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Speaker box question
Malakai - Nov 26, 2004
  Malakai Nov 26, 2004
Not really video game related, but I thought some of you might be into car stereos and such.

I just received a really nice, large speaker box that someone gave me. It has 2 tweeters built in, and 1 8" rockford fosgate speaker, which is one of the 4 subwoofer ports it has in it. So, it has 2 8" ports, 2 12" ports, and the two tweeters.

The problem is that it's only split into two sides, 1 12" and 1 8" per side, with no air block in between those two speakers.

Would I have to reverse polarity on two of the 4 speakers so that both speakers wouldn't be knocking each other silly? In other words, when the 12" speaker kicks in, the 8" speaker would kick out and vice versa. Would this work, or is it still a bad idea to use this method?

thanks

 Curtis Nov 26, 2004
It'd probably sound wierd. Depending on how your crossover is setup, you might get some phase cancellation or other strange sounding distortion. Do they sound bad now?

 Malakai Nov 27, 2004
Well, only one 8" speaker came with the box. Unless you count the 2 tweeters and another "piece" of a generic 8" speaker that rotted away. The tweeters and the rockford fosgate speaker sound pretty good, but then again, two speakers aren't banging air against each other right now.

The reason I brought up the polarity bit was because I've seen some bandpass box designs that actually used 2 speakers per side using up the same airflow, and from what I've read, the way they make the two speakers work together, as opposed to against each other, was to reverse the polarity on one of the speakers.

 Malakai Nov 27, 2004
BTW, This is a professionally made box, if anyone is wondering.. It's a kicker competition box, with the 12" speaker ports on the top, and the two 8" ports on the side. Each has a pop on black cloth/nylon? cover.

I still can't see why they would design the box like this... I'd rather each subwoofer have its own air space.

 lordofduct Nov 28, 2004
I dont know a lot in this area. But my friends all do, from what i hear if one sub is pointing vertically and another is pointing horizontally you can reverse the polarity of one so that the "frequency adds!" (yeah, ok) what the phrase basically means is that reversing the frequency of one is gonna help the bass kick harder in the same accoustal area! So, yes this process should help you out!

 Berty Nov 28, 2004
by reversong polarity you are putting the speakers 90degress out of phase. This is not good as the sound cancels each other out by a factor directly proportional to the amplitude of each source.

Im not quite sure at what your trying to achieve though, but changing polarity is not the key.

 lordofduct Nov 28, 2004
I did some searching around for ya... www.audioholics.com... explains what this design is. Its called an Isobarik Enclosure, where speakers are lined up in the same enclosure (no air blocks between them) They explain that it reduces "second order harmonic distortion". They continue to explain that its not the most efficient in design but allows for smaller space and maximal use of a smaller amount of power. They say Phase Out does happen from this which flattens out the bass a little.

I figure this box may have been designed to be an isobarik enclosure by prefference. So looking to get the best possible sound in all out of limited design is like trying to make SNES color on a genny. You are forfeiting the good of another design and taking the bad of this one... because this one has some good that you may want to utilize.

 Malakai Nov 28, 2004
It's definately not isobarik, but would be similar if it did take the reverse polarity. In fact, from the outside, it just looks like a normal box, with all four of the speaker ports on the outside (not 1 outside, then one behind it which you can't see, and not setup with one speaker normal, and the other installed backwards).

There are several possabilities, I suppose.. 1, it's an old design, from around 1989 if I read the date correctly. So, they might have built it, thinking that four speakers could just knock each other silly in this sealed enclosure, without doing damage to the speakers.. Or they may have designed it for the reverse polarity.

The last possability, which I highly doubt, is that it was originally designed as a passive radiator system, and then someone took out the 8" radiators and installed 8" subwoofers in their place.

If anyone has any other thoughts and ideas, let me know lol...

 Alexvrb Nov 28, 2004
Do you *have* to use 4 subs? Why not just get a pair of 12s and call it a day?

 Malakai Nov 29, 2004
Well, there are two reasons why I wouldn't want to just settle with two.. First, the box is huge, atleast 1/3rd larger than most dual 12" subwoofer boxes, if not larger. If I were going to just use two subs, I'd definately downgrade the size to something smaller.

The other reason is because the subwoofers that I'm putting in the box is only built for sealed boxes. I would have to seal the two 8" ports up, and that'd probably defeat the purpose of the box, due to the size of the box and extra airflow inside of it.

I guess I'll just have to experiment with it and figure out what sounds and works best...

 Pearl Jammzz Nov 29, 2004
why 4 subs? I don't get it. I rather have a real good high-end sound than just somethin that rattles my car.....I even think 2 12'' are outragous most of the time.

Course I am one to listen to lots and lots of rock/metal and not the hippidyhop jive stuff. All a matter of preference I guess.

 Malakai Nov 29, 2004
I would have settled for two subs, if I would have had a nice box for them. Actually, I was using just 1 10" subwoofer before this box was given to me. I hadn't even planned on getting any more right now, but as opportunity knocked, I came calling lol

I guess it would have been easier to just go with 2 10"S or 2 12"s though.. A lot easier. Luckily, I already had a really nice 4 channel crossfire amp that puts out 400 (50 x 4, 200 x 2) rms watts bridged and can take up to a 2 ohm load.

Awhile back, I planned on putting an lcd tv in the car and a ps2, but the only place I saw fit to install one (under the passenger side seat) just wasn't wide enough. The only other spot, which I luckily didn't test out, was under the back seat, which I thought I could cut out, but it turned out the gas tank was right there.. The power inverter and a lot of stuff was already bought. So, It was disappointing... Shoulda measured ahead..


  
	
	

		
		

			Originally posted by Pearl Jammzz@Mon, 2004-11-29 @ 09:26 AM



why 4 subs? I don't get it. I rather have a real good high-end sound than just somethin that rattles my car.....I even think 2 12'' are outragous most of the time.



Course I am one to listen to lots and lots of rock/metal and not the hippidyhop jive stuff. All a matter of preference I guess.




[post=124661]Quoted post[/post]


 Alexvrb Nov 30, 2004

  
	
	

		
		

			Originally posted by Pearl Jammzz@Mon, 2004-11-29 @ 09:26 AM



why 4 subs? I don't get it. I rather have a real good high-end sound than just somethin that rattles my car.....I even think 2 12'' are outragous most of the time.

Yeah, there are different sub designs, and some people just like that big flat thud that rattles the back of their Civic, producing a vomit-inducing metallic rattle now and again.

 Malakai Dec 1, 2004
Actually, I listen to a lot of different types of music, and rap/bass is very low on the list, but I want it to be able to do what it needs to when the bass is playing.. Korn even knocks pretty darn hard on some of their songs.

Another thing.. More subs don't actually have to mean = louder. Yes, one can put in two 12" 250 rms watt subwoofers, and a 500 rms watt amp, turn the thing all of the way up, and rag out the subwoofers pretty quickly, or just get an all out bad sound. Distortion, cliipping = blown speakers, sometimes blown amp. So, adding more subwoofers to the mix, turning down the amp to slightly below the RMS ratings of the subwoofers, etc, will make them sound better and last longer. While the possability is there to make them sound "louder" or "boomier," my intentions are to make it sound "smoother".

 Alexvrb Dec 1, 2004
I'm not saying you'd do it. Just that I've seen it, and it makes me ill. Subs can be used to properly reproduce bass, not just to bang your car.