Nice little puzzle

 

Eric N
Unregistered guest
i have 2 adire shivas and with 600 watts RMS they are run best in 1.5cuft per sub but i dont have that much room to run them. i have a 2004 dodge ram 2500 and i wanna run both of them in this box
http://musicmooseaudio.com/dodge_quad_cab_truck_d03.html

it only has .57 cuft per sub. i have a JBL 600.1 but i know this isnt going to run them both hard enough to hit xmax, how many whatts and i going to need to get them both to hit xmax?
 

Bronze Member
Username: Suicideshifter

Bristolville, Ohio United States

Post Number: 86
Registered: Jul-04
anybody?
 

Silver Member
Username: Mixneffect

Orangevale, Ca. USA

Post Number: 456
Registered: Apr-05
If a driver requires 1.5 cf in a sealed enclosure, you may get away with deviating about 10% either smaller or larger. But, if you deviate 66% it will raise the FO and sound like crapp.

A 66% smaller sealed enclosure would not sound good, or achieve better linnear travel, no matter how much power you give it.

I would rather consider a ported enclosure if your driver is suited for it. Ported enclosures are generally smaller than sealed by about 40-60%, depending on the driver QTS.
 

Silver Member
Username: Redskin

LondonEngland

Post Number: 190
Registered: Dec-03
"Ported enclosures are generally smaller than sealed by about 40-60%, depending on the driver QTS"

That'll be a first then.
 

Silver Member
Username: Rob_preg

Royal oak, Michigan United states

Post Number: 115
Registered: Sep-05
um....i was under the impression ported were larger than sealed....is it just me?
 

Silver Member
Username: Iufan4lifeul

Post Number: 651
Registered: May-05
generally ported are much bigger than sealed. I think you might have mispoken mixneffect?
 

Bronze Member
Username: Suicideshifter

Bristolville, Ohio United States

Post Number: 89
Registered: Jul-04
well then...does anyone have any advice on how i should run these shivas in this small of an enclosure?
 

Bronze Member
Username: Suicideshifter

Bristolville, Ohio United States

Post Number: 90
Registered: Jul-04
...if the shivas wont work does anyone know of any good subs that would perform great in a .57cuft per sub?
 

New member
Username: Suphahighfly

Post Number: 4
Registered: Oct-05
The box that was shown is designed for the SWS subs that mount at only 3 1/4 in. You might want to look at thoses they are a little pricey but will save you the space.
 

Silver Member
Username: Mixneffect

Orangevale, Ca. USA

Post Number: 457
Registered: Apr-05
Please read carefully

"Ported enclosures are generally smaller than sealed by about 40-60%, DEPENDING ON THE DRIVER QTS"

The driver QTS is what determines what type of enclosure is better suited for a given speaker.

It has been proven that drivers with a QTS of up to 35 would be better suited in a ported enclosure.

It has been proven that drivers with a QTS of 40 or higher would be better suited in a sealed enclosure.

It has been proven that drivers with QTS between 35-40 would be suited in either type.

Some would preffer to go sealed only on drivers with a QTS above 50, but that is just a prefference, and definetly not a scientific fact.
 

Silver Member
Username: Redskin

LondonEngland

Post Number: 197
Registered: Dec-03
Driver qts is irrelevant, a sealed enclosure for any speaker will be smaller than ported enclosure for the same speaker.
 

Silver Member
Username: Mixneffect

Orangevale, Ca. USA

Post Number: 458
Registered: Apr-05
For the record;

Let me explain. Sealed boxes require a much larger box compared to a ported box, due to the fact that a ported box produces a lower frequency cutoff than a sealed box. Thus a sealed box requires a larger box than a ported box when you try to get the same FO.

In other words; comparing apples to apples.

It doesn't matter if a manufacturer recommends their driver to be used in a sealed box in a much smaller enclosure compared to a ported enclosure if the FO is off by 20-40 Hz.

The main reason for an enclosure is to allow the driver to reproduce larger wavelengths. A sealed box is limited to how large of a wavelength it can reproduce. A ported box will reproduce the same wavelength using a smaller box.

Some drivers will not reproduce the same wavelength in a sealed box compared to a ported box, no matter how big you make the sealed box.

So, to make a better comparison; let's make the ported box small enough so that it has the same FO as a sealed box. Now compare the volumes.

Red = Sealed
Yellow = ported
Blue = ported undersized to match sealed FO

Upload
Upload
Upload
Upload
 

Gold Member
Username: Southernrebel

Monroe, Louisiana USA

Post Number: 1467
Registered: Mar-04
hey mixneffect,

where did you get bassbox pro 6? :-)
 

Silver Member
Username: Mixneffect

Orangevale, Ca. USA

Post Number: 460
Registered: Apr-05
Sealed;
VB=1.32 cubic foot
QTC=.707
QL=6.934
F3=45.91 Hz

Ported;
VB=3.125 cubic foot
FB=21.91 Hz
QL=6.934
F3=25.36 Hz

Ported to match Sealed FO;
VB= .668 cubic foot
FB=21.91 Hz
QL=6.934
F3=45.91 Hz




Sealed using the MUSIC MOOSE ENCLOSURE
VB= .57 cubic foot
QTC=.959
QL=6.934
F3=51.9 Hz

Upload

Red=optimum sealed
White=Music Moose .57 cf box

So Eric N;

You may use the Music Moose box, but you will only get down to 51.9 Hz
 

Silver Member
Username: Mixneffect

Orangevale, Ca. USA

Post Number: 462
Registered: Apr-05
http://www.madisound.com/new.html
 

Silver Member
Username: Redskin

LondonEngland

Post Number: 198
Registered: Dec-03
Ok so we're disregarding what the speaker will actually sound lke after you've shrunk your ported deign by 75%. So going by your graphs which I'm having difficulty reading the sealed box is 37liters and your shrunken ported is 19liters tuned to 22hz. Obviously we now need to add the volume taken by the port to get the overall box size. So lets use a 4" port for starters. Using that to tune 19liters to 22hz gives 21liters of port volume added to the 19liters we already have makes 40 liters. Which is smaller again?
 

Silver Member
Username: Mixneffect

Orangevale, Ca. USA

Post Number: 463
Registered: Apr-05
Redskin let me appologize if I have somehow offended you. Please forgive me.

I am just trying to help Eric N.

By the way. I am not going to get into the nitty gritty about this. I am not going to subtract and add for driver, port, speaker wire, terminal cups, etc... for displacement. Give me a break man.

I just gave proof of what I was advising.

By the way, the tunning frequency makes hardly any significant change in box size (FB 22Hz or FB 33Hz), and a 4" diameter port would be too long for that box.
 

Bronze Member
Username: Suicideshifter

Bristolville, Ohio United States

Post Number: 92
Registered: Jul-04
Mixneffect, how many watts should i run to them to drive them to full xmax? and u say that i'll only get down to 51.9 Hz...does that mean it's not going to slam as hard in this box?
 

Bronze Member
Username: Suicideshifter

Bristolville, Ohio United States

Post Number: 93
Registered: Jul-04
and also, does anyone know any subs that perform better than my shivas in this small of a box? by them way, im Eric N, thanks for the help mixneffect
 

New member
Username: Gezyon

Havelock, NC United States

Post Number: 3
Registered: Nov-05
I have heard that the Kicker Comp CVR's do really well in small enclousers and that is what they had prefered for me to use in my 2005 Dodge Daytona, and it hits HARD! They sound really good, I dont know if you want to go with them, but they are nice, and sound good.
 

Silver Member
Username: Mixneffect

Orangevale, Ca. USA

Post Number: 468
Registered: Apr-05
Run them at full power. Whatever RMS is. i am at work now and dont have all the programs or websites saved in my favorites so ...

An FO of 52 Hz doesnt mean it will not hit hard or not. It just means that it will not reproduce the lows.

60 Hz is ok for bass. 40 Hz is verry verry good. 30 Hz is exceptional. 20 Hz is almost hard to find.

You are at 52Hz. This means that in that particular box it will reproduce 52 Hz at 3 dB below par. You will still be able to hear 40 Hz, just not as loud.
 

Silver Member
Username: Redskin

LondonEngland

Post Number: 201
Registered: Dec-03
I not offended or anything else!I'm just a misarable git. But you haven't proved a ported box is smaller than a sealed. Ignoring port displacement on a box that small is daft. The port will take up the same space again as the box. 4" port was just an example of how much volume a port takes up if you swapped to a slot port then even more space is required by the port. Going from a 22hz to a 33hz tune will save 0.4cuft in port volume. I would of thought that was a big difference. I'm curious has anyone actually built a seriously undersized low tuned ported box?
 

Bronze Member
Username: Mikegrab21

Post Number: 13
Registered: Oct-05
How come everyone recomends larger ported boxes if they sound worse larger? This is unconsistent with your graphs....but maybe the world is wrong?
 

Silver Member
Username: Mixneffect

Orangevale, Ca. USA

Post Number: 469
Registered: Apr-05
Michael;

Car audio drivers are usually designed with a high Qts. This is to allow them to be used in sealed enclosures or infinite baffles. These types of drivers are usually more powerfull/robust compared to home audio drivers. Some better SQ car audio drivers are now designed with lower Qts, so it is becoming more common nowadays. Never-the-less, look into what Qts does and/or is used for.

Eric, I have a better graph for your setup. I just couldn't post it last night due to technical difficulties. If you like your drivers, and wanna use that box, it wont be a problem. It will not reproduce below 40 Hz, thats all.
 

Bronze Member
Username: Suicideshifter

Bristolville, Ohio United States

Post Number: 95
Registered: Jul-04
ok thanks mixneffect. thanks for all the help, im going to go ahead and use them. anyways, if i dont like the way they sound, i'll just get different ones, thanks again
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