Re: Video shown on PA System

E

ectobuilder

Veteran
Re: Video shown on PA System

We did a video for a mini-Gala.

The room was about 100ft x 30ft.

They had a single PA Speaker. Connected to the PA Speaker via the headphone-out was a laptop.

The video we had was playing on the laptop.

We noticed that when we cranked up the sound on the PA, the sound distorted dramatically. Therefore, what can we do in post to ensure we have the most scalable audio in our video?

PS: The laptop's volume output was also cranked to the max (could this be causing the distortion?)
 
I think you're saying that you made a video, then played it at a venue and then recorded it again on a camera - and because of the distorted sound in the room you have a rotten soundtrack?

You have the newvideo soundtrack, so add it to the old timeline, and then blend the distorted with the original clean sound and you'll get people clapping or speaking - whatever happened, but when the video starts to play with the bad sound, drop that fader and bring up the other.

That room was far too big for a single (probably) plastic box loudspeaker with built in amp. Distorted sound when cranked up is so common. It's also usual to have PA speakers in pairs to share the volume production. The trend to have these useful devices with a speaker and amp built into one box is producing useful products, but they don't do magic.

Have I understood correctly?
 
I think what he wants is to be able to master his video so that they can crank it up and not get distortion.

As Paul implied that is not really possible. You can crank most systems to the point they will distort. Since your sound was not distorted at lower levels I think it's a safe assumption that you cranked the level up on the PA past the point the speaker could handle. There isn't anything you can do in post to keep that from happening.

The PA was not big enough for the volume you wanted, the solution is to use a bigger PA. To get loud you need to move a lot of air and that takes a really big speaker or a number of smaller ones. And an amp able to push it/them.
 
Noiz2 said:
I think what he wants is to be able to master his video so that they can crank it up and not get distortion.

As Paul implied that is not really possible. You can crank most systems to the point they will distort. Since your sound was not distorted at lower levels I think it's a safe assumption that you cranked the level up on the PA past the point the speaker could handle. There isn't anything you can do in post to keep that from happening.

The PA was not big enough for the volume you wanted, the solution is to use a bigger PA. To get loud you need to move a lot of air and that takes a really big speaker or a number of smaller ones. And an amp able to push it/them.
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Yes this was the answer I was looking for. It was a non-profit on a budget, so they got the cheapest PA. From your experience which PA would be suitable for a 100 x 30ft room? Thanks!
 
ectobuilder said:
From your experience which PA would be suitable for a 100 x 30ft room? Thanks!
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IMO, without going into specific makes/models, a 'live performance' sound system.. typically, with a mixer/power amp 'head' and two stand-mounted speaker cabinets would 'cover' a room of that size.
 
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I agree with Rick a self powered mixer would be the easiest with a couple of 1x12 or 1x15 speakers plus high frequency horns on stands, 150w-300w per channel should be enough!
 
ectobuilder said:
Yes this was the answer I was looking for. It was a non-profit on a budget, so they got the cheapest PA. From your experience which PA would be suitable for a 100 x 30ft room? Thanks!
Click to expand...

I don't really speck systems and the last one I worked on probably cost five digits so not in your price range. But as Rick mentioned a "PA" system is probably never going to be great for video. It's tailored to human voice and talking, so it's either going to filter out or not handle well big low end or high treble. You probably want something aimed more at live music reinforcement because it will better handle the wide dynamics and range of videos.
 
A "live music reinforcement system" is normally refereed to as a "PA"... at least here. Not a totally correct terminology, but we're all idiots here in Manhattan and don't know any better. Sorry.
 
hmmmm

A lot of "systems" sold as PA systems are basically for lectures and such. Technically PA = Public Address. But your right that PA is a generic term also.

To elaborate what I was talking about, those all in one packages that small outfits by for a "PA" are not designed to do wide range material. They are basically gussied up bullhorns. I've dealt with tons of them over the years and never found any that sounded decent.

You can call a large concert set up a "PA" but it's a totally different beast.

http://en.wikipedia.org/wiki/Public_address_system

These PA systems are really not suitable http://www.amazon.com/b?ie=UTF8&node=11975001

Where these mostly are http://www.guitarcenter.com/Live-Sound-Packages-Live-Sound.gc

Rick you said basically the same thing, though you used the term "Live performance system" as opposed to "Live Music Reinforcement system".

What we both meant was a "PA" system that is designed for live music/ performance as opposed to something designed to help someone making a speech heard in a crowd.
 
It's not been 'public address' for about 30 years. The term has morphed into meaning sound system. For a while in the 80s, a few books changed 'public address' in performer assistance', but it didn't catch on - so any system is now just a 'PA', with no real meaning.

For what it's worth, the cheapest active types which are wiping out powered mixers are rated at around 300W RMS - ones with 15" drivers often go a little higher. So much depends on the level you want to achieve but 100 x 30 ft is pretty large, if the 100ft is the depth. For music, I'd be looking quite a bit higher in amplifier wattage - 600W-1Kw a side at least, to give you enough dynamics. The active types are popular because you can forget hefty speaker cables, and just send audio to them at different levels - most have balanced and unbalanced inputs, and will accept mic or line level signals. In a big room, even with heavier speaker cables, you need to keep the cable lengths down.
 
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