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amp (or receiver) recommendation for Polk Audio RTi A7 floorstanding speakers

I started off building a 7.1 home theater system. Based on advice received here, I changed my plans. I'm re-purposing some of my components to a dedicated music system in another room. I would like some advice on this music system. (I'm keeping the home theater system in the smaller room and using smaller speakers with it.)

I am looking for a music system that will give me smooth, sweet, soft, silky treble with instruments like the Indian sitar or sarangi. These instruments can be challenging. I hope the system also has clarity and detail and enough punch for alternative rock in a large room.

I have two possibilities for listening location. One room is 18 feet x 22 feet with a tile floor, floor to ceiling windows on back wall and 8 foot ceiling. The front wall has a book case.

The other possible room is about 25 feet x 40 feet with a vaulted ceiling (approx 16+ feet at center). Back wall is also mostly glass. Flooring will be wood soon, but for now it is carpet. Neither room has curtains (or any window treatments) over the windows.

My old room was 11.5 feet x 11.5 feet and these speakers were too much for that small space (along with a large TV).

Let's assume I can arrange either new room so that my listening position and the speaker placement closely conforms to the "golden ratio" (http://www.ecoustics.com/articles/stereo-speaker-placement-optimum-sound/).

Here are the components I already own and would like to use:

  • pair of Polk Audio RTi A7 floorstanding speakers (8 ohms) - Sensitivity (1 watt @ 1 meter): 89 dB. Recommended Amp Power Per Channel: 20 watts → 300 watts
  • pair of Polk Audio RTi A5 floorstanding speakers (8 ohms) - Sensitivity (1 watt @ 1 meter): 90 dB. Recommended Amp Power Per Channel: 20 watts → 250 watts
  • Klipsch RP-250C Center Channel Speaker (probably won't use)
  • Klipsch R-112SW Subwoofer 600 W, powered
  • LG UP875 4K BLU-RAY PLAYER (plays audio CDs) (features HDMI, USB, and optical digital audio output)
  • computer with Asus X99 Deluxe II motherboard featuring Crystal Sound 3 audio (https://www.asus.com/us/Motherboards/X99-DELUXE-II/) (features USB, HDMI or optical S/SPIF output)
  • Focusrite Scarlett 6i6 USB audio interface (if needed) (https://us.focusrite.com/usb-audio-interfaces/scarlett-6i6)

Music will be played from my computer or the LG UP875 disc player.

What I have in mind is a 2.1 system with TWO pairs of front speakers (4 speakers total). I tried a dual front speaker setup briefly and I liked it, although I understand it is unconventional. But I have the speakers and I would like to try using them all. (If that is a really bad idea, even in a larger room, I'll give up on it.)

Also, I am curious to try bi-amp'ing and the speakers support it. If I use dual front speakers and bi-amp them 8 powered channels are required.

In a smaller room, I would not need a subwoofer with these front speakers. I don't know how that will turn out in a larger room. I don't listen to bass boosted music. But I assume I'll need a subwoofer. I assume I will not use the center channel speaker at all. I can return it.

Here's what I anticipate I'll need:

  • something with an amplifier
  • something with a sub out for the subwoofer
  • something to connect everything together (and, I guess, let me choose between the disc player and computer as sources)

What I do *not* need from the new components:
  • analog input sources
  • streaming, WiFi or networking (other than what I do with the computer)
  • home theater features or video support
My budget is about $1000, although I have some flexibility. But I only have about $2300 invested in the other components (not counting the center speaker, which I won't use, or the computer which is multi-purpose). So it doesn't seem to make sense to spend a whole lot more.

I am new to audio and home theater. I'm just learning now and I want to gain some experience before I increase my budget too much. Later, if I purchase much more expensive speakers, I'll get a more expensive preamp / amp combo. In my (limited) understanding the heart of an audio system -- where the money should be spent -- is the speakers and the amp. But with my most expensive speakers (the A7's) being $600/pair, it seems unreasonable to spend more than $1000 on a preamp+amp / integrated amp / stereo receiver (whichever is recommended) for this setup. If my logic is wrong, I guess I could be talked into increasing the budget to $2000 or so.
lowoverdrive
willemj
1,036 posts
 
A 2x100 watt Yamaha AS 801 amplifier, with both optical and usb inputs, will be a more than good enough amplifier for these speakers. See here for a test of the AS 700, its predecessor without digital inputs: http://www.avhub.com.au/product-reviews/hi-fi/yamaha-a-s700-integrated-amplifier-393552 If you want to save some money, you can get an AS 701 (the same but without usb), but you will need a converter to convert one optical signal to coaxial digital. I would get the AS 801 for the extra digital input, so you can also add a Chromecast Audio streamer’s digital output if you ever decide to go that route (as I am sure you will one day do).
I am not sure I would go the two main speaker route. The resulting low joint impedance does put a bit of strain on the amplifier. Why not sell the A5’s?
A subwoofer is always a good idea, but needs some attention. At the very least I would use an Antimode 8033 room eq for much cleaner bass. I am very pleased with mine. See: http://www.theabsolutesound.com/articles/dspeaker-anti-mode-8033-dsp-subwoofer-equalizer-tas-204/
Low frequency response gets even better (smoother and cleaner) with a second sub: http://www.acousticfrontiers.com/20101029using-multiple-subwoofers-to-improve-bass-the-welti-devanti...
If you want to get an amplifier for a more ambitious system (particularly in that largest of the two rooms) and that still does not break the bank, think of a Pioneer U-05 pre-amplifier/DAC combined with a pro audio power amplifier like the recently discontinued 2x250 watt Yamaha P2500S or 2x350 watt P3500S pro audio power amplifiers. The Pioneer and the Yamaha both have professional style balanced connections for a lower noise floor. See here for a very favourable and rigorously scientific test of the latter model: http://www.homecinema-fr.com/forum/amplificateurs-de-puissance-haute-fidelite/mesures-ampli-yamaha-p...
This is what I would do, as it will have more digital inputs, and the power to drive any high quality low sensitivity speakers that you may want to buy later, i.e. you would be ready for great speakers like the Harbeth Super HL5+.
mtrot
804 posts
 
In my experience, and from my limited understanding of all things audio, the "smooth, sweet, soft, silky treble" you are looking for doesn't come cheap.  I would add shimmery, airy cymbals as another goal, at least for me. I'm not convinced that you are going to be satisfied with the quality of sound that can be obtained with ANY audio video receiver.   Quality treble is probably the weakest aspect of the sound from receivers.  Before sinking too much money into this quest, I'd recommend visiting more quality audio shops and perhaps attend some audio shows, so as to be able to find out what "good" sounds like, and the electronics that can produce it. 

Also, I fear that you may now be moving from a situation in which the room is too small for the speakers to a situation in which the speakers are too small for the room.  The rooms you're now looking at are pretty large, especially the 25X40 foot room -- that is huge.
willemj
1,036 posts
 
For a very sweet top end, Harbeth is probably the brand to go for. They are expensive, but fortunately not fussy about amplification. Their designer Alan Shaw argues that any properly designed and powerful enough mainstream amplifier will do, and for the forthcoming Bristol Audio show he intends to demonstrate their P3ESR mini monitor with a Yamaha AS 701. For his bigger speakers in a big room he recommends a lot more power (at the lowest price per watt).
willemj
1,036 posts
 
See here for their M30.1, the smallest that I think you might use comfortably in the smallest of your two potential music rooms: http://www.theabsolutesound.com/articles/harbeth-monitor-301-loudspeaker/
Or here for their M40.2, their biggest and most expensive: http://www.theabsolutesound.com/articles/harbeth-monitor-402-loudspeaker/
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