest of the house. As a result, I have a great deal of freedom to set my office up to optimize it for playing and recording music. For starters, I no longer have to worry about the aesthetic impact of hanging acoustic panels on the walls and ceiling. That said, I am not interested in making my office ugly, either—I work here full-time.

Goals

Playing Guitar

To my ears, the room sounds pretty good when I'm playing music in my office. Unfortunately, there is a pronounced bass bump that I hear while playing my electric guitars amplified:

Obviously, the bass bump must be helping my speakers, which don't have much of a low-end of their own. On the other hand, my guitar amplifier has a 12" speaker, and I have to keep the bass turned way down in this room.

Reduced Flutter Echo

There’s also a definite flutter echo I hear in the room when I clap my hands, which is likely contributing to the increased fatigue I get while playing my guitars amplified (compared to my old office location):

Recording

I am also planning to get a modest drum kit set up in my office, so I’d like them to sound decent when recorded using overhead microphones. Reducing reflections and trapping bass around the room will likely go a long way to ensure that.

Room Layout

The office is not a perfect square, or a rectangle for that matter. From an acoustics standpoint, that can be a good thing.

Note that the sump pump cover is shown in the floor dimensions, but it doesn’t extend to the ceiling. It’s only 23” tall, and serves as a nice extension to my desk space.

Here are some images that illustrate the current state of my room:

Ideally, I would like to place my drums where my acoustic guitar is located, but there isn't enough space for them there. Instead, the drums will have to go where my guest chair is currently located.

Acoustic Measurements: Untreated

In this section I would like to present various graphs of some measurements I took of the space. The microphone was placed at approximately ear level, where my head would normally be while I'm sitting at my desk. Each measurement was repeated for the left, and then the right channel. The graphs are all presented in that order—with the left measurement shown on the left-hand side.

Low-Frequency Magnitude Response Graphs

These graphs illustrate that there is a large null at just over 200Hz—this should go away with a moderate application of bass traps around the room. However, with this view alone, we can't see any peaks very clearly. It's hard to tell what is part of the speaker's natural response, and what is part of the room's influence. The Waterfall should help give a better picture…

Low-Frequency Waterfall Graphs

As is expected, there are some clear peaks visible in the waterfall. Specifically, just on either side of the null we identified above, there are some narrow peaks that last approximately 200ms. These issues should also go away with sufficient bass trapping.

Note that the presence of lasting “ridges” in the waterfall does not necessarily indicate a problem. What we are trying to avoid, in particular, are narrow ridges that last a few hundred milliseconds. That is the tell-tale sign of a room mode being excited, where a sound wave with a specific frequency is bouncing around your room for a long period of time.

Full-Range Magnitude Response Graphs

While they look quite messy, these graphs demonstrate an effect known as combing. When sound waves reflect all around the room, many of them cancel each other out, creating a repeating pattern of nulls through the frequency response graph. This pattern resembles a hair comb, which is where the term originates.

You could try and pick out the individual nulls, estimate the specific frequencies that are troublesome, and try to optimize speaker placement to reduce the effect—but that would be insane. Instead, the purpose of these graphs are to illustrate that the combing effect is present. When treatments are applied, the hope is to reduce the combing that is visible in the full-range magnitude response graph.

Reverberation Time Graphs

There isn't anything too surprising about these graphs, as they correspond with what we're seeing in the waterfall. If nothing else, they serve as yet another data point we can use for comparison later on.

The reverberation time in this room ranges from about 600ms in the worst case, down to about 230ms in the best case. The room is fairly live, which wouldn't be great for monitoring/mixing, but is OK for recording.

Envelope Time Curve (ETC) Graphs

In FuzzMeasure 3.2, the Energy Time Curve graph was added to show a more representative display of reflections in the time domain. As you can see in these graphs, there is just under 1ms (0.69ms, to be exact) between the primary peak, and the first reflection. The same reflection point is visible in both graphs.

With a simple calculation, I determined that this corresponds to a surface that is approximately 3.56" away from the source. That is, my desktop is supplying the first reflection point.

Treatment Plans

Because I would like to maximize the treatments I can get for my dollar, I will likely be purchasing a mixture of RealTraps BareTraps to scatter around the space. By sticking to a tight budget, I hope to demonstrate that you can see some real improvements without breaking the bank.

The idea is to get as many low- and high-frequency absorbers into the space as possible. Unfortunately, until the drum kit is in place, this planning cannot be finalized.

The budget goal for this project is to spend less than $2000. Ideally I'd like to achieve my performance goals by spending only $1000—that'd be a total of 10 BareTraps split between high- and low-frequency absorption tasks. $2000 is definitely a lot of money, but the improvement should certainly be far greater than blowing that $2000 on a fancy amplifier, or DAC, or magical interconnects for my speakers.

I believe that I will be able to see measurable improvements with 10 traps placed around the room. If I were to bump that up to 15 or 20 traps, I'm not even sure that I'd have room for them all.

In the next installment, I will discuss proposed placement information, and costs for the final treatment list.