RTI A9, Amp Wiring, etc.

klennop

Hello Everyone,

First post here and also building my first real system used for a little bit of everything.

I am debating between between the Onkyo 1007 and the 3007, right now I have a Denon 3310 but I am returning it because bang for buck the new Onkyos seem like winners. I have a Denon that is over 15yrs old and I never really warmed up to Onkyo but apples to apples I have to try a Onkyo out.

So far I bought:

CSiA6 for Center
OM3 Rears
DSW Pro 600 Sub
Fronts I have A7s at home but I am going to switch to A9's because I can get them for about $150 more than what I paid for A7's.

Now my questions are: I have read the A9's are power hungry or at least need a lot of power to warm up or reach their potential. I don't know if Bi-Amping the Onkyo will give them enough power? In theory the other idea I thought of seems like it would work but I am not sure, so here goes. Could I run just the normal front channel from the Onkyo to the top of the A9's and then get another 2 channel amp like a Adcom 555 and run it to the bottoms? I just am not sure if things will hit at different times and not sync up. In a perfect world it should work but???

So if the biAmping the Onkyo isn't enough power for the A9's. Would the Adcom 555 have enough power or any other reasonable priced suggestions?

Thanks for any comments or suggestions!

Keith

klennop

Or would I be better off just keeping the A7s and bi amping those or using a Adcom 200X2 amp on them?

John K.

Keith, welcome to Club Polk. You ask what you'd be better off doing. The answer is that you'd be better off not taking seriously claims that the RTiA9s are "power hungry" when the Polk specs show that they're in fact slightly more sensitive than average. Unless Polk has falsified the numbers, which certainly isn't the case, the RTiA9s require slightly less power than many other Polk speakers(including one dB, or about 26%, less than the RTiA7s, incidentally). Both of the excellent Onkyo receivers that you're considering have more than enough maximum power capacity to drive the RTiA9s to levels beyond what's safe if you care to avoid permanent hearing damage.

Get the speakers and receiver that you really want and enjoy the great sound. Don't hesitate because of stories that lack a factual basis.

klennop

Thanks for the welcome and sharing some info John.

I figured I would get the A9's and see for myself. I also hear people saying how "bright" the Polks sound, and I take that with a grain of salt. You can make any speaker sound "bright" or "warm". The phrase "bright" seems to be very catchy with the Polks on other forums. The power hungry is also something mentioned a lot about the A9's, which I take with a grain of salt also. But I do know there are a lot of speakers in the A9's so it will take more power than say the A7's to make them sound good, that is common sense. I did notice that the 1 db difference on the spec sheet also vs the A7's. I guess I just want to be prepared for it and also if I have a good lead on an amp, I would like to snap it up.

I just am unsure about the whole BiAmping theory. I understand bridging, ohms, etc. However I haven't seen any info on the amount of watts the speakers get by BiAmping out of say one of the Onkyos I am interested in.

Say if the receiver is rated at 130 watts per channel. When you biamp, does it send the 130 to the top and 130 to the bottom of the A9's? Or does it only bump the power from 130 to 180 out of the receiver? Can I am use the receiver for the tops and an amp for the bottoms, is that legit or possible? Or should I just run the Adcom 555 to the A9's alone or ditch the Adcom and just power them off the receiver.

Thanks for any comments or suggestions.

By the way I did take back the Denon and the A7's and am going for the A9's. Also if anyone runs across a good deal on the Onkyo 1007 or 3007 please pass it on to me.

albino_puddle

Hi. I'm also new to Polk. I've recently purchased the A7's and am wondering about biamping them to my Denon 989 (sorry I'm Canadian, don't have the American model number). I understand how it works and how to wire it, I'm just a little bit nervous about over powering the speakers. Will biamping them run too much power into them? thanks for the help

tonyb

albino_puddle wrote: »

Hi. I'm also new to Polk. I've recently purchased the A7's and am wondering about biamping them to my Denon 989 (sorry I'm Canadian, don't have the American model number). I understand how it works and how to wire it, I'm just a little bit nervous about over powering the speakers. Will biamping them run too much power into them? thanks for the help

No, using a receiver to bi-amp, your still using the same amp inside the receiver. Not worth it in my opinion. True bi-amping is useing 2 seperate amps.

klennop

tonyb wrote: »

No, using a receiver to bi-amp, your still using the same amp inside the receiver. Not worth it in my opinion. True bi-amping is useing 2 seperate amps.

So can you use the amp in the receiver to power the top of the speakers and a dedicate amp to power the bottom speakers? That would be using 2 amps.

klennop

Why do all the newer receivers give you the option to biamp out of them if there is no benefit to doing it?

albino_puddle

klennop wrote: »

Why do all the newer receivers give you the option to biamp out of them if there is no benefit to doing it?

this is where I'm getting confused. So there is no benefit at all to wire this way?

Rocco1

albino_puddle wrote: »

this is where I'm getting confused. So there is no benefit at all to wire this way?

Yes there is a benefit to powering the speakers this way. You will want to check the power specs on the AVR to verify how much power is fed when wired like that.

Your best bet is going to be going with a external amp. You may want to consider, if its in the budget, getting a pre/pro and start looking at amps. it will cost more but this is the way to really get your system sounding good.

klennop

Thanks for replying Rocco.

Now what I have noticed is a lot of the AVR manuals tell you how to biwire or biamp but they don't seem to tell you the power they put out then? I find that odd.

What are your thoughts on using the receiver amp and also an external amp for the same speaker. Hence actually biamping because you are using 2 amps. Like I said earlier in a perfect world it should work but I have never heard of anyone doing it.

tonyb

klennop wrote: »

Thanks for replying Rocco.

Now what I have noticed is a lot of the AVR manuals tell you how to biwire or biamp but they don't seem to tell you the power they put out then? I find that odd.

What are your thoughts on using the receiver amp and also an external amp for the same speaker. Hence actually biamping because you are using 2 amps. Like I said earlier in a perfect world it should work but I have never heard of anyone doing it.

Because in the real world, most don't use a receiver to bi-amp. If you use the receiver's amp section and a seperate amp, which one will be more powerfull ? Will they have the same speed, the same power reserve ?

In alot of low and mid level receivers, you may read 100 watts per channel, but in reality, in may be 80 watts for the front 2 channels and 40 watts to all the other ones, indicating the amp in the receiver doesn't have the reserve to power all channels at peak. In my opinion, your wasting the wire, but do as you wish, somethings you just have to try for yourself. Lots of threads here to learn from grasshopper, use the search button and all shall be revealed.

John K.

Keith, no, there's no actual benefit from the so-called "bi-amping" feature that some of the HT receivers advertise. The reason that the manuals don't describe a difference in power is that there isn't any. All the power comes from the one power supply section in a receiver and simply funneling it to a speaker through two sets of output transistors(one previously unused for back surround speakers)rather than one can't double the power(as some imagine)or increase it by any amount.

Also, note that principles of audio technology often have to be applied, not just "common sense". Very often(including several examples in the Polk lineup)the biggest speakers with the most drivers in a given line have a higher sensitivity than the smaller ones with fewer drivers and use less power at a given sound level. Again, you should do well with either of those Onkyo receivers and your RTiA9s. You might take a look at the Audioholics store for good prices on those receivers.

klennop

Thanks for the help everyone. It gives me some insight on what route I want to take.

gp4jesus

Great comments John K & tonyB about the pitfalls of mix/matching amps of different brands etc. Additionally, the wealth of info available else where in this forum; couldn't have said it better myself.

tonyb wrote: »

No, using a receiver to bi-amp, your still using the same amp inside the receiver. Not worth it in my opinion. True bi-amping is using 2 seperate amps.

My long winded $.02 worth:
IMHO to bi-amp correctly requires an electronic XO (EXO) & , as tonyb mentioned, 2 seperate amps delivering 2 separate bandwidths to the different parts of your speaker system. Polk's literature tell you to remove the jumpers then connect them to different amps-essentially bi-amping however the speaker's internal filtering in the speaker is still in the signal path. Consider that many HT fans use a powered Sub is, in so many words, the first step towards bi-amping their systems. Going to the nth degree, for say your left & right fronts, is the next step effectively tri-amping that part of your system.

Some advantages to the EXO are the amps are connected directly to the drivers resulting 0 power loss netting increased output* for the same input & in most cases improved damping* particularly in the LF portion. The drawbacks are cost, greatly increased complexity, and a tremendous amount of effort to make it work right.
* I can tell you from years of experience, done correctly, will net you mind blowing "effortless sounding" dynamics!

That same internal filitering compromised by $. Another thread in this forum authored by Zingo has recommended XO parts upgrades to improve sound quality for very little $.

If you have enough amps* of the same make/model NOW, then buy an EXO and let the tweeking begin! If not, I'd persue their (John & TonyB) suggestions as they're simple and proven to get the results you seek quickly, simply, and @ lower $ & complexity.

*I have (had for years!) 3 Hafler XL 280s along w/a 4 channel EXO I use for my LCR. Also a 4th*** for Surrounds driven full range
*** 5th purchase pending for Center rears


I've read some threads about systems on this & another HT forum that have the fronts (LCR) each w/ high-end ($$!!) mono blocks. The other channels driven w/same brand lower powered stereo amps. These guys had been down the bi-amp road. Didn't mention about EXOs in their experiences.

I'm crazy and have 20+ years experience* messing with b/tri/quad amped systems. Cheers, have fun tweeking, & movie viewing!!
* having some test gear like RTAs helps

garypen

John K. wrote: »

Keith, no, there's no actual benefit from the so-called "bi-amping" feature that some of the HT receivers advertise. The reason that the manuals don't describe a difference in power is that there isn't any. All the power comes from the one power supply section in a receiver and simply funneling it to a speaker through two sets of output transistors(one previously unused for back surround speakers)rather than one can't double the power(as some imagine)or increase it by any amount.

So, are you saying that in a 7.1 AVR rated at 100wpc, the 7 output stages all share a common "pool" of 700w? And, that if only using 5 channels, it would raise the output to 140wpc (assuming equal input signal and load)? And, in stereo mode would be able to put out a whopping 350wpc? Because that is certainly what you and folks like tonyb are implicitly implying.

And, as such, I would have to disagree with your assesment.

While there can be no argument that using separate power amps will provide better bi-amping results than an AVR (and that actively crossing over the signal before amplication is even better), the original poster should definitely see some benefit when using the AVR's internal bi-amp configuration, especially when using a higher-end AVR, such as the better Denon, Onkyo, etc models with their discrete high current outputs.

Klennop - If the option is there in your AVR, I'd say go for it. Of course, you will lose the surround back speaker and zone 2 amp options. But, if they are not important to you, go for bi-amping your L/R.

And, while I prefer the "Denon sound" to that of Onkyo, that 3007 looks hard to beat at the $1499 street price I'm seeing everywhere. (Even Crutchfield has it at discount, and they NEVER discount current models.) I'm almost thinking of giving it a trial myself! (The comparable Denon 4810 has an msrp of $1000 more.) I just don't know if I can get over that butt-ugly Onkyo front panel styling they've been using for a few years now.

superjunior

garypen wrote: »

So, are you saying that in a 7.1 AVR rated at 100wpc, the 7 output stages all share a common "pool" of 700w? And, that if only using 5 channels, it would raise the output to 140wpc (assuming equal input signal and load)? And, in stereo mode would be able to put out a whopping 350wpc? Because that is certainly what you and folks like tonyb are implicitly implying.

And, as such, I would have to disagree with your assesment

nope, thats not that they're saying...:rolleyes:

concealer404

garypen wrote: »

So, are you saying that in a 7.1 AVR rated at 100wpc, the 7 output stages all share a common "pool" of 700w? And, that if only using 5 channels, it would raise the output to 140wpc (assuming equal input signal and load)? And, in stereo mode would be able to put out a whopping 350wpc? Because that is certainly what you and folks like tonyb are implicitly implying.

And, as such, I would have to disagree with your assesment.

No, what they're saying is that it may be rated at 100wpc with 2-channels driven. That number may change with all 7 channels driven.

Now, if the receiver says 100wpc with all 7 channels driven, then that's a different beast. I still wouldn't biamp. But that's me personally.

garypen

superjunior wrote: »

nope, thats not that they're saying...:rolleyes:

Perhaps you can enlighten me as to what they were saying. (And, as long as you're at it, why they were correct that bi-amping would result in no additional power output, if you agree with that assessment.)

concealer404 wrote: »

No, what they're saying is that it may be rated at 100wpc with 2-channels driven. That number may change with all 7 channels driven.

I don't recall anybody using the word "may". They seemed quite definite that no power gain would result from bi-amping. And, it also sounds like you are still implying that there is a total pool of power, and adding outputs reduces the per channel power in a direct relation to the number of channels used.

superjunior

garypen wrote: »

Perhaps you can enlighten me as to what they were saying. (And, as long as you're at it, why they were correct that bi-amping would result in no additional power output, if you agree with that assesment

I beleive what they are saying (and ops correct me if I'm wrong) is a receiver - say 100 wpc for example, is not going to magically give you 200w with bi-amping. your still getting the same amount of power from the receivers internal amp. Also most receivers over rate their power specs. my pio for example is rated at 130wpc x 7. In reality its probably 90 to 100 wpc and less with all channals driven. so yes I do agree with their assesment.

garypen

superjunior wrote: »

I beleive what they are saying (and ops correct me if I'm wrong) is a receiver - say 100 wpc for example, is not going to magically give you 200w with bi-amping. your still getting the same amount of power from the receivers internal amp. Also most receivers over rate their power specs. my pio for example is rated at 130wpc x 7. In reality its probably 90 to 100 wpc and less with all channals driven. so yes I do agree with their assesment.

If what was meant was that the OP won't get double the power output, then anyone would probably agree with that, including me. But, that is not what was being said.

They were saying that there would be no improvement in power output at all from bi-amping using the internal amp of an AVR.

That is just wrong.

klennop

Sorry for lighting a fire here guys but at least people are talking and stating opinions etc. instead of just keeping info to theirselves.

nguyendot

How often are you going to reach the max output of any of these amps anyways? 1 watt on my theater speakers is like 99db... 1w/1m

klennop

OK so in the $300-$500 used amp pricing what would be a good match for the A9's and why would one of them be better than the other.

nguyendot

Adcom 555mk2
Emotiva XPA-2 or XPA-3

Adcom is known for being well rounded. People here like Emotiva...and it'll probably be newer.

klennop

garypen wrote: »

And, while I prefer the "Denon sound" to that of Onkyo, that 3007 looks hard to beat at the $1499 street price I'm seeing everywhere. (Even Crutchfield has it at discount, and they NEVER discount current models.) I'm almost thinking of giving it a trial myself! (The comparable Denon 4810 has an msrp of $1000 more.) I just don't know if I can get over that butt-ugly Onkyo front panel styling they've been using for a few years now.

I had a new Denon at home but I am going for the Onkyo because of bang for buck. I really like the sound from my old Denon and I have always heard they had a warmer sound than the Onkyo. I just really never liked the older Onkyos so that is why I went with Denon in the past. The Onkyo 1007, right now is only $1000, I was lucky to get the Denon 3310 for around $900 but the Onkyo is just so much better on paper! I do agree with you also about the Denons looking nicer. So either I will be really disappointed in the Onkyo or I will be happy about the switch. I did notice something that was odd about the Onkyo, it doesn't have any outlets on the back like the Denons.

garypen

If you are going with external amps for your mains, as it looks like you might, the Onkyo/Denon "sound" debate may be moot, depending on whether it's their amps or preamps that give each one its perceived unique sound.

gp4jesus

Klenop: an Adcom 555* in any variation will lift a pair of A5/7/9s off the ground! If you did that* your LR amp would loaf which is certainly not a bad thing! You'd then need to follow that with a compatable mono amp for your center chnl. Adcom makes/made a three channel that would solve that problem.
* or another of similar capabilities in the watt/current department!

On these "bi-amp" replies, I agree w/much of what everyone said. The discussion that caught my attention was the 7 X 100 watt channel receiver. Used as a 5 channel receiver it MAY be capable of "more power per channel" in the form of peak current. Hence the "140/ch interpretation." As one reply alluded to:
1. the power supply can deliver only so much before it "runs out"
2. the output devices can handle just so much (V X I) before they run into "problems."
3. This amp section COULD ouput 200+/ch... ... if the user would sacrifice some channels, bridging them, leaving 3 or 5 channels. Stability would be a problem, if unbridged, these can't handle 4 ohm loads. I wouldn't do it unless they could handle 2 ohms.

On the topic of 200 watts/ch using bi-amping: Lets say I wanted to tri-amp a pair of A7s, electonically XO'd at the Polk frequencies, 4th order. Everything else being equal, I'd drive the tweeters & mid-woofers (6.5") w/mono blocks*, 15-20W & 100+ W respectively. The woofer/subs: I wouldn't settle for less than 400 watts/ch**; a PS that can deliver 50-100 ampers/ch**. These are not hard-fast rules, just what I'd do.
* MB for better channel separation. Class A; Single ended triode for tweeters
** note: stereo works-bass is mono

I hope this illustration gets across that having 100 watts for each the woofers AND tweeters doesn't net 200 watt/ch. In summery I find as you move DOWN the frequency spectrum you need move UP power/current output. Tweeters need quality power, not quanity (super clean, but not alot to get the job done.) Woofers/subs on the other hand(below 200 hz) need quantity, not quality. Power, really, current is king; lots of current in reserve, doesn't have to be real clean, big PS with lots of straight forward filitering. In fact, bass "uses" most of power in a full range system. Chief reason I like powered subs w/big amps-I'm quick to recommend a twin if space & $ allows. Mid woofers fall in between-a blend or compromise these.

I'd love to conference call all the people on this thread to get their take on some bi/tri amp stuff. As I said earlier in this thread I've experience. I don't have all the answers!

garypen

gp4jesus wrote: »

In summery I find as you move DOWN the frequency spectrum you need move UP power/current output. Tweeters need quality power, not quanity (super clean, but not alot to get the job done.) Woofers/subs on the other hand(below 200 hz) need quantity, not quality.

Absolutely 100% correct. That is what you will see in any professional concert sound reinforcement system, all of which are actively crossed-over before amplification. By far, the majority of the power amps are dedicated to the bass drivers.

quadzilla

To throw in my .02, I run Rti12s, basically the previous model of the A9, and they do like power. Going from a 130 wpc receiver to a single amp doing 300 wpc, then to bi-amping with a pair of amps at 850 wpc, I noticed definite improvements at each step. While it is true that, as stated above, the speakers don't require a huge amout of power to make sound, they do seem to require a lot of power to bring out the detail and imaging they're capable of. At least that's been my experience. I also noticed that, after running with big power for a few weeks, the speakers warmed up considerably. They're now quite revealing for mid-fi level gear. This opinion seems to be shared by all who have heard this set up. As always, YMMV.

Also, it's not necessary to run two amps on each channel. I bi-amp by running each amp in mono for each channel, so I run one channel in and get two outputs from the amp that I run to the high and low input. It works amazingly well.

Take care, and welcome to the forum.

klennop

Thoughts on a Carver TFM-45? The THD looks to be high on it so???

I know people like the TFM-35X but I can't seem to find any of those used.

I found a used Adcom 555 original model for $300 also. How much better are the newer ones besides a fan and external fuses.