Building a 5.1 Setup

[soundeditor76]

Any 5.1 speaker setup that has full range LCR is going to work fine. The key is making sure that your room is tuned and pinked at a good listenable SPL. I said this in another post, but the MOTU 828 has a DSP mixer with 7 band parametric EQs, if you get an RTA, or an RTA application with a calibrated test mic, you could EQ out most of the problem areas in your room. Doing this, and referencing at the proper SPL you will help you translate properly.

[JesseG]

Would you choose the MOTU over the Profire?

[nzl62]

I would. I am in the same boat and debating what steps to take. I think I am going to get an RME UFX but having researched a while, the Motu 828 and the bigger brother (896?)
review better for driver compatibility and reliability.
In Presonus's favour is the price and that you can get a pretty cool control room controller that has the 6track monitor solos/mutes and a master.

I bought a Martinsound multimax off ebay so I am less concerned about having a master volume now and more concerned about quality/reliability

[djmukilteo]

Originally Posted by soundeditor76

Any 5.1 speaker setup that has full range LCR is going to work fine. The key is making sure that your room is tuned and pinked at a good listenable SPL. I said this in another post, but the MOTU 828 has a DSP mixer with 7 band parametric EQs, if you get an RTA, or an RTA application with a calibrated test mic, you could EQ out most of the problem areas in your room. Doing this, and referencing at the proper SPL you will help you translate properly.

I agree with the above post.
Any 5.1 or 7.1 system has to start with and focus on the monitors and room first.
Most DAW's (Cubase, PT etc..) will give you the 5.1 or 7.1 channels you need and any interface with enough outputs will do the job.
A good monitor controller/console would also help with mixing and workflow I'm sure some people could work in the DAW though.
But without a good room and monitors to mix with I think your just going to be lost in a mash of sound.

[DaVogi]

you'll need the cptk for surround in pro tools... that pushes the price up to a region where you could consider an hd native with omni interface which will save you expenses in a surround monitor controller which you would need with most other interfaces.

[soundeditor76]

MOTU 828 has a surround monitor built in, you can also map a hui compatible knob to it. The most important thing is to be able to fix EQ problems in your room, if your mixing for film you want to roll off some of the highs with the EQ to match the X-curve. The MOTU has a 7 band parametric internal DSP EQ per channel. If you bought separate hardware EQ's per channel it would be well over $2k as opposed to $600.00.

[minister]

Originally Posted by soundeditor76

The most important thing is to be able to fix EQ problems in your room,

More important is to fix the room physically in the layout and treatment. If you still have problems, you should be moving panels, diffusers, speakers and furniture around before you get into to any "EQ fixes". Fix problems in the time domain in the time domain before you try to fix them in the frequency domain.

Originally Posted by soundeditor76

if your mixing for film you want to roll off some of the highs with the EQ to match the X-curve.

He is just looking at investing in 5.1, do you think his room is large enough to warrant the X-Curve? Many people seem to throw this idea around because the read that Dub Stages do it. It is intended for Theatrical-sized spaces, not small control rooms! The Curve was established to replace the Academy Curve and to render the room and it's cinema speakers similar to a set of nearfields playing closer to the console -- like they would be in a small room..... The Modified Curve is intended for smaller that Theater-sized rooms, but still pretty large ones, certainly larger than the average sized audio post room. Doing the X-Curve in a small room is a bad idea. Furthermore, getting an RTA and Mics and and trying to achieve the curve is not easy and you really have to know what you are doing.

[soundeditor76]

Why is doing a modified x-curve in a smaller room a bad idea? Dolby just came out 2 weeks ago and tuned a small room for a show im working on, matching the eq frequency response of the room to the rta x-curve overlay. Also it really isnt very difficult to apply the x-curve in a room, I can EQ mine in about an hour, so can Dolby.

[Smallbudgetguru]

Whats your definition of small?

X curve generally is not for small rooms

[minister]

Originally Posted by Smallbudgetguru

Whats your definition of small?

X curve generally is not for small rooms

The Modified X-Curve is mentioned by Dolby for rooms smaller than 5300 cubic feet.

Dolby comes out here and tunes my room pretty quickly and I have watched him on several occasions. It is not all that hard. Set up mics, Pink through the system, and he adjusts the Ashley EQ's via SMAART. Would I trust myself to do it? Not until I had done it several times and tested out the translation afterward and carefully noted issues and differences. I'd rather not do it.

However, the original poster just wants to figure out how to even get the gear for 5.1 setup. He has enough to worry about with just this. And, to be honest, if he is in a room that has an 8 or 9 foot ceiling and is 12 feet by 14 feet, (or something like that) and he is 3 or 4 feet from his speakers I think it is a complete waste of time.

Furthermore, he has to have a way to easily bypass it for everything else other than "film mixes" or "film editorial" that is destined for a Dub Stage.

My experience in my rooms, and others' rooms, is that translation from a small room to a Dub Stage size or Theater is always tricky and it has more to do with other factors besides the X-Curve implementation.

[ggegan]

Originally Posted by minister

The Modified X-Curve is mentioned by Dolby for rooms smaller than 5300 cubic feet.

Dolby comes out here and tunes my room pretty quickly and I have watched him on several occasions. It is not all that hard. Set up mics, Pink through the system, and he adjusts the Ashley EQ's via SMAART. Would I trust myself to do it? Not until I had done it several times and tested out the translation afterward and carefully noted issues and differences. I'd rather not do it.

However, the original poster just wants to figure out how to even get the gear for 5.1 setup. He has enough to worry about with just this. And, to be honest, if he is in a room that has an 8 or 9 foot ceiling and is 12 feet by 14 feet, (or something like that) and he is 3 or 4 feet from his speakers I think it is a complete waste of time.

Furthermore, he has to have a way to easily bypass it for everything else other than "film mixes" or "film editorial" that is destined for a Dub Stage.

My experience in my rooms, and others' rooms, is that translation from a small room to a Dub Stage size or Theater is always tricky and it has more to do with other factors besides the X-Curve implementation.

I tune my own room and a few other small stages around LA. I wouldn't say it is hard, but you have to know what you are doing or else you will muck things up pretty royally. Over the years I have watched many engineers and Dolby guys tune a lot of rooms, and I paid a lot of attention, so I felt confident to start doing it myself. You are correct that tuning a small room is a whole different animal. I tune mine flat, because it is only about 1500 cubic feet, but "flat" leaves a fair amount of wiggle room for variation in terms of how you interpret bouncing pink bass frequencies on the RTA and what compromises you make.

[soundeditor76]

I use an RTA, and some EQ snapshots @ 1/6 octave of stages I mix at regularly as a baseline for my rooms overall EQ. Its a small room, but myself and a couple of my colleagues have had tremendous success with translation here in LA, applying an EQ roll-off of the highs and lows closely following the modified x-curve. I'm not here trying to argue with anyone about small rooms and the x-curve, I'm simply trying to give advice based on our success with our rooms translating quite well.

[JesseG]

Lots of great info in here guys. I still have a lot of time to find a new space to do some work and to invest in gear, so I'm sure I'll have some more questions in the near future.

Thanks!

[ggegan]

Originally Posted by soundeditor76

I use an RTA, and some EQ snapshots @ 1/6 octave of stages I mix at regularly as a baseline for my rooms overall EQ. Its a small room, but myself and a couple of my colleagues have had tremendous success with translation here in LA, applying an EQ roll-off of the highs and lows closely following the modified x-curve. I'm not here trying to argue with anyone about small rooms and the x-curve, I'm simply trying to give advice based on our success with our rooms translating quite well.

Since the stated purpose of the curve is to create the impression of a flat response by compensating for the perceived emphasis of high frequencies produced by large room acoustics, technically it should not be needed with near field monitoring where you are primarily hearing direct sound. However, IMO when it comes to small room translation, whatever works for you is kosher. In my situation, going from my very small near field room (6' from the center speaker) to large feature stages, I don't roll off any highs, and that works for me, although I do cheat down the lows a little bit.

I also ignore ITU and Dolby specs for small room speaker placement, since they don't conform to any real world situation I have ever seen and can create acoustic phasing with certain sounds like rain or traffic when panned equally to the front and rear speakers. My front speakers are in a row, not equidistant from my mix position and I put a 10msec delay in my surrounds to prevent the phasing.

[minister]

Originally Posted by ggegan

I tune my own room and a few other small stages around LA. I wouldn't say it is hard, but you have to know what you are doing or else you will muck things up pretty royally. Over the years I have watched many engineers and Dolby guys tune a lot of rooms, and I paid a lot of attention, .....

That.

Plus this:

Originally Posted by ggegan

Since the stated purpose of the curve is to create the impression of a flat response by compensating for the perceived emphasis of high frequencies produced by large room acoustics, technically it should not be needed with near field monitoring where you are primarily hearing direct sound. However, IMO when it comes to small room translation, whatever works for you is kosher. In my situation, going from my very small near field room (6' from the center speaker) to large feature stages, I don't roll off any highs, and that works for me, although I do cheat down the lows a little bit.

Gary has worked on gobs more stages than I have. From what I have gleaned, this sums it up pretty well.

[soundeditor76]

I work on the same stages Gary does in LA. He's absolutely right when it comes to perceived loudness in a larger rooms and rolling off highs, however it also applies to smaller rooms too, proportionally. All the rooms we mix in are roughly -12 to -14 db @ 16k. If you take a small room with a system that has a a center speaker that is 6' from listening position and "EQ'd flat," that would mean that you are at 0 db @ pink 85 SPL @ 16k. An RTA is going to give you the response of a room small or large at listening position, if a larger room is less bright due to the X-Curve, and a small room is flat, the SPL will not be correct because of the high gain. The same also applies to appropriate x-curve bass roll off around 40hz, which will correct low end gain. To prove my point more, I can take an RTA 1/6th octave EQ snapshot from listening position at a dub stage and come within 3-4db of my mix room's frequency response with a modified x-curve high-end roll off starting at about 3.5k and @ -12 @16k.

[ggegan]

Anyone interested in understanding the x-curve or the modified x-curve should read this paper from Dolby, which explains the theory behind it's use.

http://www.dolby.com/uploadedFiles/z...%20Journal.pdf.

The explanation of why the x-curve was adopted and the differences in the subjective linearity between near and far field monitoring is several pages into the paper.

[ggegan]

Soundeditor76, please check your PMs.

[minister]

soundeditor76, I am not questioning whether or not your work is successfully going from your room(s) to a stage where it is finalled. You are, however, under some misconceptions about room tuning, measurements, and some of the reasons the curve was developed.

Originally Posted by soundeditor76

I work on the same stages Gary does in LA. He's absolutely right when it comes to perceived loudness in a larger rooms and rolling off highs, however it also applies to smaller rooms too, proportionally.

Agreed. However, there is more to it than room EQ. Perceived loudness involves perception of short versus long sounds and how much room versus direct sound there is. In other words, ratio of transient response to room reverberation contributes largely to perceived loudness. The X-Curve is designed to address some of that, but it does not address it entirely.

Originally Posted by soundeditor76

All the rooms we mix in are roughly -12 to -14 db @ 16k.

Yikes! That is a a lot. Looking a large room X-Curve it is down around there. Looking at a Modified X-Curve it is more like -6. Is your room over 5300 cubic feet? If not, then you have a drastic curve.

Originally Posted by soundeditor76

If you take a small room with a system that has a a center speaker that is 6' from listening position and "EQ'd flat," that would mean that you are at 0 db @ pink 85 SPL @ 16k.

I can see why you might think this, but 85 SPL @ 16k? So, perforce, 85 SPL @15k, 17.5k, 14.4k, 12.5k, 10.3k, 1k, 500 Hz, et cetera respectively? If you had 85 SPL at EACH frequency, you would not be able to be in the same room!

85 dBC does not mean 85 at each frequency. You need to look at how SLM and RTA's measure SPL, what SPL actually is, and also look at the C weighting. The C Weighted network is -8.5 @16k.......

And secondly, 85 SPL in small room? That will not translate to a Large room. Your pre-dub will be far too quiet. Experienced Engineers, Mixers, Dolby, et alia recommend something like 79, 80, 82....

Originally Posted by soundeditor76

An RTA is going to give you the response of a room small or large at listening position, if a larger room is less bright due to the X-Curve, and a small room is flat, the SPL will not be correct because of the high gain.

"because of the high gain"... You mean 85 dBC @16k? You mean that if it is FLAT, 16k needs to match in both the small room and large room? You mean that if 16k is @ -12 in a large room then you need to have 16k @-12 in a small room? And therefore, if a room is "flat" then the calibration level should be 73 SPL in order to match the large room? Again, see above.

You play steady stay PINK through whatever room EQ there is -- Curved or Flat -- and set the monitor controller to the appropriate level for the room. If you set the small room to 79 (or 80, 82...) SPL with a flat EQ, it is correct. You don't match the SPL of frequency points, you read the sound pressure level of pink noise taken all together as it plays through whatever filtering you have. Let's say you have an EQ (your room EQ, I mean the device itself) set for -5dB @16k and you plot it against the ideal curve but notice that it is below it so you bring it up 1.5 dB. Your SPL reading for the room does not go from 85 dBC to 86.5 dBC!

If you read the Ioan Allen paper that Gary linked to, there is a section

Matching the Near-Field to the Far-Field

that you should read. It is largely the crux of the biscuit. The X-Curve was implemented, among other things, to make the Large far field speakers "sound" more like near fields. The near fields sounded more direct, meaning, they did not excite the room as much as the far fields.

More transient (short) sounds, like dialogue, gun shots, door slams, etc., will sound brighter in a large room because it excites the room in a way the ear perceives clearly. The room reverb adds to the perception of higher frequencies. Longer sounds are more "soupy" and our brains often cannot pick out the added RT and therefore sound more like "source" (which means flat vis á vis their EQ content).

Originally Posted by soundeditor76

To prove my point more, I can take an RTA 1/6th octave EQ snapshot from listening position at a dub stage and come within 3-4db of my mix room's frequency response with a modified x-curve high-end roll off starting at about 3.5k and @ -12 @16k.

Again, this is misguided. You don't take the room you are delivering to and match it's EQ curve. Every room is different. Every room has to have a different EQ settings to match the "ideal" X-Curve. Rooms vary in dimensions, layouts, amount of reflection and absorbtion, materials, types of speaker, etc. etc. If I were delivering sounds to a Dub Stage, I wouldn't care what it's EQ settings were. I would, if the Modified X-Curve applied to my room, work the EQ until the RTA showed a curve that matched the ideal curve plot.

There is more to it that frequency calibration in small --> large room translation. And, it is often not the high end, but the low end that is the problem in getting a mix to translate. It is very difficult to get a small room to accurately tell you what will happen to the low end of a mix when it is played back in a large room. Mix translation is trial and error and learning a room. Every room is different and it often takes a while to learn it. Even if a room is tuned "right", it takes a mixer's brain weeks to really feel comfortable in it. Heck, just changing monitors in the same room can throw off your mental calibration. Best way to attack that is to play back things with which you are intimately familiar and just work in it.

Most of the time I find that leaving a small room "flat" translates best in the testing I have done. Again, every room is different. So, for you, it may be different. But to me, there is more to the translation than the EQ curve, and most often it isn't that. I have never experienced the EXACT same perceived loudness from small-->large rooms. Close, related, in the realm of "translation", but not EXACT to my brain.

Lastly, the original poster just wants to know what gear to buy to set up his 5.1, and then how to setup his 5.1. I think him trying to implement the Modified X-Curve is not only needlessly complicated, it may not in the end be necessary. I say forget about it, set up the 5.1 and get to work.

[dr.sound]

How big is your Sound Editorial suite?
If it is the standard size that's around town I wouldn't
use a "modified X Curve" and I surely wouldn't tune it a 85
with Dolby Pink.
I mixed in a smaller room years ago and it had a modified X curve
and it didn't translate worth a damn.
To each his own. As long as the boss or client is happy so be it.
And for the record, Minister knows his stuff and signs his name
after his post.

[ggegan]

I would just like to point out that different major Hollywood dub stages that have all been EQed to the exact same curve at the exact same SPL don't even translate exactly in terms of either volume or perceived frequency response. You can't just assume that tuning the room to pink noise is going to accurately adjust things for perfect translation. There are too many acoustic issues at play that are not revealed by the process of analyzing pink noise with an RTA. I mixed several major feature films on the famous old Todd AO stage A on Seward street that never sounded the same at any other venue, and that stage received major attention from Dolby and the studio engineers because of the high visibility of the projects that were mixed there, including most of Spielberg's hit movies.

My point is that you can't just assume that adhering to a general standard is going to be the perfect solution in terms of translation. The physics involved are a lot more complicated than is convenient.

[lordshakti]

I asplso wnted to produce in 5.1 but all this discussion sounds rocket science to me..cn anyone smiplify it n tel the basics to start in 5.1?

[JesseG]

Avid's new Thunderbolt HD Native card is pretty intriguing to someone like me. I don't have a Mac Pro, and cutting the cost of that from building the setup is definitely making me consider going the Thunderbolt HD Native/HD Omni route. It's definitely pricier than other interfaces but it leaves room for expansion, eliminates third party headaches and its not THAT much more than buying third party + buying CPTK.

What are your thoughts?