SDA 2B's where to start?

littlewoodboats

PreCd wrote: »

Yep.........definitely from Texas.

Better smile when you say that Pilgrim. :cheesygrin:

inspiredsports

F1nut wrote: »

Absolutely.

+1 to (brass) spikes versus anything else.

audio_alan

F1nut - You said "Absolutely" to TennMan's question of "Do you guys feel that I would get better sound with spikes versus glides if the spikes must be used with discs?"

I thought the entire purpose of spikes is to couple the speaker to the floor, by concentrating the weight to the smallest area possible, and by piercing the carpet or hardwood. However, if you put spikes on disks, that would spread the weight back out to something that resembles the original guides.

IMO, I think there would be negligible difference, at best.

Can you explain why you think spikes on disks would be "absolutely" better to the original guides? Thanks...

littlewoodboats

I thought the purpose of the spikes was to minimize the contact patch between the cabinet and floor. Given use of a proper disk the spike should not know the difference.

F1nut

littlewoodboats wrote: »

I thought the purpose of the spikes was to minimize the contact patch between the cabinet and floor. Given use of a proper disk the spike should not know the difference.

Bingo!

littlewoodboats

F1nut wrote: »

Bingo!

And my parents said a MIT education was wasted :cheesygrin:

TennMan

My monitor 10s are now sitting on stands with plastic glides on the bottom. If I replace the glides on the stands with spikes, will I need to attach the speakers to the stands for the spikes to work properly?

Why would it make a difference if the spikes were brass or some other metal?

heiney9

TennMan wrote: »

If I replace the glides on the stands with spikes, will I need to attach the speakers to the stands for the spikes to work properly?

No, don't physically attach them to the stands. Use something called Blu-tac on the top plate of the stands.

http://www.amazon.com/Bostik-Blu-Tack-Blu-Tack-Re-usable/dp/B0006DPMSG

H9

evhudsons

we don't have that brand here, but they did have another brand just like blutac by the checkout stand at home depot. I use that on my crs+ stands to keep them from sliding off. It sticks extremely well but peels right off when needed. I always wondered if it could be used instead of mortite because it can be smashed tightly, peel off, and seems to stick really tight.

audio_alan

littlewoodboats wrote: »

I thought the purpose of the spikes was to minimize the contact patch between the cabinet and floor. Given use of a proper disk the spike should not know the difference.

Given that statement, then the regular plastic feet should perform equally as well as spikes on disks, when used on hardwood (which was the original question). After-all, neither setup would allow the cabinet to come in contact with the floor...

Schurkey

inspiredsports wrote: »

+1 to (brass) spikes versus anything else.

TennMan wrote: »

Why would it make a difference if the spikes were brass or some other metal?

I'd like to know, too. I think this is a "No Clothes" deal. Brass, steel, aluminum, bronze, titanium, ceramic...if it is strong enough to support the load, the material doesn't matter as long as it isn't compliant. (Rubber or Polyurethane spikes would be worthless even if they could hold the load.)

MY spikes are reworked Grade 8 steel bolts, heads cut off, and the bottom end sharpened on a grinding wheel. Locked into place with jam nuts. They're not audio jewelry, but they are essentially invisible once installed.

audio_alan wrote: »

F1nut - You said "Absolutely" to TennMan's question of "Do you guys feel that I would get better sound with spikes versus glides if the spikes must be used with discs?"

I thought the entire purpose of spikes is to couple the speaker to the floor, by concentrating the weight to the smallest area possible, and by piercing the carpet or hardwood. However, if you put spikes on disks, that would spread the weight back out to something that resembles the original guides.

IMO, I think there would be negligible difference, at best.

Can you explain why you think spikes on disks would be "absolutely" better to the original guides? Thanks...

littlewoodboats wrote: »

I thought the purpose of the spikes was to minimize the contact patch between the cabinet and floor. Given use of a proper disk the spike should not know the difference.

Not exactly. The goal is to couple the speaker cabinets to a solid foundation; this is achieved by reducing the contact patch in order to drive up the unit loading. Reducing the contact patch is the method, not the goal.

If we agree that the spikes would couple very nicely to the protective discs...the spike/disc can almost be treated as a single object. Essentially the same as an hourglass-shaped spike, having X area at the cabinet end, and Y area at the floor end--but with a teeny-tiny middle section.

If you put protective discs on top of carpet, you've just destroyed or tremendously reduced any benefit of spikes that doesn't include height or tilt of the speakers achieved by the installation of spikes. The point (!!!) of spikes is to eliminate the rocking-horse effect of moving parts having mass, mounted to a lever (voice coils and diaphragms mounted at some height above the floor) when that lever (speaker cabinet) isn't coupled to the true floor.

Protective discs on a hardwood floor, I can understand. Protects the wood, but the discs don't have a squishy "gasket" between themselves and the solid floor like they would if there were a layer of carpet (and pad.)

Protective discs on top of carpet would be...pointless.

There is a range of quality to the coupling of cabinet and floor depending on the floor, floor covering, and spikes/discs/glides/etc. Best, I suppose, would be to spike the speakers to a concrete floor. Next would perhaps be to spike to a wood/joist floor, acknowledging that a wood structure is more flexible than concrete. I've heard of guys putting down a marble/granite/concrete slab under the speakers, that would mass-load the wood floor; and the hard, heavy slab would go a long way towards compressing the gasket (carpet, or whatever)--I bet it works very well. Start adding compressible gaskets between the true floor and the speaker cabinet--heavy carpet and pad, carpet with no pad, modern (relatively soft) vinyl tile, and you're back to a de-coupled speaker OR you've poked holes in the gasketing material to get to the true floor.

Schurkey

As usual, took a hundred edits to say what I wanted...and then ran out of edit time.

The last thought I'd express is that if you have a reasonably hard, reasonably rigid floor--you don't need spikes at all. So spikes into protective discs on top of a hardwood floor, or ceramic tile laid on top of concrete (or just plain ol' bare concrete) is fine...but the stock glides (unless they're unreasonably compressible/compliant) would work as well EXCEPT for the height/tilt provisions of the spikes.

audio_alan

Schurkey wrote: »

As usual, took a hundred edits to say what I wanted...and then ran out of edit time.

The last thought I'd express is that if you have a reasonably hard, reasonably rigid floor--you don't need spikes at all. So spikes into protective discs on top of a hardwood floor, or ceramic tile laid on top of concrete (or just plain ol' bare concrete) is fine...but the stock glides (unless they're unreasonably compressible/compliant) would work as well EXCEPT for the height/tilt provisions of the spikes.

That was my thought as well. The stock feet should be able to stabilize the speakers on hardwood floors just as much as spikes on pads/disks...

F1nut

audio_alan wrote: »

Given that statement, then the regular plastic feet should perform equally as well as spikes on disks, when used on hardwood (which was the original question). After-all, neither setup would allow the cabinet to come in contact with the floor...

To start, ever see a plastic spike? Of course not because plastic sucks for the purpose. That purpose is to minimize the contact points between the speaker cabinet and the floor. Metal spikes, even when used with a disc as the disc becomes part of the floor, best accomplish the objective.

audio_alan

F1nut wrote: »

To start, ever see a plastic spike? Of course not because plastic sucks for the purpose. That purpose is to minimize the contact points between the speaker cabinet and the floor. Metal spikes, even when used with a disc as the disc becomes part of the floor, best accomplish the objective.

I agree plastic spikes would be silly. The material wouldn't be strong enough to go down to a point and hold any substantial weight. Metal is the obvious choice.

If the real objective is to minimize the contact of the cabinet from the floor, wouldn't the original plastic feet accomplish that just as well as spikes or spikes on pads? Not touching is not touching, right?

IMO, 90% of the reason spikes work is because people have their speakers on carpet, and they wobble when the bass hits. Spikes pierce through the carpet and pad, and give them a solid foundation - no more wobbling. When it comes to wood floors, that solid foundation is already there (when properly leveled) with feet OR spikes OR spikes on pads.

Perhaps I'm wrong, but Schurkey seems to echo the same sentiments. This has always seemed to be a widely misunderstood and debated topic. For what it's worth, I can say that I believe spikes helped my SDA-SRSs on top of carpet though....

inspiredsports

TennMan wrote: »

. . . why would it make a difference if the spikes were brass or some other metal?

I've used only steel, aluminum and brass, but here are some reasons I like brass the best . . .

Brass has nice workable, durable mid-level hardness on the Mohs Scale (3.5) making it harder than copper and softer than steel. It's a good choice of hardness to get the job done when used as a speaker spike.

It does not rust, does not spark when struck and does not build up a static charge.

It's malleability and acoustic properties have made it the metal of choice for musical instruments for centuries.

Brass also looks good.



To confirm what someone else mentioned earlier, the sonic improvement I experienced after migrating from the factory nylon tacked feet to brass spikes was not subtle.

F1nut

audio_alan wrote: »

If the real objective is to minimize the contact of the cabinet from the floor, wouldn't the original plastic feet accomplish that just as well as spikes or spikes on pads? Not touching is not touching, right?

The difference in surface area contact is quite large between a plastic foot and a the tip of a metal spike.

sda2mike

i have metal spikes...no discs...tile floors....immediate difference!...i dont use discs because the tile is uneven and the spike dont scratch

audio_alan

F1nut wrote: »

The difference in surface area contact is quite large between a plastic foot and a the tip of a metal spike.

Right, but wouldn't the pads that the spikes sit on increase the surface area back out to a similar footprint to the original feet, or maybe even larger? If not, then they are isolating the vibrations to the speaker's cabinet, which is opposite to what spikes straight into wood is doing - coupling the speaker to the floor.

(P.S. Sorry to the original thread starter for somewhat taking this off topic, but this is a mod that you'll want to do... especially if you are on carpet!)

TennMan

inspiredsports wrote: »

I've used only steel, aluminum and brass, but here are some reasons I like brass the best . . .

Brass has nice workable, durable mid-level hardness on the Mohs Scale (3.5) making it harder than copper and softer than steel. It's a good choice of hardness to get the job done when used as a speaker spike.

It does not rust, does not spark when struck and does not build up a static charge.

It's malleability and acoustic properties have made it the metal of choice for musical instruments for centuries.

Brass also looks good.

I agree that brass looks good. Seems like the rest of your list would relate more to fabricating spikes than to how brass spikes would make speakers sound better.

As for the other posts about spikes:

I can see how spikes would be a big help on speakers that sit on carpet for sure. Getting the weight of the speakers on a solid surface so they won't rock would be beneficial. However, I'm still trying to understand the benefits of spikes on hardwood if the weight of the speakers is supported by spikes sitting on discs... compared to the weight of the speakers being supported by adjustable glides made of a hard plastic disc if the diameter is the same for both. The pounds per square inch on the floor would be the same for each one. In both cases there is a round, solid disk against the floor holding up the weight of the speakers. I don't see what the shape of the shaft connecting the disc to the threaded insert in the speaker makes as long as it is solid and is capable of transmitting vibrations to the floor.

I'm not trying to be argumentative at all. I'm trying to grasp the concept of how spikes work on hardwood floors when they are sitting on top of a disc. Thanks for everyone's input. I appreciate it.

pitdogg2

TennMan wrote: »

I'm trying to grasp the concept of how spikes work on hardwood floors when they are sitting on top of a disc. Thanks for everyone's input. I appreciate it.

think of it this way. picture ladies high heel spike shoes. You weigh 200lbs. with a normal shoe that pressure is spread across your whole size 9 shoe with a spike it is concentrated around a very little 1/2" area. best i can do here.

F1nut

You're not trying to transfer vibrations to the floor, just the opposite. Think of the disc as part of the floor with the spike still minimizing contact.

littlewoodboats

audio_alan wrote: »

(P.S. Sorry to the original thread starter for somewhat taking this off topic, but this is a mod that you'll want to do... especially if you are on carpet!)

No worries. As long as we are still talking about speakers we are on topic.

The way I see this the use of the disk depends on the floor. On a hard, smooth surface the disk becomes part of the floor and the spike should not know the difference. As sda2mike points out he does not use the disk as the floor is uneven preventing the disk from making a good mechanical bond with the floor. If the purpose of the spike is to increase psi on the contact patch then placement on any soft surface would be better without the disk.

I would think the disk or no disk decision would be based on the disks ability to sit flush and stable on the surface in question. On a dead level surface disk or no disk should not matter.

If one wanted to be truly anal about the whole thing it could be argued that the base of the disk should be lapped to the floor to make a perfect contact patch. On the other side it could be argued that the extra mechanical joint added by the disk is never a good thing as a perfect contact patch is an unattainable goal. :rolleyes:

sda2mike

i'd be careful with the no-disc approach on a soft surface....2b's weigh 80 lbs, and the spikes will scratch...in my case i can move the speakers if need be and i get no scratch...on a soft uneven surface, use the discs...most if not all, spikes are adjustable..

littlewoodboats

I was thinking about carpeting but you make a valid point. I did not think about something like padded sheet goods (linoleum) where the use of a spike alone would likely damage the surface over time.

littlewoodboats

My RD0-194's arrived and are installed. I can hear a difference already. I am going to like these.

One thing? Should the face of the new tweets sit flush with the baffle or be slightly proud all the way around?

When the Penske truck pulled up in the drive I knew why the FedEx tracking number Polk gave me failed to yield results.

heiney9

Slightly protrude is fine. Wait until they have about 200 hours on them. It takes time for them to break-in and they will sound even better. As per the usual in a few days they might start to sound worse as they break-in but they will come back so be patient and don't freak like some have when in afew days they sound worse.

H9

littlewoodboats

I had read a couple of threads where people had mentioned the changes so will be prepared. Thanks