4 inch coils?

[jusBloud 10+ year member]

what's are the advantages/disadvantages of using a sub with 4 inch coils? are they better for playing music daily?

Click to read more...

 

[tc3k101 5,000+ posts]

they will handle more power.

 

[plugitin 5,000+ posts]

more power handling...one of the major advantages

 

[Side Show 10+ year member]

power handleing and cooling i'd say, so yeah it'll handle the power musically for longer than a 2.5 or 3inch voice coil imo...

 

[jusBloud 10+ year member]

no disadvantages? sq, efficiency?

 

[SPLaudio 5,000+ posts]

there are disadvantages such as you need a 9 or 10" spiders because 8" wont allow enough excursion.

some builders will tell you a 3" is the perfect size. personally i have no experience with 4" coils but with todays 3" coils you can throw 10k+ burps and not damage it a bit.

look @ the big sub brands out there today most of the loudest use 3" coils.

 

[jusBloud 10+ year member]

there are disadvantages such as you need a 9 or 10" spiders because 8" wont allow enough excursion.
some builders will tell you a 3" is the perfect size. personally i have no experience with 4" coils but with todays 3" coils you can throw 10k+ burps and not damage it a bit.

look @ the big sub brands out there today most of the loudest use 3" coils.

excursion doesn't mean loud. i don't understand that. it seems like the sub moving the most air with the most cone area should be the loudest. but the subs that have alot of excursion are mostly sq

 

[SPLaudio 5,000+ posts]

^ spl sub BL means more than excursion. my spl sub i am still throwing about 2.250" total excursion....

 

[jusBloud 10+ year member]

^ spl sub BL means more than excursion. my spl sub i am still throwing about 2.250" total excursion....

what is your sub? i love crazy excursion. they usually are louder lower. to me to the ear at least. imo

 

[Kyle_Keating 10+ year member]

excursion doesn't mean loud. i don't understand that. it seems like the sub moving the most air with the most cone area should be the loudest. but the subs that have alot of excursion are mostly sq

You are correct, more excurion does mean louder, the confusing issue is when ports or horn comes into play, but the same principal applies. If we compared a sealed sub to a port, the port might make a lot more SPL but the driver might move a lot less, well its not the driver that's generating the SPL in the ported box, its the driver that is pushing a port at resonance to make the SPL, so we are really comparing the active driver in a sealed box to the port in a ported box and the port will provide more displacement and a lot more excursion. Ports can often move 10" peak to peak and you can do a direct comparison to a driver at that point.

The biggest advantage of a 4" coil is really not the power handling so much but the added BL product. As mentioned, its a full inch larger than 3" so you generally need a larger spider to maintain similar suspension limits. its also heavier so you're going to have to have more BL just to maintain sensitivity, Q will go down if you don't increase the cone size. Generally larger coils implies a more robust driver if you have all the soft parts to go with it.

 

[Kyle_Keating 10+ year member]

^ spl sub BL means more than excursion. my spl sub i am still throwing about 2.250" total excursion....

I don't think you can value BL over displacement, it depends:

If 2.25" is not your max you need either more power or more BL to get to your max. But if that is your excursion max, then you're not going to get anymore SPL from any amount more of BL, no matter what you need more displacement to yield more SPL, even driving a port. Like I said, more BL will get you there with less power, not get you more.

 

[T3mpest 10+ year member]

I don't think you can value BL over displacement, it depends:
If 2.25" is not your max you need either more power or more BL to get to your max. But if that is your excursion max, then you're not going to get anymore SPL from any amount more of BL, no matter what you need more displacement to yield more SPL, even driving a port. Like I said, more BL will get you there with less power, not get you more.

That's essentially the misconception between SPL and diplacement that occurs fairly often. Displacment is still the key factor when it comes to ported boxes, the issue is that without enough motor strength, you'll never get any displacement on the cone near tuning, which means less SPL as you can't excite the port. You can have 45mm of excursion but if the cone only move 5mm near tuning when you put it's recommended power on it, it's not helping you one bit in a ported alignment near those frequencies. As you pointed out the opposite is also true, too much BL without enough xmax will simply send the sub to slamming into it's suspension limits. Sealed however xmax is usually very important although a high BL can allow you to use a very small box, like the tc 5200.

 

[overkill phil 10+ year member]

my hcca's hav 4 inch coils and will blow anybody out of the water: and besides dood voice coil size isnt wat u should go by, try RMS!

 

[assassyn 10+ year member]

On some of the 21" woofers they have 6" coils. I think it has to do with heat

 

[jusBloud 10+ year member]

That's essentially the misconception between SPL and diplacement that occurs fairly often. Displacment is still the key factor when it comes to ported boxes, the issue is that without enough motor strength, you'll never get any displacement on the cone near tuning, which means less SPL as you can't excite the port. You can have 45mm of excursion but if the cone only move 5mm near tuning when you put it's recommended power on it, it's not helping you one bit in a ported alignment near those frequencies. As you pointed out the opposite is also true, too much BL without enough xmax will simply send the sub to slamming into it's suspension limits. Sealed however xmax is usually very important although a high BL can allow you to use a very small box, like the tc 5200.

so the more bl you have the more your sub will move aroud tuning and the louder it will be?