Wich is the diference between... LSi and RTi

SamSagaZ

hey guys, i searched the forum and read the specs of both speakers and i really dont understand the diferences :S

for example RT10 go deeper than LSi15 and price is like half :S

LSi15 sound too much better than RT10? i mainly want to create an system to listen Music and for an 7.1HT.

i really want to purchase the better system that i can, i will wait more time and save money and purchase an good system that go with the money that i have right now and later dont be happy

The main problem is that here i cant listing the speakers because im in Argentina and in my city dont have any Store that Sell Polk Speakers and have some Samples Room.

4 Ohms impedance is not an problem for the receiver?

mmcgehee

Let me start by saying that the LSIs are very demanding speakers. Getting 250/watts at 4 ohms requires a pretty decent power amplifier. Also that the RTi's are exactly the best speaker for music. Not to say that they're bad, but you'll notice a lacking in the mid range.

That being said they're incredibly awesome. Personally I was going to buy an entire LSi's consisting of 15's for the front, 9's for the rears, C for the center, and an SVS Sub. After examining the cost however, even with my polk accommodation, was more than I could afford at the moment. Gonna have to wait for christmas.

Some things I found in my research. The LSi's are difficult speakers to drive, but once they're powered they're great speakers. I think the cheapest amp I found that could handle the req was about $1200. Used was going for around $800.

For the receivers you've been looking at, none will be able to properly handle it with the quality your seeking without an amplifier.

You should price out how much the RTi's complete system with amp is going to cost you vs the LSi complete system with amp. Then ask yourself if you can make step increases on your system or if you'd rather just wait and save.

SamSagaZ

ok, so looks like the best choice is to wait some time and purchase the LSi´s and an good amplifier.

looks like i need to start saving money.

sickicw

lsi are much better if you have the money, but rti are also very good if you are on a budget. Also, if you plan on getting the lsi, plan on spending lots of money on amps as well. They are pretty hard to get them to sound there best. My opinion is that the cheapest way to get them to sound near there potental is to buy two cheap or used 5 channel amps and bi amp all of your speakers. Also might want to look into installing one or two dedicated 20 amp lines for each amp.

Just so you get an idea of where i am comming from, I have both rti and lsi, and in order to get the lsi to sound nice and dynamic (for the budget i was am on), I had to use a 1000 watt car amplifier to run my left and right lsi9 speakers.

EDIT: if you don't bi amp your lsi speakers, you will need to worry about getting amp amp that is stable at 2 ohms, or else your lsi speakers will have lots of dynamic compression. In my expericance, amps that are only stable at 4 ohms sound too laid back. Then again, if you use a have a high crossover frequency, it might not make to much of a difference. Just make sure you give the amps enough juice to work properly.

SamSagaZ

sickicw wrote:

lsi are much better if you have the money, but rti are also very good if you are on a budget. Also, if you plan on getting the lsi, plan on spending lots of money on amps as well. They are pretty hard to get them to sound there best. My opinion is that the cheapest way to get them to sound near there potental is to buy two cheap or used 5 channel amps and bi amp all of your speakers. Also might want to look into installing one or two dedicated 20 amp lines for each amp.

Just so you get an idea of where i am comming from, I have both rti and lsi, and in order to get the lsi to sound nice and dynamic (for the budget i was am on), I had to use a 1000 watt car amplifier to run my left and right lsi9 speakers.

EDIT: if you don't bi amp your lsi speakers, you will need to worry about getting amp amp that is stable at 2 ohms, or else your lsi speakers will have lots of dynamic compression. In my expericance, amps that are only stable at 4 ohms sound too laid back.

Thanks dude, what abt Professional Amplifiers? i can get 300/Channel or 500/Channel amps from china, i talked with a few factories.

Maybe i can order it and test it, but really are scared i dont want to spend too much money in amps that put too much distortion on my speakers!




this is how one of these looks inside.

i can order 250, 500, 800 watts/channel.

you think that i need to goto some good brand to amp the speakers? or 1 watt of an good brand = 1 watts or any brand?

sickicw

well you mainly want to be concerned with high current, not somuch as how many watts...

what you should be looking for is something that can put out
x watts into 8 ohms and
2x watts into 4 ohms, and maybe even
4x watts into 2 ohms.

Something like
100 watts into 8 ohms and
200 watts into 4 ohms should be a pretty good amp.

Of course the THD rating should be pretty low too. like under 0.5 or 0.1

wingnut4772

I used to have a set of the LSIs and I was never fully satisfied with the sound until I purchased an Earthquake Amp which delivers a crazy 600 watts into 4 ohms. I do think that most people would be satisfied for the most part with something ike an Outlaw amp at 200 watts per channel but I don't think I could recommend anything less than that for a full HT set up with the LSis.

SamSagaZ

1.Total Harmonic Distortion: 20Hz～20KHz<0.1%
2.Frequency Response: 20Hz～20KHz±0.5dB
3.SNR: ≥100dB
4.Intermodulation Distortion: ＜0.1%
5.Input Impedance: 20KΩ
6.Input Level: 0dB
7.Operating Voltage: AC220V±5%　50Hz±2Hz

2 x 150W@8ohms
2 x 300W@4ohms

this i think that will match perfectly to the lsi15 series


btw the onkyo receiver TXSR803B is rated at 105Watts/Channel at 8 ohms!
so i think that will be ok for the LSi 15s. The onkyo is rated 180 W/Ch at 4ohms.

or i need 2 of these receivers and biamp the speakers!

F1nut

Pro amps, in general, are not noted for quality sound and those fans will get on your nerves.

SamSagaZ

well, so i can use one onkyo to biamp the fronts and center channels, and another to rear and surrond channels.

mmcgehee

You can but I'm willing to bet you kick it into protection mode. When we used to carry the LSi line in warehouse (now its special order) a co-worker sold a full LSi system to his brother with this Onkyo:

http://www.soundandvisionmag.com/article.asp?section_id=1&article_id=596&page_number=1&preview=

They sounded good, but it was pretty easy to send it into protection mode.

sickicw

just use the onkyo to power at most one set of rears. Use the amp described above to demo out the lsi15s. if it works good for you, then buy another for the center and then maybe another for the surround. If you end up going this rout, just remeber that you are way over the limits of at 15 amp circuit. you will need to invest in some dedicated power lines.

EDIT, also remember that setting up a good 5.1 theater is much cheaper than setting up a good 7.1 theater, and 5.1 sounds almost as good, unless you have a huge room.

LessisNevermore

F1nut wrote:

Pro amps, in general, are not noted for quality sound and those fans will get on your nerves.

Apologies to Sam for the interruption,

I have a question F1, no sarcasm or trouble intended.
Why is it that "audiophiles" (in general) painstakingly select components to exactly reproduce the sound of a live performance, when live performances (the preferred sound) are produced using these supposedly inferior amps and speakers. Modern pro audio gear is made to be reliable and clean. I would think that a studio grade amplifier and preamp would be every bit as clean and pristene as a high quality,mass produced amp.

what's your take on this?

LuSh

You're assuming the live performance is "plugged in". It boggles my mind how people can offer such advice on spec alone. I first used a NAD 320BEE intergrated amp years ago with my Polk Audio LSi9's. The NAD at the time was rated at 50wpc, and sounded much more dynamic then the SimAudio I used a couple years later. Think quality not quantity with these speakers. These speakers demand quality but aren't Dynaudio's or Totems in terms of power consumption. A person I spoke with from Polk Audio uses a MF 3.2 intergrated and had great results with an Ayre intergrated rated at less then 80WPC.

sickicw

like I said, it is current and not so much watts, that determines how well your amp will sound. more watts usually means a better power supply which will reduce the current compression (and thus dynamic compression) that is directly associated with limiting dynamic range of the speaker. if all other factors being the same, then then the only things more watts would give you would be more volume. In the real world however, more watts sometimes means better components such as the power supply which is why some people feel more power is always better.

F1nut

LessisNevermore wrote:

what's your take on this?

In general, pro gear seems a bit too analytical (sound signature) and the fans are noisy. While that may be good in the studio, it's not always desirable in the home.

SamSagaZ

ok, thanks....

btw, maybe 7.1 system is too much, you say that 5.1 will sound the same as an 7.1 in an small room?

my room is really small (20x13ft):S maybe i can save some buck purchaseing 5.1 instead 7.1 but i want to purchase the best as i can (with my budget) and save the money of more surround speakers and purchase an bigger amp for my lsi´s

aaharvel

Sam, chances are a 7.1 setup in a small room will sound inferior to a well thought-out 5.1 system.

If your seating position is against the wall, then forget about it. Go 5.1.
My room dimensions are about the same as yours, and I've tried both.

SamSagaZ

oh, ok!. so will save the bucks for the others speakers and will purchase the LSI+more power!
Thanks GUys!

cheddar

SamSagaZ wrote:

ok, thanks....

btw, maybe 7.1 system is too much, you say that 5.1 will sound the same as an 7.1 in an small room?

my room is really small (20x13ft):S maybe i can save some buck purchaseing 5.1 instead 7.1 but i want to purchase the best as i can (with my budget) and save the money of more surround speakers and purchase an bigger amp for my lsi´s

Also, there are very few dvds that actually offer discrete 6.1 tracks to even use the back two speakers. So the receiver is usually just mixing 5.1 surround information to send to the back speakers.