philosophies of different methods to treat small rooms

[jwl]

Greetings all,

I have some theoretical questions for the experts here. I would place myself in the catgory of "somewhat experienced and knowledgeable layman," I certainly am not an expert compared to many people who frequent this forum, though compared to most musicians, and many recording engineers, I am probably a bit more knowledgeable. And nearly all of my knowledge comes from extensive reading on this forum and others like it (Ethan's musicplayer forum, studiotips, RO, etc).

Anyway.

I've been thinking a lot about small room treatment. It seems there are some overlapping but competing approaches. For example, John, our gracious host, has his Wall Units treatment philosophy, which seems to be to "lower the reverb time of the room evenly across the frequency range" and includes very little absorption in the mid and high frequencies.

Another example is Ethan Winer's fantastic Acoustic Treatment and Design for Recording Studios and Listening Rooms, which can (with reasonable accuracy) be distilled to the following: add as many broadband absorbers in as many corners of the room as possible, and create a RFZ.

Another is the Studiotips Superchunks method, along with variations like Paul Woodlock's sick but inspiring build that singlehandedly ensures the economic survival of the rockwool manufacturers well into the 22nd century.

I think ultimately, these are just different approaches to the same problem. For example, in John's wall units, the side wall angled slot absorbers reflect the early reflections to the rear of the room, where they will be absorbed by the rear wall absorbers (in addition to absorbing sound within the bandwidth of the resonators). Whereas Ethan's approach will just absorb the sound right at the reflection point.

But I was wondering, can someone with more experience than I comment on the relative strengths and weakness of each approach? I'd love, for example, to hear what John might think of Ethan's approach, and vice versa, without triggering a flamewar. In my mind, this is fully in the realm of intellectual curiousity, and there is no room for egos spinning out of control.

In my mind, having a control room as dead as possible seems to be reasonable, that way when mixing any ambience that is heard is either in the original recording, or added by the mix engineer. Yet, so many acousticians caution against making the room sound too dead. Can anyone explain this a bit more?

[Ethan Winer]

JL,

My take is that all three approaches you mentioned are more alike than different. I agree the goal is for an even RT60 over a wide range of frequencies, though below about 300 Hz I'd aim for as little ringing (not really RT60) as possible. Of course, some people prefer their room to be more live generally, where others prefer more toward dead. I prefer more dead. But not totally dead.

Another factor with ideal target RT60 is the size of the room. I too would like to hear John's take on this because he has a much broader range of experience with genuine "pro quality" rooms.

I'll also share a small anecdote about the importance of a uniform RT60 versus frequency. When I built my current home studio, which is a large room (34' by 18' by 12' high), I had only bass traps in the wall-wall corners, and mid/high frequency absorption only in the front of the room at the "mixing" end. When I recorded string sections and other large "acoustic instrument" groups, all recordings that were not close-miked had a noticeable midrange "honk" for lack of a better word. Then it dawned on me that the problem was not an EQ-like "boost" but simply that those midrange frequencies were lingering longer. So the total energy in the room at those frequencies was higher than at other frequencies. Now that I've added a lot more broadband treatment all around the room, the sound is much more uniform both in the room and when recorded.

--Ethan

[jwl]

Thanks for the reply, Ethan.

I also realized I forgot to add a note of EXTREME GRATITUDE for the spirit of intellectual generosity that pervades this forum as well as the others I listed above. That's truly a breath of fresh air in this day of overzealous (to say the least) hoarding of information in the name of "protecting" one's intellectual property.

Though I am, as I say above, a fairly knowledgeable layman, the ONLY reason I am so is because people like Ethan Winer, John Sayers, Paul Woodlock, Eric Desart, Knightfly, Bob Gold, and so many others (sorry if I forgot you) are so willing to help out and share their knowledge, advice, and counsel.

The wider world has much to learn from the acoustics geeks here that has nothing to do with acoustics....

[AVare]

Interesting post. John's wall units are designed to absorb low frequencies while dispersing higher frequencies.

The superchunks are another acoustic version of what are referred her on RSD as bass traps, intended for corner placement to use the build up of all room modes at corners.

Ethan's traps are a nicely finished commercial product that again uses the corner build up of modes and has reduced HF absorption.

Each is a tool in the room design. Similar yet, ujnique.

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Andre