Hey guys,

So I just got my first 5.1 setup - and I'm a little overwhelmed on the setup. I read and studied a tone on the matter, and I've mixed on other 5.1 systems, but now that it's arrived and it's time to setup I'm confused on a few things :

1. Are you really supposed to roll off below 100hz and above 7k from your surround (rear) speakers? I've hear 'yes' and 'no'. If so, should it be done with a hardware graphic eq or can it be done in Pro Tools? (somehow only applying it to the surround speakers?)

2. In what order would you suggest setting up the 5.1? For example : 1. Phase alignment (using string or measuring tape) > 2. Direction (using pink noise, to approximate the mix position) > 3. SPL measurement (w spl meter) > 4. Freq Response

Is there even a recommended economic way of doing it? I read all of Dolby's documents and then some, but I didn't really seam to get this answer. Maybe I'm over thinking it?

Thanks for any and all help. I REALLY appreciate it!

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Jake @ Strawberry Sound

Quote Don Gato:

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1. Are you really supposed to roll off below 100hz and above 7k from your surround (rear) speakers?

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It depends.... That was certainly a requirement of the old analogue Dolby Stereo (Pro-Logic) system. However, the modern Dolby Digital system carried full bandwidth audio to all five main channels, so no, there's no requirement to do it. However, if your rear channel speakers are small and can't handle the bass end, then some form of bass management will be required to redistribute the LF to the subwoofer. Bass management is usually built in to such systems though.

Quote:

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2. In what order would you suggest setting up the 5.1?

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Position the front speakers where they need to be relative to the listening position, then position the centre and rear speakers, getting the angles and distances right. If you can't set them all on the circumference of a circle then get the angles right, and measure the distances. You'll have to delay the closer speakers to match the time of arrival of the later ones. Again, this facility is often included in surround system controllers.

With the speakers in the right positions you can set the SPL of each one to the desired level. With the main system sorted out you can then turn to the subwoofer. Find a position for that that works best with your room modes, giving the flattest response. Adjust the subwoofer phase alignment to provide the best match with the front speakers -- the easiest way is to use a sine wave tone at the sub's turnover frequency fed to both one front speaker and the sub, then adjust the sub phase control for maximum level. Once that's done, adjust the level of the sub for a seamless transition. This is more important if there is bass management going on, and less critical if the sub is handling LFE only.

Hugh

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Technical Editor, Sound On Sound

Hugh,

Wow thanks so much for your help. This definitely will help me get my barrings together.

1 - Makes sense because I first read that the lows and highs should be rolled in Tomlinson Holman's book, "5.1 Surround Sound : Up and Running" which is a brilliant read for 5.1 beginners but it was published in 2000.

2 - That really helps. I will be using the sub as LFE - as recommended by Alan Meyerson on episode 50 of Pensado's Place. I'm in a rectangle room (23 x 10, cushioned 'asylum' walls and a wood floor). I was thinking of setting my unity for the front 3 speakers at 85dB and my surrounds at 82dB (then the sub about 10dB louder at around 92dB)
- Is this what you recommend for getting started?

I'm also unsure of how to measure the frequencies. I happen to have an ECM8000 MEASUREMENT CONDENSER. Can I just set that up in the room and use a frequency analyzer plugin? Where do you point the mic: Straight ahead (center) or at each speaker to measure the freq response of each?

Thanks a million, I really appreciate the help.

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Jake @ Strawberry Sound