Dr. AIX's POSTS — 28 February 2016

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Recently, I’ve been spending most of my free time writing, creating illustrations, and laying out Music and Audio: A User Guide To Better Sound. I can tell you that progress is painstaking but coming along. I’m pushing very hard to complete the project in time for the upcoming AXPONA Show, which will held in the middle of April. It’s going to be tight…especially as I haven’t started designing and preparing all of the elements that will go on the accompanying Blu-ray disc.

Today, I spent the whole day writing about cables. It just seemed so appropriate after the recent focus on the YouTube video featuring the AudioQuest HDMI cables. I’m not going to dig further into the topic right now but I can say that I’m continually amazed at what I read online and in other “high-end” audio books. However today, I’m going to talk about wiring of the new studios.

The new studios in the AIX Media Group building are coming along. All of the walls are up, there is insulation between the studs, the floors have been raised, and even a layer of soundboard has been attached to the walls. It’s time to figure out the wiring requirements of three individual spaces. The new tenant plans to have three rooms that can operate independently and in concert. The live central room is flanked by two recording and mixing spaces. And there’s a separate machine room in the corner of the largest 5.1 mixing room. So how does one figure out what types of cabling, how long they should be, and what sorts of terminating connectors should be on the ends? The answer is to methodically list all of the equipment that will be installed in the room and identify all of their associated inputs and outputs. It’s a laborious task but is critically important if you want to avoid mistakes and ensure everything is properly connected.

Additionally, one has to think about any future expansion and the flexibility that will be built into the wiring. In my main room, I have a number of panels strategically placed around the main studio, the isolation booth, and the machine rooms. These custom designed and fabricated panels have a combination of different connectors located on them. There’s also an analog and digital patch bay in the main studio that I can use to reconfigure the inputs and outputs of every piece of equipment available. The panels allow me to plug in a microphone and route it to the microphone preamps in an external rack, send line level signals to the headphone monitoring system, and connect the analog and digital inputs and outputs to the amplifiers and speakers.

All of the cabling comes from Belden, Canare, or Mogami depending on which what available when I went to Pacific Radio Exchange last week. The most expensive cable I purchased (the 24-pair cable to be used for microphones from the iso booth to the main room) was less than $4.00 per foot. In a 24-pair cable, the individual cables are not star quad and thus not effective against magnetic interference. I will be laying a variety of cables (microphone level, line level, MIDI, Ethernet CAT 5, HDMI, 12-gauge speaker, and Thunderbolt) in the troughs that run around and between each room. As long as I keep the main AC power leads away from the audio wiring, there shouldn’t be any induced noise.

Finally, I’ll be bringing all of the cabling through ELCO multi-pin connectors. These are large, rectangular connectors that have to be laboriously hand wired. They allow the engineer to quickly connect or disconnect an entire rack or machine with in one move. They use small gold contacts and are extremely reliable. The 24 microphone cables will show up on the side of the wall in the main room in a single ELCO connector and then to the back of the patchbay.

Laying out the wires and terminating each connector will take weeks. The smell of solder is going to floating through the space for a while.

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About Author

Dr. AIX

Mark Waldrep, aka Dr. AIX, has been producing and engineering music for over 40 years. He learned electronics as a teenager from his HAM radio father while learning to play the guitar. Mark received the first doctorate in music composition from UCLA in 1986 for a "binaural" electronic music composition. Other advanced degrees include an MS in computer science, an MFA/MA in music, BM in music and a BA in art. As an engineer and producer, Mark has worked on projects for the Rolling Stones, 311, Tool, KISS, Blink 182, Blues Traveler, Britney Spears, the San Francisco Symphony, The Dover Quartet, Willie Nelson, Paul Williams, The Allman Brothers, Bad Company and many more. Dr. Waldrep has been an innovator when it comes to multimedia and music. He created the first enhanced CDs in the 90s, the first DVD-Videos released in the U.S., the first web-connected DVD, the first DVD-Audio title, the first music Blu-ray disc and the first 3D Music Album. Additionally, he launched the first High Definition Music Download site in 2007 called iTrax.com. A frequency speaker at audio events, author of numerous articles, Dr. Waldrep is currently writing a book on the production and reproduction of high-end music called, "High-End Audio: A Practical Guide to Production and Playback". The book should be completed in the fall of 2013.

(26) Readers Comments

  1. Mark, in what circumstances would you use the star quad cables in your new studios?

    • All of the individual microphone cables are star quad. However, the multi pair snakes are not.

  2. Hi as always interesting to read and please let me know when your book will ready as I like to buy one copy for sure! It must be exciting to set up a new studio ?
    Regards Roland

    • I’ll keep you posted…it’s coming along.

  3. Always enjoy reading your blog! I have just a small rack of equipment, but have all the analog gear running through patchbays like yours in order to configure gear and I/O as desired. I have been unable to find digital patchbays though. You mention them today, I’m interested in AES/EBU, coaxial spdif and toslink. Any suggestions? Thanks! Looking forward to your book!

    • A digital patch bay is based on 75 Ohm video barrel connectors. You can’t do Toslink but the other two are pretty straight forward. I’ll write more about it in a future post.

  4. I hope you don’t mean cat 5 ethernet cable in the new studio since that is only “rated for 100mbs”, not the typical use case of 1gbs that needs cat 5e. I would hope you will slightly future proof your new setup with cat 6 or cat 6a if you have the physical space. 10gbs ethernet will be more affordable soon. The cable attributes do become a consideration with the higher frequencies and bandwidth but that is defined by standards organizations (not to be confused with marketing spin)

    You did say you were wiring thunderbolt so perhaps 10gb ethernet is less important to you.

    • The Ethernet cables are used for analog audio signals not digital feeds. Studios use them for musicians headphones cue systems.

  5. Please do not stray from what you set out to accomplish with the book. Do not rush to meet an arbitrary timeline nor focus on refuting the latest fad-of-the-month such as krypton cables or CD snake oil. You can refer to the marketing noise so we know what to look out for but please give us a fact based “users guide” to help us get “better sound” without building a multi-thousand dollar insulated home studio. I am looking forward to reading a book worthy of both your expertise and my kickstarter dollars.

    Thanks,
    John

    • Thanks John, I’m going to make sure that the book has the practical stuff…and I do regard cables as part of that.

  6. My comment isn’t about today’s topic per se, but you did mention the controversy regarding expensive digital cables. I too have a difficult time believing that ultra expensive cables can cause a significant improvement in sound, and I have not yet had an opportunity to hear the proported improvements, but I do hear differences in digital transport of the zeroes and ones on my own rather modest system.

    My PS Audio DAC permits three separate digital inputs from the transport and I have all three connected such that I can readily switch among them. One is coaxial using RCA connectors; one is XLR; and one is something called I2S. All three sound slightly different with the coax and XLR sounding closest to each other. The I2S connection evokes a significantly less “smeared” presentation. These differences have been consistent over the two years that I’ve listened to and tweaked the system. All of the cables have quality connectors but none would be considered very expensive.

    I hear the differences, but as a lowly research engineer I cannot begin to offer a plausible explanation.

    • You making an unfair comparison by switching between three different digital audio standards. You would need to switch between the same format using two different cables…like using two S/P DIF inputs and comparing. You will not find any differences is PS Audio is doing their job right.

  7. Don’t breath in to much lead fumes while doing all that soldering. 🙂
    And remember the all work and no play bit, you got a lot of irons in the pot right now LOL
    Take a break to relax a little, you no spring chicken any more.

    • I have fun with my dog and family everyday…but am working a lot too.

  8. Hello Mark
    Sounds like a fun project. Do you intend to use any isolation transformers or balanced power supplies, or are comfortable with DWP’s finest?. I did a quick check last night about purchasing hi- quality downloads from various artist and groups, and was disappointed with the lack of hi-rez options. People still offer mp3 as the number one download. Is it the cost of building a high quality studio or is there another reason that more studios do not record like you do?.

    • I’ve never used power conditioning in any of my studios or setup…including AXPONA type shows. If the power supplies of the equipment are properly designed, there is no need.

  9. Mark, just to let you know, if you need any advice or input on room sizes, shapes, or acoustic treatment, I’m always glad to help.

    • Thanks Ethan…I’ll be in touch.

  10. What, no power conditioning?

    I kid!

    Wondering which 24 pair you are getting for under $4.00 a foot, and if it’s tinned or not.

    Mogami 2936 has been my go to for 24 pair, but this runs me over $8 a foot, and I have used miles of Gotham cabling, but the cost has gone up quite a bit.

    Love Elco’s and wish the industry standard kept with them, but I guess they are too costly for consumer/prosumer.

    Thanks and have fun in the flux cloud,

    John

  11. The key to success in this type of project is to avoid obsolescence over time, to keep the design flexible enough to adapt to future changes without major alterations. One type of product that has proven useful are surface mounted raceways such as #3000, #4000, and #6000 Wiremold. Power MUST be kept in separate raceways from signal cables. It’s not just for isolation from noise, it’s the NEC code. There are also walkover type floor raceways that have a gradual slope on each side. I can’t think of any of the brands right now. These types of raceways have removable covers that you can snap off to easily add and remove wire at a future time. There have been many cases where I’ve had to cut the concrete floor to bury conduit underground where I was on the ground floor. This is expensive but there are times there’s no alternative. I’ve been involved in design and construction of over 100 video teleconference rooms, multipurpose rooms, and other rooms of this general type over the years.

    It is most fortunate that microphone signals which are so vulnerable to noise can be digitized right at the microphone now. This reduces the possibility of induced noise considerably. It is also convenient to have floor mounted boxes that have both power and signal capabilities around the floor where the top of the box is flush with the top of the floor. These types do require cutting concrete if you are on the ground floor, otherwise you can work inside of the ceiling below. It seems to me for a large recording console, there is no avoiding underfloor wiring unless you are prepared to accept surface mounted raceways.

    I’d also install a 100 amp sub panel in each studio so that additional circuits can be wired easily at a later date. I assume this is a commercial or industrial building with 120/208 volt wye service. A clean ground with a driven ground rod and wall mounted copper ground bar for signal grounds for each room is also not a bad idea. A lot depends on your budget.

    For separating walls I’d install a layer of “Quiet Rock” on each side under the sheet rock as well. This engineered material provides good isolation, about 10 times better than sheet rock.. Also caulk the floor and ceiling joints to reduce sound leakage between rooms. In the past I’ve used fiberglass batting, two layers of 5/8″ sheet rock, the outermost one being mounted on furring strips anchored to the first. I’ve also used acoustic doors and Armstrong painted nubby ceiling tiles, both very expensive.

    Do you have an acoustic consultant? What RT are you shooting for? Are you going to use diffusers, absorbers, or reflectors? I’ve used Armstrong Sound Soak quite a lot. If the room is too dead, that can be a difficult place for performers to work in. Also give careful consideration to the lighting layout.

    • Mark, the floors will be elevated with electrical and signal troughs separated. I’ve built a few studios over the years and am familiar with many of the items you bring up. I’m using the services of several studio architects and consultants. Thanks

      • I would have suggested a raised floor but I didn’t think it was in your budget Don’t forget the ramp (ADA code.)

        • We have raised the floors and will be bringing cables through roughs/

    • One practical example on caulk: two story studio (three story building, concrete/mason work, old with thick, thick walls, ex mining company office building), one large control room on the first floor with smaller sound booth, smaller control room and large recording room in the second floor.

      Contractor had caulked the floating floor to the stone walls, just 4-5mm seal between them. We took the measurements before and after it was fixed and the leak dropped extensively. It was almost a decade ago so can’t remember the values but it was significant, audible and of course measurable. So that i won’t lie a lot, it was in range of 10dB. Before any kind of high energy, bass, drums came thru on vocal recording sessions, afterwards it was not a problem up to 100dB in the upper room. Leakage from smaller room to big was not observed the same way; it had no such issues during construction, also the small room was as anechoic as possible, large room had movable walls and panels for tuning the acoustics and much more “air”, untreated surfaces in it.

      • Thanks very informative.

  12. At the end, when doing final measurements on signal, could you do “longest path” measurements? Would be nice to see the longest practical path that will be used in action, it’s SNR graph… I’ve done couple of these practical measurements for end-of-job QA, it’s really fascinating stuff. I could easily do that every day but alas, this is small country that hasn’t got a lot of systems to measure in any one year..

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