[stereo5]

I recently upgraded to the Kismet Reference speakers and I am enjoying them immensely.  Over the weekend, I decided to play some vinyl on my VPI Scout turntable with JMW 9 arm and ZU DL 103 low output mc cartridge.  To my surprize, the woofer cones were pumping in and out like crazy, as soon as the needle hit the record.  This happened even at very low volume.

I have had this turntable for 2 years and never had this problem with the Vandersteen 2CE speakers or the DeVore Gibbin 8 speakers which the Kismet replaced.  I tried various isolation devices under the turntable to no effect.  My speakers are about 26 inches from the rear wall and 5 feet from the side walls and they are sitting on spiked cones from Adonis (very expensive) and are solid on the floor under the carpeting.

I am unable to move the speakers or the Audio rack so I am kind of stuck.  Other than buying a KAB rumble filter, what else can I try?  I am told the reason for my problems is because the speaker is rear ported and my turntable is somehow picking up the low frequency's.  I am worried that this pumping of the woofer cones will damage the speakers.

Can anyone help me??

Bob

[lazydays]

two things you might try
* Move the speakers forward to where they are about three to three and one half feet off the wall, while leaving the turntablein the sameplace. These speakers seem tobe very reflective at the rear, and don't feel lonely as I'm going thru the same nighmare. But I fairly certain I've finally found the feedback source. In my case it's a new large window installed right behind my system.

* Make the port a little bit smaller in the rear. You can do this by fashioning a foam sleeve from something like 1/4" thick material. If that helps a little, then try 3/8" stuff. You'll loose some bass, but that's the trade off. Myself, I'm not a bass nut
gary

[Wayner]

Because you said it happens "even at low volumes" proves that it is not from speaker feedback. The cartridge is picking up very low frequency mechanical energy, and it is being amplified by the upstream components, ala preamp, amp and finally visible on the woofers.

The number one cause of this is cartridge mis-tracking for any number of reasons. The first I have to ask is are you sure you are not tracking too heavy for your cartridges suspension. Next, the SRA of the cartridge should be at 92 degrees and I'm wondering if this is the case. You may need to set your VTA up to get the stylus to toe-in slightly. This will create better contact and hopefully stop woofer pumping.

Wayner 

[stereo5]

I talked to a rep from ZU Audio this morning.  The optimal tracking force is 2 grams which is exactly where I have it set on my turntable.  The VTA is set according to the manufacturers suggestion and sounds best where I have it.  The SRA is exactly on the money.  I had the turntable set up at a very high end shop in Newton, Mass.  They sell tons of turntables, most much more expensive than mine.

It definitely is the speakers as I haven't had this problem until I upgraded to the Kismets.  I am unable to move the speakers out further into the room as it will block the Plasma tv and my wife would not accept that.  FM radio and cd sounds superb the way the speakers are set up.  I misspoke earlier, It happens once the sound is 83db (using Radio Shack spl  meter) and above.  The woofers just flutter like crazy with no additional output.  Many on the Vinyl Asylum recommended a KAB rumble filter or mounting the turntable to a shelf on the wall.  The wall shelf is out of the question.

I hesitate with the KAB rumble filter because it is only a 170.00 item and I would need to buy 2 more audio cords which will cost me a lot of money.  Does anyone have any other thoughts?

Bob

[TomS]

I talked to a rep from ZU Audio this morning.  The optimal tracking force is 2 grams which is exactly where I have it set on my turntable.  The VTA is set according to the manufacturers suggestion and sounds best where I have it.  The SRA is exactly on the money.  I had the turntable set up at a very high end shop in Newton, Mass.  They sell tons of turntables, most much more expensive than mine.

It definitely is the speakers as I haven't had this problem until I upgraded to the Kismets.  I am unable to move the speakers out further into the room as it will block the Plasma tv and my wife would not accept that.  FM radio and cd sounds superb the way the speakers are set up.  I misspoke earlier, It happens once the sound is 83db (using Radio Shack spl  meter) and above.  The woofers just flutter like crazy with no additional output.  Many on the Vinyl Asylum recommended a KAB rumble filter or mounting the turntable to a shelf on the wall.  The wall shelf is out of the question.

I hesitate with the KAB rumble filter because it is only a 170.00 item and I would need to buy 2 more audio cords which will cost me a lot of money.  Does anyone have any other thoughts?

Bob

Not sure I have other suggestions other than possibly confirming for you.  I had Merlin VSM-MXe's for a long time, using the same woofers, though in a front ported configuration.  Merlin uses the SBAM electronic module which provides bass eq but also implements a low frequency cutoff (rumble filter) to keep that stuff out of the woofers (like the KAB apparently does).

It might be worth a call to Klaus on this as he spins a ton of vinyl at his own place.

[djbnh]

It might be worth a call to Klaus on this as he spins a ton of vinyl at his own place.

Ditto

[jdbrian]

Hi

  You are getting low frequency energy from the turntable that is below the port tuning frequency of your speakers. Likely the problem will be worse on records that have warps. The best way to deal with it is with a subsonic filter. This is an issue with all ported systems but some are more sensitive than others depending on the tuning frequency and the amount of damping in the system below the tuning frequency. You could try blocking the ports. The SS 8545 works very well in a sealed configuration.

Brian

[lazydays]

I talked to a rep from ZU Audio this morning.  The optimal tracking force is 2 grams which is exactly where I have it set on my turntable.  The VTA is set according to the manufacturers suggestion and sounds best where I have it.  The SRA is exactly on the money.  I had the turntable set up at a very high end shop in Newton, Mass.  They sell tons of turntables, most much more expensive than mine.

It definitely is the speakers as I haven't had this problem until I upgraded to the Kismets.  I am unable to move the speakers out further into the room as it will block the Plasma tv and my wife would not accept that.  FM radio and cd sounds superb the way the speakers are set up.  I misspoke earlier, It happens once the sound is 83db (using Radio Shack spl  meter) and above.  The woofers just flutter like crazy with no additional output.  Many on the Vinyl Asylum recommended a KAB rumble filter or mounting the turntable to a shelf on the wall.  The wall shelf is out of the question.

I hesitate with the KAB rumble filter because it is only a 170.00 item and I would need to buy 2 more audio cords which will cost me a lot of money.  Does anyone have any other thoughts?

Bob

I use a Ginko Cloud under my turntable, and a seperate isolation device under the motor. This really helped the catridge out when I first started using it. At the time I was also using a D103, and hated it! Very dull and dark till I eleminated the feed back. Most folks don't realize that the very rack you are using is also a feedback gathering device. It will always have some vibration going thru it as long as you have the electricity turned on in your house (60Hz). There are pieces of equipment that can be had, that will counter act any and all kinds of vibration that are going thru your system, but on the otherhand they don't come cheap. By chance do you know anybody that's an auto mechanic? If so borrow his stethoscope, and just play the tuner or CD player at a fairly low volume. Then put the probe on the table top your turntable is resting on. Do you hear anything? Now do the samething on the tonearm at both ends. The results may scare you! Lastly is the wall behind your system bare? Is there a window behind it?
Now take a light weight blanket, and hang it on the wall behind the system with something like thumb tacks. Play it the system again as if it were what you want it to do. If the feedback goes away, you've found the source. Then you might try to borrow a pair of bass traps to see if that helps
gary

[stereo5]

After a lot of experimenting, I have decided to order the KAB rumble filter later this week.  I will insert it into the tape loop and hopefully it will solve my problems.  I will report back once it arrives and I have been able to evaluate it properly.

Bob

[chlorofille]

Hi stereo,

The Scanspeak woofer used is tuned very low in the cabinet, so it is very susceptible to subsonic frequencies excitations. I have a similar woofer used in a 2 way floorstander and whenever I watch movies with a lot of gunshots etc, I can see the cone move a hell lot even though the volume level is moderate (85dB @ 2m). Subsonic filter will be your best bet.

[drphoto]

I dunno if this will help you, but I was having a similar problem w/ my GR OB subs, once I went to vinyl. I got a 2" unfinshed maple plank and Isoblocks from Mapletree for around $85. I already had 3 of their brass triplepoint cones. Huge improvement w/ my unsuspended Rega deck. The isoblocks go under the plank and the points go under the deck.

As the OB subs output a great deal of energy toward the rear, this may mimic your rear ported speakers. (I think they are rear ported)

I posted about this in the vinyl circle. I was really pleased at how well it all worked for the money. I initially thought a rumble filter was my only way out.

Good luck.

[Ericus Rex]

Have you plugged the tonearm and cartridge numbers into a compliance calculator?

[TjMV3]

After isolating the turntable and motor,  would something like this help?

http://www.displaycasej.com/stereo_covers.html

An acrylic turntable display cover,  which completely covers the turntable.   Would that work?

[Scott F.]

Have you plugged the tonearm and cartridge numbers into a compliance calculator?

I think this is more the issue than anything.

You likely have a cart/arm compliance issue causing a low frequency oscillation with your speakers. You never noticed with the Vandersteen's because they have the sock on them. Chances are it did it with them too.

The 'rumble filter' is only going to cover up the issue. Not to mention that you just inserted more electronics in the signal path. You will likely hear a veiling of the sound and slightly weaker bass because of the filter.

If this is the case, isolation, moving speakers and sources won't do a thing to correct the issue.

You have two choices, 1) get a new cartridge 2) get the Isolator from the Cartridge Man....Oh, you could do a new arm too but that is a little extreme.

Believe it or not, the Cartridge Man's Isolator works. It takes the whole cart/arm/compliance issue right out the equation. I know its gotten slammed for its cost but this is exactly where something like this is needed.

...just my $.02...and I could be all wet so take what I just typed with a grain of salt as I didn't do the arm/cart compliance calcs.

[stereo5]

I have settled with the Rumble filter and I am satisified with the sound and what it does.  In my case, it was the right way to go.

Bob