Dual Pockets

Posted in Travel-01-02 by admin on November 30, 2005 No Comments yet

Dual Pockets
Dual Pockets
i have 2 12"solobaric l7 and the only good sound i hear is the insode bass?

i have a big box that came with the kickers (dual box)someone told me there might be too much air space or too tight!and i have a ma audio 2000 watt amp its sounds ok but my cousin installed the music . i wanted some advice before ipay out of pocket what could be wrong? my box is _o___o___ (somewhat like that)

It's hard to know exactly what the problem you are facing without being there. Still, in regard to the actual system, there are several things to consider here:

the 12L7's, though having specs for sealed enclosures, really do well in a ported enclosure of about 2.96 cubic feet including the displacement with the vent. I cant recall the exact vent size... something like 2.5 inches wide by 10? inches long, by 17? inches deep... I used to build them all the time and it worked well in many applications. Naturally, its not the only vented size that works well, just one of many that have been done and one that worked exceptionally well in my experience. If the box is sealed, you may still get a good response but it wont be as loud and "boomy" as what a vented/ported box would be. In either case, the box must be air tight (save the opening of the port).

You have 2 12L7's... what ohm load are you running to the amp? If it's an 8 ohm load, then you arent getting the power you should. If it's 2 ohms or lower, you may be getting too much out of the amp and could damage the amp. You noted that its an MA Audio brand amp... what model amp is it? This would give me some more specific info on the amp. I'm presuming the amp is wired correctly but if not (as indicated above), many other problems can occur. However, capacitors are not necessarily needed. They may help but its not mandatory. Loose grounds can definately cause problems but really, you would have a lot more issues than just it only sounding good inside. If the amp was wired poorly, you may have other intermittent, if not constant problems such as the amp going into thermal shutdown, become very hot, fuses blowing, or strange sounds coming from the subs.

In regard to amps too, many ppl think that the max rating on the amp is what the amp will continuously put out but that is far from the case. I dont want to ridicule your choice of amp but to be honest, MA Audio (Mobile Authority Audio is what they were called in the early 90's) is not that good of a company to begin with. The quality of their components is not comparable to better brands such as JL Audio, Kicker, Phoenix Gold, or Boston Acoustics, to name a few. At best, that amp is probably doing 1000watts rms, if that much. That means that each sub, **at best**, is getting 500watts, but most likely considerably less. Unfortunately for your system, the 12L7 takes more power than that, usually as much as 700 to 900watts if not more (I've pushed them with as much as 900 watts per speaker without problem). In my work truck, I have one 10L7 seeing 725watts RMS all day and does really well (sealed downfire box). My wife has 2 12L7's in her 04 Impala with a Memphis Car Audio ST-1000D pushing both at 1 ohm. That's a little more than 1200watts going to them both, if not more as Memphis is known to underrate the RMS rating of the amp, and it's still not enough. I've also run 1000watts RMS to EACH VOICE COIL of 4 15L7's in vented enclosures, (2000watts rms per speaker, amp gains were matched). The system slammed but could have held more even.

One thing important to note is that Kicker 12L7's only need about .85 to 1.0 cubic feet for a really good sealed enclosure, (maybe even as small as .70 with high, high power going to them; no bigger than 1.25 before the output starts to decline in quality). If you have a really big box and its not ported then it's quite likely that you have the wrong size box. Having too much air will drastically impair the performance of a sub.

There are more things also that you could look at such as internal acoustics, the use of dynamat or other sound deadener, adequate power wire going to the amp coming from the amp to the woofer (12 guage is adequate for 95% of the installs out there. I dont recommend smaller), etc. If you are having rattling that's heard outside, make sure whatever bolts or screws or panels that you can physically reach with a rachet or screwdriver are tight. You can use some form of sound deadener on the underside of the trunk too, that may help.

I could probably add more to this but I think you have enough here to start with. I dont know what your experience with box design/building is so to lend a hand a bit, I'm going to put the instructions for calculating the air space of a rectangle/square box. To calculate the air space, you...

1) first want to know what size material the box is made out of. Most are made out of 3/4 inch material, typically medium density fiberboard (MDF).

2) Next, take measurements of the box: the length, the width, and the height (or depth depending on how you want to look at it).

3) You have to account for the material the box is made out of; if not, you will over-calculate your volume. So, if it's made out of 3/4 inch material, you have to double it for each measurement (3/4 inch thick wall on one side + 3/4 inch thick wall on the other side = 1 1/2 inches, or 1.5 inches). If it's 5/8 inch (another common thickness, do the same thing (5/8 = .625, doubled = 1 1/4 or 1.25)

4) Subtract the doubled amount (1.5 in the example) from each measurement and that will give you your internal dimensions.

5) Multiply the internal dimensions together, that will give you the total cubic inches.

6) Divide that number by 1728 (or divide by 12 three times, same thing) and that will give you the internal volume. The result will be a reasonably close approximate as you arent accounting for speaker displacement or the internal divider, if present. They will be very accurate though, no more than a few hundreds of a cubic foot off (which isnt enough to be noticable by anyone).

Good Luck!

~G~

New Omron HJ 112 GOsmart Dual Axis Pocket Pedometer New Omron HJ 112 GOsmart Dual Axis Pocket Pedometer Paypal 3 Bids US $17.50 47m
Dual Time Display Case Pocket Watch with Chain RARE Dual Time Display Case Pocket Watch with Chain RARE Paypal 0 Bid US $1.48 4h 40m
Dual Time Nostalgic Tone Fire Fighter Mens Pocket Watch Dual Time Nostalgic Tone Fire Fighter Mens Pocket Watch Paypal US $8.97 5h 8m
Black Leather Dual Pockets $ COIN Holder Wallet Purse S Black Leather Dual Pockets $ COIN Holder Wallet Purse S Paypal 0 Bid US $3.78 5h 10m
Free SH 49cc DUAL Shock Brake Mini Pocket ATV Quad YLW Free SH 49cc DUAL Shock Brake Mini Pocket ATV Quad YLW Paypal US $346.50 5h 17m
Unique Classical DRAGON Pocket Watch Dual tone Unique Classical DRAGON Pocket Watch Dual tone Paypal US $2.98 5h 27m
Bronze Rome Mechanical Pocket Watch Dual Open Designer Bronze Rome Mechanical Pocket Watch Dual Open Designer Paypal 0 Bid US $.01 5h 28m
Dual Time Roman Numeral Mens Pocket Watch Chain Dual Time Roman Numeral Mens Pocket Watch Chain Paypal US $8.53 5h 50m
Womens Leather Coin Purse Wallet Dual Pocket New Brown Womens Leather Coin Purse Wallet Dual Pocket New Brown Paypal US $7.50 5h 58m
Free SH 49cc DUAL Shock Brake Mini Pocket ATV Quad RED Free SH 49cc DUAL Shock Brake Mini Pocket ATV Quad RED Paypal US $365.75 6h 35m
1 New Pocket Rocket Bike with Dual Exhaust Disk Brake 1 New Pocket Rocket Bike with Dual Exhaust Disk Brake Paypal 0 Bid US $119.00 6h 58m
1 New Mini Pocket Dirt Bike w Dual Exhaust Disk Brakes 1 New Mini Pocket Dirt Bike w Dual Exhaust Disk Brakes Paypal 0 Bid US $139.00 6h 58m
Carrying Sleeve Dual Pocket Case for Irex DR 800 SG Carrying Sleeve Dual Pocket Case for Irex DR 800 SG Paypal US $8.99 7h 7m
Soft Portable Arm Band Dual Pocket Design Pouch Bag Soft Portable Arm Band Dual Pocket Design Pouch Bag Paypal US $7.73 8h 31m
Carry Soft Sleeve Dual Pocket Case for Irex DR 800 SG Carry Soft Sleeve Dual Pocket Case for Irex DR 800 SG Paypal US $8.99 9h 14m
Dual Time Roman Numeral Mens Pocket Watch Chain Dual Time Roman Numeral Mens Pocket Watch Chain Paypal 0 Bid US $.91 12h 15m
New Soft Apple Green Mobile Phone Pouch Dual Pockets New Soft Apple Green Mobile Phone Pouch Dual Pockets Paypal 0 Bid US $1.48 15h 44m
CLASSIC MECHANICAL SILVER POCKET WACTH W DUAL SIDES 183 CLASSIC MECHANICAL SILVER POCKET WACTH W DUAL SIDES 183 Paypal US $13.46 15h 51m
Omron Pocket Pedometer Gosmart Dual Axis New Omron Pocket Pedometer Gosmart Dual Axis New Paypal US $53.97 20h 31m
Dual Blade Lockback Multifunction Pocket Knife 20295BL Dual Blade Lockback Multifunction Pocket Knife 20295BL Paypal 0 Bid US $9.99 23h 51m
cool men lady sport LED dual pocket wrist watch black cool men lady sport LED dual pocket wrist watch black Paypal 0 Bid US $.01 23h 54m
LARGE Leather DUAL POCKET $$ COIN Holder Wallet Purse LARGE Leather DUAL POCKET $$ COIN Holder Wallet Purse Paypal 0 Bid US $4.99 1d 1h
Womens Leather Coin Purse Wallet Dual Pocket New Purple Womens Leather Coin Purse Wallet Dual Pocket New Purple Paypal US $6.75 1d 1h 38m
Neoprene Dual Pocket Mobile Arm Bag w Velcro Strap Neoprene Dual Pocket Mobile Arm Bag w Velcro Strap Paypal US $7.73 1d 1h 38m
Womens Leather Coin Purse Wallet Dual Pocket New Red Womens Leather Coin Purse Wallet Dual Pocket New Red Paypal US $6.75 1d 1h 43m
VINTAGE IMPERIAL BRAND DUAL BLADE POCKET KNIFE VINTAGE IMPERIAL BRAND DUAL BLADE POCKET KNIFE Paypal 0 Bid US $4.99 1d 3h 42m
Womens Leather Coin Purse Wallet Dual Pocket New Pink Womens Leather Coin Purse Wallet Dual Pocket New Pink Paypal US $6.99 1d 6h 17m
Dark Knight BAT Man Pocket Knife Folder Dual Blades Dark Knight BAT Man Pocket Knife Folder Dual Blades Paypal 0 Bid US $9.99 1d 7h 19m
Beautiful Lonchamp dual pocket messenger tote bag purse Beautiful Lonchamp dual pocket messenger tote bag purse Paypal US $100.00 1d 8h
CLASSIC MECHANICAL GOLDEN POCKET WACTH W DUAL SIDES 182 CLASSIC MECHANICAL GOLDEN POCKET WACTH W DUAL SIDES 182 Paypal US $13.46 1d 15h 45m
BRAND NEW RARE GENTS DUAL TIME DISPLAY POCKET WATCH BRAND NEW RARE GENTS DUAL TIME DISPLAY POCKET WATCH Paypal 0 Bid US $22.44 1d 22h 2m
White Dual Pocket Handbag White Dual Pocket Handbag Paypal 0 Bid US $1.48 2d 1h 1m
Dual Blade Lockback Multifunction Pocket Knife 20295BK Dual Blade Lockback Multifunction Pocket Knife 20295BK Paypal 0 Bid US $9.99 2d 7h 55m
M92S PISTOL SAFETY LOCK DUAL TORCH PIEZO POCKET LIGHTER M92S PISTOL SAFETY LOCK DUAL TORCH PIEZO POCKET LIGHTER Paypal US $2.22 2d 11h 9m
cool men lady sport LED dual pocket wrist watch white cool men lady sport LED dual pocket wrist watch white Paypal 0 Bid US $.01 2d 17h 58m
DUAL HEAD POCKET TIRE GAUGE DUAL HEAD POCKET TIRE GAUGE Paypal 0 Bid US $.99 2d 21h 49m
Smartphone Windows Mobile Pocket PC 60 PDA DUAL SIM NR Smartphone Windows Mobile Pocket PC 60 PDA DUAL SIM NR Paypal 4 Bids US $5.51 2d 23h 38m
Dragon Dual Blade Multifunction Pocket Fantasy Knife Dragon Dual Blade Multifunction Pocket Fantasy Knife Paypal 0 Bid US $9.99 3d 57m
Vintage Camco 703 Advertising Pocket Knife Dual Blade Vintage Camco 703 Advertising Pocket Knife Dual Blade Paypal 0 Bid US $7.00 3d 3h 8m
Vintage Autopoint Mother Pearl Pocket Knife Dual Blade Vintage Autopoint Mother Pearl Pocket Knife Dual Blade Paypal 1 Bid US $7.00 3d 3h 14m
Vintage Bothham Japan Camo Old Pocket Knife Dual Blade Vintage Bothham Japan Camo Old Pocket Knife Dual Blade Paypal 0 Bid US $7.00 3d 3h 17m
Vintage Mini Bone Handle Old Pocket Knife Dual Blade Vintage Mini Bone Handle Old Pocket Knife Dual Blade Paypal 1 Bid US $5.00 3d 3h 26m
Vintage Mklein Sons Chicago dual blade Pocket Knife Vintage Mklein Sons Chicago dual blade Pocket Knife Paypal 0 Bid US $7.77 3d 4h 28m
Omron Go Smart PC Version Dual Axis Pocket Pedometer Omron Go Smart PC Version Dual Axis Pocket Pedometer Paypal US $33.00 3d 5h 2m