Originally Posted by bigro
Hello, I am an AVSforum Noob here. I have been Prowling around to get Info on the Debut series when they were announced and Now I see the Uni Fi being announced. I have noticed some comparing the Debut to the Uni-fi . I just wanted to point out that I believe the Debut's are rated at 6 Ohms and the Uni-Fi are rated at 4 Ohms. I am not up on HT amps and gear as I mostly play in the 2 Channel Arena where many amps will work at 4 Ohms. Looking at the specs on some of the lower end Sony HT Amps there is really No Specs on Impedance or any of the typical specs I am used to with a 2 channel amp just a bunch of fluff about the massive amounts of things you can plug in or stream,. Pioneer does list "Guaranteed Impedance" at 6- 16 Ohms on their entry level receiver. Harmon Kardon Seems to list power specs at 6 and 8 Ohms. Oddly it seems they only mention max specs at 2 channels and not what the output of each channel is. Is this is the norm for HT receivers? If so that's fine. I find it odd though. In any Event it seems the Debut line Falls within the Range of some of these random entry level amps when it comes to impedance but the Uni Fi Does not. All my amps are rated at 4 ohm so this does not affect me if I can bring My self to sell the B6's I have to upgrade. I am curious however if the seeming lack of specs on the actual audio portions of these Home theater receivers and the focus on all of the new features and things you can plug in( from my point of view )can be misleading in that these amps may just play fine with 4Ohm Loads but it is just not stated.
If no one has said so, welcome to AVS!
You might want to refer to post number 176
by the man himself (Andrew Jones) as he explained very well on how the Uni-FI B5 are rated for the nominal impedance of 4 ohms. Andrew actually gives the basis of how he determines the nominal rating of the speakers he designs, so it's a worthwhile read.
The vast majority of modern multi-channel HT receivers have their power output rated for 8 ohms nominal load into 2-channel "solid" stereo mode. Some manufacturers are nice enough to specify the frequency range such as 20Hz to 20kHz and advise the maximum THD as well. Not all do this, so buyer beware.
Bench testing for more than 2-channels is done normally in a separate review and as expected, the power drops off from the 2-channel specs. 5-channels driven may drop down to 70%, all 7-channels driven may drop further to 60%, etc. The trend is the more channels driven means lower per channel output. This is the norm for all modern HT receivers.
Even though modern HT receiver isn't rated for 4 ohms, the vast majority can drive the Uni-FI B5 up to moderate listening levels. Once you've employed bass management by directing the power hungry low frequencies to the more capable subs, most likely the loud reference level can be achieved.