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What are pro vs con on 3" vs 4" Voice coils?


Hotdog

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bigger is not always better.

it depends on the driver your looking at, to me there are only a few drivers that actually need a 4" coil lvl 6 tsns shw GZ plutonium just to name a few

all of these coils have large windings and are meant to take power. not like mtx 9500s and rf t2s

So are 4" coils also longer then 3" coils? and I did not under stand the not like mtx 9500s and rf t2s part... are you saying that they could have used a 3" coil and stayed in the same power range?

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So are 4" coils also longer then 3" coils? and I did not under stand the not like mtx 9500s and rf t2s part... are you saying that they could have used a 3" coil and stayed in the same power range?

Yes... having a 4" coil just increased the Mms when a 3" coil would have been cheaper and yielded better results and still maintained power rating and durability.

Vehicle: 1997 S10 Blazer 4dr 4X4

Exterior: Rear End Bagged, Black Grill, Lifted 2"

Amplifiers: Rockford Fosgate T8004 & T10001bd

Batteries: 2 Stinger SPV35, Kinetik HC2400

Electrical: Big 3, DC Power 290amp Alternator w/ MLA at 15.5v

Enclosure: 4.2 ft³ @ 33Hz 84sq.in. of port (20sq.in. per cube)

Headunit: Eclipse CD3200 w/ 80G iPod

Mids/Highs: Rockford T152s (a-pillars), Rockford T162s (doors)

Subwoofers: 1 15" Fi BL Fully Loaded

Wire: All 1/0g Kicker Hyperflex

My YouTube Videos

My Fiberglass A-Pillar Build

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My DD1508 T-Line Bandpass Build "Seamless" w/ Acrylic Windows (for '05 TrailBlazer)

My Stealth 8" Fiberglass Build (for '05 TrailBlazer)

My Build For A Friend's '08 Cobalt 15" BL Sealed Off From The Trunk

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So is the power rating mostly based on the coil?

Say you want to run 1000rms to 1 sub.. you can get that with a 3" coil?

and will the sound quality differ any between a 3" and 4" coil on 1000rms?

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Power rating is based on wire gauge, wire material (copper, aluminum), quality, winding width, surface area to dissipate heat, motor cooling, etc... There's alot more to it then just size.

The mtx9500 and RF T2 could have easily gotten away with a 3" coil like I said. The SQ of a driver is dependant on ALOT of things.

Vehicle: 1997 S10 Blazer 4dr 4X4

Exterior: Rear End Bagged, Black Grill, Lifted 2"

Amplifiers: Rockford Fosgate T8004 & T10001bd

Batteries: 2 Stinger SPV35, Kinetik HC2400

Electrical: Big 3, DC Power 290amp Alternator w/ MLA at 15.5v

Enclosure: 4.2 ft³ @ 33Hz 84sq.in. of port (20sq.in. per cube)

Headunit: Eclipse CD3200 w/ 80G iPod

Mids/Highs: Rockford T152s (a-pillars), Rockford T162s (doors)

Subwoofers: 1 15" Fi BL Fully Loaded

Wire: All 1/0g Kicker Hyperflex

My YouTube Videos

My Fiberglass A-Pillar Build

My "Seamless" Looking Box Build

My DD1508 T-Line Bandpass Build "Seamless" w/ Acrylic Windows (for '05 TrailBlazer)

My Stealth 8" Fiberglass Build (for '05 TrailBlazer)

My Build For A Friend's '08 Cobalt 15" BL Sealed Off From The Trunk

My feedback/references...

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the main reason to go with a 4" coil over a 3" is 4" coils are usually used with SPL oriented subs like zdifetz said up there those subs are ment to be burped on 20-40 Kw

where an mtx 9500 and RF with 4" coil can be burped on like 5-6 k tops?

most those subs arnt ment for daily because it takes so much power to get them to there max potential

so thats why you dont see many daily subs with 4" coils

R.I.P!

(Nov-29-2009)

92 explorer

- 4 Atomic Apxx 15s duel .7s - 4rth order bandpass wall -4 powerbass XA-3000D's - 16 8volt batts wired to 16 volts - (9+/9-) runs 0gauge - 152.3 Db @ 29hz

current build

97 chevy lumina4 - 1 Atomic Apx 18 - 6 cube slot port trunk sealed off - 1 powerbass XA-3000D - 2 optima G31s in spare tire18 1 run 1/0

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3" coils typically are much more efficient in SPL application but when a 3" coils limits are reached a 4" coil is often used along with a much larger motor to help accommodate the extra Mms.

Daily drivers such as the SMD runs a 4" coil for daily b/c it is an extremely high power driver made for music on 4kw+ for sustained periods (more than 30seconds)...

Vehicle: 1997 S10 Blazer 4dr 4X4

Exterior: Rear End Bagged, Black Grill, Lifted 2"

Amplifiers: Rockford Fosgate T8004 & T10001bd

Batteries: 2 Stinger SPV35, Kinetik HC2400

Electrical: Big 3, DC Power 290amp Alternator w/ MLA at 15.5v

Enclosure: 4.2 ft³ @ 33Hz 84sq.in. of port (20sq.in. per cube)

Headunit: Eclipse CD3200 w/ 80G iPod

Mids/Highs: Rockford T152s (a-pillars), Rockford T162s (doors)

Subwoofers: 1 15" Fi BL Fully Loaded

Wire: All 1/0g Kicker Hyperflex

My YouTube Videos

My Fiberglass A-Pillar Build

My "Seamless" Looking Box Build

My DD1508 T-Line Bandpass Build "Seamless" w/ Acrylic Windows (for '05 TrailBlazer)

My Stealth 8" Fiberglass Build (for '05 TrailBlazer)

My Build For A Friend's '08 Cobalt 15" BL Sealed Off From The Trunk

My feedback/references...

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Share on other sites

3" coils typically are much more efficient in SPL application but when a 3" coils limits are reached a 4" coil is often used along with a much larger motor to help accommodate the extra Mms.

Daily drivers such as the SMD runs a 4" coil for daily b/c it is an extremely high power driver made for music on 4kw+ for sustained periods (more than 30seconds)...

What are the RMS Limits on a 3" coil and a 4" coil? and how much does the motor play in determining the limits of each coil?

Don't mean to ask so many questions but it will be great for more people to read when looking for subs and how to determine how to make choices.

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So many aspects between the 2 sizes

the majority is right cooling, but you can make a cooler running coil with other features, like the Fi and DD cooling techniques by machining the pole pieces, and top plates to allow extra air cooling, or aluminum heat sinks

on coils the majority of cooling is winding area and the former helps A-LOT as well, when its aluminum, titanium or stainless, it helps suck the heat from the coil wire, and disperses the heat to the dome/cone, also the heat radiates to the top plate, and pole piece as well.

The disadvantages to 4" coils is the weight of the coil, how it effects the parameters of the speaker. Typical aluminum coil is about 3 times what a 3" coil is. And when you go to copper, well, a copper 4" coil will weight about 6-10 times what a typical 4" coil weighs

This picture here,

DSCN2413.jpg

shows a HX2 Power 4" coil far right, its copper

Middle is a TRF coil, just a 4 layer flat aluminum on aluminum former

and a bi-filar 4" on the left ( 2 wires ran down the former when making the coil )

The HX2 coil is copper round wire, with 2" of winding width/height, while the TRF is 2.3" , and the 3rd on the left is 2.8" ww

The weight of that copper coil weighs A LOT, so it brings the efficiency of the woofer down a lot

DSCN2412.jpg

This just shows some 4" coils next to 3" coils

sundown.jpg
I have a ritual called "terminator". I crouch in the shower in the "naked terminator" pose. With eyes closed I crouch for a minute and visualize either Arnie or the guy from the 2nd movie. I then start to hum the T2 theme. Slowly I rise to a standing position and open my eyes. It helps me get through my day. The only problem is if the shower curtain sticks to my terminator leg. It sorta ruins the fantasy.
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forgot to mention, usually a 4" coil needs more power to get it to the same output as a 3" coil

also besides power handling being based on cooling, and coil size, actually suspension plays a big part in the mechanical part of power handling

if you have a cone with a soft suspension, and a single spider, yet a strong motor/coil, and when you hit that woofer with some real power, that coil will want to shoot right out of that motor, and sometimes literally rip apart

thats why these woofers that do handle tons of power, usually have very stiff suspensions, multiple spiders, etc etc

sundown.jpg
I have a ritual called "terminator". I crouch in the shower in the "naked terminator" pose. With eyes closed I crouch for a minute and visualize either Arnie or the guy from the 2nd movie. I then start to hum the T2 theme. Slowly I rise to a standing position and open my eyes. It helps me get through my day. The only problem is if the shower curtain sticks to my terminator leg. It sorta ruins the fantasy.
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hey bumpin do they make 3.5" coils?

R.I.P!

(Nov-29-2009)

92 explorer

- 4 Atomic Apxx 15s duel .7s - 4rth order bandpass wall -4 powerbass XA-3000D's - 16 8volt batts wired to 16 volts - (9+/9-) runs 0gauge - 152.3 Db @ 29hz

current build

97 chevy lumina4 - 1 Atomic Apx 18 - 6 cube slot port trunk sealed off - 1 powerbass XA-3000D - 2 optima G31s in spare tire18 1 run 1/0

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