Setup for mixing 5.1

[Hfuy]

Hi folks.

I hope this won't be considered offtopic. I've tried asking elsewhere and got rather brief responses, so perhaps I'm asking a silly question - in which case I apologise.

I work in part as a video editor and I am occasionally being asked to create surround soundtracks. This isn't for high-end movie releases, but rather things which will go out online which we'd rather like to have 5.1 sound. Yes, there are a million technical problems with distributing more than two channel audio on the net, but that's a problem for someone else. Anyway, I'm trying to plan a system which will be accurate enough to mix 5.1 surround without it being embarrassingly wrong. Anything with more stringent requirements I wouldn't do here.

What I have now, for stereo monitoring, is a pair of JBL Control 5s and a Mass Technology 75W amplifier. Usually, I barely scratch the surface of this - the knob on the amp is only about 20% of the way up, and the mixer master gain only ever goes up to about -10dB.

Plan A was that I get some more Control 5s, although they're reasonably expensive. JBL also make the Control 1, but I'm not sure if they'll match. Then I'll need some more amplification - possibly more Mass 75s, or I have some very old Leak Delta 30s - and something sub-ish to do the LFE track. Any suggestions?

Do I need significantly more amplification for the LFE? Can I simply buy a separate subwoofer and trim it in by ear? Are the JBLs suitable as left/centre/right and surround speakers? They're intended as studio monitors really, but I'm not sure if there's any practical difference between that and "cinema" speakers. Could I reasonably buy something less expensive (and physically smaller) for the surrounds, or would that open up a can of worms regarding getting them all to match?

Best,

HF

 

[shadyJ]

The Control series is meant for places where space is at a premium. If you have the space, you might as well use larger but cheaper monitors. I would get a bunch of JBL LSR monitors and a subwoofer. You will want to keep all speakers identical for a mix. You definitely do not want to trim the subwoofer by ear if you are doing a mix. You do not need a separate amplifier for a subwoofer, since they usually come with their own amps, and you do not need amplifiers for most studio monitors, since they are mostly active speakers. You will want a way to equalize the subs to get a reasonably flat frequency response. You might think about getting a miniDSP for this. You will also want to consider getting multiple subwoofers for the flattest response. One sub usually can not produce a flat response, even with equalization, due to the way room acoustics affect bass.

On the other hand, if the material you are mixing for isn't really bass heavy, you may just want to skip the subs and get larger monitors with decent extension, like these guys. They won't do deep bass, but how much sub 50 Hz material do you want to put in web based media anyway- most playback devices of that kind of material will not be able to playback deep bass anyway.

 

[Hfuy]

Thanks for the info.

I'm not actually very flush for space - and the stuff you cited seems to be more or less similarly-priced to Control 5s, especially since I'd only need 3 more, as opposed to buying all 5 new. Anyway, the LCR/surround groups seems reasonably straightforward.

With that frame of reference as to cost, what should I pay for sub(s)? I'm in the UK, but for the sake of comparison, they seem to go from under US$100 to a couple of thousand. I'm also entirely ignorant of the calibration issue. When I've seen proper mixing stages (and cinemas) being set up, there seem to be either one or four reference microphones placed and white (pink?) noise played back. Various graphs and readouts squirm around and the room is considered accurate. Edit - the people who make that DSP offer a $75 USB reference mic which seems intended for this. Worthwhile?

Oddly enough I'm doing sci fi action movies and the rumbly LFE stuff is actually what people seem to want - and yes, I've tried to tell them that few of the audience will be equipped to enjoy it, but the thought is that we might as well be mastering it properly (or something like properly) and I guess there's some merit in that. Come to think of it, I probably know more people who have a sub connected to their gaming PC than their TV.

Thanks again,

HF

 

[shadyJ]

If you are going to be mixing some serious bass, you will really want a good response in low frequencies. If this is for serious projects, that will be vital. Sadly, in the UK, as far as I know, there isn't a whole lot of great subwoofers to choose from. I believe SVS has subs available in the UK, so I would grab a bunch of those, however many you can afford. I would go for some PB2000s or SB2000s. Stay away from Rel subs, which is a popular brand over there. You will want to dial them in for a neutral response with a procedure like this- miniDSP and umik mic.

It looks like Control 5s are the way to go for you. This should go without saying, but make sure they are all level matched when you mix. It will be a tad more involved since it looks like the amps will not be matching. Don't level match by ear.

 

[Hfuy]

I'd always assumed I'd get matching amplification for exactly that reason - I'm not sure if Mass Technology even exists any more, is the only problem!

The subs you mention mean the whole thing is now making my credit cards run and hide, but I would hope that's enough of an investment to get reasonably near what people would hear in a cinema. You'd hope?

Anyway, the setup seems fairly straightforward. The only difference is that my outputs will be coming from a probably 8-way DAC attached by ADAT to the edit workstation, as opposed to an blu-ray player or whatever.

 

[shadyJ]

The subs you mention mean the whole thing is now making my credit cards run and hide, but I would hope that's enough of an investment to get reasonably near what people would hear in a cinema. You'd hope?

Instead of buying a bunch of amplifiers for the speakers, you might just want to get an older surround sound AVR and use its amplifier in direct mode for all speakers.

The bass in many commercial cinemas have pretty powerful dynamic range. A couple mid tier SVS subs probably won't match the dynamics, but in a small room they should at least give you an idea of how your bass is turning out.

One more thing you will want to think about is filtering the bass out of your speakers to make bass management from the subs easier. You are going to want to look at getting high pass filters for your speakers. Also you will want a summed signal to get to your subwoofers, which will be an interesting challenge given your setup. I hate to say this, but it looks like if you want to do this properly, it will not be cheap. There may be inexpensive workarounds but it would be complicated. Lol, now that I think about it, for the sake of cost, convenience, and sanity, you may just want to skip the subs, use the speakers as full range, and track any deep bass in your editor window alone. You may not be able to hear the deep bass while your are making it, but as long as you take it easy on bass, it may turn out alright.

 

[Hfuy]

Theoretically, I could run a software equalizer between the edit software and the audio outputs. This might obviate external DSP. The problem would be defining the filters appropriately.

There's a piece of software called Room EQ Wizard which will create filter definitions for the APO software equalizer. I've no idea if it might be useful here.

 

[GranteedEV]

I definitely second the JBL LSR stuff.

That said, if it's part of the budget, I would be looking at Genelec 8260As

 

[Hfuy]

Genelec 8260A - er, no. Previously trembling and nervous credit cards have fled the country and are now living under an assumed identity in a remote place.

I'm going to have to investigate how the software is supposed to work, too. I have the option to pan a mono or stereo track around into a 5.1 submix, but then an entirely separate option to send that to the LFE or not. But then, again, externally we seem to be working on the idea that the main speakers will be crossed over into the LFE at some point anyway, to normalise their bass response. It's not a simple situation, is it...

Edit - by the way, I see some mention on this forum of building subwoofers. If there's significant price-performance advantage in it, I'm entirely happy with the idea of doing so. I've no idea if it's possible to get calibratable results from that sort of thing, but I have access to a shed and a table saw and I'm not afraid to use it. In the past I've built amplifiers from the transistors up, so the basic fabrication skills that are required aren't a problem.

HF