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rordway 
Member - Posts: 8
Member spacespace
Joined: August 13, 2004
Location: United States
Posted: August 13, 2004 at 7:22 PM / IP Logged  

First off I have check out the site many times, first time post! :-)

I have owned 2 Alpine 10" Type-R 1041's and had them in a custom box in a standard cab truck, very pleased as they were ran by an Alpine 7894 head and JBL BP 600.1 mono amp.

I have now moved onto a 2002 Blazer Xtreme with 2 15" Type-R 1541's ran by an Alpine MRD-M1000 mono amp. All I have is the Bose 6 speaker/6 cd system (sold the 7894 as I went off to college last fall,bad move) so I have a Scosche line out box for signal from the rear speakers.

I will supply as much info as needed.

4 guage power wire 20 ft long, ground 4 ft long, amp 1000 watt class d mono, factory head unit (gm/delco)

1st ?: My subs cut out very prematurely, not even close to max excursion.(although the headlights dim a fair amount)  E-3 displays on amp defining "excessive current". Could this be due to the preout converter and the signal it is pushing out, maybe non standard 4 volts to the amp?

2nd? I had a 38"x18"x18" box 2" slot port in the middle,3/4 MDF, sounded ok, had few air leaks around subs but sounded ok, I just went to a sealed box,dual chamber 38"x17"x16"just a little smaller for more "hit" and in hopes that my SPL would be more consistant from 30-200Hz but to my dismay my box's SPL is greatest from 120-200, from 30-120 it is extremely quit and shaky.Is polyfill a quick answer or should i resort to ported, or do I just flat out need a bigger box?

3rd? so I have the 2 15's, I may be able to trade them in for 4 12's (Type R of course!), for response and more power, using roughly the same box vol. but i have been drooling for a type-x 12, months before their release, they look great but their DB rating is very low and at 1000 watts each, its pretty demanding on an amp. Like everyone I want power with minimal volume but I really into acoustics so i was a flat response from 30-200 for Sound Quality. Your help would be greatly appreciated. thanks Robert

customsuburb 
Gold - Posts: 1,813
Gold spacespace
Joined: January 17, 2004
Location: United States
Posted: August 13, 2004 at 9:13 PM / IP Logged  

1. Are your subs 2 or 4 ohm DVC?

2. A properly designed ported box should be louder ,at and above its tuning frequency, then a sealed box. You might need to rewire your subs to fix this so I need the answer to question 1 first.

3. If you want to play it even louder go with the 4 12's and at lower volumes you will get better SQ, because 15s arn't going to offer much SQ. A MRD-M1000 should be able to drive a Type X sub fine, dont worry about the DB rating. It dosn't dictate if a sub is louder then another.

dpaton 
Copper - Posts: 141
Copper spacespace
Joined: July 19, 2004
Location: United States
Posted: August 13, 2004 at 9:19 PM / IP Logged  
#1:
Off the top of my head, it's that 20' run of 4AWG that's the main problem. You'll lose nearly 6V (5.746V to be exact) when the amp is trying to revover from a heavy bass transient. Dual 1/0 is your friend here, with a about a volt of loss (1.145V). You amp is likely complaining that the power input is dropping too low when it's trying to recharge it's power supply capacitors (to about 8.25V in fact, about the same as when your starter is cranking). A single run of 1/0 will still eat up about 2.3V as a point of reference. TO get those figures I actually used 24', since that's the round trip wire distance for your amp, assuming the chassis is an ideal conductor (which it isn't). That makes these a little bit optimistic. To be safely in the real of less than 5% loss, you'd need tto run a pair of 4/0 cables, which is really quite insane in a car. A couple fo huge caps will help if you want to try and survive on a single 1/0 cable. Stickign with the 4AWG is a bad idea IMHO.
#2
It sounds to me like the box is mistuned, or perhaps when your amp is gasping for breath (see #1) it dumps the range that eats the most current. Is it bad at all levels? Try measuing it at 70, 80, 90, and 100dB @100Hz, and then record the relative levels at 30, 50, 70, etc. Try and get a more specific picture of what you've got vs what you want. It'll help us.
#3:
Small, Loud, Low. Pick two. For your 4+ish cuft box, 4 12s will get a little over 1cuft each. That sounds about right for most autosound 12s. Out of curiosity, how much SPL do you want out of your system? SPL and SQ dont' mix very well unless you change the setup (EQ, XO, etc) between them.
My $0.02
-dave
This is not a sig. This is a duck. Quack.
Alpine Guy 
Platinum - Posts: 2,478
Platinum spaceThis member has made a donation to the12volt.com. Click here for more info.spacespace
Joined: October 18, 2003
Location: Canada
Posted: August 13, 2004 at 9:30 PM / IP Logged  

First off, , E-3 means 1, your impedance is to low, or 2 your ground isn't good enough.   Since you say you have 2 swr-1541d, that means you can only wire them to 1 ohm, or 8 ohm, , that amp can only go to 2 ohm,  Im thinking thats your problem.  try wireing up 1 voice coil on each sub to the amp, , that will be a 2 ohm load, , see what happends.  If you can,. id bring them back and get 2 SWR-1521d.       As for changing to 12's, thats totally up to you, , if you listen to just rap then 15's is they way to go, , but if you listen to rock, it may be a good decision to go to 12's.

The box size seems good, , i hope you put a separator to make 2 separate chambers, lots of performance is lost if the same airspace is shared.

2003 Chevy Avalanche,Eclipse CD7000,Morel Elate 5,Adire Extremis,Alpine PDX-4.150, 15" TC-3000, 2 Alpine PDX-1.1000, 470Amp HO Alt.
stevdart 
Platinum - Posts: 5,816
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Joined: January 24, 2004
Location: Pennsylvania, United States
Posted: August 13, 2004 at 9:50 PM / IP Logged  

What LOC are you using?  Make sure you have one that is specific to the bose.  Normally, bose is pulled and torched with a flamethrower before tossed into the dumpster.

1.  Impedance too high, gain not set correctly.  Not due to input voltage.  Your subs may be wired wrong, and the gain may be too high on the amp.  Fix that problem before doing anything about number two. 

Build the box so that it performs well in the worst case scenario and, in return, it will reward you at all times.
rordway 
Member - Posts: 8
Member spacespace
Joined: August 13, 2004
Location: United States
Posted: August 13, 2004 at 10:07 PM / IP Logged  

My subs are dual 4ohm and I have them wired in parallel so I am getting a 2 ohm load to the amp, but if I am correct this value is just an average, so at times the resistance changes?

I thought that 20 feet of 4 was way too long but thats the length from the battery to right behind the back seat. I looked at a chart and theoretically i needed 2, maybe even 0 guage wire.I think maybe another problem is I bought this 8 guage wire from this chinese flea market and I swear when I stripped this stuff it was like not even 10 guage of wire inside, nearly 50% or more rubber/plastic coating, I was mad and ran out of funds so I just went with it.

I am going for 75% SQ and 25% SPL, the blazer's hatch rattles much more than i thought it would, so I am not into loud so much as the quality, I was from 30-200Hz to be at the same db level as much as possible.

As far as musical preference I hit everything from Rock, Metal Rap, Hip Hop, Country, and quite often bass demos,techno and mixes.

I also wanted your guy's opinions on the Optima yellow top battery, my local mechanic can get a good deal on it and I wanted to know if it was worth the investment?

By the way "Alpine GUy" how is the 9835 working for you? that seems to be next in line for my purchasing.

I'll try to get a pick of the subs and amp when I get the chance. thanks a bunch, everyone is great here.......and no I am not excited to go back to school in a week!

stevdart 
Platinum - Posts: 5,816
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Joined: January 24, 2004
Location: Pennsylvania, United States
Posted: August 13, 2004 at 10:14 PM / IP Logged  

Two dual 4 ohm subs cannot amount to a 2 ohm load.

http://www.sounddomain.com/shop/wooferwizard.pl?num_of_subs=2&impedance_of_subs=4ohm_dvc&x=103&y=13

Build the box so that it performs well in the worst case scenario and, in return, it will reward you at all times.
rordway 
Member - Posts: 8
Member spacespace
Joined: August 13, 2004
Location: United States
Posted: August 14, 2004 at 1:04 AM / IP Logged  

ok I guess it's a 2 ohm load with just one dual 4. but still I believe that Alpine can go down to 1 ohm, the amp has an on board temp and it never gets too warm, not even close to hot.

I have no gain on the amp but on the little scosche pre out converter box if i set it higher that 25% up it cause the subs to "pop" and quit early, again, leaving the "E-3" display on my amplifier. I really need a new head unit, i just dont like that converter crap....

DYohn 
Moderator - Posts: 10,741
Moderator spaceThis member has made a donation to the12volt.com. Click here for more info.spaceThis member has been recognized as an authority in Electrical Theory. Click here for more info.spaceThis member has been recognized as an authority in Mobile Audio and Video. Click here for more info.spacespace
Joined: April 22, 2003
Location: Arizona, United States
Posted: August 14, 2004 at 9:43 AM / IP Logged  
Your impedence is too low.  The amp cannot handle a 1-ohm load safely and remain stable.  Simple as that.
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rordway 
Member - Posts: 8
Member spacespace
Joined: August 13, 2004
Location: United States
Posted: August 14, 2004 at 10:20 AM / IP Logged  

so i have a few options, wire in series, get another amp to get a 2 ohm load to each, or get rid of the 15's and get one 12" Tyoe-X dual 4-ohm....man choices.......

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