wvuviv30

I am in the process of planning my act for an audio system for the 4runner.

I can't deceide if I want to run 2 10" with a 200 watts to each sub (400 total), OR 1 12" with 350 watts.

Here is an Example set-up
10"
2 10" Alpine Type-E (50-200 RMS, 600 MAX) with a Kenwood Excelon KAC-X521 (165 x2 @ 4ohms)

12"
1 12" Alpine Type-S DVC (50-300 watts RMS (150 watts per coil), 900 MAX) with a Alpine MRD-M301 (175 x1 @ 4ohms, 350 x1 @ 2ohms)

Both will run about the same for pricing. I am going to build the box my self and build it so its tucked out of the way.

This is also a factor, I listen to heavy metal: Hatebreed, Slayer, Fear Factory, and other stuff like that.

gn86r

id go with 2 10"s... i was contemplating the same thing. if your budget allows id go with the alpine type-r subs. ive seen them on ebay for a decent price.

DavidA

I am a firm believer that two slightly smaller drivers can push out as much air and have a faster recovery time. Thus producing a better punch. Just my opinion. In the old days, about 15 years ago I ran four 6" Peerless woofers, two to each channel. It was very nice and clean. To me you were pushing the same amount of air but with multiple drivers it was faster. You can look at the old Bose 901 home speakers, they had nothing but a large array of small speakers. Ahhhhhh.....those were interesting days in car stereo.

Memphis_Yota

hey i have two 10 inch memphis HPO's with 1100 RMS running to them and i love it, from my experience i would go with the 2 10s and run them in a sealed box and try to run as much power 2 them as possible to get those sealed 10s pumping, sealed boxs hit harder and have a better sound for more hardcore music that you like. ported are for deep bass like rap so it is not for you
cody

LBC994runner

go with the 2 -10's

JoKEpLaYeR

I feel the same way. The recovery time on multiple small subs feels faster than larger ones. I've seen some very nice combos of 2-4 8" JL Subs and 1 10" JL that all sounded great and hit when they needed too. I do like Alpine subs, never had a chance to own any yet.

PoBoy

Bigger air space bigger subs...you need 2 '10's AND 4 - 15's

But, if it's just 1 - 12 against 2-10's...2 -10's - they'll fill the space a bit more than the 12.

PLEASE look at other brands beside Alpine - the Bose of over priced car stereo IMOP. Subs and amps are a HUGE market. There are some really good brands out there that go unnoticed and are much cheaper as a result of wanting to get their name out.

wvuviv30

Reason I chose alpine subs, is that you can go to any online dealer and see the subs.

PoBoy: I was actually looking at getting a JL Audio, preferably the w3v2 series. I used to have the 12w3-D4, when it first came out. I would hit hard with about 300 watts going to it.

Here is my system plan: I am not sure if I want to run 1 10 or 2 10s, its mainly going to depend on my funds. I am going to go with a JL Audio with a Dual Voice Coil, I am going to wire it up so it is a 2 ohm sub on the inputs.

Head Unit: Alpine CDA-9830 or CDA-9831
Front Speakers:* Rockford Fosgate FNP2414 (4" Component, 50W rms)
Rear Speakers:* Rockford Fosgate FNP2614 (6.5" Component, 50W rms)
4 channel Amp: MTX Audio Thunder404 (50x4)
*I want the Front and Rear speakers to match in: brand, model, and power ratings. However, I have seen many people cut holes in the doors to put some 6.5's in it. all the components will be matching.*


Subs & Amp....
Option #1: 1 - 10" and Mono amp
Sub: JL Audio 10w3v2-D4 (300 RMS)
Amp: Alpine MRD-M301 - 350x1 @ 2 ohms

Option #2: 2 - 10" and 2 channel amp
Sub: JL Audio 10w3v2-D4 (300 RMS)
Amp: MTX Thunder502 or Rockford Fosgate Punch P5002 (both are 250x2 @ 2 ohms)

SuperRunner98

I've always felt that you're better off getting 1 higher end sub then 2 average subs. Then, if you want to upgrade you can add a 2nd sub and amp rather than have to dump both subs. Running 1 10" or 12" JL, Alpine type-R, Infinty Kappa Perfect, etc. with a mean amp is a good place to start. Check out ebay too if you haven't already; brand new stuff sells for about 5% over cost. Good luck and get rockin'.

COYOTA $x$

Were those set up as a band pass box ?

way back when saw/heard a bandpass pox that "boomed" (inside the shop, not in a car) and was full of 4 inch speakers (16-20, I forget), that was more a function of the box design though than the speakers.

Also interesting to note that you dont need 1000watts to pump the home stereo like a car stereo.


Ive found the same thing that 8"s and 10"s 'generally' do better for the music type you describe. Not all 8's and not all 10's are created equal (or 12's) so its not complete brush to paint with. Trust your ears and realize that the same speaker and speaker box in 2 different cars (or the showroom floor) will likely not sound the same to a discerning ear.

Maybe it still is but used to be that JL's big advantage isnt so much in the speaker itself as it is they know very well what their speakers limits and strong points and characteristics are. Trust thier installation guide.

Speaking of which, anyone doing Isobaric clamshell loading anymore ? (rhetorical question not a Thread-jack)

wvuviv30

Whats this??? explain, i have never heard something like this.

DavidA

I have not seen anyone do it since, was it Alpine or ??? can't remember who did the dual woofers facing each other then had a slot loading up through the rear deck of the car? I thought that was a neat innovation.

COYOTA $x$

kinda like that....

from what I remember, JL Audios first "big burst on the scene" was using their W5 series speakers doing the isobaric clamshell load, using two speakers, face to face, out of phase with each other to creat a push-pull configuration, with a sealed or ported box behind one (or even in a bandpass enclosure).



surprisingly they still have info on their site about it
http://www.jlaudio.com/tutorials/isobarik/clam.html

Theory being that using two drivers would cancel out the non linearities between the two, creating a uniform controlled sound. Sonic reasons more than anything. No dB gain.

I still have a pair of those old JL 15w5's that I slapped into a hometheatre setup in a clamshell config.


anybody else has old outta date JL speakers and needs specs for them, I found this repository of Data sheets on them. Extremembly valuable reference
http://www.ofgb.org/reference/Music/JL%20Audio/

vietfob714

i would say go with 2 10s... i wouldnt go with alpines though.. i've had 2 infinity kappa perfect 10s in my 4runner and they were super clean and loud. Then i went on to 2 15s... that was too loud and now i have 2 solo barics... not too bad but maybe i'll upgrade to 4 solo barics.

4-RUNNIN' FREAK

Go with the 2 10"s. And look into a passive radiator.
Here is one explanation of what it is. I have 2 10" inch subs for home theater that use a passive radiator. The bass is so intense, but if not done right can make it sound like crap.

JoKEpLaYeR

Just curious, do you have pictures of how you have 2 Solo Barics mounted? I've been interested in running one in the rear storage compartment area.


I've heard one 10" sound good when done right. It was a JL (don't remember model) with the right box and the right amp. It rocked in my friends benz. 2-10's might sound better in an open area though.

COYOTA $x$

""FROM THE NET"""

What is a "passive radiator"?

A passive radiator, or "drone", is quite simply a speaker without a magnet. Generic or home-built designs can simply be a woofer basket, cone, surround and spider with no magnet attached. Custom-built passive radiators deviate little from this model, typically only using a different cone consisting of a heavier material.


So what's that good for?

It just so happens that this seemingly useless arrangement behaves very similarly to a standard port, when it is placed in an enclosure, which also contains an actively powered driver. This offers several distinct advantages over a regular ported design in some circumstances.

Advantages

1. A passive radiator has the amazing ability to tune a box to almost any frequency while occupying virtually no space at all. Unlike a port, which could displace as much as 0.5 cubic feet of air space within a box, a PR will displace virtually nothing, because it is just a speaker without a motor.

2. Once you move beyond the design phase, a passive radiator is very simple. A ported box often requires extensive box design and more difficulty in construction, because large ports must be "wrapped" around the inside of the enclosure to fit. A passive radiator on the other hand can be modified with the proper weight, and then installation is as simple as cutting a second hole in the box and mounting it as you would a normal speaker.

3. A passive radiator will give you all the great benefits of porting your box in situations where a ported box is simply impractical. These tend to be situations where a powerful woofer is being used in a small enclosure, a great deal of port area is necessary to accommodate that woofer's large displacement, and you want to tune that box low! It is not uncommon these days to run a 15" woofer with 4 liters of air displacement in a 3 cubic foot enclosure with 40 square inches of port tuned to 25 Hz. That port would have to be roughly 50" long, would greatly complicate the box design and completely waste over a cubic foot of air space in the process. A pair of 15" passive radiators, each loaded with 975 grams of mass would accomplish the exact same thing, would be very simple to implement and would displace zero air volume. Not a bad deal.

Disadvantages

1. Passive radiators are much more costly then a standard ported box. They can range in price from $50 dollars to as much as $200 dollars each.

2. Passive radiators cannot be oriented vertically. If they are, the loose suspensions on most of these units, coupled with the high moving mass, will cause them to sag and will reduce their effectiveness. In a vehicle, they should mounted facing towards one side of the vehicle, or most ideally, facing the front or rear of the vehicle. Having them on a slight angle is acceptable.

3. The initial design process is a little more complicated, and design programs are harder to find.



Selecting a Passive Radiator

While it is possible to build your own PR's with old woofers or whatever, my best advice in this situation is to use units specifically designed as PR's, such as the units that Stryke offers. There are several things you need to look for when choosing a proper radiator.

Cone area - The cone area of a radiator is the determining factor for how much mass you will need to add to achieve a given tuning frequency. If you place two radiators, one with 400 sq cm of cone area and one with 800 sq cm of cone area in identical box volumes and you want to tune them to identical frequencies, the larger radiator will require twice the added mass to achieve the same tuning frequency. This may or may not be relevant, because it depends on how much mass the suspension of the radiator can safely handle before it rips itself apart. If you need to load a radiator with 1500 grams of mass to tune it to the desired frequency and it will only handle 1000 grams, and you can't/won't increase the enclosure volume or tuning frequency, your only choices are to either reduce the PR's diameter (thus reducing the mass needed to tune to that frequency) or attempt to find a different radiator which will handle that load. Cone area is also a critical factor in displacement, which will be covered shortly.

Xmax - This parameter simply tells you how far the cone can travel before reaching the limits of the suspension. This second parameter completes the critical "displacement" factor of a passive radiator. Unless peak-to-peak travel is specified by the manufacturer, assume that xmax is a one-way figure, and should be multiplied by two to get p-p xmax.

Displacement is the swept air volume that a PR will displace, according to its cone area and xmax. Depending on your setup, you will typical need to have a total passive radiator displacement equivalent to at least twice the linear displacement of the driver with which you are using them. The equation for PR displacement is identical to that of driver displacement.

Let's do an example, using an Adire Shiva 12" woofer.

Adire Shiva - Cone Area (Sd) = 481cm^2
Xmax(p-p) = 3.16 cm
Displacement = 481 * 3.16 / 1000
= 1520 / 1000 or 1.52 liters.

An appropriate radiator for the Shiva should have at least 3.0 liters of displacement.

Stryke 15" PR
Cone Area (Sd) = 830cm^2
Xmax(p-p) = 5.0 cm
Displacement = 830 * 5 / 1000
= 4150 / 1000 or 4.15 liters.

The Stryke 15" units are well over our minimum displacement, so they will work great.

You can get away with going slightly below this ratio if your tuning frequency is well below frequencies which you typically play, but should be a higher ratio if you play frequencies very close to the box tuning. You can increase displacement by either using multiple radiators or a larger diameter radiator (which will require more mass loading) or switching to a radiator with more xmax (which won't need extra mass).

Qms and Vas - These parameters don't have to be anything specific, except that they should be as high as possible. Keep in mind that you want the radiator to completely couple with the air mass inside the box, and not dissipate any energy by itself. A PR with a very stiff suspension (low Qms and Vas) will still operate, but will slightly hinder the function of the box. Our Stryke 15" radiator has a Qms as high as 75 a Vas of 978 liters (35 cubic feet)!


part 1

COYOTA $x$

part 2 ""FROM THE NET""


Designing a Passive Radiator Enclosure

There are two ways of going about this. The first way is to first design a standard ported box to fit your needs, and then extrapolate the necessary numbers to create a properly tuned PR enclosure. The second method is to use a box design program that has functions for designing a PR box. This is the more accurate way of doing things. I'll begin with the first (and more complicated) method.

Once you have a radiator selected that will handle the displacement of your woofer, you must start by generating a ported enclosure, which will work well for your woofer. Once you have the box volume and tuning frequency determined; you must calculate a port length for that tuning frequency, using the port area equal to your radiator's cone area.

Let's use the example of our Shiva again.

I crack open Unibox 4.01 and start to plot out a Shiva box. I decide that an enclosure of 84 liters (3.0 cubic feet) with a port tuning to 20 Hz creates a nice flat response. I calibrate the port diameter function until my program reads a port area of very close to 830 cm^2 (128.6"^2). I then check the port length field, which states 711.69 cm (280.2") to tune to 20 Hz. That is a huge port.

Next, we have to calculate the mass of the air, which is contained in this long port. This amount will be the mass we use on our passive radiator.

To do this, first we calculate the volume of air in that port.

Port Volume (cm^3) = port area (cm^2) * port length (cm) / 1,000,000 (convert to m^3)
830 * 711.69 / 1,000,000
590,703 /1,000,000
Which would equal 0.5907 m^3

Next we have to determine the mass of this volume in grams

Mass = "Port" Volume * Density of Air
0.5907 * 1.21
0.715 kg
Which would equal 715 grams
There you have it.



Now, what the heck does all that mean?

Well, with these equations, we've basically calculated the mass we need to load our 15" radiator with to tune our 3 cubic foot Shiva box to 20 Hz!

This leads me into the second method of designing passive radiator boxes, which is to use design software. To date, the only box software I know of which will actually do this is Unibox 4.01, which is a free Excel spreadsheet. An excellent program; Unibox has a field for punching in the T/S specs of your woofer. You can then scroll down to the passive radiator section, where it allows you to punch in the specs for your radiator and adjust box volume and radiator mass, along with a couple of other things. All of the box plots in this article were done with Unibox, and the screen shots are also of that program.

So now I will punch this information into the passive radiator design portion of Unibox, and see if the results are consistent. For simplicity sake, I am going to use the standard issue 700 gram Stryke radiator. The 15 gram difference is too small to make any difference.

As you will see, the results line up very closely!


The tuning on the ported box was 20 Hz, verses the tuning on the passive radiator box of 21.16 Hz.

The F3 of the ported was 25.4 Hz, verses 24.81 Hz for the PR box. The box peaks were also nearly identical.

Why the discrepancy?

Well, the slight changes are due to the loss factors I mentioned before. The PR is not coupling 100% with the air, causing some dissipation of energy through the suspension. The effect is negligible with most PR's, but just for information, a lower Q will result in a higher enclosure F3, because of the increased damping ability. The effect is identical to woofers with very low Q factors, exhibiting a loss in low frequency output because they are "over dampened"

Custom Weighting

Sometimes, a design will require you to add custom mass yourself. These situations are usually rare, because most companies will custom mass their PR's for you. However, it might actually be beneficial for you to order a generic model, and then custom mass it yourself. This will let you tweak the tuning by ear.

This is a fairly straight forward process which requires securely fastening weights to the cone of the radiator, to increase its moving mass. You can use any type of weight you want as long as it is securely fastened. You can use, marbles, ball bearings, washers, bolts, and spare change, whatever. Just get out a small cooking scale, or whatever, and find out how much these parts actually weigh. I definitely recommend placing this mass in the "voice coil" of the radiator. You can use a mixture of solid objects as shear mass such as epoxy, wax, hot melt glue, plaster, or any other material to pour into the cavity to hold those pieces in place. Remember that your adhesive also has mass, so you'll have to measure that out as well. If you have to, you can attach flat objects to the back of the cone with epoxy or hot glue; just make sure you distribute the weight evenly over the cone area. You can also use dabs of hot melt glue or two sided tape to fasten weights to the radiator for tweaking the tuning frequency.

Additional Information

There are a few small differences between PR and ported boxes, but nothing significant. The frequency response of a PR box will have a notch, or dip in frequency response, at the resonance frequency of the passive radiator. Because the Fs of most radiators is pretty low after the added mass (below 10 Hz), this notch is very rarely a problem. Response below Fb may roll off a little steeper if the resonance frequency of the radiator is nearby. If not, they should be pretty much the same.

It's very important that PR's never be mounted horizontally, (face up or down), especially in a vehicle. Not only will the suspension sag over time, but the radiators will also move on their own whenever your car goes over bumps. This could potentially damage the radiator and the woofer, and might even increase inter- harmonic distortion.

I don't encourage you to use a PR in necessarily every situation. They are most effective (by far) when you want a small enclosure with a low tuning frequency and with enough port displacement to accommodate a high excursion woofer. Sometimes, it's just easier to use a port.

Summary

I hope you found this interesting,and informative. Whether it persuades you to try one of these designs in the future, or just increases your general knowledge, either way you now have the inside edge on Passive Radiators.

COYOTA $x$

along a similar thought plane.....

You also have a-periodic chamber setups: USD used these quite a bit in the 90's including their acclaimed Grand National (which is sitting in a storage garage somewhere on the lower east coast, according to the net)

AP Mats

----AP enclosures mount like Infinite baffle systems.
----You must seal the front of the enclosure into the interior of the vehicle.


http://www.usdaudio.com/products/ap.php

An AP subwoofer system is one which employs 2 enclosure volumes coupled with a purely resistive element, the AP Mat. When such a system is properly designed, it is possible to control the woofer cone movement by the energy transfer though the precision acoustic resistance of the AP Mat. The completed system will be considered A-periodic, or over-damped with a Q well below 0.7 Qts. In contrast, most car audio systems are grossly under damped, with Q's greater than 0.8 and higher. These high-Q systems have poor transient response, nasty peaks in their frequency response and high rates of roll-off. The result of controlling cone motion with a resistive AP Mat is a very low system Qt. A-periodic systems feature excellent transient and phase response, smooth frequency response and extended very-low frequency reproduction with quicker attack, less bass hangover and lower cone distortion.

Constructed of high-quality MDF and special high-density FMSTM damping material
Regains trunk space by using a very small box size (less than 0.33 cubic feet)
No expensive meters needed to "tune" the enclosure
Very predicatable flat frequency response
Power handling of small sealed box w/ bass of a large box.
Provides detailed bass response, and lower distortion.
Improved transient response versus other boxes designs.
AP Mat enclosures extend lower than conventional enclosures.
Comes with easy to follow installation instructions.
Available for 10", 12" and 15" subwoofers
Subwoofer Compatibility
10" Subwoofer Qts of 0.39 or less
12" Subwoofer Qts of 0.45 or less
15" Subwoofer Qts of 0.45 or less

Greg_Canada

I'm running an MTX sub and amp.. 12" in a ported box... sounds pretty good and the remote gain control is awesome to have, cause if you want to listen to GNR you turn it down and crank the volume, or you want to listen to some sublime or whatever, pump it up to max... best of both worlds really (for me)... until i can afford some L7 solobarics (in a few years)...