Need help with subwoofer

Bear6360 · Aug 5, 2003

Hey guys!
In my Z3 there are two 5.25" speakers between the driver and the passenger seats. I want to find some 5.25" subwoofers....not 2 way speakers. Does anyone know where I can find some? I found a 6.5" subwoofer by Rockford Fosgate, but I'm not sure if I can fit it in place of my 5.25"s.

http://store.yahoo.com/csexpo/rfrofo6carsu.html

Has anyone tried this upgrade in a Z3 or know anyone who has? Do 5.25" subwoofers actually exist?
Thanks! [cheers]

BMWlover · Aug 6, 2003

There are a couple of things to be considered (however, not 100% guaranteed, 'cause I didn't have any experience to see the inside of Z3 in person.) [V]

1) OEM 5.25" speakers are full range speakers but a subwoofer is a limited-range speaker of frequency (usually under 100 hz)
2) Even though speaker cone sizes are same, a subwoofer's magnetic size is much bigger than that of full range speaker. Thus, much bigger space is needed.

BMWlover

Bear6360 said:

Bear6360 · Aug 6, 2003

Re: Re: Need help with subwoofer

BMWlover said:

Yeah. That's kinda what I'm lookin' for. I want something with some bass. I have room in my kick panels for 6.5" speakers. Maybe I should put 2 subwoofers down there?

Bear6360 · Aug 6, 2003

Here are some links to the Z3's speaker layouts:

http://mz3.net/articles/069.html

http://mz3.net/articles/068.html

http://mz3.net/articles/064.html

http://mz3.net/articles/150.html

Sorry there's not a good one of what the subwoofer looks like. It's about a 6.5" x 6.5" square between the driver and passenger. I think if I squeeze the 6.5" sub in, I won't be able to put the stock grill back on (no big deal to me)....but it might look a little crappy with a round speaker in a square hole. ....then again, the speaker might stick out in front of the hole anyways. This is one of those things I won't be able to tell for sure until I either take measurements or just buy the darn thing and try to put it in.
Thanks for the advice BMWLover. I'll be lookin' for more! [cheers]

BMWlover · Aug 6, 2003

Bear: I think a round speaker in a square hole looks a little bit crappy [:D]

.

After reading articles, I came to understand that a mere upgrade of 5'25" woofer is not a good choice. If you want to have a maxium performance of woofers, (1) you need to add a good crossover. Without a crossover, you may find no difference. (2) you need to have a large space behind the kick panels (It seems there is a very tiny space)

Furthermore, though Z3 is sealed very good, the distance between front seats and rear trunk is so close. For this reason, if you are longing for a deep base, then, just a change of woofer is not a good choice.

Why don't you upgrade your Subwoofer system? It will be cost effective and easy I guess. "Recognizing Bass" - there is no correct answer, there is a bankruptcy ahead...heheh... good luck! [wave]

FYI, Infinity Basslink is a good alternative solution.

BMWlover

Bear6360 said:

illfos · Aug 6, 2003

hey bear!! what's happening? You know I was thinking about this all day trying to come up with the simplest solution to this problem you have. I can't remember but is the 2 speakers in the Z3 that are between the seats on a panel that is straight, or is it sorta curved? Cause I was thinking, what you could do was get a piece of 3/4" mdf and cut holes for a 6.5" mid sub and place it over the 2 oem holes, and then screwing the 6.5"s to the mdf. See the 5.25 oem would obviously not be big enough, but it the 6.5 was raised slightly off the OEM hole, i think it would fit fine. You could cover it with vinyl or carpeting. I think getting a local shop to make a piece like this for you couldn't run you more than 100 bucks.
i would keep the kick speakers, because of sound quality reasons.
Now lets say the panel is curved...then you might have a little more of a problem. construction would be slightly more complicated. You or someone else would have to make a mdf ring for the OEM speaker hole, or you could get a local shop to make a fiberglass piece for it.
i thought that the Z3 has a sorta glove box behind the seats? if so you might be able to put a custom box out of fiberglass inside there. Without really being in the car, It's hard to picture the perfect solution, but i think this might be enough to go on. SEE YA!!

illfos · Aug 6, 2003

hey ahahhaha why is this my second post...i thought i had like at least 50 posts or something...damn

CarpePM · Aug 8, 2003

Hey-

I applaude you for trying to make the most with what you got. May I recommend checking out Parts Express website. They have some of the best selection of speakers out there. They do make 5in woofers like this, but in a car they generally won't be able to make enough headroom. Since this is a sub channel, try a couple 5in (8ohm)woofers wired in parrallell (4ohm), then run them into a 2ohm stable amp bridged. (Amp should be stable bridged with a 4 ohm load (i.e. 2 ohm stereo).

Here is an example of a good quality one:
VIFA MG14WK09-08 5-1/2" WOOFER

Specifications: * Power handling: 35 watts RMS/110 watts max * V.C. Diameter: 1" * Le: .72 mH * Znom: 8 ohms * Re: 5.60 ohms * Frequency range: 40-5,000 Hz * Fs: 45 Hz * SPL: 87 dB 1W/1m * Vas: .49 cu. ft. * Qms: 1.99 * Qes .35 * Qts: .30 * Xmax: 3.5 mm * Dimensions: A: 5-7/8", B: 4-9/16" C: 2-3/8".

These are even better:
FOCAL 5W4211 5-1/4" "W" CONE MIDBASS

* Power handling: 50 watts RMS/70 watts max * Voice coil diameter: 1" * Le: .59 mH * Nominal impedance: 8 ohms * Re: 6.6 ohms * Frequency range: 47-9,000 Hz * Magnet weight: 20 oz. * Fs: 46.5 Hz * SPL: 88.5 dB 1W/1m * Vas: .48 cu. ft. * Qms: 4.17 * Qes: .3 * Qts: .28 * Xmax: 3.2 mm * Net weight: 3.5 lbs. * Dimensions: A: 5-1/4", B: 4-1/2", C: 2-13/16", D: 4-1/16".

You can search their site for 5-6 inch woofers

But if you really want to feel some bass, probably should get the Aura BassShakers....

I know they look stoopid, but you will feel it!

illfos · Aug 8, 2003

i would not go with the 2 ohm setup. I mean if you really aren't concerned with sound quality than that's cool. But i think it would be a better idea to stick with the parrell setup with a 4ohm load running into it. In fact I would even go with a larger amp and run 8ohms. 8ohm stereo ohhhhh man wowowow the quality would be amazing. Focal 5 incher on a xtant amp 8ohm load jesus my mouth is watering...

CarpePM · Aug 8, 2003

I think you misunderstood... Running two 8 ohm speakers in parallel yields 4ohms. Most all amps that are bridgeable can handle a 4 ohm load when bridged without too much distortion.

Don't worry too much about that sound quality when you are talking about frequencies below 350Hz. Especially when you consider you box design. You will lose way way more quality by installing woofers in a box that wasn't tuned for them. Not to mention the overall sound dampening (density) of the material. I am not too familiar with the area you want to put them in, but I am assuming it is going to be sealed? If not, without being able to tune any ports, it will always make a wiffling sound, and the speakers will die faster because the resistance to their movement provided by the box (Q box) won't be there. They would have to rely on the strength of the surround and the spider (Q ts).

Just my opinion....

As far as making an amp drive 2 ohms: I have a Phoenix Gold MPS2250 4ohm 50 X 2 Amp. It's dynamic output at 1/4 ohm is like 1375watts, with .1 THD (Yes, they used to make amps that could do that). I have used it to drive 6 JL12W6 Subwoofers, 8 JL Midbassess, 6 Kicker 3.5, and 3 Infinity EmitK ribbon Tweeters at the same time. I used all hand tuned crossover components by buying larger value coils and unravelling them untill I achieved the best crossover points. In some cases, like the subwoofers, which were pulling a one ohm load on the amp, I had to build parallel coils because the 1375w travelling through it would melt the insulation. No one builds systems like this anymore, because everyone wants surround sound video systems. But let me tell you, nothing is more impressive than a hundred watt amp driving 16 speakers in 4 ranges each receiving close to 1375 in each range. Except maybe welding with your amps speaker outputs!!

Sorry if none of this helps you. Just wanted to help you find a resource that has 5 in woofers.
If you are really set on using car stereo speakers because they come in 4 ohm models, you can always try the density method..... Buy a couple high power 5inchers and make the cone heavier using some plastic dip or varathane or something depending on their material. This will lower the resonant frequency of the speaker. It's not a great method because the speaker will become less efficient.

Remember that you don't get anything without trading something.....
Trunk space for deep base. It will either be hidden or it will be heard.

CarpePM · Aug 8, 2003

Ooops... Forgot to give you the link.....
www.partsexpress.com

Look at this one! Its almost the perfect speaker for you.. [thumb]

LOOK AT THAT BASKET! ITS HUGE!
Specifications: * Power handling: 60 watts RMS/85 watts max * Voice coil diameter: 3" * Nominal impedance: 8 ohms * DC resistance: 6.5 ohms * Frequency response: 46-2,500 Hz * Fs: 46 Hz * SPL: 84 dB 1W/1m * Vas: .27 cu. ft. * Qms: 4.52 * Qes: .43 * Qts: .39 * Xmax: 5.0 mm * Net weight: 3.5 lbs. * Dimensions: A: 5-15/16", B: 5", C: 2-7/8", D: 4-7/16".

Notice the Xmax: 5mm Thats the speakers distance of travel in and out. Most 5inchers only move <2mm, most 6inchers <4mm, Kicker 8's only travel about 7mm. These little guys really move....

Here's their spec sheet.
http://www.partsexpress.com/pdf/297-439.pdf

illfos · Aug 8, 2003

ahahah sounds like you have a lot of equipment running...any speaker running on a load below 4ohms, resonates to much to sound good in my opinion. When that cone is resonating and it has to spit another hit out, before it has recovered from the last one, it annoys my ears. But then again i use 8" subs on a front stage stereo and compete in sound quality so what do i know.

CarpePM · Aug 8, 2003

illfos-

Not trying to be facetious. Sorry if my comments offend you. I must have been reading a little too much into your comments. Just trying to help the guy who asked.

You should know that the speaker is the load. No matter what it will always be at its rating, whether its 4ohm or 8ohm. The number of speakers and the way they are wired effects the amount of current that an amp releases, because the max voltage out from an amp never really changes. Most distortion comes from having too many signal processors and connections.

The sound your refering too, the sloppy bass, really has more to do with overall box design than to do with electrical. Ask the people who designed and installed your competition system. The reason cars run 4ohm speakers instead of 8 has more to do with car history than any distortion.

No, I don't run stereo equipment anymore... left Iasca 8 years ago.... pursuing much better stuff now.

illfos · Aug 8, 2003

I designed it, took last years east coast regionals with it.
2 ohm and below loads produce to much cone resonation (vibration). For instance a tuning fork. If you hit a tuning fork it resonates, if you try and hit the tuning fork again, and it hasn't recovered yet, you'll knock the tuning fork right out of your hand.
yes there can be resonation because your box isn't strong enough. But that's not what i am talking about...i am saying that a speaker run on a load 2ohms or lower will take to much time to recover and in turn will not sound right in my opinion.

didn't take anything wrong just stating my opinion on the subject

CarpePM · Aug 8, 2003

I understand your point, but I think that most amps these days can run 2ohms in stereo (4ohm bridged) pretty easily without significant latency problems. If the box provides the right Qb and the right Fb, it should resonate above the band of the crossover point. I haven't done much testing on this, but come on, considering the subject is trying to get the best sound out of two 5in holes, I am sure you can see where I am coming from. The best speakers for this are probably going to have to be 8ohm speakers, there just isn't as good a selection in 4. So to run those 8 ohm stereo he would need to get an amp with four times as much power to get the same power output. I just don't think the cost and space required for that (especially in a z3) really merits the sound quality difference. It's a convertible after all. Just my opinion.

Then again maybe I just like being the Devil's advocate. Thanks for being mine.

Best Regards,

BMWlover · Aug 8, 2003

I agree with both you guys. I heard that most amps these days can handle 2 ohms (bridged) speakers. However, that's not a usual setting, normally 4 ohms. If you see home audios, almost all audios are running 8 ohms. Why? because 110V home electricity has its richness to cope with high ohms and a good resonation of cones. Car audio? usually 4ohms because only 12V DC has its limitations. For that reason, if there is a 8 ohm car audio, that should be really expensive for good quality. I didn't have any experience to hear 8 ohm car stereos in person. Hope I can hear some day soon. [:D]

CarpePM said:

Bear6360 · Aug 10, 2003

illfos said:

You have to sign onto hotbimmer.net and go to My Account to get the post number to transfer to this new forum.

Bear6360 · Aug 10, 2003

illfos said:

That sounds like an interesting idea. I'll have to find someone in my area to help with the custom work.
The panel you're referring to is straight.

Right now, I have a new amp to put in. It is a U.S. Acoustics 85x4 watts. The model is USB4085. I'm wondering if I should replace the stock amp or if I should try to wire BOTH amps. I have 10 speakers total. I was thinking of wiring the smaller speakers to the factory amp and the larger ones (kick panel and subwoofer 5.25") to the new amp. Are there any considerations to wiring two amps in a car?
I'm not really experienced with car stereos....I'm just learnin' as I go. Any info would be a great help. Also, I'll try to find a page with specs on my amp and post it.

The point of the new amp is to see if it will give enough power to my subwoofer so I won't have to replace it. I'm thinkin' my sub was just not receiving the power it needs.

illfos · Aug 10, 2003

yeah i would defintely not use both amps. The 10 speaker setup that you are talking about it consists of 6 tweeters(2 being 2in) and 4 midrange i think. Using the stock amp would make your car sound very strange ahahah. First of all the stage you put the stock amp on would be a lot lower than the other stage, because of the power it puts out.....wait a second i just thought of something...you didn't replace your stock speakers did you? If not then you can't put an aftermarket amp on them. WAY to much power. You would need to replace the OEM speakers when you install an internal speaker amp. If you remove the midrange speakers we were discussing before, I would suggest going for a 4 channel with hi/lo pass and a bult in EQ, because you have limited space. This way you could put the new midbass speakers on the rear channel, LO pass. And then the fronts on the other channel. Xtant makes a nice 4004 just put one in my brothers car on focals...sounds like you inside the CD. see ya bear

P.S. can't find where it says to foward posts to new board...you know exact spot???

Bear6360 · Aug 10, 2003

All of you guys are giving me great advice! Also, just by listening to your convo (reading it [;)]

), I am learning a lot.

Right now, my sub is two 5.25" speakers (one face front of the car, and the other facing the back - head to toe so to speak - for space efficiency).

As stated above, I want to try to install the new amp first to see how things sound after that. If they (speakers) are still not up to snuff, I will upgrade the sub. I'll also upgrade the kick panel speakers from 5.25" to 6.5", but I'll keep them as 2-way or even 3-way speakers. A new sub (or two) will be enough bass. Speaking of a new sub or two, I'm wondering how big of a sub I will be able to fit in the space where the sub resides now. I think a 5" sub will be a bit bigger than the speakers that are in there now, hence, only one will fit....but not sure yet.

Back to the amp......would I be able to run two amps in my car? I don't know the specs on the factory amp. 40 watts is all I know. I don't even know how many channels or ohms.

I'll try to find some specs and post them....

Need help with subwoofer

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