Best amp for Polk Rti series and Yam 2500

[AVRat]

Also, on the Yam 2500 you can set the bass out to sub, both or front. Would it help the rti 12's if I set the bass out to "both", instead of "sub"?

That's really a judgement call specific to your environment. Try both and see which sounds better. Sounds like you're on the right track.

 

[MacManNM]

That's really a judgement call specific to your environment. Try both and see which sounds better. Sounds like you're on the right track.

Just to let you know, running both the mains and the sub in the same frequency domain makes it VERY difficult to adjust and setup. Doing this introduces room modes that are almost impossible to compensate for. This is why most people recommend against it, unless you have a very good parametric EQ and can flatten the room out.

 

[mtrycrafts]

Mtrycrafts,
Either I didn't phrase my thoughts well, or you misunderstood my point about the Rti 12's. If I remove the metal jumpers from the binding posts then the speaker is essentially a 8ohm speaker. Add the jumpers and you have a 4 ohm speaker. Therefore, if I biamp, each channel of the amplifier only has to power a 8ohm load, not a 4 ohm load, right? Also, the Rti 12's have a 90dB efficiency, which seems to be middle of the road fo sensitivity.

Is that what the maker is stating? Can you double check them on this by measuring?
90 dB sensitivity is pretty good, really. Youy can get to 107 db spl pretty quickly

 

[mtrycrafts]

Not true, when bi amping the polks the, Z actually goes up, not down. It will be easier on the amps and it will sound much better.

Is this unique to the Polks?

As to being an easy load, sensitivity is a factor as well. Being 90 dB sensitive, he shoul dnot have much of a problem. He will go deaf before running out of power?

 

[mtrycrafts]

I currently have the Rti 12's set to small and x-over at 60hz. The Yam. 2500 only has universal x-over setting, so I'm stuck with tweaking, trying to find the right x-over for all my speakers. The YPAO sets the x-over high IMO, like 160 or 200hz. I get different results with YPAO's x-over, so I manually set it. Also, on the Yam 2500 you can set the bass out to sub, both or front. Would it help the rti 12's if I set the bass out to "both", instead of "sub"?

Try an 80 Hz crossover, THX spec, if you can.

McmanNM,
I've read that 130w from an AVR is not the same as say 200w form a seperate amplifier. The seperate amp will produce a better sound b/c of the current along with the added watts. I'm not able to test or demo different amplifiers (2 channel v/s 5 channel), so I'm trying to make my best judgement on what I read and learn here and other places before I decide to buy.

200 watts is more than 130 watts, if you need the extra 70 watts of power, for some reason. 130 is a lot of power with a 90 dB sensitive speaker.

But, if you drive that 200 watts to 130 and compare, you will be surprised of the results if you remove bias from the perception equasion
Also, don't forget, there are a lot of mythology on the net about audio, perception, etc.

 

[MacManNM]

Is this unique to the Polks?

No, this is true on all speakers that strap high freq drivers and low freq drivers in parallel.

As to being an easy load, sensitivity is a factor as well. Being 90 dB sensitive, he shoul dnot have much of a problem.

They are not 90 db, that is an 8 ohm rating, the speakers are 4 ohms. It is a very misleading spec.

He will go deaf before running out of power?

If he sits 1 m away maybe

 

[Buckeyefan 1]

But, if you drive that 200 watts to 130 and compare, you will be surprised of the results if you remove bias from the perception equasion
Also, don't forget, there are a lot of mythology on the net about audio, perception, etc.

Please explain all the bias you would remove when comparing the "perception equation."

I still stand by my claim that even you could hear a difference between this Insignia unit at 30 watts and a McIntosh 1201 power amp running through a Yamaha RXV2500 at 30 watts (in stereo and through some Paradigm 8 ohm towers. http://www.bestbuy.com/site/olspage.jsp?skuId=7016481&type=product&productCategoryId=cat03031&id=1099394773324

 

[Stepheng]

They are not 90 db, that is an 8 ohm rating, the speakers are 4 ohms. It is a very misleading spec

Does this mean that if I biamp (unstrapped @ 8ohms) as opposed to one single channel (strapped @ 4ohms) the sensitivity would be 90dB for the high and low freq. drivers. If true, then biampping seems to be better than going with one channel strapped @ 4ohms.

 

[Stepheng]

I've learned that certain amplifiers match up better with certain AVR's. What I'm trying to determine is which amplifiers work best with a yamaha 2500?

Then I can determine if I need to biamp the Rti 12's with a seven channel amp, or go with a 5 channel amp since I have a 5.1 system, or do just a 2 channel amp for the mains and let the 2500 power the center and surrounds.

 

[Buckeyefan 1]

I've learned that certain amplifiers match up better with certain AVR's. What I'm trying to determine is which amplifiers work best with a yamaha 2500?

Then I can determine if I need to biamp the Rti 12's with a seven channel amp, or go with a 5 channel amp since I have a 5.1 system, or do just a 2 channel amp for the mains and let the 2500 power the center and surrounds.

I've got to side with Mac and say to get a good two channel amp to biamp your mains. Your 2500 has plenty of power to drive the rest of your system, especially if you alleviate trying to drive those 6 - 7" woofers on your towers. A solid 2 channel power amp is going to deliver more power than a 5 or 7 channel amp into each channel with less strain (unless that amp weighs 100+lbs). If these 5/7 channel amps put out the type of current they claim, you would need massive heat sinks. Heat sinks these amps don't have. IMHO, these 5/7 channel power amps are really no better than a flagship receiver's power section. Check out the guts of this two channel amp, then take a look inside one of the 5/7 channel amps.

 

[Stepheng]

I've got to side with Mac and say to get a good two channel amp to biamp your mains.

What you're saying is I need 2 two channel amps if I plan to biamp both mains (4 channels needed for biampping).

 

[mtrycrafts]

Please explain all the bias you would remove when comparing the "perception equation."

I still stand by my claim that even you could hear a difference between this Insignia unit at 30 watts and a McIntosh 1201 power amp running through a Yamaha RXV2500 at 30 watts (in stereo and through some Paradigm 8 ohm towers. http://www.bestbuy.com/site/olspage.jsp?skuId=7016481&type=product&productCategoryId=cat03031&id=1099394773324

Oh, you know, doing a double blind listeing to solidify the perception to real sound not ones that are imagined much of the time.

Well, that would depend on the Macs output impedance and frequency response. Otherwise, when you level match them, remove the bias, good luck.

Others have tried with competent amps, none have succeeded. Perhaps one is not a competent amp?

 

[mtrycrafts]

They are not 90 db, that is an 8 ohm rating, the speakers are 4 ohms. It is a very misleading spec.

That would depend on the voltage used, right? So if it is at 2 watts input, 2.83V, you will still have lots of power.

I am looking into the impedance question.

 

[Buckeyefan 1]

Others have tried with competent amps, none have succeeded. Perhaps one is not a competent amp?

I've read those DBT's with esoteric amps versus cheap $100 Sony receivers. All I can say is the moderators must have really tweaked the heck out of those esoteric amps to remove all the garbage one usually gets in output sound. I'd also venture to say they were playing the units at extremely low levels, because distortion rears it's ugly head quickly with peaks in treble, as well as bass. It's very noticable with classical music when an amp is underpowered. Some of those tests are useless because the volume output has to be so low to level match, and some of the very low spl speakers (83dB at 4 ohms) won't even hiccup with these entry level receivers. It's like racing a Chevette against a Corvette at 30mph, while you must maintain the exact same speed and start through the race. They tie. Why bother? All bias has been removed. Horay, what have we proved?

 

[mulester7]

Any amplifier you get, that is a good amp, is going to sound better. Unless the amp is being driven beyond its limits (which you are doing now using the receivers amp) you aren't going to notice a difference in the sound. Most of the tonal qualities are introduced in the preamp section

....but Mac, if you don't overdrive the amp, and just sip off huge headroom, what do you hear over an amp with 50 per?....which end of the speaker's response do you notice the most?....serious watts now....ok, less than reference levels, but FULL, and not too far below reference....

 

[Nick250]

Please explain all the bias you would remove when comparing the "perception equation."

I still stand by my claim that even you could hear a difference between this Insignia unit at 30 watts and a McIntosh 1201 power amp running through a Yamaha RXV2500 at 30 watts (in stereo and through some Paradigm 8 ohm towers.

I would like to hear more about such a test. I think it would be interesting to all. I have read about DB testing between the $5000 separates and the $500 receiver and in every case the subjects were not able tell the difference between the two. I have not read of any tests where the reverse is the outcome. This of course is the kind of test that Buckeye mentions where the speakers are each being fed an arbitrary amount of power like the 30 watts he mentions. Perhaps, in the interest of enlightenment Clint would conduct such a test.

 

[MacManNM]

Does this mean that if I biamp (unstrapped @ 8ohms) as opposed to one single channel (strapped @ 4ohms) the sensitivity would be 90dB for the high and low freq. drivers. If true, then biampping seems to be better than going with one channel strapped @ 4ohms.

It really depends on the amplifier. One with a high current design that can drive a low Z load is going to perform the same as Bi-amping with lesser units.

 

[MacManNM]

That would depend on the voltage used, right? So if it is at 2 watts input, 2.83V, you will still have lots of power.

I am looking into the impedance question.

It's 3 db.

 

[MacManNM]

....but Mac, if you don't overdrive the amp, and just sip off huge headroom, what do you hear over an amp with 50 per?....which end of the speaker's response do you notice the most?....serious watts now....ok, less than reference levels, but FULL, and not too far below reference....

Absolutely, headroom is important. This is why your idea has so much merit. I always say you should have more power than your speakers will handle. Nice clean power will improve the sound dramatically even at moderate listening levels.

 

[AVRat]

Bi-amping conundrum

The Rti 12s would appear to be comprised of the Monitor 40 system with the addition of the woofer section. The Monitor 40s have a power rating of 125W, while the Rti 12s are rated at 500W. The Rti 12s upper section is alleviated of frequencies below 120 Hz which we can now assume handles about 100W. Given this, it would appear that the woofer section handles 400W. At the ratio of 1:4, and with the Yammy providing 130W, it looks like you would need an amp rated at about 500W for the woofer section to provide proper balance.

I would still go with a good 2-channel amp to power the whole speaker and let the crossover network take care of appropriate power distribution..