expert recommendations..

[mgraham112]

Here is my situation that I would greatly appreciate some expert advice..

I am setting up my whole house audio system(not surround sound). I have an adcom gfa 555 amp and I am using various klipsch ceiling speakers. I need some help deciding on a good preamp to go with the adcom. And also here's the other situation. Of course the adcom is a 2 channel amp and it is going to push a 6 zone system with stereo speakers in 4 and summing speakers in 2 zones. My question is, would it be better to use imp matching volume controls with a distribution hub before i get to my amp. Or would it be better to use non imp matching volume controls and use a imp matching speaker selector or a imp matching hub. From what i have heard, I should stay away from the speaker selector cause they suck too much power from my system. Please give me some thoughts..

thanks

[mgraham112]

Also, i was curious about volume controls. I mean i can pay $50 for an imp matching niles volume control or i can get a cheaper one for $30. Do you think the difference is noticable if any at all?

[Tarheel]

Mgraham112.....Welcome to the forum...I see from your profile that you joined today. Sorry I can't help you with your questions but someone is sure to respond with some good information. Good luck with your project.

Chuck

[DrWho]

What kind of functionality are you hoping to achieve with this setup? Do you only want one room playing at a time, or a combination of all the rooms? Ideally you would be running a 70V system for this application so that you didn't have to worry about maintaining a proper impedance for the amp to drive.

I think your best option would be to purhase a 70V amplifier dedicated to the task. If that's not an option, then I think you can convert the output of your adcom to a 70V system. And then you can just use the typical 70V volume knobs on the walls in your rooms.

The only other option I can think of would be to build a custom speaker selector box that ensures a series-parallel wiring scheme that keeps the impedance between 4 and 16ohms to the amplifier. The system would get overly complex though if you wanted to have full control from every room (essentially you'll need to run a few more wires everywhere). Yes, it's something that can be done, but I wouldn't recommend going this route simply because you wanted to use your amplifier.

Welcome to the forum.

[mgraham112]

I never even considered using a 70v system. I thought those were just for PA, churches, etc. I am looking to play my system through out my house with CD's, radio, ipod... If I used an impedence matching unit like the niles sms-10c(http://www.nilesaudio.com/product.php?prodID=SMS-10C&recordID=High%20Power%20Impedance%20Matching%20System&categoryID=Speaker%20Selectors&catcdID=7&prdcdID=FG00260) wouldnt this do the same as a 70 volt system. Also i could use impedance matching volume controls set at 8x with 12 speakers and get an impedance of 5.3. I really dont care for a speaker selector unless i had to. So now I am completely lost.. I could always sell the adcom if it was necessary. They are going on ebay for about $400.

[DrWho]

70V systems were designed exclusively for distributed sound - which is what you're trying to do in your home. Honestly it's the best sounding approach you can take. Don't all the klipsch in-walls and in-ceiling speakers already come with a 70V switch on them?

The problem with autoformers is they change the frequency response of the system - moreso when you have dissimilar speakers on the same line (like you plan to do in two of the rooms).

You might find this PDF a bit overkill, but I think it touches all the bases:
http://www.bogen.com/support/productcatalog/pdfs/SysDsgn.pdf

I'm pretty sure there's a way to convert a normal amplifier to a 70V output, but I don't know how it's done. Maybe someone will chime in.

[mgraham112]

Thanks for the article. That was very informative. I just want the best sound from my system and the ability to really rock it out if the time calls for it. So if the 70 volt system is the way to go and I am going to sell my adcom, where is the best place to buy a 70 volt amp and accessories that I will need. And also what brands do you recommend. Thanks for all your input. It is very helpful. Thanks

[Guest BobG]

I do not agree about 70v systems being appropriate for most multi-zone home applications. Typical 70v amplifiers and the transformers built into the associated speakers have very poor bass extension and overall sound quality. This does not have to be the case as high grade transformers offer good bandwidth and freedom from saturation, but because most 70v gear is built for low-fidelity background sound, it's tough to get high fidelity from most of the readily available product.

Someone else will have to answer your question about imp matching VCs vs, impedance strip. Not my area of expertise.

[DrWho]

I originally thought Bob's comments were only true for the cheaper equipment...I just did a bit of homework and can't believe how expensive the "acceptable" implementations are. [] It would be cheaper to use your existing amp and purchase a dedicated transformer - but even then you're looking at around $500 and still needing volume controls after that.... To think that I've worked with these systems for years and never bothered to check the prices []