Fix Your Mix Often the problems with your mix isn’t your equipment or your ears – it’s your environment that needs a fix. by KeithHatschek
What do you do when you finish mixing a project and you take the reference CD upstairs to your home system or boom box and find that the balances in your mix sound completely different? Is it time to start over and remix? The problem could be that what you are hearing in your mixing room is not what is actually recorded on your tracks.
Bob Hodas AKA the Acoustical Doctor.
That’s the situation many studios find themselves in these days with the availability of powerful and affordable studio equipment and gear. The equipment provides the ability to create a professional-grade recording, but your environment may not be up to the task.
You might consider calling an acoustics professional. That’s what PSE did this month. Bob Hodas, AKA the Acoustical Doctor, has been tuning listening rooms and studios for over 15 years. A trusted consultant to large and small studios all around the world, one leading LA studio owner has dubbed him “the Michael Jordan of room tuning.”
The list of facilities the doctor has visited is vast and impressive, and includes Abbey Road Mastering Studios, Sony Music Entertainment Japan, Lucasfilm Ltd., and the personal studios of Stevie Wonder, Dave Pensado, Rob Cavallo, Ed Cherney, and Steely Dan’s Walter Becker… to name just a few.
Did you start out working at a studio?
No, in the early 70s, I was a drummer with a TEAC four-track, a few Sennheiser mics, and two mic preamps. No EQ, no compression, just mixing it live right to tape. I began to establish myself, and in 1978, I was hired by the Doobie Brothers to mix live sound. After two years on the road with them, I transitioned to a position at the Sausalito Record Plant.
It turned out that quite a few of the studio projects I was working on required me to travel far and wide to record, so I ended up working at too many studios to remember. Of course, at some places, you’d show up and have crap to work with. I become a fanatic about phase. I’d go into studio the day before our session would start and test everything: from the speaker phase, to the wiring, to all the outboard gear. At this time, there was usually a mix of microphones – some of them American, some European – with different XLR pin hot configurations, so you’d have to be careful or you’d be flipping a track out of phase just by using certain mics.
The testing was a form of self-defense, to be able to do my job properly. Pretty soon, I had a reputation as someone who would dig in to answer the question of why something didn’t sound right in any given studio. I’d wonder, “Why don’t these speakers sound good in here?” I wouldn’t give up until I solved the problem.
One day in the early ‘90s, I got a phone call from a friend who knew of my reputation. He had suggested the studio manager at Sandy Perlman’s Alpha and Omega Studio in San Francisco give me a call to come look at their room.
I headed over to the studio and went through it from top to bottom and made some suggestions that they felt improved the room’s accuracy. Rather than being hired to engineer a session, I was brought in to fine tune the performance of the room and signal path. That was my first paying gig as an acoustical and system consultant!
You use a pretty sophisticated computer analysis system today, how does it work?
I use the SIM 3 (Source Independent Measurement) system which was developed by John Meyer of Meyer Sound Labs.
+ Click image to view larger. The SIM 3 system at work. By comparing the input and output signals of each component in the system, the system's effect on the signal -- called the transfer function -- can be obtained and displayed as frequency, phase response and signal-to-noise ratio. (Image courtesy of Meyer Sound Labs)
I worked with John a while back when he was installing his large-scale, live sound studio systems. I was fascinated with how accurately we could measure a room’s performance and then tweak the systems to get the best results. I got hooked, and even though purchasing a SIM system cost $30,000, I decided I had to have one to use for my own work. In 1993, I took the plunge, figuring that it would be a sideline to my record engineering, using the SIM system to figure out how to improve control room listening environments.
How did you make the jump from engineering to acoustical analysis?
There was a memorable project not too long after I got the SIM system, where I was mixing a record for an artist who was more than a little bit neurotic. They would be listening to me mix and start commenting that the meter on the compressor looked like it was compressing too much. Pretty soon, they were interfering with the mix process so much, I had to tape over all the meters in the studio except the stereo bus so I could get some work done!
I guess that was the straw that broke the camel’s back. I realized I was getting depressed, so upon the completion of that project, I decided to take six months off and just feel around to try and get a few gigs doing SIM analysis for studios and get some rest. Then, I figured I would go back to making records.
I sent out a few flyers and pretty soon through word of mouth, I was getting calls on a regular basis. By the end of those six months, the light bulb went off over my head – I was up and running my new business.
Do you ever miss making records?
Bob measuring system response at Skywalker Sound, George Lucas's world famous studio.
The funny thing is, I actually have a much bigger impact on more records now, because I can help lots of people make their records sound better. I view my craft as an art form because no two rooms or situations are ever identical. Each job requires a new set of problem-solving skills. In its own way, it’s just as creative as mixing a record.
Walk us through a typical job.
There are usually two stages to the process. In the first visit, I’ll work to identify the acoustical problems using real-time SIM analysis. At the end of that process, which often includes moving the speakers into more accurate positions, I can usually recommend a few acoustical treatments to address the anomalies, often adding some well-placed absorption or diffusion, or occasionally removing some of those materials.
Then, after the new treatments are installed, I may come back and shoot the room one more time. At that stage, by adding some careful equalization, we’re really fine tuning the system performance and greatly increasing the imaging and depth the room is capable of.
Early on, I’ll usually get a call or an email saying “So and so recommended you, you just finished up at their studio.” We’ll start by emailing and speaking by phone and I’ll find out what sort of studio they have, ask them to send me some low resolution digital photos, a floor plan and an elevation of the room. We’ll also discuss the budget for my consultation, plus the fact that they may need to do some acoustical modifications to realize the benefits of what the SIM analysis uncovers.
At that point, I’ll have a pretty good idea of the situation and start mapping out some of the problems in my mind before I go there. However, until you actually hear the room, there’s no way you can predict exactly what it will sound like.
When I arrive, I’ll usually spend a full day on my first visit, starting by making some sound measurements and then rearranging things in the room, basically moving everything around a little bit, the speakers, the subwoofer, the desk, etc. I’ll take more measurements and see how the various placements affect the room’s sound. There’s usually one magic spot where the room is performing the best that it can.
One thing I’ve discovered with smaller project studios is that if the speakers are in the best spot for bass response, they are often not in the best spot for imaging. That’s why I’ll often ask the studio owner to bring in a subwoofer from their local dealer on the day I’m there so we can see if adding a sub will get more solid bass from their system and give them more flexibility on how their main speakers are placed. This often ends up giving them a bigger sweet spot for mixing. If the sub doesn’t make a big enough difference, they can return it to their dealer the next day.
Are there some common problems you encounter when you visit home or project studios?
There may be a range of problems to address: non-linear speaker performance, phase problems, room reflections, or distortion can all degrade system performance.
Acoustical problems are the other main issue. The SIM system can quickly pinpoint these and other problems in real time. These symptoms are most commonly described by studio owners wondering “why my mixes don’t seem to translate very well to the rest of the world.”
For example, one constant I hear is concern about bass performance and accuracy. I always measure before I make any comments, but often times, the studio owner will complain that the kick drum lacks punch, or there’s a big hole in the low frequencies, which when I shoot the room, will often be in the 100-125 Hz range.
Many times I’ll visit a room that has bass traps in the corners. There’s been a general assumption that “all corners are bad,” but I find that’s not always true. If I shoot the room with bass traps in the corners, and find that dreaded hole in the 100-125 Hz range, I’ll ask the studio owner, “How hard would it be to pull down those bass traps?” Many times after we’ve done that, BOOM, we’ll often find that 100 Hz is there and the kick drum is now very punchy.
So if you make a return trip, say a few months later after there have been some acoustical treatments applied, what do you do next?
I’ll start by measuring the room, and most often the changes will have improved the room’s performance a great deal. The studio owner will have secured some minimum phase parametric equalizers so we can really fine tune the room. That’s when the image, depth, and accuracy of what you are hearing is completely zeroed in. Sometimes, the room’s performance will be spot on without the EQ. Thank goodness!
However, if they are working in a living room, bedroom, or other space that wasn’t designed as a studio, it may be more cost effective to do a minimum of acoustical treatment and then apply EQ, rather than rebuilding the whole room. Most top professional studios use room EQ to optimize their sound.
How do you charge for your services?
For 80% of project studios, I can take care of what they need in one day. In the San Francisco Bay Area, I charge $1,000 per day, LA is $1,250. If a return visit is required, the rate for the next day goes down by half. For other west coast cities such as Seattle, Portland or LA, I charge $2,500 per day plus travel. If it’s east of the Rockies, I charge $3,000 per day plus travel.
The rate may vary some, for instance, I’m down in LA about a week each month. As a result, I’m often able to schedule 3 or 4 visits in a row so I can give each client a lower rate since I’ll be in their area all week. If I’m going to New York for a few days work, the travel costs will be shared among all those clients.
The whole process has to be considered as an investment in the studio by the owner. At the end of the day as a studio owner, you have to ask yourself, “What is going to allow me to advance my art the most? Is it a new reverb or exotic microphone, or is it knowing that what I am hearing in my room is accurate and that music sounds good in here?”
Often, I’ll get a call a few months after finishing up at a studio after the owner has had a well-known producer or engineer in for a day of overdubs and I’ll hear, “So and so really was impressed with what he was hearing while he was working here.” That’s the payoff, people who know good sound will be comfortable working at your studio and are more likely to come back.
Story Links Bob Hodas Acoustical Analysis – www.bobhodas.com
Find articles written by Bob by searching www.mixonline.com
A six-part series on speaker placement for home listening rooms can be found on Modern Home Theater’s web site. Look near the bottom of this page: www.modernhometheater.com/howto/
A look at what some of the common studio problems look like on the SIM system can be seen at www.bobhodas.com/process.html
For a little history and a look at the power of the SIM 3system Bob uses, visit www.meyersound.com/sim3/
