Granite Bases

[Gsal]

I know that this subject has been discussed ad nauseam but please bear with me as I believe my situation involves a slight twist.

I own a pair of Quatro CT Wood's and my listening room is above my garage on a "floating floor". The speakers were installed by my dealer and the bass equalization painstakingly set using a calibrated microphone, Vandertones and additional frequency sweep tests. I am reluctant to make any changes as the low end has been tuned to my room as it is. Nonetheless, I would like to address the vibrations and speaker movement that I am certain are a result of the wobbly floor and thereby reduce IM distortion.

In the past I used granite bases under my Treos but the larger footprint of the Quatros precluded my using the granite I had on hand.

I guess the question is whether or not placing granite under the Quatros or some other isolation material ( I use elsewhere and am fond of the EVP Equipment Vibration Protectors created by Norm Varney at A/V Room Services) will alter the low end response and require re-calibration of the equalization? My thinking is that since the Quatros were dialed in without anything between them and my floor perhaps there was a naturally occurring bass hump (s) at some floor resonance frequency that was detected and compensated for by my installer when he performed the equalization. Simply isolating the speakers from the floor after the fact could then result in a bass suck out at that (those) frequencies.

I am really not up for recalibration of the low end but if the improvement is warranted then I may have to consider it.

RV is you are available to comment I'd really appreciate it.

Thanks in advance to all.

[ursus13]

I was preparing to compose a very similar question. Thanks for articulating it so well. Interested to hear the response(s.)

[GdnrBob]

I'll go out on a limb here...

That the newest models like the Kento have integrated solid bases, I think all the named models will benefit from using the granite plinths. This might require resetting the tilt (as they sit higher), as well as re equalizing the bass. FWIW, I wouldn't expect a huge change in bass, but, since every room is different, I wouldn't swear to it.

I put my Treo's on some marble bases and it really seemed to clear up some 'muddiness'. As I use Sub 3's, the bass was little affected. So, YMMV.

Bob

[Holmz]

6 hours ago, GdnrBob said:

I'll go out on a limb here...

…

Bob

And I’ll swing from the another limb… 😄

I am assuming that the movement will alter the phase relative to the amplitude of the movement and the wavelength.
At 100 Hz the wave length is about 10’ (~11 probably, but I use 1000’/sec to keep the numbers easy in my head)
Hence the only affect to the low notes would be moving the speaker upwards, and changing it mode interaction with the room.

10KHz is about 1” wavelength so things get a bit more constructive and destructive and a 1/4” movement of the chassis is 90 degrees and if it bouncing off of a wall, the one gets a two-for-one.

If one lifted them up for a 4” granite plate then the floor-ceiling, and other modes that are not purely horizontal,  would be getting about a 12 degrees phase shift at 100 Hz.
pretty much 36 degrees/foot with a 10 foot wavelength and 4” is a third of a foot… if one was near a null then that can be a huge bump up, but near a peak it is almost no change in amplitude downwards.
(And we should not really be signal boosting much, and most taking away peaks.)

I would certainly take a picture of the pot settings, but I would not stress much about moving them.

 

And I am musing… does Tarzan listens to the Cowboy Junkies song, “Sweet Sweet Jane”?

[ctsooner]

It will depend on how much you want and are able to do IRT set up. They are still sounding great from the tenor of your post.  IF you want them to sound better, using granite bases like so many of we Quatro owners do would most probably help (make sure to use the Vandershoes).  Yes, you will need to change the tilt a bit. I have no clue about retuning the bass.  Randal may be onto something,  but as you all know, that's WAY above my pay grade, lol.  Great post

[Gsal]

Thanks to all for your thoughtful comments.

Very interesting data Holmz. Much appreciated for that angle (no pun intended) of thought. I was only thinking of the tympanic membrane effects of the floor. Hmm.

I have an email into Norm Varney and await his comments as I am leaning toward his EVPs. Of course, they would only serve to decouple the speakers from the floor. A granite base would as I understand it effect a quite different result. I know RV has some definite opinions in this regard. Maybe I need both a granite base and the EVPs?

The plot thickens...

PS. Both RV and Norm are at Axpona so this discussion may be in limbo for a while. I'd like to get the two of them in a room. 🙂

[Holmz]

On 4/12/2023 at 6:28 PM, Gsal said:

… this discussion may be in limbo for a while.

There are a lot of limbs and limbos.

If the speakers don’t move at all then they do not need adjustment at all.
If they move across the room, they may need a lot.
If they move a small amount then I would assume that they would need a small adjustment.

and in a rectangular room of they move from the left wall to the right wall, then the modes in the room are defined by the room dimensions, so if they move symmetrically and the listening position flips over to the symmetric mirror image, then I would suspect that the settings also stay the same.

[Stringreen]

I have my 5A's on their spikes which are on brass protectors which are on travertine tile which are cemented to the bedrock of the house.  I would suspect I don't need the granite 

[ctsooner]

no granite needed String, lol.  I would use Richard's inexpensive Vandershoes instead of the brass (the special felt makes a difference for the better).  Worth a try as many of us who use granite have gone that route and loved it.  Just a thought that's not expensive. 

[GdnrBob]

On 4/18/2023 at 2:15 PM, ctsooner said:

Worth a try as many of us who use granite have gone that route and loved it.  Just a thought that's not expensive. 

As I have posted, try to find a granite machine block on Amazon. It takes a bit of searching, but if you can find one, it is well worth the cost (vs buying from a stone company).

B

[ctsooner]

It's easier and cheaper to just get a cut off piece at a counter shop and have them chamfer the edges and cut to size.  I paid hardly anything for them.  I think I was only charged for the machine time to finish the piece.  

[BKDad]

34 minutes ago, ctsooner said:

It's easier and cheaper to just get a cut off piece at a counter shop and have them chamfer the edges and cut to size.  I paid hardly anything for them.  I think I was only charged for the machine time to finish the piece.  

Not to mention the shipping!!!

Everybody around this forum gets all gooey eyed about their loudspeaker finish.  And, why shouldn't they?  Here's a chance to accessorize your loudspeaker set-up in a wide range of colors.  Why aren't more photos of the bases posted here?

Now, back to the workbench...

[GdnrBob]

Free shipping on Amazon Prime.

[BKDad]

Welllll, the closest size that Amazon offers this minute for use under Quatros cost just under $200 each.  I may have missed an alternative, though, because I didn't perform a thorough search.

As Pete described, I was able to get custom bases fabricated locally.  The difference is that I got two for that price instead of one.  Plus, it's the color my wife chose.

But, whatever works!

[Holmz]

12 hours ago, ctsooner said:

It's easier and cheaper to just get a cut off piece at a counter shop and have them chamfer the edges and cut to size.  I paid hardly anything for them.  I think I was only charged for the machine time to finish the piece.  

^Agree^

A machinist piece of granite is called a surface plate, and used for precision measurements.
If one has dial indicators, and similar stuff, then it is a bit of an important thing in a machine shop. 

[ctsooner]

I used them in the shop on the aircraft carrier back in the 80's as we needed that precision, but on a carrier (on the water floating) it was a moot point.  lol.  I've seen them in plenty of labs. Hey, it's your money and it that's what you want to spend the extra couple of hundred on, go for it. For speaker purposes, a flat piece of granite works great in addition to what BK posted about color choice, edge finish choice and size.  It's all good either way.  I went back and looked at the check and it only cost me about $80 total (as I said, they were black with gold flake that perfectly matched my Audi Havana Black (copper flake like the stones).  It's a stunning look for sure.  Again, it's all good, just do it with your Vandershoes, lol.

 

[GdnrBob]

Funny, but when I looked to buy the granite from a stone mason, the price was considerably higher than the $160 I paid.

Bob

[ctsooner]

Bob, it's probably the Long Island special tax 😉

[Stringreen]

On 4/18/2023 at 11:15 AM, ctsooner said:

no granite needed String, lol.  I would use Richard's inexpensive Vandershoes instead of the brass (the special felt makes a difference for the better).  Worth a try as many of us who use granite have gone that route and loved it.  Just a thought that's not expensive. 

..just a word of thanks....you're absolutely right.  The new shoes that I just got under my 5A's make a very positive difference.....pitch definition, separation of voices, air, etc.....all the right stuff.  

[Holmz]

10 minutes ago, Stringreen said:

The new shoes that I just got…

Imelda 

[ctsooner]

I have an Imelda story involving my time in the Philippines that I can’t share here lol.  Thanks Randall. Hehe

[Holmz]

15 hours ago, ctsooner said:

I have an Imelda story involving my time in the Philippines that I can’t share here lol.  Thanks Randall. Hehe

Well, maybe I’ll call… 😁

Then I’ll tell you about the Nordstrom shoe night sale.

[ctsooner]

My ex GF there was in her cabinet and unwilling to move to the US to 'live' with me.  I didn't promise marriage as I never wanted to get married (done it twice and finally happy).  Stunning women with the 50/50 mix of Spanish blood with Chinese on mom's side.  Tall and a model with an MBA.  The Admiral set me up with her and we 'dated' for 3 years.  I'm still in touch with her and her youngest sister as they ended up moving to the US years after I last saw her.  Oh, she too had a fun closet of shoes in her Oolongapo house.  Thanks for those memories Randall 😉. hehe

[Holmz]

I picked up an old Dame Edna LP at a used shop in Perth a couple of weeks ago.
Barry Humphries just passed away.

 

[ctsooner]

Cool. I had a good friend in Perth too and we are still in touch. Sorry, you got me back to my ship steaming days Randall. Loved  Perth   Are there many high end shops there?  Record stores?