4 12"mtx 7500 vs. 4 15" mtx 8000

[Jayhawkk 10+ year member]

I know I may catch hell with this but since i've gone to building a system I seemed to of dragged a friend down with me(his wife lets me know this daily) anyways he's set on 4 12's or 4 15's. Searching around for what is in his price range I came across mtx's 7500 and 8000 series subs

He wants spl and a lot of it. The box will be sealed and he has room for about 1.5 to 2 cuft per sub and these two subs seemed to prefer this size which is also one of the reasons I was looking at em.

Anyways, 4 15 8000's or 4 12 7500's for max boom given all things equal?

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[Goldtaz1 10+ year member]

I will quote another member of this forum by saying "Sealed boxes and SPL do not go together". If he wants SPL the box needs to be ported. So he has about 8 cubes to work with?? 4 12's would love 8 cubes ported and would be freaking loud. I personally would give them a little more if possible. 4 15's would definitely work in 8 cubes sealed, but like I said before "SEALED does not equal SPL".

 

[LBX2G 10+ year member]

well if u take 2 subs away and put the 2 12s in 8 or 6 cubes. THen it will get loud. But not as loud as a ported.

 

[denim 5,000+ posts]

if you have the money and the room and desire for 4 15's go for it

 

[Jayhawkk 10+ year member]

I dunno about this sealed doesn't equal spl. I personally am partial to sealed but for a wholeother reason but to say sealed can't or won't get loud is a bit off imho. I've sat in vehicles with 4 solo( old round ones) 12's that I could barely breath in and they were in just a plain rectangular box sealed. I've also sat in vehicles with as many as 18 12" mtx subs all sealed. Granted this was a decade ago and I haven't messed around with systems for a long while but when did sealed start becoming the opposite of loud?

If sealed vs. ported would mean the difference between 145 and 149 respectively that doesn't mean 145 isn't loud it just means it's not as loud //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif

 

[Goldtaz1 10+ year member]

Jayhawkk, you are correct. I would definitely agree that 18 of anything would make it pretty hard to catch a breath. Sealed is not the opposite of loud. Sealed is just simply not as loud as Ported. Building a Ported enclosure increases the efficiency of your equipment (drivers). In a line graph, a ported enclosure will yield higher peaks (SPL) at certain frequencies (namely the tuning frequency of your enclosure) yet have a steeper rolloff when you go above or below your tuning frequency. I would go to the site below and read up on why ported is better for SPL. Read everything they have on their site, I think you will find it useful as you create a loud system. Peace.

http://www.ddaudio.com/dd/caraudio/enclosureInfo/portInfo.asp

 

[squeak9798 5,000+ posts]

I had 4 12" Eclipse 88120DVC in a sealed box (hardly SPL subs) in the trunk of an '88 Bonneville (doesn't have fold down seats) running off of a RF bd1500. When I got metered my voltage was barely over 11V. I hit a 143.xdb on a Termpro mic (pre-Termlab sensor) that had been calibrated the day before. Pretty respectable for a sealed box from the trunk of a car without folddown rear seats, and on an eletrical system running well below par.

But, all things being equal, if someone is looking for a high-output system, ported is generally the way to go. Ported gains you ~3db on average, but at some frequencies it can be as high as 6-9db over sealed.

How much does your buddy have to spend? I assume he is a basshead, looking for more SPL than SQ?

 

[Jayhawkk 10+ year member]

Thanks for the link. I think he's in the range of 700-800 for the four subs. I was just cruising through ebay for dual 2 ohm vc's or single 4ohm vc's which is why I cam up with these two selections. I was looking at the solo L5's but couldn't find any in that ohm config on ebay and he won't get 4 of those retail in that price range.

I think that's his price range anyays. When I told him the price shipped for 4 mtx 15's he said 'cool'. Wish I had the room for a setup like that //content.invisioncic.com/y282845/emoticons/frown.gif.a3531fa0534503350665a1e957861287.gif

 

[Jayhawkk 10+ year member]

Had to look on mtx's archieves to find the 8000 series but it seems to be a pretty solid sub from the specs alone. The 7500 12's have an unusually high freq at 45 but the 15 goes down to 30...

Guess the appropriate thing would be 4 15" 7500 or 4 15" 8000

 

[squeak9798 5,000+ posts]

Just an idea; 4 Tempests? Two 15" Brahmas ported? Two 15" XXX ported?

 

[Jayhawkk 10+ year member]

I was thinking about the temests too but is there still a backorder? Seems some of the threads I was searchingthrough looking for subs had the adire brands taking a while to get done?

 

[Goldtaz1 10+ year member]

Tempests everyday, all day $150 shipped. Kyle is really cool, e-mail him just to be sure. He usually responds in a day or two.

http://www.acoustic-visions.com/~acoustic/products/subwoofer_drivers/adire_15_tempest/

You'll have to e-mail him about the Brahma's. Of course RE can get you some XXX's in no time flat, just call em and tell them what you want.

 

[Jayhawkk 10+ year member]

This has got to be the hardest freakin part about building a system. When you think you have a sub narrowed down out pops 10 more to choose from

 

[Jayhawkk 10+ year member]

Tempests won't work with the 8 ohm vc. only can get a 4 ohm load with 4 of em.

 

[Goldtaz1 10+ year member]

Correction, Tempests would yield a 1 ohm load if 4 of them were wired in parallel to a given amplifier. Tempests are dual 8 ohm voice coils. If you series wired them then you would arrive at a 4 ohm load. The only thing I will warn you of is that Tempests are extremely hungry for airspace.