hooking car sub to home theatre sub amp

I have aquired a nice pair of swr 1242D alpine subs but not yet have a car amp to power them so i figured why not have a go trying them inside just for kicks, i have a budget 200 watt sub amp which i want to wack at it just for kicks but dont know what the penalties will be. I dont care about the amp if it blows it blows but i am more worried about burning the subs from distortion, just want to be sure of the risk factors involved.
I understand the ohm differences as the amp is about 6ohms and is quite pathetic and will probably suck and die and the speakers are dual 4ohm = 2 ohm so there's quite a difference but i like to be dangerous and blowing things up haha :).

You can blow the subs by running an under-powered amp. However it depends how high you crank the volume, i.e. if you run the amp a say 50% or less you should be ok.

it depends how you connect them is 2 ohms it can be also 8 ohm

Well if each sub has a dual 4ohm voice coil, which is wired as 2ohm then you can wire the subs in series and reach 4ohm nominal impedance again. Or go the opposite way and wire the coil's up to 8ohm nominal and then back to 4ohm by wiring the subs in parallel. Either way you get the same end result though. Probably shouldnt wire them to be 16ohm nominal.

I still probably wouldnt hook them both up to a 200w amp though. Maybe if you just use one sub

Wire them to 4 ohms, amp shouldnt care as your reactive ohm load will likely end up between 5 and 7 ohms depending on the enclosure you are using.

As to blowing them with 200w, is that RMS or peak? If its RMS then maybe (peak wattage will be ~400w), but if its peak then I wouldnt worry as long as you arent running at full volume with the amp maxed out.

Quote:

---

Originally Posted by STEvil

As to blowing them with 200w, is that RMS or peak?

---

Each of those subs is 500w rms (peak is listed at 1500w) and have DUAL 4ohm voice coils wired in parallel to be 2ohm (for EACH sub)
Sensitivity is only 85db/1V (which is normally 3dm above the db/1w rating, so lets estimate 82db/1w). That means at 100db you would be drawing around 64w of power per sub. That may seem like enough, but the amp is a cheap amp he said so we really dont know if its 200w rating is continuous, id guess not. And it is harder to hear low frequencies and subs normally get pushed much louder than the rest of the system, so if he is watching at 100db, the subs will probably be 110db, and that draws well over the amps power capacity even if it were continuous rated (110db on that is pulling closer to 500w). hence my concern of running both of them on the amp, even 1 is pushing it IMO.

I hooked them up but sounded crap so i was like stuff it.

Quote:

---

Originally Posted by EniGmA1987

Each of those subs is 500w rms (peak is listed at 1500w) and have DUAL 4ohm voice coils wired in parallel to be 2ohm (for EACH sub)
Sensitivity is only 85db/1V (which is normally 3dm above the db/1w rating, so lets estimate 82db/1w). That means at 100db you would be drawing around 64w of power per sub. That may seem like enough, but the amp is a cheap amp he said so we really dont know if its 200w rating is continuous, id guess not. And it is harder to hear low frequencies and subs normally get pushed much louder than the rest of the system, so if he is watching at 100db, the subs will probably be 110db, and that draws well over the amps power capacity even if it were continuous rated (110db on that is pulling closer to 500w). hence my concern of running both of them on the amp, even 1 is pushing it IMO.

---

You left out box efficiency, room gain, and poor manufacturer ratings.

That aside, I was asking about the amp, not the subs.

Sorry petpeeve here.

Show me anywhere that proves a sub (or any speaker) can be blown by being underpowered.

Distortion itself does not damage speakers. Speakers have mechanical and thermal limits. If the power is within those limits the speaker is not subject to any harm.

However to add to the OP. dual voice coil subs are highly inefficient. You can hook it up by all means but do not expect to get any descent results out of it.

Quote:

---

Originally Posted by Bun-Bun

Sorry petpeeve here.

Show me anywhere that proves a sub (or any speaker) can be blown by being underpowered.

Distortion itself does not damage speakers. Speakers have mechanical and thermal limits. If the power is within those limits the speaker is not subject to any harm.

However to add to the OP. dual voice coil subs are highly inefficient. You can hook it up by all means but do not expect to get any descent results out of it.

---

More coils does not change efficiency. Efficiency is a product of the design of the overall motor (coil thickness, height, gap length and tightness, just for starters) , and beyond the first couple hundred watts doesnt actually mean a lot anyways.

If the driver is rated properly you can feed it as dirty of power as you wish with no issues, assuming your impedance sweep does not make the amp put out more than what the driver is rated at if you're using a full-on square wave.

Most drivers are not rated properly and most amps are rated even worse.

^^ What STevil said :-). 'Underpowering' stuff can be an easier way to drive things into clipping if volumes and gains are all turned to the upper most levels on poorly designed and improperly rated equipment. Clipping (square-waves) can kill improperly rated things. 'Underpowering' as is certainly wouldn't kill a speaker, otherwise every time the volume was turned down the speakers would overheat, and every time the system was turned off the speakers would explode.

Quote:

---

Originally Posted by STEvil

More coils does not change efficiency. Efficiency is a product of the design of the overall motor (coil thickness, height, gap length and tightness, just for starters) , and beyond the first couple hundred watts doesnt actually mean a lot anyways.

If the driver is rated properly you can feed it as dirty of power as you wish with no issues, assuming your impedance sweep does not make the amp put out more than what the driver is rated at if you're using a full-on square wave.

Most drivers are not rated properly and most amps are rated even worse.

---

Completely correct. However the design intent of car audio subs being dual or quad voice coil is to have better power handling and in that design they are typically less efficient and more difficult to drive than there single voice coil counterparts.

Quote:

---

Originally Posted by SabreWulf69

^^ What STevil said :-). 'Underpowering' stuff can be an easier way to drive things into clipping if volumes and gains are all turned to the upper most levels on poorly designed and improperly rated equipment. Clipping (square-waves) can kill improperly rated things. 'Underpowering' as is certainly wouldn't kill a speaker, otherwise every time the volume was turned down the speakers would overheat, and every time the system was turned off the speakers would explode.

---

Yes an improperly matched and set up system spells recipe for clipping. But in the case of subwoofers that's typically going to be the end of the amp's power supply but can pop voice coils or melt them.

Sent from my GT-I9100M using Tapatalk

Quote:

---

Originally Posted by Bun-Bun

Completely correct. However the design intent of car audio subs being dual or quad voice coil is to have better power handling and in that design they are typically less efficient and more difficult to drive than there single voice coil counterparts.

---

Actually it is to allow the end user to select which impedance best matches their amplifier. Power handling is dependent on construction of the overall motor and coil assembly and not the number of coils.

Quote:

---

Yes an improperly matched and set up system spells recipe for clipping. But in the case of subwoofers that's typically going to be the end of the amp's power supply but can pop voice coils or melt them.

Sent from my GT-I9100M using Tapatalk

---

Clipped signals can come from any device in the chain.

Yea from my experience the underpowered myth has always been overthrown too much as it confuses people, i think also the lower impedance from subs is to maximize the amount of power that can be drawn with less use for the dc to dc converter. You will never see any benefits to dual coils in home theater systems as they utilize a better system and power source setup so there's no need to "cheat" per say as they do in car audio systems.

I actually managed to get a cheap amp yesterday and hooked only one of the subs up but for a crap amp that it is it definitely puts out some sick sound, will just look out for a better amp for now so i can power them both with better quality power, least i have it all set up now so it will be easy when i do so.

No reason you cant build car amps that utilize higher impedance drivers, its just not done.. for some reason.

Its because the higher the impedance the higher the voltage that is required to maintain the wattage, the lower the the impedance the less voltage that is needed and less dc to dc transfer that has to be done. Basically its more efficient as there's less power loss and less processes the signal has to pass through.

That's exactly it. Lower impendance are more efficient in the sense you can draw more power from car amplifiers easier.

multiple voice coils are utilized to pull more power from amplifiers or use multiple amplifiers. Highly efficient subs typically will not have other options than single voice coil as they will not need to be configured in such a way to need high power low impedance amps.

That is what I meant by dual voice coils are typically not efficient. to beef up a sub to handle more abuse will need more power and multiple coils are used to pull more power from amp(s).

And yes you can make amplifiers in cars to put out high power at higher impedances but they are more expensive.
Sent from my GT-I9100M using Tapatalk

Its the same with inverters, the more power you want to go from dc to ac the more expensive it is because of the bigger and better diodes required to provide the transformation.
Its a nail stuck because yes its efficient but not in terms of saving power but in getting the most out of the system with the least amount of power loss while doing so.

Building a car amplifier to put out more voltage isnt exactly hard, you just step up the voltage a bit more with larger coils. Yes, I agree its slightly less efficient than going from a direct ~115v AC source, but then again most car audio amplifiers use a ~10:1 step-up from 12-14v already anyways, thus they are running 120-140 volts internally, the same as many house amplifiers. Its not expensive to do, its just not done because most car audio equipment is designed to run at lower impedance, so building for higher does not give you an edge over your competition and mostly only puts you at a disadvantage.

Again, the only reason for the multiple coils is to allow multiple wiring options. If the manufacturer choses to use heavier gauge wiring in the coil that is their prerogative but does not change the fact that multiple coils do not change efficiency of the motor design unless you specifically make them do so. I agree that typically automotive applications will see higher distortion and more clipping so the efficiency rating does take a hit from parts being overbuilt to withstand this.

As to use of multiple amplifiers, strapping requires that the amplifiers are connected to each other through the voice coil(s), unless you like gain-matching..

Also I will comment that generic consumer grade automotive equipment is not the greatest quality so efficiency being lower isnt a suprise. That said, professional audio equipment has been quite stagnant in development for the average consumer.

I've done it in the past, it's just that 4 ohm speakers heat the amp up a more then usual.
For example, back in the day with a top of the line sony receiver (not brand perhaps but there top of the line model)...
If you crank up the volume past halfway it will overheat within a few mins and shutdown on it's own, protection.
The older models didn't have such protection.

Regardless, a 100w or so is enough anyways.
Bleh, anyways, if you hook a 4ohm to a home deck, keep it under half for the volume and you'll be fine.

I had 2x15in 750w 98db pyramid's hooked to mine.
Way back in the day.
Mech warrior was the sh!z like that lol.
It blows away any sort of computer speaker setup.

Make sure if you do use subs to use a crossover on each channel...
At the very min at least for the subs themselves if not for the rest of the config.

Edit:
Also...
To get 8ohms out of 2x 4ohm speakers you must hook them in series.
To get 4ohms out of 2x 8ohm speakers you must hook them in parallel.

Most home receivers will work fine at 4 ohms, for example the "A" and "B" outputs for the front are usually connected internally, so putting two sets of 8 ohm speakers on them results in a 4 ohm load.

Quote:

---

Originally Posted by STEvil

Again, the only reason for the multiple coils is to allow multiple wiring options. If the manufacturer choses to use heavier gauge wiring in the coil that is their prerogative but does not change the fact that multiple coils do not change efficiency of the motor design unless you specifically make them do so.

---

Yea your right i should have stated just impedance not indicating it towards the dual coil.

Got a new amp the other week (alpine mrp-mr650), its a 600 watter and it had the power with little distortion but the accuracy was really bad to me with peak spl at aroung 70-80 and then evening off below and after those points. Making it a little distracting hearing bass guitars playing when one frequency sounds louder than another semi octave above or below it etc.
So went back and got a kicker (ex500.1) amp and it is a lot accurate compared to the alpine but some how i feel it lacks in power, seems as though it distorts when hitting heavy or hard sub frequency's so I'm left yet again to find another amp to power at least one speaker really well. Any suggestions ?.

Weird for the alpine to do that. Sure the crossovers and subsonic filter were set right?

I use memphis amps for for my subs.

Sent from my GT-I9100M using Tapatalk

probably poor box in combination with amp settings and/or receiver/head unit. Boxes that work ok in vehicles usually do not do well in home :p