so if i was to get an amp

[bryantm3]

for my two polk audio (maybe four within a couple of years) RTi8s (i was going to go ahead and get a 200W/channel ampifier, i don't want to bother wih anything lower. currently i'm giving it 100W/channel, but it may be lower.) and i was looking at options. the recommended power for the RTi8s is 20-250 watts. i cannot find monoblock or multiple channel amplifiers above 200W, but 200W should be enough, shouldn't it? my 100W setup is giving me a decent midrange, but pretty weak highs + lows. it's not how loud they can get. they can get pretty loud, just they don't get very good highs and lows. so will upgrading to 200W make that much difference, or do i need to go all the way to 250?

option 1 is getting four monoblock 200W amplifiers, so i'm guaranteed to have 200W going to the speakers at all times.

pros: cheaper, and since speakers 3+4 will be on opposite sides of the room from 1+2, i won't have to run speaker wire (ie: bare wire, banana plugs, spades) over 20 feet, i can just run insulated wire.

cons: i'm running out of power outlets; i've got surge protectors plugged into surge protectors already.


option 2 is getting a 5 channel 200W/channel amplifier.

pros: gives me more space. less things to plug in, and less of a fire hazard. also will give me the ability to add a centre channel at some time or another.

cons: i will have to have at least two banana wires or spades or something running under the floor for 20 feet. i'm pretty sure a lot of power could be lost by that. also i'm not guaranteed to get 200W/ a channel with a combination amp like that; i'd probably only get 175 a channel.

these were the ones i was thinking about:

monoblock:
http://outlawaudio.com/products/2200.html

5 channel:
http://outlawaudio.com/products/7500.html


and currently i've only got two speakers. the quatrophonic setup will be in the future.

 

[Doug917]

Ask anyone who has onwed both the monoblocks and the mulit-channel amps from Outlaw and you will hear that the multi-channel amps will take anything you throw at them, while the monoblocks are not as strong (ask TDeluce on this one).

If you do go with a multi-channel amp, just make sure you use 12Ga speaker wire and the loss of power will be minimal.

Figure out if balanced inputs are important to you or not. If not, the older model 2000 (monoblock) and 755 (5-channel) could save you some serious dough buying used. Outlaw transfers the warranty on all their merchandise so you are protected for some time by buying used.

 

[jcPanny]

Emotiva MPS-1

Check out the 7 channel Emotiva MPS-1 from av123.com for $100 more ($1700) than the outlaw amp. It is a monoblock design with 200 @ 8 and 300 Watts @ 4 ohms. Use the extra amp channels for the center, zone 2, etc. It is also a fully balanced design, unlike the outlaw.

PS. the Emotiva UL amp for $600 will also deliver 200 Watts into 4 ohms. x 6 channels.

 

[tomd51]

From a convenience standpoint, the multichannel amp is a better solution, IMO. I wouldn't concern yourself that the Outlaw wouldn't provide you with a full 200w per channel all channels driven simultaneously. I've got the older Outlaw 755 200Wx5 and this thing's a beast.

You won't lose any power w/a 20ft. run, but as Doug suggested, make sure you're using 12AWG wire for the run. You could likely even get away w/14AWG, but the price difference is minimal for a 25ft. run.

One last suggestion would be to consider a used amp from Audiogon. Amps are pretty much bullet-proof and will last a long time if properly cared for. You could save yourself anywhere from $500-800 on going this route, just a consideration... -TD

 

[bryantm3]

really? wow, this has changed my mind- i had about decided to go with 2 monoblocks for now and later buy another 2. should i really spend 300 more dollars on a multichannel amp? (i'm probably not going to buy one used... i don't buy electronics used. maybe i'm foolish, but i only buy used records, cds, books, etc. i just want to be able to have a warrenty; what if i get it home and it blows up in a week?

 

[bryantm3]

From a convenience standpoint, the multichannel amp is a better solution, IMO. I wouldn't concern yourself that the Outlaw wouldn't provide you with a full 200w per channel all channels driven simultaneously. I've got the older Outlaw 755 200Wx5 and this thing's a beast.

You won't lose any power w/a 20ft. run, but as Doug suggested, make sure you're using 12AWG wire for the run. You could likely even get away w/14AWG, but the price difference is minimal for a 25ft. run.

One last suggestion would be to consider a used amp from Audiogon. Amps are pretty much bullet-proof and will last a long time if properly cared for. You could save yourself anywhere from $500-800 on going this route, just a consideration... -TD

also, where do i get a 12 gauge wire? i'm not sure that they have these at the local hi-fi store.

plus, what kind of cables do you use to go from the pre-outs to the amplifier? just RCA cables, right?

 

[Reorx]

What is your price range for the amp(s)?
Where you trying to keep it around $1700 or can you spend a little more?

Personally, I'm going to be buying a Earthquake Cinénova Grande 7-Channel next month. I've heard nothing but good about them, and they have great reviews. The 5-channel amp is selling for $2300 on ebay.
http://www.earthquakesound.com/cng_5.htm

12 gauge wire you can buy online.
http://www.bluejeanscable.com/store/speaker/index.htm
or impact acustics. You can go cheaper using ebay.

 

[tomd51]

Several people buy amps from previous owners via Audiogon and elsewhere every day. If the amp craps out after a week or two and the previous owner is a reputable seller, they likely will work with you to either give you a refund or get it fixed. The lack of a warranty is definitely a consideration, but as I mentioned, most amps are pretty sturdy and well built. There's nowhere near as many possible issues one may encounter with an amp as they might with an A/V receiver. The cost savings is also one reason a used unit may be more attractive to some, but it comes w/some risk.

You can find 12AWG cable at most home improvement/hardware stores (Home Depot, Lowes, etc.) and have them cut a pre-determined length of wire for you. If ordering online is possible for you, take a look at Monoprice for some good pricing on some speaker cable.

A good set of RCA cables (nothing exotic needed) from the pre/pro to the amp typically will work just fine, you can also find some of these at Monoprice. If you've got your pre/pro in a different location than the amp and it's a fairly substantial cable run (more than 10ft), you may want to consider XLR cables (balanced) as opposed to the RCAs, assuming the amp has these for connection options. They'll both sound the same, but the XLR connections allow you to avoid any RF interference which may be more common w/longer pre/pro <-> amp runs... -TD

 

[Doug917]

bryantm3,

You can't lose buying an Outlaw used amp. The one I have that I mentioned I have for sale in my PM to you still has almost 4.5 years of warranty left on it. This means you get an amp that works and looks like new for much less than new, but still have coverage against the unit crapping out on you for a long time. If you don't need the balanced inputs that the new 7500 provides, the 755 or any other used Outlaw unit with warranty left is a great deal.

 

[tomd51]

Good point, Doug, forgot about the transferrable warranty that many amps (including Outlaw) have available... -TD

 

[NGL_BrSH]

i think before i went and spent a lot of money on a new amp i'd go demo my speakers on a larger amp at a store. I'd guesstimate that about 85% of the sound make up or more is from the speakers. If at low levels of volume you're still not getting a satisfactory sound, i'd say the speakers are not to your liking.

 

[tomd51]

After re-reading your initial post, bryantm3, I think NGL_BrSH is right. It sounds more as though you're not satisfied with the sonic characteristics of your RTi8s as opposed to not having enough power. You haven't mentioned what you're currently powering them with, but if its a decent mid-level receiver, it's likely providing enough power.

You may want to consider looking into different mains as opposed to adding an amp, the amp will only provide a louder and possibly more open and cleaner signal, it won't change the speaker characteristics. While it may help on providing an output increase on the lows, the highs will likely remain unaffected. Maybe less distortion or better clarity at high volume levels, but the high frequencies will likely remain the same, just louder.

Probably not exactly what you wanted to hear, but keep it in mind... -TD

 

[bryantm3]

After re-reading your initial post, bryantm3, I think NGL_BrSH is right. It sounds more as though you're not satisfied with the sonic characteristics of your RTi8s as opposed to not having enough power. You haven't mentioned what you're currently powering them with, but if its a decent mid-level receiver, it's likely providing enough power.

You may want to consider looking into different mains as opposed to adding an amp, the amp will only provide a louder and possibly more open and cleaner signal, it won't change the speaker characteristics. While it may help on providing an output increase on the lows, the highs will likely remain unaffected. Maybe less distortion or better clarity at high volume levels, but the high frequencies will likely remain the same, just louder.

Probably not exactly what you wanted to hear, but keep it in mind... -TD

i'm running it on a reciever that promises 100W/channel, but since i've got more than one speaker, it's probably less- maybe around 90 or 75 watts per channel. i don't really think that's enough, considering the max is 250 watts per channel. also i've had a couple of threads here discussing this- i'm getting decent midrange, but the low and high frequencies seem to be weaker. and when i turn the volume up, the bass sounds slightly distorted.

 

[nibhaz]

bryantu3,

The advice you've received from the last two posters, is the best so far. Your largest ROI comes from the speakers, so if you don't like the sound, you should really be looking at a new set of speakers rather than more power.

With that said, there are some speakers out there that present a difficult load for the amplifier to drive, so in these cases there can be some sonic improvements by investing in more power. From what I've read, the RTi8's impedance actually measure closer to 4ohms rather than the published 8ohms, so if you are doing a lot of listening at high volumes, then perhaps your receiver is having hard time driving the RTi8s. Thus, more power may actually be a solution for your situation.

Are you using a sub? If you are, then power is not likely your problem, since you are removing the strain of producing the most demanding frequency from your receivers’ amplifier section. If you’re not using a sub, then perhaps this is another avenue of approach to your situation.

 

[tomd51]

To build on nibhaz's post, even if you're using a sub but running the RTi8s full range, this may be a bit of a strain on the receiver itself as low frequencies tend to allocate more power.

If you're running the RTi8s as 'small' w/a crossover set to 80Hz or higher, the sub should be handling anything under 80Hz and as such, the sub could be the root of the weak sounding bass, however I don't believe this would have any bearing on your lack of high frequencies.

How are your speakers configured in regards to your receiver and if you are using a subwoofer, what is the crossover level you're using? -TD

 

[bryantm3]

when i speak of bass, i'm talking about bass above 120 Hz and below about 1 Khz. i am running a subwoofer, but it's not too great- it's a PSW10 or something like that and i've got the crossover at 80Hz. sometimes i put it at 120 Hz because it actually tends to sound better coming from my RTi8s.


about the impedance rating- what does all of this mean- does 4 ohm mean it's harder or easier to power? and these amps i'm looking at say 200 watts @ 8 ohms but 300 @ 4. does this mean my speakers will blow up if i hook them up to this??

 

[Swerd]

i'm running it on a reciever that promises 100W/channel, but since i've got more than one speaker, it's probably less- maybe around 90 or 75 watts per channel. i don't really think that's enough, considering the max is 250 watts per channel. also i've had a couple of threads here discussing this- i'm getting decent midrange, but the low and high frequencies seem to be weaker. and when i turn the volume up, the bass sounds slightly distorted.

If you're receiver promises 100 watts/channel it will make little difference whether they are plus or minus 10 or even 25 watts. It's even questionable whether doubling the power to 200 watts will make a significant difference. To make more than a just noticeable difference you need to boost the power by 3- to 10-fold. It is more likely that you could hear improved sound with different speakers than with an amp that is twice the power.

Also, when most speaker manufacturers cite a maximum power, they don't mean that you really need 250 watts, they mean don't go higher than that value or you may exceed the thermal capacity of the speaker's voice coil.

 

[jcPanny]

Speaker impedance

Your speakers are listed as 8 ohms, which is pretty standard and should be compatable with any amp or receiver. Some speakers are in the 4-6 ohm impedance range, which requires the amp to deliver more power to the speakers. 4 ohm speakers in particular require a good mid-fi receiver or an outboard amp to drive them.

To test the performance of your Polks on your current system, run them in stereo mode. Your receiver will be much closer to its rated power than when running a 5-7 channel HT. Also, as you lower the crossover frequency (on the receiver) and send more bass to the Mains, you increase the power requirements of the receiver or amp.

 

[nibhaz]

This hobby is complex!

when i speak of bass, i'm talking about bass above 120 Hz and below about 1 Khz. i am running a subwoofer, but it's not too great- it's a PSW10 or something like that and i've got the crossover at 80Hz. sometimes i put it at 120 Hz because it actually tends to sound better coming from my RTi8s.


about the impedance rating- what does all of this mean- does 4 ohm mean it's harder or easier to power? and these amps i'm looking at say 200 watts @ 8 ohms but 300 @ 4. does this mean my speakers will blow up if i hook them up to this??

First off, if you raise the crossover point to 120 Hz, you are actually asking your sub to produce the bass up to 120 Hz, not the RTi8s. So if it sounds better to you with the sub producing this range of bass as opposed to the RTi8s then perhaps should be taking a harder look at the replacing your speakers rather than adding more power.

Now, in regards to the impedance, Polk claims that the nominal impedance of your speaker is 8 ohm. This means that they claim that the average impendence across the audio range is about 8ohms. (Note: impedance in a speaker system changes in relation to the frequency) However, some owners claim to have a measured a nominal impedance of about for 4ohms. This means that they require more current than an 8ohm speaker to reach the same spl. This can be a difficult task for some low to mid-end receivers to do at high spls, so depending on your set up and the spls you are listening at you may be stressing your receiver’s amplifier section and thus would benefit from having a more robust external amplifier. And no, you would not blow your speakers if hooked them up a amplifier that claims 300w into 4ohms.

However since you are using a sub and actually prefer the sound of your sub handling the upper part of the bass frequencies, I would take harder look at replacing the RTi8s. It sounds as if you are experiencing many of the opinions I’ve read about RTi 8s, and that is a lack of bass and treble with a bloated midrange. But these are merely others opinions and you need to make judgment calls with your own ears. IMHO the RTi8s are a good speaker at there price point, and from my own personal experience with them suggest they love power.

The questions really comes down to whether or not you want take the chance and buy an external amp, which may or may not help in your situation, or just take the money you were going to spend on amp, and buy a new set of speakers that you know will work in your current system after doing some listening test at home.

Another factor, which hasn’t been mentioned thus far, is the acoustics in your listen area. There may be some nulls in your listening position which wouldn’t be fixed by bigger amps or a different set of speakers (for the most part) in the same positions. So perhaps you should do some in room measurements before you make a decision to purchase more gear. The money may be better sent on some absorption and diffusion.

 

[Doug917]

I will agree acoustic treatment is the biggest diference I have ever made to my HT room. For the price of a good amp or a mid level receiver, great things can be done with acoustic panels if your room is problematic.

Not familiar with the Polk speakers you have. If they have at least 5.25" drivers, I would lower your crossover to 80Hz. The location of bass gets too detectable above 100Hz. The higher you set your crossover, the less you are having your Polks do.