SUBWOFFER AMP QUESTIONS

[Pilot]

I just got a MK1 that has a 4-channel amp, that is supposedly 1000 watts, already installed in the rear trunk but no sub-woofer speaker(s). If I am reading the amp instructions correctly, to add a sub-woofer, I would need to change to a 2-channel configuration for the front/rear speakers and then use one of the other channels for a sub-woofer. There is no instruction on how, if feasible, to wire for two sub-woofers. So am I limited to one, or can I wire two sub-woofers in parallel or...? Will it sound good with just one sub-woofer?

Any suggestions for behind the seat MK1 sub-woofer installations that will not interfere with seat operations? Is it best for the sub-woofers to be aiming straight up at the car top or angled and aiming at the back of the seat or...?

Thanks for any tips.

[muffinman]

Originally Posted by Pilot

Will it sound good with just one sub-woofer?

Any suggestions for behind the seat MK1 sub-woofer installations that will not interfere with seat operations? Is it best for the sub-woofers to be aiming straight up at the car top or angled and aiming at the back of the seat or...?

Yes it will sound good with just one sub. the direction does not matter with subs. what's the brand and model number of your amp?

[Pilot]

Originally Posted by muffinman

Yes it will sound good with just one sub. the direction does not matter with subs. what's the brand and model number of your amp?

Thanks for the tip about mounting. The amp is a PYLE PLA885



The way the wiring is currently connected is as follows per the amp manual:



If I want to put a sub-woofer into the system, I believe what I need to do is connect both front and rear left speakers to the left terminal and front and rear right speakers to the right and the sub-woofer as follows:



But, if I should opt for two sub-woofers, would I just connect them in parallel to the same terminal or...?

[Pilot]

Come on you techies...whose got the answer for the question above...

[traintech86]

from what i read, most people just use a pair of 8" subs or maybe 10's. someone will chime in tho

[MANDALAY]

Instructions are the on the amp . look at the diagram.
My suggestion is run one sub , because bridging the 2 channels will have the impedance therefor 2 ohms. If you use 2 subs parallel effectively 1 ohm. I think bad news for your amp, Given the very little fuse and the
WARNING MINIMUN 4 OHM SPEAKER IMPEDANCE.

Dont take this the wrong way i believe you should leave it to the professionals as you might just one day see your car in flames

[sabing]

running two subs off a 4 chan isnt usually a good idea. Unless you use two channels per sub then use your deck for the speakers.. For 2 channels bridged to power 2 subs the amp would need to be pretty crazy. Some people don't know it but underpowering a sub can blow it out just as easily as overpowering it. Check out crutchfield.com for wiring diagrams on how to achieve different ohm loads

[Pilot]

Originally Posted by sabing

running two subs off a 4 chan isnt usually a good idea. Unless you use two channels per sub then use your deck for the speakers.. For 2 channels bridged to power 2 subs the amp would need to be pretty crazy. Some people don't know it but underpowering a sub can blow it out just as easily as overpowering it. Check out crutchfield.com for wiring diagrams on how to achieve different ohm loads

If I run the front speakers using two channels of the amplifier and the rear speakers powered by the deck only and a single sub-woofer powered by the other two channels--is this likely to produce satisfactory results?

[MANDALAY]

You dont need rear speakers at all

[MANDALAY]

Originally Posted by sabing

running two subs off a 4 chan isnt usually a good idea. Unless you use two channels per sub then use your deck for the speakers.. For 2 channels bridged to power 2 subs the amp would need to be pretty crazy. Some people don't know it but underpowering a sub can blow it out just as easily as overpowering it. Check out crutchfield.com for wiring diagrams on how to achieve different ohm loads

Running at the wrong frequency is what kill speakers.
Ive run 1000 watts rms into a factory 5 inch driver with out killing it . All frequencies below 800 hz were removed.

Half a watt with a 50 hz signal in a tweeter will kill it

wrong frequency is the main reason equally followed by not enough power as distortion will be the out come because of the need for extra loudness

BTW my competiton cars tweeter are run with 1000 watts rms

BY BIG AMPS

[Pilot]

Originally Posted by MANDALAY

BTW my competiton cars tweeter are run with 1000 watts rms

BY BIG AMPS

My son's MR2 came with what is marked as a 1000 watt amplifier. Very bling looking amp as well with its see-through top. When the radio shop installed a new radio, they were quick to point out that amplifier manufactures often make amp power claims that are significantly exagerated--they lie. He reminded me that all I have to do is look at the circuit breaker associated with the amplifier (30 amps on my son's car), multiple that number times voltage (12) to get the maximum wattage the unit can produce...in this case (12volts x 30 amp fuse) 360 watts. So what is YOUR circuit breaker size?

[MANDALAY]

Your maths is correct. Also thats probably maximum so divide by 1.4 for RMS . So most likely about 80 watts and since music is dynamic with around 10 db crest factor , that amp would only play around 20 watts continuos without distortion.
When an amp has big claims they generally are not true.

You sitting down 120 amps.+ and - cables to all my amps are either 4 or 1/0 gauge.
See simple math for every doubling of power you need 3 db
1 watt 3 db
2 watt 6 db
4 watt 9 db
8 watt 12 db
16 watt 15 db
32 watt 18 db
64 watt 21 db
128 watt 24 db
256 watt 27 db
512 watt 30 db
1024 watt 33 db
2048 watt 36 db
most speakers ar about 87- 90 db efficient so a 2048 watt amp will only play 120 db
remove the crest factor and you get 110 db

[sabing]

Originally Posted by Pilot

If I run the front speakers using two channels of the amplifier and the rear speakers powered by the deck only and a single sub-woofer powered by the other two channels--is this likely to produce satisfactory results?

Yes that should suffice. Front speakers are main sound and backs you barely hear any of, so yes that setup would be good. Just make sure you check out what Ohm rating the amp can handle and wire the subwoofer accordingly.

[MANDALAY]

^ surfice maybe if your lucky. Unless they are time aligned it will do little but only to confuse the front stage. Which also brings up the point of using a 4 channel amp to wire a pair for the sub and the other 2 for the front stage , unless the amp has a phase alignment adjustment you will have problems that can be heard. It can only be swapped 180 degrees by changing the polarity around but the subs will be very close to you ( in a MR2 ) so greater flexibility is a must. See OEM systems have already taken this into consideration and why a lot of systems might sound louder are really not accurate

[traintech86]

Originally Posted by Pilot

My son's MR2 came with what is marked as a 1000 watt amplifier. Very bling looking amp as well with its see-through top. When the radio shop installed a new radio, they were quick to point out that amplifier manufactures often make amp power claims that are significantly exagerated--they lie. He reminded me that all I have to do is look at the circuit breaker associated with the amplifier (30 amps on my son's car), multiple that number times voltage (12) to get the maximum wattage the unit can produce...in this case (12volts x 30 amp fuse) 360 watts. So what is YOUR circuit breaker size?

i wonder if this is like computer power supplies:

they take them and put them in a controlled place, and then run the test. they'll say it makes 500 watts but they don't tell you that they got that info at insane low temps. then when you put it in your computer case, the temp goes up and the output hits far lower then their test.

i am not sure if temps will affect the amp but there must be some way that they bs'd the number. if thats the case, i am sure if you pay a little more, there are companies that won't test under controlled spaces(or at least lie to you a bit less). can anyone who is amp savy chime in ? O_o

[sabing]

Well there never used to be any regulations on how they tested them, so yes, they could test them in ice water upside down and backwards if they wanted. Most new brand name amps are CEA certified now so you can compare them with an official benchmark.

[MANDALAY]

Believe it or not 10 - 15 years ago USA made amps were probably the best in the world.
Out side testers like Auto 2000 gave full results and evaluations . Now most are build in asian countries, what a shame. Ledgendary companys like RockFord fosgate.
Power of an amp is not the only thing , there are also manyyyyyyyyyyyyyy other factors in selecting an amp. I could write a book.
But ill bet my 1997 USD made Soundstream amps against any amps of today , period.
Head units were at their peak then to for specifications and they have only gone backwards
Again ill put and bet anyone to ever challenge my 15 year old Apogee D/A converter. Simply the best it the world.
Only thing is at that time i payed $6000 USD whereas today you can buy them for only $800.
Car audio is not witch craft , its full of bull**** marketing and reps only wanting to sell their product with exaggerated claims.
While i was taking a break b/w my chosen field i was a rep for an auto shop.
Word got around and in only 2 months sold $200,000 of audio gear !!!!!!!!!!!
Why ? because i showed them the truth in between the bull****.

[MANDALAY]

But on another note , and old saying i have , " if your happy with what you have , then i am happy "
I have a mate in Tasmania that builds home amps . Cost around $250 and ill put then against any other amp , krell >$5000 or anyone else.

[traintech86]

its been this why with our country for a while now. made in USA used to mean something... maybe 1 day the corps will pull their heads out of their asses and un**** themselves... probly not but we can hope >>

[Pilot]

Originally Posted by MANDALAY

... bridging the 2 channels will have the impedance therefor 2 ohms. If you use 2 subs parallel effectively 1 ohm. I think bad news for your amp, Given the very little fuse and the
WARNING MINIMUN 4 OHM SPEAKER IMPEDANCE...

Would I confirm ohms on a particular speaker channel by disconnecting a particular circuit from the amplifier and connecting an ohm meter to the two leads of that particular circuit or...?