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

Login:
Pass:
 
 

Page 1 of 2
Topic:
NewB here, whole-house audio Q's
This thread has 26 replies. Displaying posts 1 through 15.
Post 1 made on Tuesday September 25, 2007 at 12:30
Neurorad
Super Member
Joined:
Posts:
September 2007
3,011
Hello everyone! Been lurking a couple months, since I bought a house that came with whole-house audio already installed.

To the point, MUST I bought an amplifier to run the whole-house audio?

2nd zone powered AVR (not yet purchased), Niles SPS-6 speaker selector, impedance-matched VC's, 7 speaker pairs.

I understand I'll be getting low wattage. I want to save money. I don't want to spend the money on keypads (and rewiring), and more than 2 zones (#1 for media room). I will eventually buy an amp, but moving is expensive, and want to wait, if I can.

Local store wants to sell me the amp. I will use the store's CI for installation, as the speaker (and IR extender) wires are a mess. I'll save my RC Q's for another thread.

Thanks a bunch!

Edit - thanks in advance, RemoteCentral.com has been a great resource.
TB A+ Partner
Believe nothing, no matter where you read it, or who said it, no matter if I have said it, unless it agrees with your own reason and your own common sense. -Buddha
Post 2 made on Tuesday September 25, 2007 at 12:38
Tom Ciaramitaro
Loyal Member
Joined:
Posts:
May 2002
7,958
If your AVR has seven channels and your main room is only 5.1, then the two spare channels can run the rest of the house.

However, the second amp idea is preferable, since you are doing 7 speaker pairs. Let the outboard amp share some of the work or make sure that AVR has something to keep it cool.
There is no truth anymore. Only assertions. The internet world has no interest in truth, only vindication for preconceived assumptions.
Post 3 made on Tuesday September 25, 2007 at 14:53
SOUND.SD
Loyal Member
Joined:
Posts:
April 2006
5,523
On September 25, 2007 at 12:30, Neurorad said...

Local store wants to sell me the amp. I will use the
store's CI for installation, as the speaker (and IR extender)
wires are a mess.

Best of luck! This should prove to be a good decision.

Its still a good idea to ask some questions here. Knowledge is power and can help you decide if your CI is knowledgeable and suits your needs.
Bulldog AV - San Diego, CA
www.bulldog-av.com
[Link: facebook.com]
Post 4 made on Wednesday September 26, 2007 at 01:54
Ernie Bornn-Gilman
Yes, That Ernie!
Joined:
Posts:
December 2001
30,104
On September 25, 2007 at 12:30, Neurorad said...
To the point, MUST I bought an amplifier to run the whole-house
audio?

no, as others said, but there have been some threads here recently where the consensus seems to be that you're pushing your luck if you use the second zone amp in an A/V receiver for more than two, maybe three rooms. If you didn't have the switcher, you could use the internal amp for two rooms (three if you play quietly!) and an outboard amp for the other four rooms. Buy a fifty or so watt receiver off of ebay and use it as the outboard amp. Get a brand different from your main amp so remote controls don't affect two units at the same time.

2nd zone powered AVR (not yet purchased), Niles SPS-6
speaker selector, impedance-matched VC's, 7 speaker pairs.

The SPS-6 is an impedance matching device, so if you already have impedance matched VCs, set them to X1 (time one). The SPS-6 splits up the output, meaning that speakers in room A will be louder when playing alone than if you also play speakers in rooms b,c,d,e,f,g. If you need to play some room louder at the expense of the others, that's the ONE case where I prefer an SPS-6.

My preference is to just use impedance matching VCs set to X8, or 8X, or whatever has an eight in it, and not use the SPS-6. Why? When you leave the room, you turn down the volume. If you have the switcher, you'll run into cases where you thought you turned the volume down, you'll go to the room and turn up the volume, then realize that you have to go back to the switcher and turn it on.

Either that or six months after you wire this up, you'll realize that you NEVER go to the SPS-6 and turn any room off. So it was a waste to put it in.

I understand I'll be getting low wattage.

Yeah, but it's AMAZING how effective, say, five watts is for background music.
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 5 made on Wednesday September 26, 2007 at 08:52
Fred Harding
Super Member
Joined:
Posts:
October 2001
3,456
Ernie, I'm going to respectfully disagree re impedance matching vc's vs. a selector box.

I'll try and be brief. The objective is to protect the amplifier.

With impedance matching vc's, you set those to the appropriate setting. It increases the amount of impedance per vc, whether the speakers are on or off.

With the selector box, you set it to increase impedance, yes, but when a room is turned off at the volume control, no additional impedance is on the bus.

Essentially, if a person uses impedance matching vc's, they are loading the amplifier more with speakers off then the same situation using a selector box. To my mind, that means that I'll get better sound quality with a selector box. The great Eric Johnson, now with Universal, explained this to me years ago. If it makes sense, credit to him; if it does not, it is my interpretation.....
On the West Coast of Wisconsin
Post 6 made on Wednesday September 26, 2007 at 09:44
Mr. Stanley
Elite Member
Joined:
Posts:
January 2006
16,954
Fred, Interesting. I've never been fully comfortable with impedance matching v.c.'s, and am sure that there are a lot of guys that are using impedance matching v.c.'s along with impedance matching switchers which would seem to be choking the heck out of the signal, not to mention eating up a lot of amplifier power?

To address the origional question, the second zone COULD be run into a switcher, and there would be "background" level music, be it a temporary measure, until a secondary amp could be added on to beef things up a bit.
"If it keeps up, man will atrophy all his limbs but the push-button finger."
Frank Lloyd Wright
Post 7 made on Wednesday September 26, 2007 at 13:12
Eastside A/V
Select Member
Joined:
Posts:
September 2006
1,782
I only sell Impedance matching VC's, and also use sps or hps 6's in this type of set up. The VC's are under used as I leave them at the standard settings, and let the speaker selector do the work. In my mind its worth the extra 10/VC for the flexibility, and protection if complications arise.

I have hooked up may 'zone 2's' this way, but always recommend a dedicated amp for this purpose, and tell customers that want to pass on the dedicated amp for the time being that even though it works now, we may need to add the amp down the road. Adding the amp has happend about 50% of the time within a 2yr window. I would also recommend using a custom amplifer like niles or russound that can handle more challenging loads just to be safe, rather then the $50 Ebay special.
Bryan Levy
www.eastsideav.com
Gallery: [Link: eastsideav.com]
Post 8 made on Thursday September 27, 2007 at 23:02
tca
Advanced Member
Joined:
Posts:
December 2005
845
Bryan,

When you do add an amp to a situation as you described above in your post, do you add a single channel amp and still use the speaker selector to distribute to the 6 rooms, or a 6 or so channel amp and skip the speaker selector? Also, when you use a 6 channel speaker selector with impedance protection, about how many watts are being distributed to all six rooms when all rooms are on?
Post 9 made on Friday September 28, 2007 at 03:02
Ernie Bornn-Gilman
Yes, That Ernie!
Joined:
Posts:
December 2001
30,104
Newbie note: In all of the following, in case you're not really conversant with the concepts, know that a higher impedance load on a power amp means the amp puts out less current and less power. Higher impedance intuitively sounds like it means more of a load, but it means less of a load because less power can come out of it (sort of -- and close enough for this discussion).
On September 26, 2007 at 08:52, Fred Harding said...
Ernie, I'm going to respectfully disagree re impedance
matching vc's vs. a selector box.
I'll try and be brief. The objective is to protect the
amplifier.

Exactly.
With impedance matching vc's, you set those to the appropriate
setting. It increases the amount of impedance per vc,
whether the speakers are on or off.

With the goal being that the overall impedance of all speakers together is not less than 8 ohms. That is, the amp is never overloaded when ALL volume controls are turned up all the way. This matching also ensures that each speaker gets its proportional share of the power.
With the selector box, you set it to increase impedance,
yes, but when a room is turned off at the volume control,
no additional impedance is on the bus.

Are you saying that when one of the selector box switches is turned off, that the impedance seen by the amp increases? That could be, but if it's one of the boxes where speaker volume goes up when fewer speakers are used, then the box is changing the loading such that the amp always sees approximately the same impedance. If all speakers stay at the same volume whether one or six switches are on, THEN the impedance seen by the amp is higher with fewer switches on.

Now about volume controls: if the volume control does not go open when all the way down, then, yes, "no additional impedance" is seen by the amp when the volume control is all the way down.

But what is the effect of this? When eight VCs feeding 8 ohm speakers are set to the X8 position, then the impedance when all are on is 8 ohms, the normal impedance you'd want the amp to see. It's not likely that raising this impedance, say to 16 ohms(as for instance if there were an 8-position switch box and half were off), would improve the sound of the amp -- first, it would simply be delivering less power, and second, if this were the case, people would be designing 16 ohm speakers to get better sound out of amplifiers! Or would be selling impedance matching devices to make 8 ohm speakers appear to be 16 ohm speakers for better sound. Nobody's doing that.
Essentially, if a person uses impedance matching vc's,
they are loading the amplifier more with speakers off
then the same situation using a selector box.

That's totally true. But they are never overloading it under any circumstance, and overloads are where performance suffers. With all the VCs presenting their load, the amp is seeing the load it was designed for, so that shouldn't give "worse" performance. The other side of this is that loading an amp with 12 ohms or 16 ohms won't give better performance than loading it with 8 ohms.
To my mind,
that means that I'll get better sound quality with a selector
box. The great Eric Johnson, now with Universal, explained
this to me years ago. If it makes sense, credit to him;
if it does not, it is my interpretation.....

This whole line of thought relies on the assumption that an amp will sound better with a load higher in impedance than 8 ohms. I think that's a false assumption. All of the things stated about how the impedances will vary are true. I just don't think they matter to the performance of the amp.
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 10 made on Friday September 28, 2007 at 08:11
Eric Johnson
Universal Remote Control Inc.
Joined:
Posts:
May 2001
705
Ok, I admit I'm a little rusty at explaining this, but I want to give it a shot. You essentially get two different kinds of system behavior when you use IM volume controls vs Resistive Protection Speaker Selectors (like those made by Niles).

Let's look at resistive Speaker Selectors first. Here's how they work:

The speakers are wired to switches that alllow all speakers to be connected in parallel to the amplifier. So, if 4 pairs of 8 ohm speakers are connected in parallel, the load the amplifier sees is 2 ohms, unacceptably low (generally, so low that the amplifier will fail quickly). To protect against this, the installer engages a resistor using a switch the client never sees on the rear of the selector. The resistor has a value of about 2.5 ohms (4 room selector) or 3 ohms (6 room selector). It is inserted in SERIES with the speakers. Thus the amplifier sees a much more comfortable and safe load of at least 4 ohms.

Here's a speaker selector in use. When all the rooms are playing, approximately half the amplifiers power is completely wasted as heat, so you see a reduction in the loudest level the speakers can play. However, the magic of sound reproduction is that the loss is only 3 decibels. That's not a very large difference in volume! The human ear perceives that the volume is reduced by half when you lower the level by 10 decibels.

The magic of the speaker selector is that when only one room is playing, although the resistor is still in series, the loss of power is almost undetectable since 80% of the power is distributed to the 8 ohm speaker, only 20% of the power is wasted as heat. A 20% reduction in wattage reduces the actual volume of the speaker by less than one decibel, typically undetectable to the human ear.

Now, what happens with IM volume controls. As Ernie and Fred have said, the IM volume control is set to the 8x setting. Now, each speaker has a 64 ohm impedance. Even if eight pairs of speakers are connected in parallel, the amplifier is completely happy, it sees an 8 ohm load. If the amplifier is 100 watts at 8 ohms each speaker gets an eighth of that, so about a 10 decibel loss in volume. The system appears to play half as loud as the speaker selector system.

Mixing the two systems is actually fairly common. It kind of covers all the bases.

The biggest disadvantage of the speaker selector alone is that you cannot add any more rooms later. If you purchase a 6 pair selector and later decide you want a pair of speakers in the new gazebo area in a side yard, you can't add the speakers without replacing the speaker selector. With IM volume controls you can add speakers and rooms almost ad infinitum...

Another disadvantage of the speaker selector system is that it optimizes the load to 4 ohms. That's fine for a good outboard amplifier, but many of the 2nd Zone amplifiers built in to AVRs won't be happy with 4 ohms and might shut down or even prematurely fail (taking the home theater out with the multi room system). IM volume controls make a cheap amplifier (like those built in to a $1000 AVR for the 2nd zone) quite happy when playing 15 pairs of speakers at background levels.

The third disadvantage of the speaker selector is touted as their advantage. If as Ernie says, you turn off a speaker pair at the switcher, you have to walk all the way back to the switcher to turn it back on. For this reason, many installers hide the switcher from their clients and instruct them to always turn off a room using the volume controls.

The biggest disadvantage of the IM volume controls alone is their effect on loud listening. When a really good song comes on, you just can't crank it as loud as you might like. However, you can certainly play any indoor speakers louder than a vacuum cleaner, which is pretty loud for most people.

The other, less predictable disadvantage of any kind of in wall autoformer volume controls, is their effect on the sonic quality of a pair of expensive (over $1000) speakers. Although a speaker selector uses resistors to achieve impedance protection (which really cannot affect the sound quality of an expensive set of speakers), autoformer volume controls literally put a reactive coil in parallel with the speaker to achieve volume reduction. Even though these coils are designed for reasonably flat frequency response, they can have strange effects on some high end speakers, blurring detail, adding harmonics to the bass notes etc. Now, you can get rid of almost all those effects if you simply turn the volume control all they way up and it is set to 1X Impedance Magnification. However, if the control is set to 8x, you are stuck with the sound quality. Not an issue if you have a pair of $500 ceiling speakers, but something to be concerned about if your den has a pair of high end speakers for critical listening...

Hope this helps, and I hope Ernie or the great, famous and incredibly dedicated Fred Harding (he really is!) will comment on anything I misremembered from my days teaching impedance matching....
Best Regards,
Eric
Post 11 made on Friday September 28, 2007 at 08:25
oex
Super Member
Joined:
Posts:
April 2004
4,177
ive said it before and ill say it again.

ZONE 2 OFF OF AND AVR IS NOT DESIGNED FOR THIS PURPOSE. Zone 2 is designed to drive a single pair of speakers. If you set it up for fixed volume out, then into a switch box, the VCs, it will shorted its life allot.

Lynch me for saying it, but if money is an issue buy a used sonance sonamp 260 to drive the 6 pairs of speakers. You'll still need a swtich box or IM volume controls. You may even be able to score a sonance 1230 amp or 1250 amp. For cheapest route IMHO is a 260. Used they can be had for 100-150 with freight.

good luck. I Would allow your dealaer to supply, maybe ask for a discount on that 1 item, one BUT if not check out:

[Link: cgi.ebay.com]

[Link: cgi.ebay.com]
Diplomacy is the art of saying hire a pro without actually saying hire a pro
Post 12 made on Friday September 28, 2007 at 08:48
stereoguy823
Advanced Member
Joined:
Posts:
February 2005
885
I just wanted to thank Eric Johnson for a very informative piece about impedance matching. Remote Central is very lucky to have contributors like you.
Sticking to what I'm good at.
Post 13 made on Friday September 28, 2007 at 09:08
tca
Advanced Member
Joined:
Posts:
December 2005
845
this is all excellent info. Is there a formula for figuring out how many watts are actually getting to a pair of speakers? For example, you have an amp which then connects to a 6 way speaker selector, which then connects to 6 pairs of speakers. Let's say you have all 6 on, what would the wattage be? Then let's say you have on 2 on, and so on.. I know you need about 5 watts at least for background music, but I'm not sure how many watts I can get to each set of 6 speakers when using an amp and a speaker selector. I would like to get enough wattage to each of the 6 sets of speakers to really pump, but I don't know if this is possible when using a speaker selector.
Post 14 made on Friday September 28, 2007 at 10:31
Fred Harding
Super Member
Joined:
Posts:
October 2001
3,456
It's important to remember that it's more then just wattage that makes this thing work. You also need current.

Crudely put, current allows the amplifier to better control the motion of the loudspeaker. The higher the current, the more likely the speaker is going to do exactly what the amplifier asks it to do. With multiple speakers, you need a higher current amplifier.

And no, not every manufacturer provides accurate current specifications, if they provide them at all.
On the West Coast of Wisconsin
Post 15 made on Friday September 28, 2007 at 10:47
tca
Advanced Member
Joined:
Posts:
December 2005
845
Thanks fred. I'm just looking for a ballpark formula to figure out the wattage when using an amp with a speaker selector so I can have an idea what each room will sound like, ie background music, loud, rock out, etc. I know about 5 watts is background, 20 watts maybe loud, 60 watts rock out, etc.

Last edited by tca on September 28, 2007 12:51.
Page 1 of 2


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