small subwoofer

[onobeka 10+ year member]

Hi guys,

I have some questions regarding a subwoofer that I consider building. Maybe they are dumb ... you'll be the judge //content.invisioncic.com/y282845/emoticons/biggrin.gif.d71a5d36fcbab170f2364c9f2e3946cb.gif.

I'm looking for a small unamplified sub. I'm planning to build a small woofer like those of the home-cinema 5+1 systems. So something like 40-50W RMS. The head-unit should be powerfull enough to power it since it's a 27W RMS Pionner with the peak of 45-50W. I'm thinking about the band-pass box since it would amplify better and eliminate cross-over - maybe. So this would be something very very simple. I just want a little extra bass to help the front compontents. The fronts are installed in the deadened doors and they run on the head-unit. So I don't plan to install an amplifier. Maybe on the next car, but on this I don't want it.

Do you think that a small sub made out of a 6.5" or a 5.25" woofer can work or it's just crazy?

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[supa_c 5,000+ posts]

Its a dumb idea. H/U's werent made to power subs.

You dont even have a crossover so it will play all the treble too

 

[faulkton 5,000+ posts]

I dont think your going to get much from a 5.25 powered from a HU. I think you would be much better off with at least an 8" woofer powered by a small amp.

Now totally off topic but i have to ask, how big is car audio scene in Romania?

 

[onobeka 10+ year member]

I cannot reply to the question of the audio scene in Romania since I'm not into car stereo. I'm just a decent user who wants clear good sound and not extreme figures. That's why I said that something like a normal home-audio 35-50W RMS sub would be enough for what I want. That thing is small but it produces good bass. However I do not know about what good it would be in a car. Also that is powered actively so another difference.

I have to 5.25 mids at 4 Ohms so I was thinking about that small band-pass box.

 

[hoss 5,000+ posts]

as for going with the home theater idea of low power small speakers, car audio typically doesent work the same way. you have much more interference and background noise in car audio than in home. the road noise, moving air, engine noise, etc... causes a loss in percieved efficiency, home theater is able to use less power and still get good results because of the lack of this. also, the HU rated 27w rms is more likely closer to 8w rms... HU's dont really put out a whole lot of power.

and im not gonna say that a 5.25 isnt going to have the ability to get low, but its kinda unlikely that it is going to be able to get real low. id agree with the suggested 8" and a small amplifier.

 

[onobeka 10+ year member]

Thanks for the reply. I understand perfectly the opinion about bigger subs and amps. I have the HU (pioneer) with 4x50 RMS peak and 4x27RMS continuous power as rated by the producer. The Infinity 6.5" components are louder than normal needs and even for more high power usage, or that is what I think. The bass is ok since the doors are deadened and the tweaters sound amazing to me.

What I would like to have is something to fill out the back of the car but I can only mount 6x4" co-axials. I think that those however good the brand might be will not produce a good effect. High freqs coming out of the back isn't gonna be good since I don't want to install sound for the people traveling in the back. 99% the car carries 2 persons in the front only. So I was thinking about the small subs. I have the 5.25" mids. I thought a good box design would get engough low freqs out of them. So it isn't gonna be any big investment, maybe box construction but that's it. If they would produce an extra bass to help the fronts it would be enough, so that's why I'm not so afraid about not having enough power, but anyway I wanted to consult you guys before I go further.

 

[squeak9798 5,000+ posts]

You dont even have a crossover so it will play all the treble too

That's why he mentioned the possible use of a bandpass enclosure; which is basically an acoustical highpass and lowpass on the subwoofer //content.invisioncic.com/y282845/emoticons/wink.gif.608e3ea05f1a9f98611af0861652f8fb.gif

What model Pioneer do you have? Some of the older models were actually rated to do 70w RMS @ 2ohm on the rear channels.

 

[onobeka 10+ year member]

I have one from the latest 7 series. It's the lowrange deh 3700 mp, but I might switch it to the 4700 soon. The only difference I can see between the 3700 and 4700 beside looks for what's interesting in sound quality is that the 4700 has the mosfet amplifier and a little more powerful.

My midbasses are 4 ohms but If I will wire them in parallel that would be 2 ohms. The head-unit has only one preamp for the sub. But I don't want any amps so I was thinking about two bandpasses, one for each speaker and connect them to the rear outputs from the HU, so normal amplified/equalized full range freq from the HU in the bandpass enclosure with small mids.

Of course first I was gonna try one enclosure //content.invisioncic.com/y282845/emoticons/biggrin.gif.d71a5d36fcbab170f2364c9f2e3946cb.gif to see if that works.

 

[jim163 10+ year member]

I Used to run 2 12" kickers off an old pioneer head unit, It had the option of turning your rear speakers into a subwoofer and it didnt sound bad. But your probably going to want more just do it right the first time.

 

[OnYrMrk 10+ year member]

Romanian dude,

I know someone who is running a JL audio 6w0 off his HU and it sounds good, not great, but good. You might look into one of them. Ported box is what sounds best for those. Also you might look at Ebay and try to find a discarded factory sub from an Explorer or Mercury Mountaineer. It is a 6.5" woofer and runs off 12 watts.

just my .02cents

 

[onobeka 10+ year member]

Ok, OnYrMrk ... dude,

what kind of an enclosurewas the 6w0 placed in and how was it wired to the HU?

 

[OnYrMrk 10+ year member]

don't remember the size of the box, something like .5 cubic feet ported, I am not sure how he wired them to the HU.

sorry about the dude remark, but I didn't remember your screenname

 

[Raven 10+ year member]

If that your HU is two ohm stable (Send an email to Pioneer with the model number on your HU) you could get a dual 2 ohm woofer and attach each rear channel to each VC. Would be pretty decent power out of a HU.

 

[supa_c 5,000+ posts]

The only unit that i know of that does that is the 5500MP. You can bridge the rear channel and get a 2ohm load. I believe it was 70W. Not to mention that the lower impedance will cause the amplifier to run hotter. Which isnt what you want to do in a closed dash

 

[Spkrman]

get a passive xover for the woof, http://www.partsexpress.com has em for subs.

You can do "enough" bass with a head unit if you work on the box design... I've been there //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif