Best amp for Polk Rti series and Yam 2500

[Buckeyefan 1]

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..

AVRat,
Good point. Way to break it down. He still has the issue with brightness, but with that setup, can slide in an eq to tame the highs. An eq would be perfect in that sense because he can get rid of the muddiness, and bump the lowest frequencies for some extra bass.

 

[AVRat]

I don't know what I was thinking!

Let's try this again.

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. Given this, it would appear that the woofer section handles 375W. At the ratio of 1:3, and with the Yammy providing 130W, it looks like you would need an amp rated at about 400W for the woofer section to provide proper balance.

 

[mtrycrafts]

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?

Which DBTs are you talking about? Which exotic amps?
You should not make assumptions and believe them to be facts not in evidence.
Perhaps your protocol is misleading your perceptions?

Actuall, it is not like racing a Chevy against a Corvett. It mystifies me when audio folks try to use a car analogy. Please, you can do better.

 

[mtrycrafts]

Let's try this again.

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. Given this, it would appear that the woofer section handles 375W. At the ratio of 1:3, and with the Yammy providing 130W, it looks like you would need an amp rated at about 400W for the woofer section to provide proper balance.

Do you know what distoprtion that speaker or any speaker, minus the Velo servo , will have at 125 watts or more? You may want to ask a few speaker makers about them


Oh, you can stand up to 10% in a sub. Don't try that with the rest of the bands

So, don't be so enamored with the power rating of speakers.

 

[Buckeyefan 1]

Which DBTs are you talking about? Which exotic amps?
You should not make assumptions and believe them to be facts not in evidence.
Perhaps your protocol is misleading your perceptions?

Actuall, it is not like racing a Chevy against a Corvett. It mystifies me when audio folks try to use a car analogy. Please, you can do better.

The ones you've posted and referenced here at Audioholics. I spent an evening or two reading quite a few of your posts (in the dark ages). You should go back and read them, too.

 

[MacManNM]

Do you know what distoprtion that speaker or any speaker, minus the Velo servo , will have at 125 watts or more? You may want to ask a few speaker makers about them


Oh, you can stand up to 10% in a sub. Don't try that with the rest of the bands

So, don't be so enamored with the power rating of speakers.

Get a clue. He might be wrong but don't quote it if you aren't going to answer it.

 

[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.

You really think this?
The Z is frequency dependent, hence the Z at the low frequency will be that of the low driver, regardless of bi amping or not, get it? Same goes for the next set of drivers, right? Got it???

 

[MacManNM]

You really think this?
The Z is frequency dependent, hence the Z at the low frequency will be that of the low driver, regardless of bi amping or not, get it? Same goes for the next set of drivers, right? Got it???

It can't go any lower than the DCR of the circuit. Unstrapped the low end is 7.9 ohms, and the upper end is 8.2 ohms. Strapped together the circuit is 4.03 ohms. Now, the impedance can't be any lower than 7.9, and 8.2 ohms unstrapped in Bi-amped mode. It can only go up from there.

 

[Buckeyefan 1]

It can't go any lower than the DCR of the circuit. Unstrapped the low end is 7.9 ohms, and the upper end is 8.2 ohms. Strapped together the circuit is 4.03 ohms. Now, the impedance can't be any lower than 7.9, and 8.2 ohms unstrapped in Bi-amped mode. It can only go up from there.

Mtry, Mac is correct. I don't know where you are getting this information. Do you have a set of Polk RTi towers where you've run tests?

 

[mtrycrafts]

It can't go any lower than the DCR of the circuit. Unstrapped the low end is 7.9 ohms, and the upper end is 8.2 ohms. Strapped together the circuit is 4.03 ohms. Now, the impedance can't be any lower than 7.9, and 8.2 ohms unstrapped in Bi-amped mode. It can only go up from there.

Have you seen the impedance curve on this speaker, not its DC resistance, over the entire audio band? Maybe Stereopile has it plotted. They like to measure it. Check out another 4 ohm nominal speakersee where the Z is.

What happens when you drive the speaker with the low band? What Z does the amp see? It ain't 4 ohms.

What Z does the amp see when you drive the high end? It ain't 4 ohms.

 

[mtrycrafts]

Mtry, Mac is correct. I don't know where you are getting this information. Do you have a set of Polk RTi towers where you've run tests?

No, I don't have that speaker available. But Z is frequency dependent. Nominal Z is just that, nominal. Check out the low band Z and the high band Z. That is what the amp sees.
What happens when you only have the low band energized, or the high band?

It is not two resistors in there in there.

 

[MacManNM]

Have you seen the impedance curve on this speaker, not its DC resistance, over the entire audio band? Maybe Stereopile has it plotted. They like to measure it. Check out another 4 ohm nominal speakersee where the Z is.

What happens when you drive the speaker with the low band? What Z does the amp see? It ain't 4 ohms.

What Z does the amp see when you drive the high end? It ain't 4 ohms.

The whole point here is that the Z can't be any lower than the DCR, so it is going to be 7.9 ohms or above on the bass at all times.

 

[mtrycrafts]

The whole point here is that the Z can't be any lower than the DCR, so it is going to be 7.9 ohms or above on the bass at all times.

Yes. So will it be when bi-amped. Z will be higher than the DCR. What is gained? Insane high levels of spl

 

[PENG]

Yes. So will it be when bi-amped. Z will be higher than the DCR. What is gained? Insane high levels of spl

As Mac said, impedance of a circuit cannot be lower than its d.c. resistance. How can it be lower?

 

[MacManNM]

Yes. So will it be when bi-amped. Z will be higher than the DCR. What is gained? Insane high levels of spl

That was one of the founding points here. These receivers can't drive the low Z loads, the Polks specs are wrong, and an external amp will make them sound better.

Your opinion of insane levels is obviously wrong. In a previous post I believe I went through the levels at the listening position taking into consideration the distance and sensitivity. This, like most other facts presented, you ignore, citing your interpretation of “insane levels”, and “who would do that”, well, some of us like it loud and clean.

There is merit for people to upgrade their amplification, dynamic range being one of them. Because you have some phobia of amplifiers, please keep it to yourself. Everyone here knows your affinity for quoting any and all pubs, along with your opinion that everything sounds identical. Let us enthusiasts live our wonderful lives, with our belief that our equipment was bought because we liked the sound of it better than brand X.

 

[mtrycrafts]

These receivers can't drive the low Z loads, the Polks specs are wrong, and an external amp will make them sound better.

How so? How are they wrong? Maybe they can be convinced to publish to correct ones? Or, is it that you only measure the DCR???

Your opinion of insane levels is obviously wrong.

Oh, 111dB spl is not insanely loud? That is well above reference level, and it is at 25 watts.

In a previous post I believe I went through the levels at the listening position taking into consideration the distance and sensitivity.


Yes, you did. So, it is close to insanity then, especially since it is only at 25 watts?


There is merit for people to upgrade their amplification, dynamic range being one of them. Because you have some phobia of amplifiers, please keep it to yourself.

No, I have no phobia, I just have a hard time with myths, audio voodoo, urban legends, unnecessary expenditures based on these myths.


along with your opinion that everything sounds identical.


You cannot even get it right, what my opinion is. How can you get anything right?



Let us enthusiasts live our wonderful lives, with our belief that our equipment was bought because we liked the sound of it better than brand X.

You are not prevented from believing anything you want. I want others to get better info than a belief based one. Then they can choose. without that, there is no choice.

 

[mtrycrafts]

As Mac said, impedance of a circuit cannot be lower than its d.c. resistance. How can it be higher?

HUH? Cannot be higher? Check a speaker impedance curve. Frequency dependent unlike a resitive load. Stereopile has some curves for speakers.

 

[MacManNM]

How so? How are they wrong? Maybe they can be convinced to publish to correct ones? Or, is it that you only measure the DCR???

Have you ever even used an Ohmmeter to measure the resistance of a driver or speaker? I have, and when they are rated at 8 ohms, they measure 8 ohms or slightly less. Just to let you know units like the Denon 3805 can’t drive a 4-ohm load. They are current limited, at least that’s what their tech support told me.



In a previous post I believe I went through the levels at the listening position taking into consideration the distance and sensitivity.

Yes, you did. So, it is close to insanity then, especially since it is only at 25 watts?

HUH? To achieve 96db @ 4meters with a speaker that has a sensitivity of 87db (like the Polks), you need 128 watts. Insanity, I know. I’m sure you will say that isn’t a realistic listening level or distance.

You cannot even get it right, what my opinion is. How can you get anything right?

Your opinion? You actually have one? You have made good points in the past, and your knowledge base is broad. Quit believing everything you read and chill dude.

 

[MacManNM]

HUH? Cannot be higher? Check a speaker impedance curve. Frequency dependent unlike a resitive load. Stereopile has some curves for speakers.

The man made an error, he meant lower. You know that, yet you insist on instigating.

 

[PENG]

HUH? Cannot be higher? Check a speaker impedance curve. Frequency dependent unlike a resitive load. Stereopile has some curves for speakers.

I meant it couldn’t be lower; I made a typo in my second sentence (it has been edited).

I am not saying that the speaker circuit is a resistive load. It is a complex load that contains resistive, inductive, and capacitive components. You are right, the inductive and capacitive components of the speaker load are frequency dependent but its resistive component (such as the resistance of the coil) is not. If you measure it with an ohmmeter, you get its resistance, or D.C.R., because the ohmmeter's measuring signal is D.C., i.e. 0 Hz. If it is found to be say X ohms, then the resistance of the circuit is X ohms regardless of the frequency of the signal. Skin effect does make the resistance somewhat frequency dependent but it will be negligible, and in any case, will make it higher, not lower.