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Yamaha RX-A800 and Polk RTI A7's. What to do?


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#1 of 12 OFFLINE   Porcupinepuffer

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Posted January 28 2013 - 12:51 AM

I recently aquired A7's as my front mains. Center A6, surround A3's, and rear surround polk R15's. Everything is great, except I noticed these A7's are very thirsty for juice. I purposely went down from A9's for this reason. However, I do believe (and according to everything I've read on many forums) that more amplification is required for these bad boys. Currently we're looking at possibly 95w a channel on a really good day, and less when the whole 7.1 system is running. My situation is this, I would like to keep my existing receiver, and disconnect the bi amp posts on the a7's and use only the midrange/tweeter out of my receiver while powering the two woofers with an additional amplifier. I'm curious what amplifier would be good for this job? I'm not looking to blow the roof off my house here. I'm looking to take some of the strain off my existing receiver and give these speakers what they deserve. I'm thinking a 2 channel amplifier with a gain control knob to control how sensitive the volume will be as I turn it up on the receiver to try and match with the midrange/tweeter. I don't want to get really complicated and expensive with having 2 amplifiers that power each speaker in a full fledged bi/amp setup. I have a lot of knowledge with car audio, but this is a bit over my head as there's so many amplifiers and most are all designed for pro audio setups/cabinets. I don't want some ugly contraption that looks out of place in front of my tv either. Input would be greatly appreciated.

#2 of 12 ONLINE   schan1269

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Posted January 28 2013 - 02:26 AM

Have you thought about using the AVR in "bi-amp"? The lower crossover on the RTi A7 is 125. Remove the jumpers, set-up bi-amp...set your crossover at 125-ish(whatever choice you have close) and connect. Then you can see if you really need more power.

#3 of 12 OFFLINE   Porcupinepuffer

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Posted January 28 2013 - 02:31 AM

So upon some further investigating, it seems the simplest way to do this is to completely cancel out my fronts altogether from my receiver and use the front main RCA outputs to power a 2 channel amplifier for the polks without any of the bi/wiring/amping I was originally looking it. Since it seems almost every brand of amplifier, (be it NAD, Rotel, Emotiva, etc) rely on the volume control by the RCA's only. I'm currently looking at a Rotel 2 channel amp that delivers 130wpc. Now I'm assuming this 130wpc is a true, and very strong wpc that should blow the doors off the "95 wpc" I get on my Yamaha? Does it sound like a decent upgrade for powering the rti a7's? I know they can go right up to 300w per speaker. But I really don't need some 600watt amplifier, nor can I afford a very large one.

#4 of 12 OFFLINE   Porcupinepuffer

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Posted January 28 2013 - 02:37 AM

Have you thought about using the AVR in "bi-amp"? The lower crossover on the RTi A7 is 125. Remove the jumpers, set-up bi-amp...set your crossover at 125-ish(whatever choice you have close) and connect. Then you can see if you really need more power.

The problem with that is that I really enjoy, and collect 7.1 blu-rays and this receiver requires the sacrifice of the rear surrounds for bi amping... I know the newer models of the Yamaha receiver, (starting at the 1020 model) actually allow you to keep your rear surrounds while giving an extra set of connections for bi amping, which is awesome, but I don't want to upgrade the receiver. I also heard that the bi/amp receivers don't really give you any extra bang by connecting to more channels, (even tho they claim so many watts per channel). I'm to the understanding you're still at the mercy of the same built in amplifier's overall power handling. Keep in mind that my receiver is the lowest wattage of the RX-A series receivers... I have loud and fantastic sound from all the others. Just the A7's are underpowered. I also don't want to be heating/running this receiver close to it's max output.

#5 of 12 ONLINE   schan1269

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Posted January 28 2013 - 02:47 AM

What you "heard" depends on a bunch of things... 1. Confusion between bi-amp and bi-wire 2. People having no clue because of the confusion 3. The actual capabilities of your AVR Your Yamaha actually does use its crossover when bi-amped. Which means you get "pre-crossover bi-amp". Which is the proper way for it to be done. And yes, I missed your "use of 7" before. My only other question.... Are you including the A7 in the bass management or not? If you are using them as "large" change them to small and that might mitigate some of the problem. Cause I'm not exactly sure how a 89db speaker can be considered power hungry.

#6 of 12 ONLINE   schan1269

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Posted January 28 2013 - 02:52 AM

So upon some further investigating, it seems the simplest way to do this is to completely cancel out my fronts altogether from my receiver and use the front main RCA outputs to power a 2 channel amplifier for the polks without any of the bi/wiring/amping I was originally looking it. Since it seems almost every brand of amplifier, (be it NAD, Rotel, Emotiva, etc) rely on the volume control by the RCA's only. I'm currently looking at a Rotel 2 channel amp that delivers 130wpc. Now I'm assuming this 130wpc is a true, and very strong wpc that should blow the doors off the "95 wpc" I get on my Yamaha? Does it sound like a decent upgrade for powering the rti a7's? I know they can go right up to 300w per speaker. But I really don't need some 600watt amplifier, nor can I afford a very large one.

Your Yamaha(and everybody else does this as well) does not produce 95x7. Not even close. The AVR is measured on two channels running and whatever that is...they quote as x5 or x7. That is why, on here, you see ALL THE TIME that "AVR wattage ratings are meaningless". You are probably only getting 45-60 x 7. Yamaha doesn't list an "amp draw" on the rear of the AVR(it is in the manual...which you have). To come up with "closer to reality" you find the amp draw(might be written in watts already), remove roughly 70 for video processing...divide the rest by 7. That is how you can come up with a "closer to reality" wattage of your AVR...and every AVR for that matter.

#7 of 12 OFFLINE   Porcupinepuffer

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Posted January 28 2013 - 10:50 AM

Cause I'm not exactly sure how a 89db speaker can be considered power hungry.

Maybe the efficiency is somehow divided by how many speakers there is? Look at the RTI A9's. They have 3 woofers, 2 mids, 1 tweeter and an efficiency of 90db and still demand a big pile of power. Whereas mine is 2 woofers, 1 midrange, and a tweeter with an efficiency of 89db. I know for sure the A9's aren't going to play louder on my receiver then then A7's. My main's before this were Energy C-6's. They're known as a more power hungry speaker and required a higher volume setting just to hear them then what my cheapy $100 technics 3 ways required. If I leave one C-6 hooked up one side while I have one of the A7's on the other, the volume I get out of the A7 is a good deal lower, and flatter sounding.

#8 of 12 ONLINE   schan1269

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Posted January 28 2013 - 11:26 AM

How do you "get" they "require" a big pile of power? They are 89db efficient. 1 watt is 89db 2 is 92db 4 is 95db 8 is 98db 16 is 101db 32 is 104db. By here, your ears should start to hurt. 64 is 107db. By here, your neighbors want to call the cops (the 800 "should" have this much power) 128 is 110. 256 is 113. I don't want to be in the house. 512 is 116. I don't want to be in your yard.

#9 of 12 OFFLINE   Porcupinepuffer

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Posted January 29 2013 - 04:31 AM

I see what you're saying and how the paperwork says they're decently efficient compared to 87db or less speakers. But it still makes no sense to me. My RTI A3's have a sensitivity of 89db, which is the same as my A7's... The A7's are essentially the same thing as the A3's but with 2 woofers and a bigger crossover. They're obviously more speakers to power, so the same efficiency factor isn't going to sound exactly the same at the same volume level if I have an A3 on the left side and the A7 on the right... The A3 is going to be louder. I also found a nice set of Pro audio Peavy SP4's that weigh 133 lbs with dual 15 inch woofers and a horn tweeter that's 52" high by roughly 2 feet by 2 feet that takes 2000watts of power. The efficiency of that speaker is 100db? So according to the efficiency DB rating, those massive, enormous peavey speakers are going to blast like crazy from my home theater amp? I somehow doubt that.

#10 of 12 ONLINE   schan1269

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Posted January 29 2013 - 07:09 AM

No, actually...the A7 is "louder" and more full than the A3. Speaker efficiency is inverse to size. The more speaker there is...the louder it is. Your thought process(and you aren't the only to think it) is completely backwards. Bigger speakers need less power... Point being...play The Wall from CD(not "streamed/downloaded") and tell me that the A7 won't trounce all over the A3. Short story... My 3 main theatres all have tower speakers in all positions. Why? They are easier on the amp than bookshelves, period.

#11 of 12 OFFLINE   Porcupinepuffer

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Posted January 30 2013 - 02:03 AM

Holy cow my head is going to explode. Yeah I can't play the wall because I hate Pink floyd with a passion. I know their sound is supposed to be fantastic through a good stereo, but they just don't tickle my fancy. I'll play around with the speakers some more when I get some banana plugs. I just don't want to swap them around and continue breaking the wire strands. I was looking more at amplifiers, and they don't really give them away for free. Considering the receivers do all the switching/decoding/ frequency control, I'm almost shocked at something only responsible for amplifying costs the same or more then the receiver. I'm really finding these A7's have such a flat sound to them. There's not much coming from the tweeters. I keep hearing people say these are "bright" until broken in. But my Center channel delivers louder, crisper high range then these. I have yanked out the tweeters and did test them to make sure they worked. I do have 3.3 ohms or so across their prongs. I can hear them working when I put my ear to them. But they're not even half as loud as my C-6's titanium tweeters. Thanks for the input.

#12 of 12 OFFLINE   Porcupinepuffer

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Posted February 02 2013 - 01:52 AM

Just found out my Energy C-6's are 92db room efficient. Most "copied" for sale listings show them as being 89db, which is wrong. Upon further searching, I found the proper specifications for the whole line, which explains why they are easier/louder then my A7's at the same power level. I've done some more fine tuning with my 7.1 speaker levels. I have everything setup in a comfortable place. When watching back my favorite blu-rays, I'm noticing "extra sounds" that my C-6's never picked up on before. The sound is loud, crisp, clear, and phenominal considering I have the smallest of the RX-A series of Yamaha receivers. I'm not going to bother with any amplifiers or bi/amping. Seems like it will be too much hassle and money for what I'll gain.




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