RTi12's

RVJII

Anyone had a chance to evaluate these yet? I am looking at going with these or the LSi15's. I am leaning toward these just because the LSi's sound pretty power hungry even for my Onkyo TX-NR901.

bigsexy1

I was at a local CC just the other day, and they still don't have anything yet but the new center channel speakers, and a set of bookshelves. I'm looking forward to the 12s. I plan on probably eventually trading my 150s in on a pair as soon as they are on sale for a halfway decent price. I'm also probably going to eventually trade my 2 pairs of 70s in for 2 pairs of the 8s, as well as the center and 2 pairs of fxs.


BTW, if the 12s are anything like the 150s, then they will require just as much power as a LSi15.

RVJII

I guess my follow-up question should be is my Onkyo alone going to be enough to take full advantage of either the RTi12's or the LSi15's?

Stats:

Power Output* (8 ohm, 20 Hz-20 kHz, FTC)
Front L/R 110 W/Ch
Center 110 W
Surround L/R 110 W/Ch
Surround Back 110 W/Ch (L/R)

Power Output* (6 ohm, 1 kHz, FTC)
Front L/R 145 W/Ch
Center 145 W
Surround L/R 145 W/Ch
Surround Back 145 W/Ch (L/R)

Dynamic Power** (front)
3 ohm 280 W/Ch
4 ohm 220 W/Ch
8 ohm 140 W/Ch

VR3

I heard the RTi12 on a 200 watt amp (great speaker btw), it needs a MONSTER amp to get bass. The 200 watt amp was on a dead leg at 90 some db, the RTi12 eats amps. Alot worse than the RTi150. It will most definetely eat your Onkyo alive. I am guessing 300-400 watts would do it for the i12. Possibly. Might need more, might just have been that 200 watt Conrad Johnson.

It might be able to drive the LSi, but not to its fullest abilities. Unless it has a killer amp section.

bigsexy1

RVJII
"I guess my follow-up question should be is my Onkyo alone going to be enough to take full advantage of either the RTi12's or the LSi15's?"

In a word, no.

Dr. Spec

I always think of it this way:

The typical decent powered subwoofer has a 300-500 watt amp for a single 12" high output woofer.

The RTi150 and RTi12 have at least that in woofer capability PER SIDE.

So you will need 300-500 watts per side for the bass drivers alone, much less the mids and tweets.

Also recall the RT3000p used 300 watts per channel, just for the powered woofer section (two 8" drivers).

300-500 watts per channel continuous into 4 ohms is not extreme at all for the RTi150 or RTi12 if you expect to drive them for bass heavy music or HT without a subwoofer.

bigsexy1

Hey Doc, believe it or not, the right channel of my Adcom 5400 amp went into thermal protection temporary shutdown yesterday, and it is powering the tweets/mids on my 150s! I got out the old manual, and if the temp goes above 85' C, then the thermal protection circuitry is activated. I was running them pretty hard with some old Van Halen and the volume set on about the 11:30 position (the distortion alert lights will just barely start to flicker on the 5400 with volume at the 12:00 position). For one thing, I do need to cut out some more and/or bigger holes in the back of my cabinet for air to flow for the Adcoms to breath (Mofset amps get hot anyway), but I'm starting to think that for the 150s/12s, I need to get one of those 300 watt Adcom amps, think the model # is 5802, or something like that, just to drive the woofers, and then move the 200 watt 5500 up to the tweets/mids, especially if I get the 12 with an extra midrange driver to boot.

Dr. Spec

Wow! Sending an Adcom into thermal protect is a feat to be reckoned with!

Yes, get yourself a few of those tiny computer cooling fans (Radio Shack) and mount them in the holes in the back of the unit, pulling air out (not blowing in).

Blowing air in tends to also blow in dust and dirt because the capture velocity of the fan blades is high enough to attract floating particles. Pulling air out (like a bathroom fan) creates a negative pressure inside the cabinet and it will still draw air into the cabinet, but not at a focused point like a fan. Infiltration in this manner has a low capture velocity and doesn't really suck in much dust/dirt at all.

That should improve circulation greatly and keep the Adcoms running cooler.

No arguments on your choice of amp upgrades - 300 watts to the woofs will work perfectly in a higher volume application. If anything, you've got more woof than the RT3000p ever had, and Polk used 300 with those.

bigsexy1

Doc, I had alrerady thought about the fans, but that is a very good idea, especially about letting them fan out instead of in to signifigantly cut back on dust.

You would think that the 5500 driving the woofers would be the first one to run into any "shutdown" issues, but it's the 5400 driving the tweets/mids. That's why I'm thinking that if and when I do get the 12s instead, and they have 2 mid drivers instead of 1, then that will only make it just that much worse on the 5400. I guess I'm going to start checking ebay, audiogon, etc. for the 300 watt Adcom amp, and after I get one, then move the 5500 200 watt amp up to the top end.

The 5500 is rated at only 75 watts more than the 5400, but I believe it's probably really a lot more than that. Plus, it has much bigger heat sinks, etc. It's really a much better amp than the 5400, even though it's the very next step up in the inventory line.

Emlyn

Big,
I haven't seen the RTi12s yet but am going to pay Circuit City a visit later today to see what they have now.

Concerning the RTi150s, I found I could run four of them with my RMB-1075 without the amp getting very warm. I also wasn't getting a lot of bass output though and the midrange was slightly compressed. When I switched to biamp just one pair, the power output from the amp seemed to increase dramatically and the amp does get quite warm to the touch when driven hard. I'm not sure why this is, but there may be much different current draw from the top and bottom ends of the speakers when they're set up in a biamp configuration. I don't have heat build up issues though because my Bell'O rack allows for lots of clearance all around.

I'd also guess the RTi12s will be even harder to drive than the RTi150s since they've added an extra midrange driver and the subwoofer drivers are slightly larger. Like Dr. Spec said in a previous post, the subwoofer sections of Polk's biggest speakers really should be treated like subwoofers and be driven by high current separate amps to get them working as they were designed.

Since I paid full price for my first pair of RTi150s, I'm thinking of trading them for two pair of RTi8s in cherry and using them for home theater set to small and driven just by my receiver. I am most likely also going to set up a separate two-channel only system elsewhere in the house with the newer RTi150s I got on closeout. They'll replace the RT55i paired with my PSW-450 I have set up now.

bigsexy1

"Since I paid full price for my first pair of RTi150s, I'm thinking of trading them for two pair of RTi8s in cherry and using them for home theater set to small and driven just by my receiver. I am most likely also going to set up a separate two-channel only system elsewhere in the house with the newer RTi150s I got on closeout."


Em, that's basically what I did. I traded the higher priced pair of 150s in for 2 pairs of the 70s just to be driven high passed by a 3803. It cost me about $300 extra for the 2 pairs of 70s for the 1 pair of 150s, but that was a lot cheaper than buying more amps.
I also got to keep a pair of 150s for a 2 channel set up, much like you are planning. Are you going to just bi-amp the 150s you will keep in the 2 channel set up with the rotel amp?

My Adcoms just run hot anyway. even when I was driving a highly efficient set of Klipsch Epic CF3s (102 db sensitivity) with them, they would still get hot.

Tour2ma

Originally posted by Emlyn
When I switched to biamp just one pair, the power output from the amp seemed to increase dramatically and the amp does get quite warm to the touch when driven hard. I'm not sure why this is, but there may be much different current draw from the top and bottom ends of the speakers when they're set up in a biamp configuration.

Along with bs1's experience a surprising result since the ohm rating should increase, and thus the current draw decrease, in a bi-amp configuration...

Possible that the load thse speakers present when driven really dips low...

EDIT: Dropping from 4 - 150's to 2 of them does require more of the mains to achieve the same SPL, but still have to think the bi-amping should be capable of this... More to ponder...