spiking vs isolation

madmax

I'm confused on this issue. When do you spike and when do you isolate your speakers???
madmax

faster100

from what i understand, spike with carpet and use rubber stoppers with hardwood floors, what exactly do you mean isolate??

RuSsMaN

Spiking *does* isolate, no?

Cheers,
Russ

faster100

i would think, huh......

madmax

Spiking stops vibration by transfering energy to a less moveable object. Isolation allows it to vibrate as it wants without transfering. (like with rubber feet). ?
madmax

RuSsMaN

Yes, and yes (imo).

'by transfering energy to a less moveable object' you are in essence *isolating*?

Would this statement be true, you would more likely 'spike' your speakers, and 'isolate' your components. How about the rack, spiked? If your speakers are on stands, you would isolate the speaker, spike the stand?

Cheers,
Russ

madmax

It would be but then something about vertical vs horizontal movement comes into play. I'm not even sure what does what. I know you can use spikes with a ball on top and a cap on top of that to isolate horizontally. I'm spouting all this off but I don't really know at all what I'm talking about. Back to the speakers though, I know the SDA's came with rubber feet and spikes. They recommended the feet for applications where you don't want to mark up the floors and the spikes for carpet but that may just be that they know some people care about their wood floors?
madmax

gidrah

Spike to something solid or isolate to something that isn't. Speakers are usually spiked so they don't transfer as much vibes to the floor. Components are usually isolated/absorbed so as to not transfer vibes to other gear or absorb vibrations from each other or your gear. In each case, mass loading is usually recommended.

My rack is kinda flimsy. I choose to isolate. My speakers are light and flimsy. I load, isolate & spike. If I had more room in my rack I'd add weight too.

My speakers are just weighted with sand, absorbed with some polyeurathane biscuits, and spiked with sharpenned bolts connected to the biscuits.

Good luck!

RuSsMaN

Actually, I would still spike on a hardwood/tile floor, but using cones to rest the spikes on.

http://audioadvisor.com/store/productdetail.asp?sku=T/FCUPS

Cheers,
Rooster

Tour2ma

Originally posted by madmax001
Spiking stops vibration by transfering energy to a less moveable object. Isolation allows it to vibrate as it wants without transfering. (like with rubber feet). ?
madmax

This is a good explanation. In either case the object is to not have equipment vibrating. So what you do depends on whether you are talking about equipment that produce vibration (speakers) or does not produce vibration (everything else).

from the SDA SRS Instruction Manual
(Leveling spikes) can be used to stabilize the SDA-SRS on a thickly carpeted floor, and can make a noticeable improvement in the bass response of the system by coupling the system more firmly to the floor through the carpeting.

So isolation of the speaker is not the objective of speaker spikes. Their purpose is to overcome the isolation carpeting can supply. You spike to anchor, or couple, the speaker to the floor beneath the carpet to rid the speaker of cabinet vibration. If you do not, carpet isolates the speaker and in the extreme there is the possibility of the speaker moving. Not like it's going to walk away on you, but it has potential to move very slightly. Remember Doc reporting that his SVS walked a few inches during a movie?

Spiking is really only necessary on deep pile or, if you still live in the 70’s, shag carpet. With the full bottom of the speaker resting on the carpet, even a big boy like an SRS could move when driven hard. Yeah it weighs a lot, but if you spread that weight over its 13x22” bottom, the psi is pretty low. And the friction factor between its smooth wood bottom and the carpet is pretty low as well.

Rubber feet on solid floor, wood, tile or concrete, does the same by supplying a high friction factor without marring the floor’s surface. The rubber feet couple the speaker to the floor by making it immovable relative to the floor.

Actually the non-spike feet on my SRS's are metal, maybe chrome. And while they are on ceramic tile now, when they were on carpet I still used the blunt feet because with them screwed out some, the bottom of the speaker still stayed clear of the carpet. Couldn’t budge them if you tried… coupled.

Only time you’d ever truly work to isolate a speaker is for placement on a bookshelf or other semi-rigid structure you do not want it to become a sounding board.

RuSsMaN

Ahh, coupled and decoupled, two other words not mentioned thus far.

A little Pulp Fiction Quote for ya 'Check out the big brain on Tour!'

Cheers,
Rooster

Tour2ma

I stayed at a Holiday Inn Express last night...

RuSsMaN

WAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAa

madmax

Maybe I fell out of the turnip tree but I'm thinking you guys are saying to spike the speakers? One statement I read was to isolate everything else. For the most part I have been thinking the same thing but recently someone brought up that sometimes if a motorized device such as a DVD, CD or TT is isolated some times the motor will cause a vibration which could otherwise be coupled to a higher mass (and eliminated) with spikes. Why doesn't the simple rules of thumb ever hold up?

RLW was a master at this stuff. Too bad he doesn't visit us much any more. Thanks for the input. Let me know if you think I have the wrong conclusions from this.
madmax

Tour2ma

mm1,

If your speakers are on thick carpet and/or the carpet has a thick pad under it such that the weight of the speaker is resting on its bottom and not the regular leveling pads, yes, I'd spike them.

Of your list of sources, TT’s are by far the most sensitive as they are mechanical devices that work off of vibration. If the drive motor on a TT is vibrating, it has a problem. If it is transferring normal vibration to the platter and album to the point of it being audible, there’s a design issue (my first TT, a Garrard SL-72B was awful). In general, I'd be more concerned with external vibrations getting to tone arm.

There was a thread a while ago where a member was experiencing hellacious distortion when he cranked up the volume and his TT was the source. Turned out that it was due to acoustic feedback because he had the TT on a wall shelf that was collecting sound waves and routing them to the TT via its base. He eliminated the problem by placing a carpet sample on the shelf, under his TT.

As for other sources, I think of digital sources as being relatively immune to mechanical vibration.

BTW, turnips don't grow on trees... the old saying was, "just fell off the turnip truck..."

madmax

Originally posted by Tour2ma

BTW, turnips don't grow on trees... the old saying was, "just fell off the turnip truck..."

Only for someone who knew what he was talking about! As for me, they grow on trees!

madmax

Tour2ma

mantis

Intresting,
I use carpet spikes to send energy into the floor for more of a realism experience.Yes on benefit is the speaker is firmer into place,Lack of movement caused by itself or others.
I have tried both spiked and unspiked with my Lsi15's.I have found that I enjoy the experience of listening better with the spikes in.I un level the speaker from front to back but side to side I keep level.
ALot of subwoofers come with both rubber and carpet spikes.I noticed that using the carpet spikes gives a better experience.The energy transferred into the floor is cool.I dig it.

Tour2ma

So long as the floor cannot move... yes.

When I auditioned the Carver Amazings I bought, the bass sounded like crap... all over the place... boomy, unfocused. Finally figured out it was because it was in a upstairs HT room over the garage. Floor was resonating as a sounding board... not cool.

Put 'em on solid concrete and ceramic tile and .

jtconnell

Okay, so if you're supposed to isolate with spikes or couple or whatever, then the bass braces that used to come with the SRS speakers is for......? I agree with Tour2ma's comments.

My humble opinion always was that you wanted to anchor the speakers somehow so that all of the energy was released in the form of sound as opposed to cabinet movement. As such, I thought the bass brace would be theoretically better since it couples the speakers on a wider plane, thus changing the physics. Since it's on the back side of the speaker the bass brace resists force along the same line that the force is produced (the drivers). A cabinet can still vibrate vertically even though its spiked. I never really thought that spikes were designed to transfer energy into the foor but merely contain the energy within the speakers so that it was properly directed through the drivers.

But, hey, who am I kidding, my SDA SRS's are on rubber feet! Since I have the originals, I can't really use a bass brace either so I'm stuck with spikes when I finally get them to their final resting place in a few months.

Just adding my two cents.

dorokusai

I agree with the masses. I think all speakers benefit from some form of damping, or reinforcement. Bass brace/ Rubbers or spikes will all give subtle differences.

Like Tour said, his issue with flooring, your enviroment really affects your sound. Probably more than you actually realize at first. I spiked my sub, and Dynamatted my speaker mounts, and it made a very noticeable difference overall.

Tour2ma

Originally posted by jtconnell
then the bass braces that used to come with the SRS speakers is for......?

SRS's came with bass braces at one time?

jtconnell

The SDA SRS 1.2 and 1.2 TLs did. I'm not sure about the 2.3 series. It was a 12" piece of all-thread that screwed into the back of the speaker and was secured by a wing nut. The other end was attached to a wall bracket and secured the same way. It's covered in the SDA SRS 1.2 and 1.2 TL owner's manuals.

As I said, since I have the originals, I'm out of luck. You had to remove a plug on the speakers to use the brace. If the plug is gone and you're not using the base, you're compromising the integrity of the cabinent which means you'll lose a lot of bass since the force won't be properly transferred into the passive radiator.:cool:

madmax

Those SDA back braces were supposed to keep the speaker from moving due to bass energy which causes a coloration (spelling?) of the midrange. (according to some polk literature I read some time ago)
madmax