Impedance Matching

[flukeyluke]

Guys,

I have a Yamaha RX-V1700 that I am using for my theatre but I also want to distribute sound from the theatre to 4 other speaker pairs around the home all at once. I plan to use just the 5.1 for the theatre and make use of the second zone for the rest of the house.

It has been suggested I need an impedance matching amp, where one audio input could be distributed to multiple locations without damaging anything. Each channel on this second amp I believe would also have indepandant volume control.

Any suggestions or recommendations?

Luke.

[xr06t]

havent heard of these boxes but i would have thought you could just run the speakers in series if you planned to have all the other speakers on at the same time..

someone will be able to confirm..

hows the t going

[flukeyluke]

havent heard of these boxes but i would have thought you could just run the speakers in series if you planned to have all the other speakers on at the same time..

someone will be able to confirm..

hows the t going

The T is going great, thanks

[Maton]

running 8 speakers all up with the main room wont happen without a speaker switching box

[c912039]

Have you bought the other speakers around the house yet?

If not, you might find it easier to go with 100V speakers in the ceiling.

The idea behind running 10V system, is that each speaker has a known load (1W,2W,5W,10W etc) which is usually selectable via a tap on the transformer which is bolted to the speaker bracket.

Then you can hook up and turn on and off as many of these speakers as you wish, as long as you do not exceed the maximum wattage rating of your 100V compatible amp.

Something like a reasonable quality 2nd hand PA amp would do nicely. (Jaycar's Redback series, when they come up 2nd hand arent too expensive).

Regards

[Hydrology]

The RXV1700 has 3 zone capability, so out of the box you can run an additional 2 pair of speakers off this amp. The other two pairs (makng up the 4) would require an impedance matching switch box, such as those form Kordz:-

www.kordz.com.au

[norpus]

The T is going great, thanks

gotta luv the T

and even more when a T-phoon

[xr06t]

so is running speakers in series a big no no?

[norpus]

so is running speakers in series a big no no?

no

[black_ops]

50-80 watts i believe or a preout to another 5.1 channel amp...

not sure on the ohm-age though..

if you plan to build a 7.1-9.1 (cinema) home theatre system be sure you got the space to house all those speakers, having them in a small compact type room will cost you speakers...

if you're looking a installing something like this system into a home be sure to seek a pro audio guy to do it these dumb sticks home installers know jack how to dial things in properly....

a 9.1 setup i would go a similar size to a standard size cinema room....

with a 7.1 setup something slightly smaller if you longevity out of your speakers that's the best policy...

i find most people on this forum seem to go through alot of amps, mainly from overtaxing the amps with the wrong watt and ohm speaker or the opposite could also be said...

most idiot salesman really know jack on that they sell as most aren't audio boffins, as long as they get the sale they don't give a shite..

as for installers i'm not knocking them either, though i would rather goto a person who installs the systems in a cinemas than a fly by nighter that only knows how to connect cable.

the ratings on a system for an amp can be a deceptive at times, what it can handle and what it can actually does handle can differ a quite alot...

[cyril]

I recommend that you distribute the line level Zone2/3 signals to the other areas of your home, and buy some cheap 2ch amps to drive those speakers.

Have you purchased speakers, purhaps you could just buy a couple of mini hifi units, most have an Auxilary line in that could be feed from you AVR Zone2/3. This setup allows those rooms to also play their own CD or FM or whatever is on the central AVR. Basic mini systems cost around $200.

If you wanted something more "integrated" then you could lookout for some audio amp kits, to fit to the rear of speakers to create a active amp setup, once again using the distributed line level feed. Jaycar do a series of modules such as thd 40W AA0227 which would be ideal to fit with a small PSU to the rear of a speaker for this application.

Jaycar do a 4way acitve line splitter AC1644 (includes composite vid) that would be suitable to distribute the line levels to various places around the home.

Cyril

[betty boop]

I recommend that you distribute the line level Zone2/3 signals to the other areas of your home, and buy some cheap 2ch amps to drive those speakers.

Have you purchased speakers, purhaps you could just buy a couple of mini hifi units, most have an Auxilary line in that could be feed from you AVR Zone2/3. This setup allows those rooms to also play their own CD or FM or whatever is on the central AVR. Basic mini systems cost around $200.

If you wanted something more "integrated" then you could lookout for some audio amp kits, to fit to the rear of speakers to create a active amp setup, once again using the distributed line level feed. Jaycar do a series of modules such as thd 40W AA0227 which would be ideal to fit with a small PSU to the rear of a speaker for this application.

Jaycar do a 4way acitve line splitter AC1644 (includes composite vid) that would be suitable to distribute the line levels to various places around the home.

Cyril

I agree. yoru average avr especially the likes of the yam are just about good enough driving a 5.1, 7.1 complement without havign to add additional load driving more additional pairs !

plenty of 2ch integrated and pwr amps always on ebay and turn up pretty inexpensive for this kind of thing, other wise if jsut ot pipe some back ground music a simple PA amp will do the same, quite inexpensive ones are aroudn and many can do a quite adequate job.

[flukeyluke]

Thanks guys for the replies, a couple of good suggestionss.

I have already cabled the speakers ( new 2 storey home ) so I have no way of running power a source if I was to chose an active system.

The KORDZ web site has some good gear that looks like it will work.

They look expensive tho

[cyril]

I hope the speaker cable have been piped individually to the HT room and you did not assume you would series them all up.

I still would attempt to take the seperate power amp route, just have a couple in the HT room with all your other gear and connected to the speaker feeds.

As others have said, your typical AVR is not really designed to do this, long speaker runs are best avoided on modern amps.

Cyril

[flukeyluke]

I hope the speaker cable have been piped individually to the HT room and you did not assume you would series them all up.

I still would attempt to take the seperate power amp route, just have a couple in the HT room with all your other gear and connected to the speaker feeds.

As others have said, your typical AVR is not really designed to do this, long speaker runs are best avoided on modern amps.

Cyril

No, every speaker has been individually cabled back to the theatre.

I think you are right on the need for a second amp too.

[c912039]

Thanks guys for the replies, a couple of good suggestionss.

I have already cabled the speakers ( new 2 storey home ) so I have no way of running power a source if I was to chose an active system.

The KORDZ web site has some good gear that looks like it will work.

They look expensive tho

The 100V speaker systems dont require any additional cabling.

With traditional 8 ohm speaker systems, you need to ensure that the total impedance of all of your speakers, does not exceed the specifications of your amp outputs.

This means that you can get into trouble, if you wish to turn off or on, individual speakers, as you will be changing the impedance load on the amp.

Turning individual speakers on and off can be quite useful - you may not want your audio sent to every speaker in the house at the same time.

Also, if you wish to add individual volume controls for each speaker in each room, these will get expensive, as they need to match the impedance expected by the amp.

You need to purchase Volume controls that match the output of your amp.

Here is an example, from Altronics, for 50w speakers (a pair).

With a 100V system, you can turn on, or off as many speakers as you like at any time, without causing problems for the 100V amp.

Each speaker has a transformer mounted on it. On one side of the tranny, you connect your speaker cables. The other side of the tranny, you connect the tap at your selected wattage to the speaker terminals. There are usually multiple wattage taps, so you can select the max wattage you want to send to each speaker.

You then add up all the wattage you have selected for each speaker (lets say you have 5 speakers, all using the 10w tap). This gives you a total of 50w load on the amp. A 60 100V PA amp would be ideal for this sort of load.

You can now switch on or off any of the 5 speakers without causing problems for the amp.

If you wish to add more speakers, you either need a larger amp, or change some of the speakers existing taps to say 5w.

You can also purchase wall mounted volume controls for 100V systems - these are much cheaper than the 8 ohm variety see here

Here is an example of Altronic's Redback range of 100V PA amps

You can purchase 100V ceiling speakers like this

or you could even take existing 8 ohm speakers like these and convert them for 100V line amps by adding one of these to each speaker.

So, in summary, the benefits of going to a 100V line system (instead of traditional 8 ohm system) are:

1. You can use your existing speaker wiring

2. You can add as many speakers as you like, by ajusting the transformer tap so not to exceed amp rating.

3. You can turn off and on any number of speakers without causing problems for the amp

4. You can add individual volume controls for each room cheaper than 8 ohm systems.

Altronics have lots of additional rack mounted 'toys' that you could add to this system, if you wanted to get fancy ( like paging, announcement chimes, matrix switchers (different sources for different speakers - exxy!), companders.

For more info on 100V systems, read here and here for a quick guide on hooking up multiple speakers (both 8 ohm and 100V type systems)

Regards

David