We are extremely pleased to bring you an interview with one of the industry’s most respected mastering engineers. Bob Ludwig has won the prestigious Mix Magazine TEC award seven times. He was the first person to be honored with the Les Paul Award for “...individuals who have set the highest standards of excellence in recording and sound production over a period of many years.” His studio, Gateway Mastering, has won the TEC award every year it has been eligible. Bob and the studio are nominated once again this year.

Gateway has mastered many Grammy award winning albums and their Web site client list includes just about every artist you can think of. Anyone who visits Gateway Mastering Studios is amazed at the sound of the mastering room, the bleeding-edge technology, the knowledgeable staff, and the warmth, caring, and incomparable expertise of Bob Ludwig. Gateway is leading the way again with 96kHz/24 bit, DVD authoring, and home theater technologies.

RPG
Speaking for music lovers everywhere, thanks for bringing us so much wonderful music. Can you summarize your years in New York and what led you to consider building your dream facility in Portland, Maine?

Bob Ludwig
Thank you, Peter, for saying that. I’m lucky enough to have, what is for me, the best job in the world. I was finishing up my Masters degree at the Eastman School of Music in Rochester when Phil Ramone came up to teach the first Recording Workshop ever held at the school. I was Phil’s assistant as I was the only student working in the recording department. I left to go work with Phil at A&R Recording where my career started. I learned the art of disk mastering there. I began doing work for groups like The Band with Music From Big Pink, Peter, Paul, & Mary, Jimi Hendrix, and Dionne Warwick singing the famous Burt Bachrach and Hal David hits. I learned how to hear from Julie Klages (Enoch Light’s daughter) and the production team of Lieber and Stoller.

After a few years I left A&R to go with a brand new company who had the very latest Neumann solid state cutting equipment and all European Telefunken and Studer machines. It was Sterling Sound. With Lee Hulko as President, they soon became one of the major mastering facilities of the world. At one point, Sterling Sound and Masterdisk were owned by the same public company. After seven years at Sterling I left and joined Masterdisk and became Vice President and Chief Engineer there. I worked there a long time and did lots of albums including Springsteen’s “Born In the USA” which was the first commercially pressed CD to be made in America—before that all CDs were either made in Japan or in Europe.

Several factors led me to building my own business. Masterdisk is owned primarily by an investment group and it became clear to me that no matter how many years I remained there I would never be in charge of my own destiny. Also, the quality of life in New York was getting to me: my car had been broken into 7 times and was stolen from the gated, attended parking lot across the street! My folks have lived in Maine for 30 years and I had fallen in love with the State while visiting them. It seemed time to jump off the cliff, start my own studio and take control of whatever would happen. I spent quite a few years planning it with Dan Crewe who was my original business partner. He made all of it possible by arranging all the financing (six loans!) and keeping me on track when the going got rough at times.

RPG
It has been about 5 years since Gateway Mastering Studios opened. Has the move and the new facility been everything you had hoped for?

Bob Ludwig
Beyond my wildest dreams! We opened our studio doors January 8, 1993. Our first session was from LA and we didn’t even have my big studio built yet, we were working out of a temporary room. They still wanted to come. We told them we didn’t have furniture yet, they still came! It was like opening the doors and having a Mac Truck come through the door. I was hoping to relax a little up here in Maine, but I have been busier than I ever was in NY and that is saying a lot. Ironically we have had more people attend sessions here than I did in NY which was a big surprise. People have come from all over the world.

I had always wanted to have as perfect a mastering room as was possible. Working in NY high rise buildings precluded having high ceilings that an acoustically ideal room demands. Here in Maine, with the help of Scott McConville, my Director of Engineering, I was able to finally get a room built that was as close to ideal as I could get.

RPG
Since mastering is the final creative step in the record making process, you have a great deal of responsibility to capture art with technology, as your slogan so wonderfully states. What in your background prepared you to do what you do so well?

Bob Ludwig
I’ve been heavily into music since I can remember. I am a musician first and an engineer second. I used to be the Principal Trumpet player with the Utica Symphony so I know what it is like to be a performer and how important it can be to accurately capture every nuance in a recording. I have been a Producer, so I can appreciate first hand what is going on with a client who walks in my door to finish up their record. I know the politics and the agony they have faced trying to bring their artistic vision to their recording. I appreciate the sweat that has gone into making each bar of music. I also know a fair amount about engineering. I’ve been in the Audio Engineering Society since 1968 and I was fortunate enough to work with Phil Ramone and the amazing engineering maintenance staff they had there at the time. There has never been an assembly of people as existed at A&R at the time. Each maintenance person went on to become President of his own business. People like Bill Windsor, Larry Dahlstrom, Aaron Baron, and Eric Small to name a few. It was a marvelous apprenticeship.

RPG
I know you do your best to get what you hear in your room out to the public. The CD has imposed sonic constraints on us for 15 years now. What excites you the most about the current and future music and home theater delivery systems?

Bob Ludwig
Almost 2 years ago when I first heard that the DVD Video was going to support recording at 96kHz/24 bit I got very excited. We were (to my knowledge) the first mastering studio in America to have 96kHz/24 bit recording ability. Some of our 96kHz gear has serial number 1!! We made the first CD ever done on a high sample rate Sonic Solutions Workstation. All the complaints about digital being inferior in sound to analog fall away when listening to 96kHz/24 bit recordings. Although we got into DVD in a big way as a result of 96kHz recordings, it has been the 5.1 surround recordings that have gotten our clients really excited!

I’m old enough to have seen Quadraphonic 4 channel sound come and go, but 5.1 is here to stay. It is a whole new aesthetic and I couldn’t be more excited about it. The new DVD Audio standard uses the lossless compression scheme invented by Meridian in the UK. This system will allow us to not only have 96kHz surround channels but 192kHz as well! Again, there is no loss of the music as is true of Dolby Digital and DTS.

RPG
There is a lot of emphasis on electronic technology and rightly so with the incredible digital advances that are available in our industry. However, sound must eventually travel the analog path from loudspeaker to listener. I know you have gone to great lengths to create an ideal acoustical listening environment to do your work. When or what event made you realize the importance of the acoustics of the room you work in?

Bob Ludwig
When I first started mastering at A&R and Sterling Sound, I was always frustrated by never having a sonic standard I could trust. I was always checking out what I had done on many systems and making a mental average of what I was hearing. At A&R I started on Altec 604E speakers which were the standard of the industry. One never had the proper amount of mid-range in the sound unless the speaker started hurting you! Low bass . . . what was that?

At Sterling we started with KLH5 bookshelf speakers which we considered a high-average home system. Audiophile speaker systems began to be used by mastering engineers. I was the first to use B&W loudspeakers at Sterling. It was the model with electrostatic mids and top with a bass woofer crossover. It sounded pretty good, but one couldn’t get much dynamic range out of it. I recall Eddie Kramer tried using them at Electric Lady and the heavily acoustically damped room just soaked up the sound so it was always clipping. My room at A&R was a large closet. Our rooms at Sterling and Masterdisk were semi-living room oriented in an attempt to approximate what things might be like in a home environment.

RPG
The Project Studio has evolved with an emphasis on electronic equipment. Acoustics is often ignored. What advice would you give to someone spending countless hours making sonic judgements in a room with an unknown acoustic signature?

Bob Ludwig
I’d tell them to stop wasting their time! Knowing a room’s acoustics is crucial to making the final determinations one needs to do a proper mastering job. What are the resonance frequencies of the length of the room, of the width, or the height? If the room is too square one will get the same resonances from more than one mode at once causing intolerable listening conditions. The acoustics of the room and the speakers are an inseparable marriage. One can’t listen to one without the other. There is no point in having super accurate, high resolution speakers in a room whose resonance and lack of control of the first reflections spoil every note one hears. If the room isn’t right, the speakers can never be right either!

RPG
We use the slogan “Listen To the Music, Not the Room!” to try to stress the importance of transferability. Since one of your goals is to reproduce the artist’s vision in as many different listening environments as possible, what acoustical steps have you taken in the design of the Mastering Room to accomplish this?

Bob Ludwig
Fortunately, I have found that music that sounds correct on a very high resolution speaker system in a room with excellent acoustics tends to sound good on the widest range of systems.

Our room is based on acoustical ratios that allow the resonances of the width, length, and height to not interfere with each other until they are high in the frequency spectrum where they are not noticeable. The room is 30 feet long in order to be able to reproduce low frequencies without problems. This then dictates a ceiling near 16 feet high as a minimum, again to keep resonances from interfering with each other. Same with the width. The walls have seven layers of sheet rock—enough to build many condos—that are glued and screwed together with an air space between some layers. The floor is acoustically floated along with the ceilings and walls to prevent any outside sound from getting into the studio and to prevent any sound from within the studio from bothering our neighbors or our other studios.

The sound reflections near the speakers are somewhat absorbed while the rear of the room contains the world’s first third generation Diffractal®. It’s purpose is to keep the listening area somewhat live sounding so the room sounds natural, yet no one particular sound frequency emanating from the speakers is reflected back into the sound field from the rear wall to cancel out meaningful music. Flutterfree® panels are angled high on the ceiling to steer sound from the speakers into the Diffractal®. The angles of the first reflection are carefully calculated and angled absorption is used to control this. If the first reflection is not controlled, it will arrive at the listener’s ear only a few milliseconds after the original sound and with almost the same amplitude as the original. It greatly smears the sound.

A few years ago Q-Sound was in vogue. It was a system to generate sounds outside of the speaker boundaries. It could take mid-range frequencies and make it seem as though there were surround speakers set up. When the original investors in the system showed it to me it was explained that it only worked on near-field speakers mounted away from any walls. It didn’t work on their (famous LA studio) big speakers. Well, Q-Sounds works just fine on my big speakers a great distance from them! Why? Q-Sound depends on accurate phase relationships reaching the listener’s ear to create the surround effect. My room, fortunately, maintains these accurate phase relationships all the way back to the listening position.

RPG
Many studios are now trying to decide how to configure their rooms for the discrete digital surround formats. The International Telecommunications Union has proposed a configuration with the left and right front speakers 30 degrees and the rear surrounds 110 degrees with respect to the forward direction. Do you use this configuration or have you found something that works better for you?

Bob Ludwig
I think that studios that demand speakers built into a wall soffit are going to be in trouble! For the present, every major recording organization around the world—Sony, Philips, NHK, Denon, etc.—all use the ITU specification. Tom Holman, the man responsible for 5.1 surround via Lucas Films told me that there are lots of papers and experiments that show between 30 and 35 degrees for the front speakers is ideal and the same with the rear. Unfortunately, many engineers like to work with speakers placed in an equilateral triangle in the front and an equilateral triangle in the rear. They design their mixes to be best this way and insist on it being like this on playback. Better allow for both! One advantage of the 110 degree rear is that it is closer to the average apartment dwellers surround set up than the equilateral rears.

The THX surround standard suggests rear speakers that are bipolar, somewhat nondirectional and located up above the listener’s ear, as in a theatre. The center speaker is often a much smaller speaker than the left and right full range speakers in order to fit on top of a TV and is used mostly for dialog. The subwoofer channel is limited to low frequencies around 150 Hz (I think) and lower. Music only 5.1 surround calls for five equal full range speakers. With DTS the subwoofer channel is actually full range. The speakers are supposed to be the normal directional speakers pointed at you from the rear. So studios who plan to be both music-only and THX ready must be able to move those rear speakers into 3 different locations! Or get to know the room and make accommodations for them!

RPG
Since your mastering room was designed and built before the current 5.1 surround formats became available, how have you adapted it to this new format?

Bob Ludwig
Well, when the room is set up for 5.1 we have to put a sign on the studio door to open it very slowly as there is a rear speaker within range of the door if it were to swing all the way open! We actually did plan for THX surround, and there is in fact room on our rear walls for a bipolar high mounted speaker. So far 90% of our 5.1 work has been music-only surround. And the DVDs we have mastered have been ones that were mixed as though they were music-only! The high spot on the wall remains bare! When I first set up the 5.1 system in my room, I expected that the rear speakers would need more absorption near them, but they sound just fine the way they are. I am going to continue experimenting, and I need to buy some Abffusors® from RPG® to do this!

I might add that our main stereo speakers weigh over 700 lbs. each! We have special $250 casters mounted on them so they can come off their spikes and be rolled out to bring in the five Eggleston Works Andras and the wonderful M&K subwoofer. If you think all subwoofers are the same, you have an unpleasant surprise coming! We use Cello Duet amplifiers and Transparent Audio Speaker cables for the surrounds. Our stereo amps are bridged Cello’s which cost $44,000 a pair last time I priced them. We couldn’t afford that for the surrounds!

RPG
5.1 DVD multichannel music and home theater are playing an expanded role in your future plans. What was the acoustical design philosophy behind your new home theater studio?

Bob Ludwig
We needed a Quality Control room for the DVD Authoring we do, so we built a great home theatre studio with a line-quadrupled projector and a professional screen. We use a Meridian controller for the 5.1 Dolby Digital, the DTS, and it will even be DSD compliant. We knew we did not have the room or budget to build a super room like my mastering studio so we did the best with what we were given. We use RPG® Skylines® for the ceiling with a special painting technique that makes it look spectacular. The rear wall is also all Skyline® with acoustical fabric covering it so it merely looks like a normal rear wall. The sidewalls are covered from floor to ceiling with RPG’s new flat diffusor. It is based on a novel two dimensional binary amplitude grating, instead of the reflection phase grating used in their original products. They call this the binary amplitude diffusor or BAD™ Panel and it is also upholstered in fabric. As of this writing we are still about a week away from the room being commissioned. As I haven’t heard the room yet, it may need some additional RPG® items installed unless we got lucky.

RPG
In addition to acoustical design, listener and loudspeaker placement are critical to optimally couple with the room, thus minimizing the modal emphasis and speaker/boundary interference. I know you are sensitive to these issues. RPG® has developed the first multidimensional optimization program to address these problems. How did RPG’s speaker placement suggestions work out in your mastering room?

Bob Ludwig
Well, the speakers in our mastering room were placed as suggested by an early version of RPG’s Room Optimizer™ software program. In order to make sure that the sound from the speakers was reaching us through the air before reaching our feet through the studio floor (sound travels faster through a studio floor than through the air), we constructed concrete pads that are isolated from our floating floor. These concrete pads go down to the bedrock that is not far beneath us. To provide some room for tweaking the loudspeaker positions suggested by the Room Optimizer™, we added an additional six inches of concrete around the perimeter of the Duntechs.

When we finished building the studio, we placed the Duntech 2001 Soveriegn speakers exactly as Dr. D’Antonio’s Room Optimizer™ suggested as a starting point. We opened the monitor pot and the sound was instantly amazing. To be sure, we tried every other speaker position we could and to our delight the location the multidimensional optimization program suggested was the best possible position!

Your mileage may vary of course, but perhaps because the construction of our room with the very thick solid walls made the acoustic dimensions of the room very stable, our positioning was exact! Fortunately, we are now trying out a new super speaker made by Eggleston Works in Memphis Tennessee. It is a very large speaker with 23 best quality drivers in it. They weigh over 700 lbs. each, so the larger concrete platform has come in very handy for this new monitor standard!

RPG
Based on your experience with RPG, what would you tell someone who is evaluating the various acoustical products available in our industry?

Bob Ludwig
RPG® makes the acoustic sound tools used by professionals. These acoustic controls were invented by the scientist who started it all. I have mastered with RPG® products for the past 12 years and consider them an important ingredient in obtaining the sound I am looking for. Through the years, RPG® has consistently been very cooperative and has helped us with many of our acoustical problems. They are as knowledgeable as they come and you don’t waste time and money trying things that don’t work.