Wiring subs...amp..???

[M3Galaxie]

Ok, I've got to get a new amp and I don't want to screw it up...The subs are two 10" MTX 6000 4ohlm's. They are currently wired seperately so I had two pairs of sound wires running off of a MTX 4250D...one to each sub. I've been looking at a RockfordFosgate P300-1 as a new amp (sugested by a guy at ultimateelectronics). Do I wire it the exact same way...or since I'm planning on rewiring inside the box should I "bridge" the two subs together. Making it one 2ohlm pair of wires running to the amp?

I'm not real sure about all the the wattage rating I know that the subs can handle 250RMS...but if I "bridge"(not sure it's the correct term)them the Rockford is rated at 150w x 1 @ 4ohlms or 300w x 1 @ 2ohlms.

So does this mean I can run the two subs splitting the 150w @ 4ohlms getting 75w a piece? Or Bridge the two subs and run 300w @ 2 ohlms...getting 150w to each?.....

I hope this makes sense. My knowledge about this stuff is...well non existant at the this point...my other car just had an AM radio...lol

[coope]

i would bridge them just because it will sound better if u scared u will burst them just turn down the amp but i wil go with fosgate there really good amps and can push almost enything i had a punch 150 and was blowing the trunk off my shit

[ghettogeddy]

new fosgate sucks ass lol old fosgate is a must


also try wiring them in series liek this

ive drawn it with a bridged or mono amp

that should drop the ohms to 8 thinking there is only one sub but really 2 4ohm it also makes the work less but still at peak performance

[dlr1989]

I am not sure just how much you want to know. But here goes. I haven't looked up the specs on your subs or proposed amp so I will use what you have listed.

Lets look at speaker impedance (ohms) first. I am assuming a single voice coil in each of your subs. I also assume that your proposed amp has a single set of speaker terminals. Given the these conditions there are two options for connecting the subs.

Option 1 wire them in series like this amp->sub1->sub2->amp, put another way wire the + terminal of your amp to the + terminal on sub1 the - terminal on sub1 to the + terminal on sub2 and the - terminal on sub2 to the - terminal on the amp. When connecting in series like this you must add the impedances of both subs to get the total impedance that the amp will see. Therefore from the amp's perspective there would be 8 ohms (4 ohms per sub) of speaker impedance. You do not list an 8 ohm power rating for your proposed amp. It might work, but I don't recommend this option.

Option 2. Connect the subs in parallel, I suspect that this is what you mean by "bridge" them. In this case you wire the + terminal on the amp to the + terminals on both subs and the - terminal on the amp the - terminals on both subs. Connected like this two 4 ohm speakers will present the amp with a 2 ohm impedance. This option would be my first choice.

I am going to stop with as few technical details as I can. It is just too easy for me to jump into Electrical Engineer mode or Electronics Instructor mode and write volumes of dry information that you may not want to know. If you want the technical details and the math to support them just ask and I or someone else will be glad to provide that information. You might also try searching here at 3geez, I don't know for sure but I bet this topic has been covered in detail before.

Another source you may want to look at is the website www.the12volt.com. They have a number of on line tools and drawings to further explain and show how subs (and most all car electronics) can be wired.

[Steve_Si]

What you are planning is not an upgrade at all.

While the MTX amp appears to have two sets of speaker outputs, they are actually both from the same single channel. So your amp is already seeing a single 2 ohm load (your two 4 ohm speakers). Your amp is rated at 250w RMS at 2 ohms at 12.5 volts. This is better than it looks, because most amps are rated at around 14 volts.

So the rockford will give 300 watts RMS if it sees the same 2 ohm load. It is also just a single channel amp, even if it has two sets of speaker connectors (like my P6001 does). If the rockford is rated at 300 watts @ 2 ohms @ 13.5 volts (like mine is) then really it's only a very slight increase in power.

When your MTX runs at 14 volts (when the engine is going), it probably puts out around 300 watts anyway. Your two subs are sharing that 300 watts.

Both rockford and MTX tend to under-rate their amps, so it could be even higher.

If you want to upgrade, find one that is rated to put out at least 400 watts @ 2 ohms.

BTW any MTX or rockford single channel amp can easily handle 2 ohms.

[M3Galaxie]

Ok, Thanks guys...I'm not looking for an upgrade just to get the thump back in my ride lol...anyways so basic it was already wired at 2ohms because it was only a single channel amp...I'm gonna do some looking around today probably end up with an amp. I'll let you know what I get.

[coope]

[QUOTE=ghettogeddy]new fosgate sucks ass lol old fosgate is a must


second that motion

[M3Galaxie]

I picked up a MTX 300 X-series...all the wiring is on one side and it came with a remote gain knob and wire. I went with this one, because it was about $50 cheaper thank the Rockford. I also looked at an Alpine Vpower 400 mono, but I figured the MTX would have enough power for me....and it does.

[ghettogeddy]

I picked up a MTX 300 X-series...all the wiring is on one side and it came with a remote gain knob and wire. I went with this one, because it was about $50 cheaper thank the Rockford. I also looked at an Alpine Vpower 400 mono, but I figured the MTX would have enough power for me....and it does.

HOW MUCH DID U SPEND

[M3Galaxie]

$215....with tax

[ghettogeddy]

whats the wattage on that u could have gotten a new audiobahn 800 mono for like 130 shipped on ebay

[M3Galaxie]

600ish peak 340wRMS @ 2ohms...it's a little late to tell me that.

[baqnblaq]

Here's a question for you. Does each of your subs handle 250 rms or 175 rms a piece? If the subs 250 rms each... don't buy that amp. Resin is... if you under power any subs, it causes clipping. Clipping will cause either sub failure, amp failure, or even both at the same time. Its aways good to remember its better to over power your subs then under power them.

[dlr1989]

Sorry baqnblaq, but thats just plain wrong. It's overdriving a speaker, or other audio device, that is going to cause clipping and damage to the speaker. Putting more power to a speaker than it is rated for is a sure way to toast a speaker. The power rating of a speaker is simply the maximun power that the speaker can handle without damage to the speaker. The power rating on an amp should always be somewhat less than the rated power handling capablity of the speaker(s) that it is driving.

Edit: This assumes that nomial imedances (1 ohm, 2 ohms, 4 ohms, 8 ohms) of the amp and speaker(s) match. If the speaker imedance is less than what the amp is rated for then that can severly damage many amps. If the speaker imedence is greater than what the amp is rated for that also can be damaging but it is often times less of a problem but still not recomended.

Here's a question for you. Does each of your subs handle 250 rms or 175 rms a piece? If the subs 250 rms each... don't buy that amp. Resin is... if you under power any subs, it causes clipping. Clipping will cause either sub failure, amp failure, or even both at the same time. Its aways good to remember its better to over power your subs then under power them.

[baqnblaq]

Sorry baqnblaq, but thats just plain wrong. It's overdriving a speaker, or other audio device, that is going to cause clipping and damage to the speaker. Putting more power to a speaker than it is rated for is a sure way to toast a speaker. The power rating of a speaker is simply the maximun power that the speaker can handle without damage to the speaker. The power rating on an amp should always be somewhat less than the rated power handling capablity of the speaker(s) that it is driving.

Edit: This assumes that nomial imedances (1 ohm, 2 ohms, 4 ohms, 8 ohms) of the amp and speaker(s) match. If the speaker imedance is less than what the amp is rated for then that can severly damage many amps. If the speaker imedence is greater than what the amp is rated for that also can be damaging but it is often times less of a problem but still not recomended.

You might want to do a little research. Clipping is caused when a speaker does not get the power it needs. Look in any car audio book or even on the net. I do agree if you do overpower a speaker it can cause damage, but thats not clipping. Clipping will cause more damage to a speaker compared to overpowering. Before you call someone, make sure you have your facts straight.

[dlr1989]

Ok, maybe a discussion on clipping is in order then.

Clipping can occur at any point in the audio path. Clipping can occur when an amplifier or other device cannot produce enough output current to respond to a given input signal or frequency. If a speaker itself is causing the clipping then the speaker is being driven with more voltage or current, most likely current in the automotive application, than it is designed handle or a frequency that is outside of the range it is designed to reproduce. If you overdrive a speaker it is likely to cause clipping. If you overdrive an input to an amplifier it is going to cause clipping. If you overdrive an input to a preamp it is going to cause clipping.

And yes you do need to provide enough current to drive the speaker and that does require an amplifer capable of enough current output or you do have the possiblity of clipping again. This is what I call underdriven clipping. At that point I (just my point of view here, others would likely view the speaker as the source) would place the blame for clipping on the amplifer not the speaker. The main point here is that the amp would feed the speaker with a clipped signal. The speaker would not cause the clipping but rather would recieve the clipped signal. To cause clipping in this situtation the impedance of the speaker would probably need to drop below the amplifiers rating. Its more likely that amplifier will clip because the amps gain is turned to far up or is fed a signal from the head unit or preamp that is too high for the amps input or the amp is fed an already clipped signal from the head unit or preamp.

Clipping is going to occur when some device in the path of the audio siginal cannot respond completly to it's input signal. This will result in what is basically a flat place in the signal or in other words a DC signal. Would this be true flat place in the signal or a true DC signal. Probably not, actually it way more complex, but should be an accurate enough description for this discussion. This DC signal would then be applied as an input signal to the devices that follow it. Most audio devices do not like a DC input signal. Speakers really don't like DC input signals at all. The current flowing through the voice coil of the speaker generates heat, the more current the more heat, that must be in someway transmitted to the air, or other cooling method surrounding the voice coil. Damage to the speaker occurs in most cases, and yes there are other cases, because the clipped input signal or higher than speaker rated input current (read overdriven here) has driven the voice coil to one end of it's range of travel and holds it there, then heat builds up very quickly in the voice coil and damages the voice coil. Another common theory is that the voice coil is cooled by it moving in the air that surrounds it. If the voice coil is moving, yet has current passing through it, the heat cannot be dissipated properly, possibly resulting in voice coil damage.

The underdriven clipping will also cause heat buildup in the voice coil because of the the same reasons with damage to the voice coil as the end result, if done long enough. Even a lower current can drive a voice coil to the end of it's travel if the voltage is two high. Even if the voice coil does not make a full excursion to the end of its travel, heat build up can still be a problem because the voice coil may not be moving. Typically less current is involved in the underdriven case. That does not mean that heating and it's resluting damage won't occur, it just may take longer. The probablity of damaging a speaker from underdriven clipping is lower than overdriven clipping. Not impossible, just not as probable. In reallity, too low speaker impedance is a more likely to cause speaker or amp failure due to increased current flow than a low power amp. This whole underpowered subwoofer issue is an item of great debate and really is somewhat of an urban legend or myth. The tests I have read about were pretty extream and many were not very controled. While I beleive it is possible to damage a speaker or an amp in a underpowered set up, if you feed the amp with a clean signal and have the amp's gain controls set properly so you don't drive it to clipping or otherwise distorting, you are not likely to have a problem other than you might not be able to out thump the car next to you while stopped at a stoplight.

Similar problems occur in an amplifer. And again the enemy is heat buildup. With the result being smelly amplifier. Smelly because the smoke has been let out of it. And we all know that when you let the smoke out of electronic devices they don't work anymore. We all know that smoking is bad for our health. Likewise smoking is bad for electronics too.

The rated power specifications that are commonly given for speakers are the maximum power handling ratings and really tell you nothing about what is actually need to safely drive a speaker. Those ratings are only the upper limit. Many times subs are going have some what narrower input range both in frequncy (of course) and input power requrements. That can make amplifier selection more difficult because you shouldn't just look at the max power ratings of the amp and speaker.

My main disagreement with your previous post was with, and still is with, your statement.

Its aways good to remember its better to over power your subs then under power them.

Sorry, I should have been more specific in my previous post rather than reference your entire post and should have said something to the effect of it being questionable advise to most people setting up a car audio system. What you are describing is often termed amplifier head room. If, and this is a really big if, there is some method installed (fuses, circuit breakers, fast acting electronic circuit breakers) to prevent overdriving the speaker or very, very carefull monitoring of the power levels (not likely in automotive installations) to prevent overdriving the speaker, would be this be a good idea. Another common recomendation at the other end of the scale is that speakers should be rated at 3 times the rating of the amp driving them. This way even if the amp delivers a clipped signal the speaker is more likely to survive. This also will more likely keep the speaker in the middle of it's operating range rather than at the extreem ends. Better for speaker life, better for sound quality.

Oh yes, you are correct that overdriving (overpowering) and clipping are not the same thing. But they can and indeed do cause each other.

I suspect that we could debate words and terms like clipping for a long time with no benifit to any one. I think that we can agree that both overdriving and clipping are bad and must be avoided.

You might want to do a little research. Clipping is caused when a speaker does not get the power it needs. Look in any car audio book or even on the net. I do agree if you do overpower a speaker it can cause damage, but thats not clipping. Clipping will cause more damage to a speaker compared to overpowering. Before you call someone, make sure you have your facts straight.

[baqnblaq]

Agreed. Their both harmful.

[M3Galaxie]

Another amp down...
Same thing as before I go in my car and the subs were not doing a thing...checked wires and fuses; all lights are on, but nothing. I've had the amp turned up pretty good lattely and imagine the same thing happened as before. Unless I can find a way to fix it I'm just going to have to do without for a while. Been spending alot of money lately and don't have an income at the moment to justify another amp..isn't college great.

[ghettogeddy]

Ya Theres Got Be Something Wrong With Ur Wiring From The Subs To Amp

[M3Galaxie]

^ You know I just remember that when i opened the box up cause they were wired funky on the inside, but I fixed that; The wire on the inside of the box is pretty high gauge just slightly lower guage than the stock speaker wire. Do you think this could be the problem? I think it's rediculous, cause whoever put the box together is a moron for using such small wire on the inside.

[ghettogeddy]

^ You know I just remember that when i opened the box up cause they were wired funky on the inside, but I fixed that; The wire on the inside of the box is pretty high gauge just slightly lower guage than the stock speaker wire. Do you think this could be the problem? I think it's rediculous, cause whoever put the box together is a moron for using such small wire on the inside.

ya that could cause thme to overload id def move up to like a 10awg or 12awg

[AccordB20A]

lol my law is custom tuned ported box. fattest wires u can find and gooOOoooOOO

really all you really need for a good loud audio set up is one sub in a good box, two or four speakers in their stock locations fat cables and large amps matched to the speakers/subs u have but i spose if u wanna compete/show off you can go more...

[M3Galaxie]

Yeah I originally only wanted one 10" subs, but got a hold of two 10's w/ box and amp for a reasonable price...At the time. After buying another amp, and gonna have to rewir the box and most likely a the third amp...it's not such a good deal.

[ghettogeddy]

Yeah I originally only wanted one 10" subs, but got a hold of two 10's w/ box and amp for a reasonable price...At the time. After buying another amp, and gonna have to rewir the box and most likely a the third amp...it's not such a good deal.

next amp look for a audiobahn a8000t its a 800 watt mono and ill show u how to wire both up when u give me the model number for the subs


man they went down in price lol
http://cgi.ebay.com/AUDIOBAHN-A8000T...QQcmdZViewItem
78 shipped isent bad at aLL
HOPE THERES SOME AROUND WHEN I NEED ONE

[M3Galaxie]

^yeah man that's not bad at all...I'll have to think about it though. I'll check my stuff and see what it all is. I'm pretty sure my subs can only handle 250w rms...so I think I'll have to wire in a series to bring the ohms up.