Educate me on 70.7V audio systems

Serendipity

Hi,

As Spring is around the corner (3-4 months), and given the fact that I love to spend time outdoors, I'm looking into setting up a distributed (70.7V) audio system with some TIC outdoor garden speakers, patio/rock speakers around the rear porch, and wall-mounted speakers for the entryway which has some shrubs to cover the area. For those who have seen the setup in person, you know which areas I am trying to cover with sound.

Right now I have two Polk speakers connected to an amplifier, which is being fed from the Zone 2 outputs of the Onkyo AVR. So it goes like this: Onkyo AVR --> 2ch Amplifier --> Backyard Polk speakers.

But as the need for speakers increases, it would be impractical to install an amp for every pair of speakers (front yard, back yard, side yard, patio speakers, front porch speakers, etc.) As a result a 70.7V audio system like those used at Disney World or Six Flags is what I am looking for. The amp I am considering is the following:

http://www.qscaudio.com/products/amps/isa/isa.htm

For speakers, since I already have outdoor speakers in the back, I was thinking of going with the TIC garden / underground speakers for the grass areas and some more Polks mounted to the house where there are shrubs. I would also like to have the pathway to the house lit at night. In total, there will be maybe 10 TIC "planter" speakers, 2 for the porch, maybe 6-10 around the yard and some Polks mounted to the house for the side yard. Then some additional rock speakers for the areas where they can blend easily. What is the best way to accomplish this?

txcoastal1

I have done commercial 25V and 70V setups in schools and offices using Bogen or TOA amps. The speakers are low quality with built in xfrmers and speaker taps ranging from 1/4watt to 4watts and wired daisy changed or star config. For residential cost effective whole house solutions I would look at Russound or Proficient lines of amps and multizone distribution and maybe a Sonos for braodcst of internet radio and Sonos can wireless net your PC music files....check it out.

Serendipity

Is the QSC ISA 800Ti in the link above poorly suited for this application? According to QSC's website, it says the ISA series is for Commercial Cinema and Installed Sound applications. Also as these are outdoor speakers, they will have to compete with sounds like airplanes flying overhead, cars driving by, and the occasional sound of a truck/bus diesel engine.

txcoastal1

OK looked up your TIC's....need to find out if you can run the Polk's (8ohm) off the amp at the same time you run the Tic's in 70V with outdoor transformer...there seems to be a mode selector.... which makes me question using 8ohm spkr input (polk's) and the 70v (Tic garden's at the same time). I really think this is an either (2,4,8 ohm) or (25/75/100v) not both at the same time...but you can ditch the polks and find some outdoor 25/70's

As for the size of the amp I see the Tics go upto 20watt taps...so max of 20watts x 10 spkrs =200 watts...I also doubt using more than 10watt taps...typically in an office enviroment we don't tap higher that 2watts...but a few drinks may change that...lol

I hope this makes sense.

Serendipity

I think (correct me if I am wrong), that the ISA Ti models have the ability to drive both 8/4/2 ohm loads at the same time as the 70V outputs, however power output will be reduced. I can live with that. 10 TIC speakers at 20W taps will equal 200W, plus some rock speakers (also at 20W taps) and the Polks should be within the safe limits of the amp. From the QSC website it says that "a limited number of 70V speakers" can be connected at the SAME time as the 8/4/2 ohm outputs to drive both the main sound system and additional distributed (70V) speakers. Now if this is the case, how will I match the levels of the low-impedance outputs to the 70V system?

txcoastal1

I would use independant volume controls between your amp and speakers creating zones. EX. chnl1 70v line out to a volume control input then output to your 1st leg of 70voltspkrs... same with chnl 2 line out

Then do the same with the 2chnl's you have for yor direct low impedance chnl's.

The 70v config is very forgiving since each spkr has its own transformer the 70v line can be T-tapped and junctioned off anywhere in the line or just ran in parallel...if you need to PM me your number and I can better explain

your on the right track...will be nic efor gatherings

Ron

Serendipity

Ok. So even though there are only 2 channels in this amp, you can create four zones (Ch.1 70V - TIC garden speakers, Ch. 2 70V - rock speakers, Ch. 3/4 - 8 ohm Polk outdoor speakers) and drive each zone with an outdoor volume control (obviously, 70V for the 70V speakers and a regular Niles/Russound 8-ohm volume control for the Polks).

This is good as if people are talking/eating in the Patio area the volume can be controlled separately from the garden and rock speakers to match the ambient noise level.

I may PM you later if I have additional questions, but this kind of setup seems to be exactly what I am looking for! Parts Express has the QSC ISA series on sale and the TIC outdoor speakers, along with 70V rock speakers and wall-mounted outdoor speakers. I will also keep the Polks that are currently setup in the patio area which do a great job in that location (i.e. quiet enough to not disturb the neighbors, but clear enough to be heard at low volumes - maybe Face or Polrbehr could chime in, as they have heard the setup).

Thanks!

txcoastal1

You are correct...I would use a 16awg direct buriel cable in the gardens for your 70v and gel filled wire connectors

have fun
Ron

Serendipity

Yes, and I will also use some 14awg outdoor speaker wire for the 8 ohm wall-mounted speakers. As I understand the 70V is better at transmitting power over long distances, so 16awg will work fine for that application.

I can't wait to get started on this project!

Serendipity