Tonearm microphonics

Dear @handymann : Do you own other LOMC cartridge you can test on that TT/tonearm?.
I'm not talking that you make tests with other cartridge tapping the TT but just listen at those SPL with LP recordings that has high low bass.

Btw, which cartridge did you use it before the XV-1s where I could think you did not aware of the problem or you had it?

I think that first than all is to be aware if those high low bass room SPL affects the racks you are using in the system. Remember that at room corners low bass SPL is " concentrated " and with subwoofers that goes as low 10hz or even lower with high SPL at the volume its distortion levels goes higher than normal . In other side maybe the subs are reproducing low bass oscilations that comes elsewhere from the system but I can't be sure on this.

The plinth tapping is non adequated test for your problem rigth now. First you have to identify where is generated the problem and depending this will be the solution or solutions.

Even maybe some friend (s ) can borrow you other cartridges to make those tests. Repeat not tapping.

You can check too that at those SPL/volume gain running the VPI TT but with the tonearm/cartridge at rest:  take a look to the subwoofer drivers if exist any movement there or at the speakers woofers.

After those tests you and us can have a better " stage " of what's happening before to follow at " blind " way.


Regards and enjoy the MUSIC NOT DISTORTIONS,
R.

Hi Raul:
I've seen your name mentioned in several discussions, but don't know anything about you and really don't need to.  From other's comments, people look to you for advice.  I'm 63 years young and have been into sound since I was four.  I was given a "real" record player for Christmas and after seeing my uncle string speakers across my grandparents room, went home and disassembled my record player, to see if I could do the same.  My dad bought me a 4" speaker to play with and I've been hooked ever since.  I'm going to address some of your questions, but I need to give you info about my equipment and room.  It's 19' x 21' x 10' high.  I have a dropped acoustic tile ceiling that's about twelve inches lower, with 8" fiberglass batts resting on that.  I have about 12 acoustic panels made of 1" hard fiberglass, covered with speaker cloth, that are on the 45 degree walls leading up to the ceiling (jump ahead to get a description of the walls) and are 2" out from the wall itself. I have 4 home made ASC-like tube traps strategically placed.  I think my room is too small, for the energy I'm trying to introduce in it.  I'm using 2 Fathom 113 subs that are diagonally placed, almost facing each other, about 4-5' out from each corner, with one being set 180 degrees out of phase, to help with cancellation.  My room has knee walls aprox five feet tall, then goes into a 45 degree angle to the ceiling. The ceiling is about 8' wide. I read Jim Smith's book and decided to place my TT on the left wall, between my listening area and the speakers.  The speakers are about 8.5' apart, 3 and 4' from the side and rear walls and 9.5 feet from the listening area.  Because my floor is on the second story and is on a suspended floor,  I eventually had to separate the TT platform from the wall and using heavy duty springs, eye bolts, steel cables and turnbuckles, successfully achieved a kind of floating shelf.  No more problems with walking across the floor etc.  To your question about different carts.  I have a 1974 Pioneer PL 71 that has a Koetsu Urishi Black on it and I can run it a good 3-6 Db higher, before I get any feedback-maybe even higher than that.  I have a Sony ESD 2000 preamp I run my subs through, for convenient remote control and separate gain control.  This way, I can vary the volume of the sub, depending on what record I'm listening to.  Today I added some dampening fluid to the VPI, but it didn't seem to help. I once had a Lyra Delos on the VPI, but have added another sub since then.  I'm thinking I had the same problem then. I'm not saying I can't listen at a comfortable level, but if I turn it up, (85-90 db) I get an acoustical feedback problem.  I was told by some of the best, that's just the way it is.  I would appreciate any solace you can provide.  BTW-no woofer movement, when not playing.  Wish I could find a subsonic filter, single or double channel that would filter out 15hz and down.

The do level of the subs are around 45-50

Dear @handymann : I assume that the ARO told you that those subwoofers positions gives you " flat " bass response, rigth?

Now, in any stereo audio system with passive main speakers and powered subwoofers those main speakers must be running as " satellite " ones, this means running from around 80 hz and up and the subwoofers covering from 80 hz and down.

But even that you could have " flat " response at your seat position you need to test the response at TT position that’s where the problem is happening.

You said that you already " play " with different locations for the subs and this subs position is critical when we want that the subs be perfectly integrated to the stereo audio system.
In my case and after more than a year " playing " with the best location in my room/system is both subwoofers rigth in front of the speakers facing each to other ( not facing at seat position. ), are in a " free " space.

Now, the first and main target when we integrated a pair of powered subs in a " passive " system is that IMD/THD goes really down, first at the main speakers and as consequence of that to the whole audio system.
Second target is to improve the quality level reproduction of the bass range ( that’s the foundation of the MUSIC, it’s where MUSIC belongs. Not at the mid-range. ).
Third target is to add a half or one and half bass octave to the audio system.

Main target when subs are integrated in the system is: that we can’t " hear " those subwoofers, that we be aware of only when the recording ask for, this means that the SPL/volume subs set up must be just PERFECT and stay that way always and not be change it by us depending on the recordings we are listening: NO.

In the other side. the THD of your subwoofers is really high when its specs says around 10% at 50hz at 120db, this figure is not a good one. My Velodyne’s has 0.5% not at 50 hz but at 20 hz ! ! ! . Big and critical differences.

Try to make those tests at TT position and that main speakers only handle the frequency range from 80 hz and up, play again with subs position and critical that SPL/volume on those subs that must be fixed.

Regrads and enjoy the MUSIC NOT DISTORTIONS,
R.

Btw, 85 db at seat position is something that when subs are well integrated in the system produce no single problem. I measured SPL at my seat position over 95 dbs with out be awared of problems down there. My TTs are in between the speakers.

Hi Raul:
I have a couple of Wilson Maxx II's.  They're rated @ 20hz, but they don't quite get there.   If I place my subs in front of the speakers, won't that block my main bass?  I have had the subs facing each other before, but they were behind my speakers.  That placed them too close to the corner and overemphasized the bass.  I saw a picture of a guys room and he had his on each side of his listening chair pointed away from him.  I need to build a couple of diaphragmatic absorbers, as well as a couple QRD-13 dispersion panels.  Won't help my current problem, but may help the over all sound.  Do you incorporate these devices?
I have my sub sourced through my tape out on my Calypso preamp and have the subs rolled off around 35hz, so most of the main bass will go through my main speakers.  I kinda like to play with the sub volume, specially on old LP's where they rolled off the bass to high.  I know it's not "real", but still sounds better to me, than the rolled off sound.  When playing quality LP's and the occasional CD, I set the sub volume and leave it.  I was listening to The Thompson Twins "Through The Gap" the other day with my mains turned down low.  I heard some really good low frequency, I hadn't realized was just coming through the subs, so I think I get them matched up pretty well.  It's fun to just listen to the subs sometimes, just to hear things like that.
Sounds like your subs are really good.  Wish I had shopped around more, but mine are OK.  I'm still open to suggestions.  As I said, wish I could find a filter to block everything from around 15hz and down.