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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
 
Sorry for the confusion I created (it was too early in the morning and I was in haste): I meant to write amplifier but I wrote speakers. The output of the Focusrite should obviously go to the Yamaha.
I thought you were using a Windows PC.
The Yamaha is indeed a pro audio amplifier with balanced inputs (both Neutrik and TRS). That is advantageous because the connection will be less noisy if your pre amplifier/DAC has balanced outputs as well (as would seem to be the case). In the case of the subwoofer connection, trs or Neutrik to rca cables are readily available for little money and are unproblematic. The presence of gain controls on the amplifier is similarly nice, because it allows you to tame the amplifier’s pretty massive output.
As is shown in the link that I posted earlier, its smaller sister the P3500S was recently tested and measured exceptionally well. The P2500S that I gave my son for his birthday sounds perfectly fine, and I am sure measures similarly well. These Yamaha amplifiers have variable speed fans (unlike much of the pro audio competition), but they run so cool that under domestic conditions these will never come on.
willemj
1,036 posts
 
I would use the bigger of the two subs in that large room. For connections, first investigate the analogue output types of the Focusrite (I could not quickly find the information). What are yo doing with the smaller Polk sub? Will you return it?
I think you are almost there with the music system for the big room.
elizabeth
6,726 posts
 
For some different ideas..
The fact the components need time to break in is true.
I would not change anything for at least a few weeks.
The speakers will ’break in’.

As for the problem with the high frequencies..
Usually it is not a problem with the actual tweeters. it is a problem with crappy high frequency input.
A lot of digital equipment has a poor HF sounding output.
I call this stuff digital grunge.
The cheapest wat to ’control’ HF hash are ferrite clamps on the interconnects. They just dampen the higher frequencies to ’tame’ them some. AudioQuest makes some, so did Radio shack.
Amazon has PLENTY. go to electronic, type in ’ferrite choke’ You want some which will clamp over the cable exactly.. the correct inner diameter of the clamp should be the outer diameter of the cable. Several on each cable may work too.
This is a BAND AIDE fix. (So you can ’see’ if yeah this helps.. or no this does nothing for me) Cheaply.

IF they work, you might consider adding at some point a power conditioner. This kind of device also tames the ’digital grunge’ kind of the way a better power supply does in expensive components.
lowoverdrive OP
147 posts
 
kalali - "Are you sure about Yamaha P5000S? " I think willemj responded better than I could. I am not sure about anything. I'm just learning. I am, however, buying my equipment new from Amazon right now so that I can return it if I make a decision that doesn't work for me. Later, when I learn more, I'll look for bargains or used equipment, etc. Right now, I realize that I could easily buy something that seems great but just doesn't work for a variety of reasons. I did buy the Yamaha P5000S from Amazon and I can return it if it doesn't work for me.

elizabeth - RE: ferrite chokes: which cables? Should they go on speaker cables? AC power cords? HDMI calbles? Both ends? Thanks.

willemj: what other info would be helpful to know about the analog outputs of the Focusrite? It has 4 balanced analog outputs on 1/4" TRS jacks. (It also has SPDIF in and out with RCA jacks.) It also has two headphone outs using 1/4" TRS jacks. The headphone jacks carry the same signal that is routed to the main outputs.

More of the specs are available here: https://us.focusrite.com/usb-audio-interfaces/scarlett-6i6/specifications

willemj: "What are yo doing with the smaller Polk sub? Will you return it?" Yes, it is still returnable.

"I think you are almost there with the music system for the big room."

I wish to thank you and everyone on these forums. Everyone has been really helpful. This is one of the best forums I have participated in -- lots of well-thought-out and diverse opinions, lots of knowledgeable people, and a high-level of communication. Thanks so much. I look forward to learning a lot more here.
willemj
1,036 posts
 
Ok that is more info on the Focusrite. My only remaining question would be if you can play from two analogue outputs at the same time, but that is easy enough to test with your existing gear.
Continuing on the subwoofer side, I would return the Polk sub. It only creates problems in your small room, and it is not ideal as a second sub in your music system. For that music system I would strongly recommend the Antimode 8033 room eq system. It is cheap and does a great job without any fuss. For even better bass you could buy a second identical Klipsch. A second sub gives more power and a smoother response over a wider listening area.
That big room will almost certainly need some damping of high frequency reflections by curtains, rugs etc. I don’t think bass traps and the like are needed. The room is so big that room modes will be at pretty low frequencies where bass traps would need to be pretty enormous to have any effect. I would first opt for the Antimode 8033, and if you want an even smoother response over a larger area, go for a second sub. For the rationale behind mutiple subs, see here: https://www.google.nl/search?q=welti+geddes+multiple+subs&ie=utf-8&oe=utf-8&client=firef...
You have the space for what is probably the ultimate solution, the Audiokinses Swarm system: http://www.theabsolutesound.com/articles/audiokinesis-swarm-subwoofer-system/
This too can still be optimised by the Antimode.
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