[DaveN]

I have finally received and installed my new Infinity Reference Series speakers - out with the Nokias! However, when I powered everything up with the new sub in the cubby I was less than impressed with the rear sound. Doubled checked, nay tripple checked the phase so that's all good. The speaker grills are about 1/2 the size of the 6.5" speakers and the cavity behind them is not really acousticaly designed in any way; it's just open to the inside of the fenders. Has anyone cut "Ack!" a hole beneath the existing horizantal grill and installed another grill to expose more speaker surface area? Filled in the wheel wells to create a pseudo speaker enclosure? I worry about trapping moisture in if I do this.

Suggestions?

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[DaveN]

Nobody? Not even the Great and Powerful Flash has a suggestion <img src="/forum/images/smilies/968/rolleyes.gif" class="smilie" alt="" />

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[flash]

lol - i have plenty, but i wanted to consider this carefully, and felt that more time was needed to give a better response - i'll get back to this tomorrow after i've cleared out the superbowl party

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[DaveN]

Forgive me oh great one, I know not the pleasure of sport. I humbly await your sobriety <img src="/forum/images/smilies/968/tongue.gif" class="smilie" alt="" />

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[flash]

roflmao - if you only knew.................

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[flash]

okee dokee - now that i have my head somewhat clear, let's see if i can help here



the first order of business is that the head unit must be capable of driving the components - the factory radio won't sound good no matter what you hook it up to



the head unit must have at LEAST 18 w/ch RMS - this will be the absolute minimum to drive any kind of bottom end at all



it must also have at least 3 full parametric bands of EQ, and preferably 5, or at least 7 bands of graphic EQ - this will be needed to adjust for the cabin anomolies



then we can start talking about the fronts and adding crossovers - you can put some small caps on the fronts if the deck doesn't have that capability - that will cut out everything below 150 and keep them from distorting - i'd also add some dynamat extreme behind them on the sheet metal of the door



in the rear, you can make an enclosure of sorts using dynamat extreme on the sheet metal, and then expanding foam to seal it, and then adding holofill to tune - then you can install a 6.5" woofer - i like the JL Audio for that - it goes lower than anything else i've seen so far in that size - this will require though that the deck has subwoofer outputs via the rear speaker lines - pioneer does that - there is a control that you can set to change the rears from full range to sub



this will be the simplest way to decent sound - it will mean though that the rear seats sound like crap to anybody sitting there, as all they will get is low end



hope that helps

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[DaveN]

Tks for the input. I was worried about foam filling in the cavity as I didn't want any moisture trapped in there but as I don't part outside I should be ok. I have a new Pioneer BT deck installed with all the bells and whistles so power and freq control isn't a problem - more bands and variable slopes than I know what to do with. I have put new Infinity component speakers in the front doors and they have their own separate crossovers. All that sounds fine. I have my new sub in the rear cubby and that sounds just fine too (for an 8" sub that is). Fills in nicely at <100 Hz with an 18Db slope.

The Infinity 6.5's in the rear just sounded so washed out even though they are coaxial and have an adjustable crossover. The speaker grill only reveals about 1/2 of the stock speaker area and I was thinking about cutting out and adding more grill to unblock some of the driver?

Getting in there to fit metal bulkheads might be a bit fun, my had is about the same size as the hole. I could crumple up a ball of alum foil <img src="/forum/images/smilies/968/rolleyes.gif" class="smilie" alt="" />





And no one sits in the back! Who would want all that extra weight <img src="/forum/images/smilies/968/tongue.gif" class="smilie" alt="" />

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[flash]

you would be amazed at what the dynamat extreme will do for the sound - it takes all the resonant mid range reflections out and allows the speaker to do its work a lot better

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[DaveN]

That was a whole different topic. I was also considering sound-proofing as I had the rear apart and the front/rear panels off but I was wondering if I was wasting my time unless I wanted to rip all the carpets off the floor too. I found an excellent article with real accoustic measurements on typical installs. I wasn't sure I wanted to add that much weight to the car. I also found a Canadian product that tested just as well but for WAY less $$$ - B-Quiet especially if you have USD.

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[flash]

i didn't have to use that much to get the results i wanted - added maybe 15lbs max - i did the same thing though on the denali and it is an entirely different world in there now - i used about 30lbs on that car - every surface top bottom and sides - absolutely amazingly quiet - of course now that it isn't drowned out by the road noise, i hear every little noise the car makes



it looks like the same kind of stuff, and probably works just as well, but as much trouble as it was though to install, i'm not sure i would try out other products as opposed to a known result - i'm just way to lazy to do it twice - but if cost was an issue, i would probably go that route

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[Jamie '92 968]

Flash,

I recently put a pair of Kicker 6.5" subs in the rear of my car, driven by a Rockford Fosgate P300-1 amp with a lowpass filter.
These things give my system an amazing punch.
I went with the Kicker subs because they were rated for free-air installation and I didn't want to add an enclosure (keep that stock look...).

The low end of the woofers suffers a bit, and I was trying to come up with a way of building an enclosure inside the fender behind the speakers. Right now I just have them installed in a foam baffle with a hole cut in the bottom. I also added some spray-on sound dampening stuff on the sheetmetal inside the fender.

Can you provide more details about the Dynamat / expanding foam enclosure concept?
Is the foam stiff enough to act as a proper enclosure?
Do you have to worry about obstructing the air-flow through the fender? I'm not clear why the airflow path from the door through the vent into the rear fender is important, but it must have some purpose, since they put the vent there for some reason.

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[flash]

yes, if you want the airflow from the hvac system to reach the rear, then you need to provide a duct to do that - however, you can enclose the area and still do that - it just takes some plumbing - i'll be tackling exactly this project within the next couple of weeks - going to do it on a car here - i'll be scheduling it in about an hour - i will fully document that procedure for you and everyone else as soon as i'm done

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[DaveN]

This is the same thing I will be doing soon but I am glad you mentioned the reason for the door ducts. I was concerned about why they were there and what blocking them would do. Don't want any trapped moisture! As I have only one sub in the left rear cubby I assume the right path will still allow most of the air flow to happen. No one rides in the back anyway [img]style_emoticons/<#EMO_DIR#>/wink.gif[/img]

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[Jamie '92 968]

Can't wait!

In the mean time, I'll continue tracking down all of the little rattles and resonances I've discovered / created with all this additional power...

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[DaveN]

I just purchased 50 sq ft of B-Quiet and will be putting it in the weekend. Mostly in the rear and the the wells to cut the road noise from the spare tire delete and the odd buzz that my sub now creates.

It's a lot cheaper than Dynamat and just as good. Considering the USD it is a steal for anyone south of the border (my border that is) as it's from Alberta.

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[flash]

well, as things sometimes happen, what was slated for today got pushed back and this project got pushed to the head of the line - just did it today - very happy with the results - will post DIY shortly

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