RMS Question - Page 2

MattismodderX · 12-08-2010, 12:39 PM

Quote:

Originally Posted by Bigshot44

Thanks everyone for all the info. Now all I got to do is figure out how the hell I'm going to fit a 6.5 cubic foot box in my trunk.

it will fit. the 18" box that im still *****ing waiting on full specs is a little over 7 cubic feet. and thats with the sub firing upwards so it cant be too close to that metal that separates trunk from backseats. ull be fine if u measure right

Cashdollar2009 · 12-08-2010, 01:40 PM

What do you need 6.5ft^3 for man? You could fit two of those subs in there?

Afugy · 12-08-2010, 08:58 PM

My box took up 8.1 cubes and is 140 lbs without the speakers in it. If you're worried about it, before you build the box make a cardboard mock up of how big the box will be.

Bigshot44 · 12-09-2010, 02:47 PM

Quote:

Originally Posted by Cashdollar2009

What do you need 6.5ft^3 for man? You could fit two of those subs in there?

Its a competition sub

Bigshot44 · 12-09-2010, 03:04 PM

Figured id post some pics of current system while im at it :P

Cashdollar2009 · 12-09-2010, 03:37 PM

Quote:

Originally Posted by Bigshot44

Its a competition sub

You're really dropping it into a competition setup and tuning to 55Hz? You do know that you should NOT play music through those boxes right?

MattismodderX · 12-09-2010, 03:43 PM

Quote:

Originally Posted by Bigshot44

Its a competition sub

even the soundstream xxx 10,000RMS 15 needs a max enclosure of 6 cubes with a 3 minimum. i think with the 800rms sub 6.5 would be overkill. unless it has a crazy soft spider. ive had two different 12"s in a single 3.9 cubic foot box. now due to the boxes design it did pretty well but it made my first 12 (Fi BL 12) extremely soft. moving it back and forth was pretty funny. second sub was a lot stiffer but i still think it would have sounded a lot better in a 2.25 cubic ft box. u should run the specs of the sub through one of those box design software programs

MattismodderX · 12-09-2010, 03:48 PM

Quote:

Originally Posted by Cashdollar2009

You're really dropping it into a competition setup and tuning to 55Hz? You do know that you should NOT play music through those boxes right?

i saw that and i thought hmm that doesnt look right. maybe its wrong or some asian diagram with a misprint. now it all makes sense

Bigshot44 · 12-09-2010, 04:02 PM

k well ill upload all diagrams of boxes you guys tell me which is best for SPL but can still be used regularly.

MattismodderX · 12-09-2010, 04:06 PM

this one . it says inside has 1inch of fiber glass. thats some pretty thick fiberglass there. or does it mean a total of 1" from the 3/4 MDF and 1/4 of fiberglass

if youre a g at making boxes do the bandpass

AleroB888 · 12-09-2010, 04:13 PM

Quote:

Originally Posted by MattismodderX

this one . it says inside has 1inch of fiber glass. thats some pretty thick fiberglass there. or does it mean a total of 1" from the 3/4 MDF and 1/4 of fiberglass

1 inch "fiberglass" insulation / damping material, but I'd use a different type....

Bigshot44 · 12-09-2010, 04:21 PM

Quote:

Originally Posted by AleroB888

1 inch "fiberglass" insulation / damping material, but I'd use a different type....

recommendations?

Cashdollar2009 · 12-09-2010, 04:35 PM

I'd design your own ported box based upon online specs and recommendations. With this, you can decide what your goals are for this subwoofer application. Whether it may be rock music, hip-hop, c&s, or just overall musically sound. The design you were originally looking at was that of what many refer to as a "burp box." A design made to match the subwoofers specs in which you would, simply put, be able to play a VERY limited range of notes and be able to achieve a greater level of sound pressure than you would in a typical application. Music would sound horrible and with the lack of cone control on music as opposed to the tones that it was developed for, it would suffer form mechanical failure quite easily...

What music do you listen to? Are you looking to play any chopped and screwed/ LOW music? Are you looking to compete?

If you can answer a few questions I wouldn't mind getting some box dimensions for you.

And for a first box of the sort, I would recommend a regular slot port made from the mdf itself. Those design plans implement the use of round ports. (pvc, aero)

AleroB888 · 12-09-2010, 04:48 PM

Quote:

Originally Posted by Bigshot44

recommendations?

I've even used the commercial Johns Manville wall insulation for some projects, more user-friendly than the old type itchy pink fiberglass. Its mainly to damp out higher frequencies that reflect and bounce around inside the box, but if it's a subwoofer, most of that is filtered out anyway with a low-pass filter.

More important is that the box not flex, and have proper bracing. If you tap on the box, or rap it with a stick, hammer, etc. and it makes a ringing sound, that's not solid enough, and needs more bracing or damping.

An exception might be that if the box rings at a very low frequency, it can add to the output and even sound pleasant. In general, though, ringing is not desirable.

Bigshot44 · 12-09-2010, 05:59 PM

Quote:

Originally Posted by Cashdollar2009

If you can answer a few questions I wouldn't mind getting some box dimensions for you.

And for a first box of the sort, I would recommend a regular slot port made from the mdf itself. Those design plans implement the use of round ports. (pvc, aero)

Well i listen to mostly Rap, Hip Hop, CnS, and a bit of techno.
oh and some of that "Bass test" music ex. DJ Billy E.
and not sure what LOW music is exactly.

Ryan from Ohio · 12-09-2010, 07:16 PM

The misinformation runs deep on the previous page.

Afugy · 12-09-2010, 07:18 PM

Quote:

Originally Posted by Cashdollar2009

You're really dropping it into a competition setup and tuning to 55Hz? You do know that you should NOT play music through those boxes right?

Why? I'd really like to hear why a box tuned to 55hz should not play music!

Just forget about ALL of those misleading box diagrams. Just tell us what sub it is and the specs or do your own math http://www.carstereo.com/help/Articles.cfm and tell us what you come up with.

Afugy · 12-09-2010, 07:20 PM

Quote:

Originally Posted by Ryan from Ohio

The misinformation runs deep on the previous page.

What took you so long?

Cashdollar2009 · 12-09-2010, 09:33 PM

Quote:

Originally Posted by Afugy

Why? I'd really like to hear why a box tuned to 55hz should not play music!

Just forget about ALL of those misleading box diagrams. Just tell us what sub it is and the specs or do your own math http://www.carstereo.com/help/Articles.cfm and tell us what you come up with.

Okay I will re-word it. Bigshot44, you will not be happy with what your 55Hz box would do on music. Playing the music that you listed will be mostly peaking 20Hz below the tuning of your box. At 6.5ft^3 you will have little to no control over the cone of your subwoofer resulting in not only bottoming the driver out, but also more than likely leading to total mechanical failure.

"Burp" boxes sound horrible on music. (Trying to pick my words carefully so they don't continue to get picked apart, I am defining music as songs with basslines between 30-50 Hz. The reason why most people online hop on to get some quick audio advice and add some "booooooooom" to their trunks and leave.) They are a "burp" box for a reason.

Afugy · 12-09-2010, 10:21 PM

Nothing wrong with a box thats tuned to 55hz, as long as its tuned with a flat response. Really I don't like to knock a box until its properly metered, by smaart or even term.

Are you building a box so you can do comps or you just want to be loud?

The size of the box has nothing to do with it bottoming out.

Haven't you heard my car? Tuned to 40hz, sounds great to untrained ear but missing out on 60hz to 125hz sucks. Thinking that a 6.5" or a 6x9" will produce that range efficiently without allot of work is madding.

Just think how shity this song would be with out 60 to 125hz http://www.youtube.com/watch?v=auDv6cf2PBM.

And I hope Ryan corrects me on this but for some reason building a box that fires into a trunk should be NO bigger then half the air space in the trunk, because having your subs firing into the trunk turns the trunk into a 6th order bandpass.