Polk RTI A9 Home Theatre setup - Power Amp Crown XLS 2002 vs Emotiva xpa-2

Hey everyone. I'm new here in the forum but I have been a Polk Audio owner for 3 years now. I have a pair of RTi A9's and I love those speakers. When I first bought them I was not too happy with their sound until I discovered that I just wasn't feeding them enough power. This speakers will sound 3x better when you power them correctly.

I'm passively bi-amping them. I'm using a hotrodded Dynaco ST 70 for the top section and a Crown XLS 1500 for the bottom. I have the Crown using the low pass filter, crossed over at 165hz. They sound very very good in my opinion.
The new Drive core Crown XLS amplifiers are great amps for the money. Highly recommend.

mkr252 wrote: »

@fastmatt:
Crown XLS 2002 has "Selectable input sensitivity; 1.4Vrms and .775Vrms options so that amp can be driven at full power".
My AVR Marantz 7009 has 1.4 vmrs. Question: Does it mean that my receiver can make the Crown XLS 2002 drive at full power??

Typically pro amps are 1.4 volts and the consumer stuff is 0.7 something. Most pro amps are set at 1.4 volts and to raise the level to work with consumer gear you have to use a CleanBox Pro. Some work ok without it, like Behringer iNuke. With the XLS you can just change the sensitivity with the press of a button. Problem with this is that the noise floor goes up. Ideally you'd have XLR's at pro levels going into the amp if possible so you can keep the lower sensitivity. But yes, it works fine with RCA cables, I used a 2502 as a sub amp and many many people use these for their highs.

mkr252 wrote: »

1) Do I need a Power amp in the first place??

in the room you described 15 X 25(?) YES!!

mkr252 wrote: »

2) If yes, what would you recommend between Crown XLS 2002 vs Emotiva xpa-2 to power the RTI A9s?

at the risk of a tomato or 2, I'll mention Rotel as merely another choice, but I'm going w/the flow on this one.

I have yet to get sufficient quality & quantity of time w/music, to properly evaluate SQ of my two 5 channel amps, neither of which have issues driving my LCR.

MetropolisLake wrote: »

mkr252 wrote: »

3) I was talking to a home theater specialist* at local store. He says, If it use a power amplifier to power front speakers, they are going to out power my center channel and I can't hear any dialogues from my center channel when I watch movies . Is that true??

Your boy* is an idiot. That's why you can change the gain and the levels. However, ideally you'd be running identical LCR's and run the same amp on all three.

+1! Further, whether you're running a 3 channel for the LCR or a 5 channel for 5.X, I find the LR needs about 5-6dB more than the CC, invalidating the "idiots*" argument. Don't take this as a reason to short change the CC's need for Quality power, however.

By the same token, as Metro mentioned, your listening tastes* MAY allow for modest power amp(s). As others have made clear I promise you: a robust (quality*) 85-100(+) can sound quite impressive powering all but the most inefficient or difficult loads.
*there's that word again. Or "it ain't just about the numbers, dude."

Cheers

gp4jesus wrote: »

Further, whether you're running a 3 channel for the LCR or a 5 channel for 5.X, I find the LR needs about 5-6dB more than the CC, invalidating the "idiots*" argument. Don't take this as a reason to short change the CC's need for Quality power, however.

You may prefer that for some reason, or your distances and heights may dictate this, but with identical LCR’s, when something pans across the screen, it’s not supposed to start on one side at the right level, dip 6 db in the middle, then fire back up on the other side. It’s supposed to be identical and seamless, that's the entire point. I've never heard of anybody killing their center that much, if anything they boost it a little. Assuming everybody needs a 6 db cut just isn't reality.

MetropolisLake wrote: »

... but with identical LCR’s,

I don't understand what you mean by this phrase. Check my sig.

MetropolisLake wrote: »

...when something pans across the screen, it’s not supposed to start on one side at the right level, dip 6 db in the middle, then fire back up on the other side. It’s supposed to be identical and seamless, that's the entire point. I've never heard of anybody killing their center that much, if anything they boost* it a little.

I don't know*, but my ears & the spl meter seem to agree even after my third upgrade the latest a different brand prepro from the previous 2. During viewing I occasionally notch it up or down slightly...

MetropolisLake wrote: »

Assuming everybody needs a 6 db cut just isn't reality.

something for a survey, perhaps.

gp4jesus wrote: »

JCsound wrote: »

I have been contemplating removing the original crossovers but haven't got the courage to do that yet.

Go for it, dude! At least so just your EXO controls things between the bass & mids. Expect a little more output & control in the lowest 3 octaves, if you follow my in my foot steps.

I did just a few months after I got my 'A7s. Further, I modded one. Listened for differences between it & the other. Then did the same to the other & haven't looked back! Mods include:
removed LP filter to the bass drivers & upgraded wire for same to 8 gage
upgraded wire to 12 gage** between mid/tweet BP & XO;
same** between XO & mid
glued damping to speaker baskets & magnets.

Did similar stuff to my CC & surround speakers too. Time invested, not wasted.

Note: for whatever reason the 'A7 mid does not have a HP filter, IMHO a "problem" that bi amping corrects. Further the mid & bass drivers share the same closure volume, another problem I plan to correct soon.

No flame outs (over the wire upgrades) from the peanut gallery please!

Accept my apologies for thread hijack. Tony

I have just finished doing a few mods to them just last week. Little by little I have turned my A9's into what I believe is a better speaker than what came out of the factory.

The first mod I did was to apply dampening foam material inside the whole cabinet and the separate enclosure where the mids and tweeter are. That tighten things up, I consider that a must have mod.

The next mod I did was modifying the crossovers. I left all the capacitor and resistors values the same but upgraded to better made components. I used soniccap capacitors and mills resistors, those mods made the speakers sound a bit cleaner and the bass a bit punchier.

The next mod I did, was remove the metallic wood screws that hold the speaker in place. I used brass inserts and non metallic screws, that allows me to remove the drivers as many times as I need to and not worry about the wood in the cabinet holding the screws getting weaker. Also it allows me to increase the torque on the screws which I torqued to 8in lbs.

Now this next mod was the one that made the biggest difference, I removed the original tweeter and installed a vifa dual ring radiator tweeter just like the one used in the LSiM models. That took the speakers another couple of notches up. It was a point of no return mod.

And lastly I removed the original cheap plastic feet and installed outriggers and spikes. That not only gave the speakers better stability and looks but also somehow a bit of cleaner bass.

It was been quite interesting seeing what all this mods do to the speakers.

I might take your advise and remove the LF section of the crossover and see how that sounds. It might be a while tho, since my fiance is starting to get a bit jealous about how much time I'm spending tweaking my sound system.

JCsound wrote: »

gp4jesus wrote: »

JCsound wrote: »

I have been contemplating removing the original crossovers but haven't got the courage to do that yet.

Go for it, dude! At least so just your EXO controls things between the bass & mids. Expect a little more output & control in the lowest 3 octaves, if you follow my in my foot steps.

I did just a few months after I got my 'A7s. Further, I modded one. Listened for differences between it & the other. Then did the same to the other & haven't looked back! Mods include:
removed LP filter to the bass drivers & upgraded wire for same to 8 gage
upgraded wire to 12 gage** between mid/tweet BP & XO;
same** between XO & mid
glued damping to speaker baskets & magnets.

Did similar stuff to my CC & surround speakers too. Time invested, not wasted.

Note: for whatever reason the 'A7 mid does not have a HP filter, IMHO a "problem" that bi amping corrects. Further the mid & bass drivers share the same closure volume, another problem I plan to correct soon.

No flame outs (over the wire upgrades) from the peanut gallery please!

Accept my apologies for thread hijack. Tony

I have just finished doing a few mods to them just last week. Little by little I have turned my A9's into what I believe is a better speaker than what came out of the factory.

The first mod I did was to apply dampening foam material inside the whole cabinet and the separate enclosure where the mids and tweeter are. That tighten things up, I consider that a must have mod.

The next mod I did was modifying the crossovers. I left all the capacitor and resistors values the same but upgraded to better made components. I used soniccap capacitors and mills resistors, those mods made the speakers sound a bit cleaner and the bass a bit punchier.

The next mod I did, was remove the metallic wood screws that hold the speaker in place. I used brass inserts and non metallic screws, that allows me to remove the drivers as many times as I need to and not worry about the wood in the cabinet holding the screws getting weaker. Also it allows me to increase the torque on the screws which I torqued to 8in lbs.

Now this next mod was the one that made the biggest difference, I removed the original tweeter and installed a vifa dual ring radiator tweeter just like the one used in the LSiM models. That took the speakers another couple of notches up. It was a point of no return mod.

And lastly I removed the original cheap plastic feet and installed outriggers and spikes. That not only gave the speakers better stability and looks but also somehow a bit of cleaner bass.

It was been quite interesting seeing what all this mods do to the speakers.

I might take your advise and remove the LF section of the crossover and see how that sounds. It might be a while tho, since my fiance is starting to get a bit jealous about how much time I'm spending tweaking my sound system.

pics please, and lots of them.

Here is a link to a video I made. It doesn't sound the same as when they are heard in person but the main sound is there.

https://youtu.be/_jOea-9BJ_A

JCsound wrote: »

Here is a link to a video I made. It doesn't sound the same as when they are heard in person but the main sound is there.

https://youtu.be/_jOea-9BJ_A

AMAZING!!!!!! Sounds just like my Dell desk top speakers

Great work man!!! I'd love to be able to hear those in person, VERY intrigued to hear what a dif the tweeters alone made.

Nice work on the spikes, thanks for the inspiration!

F1nut wrote: »

JCsound wrote: »

All I can say about the tweeter mod is, that the speakers sounds more musical now. The highs are not as edgy, they are smoother and a bit more refined. Also this tweeter plays up to 40khz. In my own opinion is a well worth it mod. PM me and I'll send you the tweeter info.

Since the parameters of the RTiA9 tweeter are unknown and you didn't change the values on the crossover the odds of that ring tweeter matching the original specs have to be a million to one.

You are right, I didn't know the parameters of the original A9's tweeter. Those can be found using test equipment "which I don't have" But what I do know is that, it is crossed over at 1800 Hz, plays up to 23khz, and that it is a 4 ohm , 1" tweeter. so, with that in mind I set out to find a tweeter that matched or beat that. I knew that any tweeter I would find would be a gamble to install in the A9's. There were 3 possibilities 1. It would sound horrible, 2. It would sound the same "very unlikely to happen", 3. Sound better that the stock one.

So, I decided that one that doesn't take a risk won't win anything. With that in mind I found the radiator tweeter, I looked over all of its specs, saw a performance charts and proceded to take a semi-educated gamble. I knew that if the tweeters didn't work I could save them and use them down the road for something else.
So I ordered them. When I received them, I proceeded to remove the original tweeter and build a temporary rig to hold the new tweeter in. I then listen to the speakers for a while before fully committing to implement the change.

They sounded better to me that the stock ones, so I moved on to fully gut the original tweeter from its housing and permanently implement the change. I haven't looked back since, it was worth the gamble. Even tho I'm not sure of how things will read now if one was to take measuraments, I know ultimately the important test is how they sound, it doesn't matter how good they test if they sound bad. On the other hand you may have drivers that don't test very well but that will surprise you when you actually listen to them.

It was very interesting mod, and I have always been curious to see how far this speakers can be taken.

Jc

JC, thank you for that and you're right, it's about how things sound. If I may suggest, you need to try some different speaker cable. Anyway......

This is a mod I did on my RTiA7/CSiA6/FXiA6's for much the same reason, the tweeter was too hot. I felt the mod addressed that issue quite nicely. I also replaced the stock driver screws with stainless steel cap screws going into Hurricane nuts. I thought about using brass inserts as it would have been much simplier, but brass strips too easily. For the RTiA7's and Sanus UF30 stands I had custom stainless steel spikes made.

http://forum.polkaudio.com/discussion/159998/rtia7-and-csia6-crossover-upgrades-a-slightly-different-approach/p1

To view the photos, click on the shaded gray boxes at the bottom of the pages.

Well, not quite JC. You retained some of the stock caps and used some Daytons along with one Sonicap. I used all Sonicap.

F1nut, I'm actually using 2 sonicaps per crossover. I used the Dayton for the low end section.

gp4jesus, I agree with you. I think Polk also agrees with that, that is why they used different tweeters for their flagship line. I think the tweeters in the Rti line are more directed towards the home theater sound, while the dual ring is targeted towards their musical crowd.

JC: "...to fully gut* the original tweeter from its housing and permanently implement the change. "
How tough was that*? I have my eye on several replacements (Vifa & TB) that graph flat & smooth. Further I think won't require many brain cells to install. OTOH you've proven success...

Also where did you buy those Outriggers? I want to fit them to my 'A7s.

And...I used an inexpensive foam material (for damping) that comes in 2" wide 25' or 50' rolls. I'll get back to y'all the brand. I'm certain Dynamat does it a bit betta' but fo' mo' $.

Finally, I upgraded any and all wire inside* that carries midrange w/AR 12 gage; bass drivers w/8 gage. I did not upgrade any wire between XOs & tweeters - I think its adequate (oops?) I immediately noticed fuller male voices (CC) and tighter, "thumpier" drums, etc (LCR)
* all speakers

Sub internal wiring still stock, but I've been VERY busy lately.

Tony