Amp/sub wiring help!

[SkeeboSi]

okay, I've got a JL audio 12w3, and an alpine MRV-F345. Channels 3 and 4 are bridged to the sub, but the installation tech said that "it wont bump as hard as you might think cause we had to wire it parallel to run 8-ohms."
Can I/should I re-wire the sub so that it runs in series at a D2, 4-ohm impendance? or will this amplifier not be able to handle it? I dont want to burn anything out, but I'm not going to have that much potential in my car be wasted from wiring. Any suggestions?

 

[j_fukin_t]

hmm 4 channels are meant really for mid's and highs to be honest, i'd look for a mono amp and save that one for your highs, you'll be running that amp at capacity which i wouldn't recomend, i'd just wait and get a 2 channel or a mono amp

 

[1999stockaccord]

mono amp is ideal, but a 2 channel would do just fine with a hpf

 

[TiiM iiS l3eAsT]

if u only have one sub get a mono amp for sure...but even if u have a 2-4 subs get a mono amp...they run best and have better rms ratings on it

 

[SkeeboSi]

i know getting a second amp is ideal, but i just can't afford it right now. After figuring some things out I have this last question:
so on the amp, it runs 150 watts x 4 @ 2-ohms, and when you bridge two channels it lowers the ohm level. So bridging 3/4 together will make it 300 rms x 1 @ 1-ohm. (im not sure) while the 4-ohm sub will be in a parallel circuit to produce 2-ohms of resistance. is it still ok to run that set-up even though the sub will be at 2 ohms and the bridged channel powering it will be at 1 ohm?

 

[Brent878]

i don't think bridge the amp channels will affect the ohm's. The ohm's are determined by the speakers and not the amp. Most amps run the best at 4 ohms, some are 2 ohm stable and some are even 1 ohm stable. Running it at 4ohms should be no problem, if anything it will run alittle hot if it is being overworked. And a good amp will have a heat sensor and shutdown or turn on fans.

I am kinda tired and can't think right at the moment, but the 12W3 is a dual voice coil and you are running a single sub. So for you to be running at 8 ohms that means you are running the sub in a parrell connection which makes your sub a 4ohm sub. If you were to run it in series that would leave you at 2 ohms to the amp. But that is only if i understood your inital question correctly. If this is the case you will need to check if your amp is 2 ohm stable when bridged. And it probably still wouldn't hurt too much to try it out just be aware of how hot it gets.

 

[SkeeboSi]

i don't think bridge the amp channels will affect the ohm's. The ohm's are determined by the speakers and not the amp. Most amps run the best at 4 ohms, some are 2 ohm stable and some are even 1 ohm stable. Running it at 4ohms should be no problem, if anything it will run alittle hot if it is being overworked. And a good amp will have a heat sensor and shutdown or turn on fans.

I am kinda tired and can't think right at the moment, but the 12W3 is a dual voice coil and you are running a single sub. So for you to be running at 8 ohms that means you are running the sub in a parrell connection which makes your sub a 4ohm sub. If you were to run it in series that would leave you at 2 ohms to the amp. But that is only if i understood your inital question correctly. If this is the case you will need to check if your amp is 2 ohm stable when bridged. And it probably still wouldn't hurt too much to try it out just be aware of how hot it gets.

The wiring options chart (came w/ subwoofer) says running the D4 in a series will make it run at 8-ohms, and running it in a parallel will have it run at 2-ohms.
How can I find out at what ohmage my amp is stable when the bridged channels (3/4) are running 300 watts?
If it is 2-ohm stable, will it be safe to run the d4 parallel to 2-ohms?

 

[Brent878]

From what you have posted if they are giving 2-ohm rating then it is most likely stable. With my experiences 4 channel amps are not made for subs so thier low pass cross over's aren't the best and they tend to run hotter than sub amps but i haven't had any die on me. You will just be running the amp at its max where usually when you have 6.5 or 6x9's on the amp you won't use as much juice. I say go for it but if you like bass then you will probably end up with a sub amp later. I would suggest a bandpass box, it will be louder and deeper than a sealed box for amp and sub.

 

[cujo613]

your best bet with the amp is to leave it at 8 ohm bridged. The Alpine amp is not capable of 2 ohm. It will shut the amp off or damage it. That amp really wont do the sub justice. The alpine mono is a better choice, but if you leave it in, leave the 8 ohm wiring

 

[Zoot187]

Keep in mind that the lower the frequencies you are making the amp reproduce cause the impedance of the sub woofer to go lower as well, which is why so many bridgeable units are not good choices for doing what you are doing. Speaker impedance drops=increase on the load to the amp. Keeping a healthy load on the amp by wiring it at 8 ohms is the safer bet to preserve your amp at the expense of some low end volume. Been a lot of years in the audio world, and very few companies make units that can effectively deal with the whole musical spectrum. Running a single mono bloc amp for your sub has always been the best way unless you are going to spring for ADS, or MacIntosh.

 

[Brent878]

Keep in mind that the lower the frequencies you are making the amp reproduce cause the impedance of the sub woofer to go lower as well, which is why so many bridgeable units are not good choices for doing what you are doing. Speaker impedance drops=increase on the load to the amp. Keeping a healthy load on the amp by wiring it at 8 ohms is the safer bet to preserve your amp at the expense of some low end volume. Been a lot of years in the audio world, and very few companies make units that can effectively deal with the whole musical spectrum. Running a single mono bloc amp for your sub has always been the best way unless you are going to spring for ADS, or MacIntosh.

I have a MacIntosh system that I am not using. I don't have a car to install it in anymore and if anyone is interested let me know. I have it setup to compete in a the 151-300 class, its one 50x2 amp, and a 50x4 (200x2 if bridged) amp with 2 10 inch subs and 2 6.5 inch mids with cross overs. My head got stolen out of the car so that is all that's left. Great stuff for sure but on the expensive side if your not competing.

 

[Zoot187]

I have a MacIntosh system that I am not using. I don't have a car to install it in anymore and if anyone is interested let me know. I have it setup to compete in a the 151-300 class, its one 50x2 amp, and a 50x4 (200x2 if bridged) amp with 2 10 inch subs and 2 6.5 inch mids with cross overs. My head got stolen out of the car so that is all that's left. Great stuff for sure but on the expensive side if your not competing.[/QUO

What model numbers are the Mac amps? And how much do you want for them ? ]

 

[J32a2OwnsU]

Check your amps specs to see if it can run 2Ohm stable... if it does, then wire accordingly....

Keep in mind that the lower the frequencies you are making the amp reproduce cause the impedance of the sub woofer to go lower as well, which is why so many bridgeable units are not good choices for doing what you are doing. Speaker impedance drops=increase on the load to the amp. Keeping a healthy load on the amp by wiring it at 8 ohms is the safer bet to preserve your amp at the expense of some low end volume. Been a lot of years in the audio world, and very few companies make units that can effectively deal with the whole musical spectrum. Running a single mono bloc amp for your sub has always been the best way unless you are going to spring for ADS, or MacIntosh.

It does? I have NEVER heard that, EVER.

(doesnt mean its not true, but you have to link me to something that PROVES it)

 

[Zoot187]

Check your amps specs to see if it can run 2Ohm stable... if it does, then wire accordingly....

It does? I have NEVER heard that, EVER.

(doesnt mean its not true, but you have to link me to something that PROVES it)

I don't have a link to send you to right at the moment, as I only just noticed your response tonight.
However, if you take notice of any speakers impedance specification it always reads: X ohms nominal.
Nominal implies the variance based on the frequency that the speaker is being called upon to reproduce.
Since the voltage output to a speaker is constant at 2.83 volts, when speaker impedance dips, by way of Ohms Law, the amp must produce more current (amps) to rise to the challenge of maintaining the 2.83 volt output when the speaker impedance dips with the frequency.