Your Universal Remote Control Center
RemoteCentral.com
Custom Installers' Lounge Forum - View Post
Previous section Next section Up level
Up level
The following page was printed from RemoteCentral.com:

Login:
Pass:
 
 

Topic:
70 Volt Audio article
This thread has 9 replies. Displaying all posts.
Post 1 made on Sunday November 25, 2018 at 09:52
Ernie Gilman
Yes, That Ernie!
Joined:
Posts:
December 2001
29,821
Fred Harding has written a good introductory article on 70 volt speakers for CEPro. At this moment there’s a link to it above the thread list here in the Custom Installers Forum. Someone please provide the link here: I’m writing on an iPad mini and don’t know how to get it.

Most of us, at some point, consider using or have to use a 70 volt setup to make things work. Even if you only do two channel high end audio, it’s worth your while to understand the totally different approach to multiple speakers and large rooms that is 70 volt. It ALWAYS pays to know more about your general subject than just what is required for your day to day work!

Fred’s article is brief but good and accurate. I’d like to add an answer to the first question that people ask when talking about 70 volt systems: why are they usually mono?

70 volt systems are excellent for evenly filling large or oddly shaped spaces. Restaurants come to mind, but some stadiums use it, too! Stereo’s goal is to provide one “sweet spot” in a space with a three dimensional sound image. (Successful surround does that, too.)

You can use the different 70 volt power taps to put a little more sound, or a little less, here or there. Unlike in a stereo space, there are no seats where you can’t hear the other channel. Stereo amps are based on 8 ohm or 4 ohm loads, so the number of speakers you can have is limited and must be deployed in matched numbers. With 70 volt, if you have 12 speakers and must add a 13th, it’s no big deal, especially if your initial design was properly conservative!

Look up how to connect balanced and unbalanced sources to balanced inputs. Learn the correct way to mix the two channels of a stereo source into one. You have a powerful tool at your disposal when you understand 70 volt systems.
A good answer is easier with a clear question giving the make and model of everything.
"The biggest problem in communication is the illusion that it has taken place." -- G. “Bernie” Shaw
Post 2 made on Sunday November 25, 2018 at 11:23
buzz
Super Member
Joined:
Posts:
May 2003
3,719
Post 3 made on Sunday November 25, 2018 at 11:31
highfigh
Loyal Member
Joined:
Posts:
September 2004
7,869
Stereo is for smaller spaces unless the event needs stereo for effect, but only briefly. Large venues have areas where the 'other speaker' isn't audible at all, so achieving stereo in a way that doesn't screw it up for others is difficult.

There's also the perception that 70V sounds bad- it's can, but doesn't have to. I did an audio upgrade for a school gym system and used JBL Control 26D in-ceiling speakers, a Control SS2210 sub, Soundcraft EPM-8 mixer, Shure wireless mic and a Crown CDi1000 amp- if I could have replaced the back boxes, I would, because they weren't made for these speakers, or even the old Atlas speakers that I replaced. They were too shallow and the baffle had a gap at each end, but they were installed with conduit and the cables passed through most of them, so I put some strips of thin plywood over the gaps and used the original grills to cover them. Since the low end was cut off and they're about 24' from the floor, it wasn't as much of a problem as it would be if they were lower and used for full-range.

Everyone who I spoke with after it was done was happy with the sound, some were impressed- probably because the old system sounded like a pocket radio.

And I did speak with Fred when I was choosing the mixer- he was OK with the rest of the equipment choices.

Last edited by highfigh on November 25, 2018 11:40.
My mechanic told me, "I couldn't repair your brakes, so I made your horn louder."
Post 4 made on Sunday November 25, 2018 at 12:42
roddymcg
Loyal Member
Joined:
Posts:
September 2003
6,767
On November 25, 2018 at 11:31, highfigh said...
Stereo is for smaller spaces unless the event needs stereo for effect, but only briefly. Large venues have areas where the 'other speaker' isn't audible at all, so achieving stereo in a way that doesn't screw it up for others is difficult.

There's also the perception that 70V sounds bad- it's can, but doesn't have to. I did an audio upgrade for a school gym system and used JBL Control 26D in-ceiling speakers, a Control SS2210 sub, Soundcraft EPM-8 mixer, Shure wireless mic and a Crown CDi1000 amp- if I could have replaced the back boxes, I would, because they weren't made for these speakers, or even the old Atlas speakers that I replaced. They were too shallow and the baffle had a gap at each end, but they were installed with conduit and the cables passed through most of them, so I put some strips of thin plywood over the gaps and used the original grills to cover them. Since the low end was cut off and they're about 24' from the floor, it wasn't as much of a problem as it would be if they were lower and used for full-range.

Everyone who I spoke with after it was done was happy with the sound, some were impressed- probably because the old system sounded like a pocket radio.

And I did speak with Fred when I was choosing the mixer- he was OK with the rest of the equipment choices.

My team did the Vail golf course a couple years back with JBL Pentdant speakers and Crown amps. We can get this room pretty rocking, especially when it is empty and we are the only ones there. :)

[Link: vailclubhouse.com]
When good enough is not good enough.
Post 5 made on Sunday November 25, 2018 at 18:37
davidcasemore
Super Member
Joined:
Posts:
January 2003
3,237
Always check your local codes before bidding on one of these systems. Some jurisdictions require the speaker wire to be run in conduit which changes everything.
Fins: Still Slamming' His Trunk on pilgrim's Small Weenie - One Trunk at a Time!
Post 6 made on Monday November 26, 2018 at 10:12
highfigh
Loyal Member
Joined:
Posts:
September 2004
7,869
On November 25, 2018 at 18:37, davidcasemore said...
Always check your local codes before bidding on one of these systems. Some jurisdictions require the speaker wire to be run in conduit which changes everything.

The one I updated had been installed in the '50s and it was up to code. That's the reason I couldn't easily change the boxes (I thought I mentioned that). The cable was actually shielded.
My mechanic told me, "I couldn't repair your brakes, so I made your horn louder."
Post 7 made on Monday November 26, 2018 at 10:15
highfigh
Loyal Member
Joined:
Posts:
September 2004
7,869
On November 25, 2018 at 12:42, roddymcg said...
My team did the Vail golf course a couple years back with JBL Pentdant speakers and Crown amps. We can get this room pretty rocking, especially when it is empty and we are the only ones there. :)

[Link: vailclubhouse.com]

The guy who was there for my walk through said he wanted four big box speakers in the corners and I said that would be the last choice. He was a bit surprised, but I had been told about his idea before I even became involved and when I explained why, he understood. When he heard it for the first time, he raised his eyebrows and said "Wow!". I left some headroom, but limited the maximum output.
My mechanic told me, "I couldn't repair your brakes, so I made your horn louder."
Post 8 made on Monday November 26, 2018 at 14:23
Fred Harding
Super Member
Joined:
Posts:
October 2001
3,334
Thanks for the kind words. There will be a follow up with an examination of audio matrixes later this week.
On the West Coast of Wisconsin
Post 9 made on Monday November 26, 2018 at 17:02
Fred Harding
Super Member
Joined:
Posts:
October 2001
3,334
Follow up article just landed.

[Link: cepro.com]
On the West Coast of Wisconsin
Post 10 made on Tuesday November 27, 2018 at 07:49
jrainey
Active Member
Joined:
Posts:
September 2010
596
I have done a fair bit of 70V in commercial and landscape systems but Fred taught me the basics. I am going to be the a huge number of people got their first 70V education from Fred.
Jack Rainey - Full disclosure...reformed integrator, now mid-Atlantic manufacturers rep for: Integra, Paradigm, Anthem, Parasound, Atlona, LG TV's and Metra Home Theater...among others


Jump to


Protected Feature Before you can reply to a message...
You must first register for a Remote Central user account - it's fast and free! Or, if you already have an account, please login now.

Please read the following: Unsolicited commercial advertisements are absolutely not permitted on this forum. Other private buy & sell messages should be posted to our Marketplace. For information on how to advertise your service or product click here. Remote Central reserves the right to remove or modify any post that is deemed inappropriate.

Hosting Services by ipHouse