Which receiver (Pioneer or Yamaha) for LSi-15

brentba

Ducati Guy wrote: »

Brentba,
So let me tell you about my 1st month @ my Lsi15's and trying it out @ a brand new AVR(Onkyo 709):
The overall soundquality was "good". But the AVR shut itself down 4 times the 1st month because of overheating and/or the speakers demanding too much current from the AVR. Now the volume wasn't crazy high, it was only at moderate listening levels. But what I think really caused the AVR to shut down was the Length of time of Use, the receiver shut itself down all 4 times after about 5 hours of continuous use(so probably just too much current demand over time overworking the receiver). So I returned the AVR to Crutchfield(who by the way Has a Great 60 day Return policy). The Onkyo has specific power ratings at 8 and 6 ohms, but not 4 ohms.
So I decided to invest the money and buy an Integrated amp @ a 4 ohm power rating.
Bought a Creek Destiny 2 Integrated Amp, " >180watts@4ohms ", a British mag measured it at 200watts into 4 ohms. That was 11 months ago and it has never had to shut itself down for any reason, even with days of 7 hours of continuous use(lots of movie trilogy days). Also, the integrated amp does sound 1-2 steps better overall.
Looking back on my experience I think that the EXpensive top of the line AVR's, like the 55-lb Onkyo 5009 would drive the LSI's well, but they cost as much as expensive Integrateds and Separates.
So that was my story.

Thank you very much for this information. I appreciate you sharing this. I will very carefully try the speakers with my Yamaha receiver when they arrive and see what happens. If I experience similar results, I suppose I will have no choice but to purchase an amp now rather than later.

I have been looking around on-line for some affordable amps. The Emotiva line has been mentioned a few times here. Does anyone have any experience with the UPA-200 driving a pair of LSi's (or any other speakers). Seems like a decent amount of power for a surprisingly low price. I haven't really found any reviews of this amp on-line yet (though I haven't searched for very long either).

Thanks.

brentba

sponger wrote: »

While we're on this subject, I want some clarification too if no one minds. I understand that low ohm loads will stress an amplifier. But if a receiver has an impedance selector, does that not mean that the receiver is actually adding more impedance to the load before it hits the amp? In which case, does that not thereby reduce the stress on the amp?

The article that I cited earlier (http://www.audioholics.com/education/amplifier-technology/impedance-selector-switch-1) did a nice job of explaining the purpose of the selector switch, I think. And the author provides his opinion on whether or not it is necessary. I don't know how accurate the information is, but it seemed pretty convincing and well stated.

hertz9753

F1nut wrote: »

It reduces/restricts current and in turn, the dynamics.....not good.

True. My Onkyo 808 set to 4 ohms didn't sound good with my LSi9's. The same receiver with my Monitor 70's and CS2 actually sounded pretty good.

pyrocyborg

Well... If I can add something: anyone could fry even the best speakers with almost any receiver. I mean, use them at crazy high level for a given time, and sure it won't do them any good. Keep in consideration that 4 ohm speakers requires more power:however, at low to moderate level, they won't add too much stress until you get closer to the maximum power output (which is lower for 4 ohm speakers as they require way more power than 8 ohm speakers).

Also... please note that "moderate" level for someone is "high" for someone else, and that rooms tend to vary in size: It'll be easier to drive a pair of LSi15 @ 100 dB in a 15x15 room than in a 30x45 room.

That's why we can't tell anything except "common knowledge" and theory if you don't specify your listening level and your room size... Anyways, as I said before, while it's far from ideal, you should not have any problem driving them with a non high-end receiver at normal listening level. Just don't try to get the Theatre venue volume level, or everything could go ugly very fast.

Personnally, I haven't seen a pair of LSi being fried (I'm the only one in my family having these), but I've seen some pairs of 4 ohm speakers being destroyed by low-end receivers (300$-)... I have always wondered why no one told them that 4 ohm speakers requires a 4 ohm receiver/amp to be safe... yeah, that stinks...

Soooo, here's a little summary:
- A 4 ohm receiver isn't mandatory, but it can help if someones ever turn the knob too high or if you use it continuously. Overpowering your speakers isn't as bad as underpowering them!
- Yamaha/Pioneer: It depends on the specific model. Read some reviews and purchase the one you actually like (spec or sound-wise)
- You're trying to power towers... they require power anyways to sound at their best.
- A 4 ohm amp will make your speakers shine compared to a 8 ohm receiver with a 4 ohm switch (well, the difference could be subtle), but they'll get more power, and cleaner power that is, which is what they (the LSis) want!

sponger

So I guess it's been well established so far that an impedance selector is basically gimmicky and should only be used as a last resort. Brent was asking about affordable amps and threw out emotiva as a suggestion. Anyone have any input? I'm interested in hearing some feedback on that as well.

ravaneli

i have not seen bench test results on that particular emotiva, but the rest of their models have very reliable specs on the tests. This model actually seems to have lower distortion than the xpas and they were already good enough.

Here is the bottom line: emo has higher distortion and not as flat a frequency response as brands like parasound, rotel, bk, adcom and the more expensive ones. However there is a margin of error that the human ear cannot detect, and emo is well within that margin of error. So emo basically amplifies the signal without adding any audio signature or coloration or whatever u wana call it.

Even if the distortion of emo amps was detectable, which it is not, regardless of what H9 will tell you, or that nub finut, the frequency response of ANY speaker has 10 times wider amplitudes. Means the signature of the speaker will always completely trump the signature of the amp. fact.

another fact - emo amps are not really cheap. You are being confused because of the fact that they sell direct and are able to provide u a great price. They have similar cost and qulity to the more expensive amps and IF EMO sold the same amps through a dealer, they would all cost twice as much and then the audio snobbery, abundant around here, would regard them very high.

So i can whole heartedly recommend that amp for that purpose. You will absolutely love it and you will not for a second have the feeling you are buying a cheap knowck off. Customer service is great, i hear.

ravaneli

here are emotiva's own bench results.

http://emotiva.com/resources/media/upa200/upa200_4ohms.pdf

this is not an independent third party test, but previously the specs of emotiva have been pretty reliable. These guys don't hide anything.

Looks at the freq response graph. Flat as a ruler. If H9 tells u as he likes that emo + rta = ear bleeding tell him to jump off a high building.

Look at the noise graph too. < 0.05% in the entire range from 1w to clipping.

This amp has no input of it's own to the audio signal. The OUTPUT of this amp is its INPUT.

F1nut

Wrong......AGAIN!!!

hertz9753

ravaneli wrote: »

here are emotiva's own bench results.

http://emotiva.com/resources/media/upa200/upa200_4ohms.pdf

this is not an independent third party test, but previously the specs of emotiva have been pretty reliable. These guys don't hide anything.

Looks at the freq response graph. Flat as a ruler. If H9 tells u as he likes that emo + rta = ear bleeding tell him to jump off a high building.

Look at the noise graph too. < 0.05% in the entire range from 1w to clipping.

This amp has no input of it's own to the audio signal. The OUTPUT of this amp is its INPUT.

You remind of few people from other forums. Who are you? What equipment do have? What have you run in the past?

I don't have a promblem with Emotiva. Personaly I think there amps are pretty good.

If I told you grass is grass, what would your reply be, without a review? What do get when to take off gr in grass?

ravaneli

here is some more facts to contrast the subjective jibberish of finut and the rest with the ungodly fear of 4 ohm. I did some simple math myself. I know math is like voodoo to some people that hate grapsh and numbers and anything that would remove OPINIONS from this hobby. But someone may be interested.
W = V . I (1)
I = V / R (2) (ohm's law, finut)
from (1) and (2) ==> W = I . I . R

W = I^2 x R

So what are the implications of reducing R from 8 ohm to 4 ohm? What are the exact implications for the AVR if you want to use a 4 ohm speaker? Well in order for the AVR to provide the same watts the I^2 component will have to double, because the R component was reduced in half. But what is the exact change in I that doubles I^2 ? Let's define X the change required for the doubling of I^2. Then

(I + X)^2 = 2 I^2 - that sqrt of both sides
I + X = 1.414 I - flip the I to the right
X = 1.414I - I
X = I (1.414 - 1)
X = 0.414 I

ravaneli

so what does this mean? It means that if you want your AVR to put out the same watts with a 4 ohm speaker that it puts with a 8 ohm speaker, the current through the AVR will have to increase with X which is 41.4%

This is all. No black magic behind. No devil will destroy your AVR if you plug it to 4 ohm speakers. But if you are used to listening music at some level and want to listen at the same level with the 4 ohm speakers, the AVR will have to handle 41.4 % more current, which MAY kill it. But if you turn the volume down so the current is within the handling of the avr, you will be safe.

I just did the math myself, it can probably be improved but that's the jist of it, don't be nitty gritty

sponger

ravaneli wrote: »

So what are the implications of reducing R from 8 ohm to 4 ohm?

According to that link that Brent posted, selecting the low impedance option on a receiver to drive a 4 ohm speaker will cause the receiver to start clipping more easily. If a receiver is more likely to clip at lower volumes, then wouldn't that be more dangerous than a conventional set-up with 8 ohm speakers, etc.? And wouldn't that be more to your point?

tonyb

ravaneli wrote: »

current through the AVR will have to increase with X which is 41.4%

the AVR will have to handle 41.4 % more current, which MAY kill it. But if you turn the volume down so the current is within the handling of the avr, you will be safe.

Lets assume for one second your correct. Is there a meter to measure what current level, is "safe" ? A receiver as you say would have to put out 41% more current, but as you know, it limits current when switched to 4 or 6 ohms. What drives a 4 0hm speaker ? Current....so thank you for making our case and contradicting yours.

hertz9753

Ohm's law is required in basic electronics courses. Just saying nothing...

nguyendot

hertz9753 wrote: »

You remind of few people from other forums. Who are you? What equipment do have? What have you run in the past?

I don't have a promblem with Emotiva. Personaly I think there amps are pretty good.

If I told you grass is grass, what would your reply be, without a review? What do get when to take off gr in grass?

He runs PA amps and says they're as good as a real hi-fi amp because the distortion is "undetectable". I think he forgets about the whole picture sometimes. Correct, all the time. Just here to stir up some stuff. I commend him for sticking up for his beliefs, but the same could be said for Charles Manson.

ravaneli

i did this so you know what is happening and not attribute the 4 ohm danger to God or black magic. Your AVR may be capable of putting out 100W at 8 ohm but it will be able to put out much less than than at 4 ohm. Obviously you can't listen at the same levels as with 8 ohm speakers, but if you keep it down there is no danger for anything. What is down? That can be calculated too, i will try that tonight. Knowing that the db is a log function only a few db lower will reduce the current dramatically, but i will try to calc the exact number. No engineer here? I am an economist, this is not my specialty, but i know the basics in math and electronics. Someone could give us a more precise calculation. Perhaps you will respect his answer more than mine too.

Joe08867

Ravenelli, so you think an AVR putting out 41.4 percent more current through a power supply created for 41.4 percent less current is safe? Is that what you are saying? Wow, you scare the bejeesus out of me. How does your mind work?

Remind me never to let you do electrical work around me. EVER!!!

nguyendot

ravaneli wrote: »

i did this so you know what is happening and not attribute the 4 ohm danger to God or black magic. Your AVR may be capable of putting out 100W at 8 ohm but it will be able to put out much less than than at 4 ohm. Obviously you can't listen at the same levels as with 8 ohm speakers, but if you keep it down there is no danger for anything. What is down? That can be calculated too, i will try that tonight. Knowing that the db is a log function only a few db lower will reduce the current dramatically, but i will try to calc the exact number. No engineer here? I am an economist, this is not my specialty, but i know the basics in math and electronics. Someone could give us a more precise calculation. Perhaps you will respect his answer more than mine too.

Cool, don't forget to calculate loss to heat and the inefficiency it applies as the gear gets hotter. Pretty sure you can't calculate that without physical measurements.

pyrocyborg

Joe08867 wrote: »

Ravenelli, so you think an AVR putting out 41.4 percent more current through a power supply created for 41.4 percent less current is safe? Is that what you are saying? Wow, you scare the bejeesus out of me. How does your mind work?

Remind me never to let you do electrical work around me. EVER!!!

Well... Ravanelli is right about the power increase. I never did the math, but I expected it to be 50% at least with heat loss. Also, he never said that you should drive 4 ohm speakers with a 8 ohm receiver at 120 dB! He said that if you keep the volume lower, you shouldn't have any trouble and he's right. The problem is, your "error" margin is lower with 4 ohm speakers:

For example, you can drive your 91 dB sensitivity 8 ohms speakers to 101 dB (3 meter distance in a standard sized living room) with 50W of power without taking heat in consideration. 101 dB is pretty much too high and you cause permanent hearing impairment, as you know. A more realistic volume achieve with loss and sound dispersion would be something like 95 dB, which is high.

With the same amount of power, you can drive your 4 ohm speakers to 98.5 dB at the same distance. Even with loss, it's 89dB, which is high.

The main problem here is that the LSi aren't effective speakers: the maximum you could achieve with a 100W per ch receiver (if it really were continuous 100W, and not some overestimated spec) is 98.5dB, and at this current, it would be cliping in a few seconds. It's safest to say that you could achieve something like 97 or 96 dB without cliping early, and something like 92 or 93 dB would be a safer bet for continous play (i.e. using 30W at 4 ohm, instead of 15w at 8)... it would be 85 or 86 of real world dB: not enough to shake your house and have that theatre venue effect. As a matter of comparison, it would be louder than your crying child at the same distance...

So, it is dangerous to use 4 ohm speakers with a 8 ohm receiver: yeah, compared to using a 4 ohm amp, but still... you could still blow anything if you crank it up too much.

Also, if you redirect most of the sub 50 or 60 frequencies to your sub using the receiver crossover, you'll help the receiver a bit too.

Anyways... as he said, Emotiva amps are great for the price. Is it the best ever? No, but for the price, you can't be wrong, expecially if you start and you want new gear. If you don't mind used, you can get some pearls here and there in many brands.

ravaneli

need to redo this

ravaneli

double post (pretty sure i clicked only once)

ravaneli

need to redo

tommyt21

F1nut wrote: »

JHC, just hook up either of your AVR's to your LSi 15's, turn up the volume and find out for yourself what happens. There's your real world expereince, the only kind that really matters.

LMFAO...
I spend alot of hard earned cash on my equipment and if I was in this guys position I would not take the chance. I would listen to the guys on here that have decades of experince and knowledge. With some nice speakers like those just get a freaking amp already thats designed with power output that matches the designed power intake of the speaker.



We are all born ignorant, but one must work hard to remain stupid.
Benjamin Franklin

ravaneli

Ok, so we established that if you want to output the same Watts as with 8-ohm speaker you need 41.4% more current. But how much do you reduce the volume (in db) so that the current is what it used to be with the 8-ohm speaker?

Well since the decibel is a ratio between two powers we need to see what happens to the watts if we use the 4 ohm but the old current. So instead of W(P0) = 1.41 I^2 x 4 we want to calculate W(P1) = I^2 x 4.

Well P0 = P1 x 2 so

P1 = 1/2 P0

That means that if you plug 4 ohm speakers and want to keep the current to the levels of the 8-ohm speaker, you have to reduce the watts IN HALF. So if your AVR could safely push 100W @ 8 ohm, it can only push 50W at 4 ohm.

How do u reduce the power in half?



P1/P0 = 1/2

Ldb = 10 Log10 (1/2) = 10 x (-0.3) = -3 db

So reducing the volume by 3 db will half the power output of the AVR and will ensure you are at the old current levels.

ravaneli

you know, besides the personal insults there is another insult here. You people keep hanging the straw man and you think you are so smart that the rest of us can't see. If you don't know what straw man is - look it up. You go and repeat something that nobody is disputing, and somehow that makes a clueless sould like tommyt smart and I, the fool that bothers to do math and put things in quantitative perspective, I am the stupid. Nobody is disputing that amp is better than avr. If someone is - please point who. The argument was that everyone tried to scare the OP that using his AVR for those speakers = 'plain suicide', 'personal forest fire' and what not. Now if you lack the intelligence to keep track of the real discussion please refrain from insulting others. little tommyt who learned nothing first hand but only heresay from these 'reputable' sources around has the nerve to go call others stupid

And while I am at it - no, the upgrade from A4 to A6 is not, what did you call it - MONSTROUS. It is utterly preposterous for one to suggest so. How could that possibly be? How would you then describe the upgrade from CS10 to A6? You are a little lose with the use of words, sir, no?

tommyt21

Ravi, i did not call anyone stupid and yes I respect much of the advice I have gotten on this forum, and in my experince has helped me put together one hell of a system that i'm very proud of. With my qoute I simply am pointing out that if you dont attempt to take advice and learn you are doing the opposite.

I'm not the smartest tool in the shed, but from what I understand when you ask a reciever or amp to push a 4ohm load you need a increase in current. I would imagine then if a reciever is designed for a 8ohm load its power supply and internal circuitry most likley isnt designed for the current requirements of a 4ohm load.

Could you possibly cause a fire by overloading your reciever like this ??


Found this website had a great explanation of 4ohm vs 8ohm speaker loads.
http://www.prestonelectronics.com/audio/Impedance.htm

Joe08867

I was not attacking. You are just not understanding why we are warning him.

While the AVR he is using may be able to run the speakers it may not be safe for the speakers, AVR or possibly if all heck breaks loose the home they are in.

Telling someone they are fine running 4ohm speakers off an AVR not designed to do so is bad advice. While it may be a temporary solution it could be a costly one. That is why we tell people what we do. Get it now. It's not about keep the volume in check and you will be fine. Dynamic passages in music at even super low volumes can tax an AVR not up to the task. Which in turn can easily blow tweeters and drivers as well as the AVR.

brentba

tommyt21 wrote: »

LMFAO...
I spend alot of hard earned cash on my equipment and if I was in this guys position I would not take the chance. I would listen to the guys on here that have decades of experince and knowledge. With some nice speakers like those just get a freaking amp already thats designed with power output that matches the designed power intake of the speaker.



We are all born ignorant, but one must work hard to remain stupid.
Benjamin Franklin

Once again, please allow me to explain myself because posts like tommyt21's make it clear that I am being misunderstood.

I am in NO WAY against purchasing a 4-ohm capable amplifier. In fact, I agree 100% that this is the best way to get the most out of the Polk LSi speakers. I fully intend on purchasing an amplifier in the very near future.

My intention for starting this thread was not to start a discussion on whether or not it is safe to power 4-ohm speakers with an A/V receiver. However, when strong claims were made indicating that there is a strong possibility of damaging my equipment, I felt the need to probe the issue a little more. After all, if there really is a real world chance of damaging my receiver and/or speakers or even causing a fire, then I certainly would not want to take that chance.

I have come to my own personal conclusion, based on information presented both here and elsewhere, that the risk of damage to the speakers or receiver is minimal if proper caution is exercised. Therefore, when the speakers arrive next Wednesday (very excited!!!) I will hook them up to my Yamaha receiver and enjoy listening to them at gentle levels. In the meantime, I will do extensive research on amplifiers and when I have found one that I feel provides the best performance and value, I will make the purchase. Then I will hook up the new amplifier to the LSi speakers and enjoy the resultant improved performance of the speakers.

A lot of this thread has been devoted to bashing ravaneli. However, regardless of the accuracy or inaccuracy of his technical claims, he is the only one who seems to understand my position (based on his most recent post). I kind of feel bad for the guy (although I guess I haven't gotten to know him as well as the rest of you).

Brent

tommyt21

Good Luck to ya Brent and I hope everything works well. Congrats on some really nice speakers!

brentba

tommyt21 wrote: »

Good Luck to ya Brent and I hope everything works well. Congrats on some really nice speakers!

Thanks, man! The freight company called today and scheduled delivery for next Wednesday. I'm very excited.

I'll let everyone know how it works out. And when I get the new amplifier, I'll post my thoughts on the before and after performance of the speakers (unless, of course, the speakers get fried beforehand. In which case I will return to the forum with my tail between my legs and humbly admit defeat :redface: )