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Forum nameAudio, Alarms, AV
Topic subjectfor those of you that know about speaker polarity
Topic URLhttp://forums.2gnt.com/dcboard.php?az=show_topic&forum=10&topic_id=5197
5197, for those of you that know about speaker polarity
Posted by trickedeclipse, Dec-31-69 06:00 PM
I just bought two audiobahn speakers (http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&category=18803&item=3004425968&rd=1), and since they are so nice looking from the bottom, i want to display them in a fiberglass box with the magnets facing up (speakers firing downward into box).

first of all, is this a stupid idea? should i just have one face down, and the other face up?

how exactly would i hook them up on a two channel amp? (they are dual voice coil) i've been told you have to hook them up the opposite polarity if they are facing down, so that they move backwards.

also, is there a way to bridge them off my amp? this amp: http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&category=18796&item=3002894407&rd=1

i don't know anything about dropping the amp's ohms, but from what i understand, this amp is rated at 2400 Watts RMS x 1 @ 1 Ohm stereo. how would i go about hooking these speakers up so that i get the most power from the amp?

also, do you guys think i got a good deal on this stuff from ebay?
5198, RE: for those of you that know about speaker polarity
Posted by Apocalypse, Dec-31-69 06:00 PM
As long as you keep the polarity the same on the subs you will be fine. If you only invert one, you need to switch the polarity on that one. And its not a dumb idea, they sound the same faced either way, and audiobahn is all about the bling, so use it.
5199, RE: for those of you that know about speaker polarity
Posted by OZ_GS, Dec-31-69 06:00 PM
If you are going for a certain volume for your enclosure don't forget about speaker displacment when designing your box.

Anyhow as far as the amp goes its listed at 2400 @ 1OHM MONO. When you bridge it, it will become a mono amp.

Since your subs are dual 4 ohm subs to get a 1ohm load you will simply run them parallel/parallel. When you run the voice coils parallel each speaker becomes a 2 OHM speaker. Then when you run each 2 OHM speaker parallel that gives you your 1 OHM load.

Basicly speaker wire from the amp to each voice coil. No funky + to - series wiring.

Chad
5203, RE: for those of you that know about speaker polarity
Posted by SPL_Eclipse, Dec-31-69 06:00 PM
^^^^ exactly, go + to + to + to + on the speakers, and the to the + terminal on the amp, then do the same with the negatives. ive heard questionable things about the audiobahn amps, though, so if you run into problems dont fret, just come back here for more wiring advice. :D

just to be anal....TECHNICALLY, you wold wire all of your +s on the subs to the NEGATIVE terminal of the amp, and all the -s from the subs to the POSITIVE terminal of the amp to retain absolute polarity throughout the system, however this does not necissarlily translate to better positive phase interaction throughout the spectrum, so its not absolutly necissary. try it both ways (only takes a minuite to switch the wires at the amp) and see what you like better.
5204, RE: for those of you that know about speaker polarity
Posted by audiophyl, Dec-31-69 06:00 PM
It really doesn't matter how you mount your subs. Polarity of the subs does significantly matter, however.

If you invert your subs, you will want to wire these guys in reverse polarity. This way, when the bass notes hit, the sub will fire "back into itself" and will give you correct phasing.

It you invert one sub and keep the other mounted in the box, you will want to wire the sub in the box "in-phase". The inverted sub will be wired "out-of-phase", which will put the car acousticly "in-phase".

Unfortunately, most people do not understand phasing in a vehicle.

In our particular vehicles, most of us install component sets into the door and dash. This does great, but phasing often comes into play. It's been my experience to wire the passenger woofer "out-of-phase".

Why do this, one may ask. Well...firing each woofer in "mechanical" phase doesn't always mean that the audio system in "acousticly" in-phase. You need to listen to various frequencies to determine the best phasing for the car.

Proper acoustic phasing is more important than proper mechanical phasing.

Good luck to you!
5210, RE: for those of you that know about speaker polarity
Posted by trickedeclipse, Dec-31-69 06:00 PM
EXACTLY why I came to you guys! i knew that speaker phase was going to come into play here. I greatly appreciate your help, and yes, i will try hooking the subs up both ways ( + AND -) as well as monitoring differant frequencies through the speakers in order to obtain the fullest spectrum. thanks again guys. points for your help.
5465, RE: for those of you that know about speaker polarity
Posted by bigslim, Dec-31-69 06:00 PM
>
>Unfortunately, most people do not understand phasing in a
>vehicle.
>
>In our particular vehicles, most of us install component sets
>into the door and dash. This does great, but phasing often
>comes into play. It's been my experience to wire the
>passenger woofer "out-of-phase".
>
>Why do this, one may ask. Well...firing each woofer in
>"mechanical" phase doesn't always mean that the audio system
>in "acousticly" in-phase. You need to listen to various
>frequencies to determine the best phasing for the car.


Ok, I'm one of those who doesn't understand this. I understand the physical/mechanical issue. However, to clarify, you are stating to switch polarity on the driver-side door woofer? What should we listen for when this happens? Sorry if this is a super easy question, but I'm not following. Thanks.
j
5469, RE: for those of you that know about speaker polarity
Posted by SPL_Eclipse, Dec-31-69 06:00 PM
old thread, but im bored, as usualy, lol.

they key eliment to what audiophyl was talking about is relative phse when two or more speakers are interacting. if you had a mono system with just one speaker, there would be no reason to talk about phase becuase its just one speaker. its always perfectly in phase (well, of course you do get reflected sound waves, but assume you were in an anechoic chamber for this example). its like dropping one rock into a pond. it produces perfectly concentric circles of waves around it. imagine those as the sound waves.

now you add a second speaker, or for our example, a second rock dropped into the water. depending on the physical location of the new speaker, its amplitude, and several other factors, you run into situations where the waves interact, either causing positive re-enforcment or cancellation. cancellation occurs when two waves that are 180 degrees out of phase with each other meet. the pressure wave is then nullified, resulting in no sound (although its rare for two waves to completely cancel each other out). positive re-enforcment occurs when the two waves are in phase with each other, and they sort of "add" up.

so the whole point is this: by reversing the mechanical polarity of the mid speaker on the passengers side, you are effecting the way the sound from that speaker interacts with all the other waves produced by the rest of the system. this could result in better or worse sound, and may make a certain song that sounded good before sound terrible, while a terrible sounding soung sounds great. you might wind up wiith a huge peak at 500hz and a huge valley at 2khz. theres a lot of experimentation involved in creating the perfect sound enviroment.
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