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Discussion Starter · #1 ·
I'll try to keep it short. My setup:

Onkyo sr-tx 705
Polk Audio Lsi 15
Polk Audio Lsi C
Polk Audio Surrounds 2 pair


Question is I really have to turn the Onkyo way up to get a solid loud sound in all types of media, bluray, DTV, MP3 etc. Does this issue have something to do with the speakers nominal impedance being 4ohms and the reciever not being able to power these speakers? The reason I am asking is because I will be upgrading the A/V receiver soon.


Thanks
 

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First off, please describe what you mean by 'way up', in terms of where your volume setting is at when it's loud, either using absolute or relative volume. If the output really is lower than it should be, that would have nothing to do with four ohm speakers. We'd need more information to make an accurate guess as to your problems, if any.
 

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Have you properly setup Audyssey? That has a major effect on overall performance. I've got the 705 and seriously doubt your having any power issues with it, especially at low volume levels. It should be more than capable of pushing 4ohm speakers at anything but ear bleeding volume levels.


Are you using Dynamic EQ. If not try it. It restores the dynamics at normal and lower volume levels. It has some ill side effects like pushing the surrounds level to high but once you iron those out Dynamic EQ sounds sweet.
 

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Thee Polk Lsi series are known to be quite power hungry. Go to the Polk audio forum (at Polkaudio.com) to verify this.


I used to have a pair of Lsi 9's and just felt like I wasn't getting everything out of them with my 100 watt Rotel amp. Bought a used B&K EX-442 power amp (350 [email protected] ohms) for them - problem solved.


I no longer have the Lsi 9's, but I do still have a LSI C and I power it with that same old B&K and it sounds great.
 

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Discussion Starter · #5 ·
When I mean volume up alot I mean like all the way to -20 to get a good sound. Like -10 and down for blu ray movies. The volume starts at -60 I believe so its quite a jump to get some sound. Now even at high levels it sounds great.


Also I dont believe the 705 has Dynamic EQ does it? And yeah audessey was run and has calibrated the speakers.


So I may need an additional amp to push these monsters? or can I get away with a powerful new reciever?


Thanks guys.
 

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Buying a good quality amp is always a sound investment - pun intended. It will in your system long after your present AVR is just a faded memory.
 

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While the 705 is supposed to be capable, your Polks like a previous poster said, are indeed known to be quite power hungry.


Do check out the Polk thread and Club Polk forum for more info.
 

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I have almost exactly the same setup for speakers (only 5 speakers) that were hooked up to a Pio Elite for several years. Recently picked up an Emotiva XPA-5 (5 x 350 wpc @4 ohm) and have noticed CONSIDERABLY more punch out of them, especially with bass. Despite already having a superb SVS PC+ sub.


I had to crank down the volume when watching Cloverfield, for fear I was going to get stomped on...


So I can say from personal experience, that you can definitely benefit significantly from an external amp. Going with a better AVR is unlikely to change this since most of the amps in AVRs are either not rated or not recommended for use with 4 ohm speakers. Also a good external amp will have an even greater advantage in power output into a 4 ohm load, relative to the amps in an AVR than it does at 8 ohms.


Onkyo does list decent specs for the amps, but they only list output ratings for 1 channel or 2 channels driven. Which means they are certainly playing games with the numbers.


A decent external amp for your setup can definitely benefit you. Though it's probably not necessary to get a full 7 channel amp. Past 5 channels on an amp the prices go up dramatically and the amps in the 705 should be fine for driving 2 of the surround speakers.


Are you looking at replacing the AVR to get more power or the latest bells and whistles? If you can wait a couple of months, the Emotiva UMC-1 looks to be a killer Pre-Pro and paired with one of their amps should make for a terrific setup.
 

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Quote:
Originally Posted by bigdep /forum/post/15568052



Question is I really have to turn the Onkyo way up to get a solid loud sound in all types of media, bluray, DTV, MP3 etc.

Thanks

This is very normal for most setups. The receiver is not way up at -20. It may seem that way but it's not true. That would be a very average volume. I have a Denon 987 with Infinity Primus speakers. My average TV volume is between -22 and -15db. I watch DVDs and Blurays at -13 to -8 db. nothing wrong with your setup.


Good luck...

 

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Volume is not absolute. It's dependent on the level of the source. The more important question is whether you can achieve the desired SPL ( Sound Pressure Level) without distortion.


0 dB is not necessarily your maximum volume either.
 

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I'm honestly surprised the Onkyo powers the LSi speakers you have without shutting down at high levels. I'd say you'd be doing good to add an external amp to drive them. The Emotiva XPA-3 is a killer deal at $499 right now. Even something as simple/cheap as a used Rotel RB-971 to power the mains would take a lot of strain off of the Onkyo's internal amps.


As for the volume levels, my listening (Onkyo SR805, Swans speakers) is usually -20 for TV, -15 to -10 for BD/HD-DVD depending on how loud I want it... I occasionally take it up to -5 for demo of if I'm just feeling silly. The levels you're seeing are normal.
 

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Discussion Starter · #12 ·
Thanks for the help again! I'm still a bit confused on what is the best course of action here. Your answers are a bit contradicting. Obviously it depends on the use but if I add the Emotiva XPA-3 and keep the 705 I'll see a big jump in performance or just power? The reason I am considering upgrading the receiver is really the power / clarity issues. I love the sound just think its lacking something.


The receiver is pushing 4ohms to all speakers so I dont know if this is a normal issue or a system begging for more power.
 

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I can see how my response could be seen as contradictory... my first paragraph was about amplification power and how you could benefit from an external amplifier given those speakers' impedance and reputation for needing a lot of power. My second paragraph was commenting more on the volume scale and that the numbers you are seeing are normal... but even then, you would likely hear a notable difference in sound quality at all but the lowest levels by adding an amp that can feed your power hungry speakers extremely clean power.


Do you have your receiver in 4ohm mode? If so, it is limiting the amount of current sent to the amps and choking the power... from the S&V review of the SR706, I'd say you're getting somewhere around 70w max with 4ohm speakers and the receiver in 4ohm mode.
 

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Quote:
Originally Posted by bigdep /forum/post/15573613


Thanks for the help again! I'm still a bit confused on what is the best course of action here. Your answers are a bit contracting. Obviously it depends on the use but if I add the Emotiva XPA-3 and keep the 705 I'll see a big jump in performance or just power? The reason I am considering upgrading the receiver is really the power / clarity issues. I love the sound just think its lacking something.


The receiver is pushing 4ohms to all speakers so I dont know if this is a normal issue or a system begging for more power.

Short answer is that "Yes, you can benefit from a good external amp". But only your LSi15's and LSiC are going to benefit substantially from an amp. So just get an amp to run them and run your surrounds off of the AVR.
 

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Discussion Starter · #15 ·
Thanks for the clear answers. I think I will add an amp for the front atleast. Any recommendations?


Also if I drop the Onkyo to 6ohms will I hear a difference in sq and power?


Thanks again
 

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If you put the Onkyo in 6ohm mode (instead of 4ohm mode) you should have more power headroom available, but driving a 4ohm load could cause increased heat and/or clipping when the power supply can't keep up with the demands for current. There are very few AVRs that properly drive 4ohm loads without some sort of current limiting... I can't think of any in the same price class as the SR705. This makes a good amp, at least for the mains or front three, a very wise investment.
 

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Quote:
Originally Posted by bigdep /forum/post/15570619


Also I dont believe the 705 has Dynamic EQ does it? And yeah audessey was run and has calibrated the speakers.


Thanks guys.

My bad, I was thinking 706.
 

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Discussion Starter · #18 ·
Alright so a few more questions after some research. Since I dont have a time frame really and I am intriged about the Emotiva UMC-1. Should I purchase the 7 channel amp in preperation for the UMC-1? Or just stick with the 3 channel. Also is there a way to preorder the device? Also i've searched for a release date for the umc-1 and havent really found much. Seems its been pushed back several times already.


Also anyone know how long the current sale is going on at emotiva?


Thankks guys
 

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Quote:
Originally Posted by bigdep /forum/post/15578733


Alright so a few more questions after some research. Since I dont have a time frame really and I am intriged about the Emotiva UMC-1. Should I purchase the 7 channel amp in preperation for the UMC-1? Or just stick with the 3 channel. Also is there a way to preorder the device? Also i've searched for a release date for the umc-1 and havent really found much. Seems its been pushed back several times already.


Also anyone know how long the current sale is going on at emotiva?


Thankks guys

AFAIK the current sale is til the Super Bowl I believe. Shipping is normally something on the order of $75 for the XPA-5/3 or something like that.


If you are going 7 channel and getting a new pre-pro, that changes what you might want in an amp. The cheapest 200 wpc x7 amps seem to be $1,500-1,700 minimum and you don't need 200 wpc for your surrounds. So I would probably go with the XPA-5 and the UPA-2 (for the remaining surrounds), but you can always hold off on the UPA-2 until you get the UMC-1 or even just keep using your Onkyo for them. The XPA-5 + UPA-2 is only like $100 more than the XPA-3 and 2 UPA-2s. Plus it's one less piece of hardware.


The UMC-1 is due out some time in the next couple weeks. Hopefully before the end of Feb. Maybe before the end of Jan, but more likely sometime in early Feb. Unfortunately, the pre-orders are all sold out. So you would be looking at something like 3 months after the initial batch comes in to get one. Though there's going to be a certain number of the pre-orders cancelled in anticipation of the higher end XMC-1 (likely about $1000). But that isn't due out until summer at the earliest.
 

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Your SR705 is a solid processor and shouldn't have trouble driving your surrounds. I would give just the XPA-3 a try first and wait to see how the actual UMC-1 time line pans out... it's been delayed several times, it could happen again. If the UMC-1 does become available and you still want it, a pair of UPA-2s should be more than enough for your surrounds.
 
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