Denon 3808 and Lsi

deepblue

I have Denon 3808 and am looking for the matching speakers. I found Polk Lsi15, 9 and center to be very good in both quality and discount. The only problem is that they run at 4 Ohm and there is the recommendation from Polk forum that 3808 cannot efficiently drive them. So, what's the solution?

- Still match these, but bi-amp them from unused surround to front.
- Find one 2 or 3 channel power amp with 200 watt per channel at 4 ohm, and let 3808 drive the other channels.
- Find 5 or 7 channel power amp with 200 watt per channnel at 4 ohm and use it alone.

I have done the research heavily but cannot find the one with the exact answer, and believe that this thread can help, please.;)

McLoki

You have answered your own question in reverse order of preference.....

5 or 7 channel amp is the best solution.

3 channel amp is lower cost and not quite as good a solution as above, but will probably work.

If you do not want an external amp at all, don't get one (and bi-amp if possible) but you will still be limited to lower volumes, keeping your AVR VERY well ventilated (it will run pretty hot), and potentially running your AVR into protect mode (not cool half way through a demo) or blowing your speakers (not cool anytime).

Good luck - The LSi's can be a pain to run properly, but are very much worth the effort.

Michael

cfrizz

Find 5 or 7 channel power amp with 200 watt per channnel at 8 ohm and use it alone.

Welcome to Club Polk DeepBlue.

deepblue

Thanks all for the warm welcome. I'll bring my Denon for test with Lsi and find out how loud or stable it can run? Agree with you that the best permanent way is to have single power amp to take care all 5 channels eventhough it's hard to find the right choice here (in Thailand). BTW, the shop try to offer me the obsolete Subwoofer, PSW1200. Actually, for a pair of Lsi15 and 9, and one center, together with PSW1200, they offer me $2,800 which is quite good compared with other brands in the same range like NHT or Monitor Audio at almost double the price. What do you think?:rolleyes:

cathpah

deepblue wrote: »

Thanks all for the warm welcome. I'll bring my Denon for test with Lsi and find out how loud or stable it can run? Agree with you that the best permanent way is to have single power amp to take care all 5 channels eventhough it's hard to find the right choice here (in Thailand). BTW, the shop try to offer me the obsolete Subwoofer, PSW1200. Actually, for a pair of Lsi15 and 9, and one center, together with PSW1200, they offer me $2,800 which is quite good compared with other brands in the same range like NHT or Monitor Audio at almost double the price. What do you think?:rolleyes:

Have you had a chance to test that speaker setup with the denon 3808? I'm thinking about purchasing this same receiver and speaker setup but I'm worried about the 4 ohm rating as well. Can you let me know how loud and stable you found that combo to be?

thanks

cathpah

cathpah wrote: »

Have you had a chance to test that speaker setup with the denon 3808? I'm thinking about purchasing this same receiver and speaker setup but I'm worried about the 4 ohm rating as well. Can you let me know how loud and stable you found that combo to be?

thanks

I guess I'll answer my own question. I went ahead and ordered everything and crossed my fingers....turns out it works perfectly. I've gone very loud for long periods of time with no issues whatsoever.

leroyjr1

You still should look into a nice 5 channnel amp. I will put a on your face.

cathpah

leroyjr1 wrote: »

You still should look into a nice 5 channnel amp. I will put a on your face.

I'm sure, but money is tight right now, and I'm running it as a 7.1 system so that would be pretty expensive.

mantis

deepblue wrote: »

Thanks all for the warm welcome. I'll bring my Denon for test with Lsi and find out how loud or stable it can run? Agree with you that the best permanent way is to have single power amp to take care all 5 channels eventhough it's hard to find the right choice here (in Thailand). BTW, the shop try to offer me the obsolete Subwoofer, PSW1200. Actually, for a pair of Lsi15 and 9, and one center, together with PSW1200, they offer me $2,800 which is quite good compared with other brands in the same range like NHT or Monitor Audio at almost double the price. What do you think?:rolleyes:

The Denon is not designed to handle a 4 ohm load. It's stable to 6 ohms. But it will drive the speakers just with barely no dynaic range. What happens is the amp has to use all of it's power to hold the heavier ohm load. Most receivers use smaller power supplies and caps. This is why most receivers don't do well driving lower ohm load speakers.

Buying amp will be nessary if you want to use that receiver and speaker combo. I suggest checking out the rt line, they are pretty fantastic and will run without adding any amps on your Denon receiver.

Good luck,

Dan

cathpah

cfrizz wrote: »

Find 5 or 7 channel power amp with 200 watt per channnel at 8 ohm and use it alone.

Is this really true? does the fact that that amp would have 200 watts per channel overcome the fact it's an 8ohm receiver? When I do buy an amp, I'll probably buy one used on audiogon, so a return policy isn't really an option there.

would i really notice a huge difference from a more powerful amp that is still rated to only 8 ohms? sorry if this is a noobish question...I still (and always will) have loads to learn.

Face

I would disregard the 200 watts at 8 ohms comment.

What it boils down to is, you need a high current amp capable of driving those speakers correctly. There's plenty of good choices out there such as Rotel, Adcom, Sunfire, B&K, etc...

cathpah

Face wrote: »

I would disregard the 200 watts at 8 ohms comment.

What it boils down to is, you need a high current amp capable of driving those speakers correctly. There's plenty of good choices out there such as Rotel, Adcom, Sunfire, B&K, etc...

sorry, when you say disregard it....do you mean it is false? Do i need to look specifically for an amp rated @ 4 ohms?

with very little research, I was looking at the outlaw 7700.

any solid/obvious recommendations for my best/cheapest option for this? I don't plan on doing much more upgrading for a while (had to convince the wife that these speakers would be all i'd need for the next 30 years...)

Face

It's not false, just a little confusing as you should be looking for something with 4 ohm ratings.

That outlaw will definitely get the job done.

tcrossma

I good quality high-current amp rated at 200w @ 8ohm will usually deliver somewhere between 300-350w @ 4ohm.

cathpah

Face wrote: »

It's not false, just a little confusing as you should be looking for something with 4 ohm ratings.

That outlaw will definitely get the job done.

great...thanks very much. Sorry for any thread hijacking that I may have caused.

That said, I should point out that I really haven't notice any faults in my setup thusfar....but I have no doubt that my system could sound even better with a dedicated amp. So, again, I want to say that the 3808 DOES work and I haven't had it go into safety mode a single time even while playing games/music/movies pretty damn loud. I just think that virtually every AVR could benefit from a dedicated amp, and thus that's why I've asked about amps.

MikeC78

It will work as you are experiencing, however; you'll be taxing that AVR making it very hot and losing out on dynamics/SQ. An external amp such as the Outlaw you are looking it will relief you of any problems and bring a grin to your face.

cathpah

MikeC78 wrote: »

It will work as you are experiencing, however; you'll be taxing that AVR making it very hot and losing out on dynamics/SQ. An external amp such as the Outlaw you are looking it will relief you of any problems and bring a grin to your face.

I believe you 100%, and wasn't saying that my setup is perfect at all.

I was just trying to answer the OP's question (will this setup work) and indeed it will.

now I personally, want to get an amp for the exact reason you stated...but that's different than what the OP asked.

MikeC78

Disregard then, for some reason I thought you were the OP.

cfrizz

Basically the more power the amp puts out at 8ohms the more power it will put out at 4. The more power you give to the LSI's the better they will perform! Hence the 200wpc recommendation.

But it's your money & your speakers so do what you want.

cathpah

cfrizz wrote: »

Basically the more power the amp puts out at 8ohms the more power it will put out at 4. The more power you give to the LSI's the better they will perform! Hence the 200wpc recommendation.

But it's your money & your speakers so do what you want.

ok...then I guess I am a bit confused. If my current avr can put out 140 wpc @ 8 ohms, then why do i need another amp? or am i mistaken on those stats?

cheddar

What you want is an amp that has control and room to spare over the watts it delivers to your speakers. 1 lousy uncontrolled watt from an overtaxed amplifier section can kill an expensive lsi speaker no matter what the stated rating is. People are merely telling you that large and in charge is better than overtaxed and huffing to deliver the watts. The truth is that speakers rarely see 100 watts anyways. At very loud listening levels, you may be putting 10 watts into your speaker.

Edit: Also, it's actually safer to exceed the power ratings of the speaker if you have controlled, clean power from a quality amp than it is to have that 1 lousy uncontrolled watt get through an underpowered receiver and smoke your speaks. Like I said, it's usually hard to go outside the power ratings of an lsi speaker anyways. But that's how important it is to have an amplifier that isn't being pushed to its limits...and of course they sound better too .

Ricardo

Receivers (with few exceptions) are not made to support 4 ohm speakers; they might have 140 or 200 WPC @ 8 ohms, but this does not mean they will be stable at 4 ohms.

Most if not all separate amps will support 4 ohm, and sometimes 2 ohm speakers.

tcrossma

cathpah wrote: »

ok...then I guess I am a bit confused. If my current avr can put out 140 wpc @ 8 ohms, then why do i need another amp? or am i mistaken on those stats?

Because most receivers don't live up to their power ratings. And they generally do not have the power reserves and dynamics that a good amp will give you.

cfrizz

Receiver makers lie like rugs when it comes to the power that thier receivers actually put out.

You might get that 140 if you are just running 2 channels, but when you start running 5-7 channels you'll be lucky if you are getting 50-60wpc!

Then toss in a couple of explosions & you could easily toast those beautiful, EXPENSIVE 4ohms LSI's!!!

More than one person has come on here talking about a blown tweeter in thier brand new LSI's from playing them too loud on an insufficient receiver.

We are simply telling you the expensive truth about owning the LSI series. We are trying to help you get the best for your money that will allow you to run your speakers to thier full potential.

cathpah wrote: »

ok...then I guess I am a bit confused. If my current avr can put out 140 wpc @ 8 ohms, then why do i need another amp? or am i mistaken on those stats?

Logic 7

cfrizz wrote: »

Receiver makers lie like rugs when it comes to the power that thier receivers actually put out.

You might get that 140 if you are just running 2 channels, but when you start running 5-7 channels you'll be lucky if you are getting 50-60wpc!

This above statement is only true if the rating was taken at 1K. The Denon receiver in question was given its rating at 20-20,000hz.

WilliamM2

Logic 7 wrote: »

This above statement is only true if the rating was taken at 1K. The Denon receiver in question was given its rating at 20-20,000hz.

Not true. They rate them with only two channels driven, they do have less power when all 7 channels are used. Have you ever seen the bench results of most recievers?

BTW, what do you have to sell?

VXR8

I too have the 3808 plus the LSi9s as mains. I recently was utilising a Rotel RB-991 200 watts RMS x 2 into 8 ohm to drive the LSI9s. I am currently selling that amp to purchase either the Emotiva XPA-2 and XPA-5, or the MPS-2 amplifier. I have noticed since running the LSis through the receiver only, in 2 channel that the sound quality isn't as clean, the bass not so pronounced and tight and know I am not going to push the limits until I replace with any of the above amps. The Emotiva gear is great bang for buck ($799 each USD for XPA-2 and the XPA-5 and $1699 for the MPS-2). You don't realise how much an amp improves the sound until you take it away.

Good luck with your endeavours.

Logic 7

WilliamM2 wrote: »

Not true. They rate them with only two channels driven, they do have less power when all 7 channels are used.

This not always the case

WilliamM2 wrote: »

Have you ever seen the bench results of most recievers?

Many times. This maybe true on a lot of receivers maybe but not all.

WilliamM2 wrote: »

BTW, what do you have to sell?

Well I was recomended this site by someone. Maybe they were wrong. I dont have enough post to sell anything.

Kex

Calm down Logic 7! What people are trying to point out to the O.P. and cathpah are that most receivers' w/ch ratings are bloated. Usually because, as I am sure you know already since you seem quite knowledgeable on the subject, they are only rated at two channels driven and in almost ideal circumstances that will never compare to true usage.

Onkyo, at least, are completely honest about this, and clearly state in their specifications that they are measuring two channels driven, not five or seven. Most others are not. Noteworthy exceptions are harman/kardon, NAD (and Marantz, IIRC), and I am sure there are others. Denon or Yamaha receivers do not generally perform that well in bench tests. It is not unusual to see receivers costing $1,000 or more, and claiming well over 100w/ch, to output the same or less, in bench tests, all channels driven, than a harman/kardon costing less than $500 and claiming only 40w or 50w/ch.

It is not always true either, though, that entry level amplifiers will yield a "night and day" experience in comparison, as I learned when I blind tested an entry level Emotiva amplifier with an entry level harman/kardon. I kept the harman/kardon and got rid of the Emotiva.

zx_toth

In my opinion it is not worth risking your expensive gear by improperly running them. Sure you can get away with a lot of things in life, like speeding in car, swiping a pen here and there from work but some of it might get you in trouble eventually and when that trouble is blowing a tweeter in your LSis or shortening the life expectancy of your Denon 3808 dont cry to the Manufacterurs of the speakers or recievers or on this forum when they cease to function properly or your warranty us not honored because of not properly setting up your equipment.

Z

cfrizz

bingo!!!!

zx_toth wrote: »

in my opinion it is not worth risking your expensive gear by improperly running them. Sure you can get away with a lot of things in life, like speeding in car, swiping a pen here and there from work but some of it might get you in trouble eventually and when that trouble is blowing a tweeter in your lsis or shortening the life expectancy of your denon 3808 dont cry to the manufacterurs of the speakers or recievers or on this forum when they cease to function properly or your warranty us not honored because of not properly setting up your equipment.

Z