Sub Recommendation

[bdubbx]

Hey all...it's my 1st post, but this site comes up on a lot of my google searches, so I figured I'd ask for some help.

I'm fixing up a '70 Chevy Blazer 2wd. If you're not familiar with it, it's got a fully removable top which I have never had on. I've read this could be a problem with hearing music/bass on the freeway. I've never had a stereo in it, but have picked up a few parts to get me started:

Deck: Kenwood KDC-X994
Components: Polk Audio MM6501
Amp: Kenwood (don't remember the model, but I think it puts out 150w rms)
Deadener: I have enough to cover most of the floor/doors
Nothing is installed yet, and I still need to build my 1st ever kick panels

My next purchase is sub(s)/amp and figure out the best enclosure. My goal is to have a good-to-great sounding system that is well balanced and can be heard if not loud on the freeway.

I've always wanted 12's since I've only had 10's in the past, and have been looking at the RE Audio SEx's. My concern is would this be too much for my highs to keep up with? If so, what would you recommend and how you would build the enclosure? I've built about 6 enclosures now, but all sealed. I don't mind building a ported one, but I'd need A LOT of help with the design because the port tuning confuses me.

Thanks in advance, and here's some pics of the Blazer so you know what I'm working with:

[bdubbx]

Oh, guess I should mention that I listen to mostly rap/hip-hop and then it's rock or R&B. My current power/electrical system isn't all that great, but I have a 100 amp alt. My trunk space is pretty big. I do have my air ride tank and a box holding all the valves back there already, but I'm willing to redesign/reposition that to make room for a box if necessary. I only drive this thing where I'll be around it the majority of the time, so it doesn't need to be weather proof or really theft deterant either. Thanks again!

[hooligan72]

If you keep the top off while your going down the highway you are going to lose most of the energy the subs deliver right out the roof. That is if you put the subs in the back.

If memory serves me the old school blazers have a lot of room between the seats. I would reccomend building a center console with downfiring subs in it. This should allow you to at least feel good strong bass even at highway speeds.

[bdubbx]

Thanks hooligan72. My top isn't in good shape right now, but a few years from now that might be different. Unfortunately, the center console isn't an option. I already have a stock center console that I paid too much for and can't cut it up/modify it to fit a sub.

Rather than the rear, would putting the subs in the middle of the blazer be ok? I could possibly make a box that's long and shallow that runs across the entire sides and have the sub facing the center of the cab. The actual location could be between the front seats and rear bench. Is it purely volume (not depth or anything) that matters when building an enclosure?

[caraudiobum]

You are going to have some acoustical problems no matter what you do since it won't be in an enclosed space. People get away with relatively little power to subs in a vehicle because the bass resonates in the cab, effectively amplifying the sound. Take that away and you'll have to have much more power to get the same dB level -- perhaps 5x+ more power (if its in the trunk, though that depends on many things.

Though while driving, you would need even more than that. I wouldn't suggest anything less than 1kw RMS. Those RE subs should do well. A JBL 1200.1 would work very well with them, and you should be able to get one used on ebay for $250-300. It is rated at 1200w RMS @ 2 & 1 ohms, though they actually put out 1400 or so RMS at 14.4v. Those subs (600w RMS each, with 2 ohm DVC's) can be wired for a 2 ohm load on the amp. The only question would be keeping the amp fed... but that's a question for someone else.

[Cr@sh]

I would recommend building a ported enclosure and building a minimum 1" loading board to place over it, something like this:

[Cr@sh]

Yes your going to lose no matter what this has worked quite well in the past.

[bdubbx]

Thanks for all the responses! I never got an email and figured no one was responding...

So, I take it 2 12"ers are recommended over 1, and I'm noting the minimum of 1K watts. I like the idea of the used amp to save money, but is buying a used amp safe/recommended?

So, I have a couple questions on a ported enclosure. Does pointing the port towards the driver help? I ask because if the port was on the bottom of the box, there'd be like a passage it would be facing going underneath the rear bench towards the driver seat. I don't know if this does anything, or is even recommended in a ported enclosure...

As for the top loading board, it's a good idea (I'm assuming it's just for being able to place things on top of it?). I'm hoping to actually build it as shallows as possible in order to retain some storage in the back. I would like to shallow and tall/wide if that's an option.

Given everything that's said, am I right in that I'm probably not going to have to worry about over powering my components with this type of set up? I looked the other day and my Polk components are 2 ohms 100 w, and the amp puts out that much at 2 ohms.

On another note (sorry, to have so many questions too), I know rear fill isn't the best for sound staging, but I guess I'll have to live with the fact that I'll never really have a good sound stage with no top...so, should I put in some rear fill speakers between the driver and rear bench for people in the rear to be able to hear?

Thanks again all!

[revboden]

The cloth roof will not pressurize, so don't worry, you'll never have cabin gain. Two average 12" subwoofers at 2m will output about 110db. which should be enough to hear... 100 yards away... Subwoofers are omnidirectional, the direction you point the ports dosen't matter as long as there is enough space for the port to breath without interference. The top/loading board would have to be 7ft x 7ft long to effect a 40hz wave... i wouldn't bother.

suggestion: download WinISD Pro, ( LinearTeam ) read the help files, enjoy.

[Cr@sh]

Originally Posted by revboden

The cloth roof will not pressurize, so don't worry, you'll never have cabin gain. Two average 12" subwoofers at 2m will output about 110db. which should be enough to hear... 100 yards away... Subwoofers are omnidirectional, the direction you point the ports dosen't matter as long as there is enough space for the port to breath without interference. The top/loading board would have to be 7ft x 7ft long to effect a 40hz wave... i wouldn't bother.

suggestion: download WinISD Pro, ( LinearTeam ) read the help files, enjoy.

X2!