Hi everyone,
I currently own a '92 Towncar, and as of right now I'm trying to get some real bass to even out my stereo system. It's a long history, but the short version is I bought a Rockford Fosgate amp that pushed 75w rms x 2 @ 4ohms and 2 R.F. 12" Subs that were 150w RMS each. Needless to say, I wasn't satisfied, so I got another amp - a Profile Clarus CL600, which pushed 150w RMS x 2 @ 4 ohms. My bass got twice as loud and I was happy. Recently, I've decided to upgrade to a Audiobahn A1500HCT, which being a monoblock amp, does 500w RMS x 1 @ 4 ohms, 1000w RMS x 1 @ 2ohms, and 2000w RMS x 1 @ 1ohm!. I decided to take a chance and get top of the line Mobile Authority 12" Subs(150 oz. magnets), each rated w/ 4 ohm impedance and 500w RMS power cosumption. I have them wired correctly so my amp sees a 2 ohm load, so they should be getting 1000w RMS right? My problem is that when I have these hooked up, with all setting on amp and headunit dialed in, they're not even quite as loud as my 150w Rockfords - how can this be? I know the amp is drawing power because everytime it hits it pulls so much power that all my light in my Towncar dim a significant amount. The amp is a brand new 2003 model with flames, straight from Audiobahn, I used to have a A1500HCX, but that one was defective. I'm using 12 gauge wire with the speaker connection inside the box, I've resealed the inside of the box with liquid nails, and as far as I know have a real quality setup.
Does anyone have any ideas about what could be wrong (w/ my electrical system or setup - whatever)? I realize that Mobile Authority may make crap subs (I'm going to get Audiobahn soon - look at my "Need Educated Advice Topic"), but being fully powered they should atleast hit harder than my old low-powered R.Fs. Sorry bout length of post, had a bunch of s**t to say.
Replies (8)
ttocs on 06/11/2003 12:23:02
we might be able to help.
Did you upgrade the wiring going to that shiney new amp with the flames? If not, what size pwr wires are you running? You should probably have a minimum of 4 awg for an amp that size.
Another option, did you put the shiney new subs in the same box? If so you might check to see if the airspace requirements on the two are similar, if not the same.
I'll check back shortly..
Swez on 06/12/2003 09:00:00
Yes, I agree with ttocks... power management issues and the right sub enclosure for these MA subs are probably your main issues.
That amp pulls a few amps, so light dimming is no surprise. But, with the proper wire gage to feed that amp... #4 min., maybe #2 gage would be better here.
Am sure that "land yacht" has a pretty larger ALT/BAT in stock package... but would guess you may need to upgrade to a larger battery (800+ CCA rating) to reduce light dimming.
Do you know what size engine is in this car and what output rating on ALT.
Finally, what is the cf of your sub enclosure? I would say 1.25 cf internal per sub is about right sealed. If ported, probably closer to 2.0 cf internal and tuned to ~35 Hz. would be pretty solid bass here.
Swez
PS Do you have a web link to the Mobile Authority subs you are using now?
ZX2Xtreme on 06/12/2003 10:31:37
I Agree also with the wire size and the battery size. 800+ cca will help out alot. instead of 12 guage wire in the box use a 10 guage power wire, and from outside the box to the amp run 8 guage or so. that amp has 2 ga power/ground inputs, and 8 guage speaker inputs. TAKE ADVANTAGE OF THIS. And the box size should be a little closer to 1.66 cu ft per sub. we used to sell mobile authority and they needed rediculous space to pump bass. Id also check the phase of your subwoofers, out of phase is very common.
Hope this helps a little bit,
Xtreme
BigJMan on 06/12/2003 12:18:51
Thanks, I'm going to be replacing all my electrical wiring soon, and checking the dimensions on the enclosure - right now I don't remember how big it is off the top of my head, but it's the standard sealed two 12"s size that one can purchase from Best Buy, Circuit City, etc.
Swez -
Heres a link to Mobile Authority's Site http://www.mobileauthority.com/productcatalog.cfm?Class=354, the MN of the subs I have is M1295.
BigJMan on 06/12/2003 12:55:34
Apparently I'm either retarded or deserving of a good beatdown, cause on MobileAuthority.com they say that you need 1.75 - 2.25 cubic feet (per sub), and the w/ the box I'm using there's only 1.1454 ft3 per chamber! I'm thinking this might be part of the problem. What do you think Xtreme - Since you used to sell Mobile Authority, would this make a huge difference - going off of common sense and my own inclination, I think it would.
BigJMan on 06/12/2003 13:36:39
That 1.1454 ft3 figure is internal volume before subtracting the displacement of the subs, whose VAS is 58.
ttocs on 06/12/2003 14:15:28
add a little more then a pound of poly fill per side. You might be able to get what you want. Go to a fabric shop, it is a cheap way to try and fix it.
Most subs do operate around 1 cu ft which is what you have after displacement. But some like a big box, some like a little box.
You are not retarted, I don't want you to think that we are talking down to you. There is alot to learn to this hobby. In reality, you never stop learning about it.
Swez on 06/13/2003 20:51:54
From the spec sheet, I see you have a sub that realy needs ~2.0 cf (+/- 0.25 ) internally. That's a very odd combination sub box for a 12" woofer. Most brands, go 1.0 -1.5 cf/sub in very general terms, for sealed boxes.
The site even mentioned filling the enclosure with 65% polyfill... which is also very unusual as well. The only real comment I can say, is... to use the box size recommended by the manufacturer. If you can afford to give up ~6.0 cf (external) of trunk space for these subs and want some decent low bass response, that's what's needed.
Also, these are primarily SPL subs. The Fo = 40 Hz indicates these subs are great at ~55 - 100 Hz, but deep lows below 40 Hz will be lacking due to power handling and construction techniques used in this sub. Is designed ffor high efficiency, high output but the trade off is well balanced bass 35-80 Hz range.
The rest of the issues are more power feed needs to feed the amp, w/o straving the rest of the electrical system. Seems we covered all that already... so you have your work cut out for you now.
FYI: If you really want high SPL and good SQ, may wish to consider a few other sub options as the budget permits. We have a few favorites here... just ask if you wish to know more on that aspect.
Swez
I currently own a '92 Towncar, and as of right now I'm trying to get some real bass to even out my stereo system. It's a long history, but the short version is I bought a Rockford Fosgate amp that pushed 75w rms x 2 @ 4ohms and 2 R.F. 12" Subs that were 150w RMS each. Needless to say, I wasn't satisfied, so I got another amp - a Profile Clarus CL600, which pushed 150w RMS x 2 @ 4 ohms. My bass got twice as loud and I was happy. Recently, I've decided to upgrade to a Audiobahn A1500HCT, which being a monoblock amp, does 500w RMS x 1 @ 4 ohms, 1000w RMS x 1 @ 2ohms, and 2000w RMS x 1 @ 1ohm!. I decided to take a chance and get top of the line Mobile Authority 12" Subs(150 oz. magnets), each rated w/ 4 ohm impedance and 500w RMS power cosumption. I have them wired correctly so my amp sees a 2 ohm load, so they should be getting 1000w RMS right? My problem is that when I have these hooked up, with all setting on amp and headunit dialed in, they're not even quite as loud as my 150w Rockfords - how can this be? I know the amp is drawing power because everytime it hits it pulls so much power that all my light in my Towncar dim a significant amount. The amp is a brand new 2003 model with flames, straight from Audiobahn, I used to have a A1500HCX, but that one was defective. I'm using 12 gauge wire with the speaker connection inside the box, I've resealed the inside of the box with liquid nails, and as far as I know have a real quality setup.
Does anyone have any ideas about what could be wrong (w/ my electrical system or setup - whatever)? I realize that Mobile Authority may make crap subs (I'm going to get Audiobahn soon - look at my "Need Educated Advice Topic"), but being fully powered they should atleast hit harder than my old low-powered R.Fs. Sorry bout length of post, had a bunch of s**t to say.
Replies (8)
ttocs on 06/11/2003 12:23:02
we might be able to help.
Did you upgrade the wiring going to that shiney new amp with the flames? If not, what size pwr wires are you running? You should probably have a minimum of 4 awg for an amp that size.
Another option, did you put the shiney new subs in the same box? If so you might check to see if the airspace requirements on the two are similar, if not the same.
I'll check back shortly..
Swez on 06/12/2003 09:00:00
Yes, I agree with ttocks... power management issues and the right sub enclosure for these MA subs are probably your main issues.
That amp pulls a few amps, so light dimming is no surprise. But, with the proper wire gage to feed that amp... #4 min., maybe #2 gage would be better here.
Am sure that "land yacht" has a pretty larger ALT/BAT in stock package... but would guess you may need to upgrade to a larger battery (800+ CCA rating) to reduce light dimming.
Do you know what size engine is in this car and what output rating on ALT.
Finally, what is the cf of your sub enclosure? I would say 1.25 cf internal per sub is about right sealed. If ported, probably closer to 2.0 cf internal and tuned to ~35 Hz. would be pretty solid bass here.
Swez
PS Do you have a web link to the Mobile Authority subs you are using now?
ZX2Xtreme on 06/12/2003 10:31:37
I Agree also with the wire size and the battery size. 800+ cca will help out alot. instead of 12 guage wire in the box use a 10 guage power wire, and from outside the box to the amp run 8 guage or so. that amp has 2 ga power/ground inputs, and 8 guage speaker inputs. TAKE ADVANTAGE OF THIS. And the box size should be a little closer to 1.66 cu ft per sub. we used to sell mobile authority and they needed rediculous space to pump bass. Id also check the phase of your subwoofers, out of phase is very common.
Hope this helps a little bit,
Xtreme
BigJMan on 06/12/2003 12:18:51
Thanks, I'm going to be replacing all my electrical wiring soon, and checking the dimensions on the enclosure - right now I don't remember how big it is off the top of my head, but it's the standard sealed two 12"s size that one can purchase from Best Buy, Circuit City, etc.
Swez -
Heres a link to Mobile Authority's Site http://www.mobileauthority.com/productcatalog.cfm?Class=354, the MN of the subs I have is M1295.
BigJMan on 06/12/2003 12:55:34
Apparently I'm either retarded or deserving of a good beatdown, cause on MobileAuthority.com they say that you need 1.75 - 2.25 cubic feet (per sub), and the w/ the box I'm using there's only 1.1454 ft3 per chamber! I'm thinking this might be part of the problem. What do you think Xtreme - Since you used to sell Mobile Authority, would this make a huge difference - going off of common sense and my own inclination, I think it would.
BigJMan on 06/12/2003 13:36:39
That 1.1454 ft3 figure is internal volume before subtracting the displacement of the subs, whose VAS is 58.
ttocs on 06/12/2003 14:15:28
add a little more then a pound of poly fill per side. You might be able to get what you want. Go to a fabric shop, it is a cheap way to try and fix it.
Most subs do operate around 1 cu ft which is what you have after displacement. But some like a big box, some like a little box.
You are not retarted, I don't want you to think that we are talking down to you. There is alot to learn to this hobby. In reality, you never stop learning about it.
Swez on 06/13/2003 20:51:54
From the spec sheet, I see you have a sub that realy needs ~2.0 cf (+/- 0.25 ) internally. That's a very odd combination sub box for a 12" woofer. Most brands, go 1.0 -1.5 cf/sub in very general terms, for sealed boxes.
The site even mentioned filling the enclosure with 65% polyfill... which is also very unusual as well. The only real comment I can say, is... to use the box size recommended by the manufacturer. If you can afford to give up ~6.0 cf (external) of trunk space for these subs and want some decent low bass response, that's what's needed.
Also, these are primarily SPL subs. The Fo = 40 Hz indicates these subs are great at ~55 - 100 Hz, but deep lows below 40 Hz will be lacking due to power handling and construction techniques used in this sub. Is designed ffor high efficiency, high output but the trade off is well balanced bass 35-80 Hz range.
The rest of the issues are more power feed needs to feed the amp, w/o straving the rest of the electrical system. Seems we covered all that already... so you have your work cut out for you now.
FYI: If you really want high SPL and good SQ, may wish to consider a few other sub options as the budget permits. We have a few favorites here... just ask if you wish to know more on that aspect.
Swez
Copyright ClubKnowledge 2009 * All Rights Reserved
