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This week I was asked by a customer where they should hang their acoustic foam panels. Well it really depends on room usage. If it’s a mixing room then we know it’s a room where you want to hear everything. This particular customer wants to hear everything going on in the mix because he doesn’t want any surprises. He wants to put in what he wants to put in, the artist needs to have what they need in the song, the engineer needs to have what he needs in the song and no room sound is allowed. There’s no room for room sound in the mix, that’s a pretty good saying.

That said we can say with a high degree of safety that the front end of the room should be sound absorption treatment because our only other choice is diffusion and diffusers are like musical instruments, they have a character and a nature on their own. All you have to do is ask someone who’s never had diffusion and then give them some and then ask what they hear and they’ll understand what I mean immediately.

So we need to manage all the reflections from the room surfaces in the front end of the room. Now when I say front end of the room I mean all the distance from the front of the room to about a foot, foot and a half behind the monitoring or listening position. So that’s our domain, that’s the area that we’re going to be addressing with the treatment that he’s already built.

So fine tuning that will be a matter of me looking at your dimensions and if you get in a situation like that send me the information, as much as you can, distances from speakers to side walls, always the distances from the sound producing source or the energy-producing source, the speakers always the distances from that to the boundary of the room that’s the magical thing. In fact filling in this form is perfect:

How far are we away from the problem?

The speaker’s not the problem. The speaker does what it does and it does it very well today. Like we discussed before, it’s the room that’s the problem. So how far is the speaker away from the problem which is the room? Because those distances are critical. They determine how much absorption we use, not necessarily where we put it that’s pretty standard, but “How much we need?”, “What’s the rate and level of absorption?”, “What’s the pressure levels the user is using in the room?”. Maybe we need a little bit more than the foam in this distance between speaker and room?

So all these variables have to be taken into consideration. So sidewalls, front wall, how high off the floor, how far back is the listening position? We like to use a foot, foot and a half behind the listening position. So those are good guidelines and then always remember it’s a tuning process.

Once you get your acoustic foam panels and other treatments up and we can go through phone calls and Skype and all of that and photos are all really helpful. The more information you can give me the best. If the best way for me to do your room is get on an airplane and fly and sit in your room and then you and I spend a couple of days listening, we’ll get your room done, we’ll get it all figured out. Unfortunately I can’t do that with everyone, I wish I could you know. Time, energy, money all those things just don’t permit that. But that would be the best way.

The second best way is to give me as much information as you can. So fill out our form at that’s pretty thorough. Include photos, even photos with little arrows on, that show this distance or this distance. It’s one thing to see it in text but for me if I see it on the photo I can recognize immediately what’s going on.

Floor plans are good also

Floor plans are good for the dimensions and layout of the room but for the layout of the equipment it’s really nice if you just draw it out and measure the distances. It doesn’t have to be PowerPoint or anything fancy graphically. I do this every day so if I see something I don’t understand I’ll call you or send you an email so no worries about that. Just get me something to work with from the beginning and that was the reason we came up with the form on our website.

Always remember that this is a process. We can get you a great starting point, pretty close to where you need to be, say eighty percent, but the last twenty percent is a tuning process and the only way you’re going to realize how your room sounds after it’s treated is over time and exposure to different sources. Different music types, different pressure levels.

You may like it at 75 dB SPL. You might think it’s just beautiful but then you turn the gain up to eighty and that sixty-cycle room mode that’s on the short wall side now is in the mix. So you know we have to then treat that or work around it.

Every studio I ever go in, and almost every engineer I talk to in a control room or mixing room or some professional environment where there is music being produced, they’re working around some room acoustic problem. I see it every day. Well you know that if you’ve got to work around something you may not get it all the time. If it wasn’t there you wouldn’t have to worry about it and that’s the approach I like to take. Let’s get rid of it at the source so we don’t have to concentrate on “well I better be a little careful over here at eighty cycles because I got this pressure area in my room, that won’t like, you know more energy in the room so I better stay low”.

Yet the song calls for a little bit more energy. So you know you have this push and pull all the time and let’s get the room out of the way so you can concentrate on what you do best and that’s create music and record it, not have to worry about the room.

In Summary

I hope this discussion helped. So feel free to contact me directly at: 520 – 392 – 9486 MST or If you would like to learn more about room acoustics please sign up for my free videos and ebook by joining the mailing list here.

Thanks and speak soon

Dennis Foley

I am an acoustic engineer with over 30 years’ experience in the business. My technology has been used in Electric Lady Land Studios, Sony Music of New York, Cello Music and Films founded by Mark Levinson, and Saltmines Studios in Mesa, Arizona, along with hundreds of others.

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