# 8" 'subwoofer' for free air use...suggestions



## mvw2 (Oct 2, 2005)

I'm working out my car install, and I'm wanting to get rid of my current sub and run something built into the rear hatch. I'm currently thinking 8" woofers due to limited size.

Now, I like my TC2+ but I want to head a different route. I'd like to regain trunk space and provide a solution that can fit into the rear hatch and be able to run free air(deadened, open to 'outside'). 

I had a lengthy discussion with an individual about speakers, T/S specs, subs, and how everything works together to create an end result. Basically, in a free air application, VAS and Fs are the determining factors for low end response(using smaller woofers to do subwoofer duty), high VAS, low Fs. 

Looking around for 8" woofers with the highest VAS and lowest Fs, a few stand out. One is Usher's 8955A 8" woofer,
http://www.partsexpress.com/pe/showdetl.cfm?&DID=7&Partnumber=296-618
A couple others are Seas paper and aluminum 8" woofers, the CA22RNX and L22RNX,
http://www.madisound.com/cgi-bin/index.cgi?cart_id=4540230.26142&pid=1944
http://www.madisound.com/cgi-bin/index.cgi?cart_id=4540230.26142&pid=2068

Neither are really supprising as Seas is pretty famous here for good low end authority and I've known Usher seems to offer some of the bassier options on Partsexpress(for the given size driver). The Scanspeaker Revolator is obviously a good option too, but $$$.

Anybody else have any suggestions? Basically, I'm wondering if I can get a couple/few 8" low frequency geared woofers to achieve subwoofer duty...without the need for a box. I'm trying to achieve a usable frequency range of 40-80Hz. I am prepaired to provide some EQing to this to improve bottom end response, but I do need a woofer that's really geared for low end performance and is also usable in free air(although power input can control excursion limits).

Anywho, I'm just trying to see if there's any other options that may be available to me. I understand there are larger, shallow mount subs, but I don't know if I can offer even enough space for a 10" woofer. I still need to break out the tape measure to see what exactly I have to work with, but I am vertically limited.


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## chuyler1 (Apr 10, 2006)

The Image Dynamics ID8v3 is always an option...


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## NaamanF (Jan 18, 2006)

I tried a pair of ID8s IB. Not so good. They also had some really bad noise. Wasn't sure if it was the plastic they used to cover the magnet or something else. The two I had made the same noise.


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## |Tch0rT| (May 7, 2005)

I'm going to attempt to use four 8" Ascendant Audio Assassin subs IB soon. I hope they do well. heh

Ryan


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## sqkev (Mar 7, 2005)

going with a 10" will open lots more options, 

One more thing, the fs of the driver doesn't have to be extremely low, anything from 25hz-35hz would be fine. In my application, I have to set the subsonic filter at 25-30hz since the lowend without is too extreme/exaggerated. With the filter on, the music is more natural. This is due to the gain in the cabin.


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## thadman (Mar 1, 2006)

Vas only determines box size

A driver with the same Qts and Fs will perform the same regardless of the Vas, so I wouldnt really bother yourself with looking for one with the highest Vas.

lowest Fs and highest Qts drivers are *best* suited for IB, but almost all drivers are applicable


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## mvw2 (Oct 2, 2005)

Talked more about T/S with a guy over on CAF. He was emphasizing looking at a higher QES and low CMS for good control in a free air application. Vas and Cms was less important as long as Qes was high and had enough Xmax to force it low and loud. Basically, enough power and excursion, I could get the output I want(more than one driver of course). I think his initial talk on VAS/Fs was because I was talking a lot about lower frequency response. Still, the above drivers seem like good choices, and the CA22RNX seems to be the best option in terms of QES. Also, Vas and Fs is good too, compared to the ranges I've seen so far.

One woofer the individual suggested was Audioque's SD2 8" sub. However, I have yet to decide how much power I want to give this new sub format. It obviously is built for sub duty and has the throw for shear output, but the high mounting depth and high power requirements leave me thinking I don't want to head that route.

I'll have to do some measuring and yank off the rear hatch panel to see what I could truely fit. I'm currently assuming anything deeper than 3-4" will start to require a pretty thick baffle to get rear end room. As well, the size of this area is limited vertically. The Forester has a pretty low rear window, and I'm not quite sure how easy 10" woofers will fit. My initial inquiries are into 8"s for now, and if I can fit 10"s, I'm still looking at something relatively shallow(normal woofer kind of shallow) and something that doesn't need a ton of power, think around 500w total, probably a bit less. I don't need high output, only enough to blend and fill with the fronts. A wagon really makes this easy as I'm not fighting through the trunk.


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## Infinity (Jun 28, 2005)

You must've spoken to bassman. Have you noticed that AQ and DD are the only recommendations the guy makes? I think he get's a kickback, or at least he has a serious brand hard-on.


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## Cancerkazoo (Jul 21, 2006)

I've read a QTS between .6 and .7 is the best for IB, with a FS <30hz. also if you get a DVC woofer Adire has an article on how to adjust the QTS with a variable resistor on the 2nd VC, altough you can only raise it. I plan on trying that in my IB install when I get my car.


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## GMo (Aug 9, 2005)

^^ I agree with cancerkazoo.

The Qes/Qts spec you should look at should be around what you want for the final Q. In an IB application, Q is basically unaffected as the IB space compliance doesn't significantly affect the woofer.

You should look for a driver with a high Xmax and low Fs.

Cms should be lower, but I wouldn't select my sub on this spec. Cms is proportional to Vas.


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## Cancerkazoo (Jul 21, 2006)

variable QTS "RDO" by Adire audio.....found the link


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## mvw2 (Oct 2, 2005)

Yeah, talking to Bassfreak for the last few days. Basically, high QES for power and control, low Fs and Xmax for capable output. So far, the CA22RNX seems to be the best choice so far. Still looking...


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## mvw2 (Oct 2, 2005)

One to add, Earthquake SWS-8, can't really find much for T/S specs though.


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## GMo (Aug 9, 2005)

mvw2 said:


> Yeah, talking to Bassfreak for the last few days. Basically, high QES for power and control, low Fs and Xmax for capable output. So far, the CA22RNX seems to be the best choice so far. Still looking...


High Qes = lower damping = less "control"
Power isn't directly proportional to Qes.

I think the CA22RNX would be a decent choice.


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## mvw2 (Oct 2, 2005)

Yeah, I don't get that, but it's apparently desired to have a higher QES. I only understand it as having more or less power to control the cone in a "the motor is more or less overwhelming" sort of way.


Kind of have another one to add, but I don't quite think it offers as good a solution as others I've mentioned, Hi-Vi's D8G woofer, upper .5 QES, pretty high Xmax, but needs more power and Fs is a little higher/Vas a bit lower.

So far, the Seas seems to be the most capable choice sort of an actual subwoofer.


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## mvw2 (Oct 2, 2005)

Rear hatch pics, not a lot of depth but spots here and there allow straight through to the outside skin. Top to bottom is about 10.5" or so. 8"s seem plenty doable. 10"s may be able to fit but would be a tight squeeze. Plus depth is of some concern.

This is what I'm working with.


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## w00tah (Feb 5, 2006)

Pair of Mpyre's 65x's maybe? They look kinda like something that might be worth considering....


Kef


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## mvw2 (Oct 2, 2005)

Yeah, I was thinking about some 6.5" "mini-sub" options as well. I'm just not sure how far I want to step down in cone area. For midbass, the Extremis/Mypre 65x is a very viable option. My bro uses a pair ED's EU-700 6.5" mini subs in his car as a subwoofer substitute, and they don't do half bad filling in the lower spectrum, more than you'd assume a 6.5" driver would. As well, JL and Tang Band offers small options too. There's even 8" subs available from a large variety of manufacturers. However, it comes down to a matter of power usage, mounting depth, and cost.

Modeling up the Mpyre in BassBox, I do get a small gain in low end extention, but I lose a TON of output. The Seas at 80w is still a good 8dB higher even if I feed the Mpyre 150w. SPL is one thing I need to be able to generate to make this system work well. Whatever I run will have to be able to keep up with whatever front setup I run.

I may start looking at 10" woofers too, but if I go that route, I can forget about any form of recessed mounting and am really pushing up to the top and bottom edges of my workable area. Still, I do see the gains of moving up in woofer size. I just know 8"s wouldn't be a pain to work with.


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## chuyler1 (Apr 10, 2006)

For some reason I thought we were talking about installing subs in a sedan. 

A hatch-gate is a different story. This is more along the lines of a small sealed enclosure...if you do it right. Add several layers of sound deadening to all of the metal parts, install a baffle, and seal the inside of the gate from the rest of the car. Then you have a sealed enclosure.


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## npdang (Jul 29, 2005)

Vas, Qts, and Fs do determine the lower end sensitivity and rolloff of the driver. But the transfer function of your car door/interior is also equally important, if not more so. It's been my experience that even low qts drivers of ~.3 and low fs ~ 40hz can yield a flat response down to 30hz in most doors.

The most critical parameters imo should be price and xmax/xmech.


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## NaamanF (Jan 18, 2006)

I try not to say bad things but as far as the Mpyre 65X....don't. If you really feel the need, I have one I can send you to try.


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## npdang (Jul 29, 2005)

NaamanF said:


> I try not to say bad things but as far as the Mpyre 65X....don't. If you really feel the need, I have one I can send you to try.


 I've noticed alot of high excursion 7" woofers having very limited suspension throw. Is that the case here as well?


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## NaamanF (Jan 18, 2006)

I not sure what it is, but it does seem to have limited throw/excursion. It doesn't take much to get it the reach it's max throw and when it does it's not pretty. I really doubt the claims they make but then again I could be wrong. Wan't to try it out?


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## npdang (Jul 29, 2005)

NaamanF said:


> I not sure what it is, but it does seem to have limited throw/excursion. It doesn't take much to get it the reach it's max throw and when it does it's not pretty. I really doubt the claims they make but then again I could be wrong. Wan't to try it out?


 Sure would love to. I've noticed alot of high excursion mid/bass may have the bl to reach their rated xmax values, but not the suspension throw. They're also very noisy with alot of lead slap and air turbulence.


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## Beau (Oct 8, 2005)

Have you looked at the DAYTON QT210-4 8" QUATRO SERIES SUBWOOFER?


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## mvw2 (Oct 2, 2005)

The hard part is not really knowing what I should be looking for. I was gearing towards the high Qes as it suits IB use and high Vas, low Fs for low end response. I'm not sure what kind of problem would arise with a lower Qes. I'm not sure how more power is a problem other than the fact that you may more easily bottom out the driver. That could easy be solved by limiting power. Still, I kind of want to still lean towards the high Vas, low Fs as it would be easier for me to get low end output out of the driver. It doesn't help if the woofer rolls off really early, and I have to work to get that lower end respose. 

I do need to see what true 8" subs I have available, but I know I'm going to have a hard time finding something shallow and decently sensitive to not need a ton of power. All I need is some number of woofers that will be able to handle the lower frequencies with relative ease and output enough sound pressure to match the front stage. As far as excursion, that will primarily determine how many drivers I may end up with. 2 real 8" subs could output as much as 3 or 4 low frequency oriented midbass woofers. It comes down to a matter of how hard it would be to mount these drivers, how much power I'll need in the end, and the total cost of the needed hardware. Whatever combination works best will be the optimum choice. True subs with a lot of excursion would just allow me to run fewer drivers, but if 4 woofers with less cost can fit and run lower better, I see it as a better option. 

It won't really be a sealed enclosure. It _is_ in the hatch, but I don't plan on sealing anything off. Basically the baffle and interior paneling will be deadened, but the rear end of the woofers will be open to the outside. I don't think I could get any type of low end response with so little room if sealed. As well, in something that small, I'm probably looking at needing a lot more power, again something I don't want to do.

Design constraints:
Max woofer size: 8-9"
Max # of woofers: 4
Max mounting depth: 4"
Max total wattage: 500 watts rms
Frequency operating range: 40-80Hz

The end goal is to have a system that can match SPL output of the front stage in that 40-80Hz frequency range. It is mearly to blend and fill.

Front stage:
Tweeter: ScanSpeak D2904/6000(Alpine F#1 version)
Woofer: not quite sure yet...have been leaning towards Seas P or CA18RNX...

This just gives an idea of where I'd like to sit for this design.


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## DS-21 (Apr 16, 2005)

Madisound has the Peerless SLS8 back in stock. That's my pick. I don't think there's a better all-around compromise woofer for I-B installs than it. (I use a pair in my doors.)

And if you buy something from a car-fi company (Image Dynamics et al.) you're not going to get within a light-year of the performance for the double the money...


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## DonutHands (Jan 27, 2006)

what is the volume of the hatch panel area, it really does not look all that big. it looks like you would have a medium sized sealed enclosure on your hands if you do in fact seal that area up somehow. so you may find yourself looking for drivers that work in a sealed enclosure.

what is that 10" sub that has the reverse mounted neo magnet? I think that would work best if that hatch was sealed up.


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## Cancerkazoo (Jul 21, 2006)

internecine said:


> what is the volume of the hatch panel area, it really does not look all that big. it looks like you would have a medium sized sealed enclosure on your hands if you do in fact seal that area up somehow. so you may find yourself looking for drivers that work in a sealed enclosure.
> 
> what is that 10" sub that has the reverse mounted neo magnet? I think that would work best if that hatch was sealed up.


Are you thinking Illusion Audio? Here is an 8" I have.


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## DonutHands (Jan 27, 2006)

yup, thats the sepaker i was thinking of. make the hatch panel sealed and throw a 10 in there, done.


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## dBassHz (Nov 2, 2005)

Hey DS-21 have you compaired the Dayton RS225 to the SLS. I am still trying to decide on a dedicated midbass (50-160Hz)


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## DS-21 (Apr 16, 2005)

omarmipi said:


> Hey DS-21 have you compaired the Dayton RS225 to the SLS. I am still trying to decide on a dedicated midbass (50-160Hz)


I have not compared them directly. However, in that range the SLS will give you a lot more output, as it has a good 2mm xmax on the Dayton. Basically if you want more output with less EQ requirement go with the SLS, if you want more flexibility (can play much higher), lower cost, or are a cast-frame fundamentalist (the SLS's stamped frame is the nicest such one I've seen, and uniquely for a stamped steel frame features vents under the spider as well) and don't mind needing to EQ your midbasses to get their low-end response up, then go with the Dayton.

You're also much less likely to dent the SLS's cone.


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## mvw2 (Oct 2, 2005)

Adding a new one:
Tang Band 8"x12" subwoofer
http://www.partsexpress.com/pe/pshowdetl.cfm?&DID=7&Partnumber=264-838

89dB Sensitivity, 4 ohm, 90w rms, 12mm Xmax

Using BassBox and comparing against the Seas 8" woofer, output's quite close per wattage, just a little peaky right above 100Hz and drops off a dB or two down in the desired frequency range. Still, the 12mm Xmax may make up for that  Interesting choice non-the-less. ...can't believe I didn't think of oval woofers...


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## chuyler1 (Apr 10, 2006)

mvw2 said:


> Adding a new one:
> Tang Band 8"x12" subwoofer
> http://www.partsexpress.com/pe/pshowdetl.cfm?&DID=7&Partnumber=264-838
> 
> 89dB Sensitivity, 4 ohm, 90w rms, 12mm Xmax


I wonder if you could get those to fit under the rear deck where 6x9s would normally go.


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## mvw2 (Oct 2, 2005)

Remember wagon, no rear deck. However, I did mention them to someone looking into a sedan install. Being only 8.5" wide, I'd think you'd be able to fit a couple strapped to the underside of the rear deck of most sedans. Bolt on an MDF baffle across the underside of the rear deck, have holes cut out for air flow/cone extention, and bolt the subs on from the trunk side. A pretty simple solution I'd think.


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## chuyler1 (Apr 10, 2006)

Sorry, I was just running ideas through my head. I guess if you have room for 8"s but you really want 12"s, it would be a good compromise.


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## mvw2 (Oct 2, 2005)

The only downside for my install is the mounting depth of near 6". Still, this seems like the most capable choice within my design constraints and mounting depth isn't my greatest constraint. As well, I do have a few areas that allow pass-through to the outter door skin, allowing some available depth as long as I can line up the driver appropriately. I'll have to break out the tape measure and see if I can even position them over the open areas. Otherwise, I'd need a thicker, heavier, and increasingly protruding baffle, not quite a desired route.


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## niceguy (Mar 12, 2006)

Not to threadjack you but TB also has 6x9 subs along w/the 8x12s...I know you don't have a rear deck but since you threw them out there...


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## mvw2 (Oct 2, 2005)

I am fully aware of the 6x9s, however, they aren't capble enough to compete with other options like the Seas for low end performance and output. The Seas offers a better low frequency drop off and a lot better sensitivity(6dB). With the 6x9 Tang Band, I don't really get any more cone area or excursion, so the Seas still beats it.

The Tang Band 8"x12" on the other hand looks like a little beast of a woofer. Oddly, output is earily familar to my TC2+ when modeled in the same box(sealed or ported) using BassBox, only about a dB or two off of each other through the entire curve. 1.1 liters of volume displacement(Xmax*Sd*2) isn't half bad either. I think my TC2+ is around 1.7 liters.


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## Guest (Aug 12, 2006)

I don't know if there is any type of phobia or backlash here about using "mass market" brands (with enormous R&D capacity), but these JBL's http://manuals.harman.com/JBL/CAR/Boxes and Parameters/GTO 804D.pdf would spank the pants of the SEAS (a brand which I like - I own W22's among others) as subwoofers (as opposed to midbasses) - which is what I _think_ you are looking for. You seem to have the right amount of depth/enclosure volume for them to function quite well. I know they are not as "sexy" as the Seas, but with 11.5mm of xmax, they should provide plenty of oomph - without bottoming or an IMD bonanza.
This place has some crazy low prices on JBL http://www.ikesound.com/category-category_id/122 but don't seem to list the 8. I'd give them a call if you were interested in the 804. Good luck.

cheers,

AJ


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## mvw2 (Oct 2, 2005)

I have nothing against mass market equipment. I'm quite open to anything and everything. All I ask is that it can perform the duty I have set for the driver.

Modeling it up, the frequency drop off is very comparable to the other choices(how quickly it drops off), but output per watt is about 8dB low. This of course is purely an issue of available power and how much I'm willing to provide.

As well, there's the matter of air flow, how much volume it can push. The less one driver can move, the more drivers I need to create the needed net volume capability. The GTO woofer is mighy capable, more so than the Seas in pure output. However, it doesn't compare to the Tang Band option at nearly half. So, I would pretty much need two GTO 8" woofers to match one TB 8"x12" woofer. As well, I'd have to run it off more power to get the same SPL. 

TB's 8" sub would be very similar to the GTO 8", similar cone area, similar Xmax, and similar SPL at the desired working frequency range.

The limitation with the Seas is the limited Xmax. The sensitivity is there, much more so than my other choices, but shear output isn't. In that reguard, yes, the GTO would basically spank the Seas, but...TB offers a very similar option as well as a more SPL capable option in their 8"x12" version that is still able to fit within my size constraints.


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## Guest (Aug 14, 2006)

If you can fit the TB's that might be the way to go. They definately will move more air than the JBL 8's (or 10's).
SQ wise, I've been less than impressed with the 8" TB's I own (never heard the 8x12's). Whereas they have plenty output, their higher distortion levels (than the JBL's for example) can easily be heard playing test tones. As well as music.
So I guess it all depends on what type of balance you want to strike between sound quantity and sound quality, not to say that you can't get both from the 8x12. Never heard it. Those impedance wiggles in the smoothened TB graphs (cone modes) would worry me slightly. Can't be good distortion wise.

cheers,

AJ


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## mvw2 (Oct 2, 2005)

Yeah, it's tough to say. Outputwise, I may use very little. Currently, I hardly use my sub to any decent extent, mearly to blend and fill, not BOOM. In this reguard, two normal 8"s may be more than enough. As well, one 8"x12" may be enough. Two under light load may remain well under any pressure/excursion levels that would induce distortion. Tough to say.

There's not exactly much info on the TB 8"x12". I can't find much of anything for user reviews/comments or test info on the woofer.


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## 300Z (Mar 20, 2005)

AJinFLA said:


> I don't know if there is any type of phobia or backlash here about using "mass market" brands (with enormous R&D capacity), but these JBL's http://manuals.harman.com/JBL/CAR/Boxes and Parameters/GTO 804D.pdf would spank the pants of the SEAS (a brand which I like - I own W22's among others) as subwoofers (as opposed to midbasses) - which is what I _think_ you are looking for.
> 
> cheers,
> 
> AJ


I'm planing to use a single GTO804 for my sub duties when i get the time to redo my system in the next couple months...
I'm planing to reduce the "size" of my system to a very basic setup and that GTO804 seems to fit my requirements nicely. Small box, decent x-max, low inductance, good power handling.
I've always had decent to very good results from JBL subs. Reason why i decided to use the GTO804.

Crutchfield is selling the GTO804 for $72 which isn't bad IMO especially from an authorized dealer with very good CS support. 

Leo


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## ca90ss (Jul 2, 2005)

300Z said:


> Crutchfield is selling the GTO804 for $72 which isn't bad IMO especially from an authorized dealer with very good CS support.
> 
> Leo


If you have a Jbl dealer locally you should be able to pick one up for ~$60.


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## mvw2 (Oct 2, 2005)

Um, local audio is kind crappy where I live. Let's see... We have a Best Buy(yay), a tire shop that wants to sell car audio too(finally have Clarion locally  ), and we have a relatively new audio shop that carries Eclipse and Kicker stuff. That's about it. We _had_ an Audio King a.k.a. Ulitmate Electronics, but they went kaput when they built a big store and didn't have the business they were hoping(retail pricing probably killed them).

An hour or so drive up to the Cities will get me a lot more though.

Harmon Kardon does do pretty well, so I don't really fear their products.

The big picture of all of this is myself trying to find the one, single, best option available that will fit my design goals and limitations. The tough part is there are just lots of great and plenty doable choices available; it gets tough to decide.


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## 300Z (Mar 20, 2005)

ca90ss said:


> If you have a Jbl dealer locally you should be able to pick one up for ~$60.


Really? 
Good to know... I do have two pretty close to me but i've never went inside the stores, so i don't really know what they have i just know they sell JBL because of the big signs they have on the outside...  

Thanks
Leo


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## 300Z (Mar 20, 2005)

One other thing to consider is how accurate the T/S specs provided by the manuf... as far as the TB go... I've also considered using some of their products but went with different brands instead, based on info collected from multiple reliable sources. Unless TB has got better recently i would look elsewhere.

Why not just a sealed box? That JBL will work pretty well in only .3cu.ft, that's pretty small and wouldnt take much space at all.
ID8v3 will also work in a pretty small box too.

Leo


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## cvjoint (Mar 10, 2006)

So 4 years have gone by and I haven't seen these used yet. What was the op's choice? Are these 8x12 TB subs decent? Do they have motor noise, shorting rings, production consistency? I might have an interesting application for these.


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