dB estimate

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walty220

Copper - Posts: 75

Joined: January 15, 2004

Location: United States

Posted: February 02, 2004 at 9:00 PM / IP Logged

ive gotta 12" HE2 Fosgate with a 401s Fosgate amp. Its in a sealed box, pushin 400 watts RMS, any body have any clue what kind of spl that might have, even though its punch series?? just guess at my dB, thanks

jpranwez

Member - Posts: 33

Joined: January 12, 2004

Location: United Kingdom

Posted: February 02, 2004 at 9:41 PM / IP Logged

Have it measured. Somebody more experience than I might be able to tell you, but they'll want to know what kind of car and probably some other stuff.

walty220

Copper - Posts: 75

Joined: January 15, 2004

Location: United States

Posted: February 02, 2004 at 9:57 PM / IP Logged

1983 cutlass supreme,its in my trunk

Teamrf

Gold - Posts: 1,031

Joined: January 13, 2004

Location: United States

Posted: February 02, 2004 at 10:23 PM / IP Logged

Well it's hard to estimate db's...you have to take in consideration about your voltage...box size...ports or no....trunk size...insulation...it's a lot of things you have to think about before you can estimate dbs it's almost impossible to guess it. Because to go from 100 dbs to 103 dbs you have to double something to get there. So without having it metered you are basically clueless.

~The Rookie~

Rookie of the year that is...

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Julian59

Member - Posts: 24

Joined: January 31, 2004

Location: United States

Posted: February 03, 2004 at 1:13 AM / IP Logged

Below 98db for sure. the speakers are not efficient enough.

Julian59

Be Smart Never Assume

Improvise Adapt and Over Come

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Installer/Technician 20 years

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Joined: November 01, 2003

Location: Alberta, Canada

Posted: February 03, 2004 at 1:04 PM / IP Logged

I would bet that he is above 115 db, maybe even closer to 125db. Most single sub systems are certainly capable of this, but like stated above, have it metered. There are a lot of factors that add to spl levels, teamrf mentioned some above, another is cabin gain, and it will have a lot to do with your reading.

Top Secret, I can tell you but then my wife will kill me.

Julian59

Member - Posts: 24

Joined: January 31, 2004

Location: United States

Posted: February 03, 2004 at 1:56 PM / IP Logged

walty220

Ok here are the specs, no guessing just the facts! The Rockford Fosgate HE2 (RFD3212) it's efficientcy is only 87db@ 1watt / 1meter Power Handling (RMS) is 400 Max is at 800 at 4 ohms. If you max this out at 800 watts you'll only maybe get an increase of 4 db. The numbers don't lie, always do the math before you buy. Sorry if this isn't what you want to hear.

Julian59

Be Smart Never Assume

Improvise Adapt and Over Come

=============================

Installer/Technician 20 years

forbidden

Platinum - Posts: 5,352

Joined: November 01, 2003

Location: Alberta, Canada

Posted: February 03, 2004 at 2:20 PM / IP Logged

Julian, not to knock you at all but do a little more research into the math involved. If It generally assumed that a doubling of power is a gain of 3db, then we need to check the math. If it is in a ported enclosure, then add 3db as well, add cabin gain, this is pressurizing a small airspace, not a big room. A factory stereo with no sub can play above 100db. I stand firm that the system should play above 115db and probably close to 125db. Please let me know what you think on this if you have or I have any misconceptions.

1 watt = 87db

2watt = 90db

4watt = 93db

8watt = 96db

16watt = 99db

32watt = 102db

64watt = 105db

128watt = 108db

256watt = 111db

512watt = 114db

Top Secret, I can tell you but then my wife will kill me.

Julian59

Member - Posts: 24

Joined: January 31, 2004

Location: United States

Posted: February 03, 2004 at 3:29 PM / IP Logged

Forbidden

Thank you for the heads up, but I'm sorry to say that's not right. The speaker in question is rated at 87db @ 1 watt / 1 meter. There is no way this speaker will ever come close to those figures you have. It doesn't matter what type of enclosure this is in. Rule of thumb is in order to gain 3db is to increase the power no lell then 100 watts. You will gain SPL but no more then 3 dbs +- .05. I hav't read the MECP manual in about 10 years. but I do know that's this is in there. Check it out. The key word here is DBs.

Thx

Julian59

Be Smart Never Assume

Improvise Adapt and Over Come

=============================

Installer/Technician 20 years

jpranwez

Member - Posts: 33

Joined: January 12, 2004

Location: United Kingdom

Posted: February 03, 2004 at 4:34 PM / IP Logged

Exactly what does the efficiency rating mean. I was told it's the sound level that a sub is most efficient but that sounded odd.

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