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Separate Amplification Upgrade Query: Which Way Would YOU Go? - Page 4

post #91 of 213
Quote:
Originally Posted by Audiophile2k View Post

.We do agree running them full range will eat up much more amplifier power if you intend to push them to the limit (something the OP has already stated he doesn't do)....

Correct. He doesn't do that now, nor could he with his entry level Onkyo. What he asked was if a power amp would, I paraphrase here. 'really make them sing.'

Yes, it would.

50,000 watts, huh. I don't know about that. My amp can only do 600 at 8ohms, 1000 at 4.

Many times I've had friends over for music sessions, and they always ask what kind of sub I have. They can't believe it when I tell them the sub isn't running. I've even had guys put their fingers on the sub driver as they just wouldn't believe me.

A caveat. I don't own RTi12s. I have their older brother, RTi150s. Very similar speakers, so I made the leap that the 12s would perform similarly.

For testing, I fed a variety of low frequency pulses. 20 hz. 85db at MLP. Almost 2 meters from the drivers. Does the room contribute? I'm sure it does. My theater is small, 12x14.

My speakers are 8 years old and still going strong. I did need to buy new crossovers, old ones burned up (that's what I get for jamming out to Crazy Horse.)

Happy Thanksgiving everyone.

Jeff
post #92 of 213
Without knowing if the signal was clean at 85db (meaning the spl could have been an artifact of distortion at a higher frequency) lets look at your best case scenario even in your small room. If it took 600W to get to 85db the breakdown is as follows.
88db - 1200w (already over double the amount of power the Polks are rated for)
91db - 2400w
94db - 4800w
97db - 9600w
100db - 19200w

So, given the best case scenario of a small room, and not questioning if your data of 85db was a pure signal and not distortion, it would take an amp of 19,200 watts to get the 100db mark at 20hz. (still below reference level) For speakers that will blow when you feed them over 500w, it is not looking too good for the drivers. There are plenty of subs capable of reference output (and even lower) in that size room in the $500 - $600 range. Not only that, you could easily drive your Polks with a much smaller amp (like in any AVR) once you relieve that strain of trying to produce the lower end where it is straining and surely distorting to an extreme degree. Seems the sub is a much wiser place to spend your money than external amps.
post #93 of 213
Thread Starter 
Quote:
Originally Posted by Hopinater View Post

It's a great sub in my opinion. I can't help but smile when I hear it regardless of whether I'm listening to music or watching a movie.  

Thanks. I have it on my "consider" list. wink.gif
post #94 of 213

No problem.

post #95 of 213
Thread Starter 
Now, you see, all...

It is Jeff's post and many like it that lead me to believe I MUST feed my RTi12s with muscle, separate amplification -- here's where I go back around in circles again...mad.gifmad.gif

Let's straighten some stuff out (because according to Jeff, I NEVER will achieve the "right amount of SPL for these RTi12s with my 'entry level Onkyo'") -- I do NOT find myself needing to push the volume of my current system beyond what I normally listen at. We are getting NO fatiguing, shrillness, clipping or distortion at the comfortable SPL levels we currently run. The RTi12s are NOT -- I repeat NOT -- being run FULL RANGE off the Onkyo 605, instead crossed-over at 60Hz to a sub...

I was advised by Polk's customer support -- one "Eric Wong" who was very helpful -- several times that my current AVR is perfectly fine for driving the RTi12s especially since I'm passing off low bass duties to the sub...also, I was advised, by keeping my crossover at 60Hz for the 12s, this allows the rather large tower speakers to "flex some of their muscles" WHILE still giving my sub a good workout with all content 60Hz and below.

The reason I started the thread was to inquire of what the best route would be to do IF I decided to experiment with feeding my RTi12's some external juice...
post #96 of 213
Thread Starter 
Now, let's get back to this "line level converter" option for my 605...

Why would this be advised against? Wouldn't this "convert" the speaker level outputs to line level/pre outputs so the signals can be passed to an amp? Do these devices introduce distortion or problems of any kind?

I would think that would be one solution to dealing with the issue of my AVR not boasting preamp outputs...
post #97 of 213
Thread Starter 
Quote:
Originally Posted by duc135 View Post

Sorry if I gave you the impression that I felt you were ignoring my advice. To me there is a difference between ignoring and foregoing. I know you have acknowledged my posts, but are still leaning towards external amplification. That's perfectly fine as it's ultimately your system and your money. You are free to do as you please. I just want to provide the scientific numbers as I understand them with my anecdotal experience thrown in. You have been nothing, but gracious with our posts.

Oh, no, I'm not trying to be foregoing either; just trying to weigh all the options -- I am glad that you replied in kind to the way I have been answering all you guys with all your help...that is greatly appreciated. smile.gif
Quote:
That is correct, but to upgrade the AVR just for pre-outs that you may not use at this point is not the best use of your budget IMO. Heck, I can even bring over one of my 4311s and you can test out Audyssey MultEQ XT32 if you want to hear if it will make an improvement in your setup. You are also correct that you can also use a converter with your existing AVR, but that is not optimal. The less things processing the signal in the chain the better. It's an option for the budget strapped which you don't seem to be.

Thank you for the offer, duc; I shall indeed consider it. Can I get some more of your thoughts on these line level converters?
post #98 of 213
Quote:
Originally Posted by Audiophile2k View Post

Seems the sub is a much wiser place to spend your money than external amps.

No, not in my case. Bought the amp second hand, and it cost about the same as the Polks.

I essentially have three subs in my room. 2 have 600 watt amps, the third a 250 watter. It has taken some extensive experimentation, moving the third sub around the room, adjusting levels, ect. But I'm fairly happy with the sound as it is now. I'd like to try a really heavy duty sub, like a Submersive or some such at some point, but that might be overkill for a small room. Maybe 3 cheap subs ($400-$600 each) would sound better. Doubt it.

As for distortion and the Polks. Nah. Let's face it. They're only using 5 watts most the time. wink.gif The separate sub is more prone to distortion. The Parts Express amp sux.

Yes, I could run the Polks crossed over at 80hz, then buy a couple $600 subs. But why? My Polks are internally crossed over at 80hz, so I'd be using them as bookshelves. Not for me.

As for recommendations to the OP. Getting a decent sub is certainly a good idea. And while I wasn't recommending anything, just sharing my experience with similar Polk speakers - if he wants to run his 12s full-range, which is after all, what they're designed for, then I don't think I'm out of line recommending he replace the aging under-powered Onkyo with a separate power amp.
post #99 of 213
Quote:
Originally Posted by .jss designs View Post

To answer the original question, yes the Polk RTi12 speakers performance can benefit from a more powerful amplifier. The 12s are a large, heavy (80lbs. Ea.) full-range speaker. They are a 3 -way design with 6 drivers: three 7" woofers, two 5.25" midrange, and a 1" tweeter. The woofers are crossed over at 120hz to the midrange, which are crossed at 1800hz to the tweeter. Polk rates the speaker at 30hz at -3db. In real world use, they can hit 100db at 20hz if driven with a high current, high power amp. They can out-perform many so-called subwoofers on the market.

The 3 woofers have a surface area greater than a 12 inch sub.

Wow, just wow! Where to start with this one?

If we're going just on weight and size of the bass drivers, I've got the Polks beat and can't tell the difference between the internal amps of my receiver and my 600W/CH external amp. My speaker has three 8" bass drivers and weighs nearly twice as much as the Polks. There is no way on god's earth any 7" bass drivers in a satellite speaker can come close to comparing to a real sub of any size regardless of how much power you give it. My speaker has three 8" drivers with an F3 of 23Hz anechoic. The three 8" drivers have a surface area equal to a single 14" driver. Even though the bass section of my speaker is ported, no way can it compete with even a single one of my 10" sealed subs given the same amount of power. That's a total of six 8" drivers versus a single 10" driver.

Subwoofer drivers are designed for massive air movement. This means very powerful motors and high excursion drivers that can handle copious amounts of power. Unless you have a tower of many multiples of small bass drivers, there is no comparison.

Quote:
Originally Posted by .jss designs View Post

You'd never consider buying a 80-90 watt subwoofer.

A well designed, horn loaded 12" sub using only 100W can lay waste to any full range tower with 500W of power in the bass frequencies. Take a look at the horn loaded subs that lilmike on this forum has designed for a few hundred dollars in parts. So yes, I would consider buying a 90W subwoofer. It's not just about power. When considering bass, it's all about air displacement.

Quote:
Originally Posted by .jss designs View Post

Now, if you aren't going to run them full range, and you want to use a subwoofer for 80hz and lower, a power amp is not necessary.

I can agree with you here.

Quote:
Originally Posted by .jss designs View Post

But if you really want to know what the 12s can do, you need to run them full-range, and you need much more power than your Onkyo can produce.

Please explain how a speaker that is using, at most, 50W will sound better if powered by an external amp. No anecdotal testimonials please. This is, after all, A/V Science forum.
post #100 of 213
Quote:
Originally Posted by .jss designs View Post

Yes, I could run the Polks crossed over at 80hz, then buy a couple $600 subs. But why? My Polks are internally crossed over at 80hz, so I'd be using them as bookshelves. Not for me.
 

Interesting thoughts but have you tried a good subwoofer? There's a HUGE difference between towers trying to get down below 30hz with anemic output and a Outlaw LFM-1EX, or a SVS PB12 or a PSA XV15 digging down below 20hz at close to reference level power.

 

No way in the world a tower, even one with three woofers running amped to a mono block can match the 15'' driver and 500 watt amp of a XV15, it just can't, it's not made to. And its the subwoofer that will make the difference from watching a movie with a decent sound system to watching a movie and experiencing the theatre experience, the way the movie was meant to be experienced. 

 

Don't forget, most speakers are primarily designed for music and they do that job very well. But they aren't designed to carry the LFE of today's movies (IMO).


Edited by Hopinater - 11/27/13 at 8:01pm
post #101 of 213
Quote:
Originally Posted by Audiophile2k View Post

Without knowing if the signal was clean at 85db (meaning the spl could have been an artifact of distortion at a higher frequency) lets look at your best case scenario even in your small room. If it took 600W to get to 85db the breakdown is as follows.
88db - 1200w (already over double the amount of power the Polks are rated for)
91db - 2400w
94db - 4800w
97db - 9600w
100db - 19200w

So, given the best case scenario of a small room, and not questioning if your data of 85db was a pure signal and not distortion, it would take an amp of 19,200 watts to get the 100db mark at 20hz. (still below reference level) For speakers that will blow when you feed them over 500w, it is not looking too good for the drivers. There are plenty of subs capable of reference output (and even lower) in that size room in the $500 - $600 range. Not only that, you could easily drive your Polks with a much smaller amp (like in any AVR) once you relieve that strain of trying to produce the lower end where it is straining and surely distorting to an extreme degree. Seems the sub is a much wiser place to spend your money than external amps.

I presume that the above is to make a point via hyperbole because getting 85 dB out of typical 90 dB/W speakers takes about 1 watt or less.

Peak reference level is 105 dB, which then takes about 100 watts.
post #102 of 213
Quote:
Originally Posted by IntelliVolume View Post

Now, let's get back to this "line level converter" option for my 605...

Why would this be advised against? Wouldn't this "convert" the speaker level outputs to line level/pre outputs so the signals can be passed to an amp? Do these devices introduce distortion or problems of any kind?

Line level converters are just resistive pads that add no distortion as long as the resistors keep on being resistors.

However the resistors involved usually include cheap potentiometers that can become noisy and/or intermittent over time. YMMV.
Quote:
I would think that would be one solution to dealing with the issue of my AVR not boasting preamp outputs...

Been there done that but I rolled my own.

When I roll my own I either use fixed-value resistors with values that are designed for the specific application, or I use high quality $15 potentiometers.

I think that these products get a bad rap because they carry with them implications related to gain staging. As soon as you add another gain control it has to be set properly and that is not always trivial.
post #103 of 213
Quote:
Originally Posted by Hopinater View Post

Quote:
Originally Posted by .jss designs View Post

Yes, I could run the Polks crossed over at 80hz, then buy a couple $600 subs. But why? My Polks are internally crossed over at 80hz, so I'd be using them as bookshelves. Not for me.

 
Interesting thoughts but have you tried a good subwoofer? There's a HUGE difference between towers trying to get down below 30hz with anemic output and a Outlaw LFM-1EX, or a SVS PB12 or a PSA XV15 digging down below 20hz at close to reference level power.

No way in the world a tower, even one with three woofers running amped to a mono block can match the 15'' driver and 500 watt amp of a XV15, it just can't, it's not made to. And its the subwoofer that will make the difference from watching a movie with a decent sound system to watching a movie and experiencing the theatre experience, the way the movie was meant to be experienced. 

Agreed. Bass comes from speaker drivers via 2 dimensions, cone area being just one of them. The other is Xmax. Xmax tends to be limited by cone diameter, which means that its hard to find 7" woofers with Xmax much beyond 7 mm or so. In contrast 15 inchers with 20+ mm Xmax ( about 3 times the Xmax, and about 4 times the cone area for 12 times the displacement) just about grow on trees.
Quote:
Don't forget, most speakers are primarily designed for music and they do that job very well. But they aren't designed to carry the LFE of today's movies (IMO).

We've had recordings that needed a subwoofer to sparkle for decades before HT was even a twinkle in Ray Dolby's eye. ;-)

Specifically the Telarc 1812 and Battle Symphony LPs (ca. 1979) and a well set up tone arm with a V15 can easily justify having a good sub.

My first sub was a 14 cubic foot box with an 18" reconed Cerwin Vega "Earthquake" (the movie) bass driver. F3 was 20 Hz and it did things that were pretty impressive for ca. 1977.
post #104 of 213
Quote:
Originally Posted by Hopinater View Post

No way in the world a tower, even one with three woofers running amped to a mono block can match the 15'' driver and 500 watt amp of a XV15, it just can't, it's not made to. And its the subwoofer that will make the difference from watching a movie with a decent sound system to watching a movie and experiencing the theatre experience, the way the movie was meant to be experienced. 

Don't forget, most speakers are primarily designed for music and they do that job very well. But they aren't designed to carry the LFE of today's movies (IMO).

Not sure where I said that it would. I have a HSU VTF3 that I use for movies and my .1 when running multichannel music. It's bass response is far more impressive than my Polks. Floor shaking. But I prefer my Polks for 2 channel music. I've run 2.1 with the sub, but it's not my preference.

I've tried running 3 different AVRs with the Polks. All of them go into protect mode. The last was an Elite 59txi, a powerful well respected unit, if somewhat out dated, in may ways. I had an HK325 that fried itself, or at least the right power transistor. Currently running a R972 Sherwood Newcastle. Trinnov has done a remarkable job integrating my sub and the Polks - which I run full-range....

My point was the Polks will benefit from a power amp if run full-range, based on my experience. Not that it's a substitute for a XV15.
post #105 of 213
Quote:
Originally Posted by IntelliVolume View Post

Oh, no, I'm not trying to be foregoing either; just trying to weigh all the options -- I am glad that you replied in kind to the way I have been answering all you guys with all your help...that is greatly appreciated. smile.gif
Thank you for the offer, duc; I shall indeed consider it. Can I get some more of your thoughts on these line level converters?

The way I see it is that any time you have to process a signal, there is the potential for altering the original signal in one way or another. These converters are just another device in the chain that processes the signal. Will the changes be audible? I don't know, but the effects are cumulative, so less is more in this case.

I have a preference for getting the closest reproduction of sound to that what is contained in the recording. This is why I selected the products that I did. My speakers measure nearly flat across the frequency range, I treated my room as best I could, I run Audyssey to deal with spikes and nulls introduced by my room, I use REW and external mic to measure frequency responses before and after and I have a sub system that can reproduce as much of the LFE frequencies as I feel is reasonable to achieve.

Of course, everything must be considered to keep within your budget. Decisions cannot be made in a vacuum.
post #106 of 213
I don't post in threads like this to get into petty arguments, I only do it to try to explain the objective science (proven repeatable facts) vs. some of the anecdotal "magic" that some people insist on. Everyone is of course entitled to believe what they want. The old saying is "you are entitled to your own beliefs, but not your own facts". Of course many things in this hobby are subjective, but many are not. My goal in this thread was at first to help the OP, then to clear up some misinformation posted by someone else. I would never try to tell someone else what sounds best to them, but I can present facts that sometimes contradict what they believe. What they choose to do with that info is of course entirely up to them.

It is very frustrating however when several of us have taken the time to break down an issue and explain in detail WHY we are recommending what we are recommending, only to have someone come along posting false claims that only further confuses the OP. I don't want to sound like I'm picking on Jeff, but man, your posts are all over the place. You made some claims that I showed you absolutely couldn't be true, one minute you say the speakers don't need subs, the next you say you have 3 subs in your system...one post says he needs an external amp because of his wimpy AVR, the next says he doesn't need to do that if he isn't running his speakers full range....etc, etc. You have every right to post here with your experience with your speakers. But please at least 1) Try to be consistent with your OPINIONS and 2) double check your FACTS before you post and 3) don't make up stuff out of thin air. It will make this place much less confusing for the people who come here with their problems and who are looking for real info.
post #107 of 213
Quote:
Originally Posted by Audiophile2k View Post

I don't want to sound like I'm picking on Jeff, but man, your posts are all over the place. You made some claims that I showed you absolutely couldn't be true, one minute you say the speakers don't need subs, the next you say you have 3 subs in your system...one post says he needs an external amp because of his wimpy AVR, the next says he doesn't need to do that if he isn't running his speakers full range....

I disagree with your interpretation of my posts. Sorry.

I'm mostly a lurker, so can't do the fancy quoting some more experienced folks do, but this is what I've said from the outset:

The RTi12s will benefit with more power. They are capable of very impressive bass if run full range, based on my experience with my similar speakers. Yes, I have 3 subs, two of them are in my towers. Sorry you didn't understand that.

Most would be able to infer that if someone states, "If you wish to run your speaker full-range you need a more powerful amp" that conversely, "If you are not running them full-range you don't need a more powerful amp."

And I'm not the only one that found your 'science' to be a nothing more than hyperbole.

I'm going to go listen to my Polks. Loud, and bub, they'll be drawing more than 5 watts.

Sheesh.
post #108 of 213
Quote:
Originally Posted by arnyk View Post

I presume that the above is to make a point via hyperbole because getting 85 dB out of typical 90 dB/W speakers takes about 1 watt or less.

Peak reference level is 105 dB, which then takes about 100 watts.

His claim was 85db @ 20hz. He had also claimed in another post it could output over 100db at 20hz. The post was to explain in detail why that was not possible with that speaker.
post #109 of 213
Quote:
Originally Posted by .jss designs View Post

.

I've tried running 3 different AVRs with the Polks. All of them go into protect mode. The last was an Elite 59txi, a powerful well respected unit, if somewhat out dated, in may ways. I had an HK325 that fried itself, or at least the right power transistor. Currently running a R972 Sherwood Newcastle. Trinnov has done a remarkable job integrating my sub and the Polks - which I run full-range....

The fact that you run the RTi12s full range probably explains why you are plagued with AVRs that go into protect mode and are very critical of bass management.

Please refer to http://www.soundstagemagazine.com/measurements/polkaudio_lsi9/

The LSI9s are not floor standers but they do have dual woofers. I'm trying to illustrate the fact that speakers have distortion that often starts growing pretty fast several octaves above their bass rolloff point.

The Lsi9s are rated down to 38 Hz by Polk, but their distortion starts rising as high as 200 Hz.

Now lets look at a cheap but good 12" sub

http://www.data-bass.com/data?page=system&id=47&mset=45



you can see that even a cheap 12" sub has low distortion down to 40 Hz and 110 dB SPL while the 2-woofer Polk is in trouble starting at 200 Hz and 90 dB SPL.

No knock on the Polks intended and I'd expect your far larger Polk to do much better, but these are typical trends.
post #110 of 213
Quote:
Originally Posted by IntelliVolume View Post

Now, you see, all...

It is Jeff's post and many like it that lead me to believe I MUST feed my RTi12s with muscle, separate amplification -- here's where I go back around in circles again...mad.gifmad.gif

Let's straighten some stuff out (because according to Jeff, I NEVER will achieve the "right amount of SPL for these RTi12s with my 'entry level Onkyo'") -- I do NOT find myself needing to push the volume of my current system beyond what I normally listen at. We are getting NO fatiguing, shrillness, clipping or distortion at the comfortable SPL levels we currently run. The RTi12s are NOT -- I repeat NOT -- being run FULL RANGE off the Onkyo 605, instead crossed-over at 60Hz to a sub...

I was advised by Polk's customer support -- one "Eric Wong" who was very helpful -- several times that my current AVR is perfectly fine for driving the RTi12s especially since I'm passing off low bass duties to the sub...also, I was advised, by keeping my crossover at 60Hz for the 12s, this allows the rather large tower speakers to "flex some of their muscles" WHILE still giving my sub a good workout with all content 60Hz and below.

The reason I started the thread was to inquire of what the best route would be to do IF I decided to experiment with feeding my RTi12's some external juice...

the issue with jeff's post is it is highly subjective. the point remains, if you are not experiencing clipping issues at your desired spl levels in your room with the 12's then additional power is not required for you to get the most out of your 12's in your room.

the mumbo jumbo about speakers "opening up" or singing" with more power reserves avaialble is just that - mumbo jumbo. 5-80 watts from your avr will sound exaclty like 5-80 watts from a power amp. the amp has advantage in that it has the potential to get louder and remain clean, where as the avr could run out of clean power if you push the system to high(er) spl levels. but in your case, you have stated many times that you are not clipping or the like so the actual benefit for you is slim.

Now would i not encourage you to get a power amp? No, I think it is good insurance to have the extra power in those few and far between moments of "just in case". For me, using 2 different avr's with my speakers i managed to push the avr's to a high level of distortion which killed my tweeters - obviously i was not able to achieve my desired spl levels in my room with my speakers. adding my power amps - which gave me appx 3-4dB headroom over my avr allowed me to push my system to my desired spl levels cleanly.

however your best bet in my opinion is to try a higher end avr then the one you currently have and see what the performance is like before committing to an additional power amp. something like a denon x4000 or onkyo 818 or 929 can potentially be worlds apart for you from what you currently have - mainly due to the inclusion of xt32 (i know you mentioned you dont use audyssey - but if you get one of these avr's i highly recommend you try it before dismissing it). Also like others have said, a really good subwoofer can make worlds of difference to you. another thing to consider is room treatments.

good avr with xt32, good subwoofer and a decently treated room will provide many many more positive sonic benefits over a power amp. power amps do have their place though.
post #111 of 213
Quote:
I disagree with your interpretation of my posts. Sorry.
I am also sorry if I'm being rude about this...it is not my intention. I could have very well misunderstood your intentions in a few posts, just like Arnold misunderstood my post in reply to you. Below is a narrowed down example of some of the things you've stated to the OP after knowing his exact situation, and his reaction. This is what I found so frustrating. Sorry if I didn't express it well.
Quote:
What he asked was if a power amp would, I paraphrase here. 'really make them sing.'

Yes, it would.
Quote:
Polk rates the speaker at 30hz at -3db. In real world use, they can hit 100db at 20hz if driven with a high current, high power amp. They can out-perform many so-called subwoofers on the market.



And the end result
Quote:
It is Jeff's post and many like it that lead me to believe I MUST feed my RTi12s with muscle, separate amplification -- here's where I go back around in circles again...mad.gifmad.gif

Let's straighten some stuff out (because according to Jeff, I NEVER will achieve the "right amount of SPL for these RTi12s with my 'entry level Onkyo'") -- I do NOT find myself needing to push the volume of my current system beyond what I normally listen at. We are getting NO fatiguing, shrillness, clipping or distortion at the comfortable SPL levels we currently run. The RTi12s are NOT -- I repeat NOT -- being run FULL RANGE off the Onkyo 605, instead crossed-over at 60Hz to a sub...

So if I understand your last post clearly, you are recommending, for his specific situation, that he does not need an external amp, and that adding a sub would do him the most good? Basically the same thing the rest of us have been saying?
post #112 of 213
Quote:
Originally Posted by arnyk View Post

The fact that you run the RTi12s full range probably explains why you are plagued with AVRs that go into protect mode and are very critical of bass management.

Please refer to http://www.soundstagemagazine.com/measurements/polkaudio_lsi9/

The LSI9s are not floor standers but they do have dual woofers. I'm trying to illustrate the fact that speakers have distortion that often starts growing pretty fast several octaves above their bass rolloff point.

The Lsi9s are rated down to 38 Hz by Polk, but their distortion starts rising as high as 200 Hz.

Now lets look at a cheap but good 12" sub

http://www.data-bass.com/data?page=system&id=47&mset=45



you can see that even a cheap 12" sub has low distortion down to 40 Hz and 110 dB SPL while the 2-woofer Polk is in trouble starting at 200 Hz and 90 dB SPL.

No knock on the Polks intended and I'd expect your far larger Polk to do much better, but these are typical trends.

Hi Arny,

The LSi9s are great little speakers. I've been trying to find a nice pair for quite awhile. But there's a big difference between them and my RTi150 floorstanders.

I've had a couple 'cheap' 12" ported subwoofers (Polk and a JBL) that my mains could outperform. I'm not talking measurements, since I never measured those subs, but in what I could hear in my room on general music reproduction at reference levels.

Some time back I got a better sub, HSU VTF. I like it when playing movies and multichannel music ( with a .1 mix.) But for 2 channel, I still prefer just the floorstanders.

But even the LSi9s might be better with a separate power amp over an AVR. They're 4 ohm speakers. Not sure an AVR could do the cannons justice, even on the LSi9s. smile.gif

Jeff
post #113 of 213
Quote:
Originally Posted by 67jason View Post

Quote:
Originally Posted by IntelliVolume View Post

Now, you see, all...

It is Jeff's post and many like it that lead me to believe I MUST feed my RTi12s with muscle, separate amplification -- here's where I go back around in circles again...mad.gifmad.gif

Let's straighten some stuff out (because according to Jeff, I NEVER will achieve the "right amount of SPL for these RTi12s with my 'entry level Onkyo'") -- I do NOT find myself needing to push the volume of my current system beyond what I normally listen at. We are getting NO fatiguing, shrillness, clipping or distortion at the comfortable SPL levels we currently run. The RTi12s are NOT -- I repeat NOT -- being run FULL RANGE off the Onkyo 605, instead crossed-over at 60Hz to a sub...

I was advised by Polk's customer support -- one "Eric Wong" who was very helpful -- several times that my current AVR is perfectly fine for driving the RTi12s especially since I'm passing off low bass duties to the sub...also, I was advised, by keeping my crossover at 60Hz for the 12s, this allows the rather large tower speakers to "flex some of their muscles" WHILE still giving my sub a good workout with all content 60Hz and below.

The reason I started the thread was to inquire of what the best route would be to do IF I decided to experiment with feeding my RTi12's some external juice...

the issue with jeff's post is it is highly subjective. the point remains, if you are not experiencing clipping issues at your desired spl levels in your room with the 12's then additional power is not required for you to get the most out of your 12's in your room.

+1 and the rest of your post that I deleted to shift the focus of my comments to the following.

I wanted to make the point that Jeff has a strong commitment to something that is arguably a bad idea, which is to use his L & R speakers in large mode while there is apparently a good Sub in play. It appears to me that his commitment to this questionable path has led to a bad taste in his mouth for AVRs, which I would have have too, perchance I saw any of mine go into protect mode.

It is stone impossible to accurately diagnose Jeff's situation from thousands of miles, but I can construct a believable story where Jeff has developed a taste for a certain amount of bass nonlinear distortion, which makes him reject potentially cleaner sound if he went solo with his sub. I'll be the first to point out that this speculation could be a pack of whoohey and his situation might be due to something completely irrelevant such as room acoustics.

At this point the problem I have with Jeff's comments is that they don't speak to me in a way that I can believe is how things have to be. Yeah they are highly subjective and go in a direction that disagrees with many of our experiences. But I think there are some true facts behind them, its just that the subjective color he seems to put on everything is obfuscatory, and isn't serving him well, whether he knows it or not.
post #114 of 213
Quote:
Originally Posted by .jss designs View Post

Quote:
Originally Posted by arnyk View Post

The fact that you run the RTi12s full range probably explains why you are plagued with AVRs that go into protect mode and are very critical of bass management.

Please refer to http://www.soundstagemagazine.com/measurements/polkaudio_lsi9/

The LSI9s are not floor standers but they do have dual woofers. I'm trying to illustrate the fact that speakers have distortion that often starts growing pretty fast several octaves above their bass rolloff point.

The Lsi9s are rated down to 38 Hz by Polk, but their distortion starts rising as high as 200 Hz.

Now lets look at a cheap but good 12" sub

http://www.data-bass.com/data?page=system&id=47&mset=45



you can see that even a cheap 12" sub has low distortion down to 40 Hz and 110 dB SPL while the 2-woofer Polk is in trouble starting at 200 Hz and 90 dB SPL.

No knock on the Polks intended and I'd expect your far larger Polk to do much better, but these are typical trends.

Hi Arny,

The LSi9s are great little speakers. I've been trying to find a nice pair for quite awhile. But there's a big difference between them and my RTi150 floorstanders.

Didn't I just say that?
Quote:
I've had a couple 'cheap' 12" ported subwoofers (Polk and a JBL) that my mains could outperform. I'm not talking measurements, since I never measured those subs, but in what I could hear in my room on general music reproduction at reference levels.

Some time back I got a better sub, HSU VTF. I like it when playing movies and multichannel music ( with a .1 mix.) But for 2 channel, I still prefer just the floorstanders.

But even the LSi9s might be better with a separate power amp over an AVR. They're 4 ohm speakers. Not sure an AVR could do the cannons justice, even on the LSi9s. smile.gif

Jeff

Congratulations, you completely missed my point. ;-)

Let me try it again.

Here is a speaker that you could only hope your RTi12s were:

Revel Ultimas - 2 8 inch woofers and $11k a pair.

Here is the Revel THD situation:



OK we moved the bad stuff down an octave, but the THD is still headed for the sky below 100 Hz.

It sounds crazy but it is possible that a $300 subwoofer could actually help the $11,000 Revels out if we set the Revels for "small".

And while we're at it, lets look at Jeff's Hsu VTF-15 in sealed mode:



For about 3 times the bucks you get one octave lower clean bass which come to think about it, ain't bad.

Barring some strangeness in room acoustics (which is why I have 2 subs) this baby could do even more for Jeff if we could get him to press the small button.
Edited by arnyk - 11/27/13 at 10:23pm
post #115 of 213
Quote:
Originally Posted by Audiophile2k View Post

So if I understand your last post clearly, you are recommending, for his specific situation, that he does not need an external amp, and that adding a sub would do him the most good? Basically the same thing the rest of us have been saying?

Yep. I agree with that. My response was to his questioning of whether a power amp would be beneficial to getting the most out the his RTi12s. Not that he necessarily needed one. Right now he's happy with the sound he is getting from them, and his AVR doesn't seem to be clipping or otherwise having issues, so no NEED for a power amp. But he is also not hearing what those speakers are fully capable of. And his wife probably would like it if he was. I can only crank my stuff when the better half is out shopping.

Jeff
post #116 of 213
Quote:
Originally Posted by .jss designs View Post

Quote:
Originally Posted by Audiophile2k View Post

So if I understand your last post clearly, you are recommending, for his specific situation, that he does not need an external amp, and that adding a sub would do him the most good? Basically the same thing the rest of us have been saying?

Yep. I agree with that. My response was to his questioning of whether a power amp would be beneficial to getting the most out the his RTi12s. Not that he necessarily needed one. Right now he's happy with the sound he is getting from them, and his AVR doesn't seem to be clipping or otherwise having issues, so no NEED for a power amp. But he is also not hearing what those speakers are fully capable of. And his wife probably would like it if he was. I can only crank my stuff when the better half is out shopping.

Jeff

the only thing that he is not hearing is how loud the speakers can potentially get. but a high loudness level does not appear to be one of intellivolumes goals. wink.gif
post #117 of 213
Quote:
Originally Posted by .jss designs View Post

Quote:
Originally Posted by Audiophile2k View Post

So if I understand your last post clearly, you are recommending, for his specific situation, that he does not need an external amp, and that adding a sub would do him the most good? Basically the same thing the rest of us have been saying?

Yep. I agree with that. My response was to his questioning of whether a power amp would be beneficial to getting the most out the his RTi12s. Not that he necessarily needed one. Right now he's happy with the sound he is getting from them, and his AVR doesn't seem to be clipping or otherwise having issues, so no NEED for a power amp. But he is also not hearing what those speakers are fully capable of. And his wife probably would like it if he was. I can only crank my stuff when the better half is out shopping.

If his existing power amp is not adding audible distortion, exactly what would a larger power amp do for him besides stuff like bragging rights and price of ownership?

Contrary to audiophile myth speakers can't sniff out power transformer weight at the other end of the speaker cable. No known such technical effect! ;-)
post #118 of 213
Quote:
Originally Posted by .jss designs View Post

The RTi12s will benefit with more power.

Yes, The RTi12s MAY benefit from more power, but not for the OP. He has already stated that he sits 12' from the speakers and they do not distort or clip being powered by his 90W/CH receiver. He does not turn them up to reference levels. He also crosses them over to a sub at 60Hz. The science is that he requires 128W to achieve reference level SPLs at 12' when running the speakers full range anechoic. That's 105dBs per speaker. Most people are not playing their speakers at 105dBs each. Let's assume a modest 3dBs boundary gain in his room. That reduces his power requirement by half. He is down to 64W to achieve reference. Since he already states he does not listen at reference let's assume he is only down 3dBs from reference and listens at 102dBs (which is still EXTREMELY loud to most people). A reduction of 3dBs is again half the power so now he's only drawing at most 32W from the receiver's amp section. Again, this is running the speakers full range. Knowing that most of the power draw from speakers is to reproduce the lower octaves and that the OP crosses those lower octave over to a sub then we can deduce that his speakers are drawing even less than 32W at -3dBs from reference levels.

Quote:
Originally Posted by .jss designs View Post

They are capable of very impressive bass if run full range, based on my experience with my similar speakers.

Impressive bass is all relative. My cousin feels his 100W peak power 8" Pioneer "subwoofer" is impressive in his 15K+ft^3 room.

Quote:
Originally Posted by .jss designs View Post

Yes, I have 3 subs, two of them are in my towers. Sorry you didn't understand that.



Let's clarify things here. You do NOT have three subs. Just because you have a 600W amp connected to your speakers, does not turn the bass drivers into subs. That's like saying a Smart car is a race car because someone put a 10000HP engine in it. Try taking that to the race track against a real race car and see what happens. As I and other posters explained previously, a sub's performance is about much more than how much power you give it and the surface area of the drivers. I can guarantee your six 7" drivers with the equivalent of two 12" drivers can't hold a candle next to my single 10" sealed sub with the same amount of power behind it. Bass drivers in satellite speakers have excursion measured in fractions of an inch. Subs are "usually" at least 1" P2P with 9some reaching 3" P2P. Subs are all about moving air; something your six 7" drivers simply cannot do nearly as well as a true subwoofer.

Sorry you didn't understand that.

Quote:
Originally Posted by .jss designs View Post

I'm going to go listen to my Polks. Loud, and bub, they'll be drawing more than 5 watts.

You should try measuring how much your speakers are actually drawing. I think you'd be surprised how little it really is. In a 12' x 14' room, I can't imagine it would take much power to make your ears cry uncle. What ever it is, it will be well within the capabilities of any decent receiver.
post #119 of 213
Thread Starter 
Quote:
Originally Posted by 67jason View Post

the issue with jeff's post is it is highly subjective. the point remains, if you are not experiencing clipping issues at your desired spl levels in your room with the 12's then additional power is not required for you to get the most out of your 12's in your room.

the mumbo jumbo about speakers "opening up" or singing" with more power reserves avaialble is just that - mumbo jumbo. 5-80 watts from your avr will sound exaclty like 5-80 watts from a power amp. the amp has advantage in that it has the potential to get louder and remain clean, where as the avr could run out of clean power if you push the system to high(er) spl levels. but in your case, you have stated many times that you are not clipping or the like so the actual benefit for you is slim.

Now would i not encourage you to get a power amp? No, I think it is good insurance to have the extra power in those few and far between moments of "just in case". For me, using 2 different avr's with my speakers i managed to push the avr's to a high level of distortion which killed my tweeters - obviously i was not able to achieve my desired spl levels in my room with my speakers. adding my power amps - which gave me appx 3-4dB headroom over my avr allowed me to push my system to my desired spl levels cleanly.

however your best bet in my opinion is to try a higher end avr then the one you currently have and see what the performance is like before committing to an additional power amp. something like a denon x4000 or onkyo 818 or 929 can potentially be worlds apart for you from what you currently have - mainly due to the inclusion of xt32 (i know you mentioned you dont use audyssey - but if you get one of these avr's i highly recommend you try it before dismissing it). Also like others have said, a really good subwoofer can make worlds of difference to you. another thing to consider is room treatments.

good avr with xt32, good subwoofer and a decently treated room will provide many many more positive sonic benefits over a power amp. power amps do have their place though.

Thanks J...

I apologize that this thing has gone off the proverbial rails yet again, so I'd like to thank you, duc and everyone else who has helped me through the fog and smoke of the uber-technical side effects the thread caused...let's try to refocus a bit and get back on track.

First, yes, right now, I am NOT experiencing any distortion, fatiguing or clipping even when pushing the 605 a bit in volume (and I have my Blu-ray player's input on the receiver, one of the HDMI jacks, tweaked via Onkyo's "IntelliVolume" system which is supposed to balance out the trim of each input device, but which I am using as a sort of "amp stage gain" control as seen on power amps of some years past that were adjustable for tweaking the "input gain" -- thus, for example on my setup, I'm running the "DVD" input of the 605, which receives audio and video signals via HDMI from my OPPO BDP-83, at "+10dB" on IntelliVolume, making the brute strength of the receiver "appear" louder at a somewhat lower volume level reading on the front panel).

I KNOW I need a better sub, secondly, and that is definitely on my upgrade to do list...

I'm DEFINITELY not running these RTi12s full range, instead crossing them over at 60Hz, so I should be alright in terms of easing up some load on the 605, correct? The center and surrounds are crossed at 80...now, given this, I should be giving the receiver some more headroom to work with, right? Essentially, I suppose what I want to know is if Polk's technical support gave me the right advice about all this with regard to the fact that the 605 CAN drive the 12s sufficiently being that they're crossed over at 60Hz...and that by doing this, it IS allowing my 12s to "dig a bit deeper" into their capabilities WHILE passing off all sub-bass to my sub (even though the PSW350 is far from a capable subwoofer)...

Now,getting back to power amps -- I see what Jeff is saying, I suppose, with regard to a good power amp really making the RTi12s open up and "sing" but the fact of the matter is, as we have all been discussing, I don't really CRANK the living hell out of this system and I'm not getting any kind of clipping issues at our current SPLs...so adding a power amp would just be for those moments I would want to "see what my system could muster" and to feel comfortable that the extra headroom WAS there. That being said, I agree that my first line of duty would be to replace the AVR with a more powerful one with preouts and go from there...

I think there's something to be said about the fact that I didn't choose more "difficult to drive" Polks like the LSi's with their lower impedance and sensitivity as compared to the RTis -- even though Jeff made it abundantly clear several times that I have an "aging and underpowered" AVR...do you agree? I mean, leaving the RTi12s crossed over at 60Hz, which allows a bit of the "full range" tendencies of these large towers to do their thing, plus running the receiver at five channel form, not seven, should yield more efficient, low distortion performance from the Onkyo, should it not?

Should I even consider one of these line level converters to utilize my 605 with an outboard power amp?
post #120 of 213
Quote:
Originally Posted by IntelliVolume View Post

Essentially, I suppose what I want to know is if Polk's technical support gave me the right advice about all this with regard to the fact that the 605 CAN drive the 12s sufficiently being that they're crossed over at 60Hz...and that by doing this, it IS allowing my 12s to "dig a bit deeper" into their capabilities WHILE passing off all sub-bass to my sub (even though the PSW350 is far from a capable subwoofer)...

Yes and no. They were correct in that your 605 can and IS driving your speakers sufficiently if you are not clipping it. It is not correct that crossing your speakers to a sub allows your speakers to dig deeper. On the contrary, it neuters your speakers below the crossover frequency by rolling off those frequencies from reaching the speakers at all.

Quote:
Originally Posted by IntelliVolume View Post

Now,getting back to power amps -- I see what Jeff is saying, I suppose, with regard to a good power amp really making the RTi12s open up and "sing" but the fact of the matter is, as we have all been discussing, I don't really CRANK the living hell out of this system and I'm not getting any kind of clipping issues at our current SPLs...so adding a power amp would just be for those moments I would want to "see what my system could muster" and to feel comfortable that the extra headroom WAS there. That being said, I agree that my first line of duty would be to replace the AVR with a more powerful one with preouts and go from there...

As I and others have stated many times already in this and countless other threads, a properly designed external amp will not make your speakers "sing", "open up", "lift a veil" or any other colorful descriptions anyone wants to use any more than what the amps in your receiver are doing now. If you want to "see what your system can muster" then turn up the volume. If it's too loud for your comfort and you're not hearing any distortion then you have the headroom you need. If it distorts before that then you are amp limited. If you turn up the volume and it no longer gets loud then you are speaker limited.

Quote:
Originally Posted by IntelliVolume View Post

Should I even consider one of these line level converters to utilize my 605 with an outboard power amp?

This is the part that bewilders me. You state that you understand all of our advice about an external amp not making an ounce of audible difference and agree with it, but yet you continue to ask questions about whether or not to modify your system to add an external amp and how to do it. Several of us have given you the numbers and science to explain the why and one person with anecdotal, subjective testimony comes in to contradict us and you forget about the science behind it.

You can choose to believe facts and science or the anecdotal testimony, but not both when they contradict each other. I understand what you're going through. I've been there and still go through it every time I make a purchase. At this point I don't think you will be completely happy unless you have an external amp powering your speakers regardless of the outcome.
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