Originally Posted by india286
But before investing in Marantz I have inquired a lot about the sensitivity of the speakers and almost all of them saying is that Marantz @ 70 watts per channel is more than enough to drive these speakers
coz speakers 98db sensitivity is very good and even 30-40 watt per channel Amp could drive them well.
I don't understand why this change of opinion now.
but really I have complain with bass
Well, just to be a bit accurate, your PM7005 is supposedly rated at 60w/ch according to the Marantz website. That's not a whole lot. However, I will give you an update on my current situation as well. I have my old Denon 5.1 receiver hooked up to my new 980's in stereo (not surround), and it is the AVR-884 model rated at 90w/ch. Now in reality, that receiver came out in the early 2000's when they exaggerated a bit on power. So, I'm guessing it is more like ~70w/ch like yours. All I can say is after about 12 hours of run time now (which isn't a lot yet), my speakers have loosened up a bit, but still has trouble with bass like yours.
Also, the depth of the sound stage is just terrible. My old Carver receiver would blow this Denon away in depth and quality of sound, along with a ton of deep rolling bass by miles. The two aren't even in the same category.
Now, I would never put my Denon in the same sound quality category as your Marantz. However, considering both are driving these speakers with roughly the same power rating, and both suffer from a lack of bass, I would say that even though your sound quality will be better than the Denon, the lack of power will hold back the ability to get a sudden demand for current to get coil movement for bass production at lower volume. Especially since they do have a total 8ohm impedence. This may be a slight inhibiting factor when a sudden draw of current is necessary for bass production out of the 8" woofers.
That's why I was saying, it may be a better idea to do one of two things.... get a stronger amp... or sell the PL-980's, and go with a really good set of bookshelf speakers on stands like the Focal Aria 906's, and a couple of 100w subs right/left daisy chained out of your amp to the bookshelfs. That will give you a specific supplied amount of power to the low end bass, and all the 60w would then go to the bookshelfs to maximize sound quality on the high end.
Also, keep in mind, the overall sensitivity of these speakers at 98db, is primarily given such a high rating because of the extremely sensitive tweeters and sealed mid range driver added to the mix. The woofers themselves are not 98db sensitive. No way, no how. In fact most 8" woofers run about 87-92db. That means that when running a lower power amp at an 8ohm impedence, it may get kind of hard to draw the sudden current needed to get those woofers really moving like you want. To get more current to the coils, you just simply need more power.