TT & subs = Rumble/woofer pumping?

[risabet]

The table is on my rack, top shelf centered between the speakers/subs. There is about 4.5ft from table to each sub. The front plane of the subs is about 6 inches in front of the table. I'm using some AudioQuest Viper ICs I had on hand and the TT is grounded to the pre. The ground has no impact on the pumping as I've tried both configurations.

Searching the web has given me a few ideas.
1. Isolate the table. Wall mount and or sand box
2. Use of a rumble filter. KAB RF-1 is the most noted
3. Move table.

I understand the first two. But what I could not nail down is how long of an IC can be used between TT and pre?

If any of you guys can give me some other suggestions, I'm all ears!

You could not have picked a worse place for your TT.

1. The center point between the subs is where the bass pressure is highest, especially right next to the wall.

2. If your rack is big and filled with heavy gear, a light, non-suspended TT like the Project 1 will be at a severe disadvantage mechanically, easily subject to both mechanical and acoustic feedback.

Try this to minimize both issues. While playing something with good sustained low bass, walk around at the gear end of the room and listen for the weakest bass response between the woofers, you could also use a SPL meter to the same effect. Find some light table (Ikea's Lack comes to mind for cheap) and place it at this point. Stick the TT on said table and take a listen.

 

[twich54]

with bass below 16Hz, not that I can reproduce it, but I have heard it on systems that can.

Gulp....... hear it....are you sure you don't mean 'feel it' ??

I'm curious, what organ was it ? Living in the Philly area (home to the worlds largest pipe organ) I was wondering if it as the Wanamaker organ.

 

[kach22i]

I can jump up and down right in front of it ( as my daughters love to do, especially the 4 yo.) and no problem.

I left you a comment in the Member's Systems area, but will repost here.
http://www.martinloganowners.com/forum/showthread.php?t=350&page=3

Robert, how is the subwoofer hooked up to the system?

Does your room have a concrete ground slab floor?

 

[Jeff Zaret]

Many suggestions here to say the least. I believe it is the turntable where your problem is at this point. Is it not a bad turntable . Yes better tables have better isolation. Good points made by Jeff (TonePub) as to dust covers accentuating noise in the form of rumble. If you can take it off while playing great, if not, get a nice hardbound book with some weight and set it on the cover and see what that does to alter the sound.

The turntable is picking up frequencies from a combination of places. It will pick it up from vinyl because, as Jeff said, it is very rare you will find a flat record. Now most records are fine but there is some noise there but minimal. The is the noise from the motor and/or spindle which gets transmitted through the table, possibly to the platter or plinth and picked up through the arm and then the cartridge. This is another place where most rumble occurs.

There are many methods to reduce this and you have found some and heard a lot from others. I would start slowly and note what changes are made and what these changes do to the sound. If you tap on the "platform" where the table is sitting that this first place to start. You need to isolate the table from the platform. There are man methods to accomplish this and you did mention a sandbox as one. I had this on my Thorens and although there was a little bit in my Thorens with it's floating suspension (you really had to listen for it) it did tighten up the bass.

I would try a few different things but I think isolating it would be the first step. I do not want to discourage you. It will be fun and you will enjoy it. Do not try and do it all in one day.

FWIW, I have a 2 meter interconnect and there was no difference in sound between this and my original 1/2 meter. Yes a $10000 does not have these issues but it can if not properly isolation on the "platform it is sitting on.

Good Luck

Jeff

 

[Gordon]

Thanks so much for the recommendations and suggestions guys! I've got a lot to learn end experience. What I found interesting is this: I listened to this table at the sellers house. He had this large 55 gallon looking sub about 5 ft away. He also had a sandbox mounted to the wall in a corner. I heard no pumping in "his room"

Perhaps I should have spent more up front, but at least my son will have something to spin his records on! I'm not going to give up just yet, not until I learn how to correct this.

Thanks again,

Gordon

 

[risabet]

I left you a comment in the Member's Systems area, but will repost here.
http://www.martinloganowners.com/forum/showthread.php?t=350&page=3

Robert, how is the subwoofer hooked up to the system?

Does your room have a concrete ground slab floor?

Line out from the pre to the woofer. The signal to the main amps are hi-passed at 65Hz/6dB per octave.

Solid concrete.

 

[risabet]

Gulp....... hear it....are you sure you don't mean 'feel it' ??

I'm curious, what organ was it ? Living in the Philly area (home to the worlds largest pipe organ) I was wondering if it as the Wanamaker organ.

The Great Organ of Liverpool Cathedral. This organ has a triple blower @ 48.5hp and a wind pressure of up to 35" The 16Hz tone is a note from a 32' Double Open Bass pipe. The 8Hz tone is a resultant note caused by "beating" a 32' pipe with a pipe a fifth away. The 8Hz tone is actually felt as a pressure wave in your internal organs.

 

[User211]

A lot depends on your cartridge and it's frequency response, togther with the roll-off point of your phono stage.

My old Ortofon MC5000 was pretty much unusable with a sub. It's quoted frequency reponse was low, though - a fair amount lower than my Orpheus. And my phono stage doesn't roll off the low frequencies, like many do.

The Orpheus is totally usable - simply because it doesn't go as low. But I still get excursions that are visibly related to the record surface.

Any acoustic feedback will worsen the situation, but no matter how well you isolate the TT, the woofer absolutely will not behave as it does with a digital source.

That's just black pizza blues, to some extent, I guess.

 

[Bernard]

Any acoustic feedback will worsen the situation, but no matter how well you isolate the TT, the woofer absolutely will not behave as it does with a digital source.

Very true, but (and this is straying away from the discussion as a sub was not involved) I was amazed at how much better my digital source sounded when I once happened to put it on my wall-mounted shelf (when I had one).

 

[risabet]

Very true, but (and this is straying away from the discussion as a sub was not involved) I was amazed at how much better my digital source sounded when I once happened to put it on my wall-mounted shelf (when I had one).

True, digital sources are affected by isolation also, usually as a clearer, less, well, digital sound IMO.

 

[Gordon]

Would it be worth the effort to try a Gingko Cloud 11 platform?

Gordon

 

[gordonmenninger]

you may laugh, but working as a nightclub DJ years ago when I was in college, we always had problem with feedback in the DJ booth with our turntables. A quick fix was putting Tennis balls cut in half under each leg of the turntable or I also have seen people use Squash / Raquetball balls (not cut apart) under turntables in clubs with very high bass levels (Cocoon CLub in Frankfurt, Germany - most expensive nightclub sound system install in the world).

good luck!

 

[kach22i]

I wonder if something like this works as well as one might think it would.

Clear Audio
Magix Magnetic Isolation Feet
http://www.gcaudio.com/products/reviews/infomagix.html

Oops, $200 for one?

That would be $600-$800 for one piece of equipment.

 

[spectral]

I wonder if something like this works as well as one might think it would.

Clear Audio
Magix Magnetic Isolation Feet

The main problem with using this and similar devices is that unless the turntable's mass is evenly distributed the tt will be lopsided.

Also, notice that the Clearaudio is marketed as "magnetic", yet Glen Carol says:

The second accomplishment is elimination of the magnetic field.

My question: How did they eliminate the magnetic field? The important issue of magnetism affecting the cartridge has not been answered.

 

[zaphod]

i've seen the tennis ball solution as well, but with a concrete patio slab (18" X 18") on top of the tennis balls.

 

[kach22i]

My question: How did they eliminate the magnetic field?

I think typical shielding is a nickel based alloy called Mu (Mew).

 

[risabet]

I think typical shielding is a nickel based alloy called Mu (Mew).

You can also focus the field using cups of permeable iron that the magnet is placed in, this almost doubles the strength of the magnets.

 

[Peter_Klim]

The main problem with using this and similar devices is that unless the turntable's mass is evenly distributed the tt will be lopsided.

Also, notice that the Clearaudio is marketed as "magnetic", yet Glen Carol says:

The second accomplishment is elimination of the magnetic field.

My question: How did they eliminate the magnetic field? The important issue of magnetism affecting the cartridge has not been answered.

This eases my feeling that I returned the CA 2 weeks ago for a VPI

I was wondering why VPI does create the same floating mechanism in their TTs.

 

[kach22i]

This eases my feeling that I returned the CA 2 weeks ago for a VPI

I was wondering why VPI does create the same floating mechanism in their TTs.

Does?

Or does NOT?

 

[kach22i]

Follow up: 10/23/2009

Spike Sound Will Isolation Feet
http://www.stereotimes.com/acc083109.shtml

at less than $200 for a set of four, provide a (relatively) inexpensive and technologically appealing way of making good sound even better.