Why foam surround?

[Wingman0121 10+ year member]

I see a lot of companies use some type of foam surround on their subs, why not rubber or something else that doesn't crack within a few years of daily playing?

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[ciaonzo 5,000+ posts]

Amen, I can't stand foam surrounds.

There's a small advantage for efficiency but not much. I surmise it's mostly a way to save money for the manufacturer or so they can get something to you for cheapz.

 

[SPLaudio 5,000+ posts]

rubber cracks too. im the opposite i dont like rubber surronds...

 

[whitedragon551 5,000+ posts]

rubber cracks too. im the opposite i dont like rubber surronds...

Eventually, but in the long run its much more durable.

I prefer rubber surrounds to foam and the woven paper surrounds.

 

[RAM_Designs 5,000+ posts]

They figure that you're not going to keep the sub for 5+ years anyways. But I do see many JL subs with good foam surrounds that are 8-10+ years old.

 

[ciaonzo 5,000+ posts]

rubber cracks too. im the opposite i dont like rubber surronds...

Indeed, rubber eventually cracks too, but the difference between how long that takes for the two materials is well in the rubber's favor. Regardless, while the two materials are fresh and new, the rubber will take constant abuse at or near Xmech without failure as long as the glue joints hold up. You simply can't say the same for foam. It rips every time.

 

[SPLaudio 5,000+ posts]

but foam is more eff.

 

[whitedragon551 5,000+ posts]

but foam is more eff.

Id rather have more power with a less efficient rubber surround than less power and a cheap surround.

 

[ciaonzo 5,000+ posts]

Just not enough to justify in my opinion. We're only talking a dB or two here. In fact, you could probably make a thin enough rubber surround to match the efficiency of a normal foam surround of any real durability. I'm sure it's done to address cost these days.

 

[ciaonzo 5,000+ posts]

Although, I do like the idea that Pioneer is using with the layer of mesh or whatever in between two very thin layers of foam. Haven't tried it but it looks decent.

 

[sundownz Pro Seller]

Rubber is also a comparably poor choice in cold climates -- my Russian clients tell me the E8 v.2 surround is like concrete in Moscow this time of year. It's the only rubber surround driver we make now and I may end up changing it for that reason.

A dB or two is a HUGE difference in SPL... you are talking about losing 33-66% of the power put into the driver in the surround at that point. Typically it won't be that dramatic of a loss, though, but enough that it's not going to be desirable unless you simply need extra mass for the design and don't want to put it in the coil.

As far as tearing... if the design limits the driver with the spider or motor first before the surround then there is no problem with mechanical tearing of the surround. It is a balancing act of design.

Most modern foam surrounds will last a LONG time as well since they are treated much better than old ones were. For example... I am not aware of any SI Mag drivers with a rotten surround and some of those are ~8 years old dating back to the v.1 Claw model and are still in usage today... Nick has an original GZ Nuke as well with an intact foam surround -- that thing is OLD.

As for cost... it's not like a rubber surround cost 100 dollars... the price difference is quite small. If a design calls for rubber - I will use it. If it calls for foam - then I will use it. Cost doesn't come into play for me on this matter as it's such a small difference, IMO.

Rubber has it's place, especially when designing a driver with a purposely low Fs, but simply saying "I hate foam - rubber rocks" is a bit short sighted.

 

[on1wheel01 10+ year member]

nice

 

[dbeez 5,000+ posts]

Hammer fist.

 

[ciaonzo 5,000+ posts]

Rubber is also a comparably poor choice in cold climates -- my Russian clients tell me the E8 v.2 surround is like concrete in Moscow this time of year. It's the only rubber surround driver we make now and I may end up changing it for that reason.
A dB or two is a HUGE difference in SPL... you are talking about losing 33-66% of the power put into the driver in the surround at that point. Typically it won't be that dramatic of a loss, though, but enough that it's not going to be desirable unless you simply need extra mass for the design and don't want to put it in the coil.

As far as tearing... if the design limits the driver with the spider or motor first before the surround then there is no problem with mechanical tearing of the surround. It is a balancing act of design.

Most modern foam surrounds will last a LONG time as well since they are treated much better than old ones were. For example... I am not aware of any SI Mag drivers with a rotten surround and some of those are ~8 years old dating back to the v.1 Claw model and are still in usage today... Nick has an original GZ Nuke as well with an intact foam surround -- that thing is OLD.

As for cost... it's not like a rubber surround cost 100 dollars... the price difference is quite small. If a design calls for rubber - I will use it. If it calls for foam - then I will use it. Cost doesn't come into play for me on this matter as it's such a small difference, IMO.

Rubber has it's place, especially when designing a driver with a purposely low Fs, but simply saying "I hate foam - rubber rocks" is a bit short sighted.

I see your point but it depends on what type of rubber. Santoprene is stable from -60C to 135C but it's a polymer and not true rubber. Still it offers better durability. NBR is good from -40C to 108C and is probably the most musical surround to be had. Foam surrounds are usually very thick and become the main factor in the high resonance of most drivers, not desirable in my opinion. All depends on what you want I guess.

 

[SPLaudio 5,000+ posts]

santoprene is perfect for 6.5" and door speakers. i like rubber on coxials and componets do to using them in highly damp area's. for spl foam baby....