My MK Sound 4 OHM Speakers Are Hungry -- Help me feed them

I was recently on an amplifier quest myself. If I was in your shoes I would begin by upgrading my amplifier first and when I had more money upgrade to a separate pre/pro.

You didn't mention your budget for an amplifier only for a new receiver. I would recommend increasing your budget to ~$1200 to get a nice amplifier with balanced inputs and 7 channels so that you can accommodate future upgrades (or you can bi-amp your fronts).

Emotiva receives a lot of praise around here. I had a bad experience with a very nasty sales rep about 2 years ago when I was a prospective subwoofer buyer. Needless to say they lost my business for life. Others have had great experiences so don't let my singular experience deter you, but they will not receive a recommendation from me.

I would hit the used market to find an amplifier:

If your budget is around $800 (per you receiver budget and is not increasing anytime soon) I would pick up a Sunfire Cinema Grand 5 channel amp used. You probably could find one for around $700.

If this Arcam FMJ P7 stays low (http://www.ebay.com/itm/Arcam-FMJ-P7-Multichannel-Theater-Surround-Amplifier-/330866538788?pt=US_Home_Audio_Amplifiers_Preamps&hash=item4d092eb924) that would be a steal at any price sub $1k.

If your budget has some wiggle room then you should consider:

NAD M25
Lexicon CX-7
B&K 200.7
Sherbourn 7/2100a

Also please use caution with your current amp, if your are indeed under powering your new speakers and your amplifier is clipping they could be damaged!

If you can't tell then they most likely aren't damaged. The main concern from clipping your amplifier would be a blown tweeter (which is pretty easy to discern). Just search these forums about clipping, blown tweeter and power speakers, you will become an expert in no time . One indicator if your receiver is under duress would be the heat coming from it after a few minutes of use, if it uncomfortable to rest your hand on it you have a problem (if it is not hot that is not to say your speakers can't benefit from an upgraded power source). Your front speakers (where most of the action is going to take place) have a decent sensitivity at 88.5dB, so it shouldn't take to much of a beast to power them. I really would not be comfortable powering 4ohm speakers with a receiver solution (especially an $800 one at that). Maybe others could chime in, however, I would defiantly go separates and upgrade your pre/pro when you get more cash.

For the time being you certainly shouldn't 'crank' your system given your current set-up. If the amp isn't getting too hot I do not see a problem running it at reasonable levels.

Your fronts frequency response on the low end is rated at 100Hz. This is quite high. If I were you I would play around with the crossover settings on my receiver. You are in a tricky situation though since your LCR speakers are rated at 100Hz you would at a minimum want the crossover to the sub to be 100Hz (probably higher as SPL at spec limits diminishes; at-least in my experience). My guess is the reason your movie felt flat is because your crossover is probably set around 60Hz or 80Hz right now and you are loosing quite a bit of frequency information or it is being played too quietly for you to receive the impact you want.

This is a double edged sword though as the result of setting a higher crossover frequency (especially 80+Hz) may result in 'boomy' bass as most subwoofers are optimized for extreme lower frequencies.

The best way to proceed would be to play around with some of your favorite music tracks and movie scenes to achieve the sound you want and find a happy medium.

Like I said before, I wouldn't recommend using an AVR for a 4ohm speaker set-up... of the two receivers listed I probably would take the pioneer as pioneer claims it is capable of powering 4ohm loads. Looking at its spec sheet on Pioneer it is quite disconcerting that the power into 4ohms isn't listed (only 8/6 ohms are); especially for a product that is pushing its class D amp 'Unlike regular amps, Class D3 amplifiers are 4-OHM certified so they safely power those low-impedance speakers that other receivers just can’t handle.'

The Onkyo can't handle 4ohm loads (http://www.avsforum.com/t/1412714/onkyo-tx-nr818-official-owners-thread-discussion/540): someone wrote Onkyo asking if they could power a 4ohm speaker set-up with it and the answer was no.

Maybe someone else could chime in to offer you more advice on receiver selection; for me it is a no brainier to go with an external amplifier. I seriously doubt your home theater quest is going to leave you here with your MK speakers for the long term. Do yourself a favor, get an external amp that is capable and will be able to last you on your audio journey. Do you want a band-aid or a long term solution to your amplification needs

What did you expect to get when you post on a forum lol? If you didn't want opinions then you wouldn't be here in the first place Ohms law: V=IR, you drop the resistance for the same voltage output at your receiver your current is going to increase.... a lot of AVRs are built with the mainstream in mind a la receivers designed for 8ohm loads. They won't be able to handle this increase in current gracefully nor will most mid-range AVRs in your price range. It all comes down to current drive, wattage is squat.... I will take a 10W amplifier with excellent current drive for the most hungry speakers over a 1.21 gigawatt AVR haha.

So when a receiver touts 4ohm capable loads (such as the Pioneer you mentioned above) and doesn't include the power output at 4ohms all channels driven... this worries me.

This is about all I have to offer and make of it what you will. Good luck on finding a solution that makes you happy and will integrate well into your system
Edited by Todeseng3l - 2/5/13 at 8:40am

Having reading comprehension problems? ;-)

http://www.avsforum.com/t/1412714/onkyo-tx-nr818-official-owners-thread-discussion/540#post_22137573

"They (Onkyo) said so long as all my speakers are 4 Ohm and the receiver is set to drive them, it will be fine."

This is followed by something that makes no sense at all:

"You cannot mix 4 Ohm and 6 to 8 Ohm speakers."

I presume that the first sentence was a paraphrase of something that Onkyo said, and the second sentence was the poster's own personal misapprehension.

Those are not my personal opinions, but verifiable facts. There is a lot of misapprehension about AVRs and 4 ohm speakers. For example, it turns out that even the lowest end of the Yamaha AVR line (RX 373) is rated for 2 ohm loads:

http://usa.yamaha.com/products/audio-visual/av-receivers-amps/rx/rx-v373_black_u/

Dynamic Power (IHF)
[U.S.A. and Canada models]
Front L/R (8/6/4/2 ) ..................................110/130/160/180 W
[Other models]
Front L/R (6/4/2 ) ............................................110/130/150 W

Haha yeah I guess I do! One of the pitfalls of multitasking at work

Pioneer SC-1222K is 4ohm certified, it delivers 190 W/ch (1 kHz, THD 1 % @ 4 ohms). You can find those numbers in the third line of the SC-1222K Product Sheet.

Regards
Edited by okibcn - 2/7/13 at 9:05am