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Bass distortion-Playing LP's only,,,,please help

VPI Prime----Ortofon Black Quintet (low output moving coil cart)-----Plinius Koru Phono Pre( loading at 20 ohms/gain at 66 db)-----Parasound Halo Integrated -----Martin Logan Montis speakers which have powered bass cabinets.

Using any other source component I have absolutely no issues. When I play an LP and increase the volume past 10 O'clock which is a little loud....but not ridiculously loud-I at times get this huge wave of bass distortion. I do have bass controls on the Montis's...and I have turned them down into the negative, but I still get what I previously described occasionally. 

Any and all help would be appreciated. This doesn't always happen, but its frequent enough to drive me crazy.

Thanks in advance.

krelldog
stereo58's avatar
stereo58
3 posts
 
I agree with Mofimadness and a few others that you may be dealing with "acoustical  feedback".  I had the same issue in a console. My turntable was producing a lot of hum when using my turntable and turning the volume anywhere past 11:00. I ended up getting an amazing isolation platform from  Symposium called the ISO Segue! It solved the problem immediately- quiet as a mouse!
russmaleartist's avatar
russmaleartist
52 posts
 
Even though my turntable was on a wall bracketed shelf, I still got air-bourne feedback. The woofers, especially my subwoofers, would be oscillating, and I also saw my tonearm bouncing up and down -- not out of the groove, but it was pretty peculiar to watch.

I used a KAB rumble filter, added more methods of isolation under the turntable, even between the wall bracket and the wall itself. The only other thing that comes to mind is isolating your turntable in another room, but then you would have to get up everytime to tend to it.

Best to you in your rumble and feedback endeavors -- hope you can solve your problem.
moonglum
619 posts
 
Mains,
Townsend's research looks pretty convincing. £1400 asking price does take the breath away :O
While I was browsing the Townsend I happened to notice someone with a pair of Montis was actually using Podiums to solve the OPs problem!
It looks somewhat floppy. I'm not sure I'd risk tall speakers on it.
Nevertheless they claim good results which seem to be backed up.
cerrot's avatar
cerrot
1,700 posts
 
I would look at my tonearm alignment.  If the VTA is off, you'll get overwhelming bass.  Assuming you have a VPI unipoint arm, they are very good, but very difficult to set up.  Look at the arm as you track a record and see how it looks.  Make sure the azimuth is set correctly, the stylus is 90 degrees in the groove (cartridge isn't 'listing' to one side).  Look at the base of the tonearm and make sure that is balanced perfectly and not listing as well.   It should appear as its floating, not dragging.
pmiller115's avatar
pmiller115
97 posts
 
It has been a while since I had to deal with issues like you describe but, as one other poster suggests, this sounds like it could be a feed back issue of some sort since you may be unknowingly producing frequencies with this recording that are somewhat distinct from other recordings. I would also try changing slightly the direction of one or more or your speakers as a way of seeking to diagnose and fix the problem.
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