When the 4-ohm M&K THX certified speakers (setup in true 7.1 configuration!!!), I re-ran the MCACC and played from its derived settings and not one problem, even under a lot of volume. This made me happy as a clam ith the amplification abilities of my 2nd 45TX. So, if anyone is wondering if this receiver can handle the truth, it can!
So, the 45TX's that are manufactured in or after October, 2002 should be just fine. But you should keep in your mind that Pioneer does not guarantee proper operation with 4-ohm speakers, either in the specs or when I specifically asked about it in an email to their Tokyo headquarters. They flatly said that they would recommend 6-ohm and above, period.
That said, my 45TX is driving my 4-ohm Hales without a problem.
if you do a little digging like I did then you would already know the answer
short answer- YES. reason?- because the M&Ks are THX specific with 80hz crossover. therefore MACC doesnt have to boost the 62hz point. It also says that in the manual. if you are having any shutdown problems....
but it really depends on your setup. how large is your room? how much gain are you going to put into the speakers? are you running all 7 channels? what does your MACC show in terms of adjustments? how do you have the M&Ks configured- because they CAN be configured to run in 2ohms if you read the manual on the speakers as well.
My friend was able to shutdown the denon 5800 with a maggie HT setup- but any sensible person would already expect that
here are some answers to your questions: 1) my room is narrow 26 ft. x 12.5 ft. 2) Gain...? help, only gain I know is Screen gain LOL 3.) I will be running a 6.1 system 4.) I don't own the the 45 yet could not tell you the MACC adjustments 5.) I plan to run the M&K's at 4 ohms.
Excellent questions, please engage. thank you for your time. What does this information tell you.
IMO 4 ohm speakers are best driven with a separate amp. If you must use a receiver I recommend a H/K. The THX 80 Hz crossover is for sub/sat, not the speaker's internal crossover, whichis probably closer to 2k Hz. If you cross over with your sub at 80 Hz you should be okay, even with the Pioneer, considering your room is not overly large.
You might give a call or email M&K support. I have the S-150 setup and I asked for recommendations about receivers/separates from technical support. I got hold of an engineer and asked about the whole 4 ohm issue. He provided a very detailed reply on the subject. In the end, he stated that the ratings on the speakers were very conservative and that they really rated nominally at 6 ohms.
Why go to the expense of a separate amp, unless you already own the Pioneer. The Denon 5803 will handle your 4ohm loads easily (i use 2 sets Totem Model 1) and has 170wperch driven simultaneously. It warns about loads lower than 4 ohms at high volumes for long periods of time.
It also has 2 sets of 8ch analogue in's
With the Pioneer it should not matter how many channels are being used at once if it has the 7 separate amps and is rated as (all channels driven)
A forum community dedicated to home theater owners and enthusiasts. Come join the discussion about home audio/video, TVs, projectors, screens, receivers, speakers, projects, DIY’s, product reviews, accessories, classifieds, and more!