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Discussion Starter · #1 ·
Someone had a good suggestion of not simply installing my 3.5" dash speakers as free air. I have been thinking all week and finally came up with something - a Ziploc food container. I cut the lip off, cut a wire hole and notched it for the mounting ears. It is a perfect fit. I can run a small bead of silicone around the lip and seal it to the speaker frame.

Does this look like enough internal volume to get decent response from the speaker? It is a great fit. I have to recess mount the speaker due to the tweeter being raised. That is why you see spacers on the ears.

 

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not sure what you are looking to accomplish with the baffle. free air would provide better extension versus sealed. however, with 3.5" speakers, i don't think it really matters too much.
 

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Discussion Starter · #3 ·
I will rephrase my question: Would these work as decent enclosures to preserve what little bass response there is from them? I really can't go larger though I could wrap some duct tape around them to stiffen them a bit.
 

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you would likely lose what little 'bass' response there is from them, as a small sealed enclosure causes faster roll off versus a IB setup, which is essentially an over sized sealed enclosure. one quick thing, though, when you say free air, are you saying there is no baffle on the speaker? meaning the front and back of the speaker is not separated?
 

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What vehicle is this going into? You can also consider stuffing high density foam into the opening in the dash, to give it more breathing room than the plastic container. Please let us know which route you take, and how it sounds.
 

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Discussion Starter · #6 ·
There is no baffle, the dash hole is bigger than the speaker. As a result, the front and back of the speaker are not separated. Here is a pic of what the dash looks like when installed. There is 1/2" gap around each speaker. I really cannot get to the backside either. Through the top is my only option, hence my idea about enclosing the speaker.

 

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The cup doesn't act to reinforce bass response, because there really shouldn't be any bass sent to a 3.5". You should have them x-overed at 200hz or higher IMO. What the cup does do is isolate the speaker from the bass response coming from other larger speakers. This helps to reduce coloration of the midrange.

Most high end home speakers include sealed chambers behind the midrange speakers to isolate the mid from the woofer response. The very best ones also include a dampening material inside that chamber to further cut down on internal reflections and coloration. I'd take those cups and pack them with lambswool or a similar synthetic fiber. It should be a dense fiber, not like subwoofer polyfill.
 

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Discussion Starter · #10 ·
The speakers came with bass blockers. I am not sure what freq they cross at (they are stamped 200uF 50V) but I was planning to try them as soon as I am ready to hook everything up.
 

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Factory dash speakers usually use a foam gasket (sealed to the grill) to isolate the front wave. Your plastic cup is a good option to do the same thing for the backwave; I like that idea. Go with the cup if it sounds good. I believe the capacitor on the speaker is only for the tweeter, a simple 6dB/octave high-pass filter. The woofer runs full range, or there may be an inductor to provide a simple 6dB/octave low-pass filter. You can trace the wiring to see this.

I'm interested in your experiments because I have two vehicles for which I'm planning a similar setup. 3.5" dash speakers, actively high-passed at about 250Hz, and some bigger door speakers for midbass. So I'm interested in the results others are having with dash speakers like yours.

bg
 

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I did the same thing to some q-logic kickpanels... I used some tupperware that was a lil deeper than what you have there. Get something a lil larger... something thicker as well! make yourself a 1/2" thick mdf top for it and mount your speaker to that. I used some of that hardening epoxy to seal the thick tupperware to the mdf. Sounded waaay better imo than just freeair. If this is a 3.5 or 4" speaker this will be great! any larger and I would not do it. oh yeh... I also wrapped the outside of the tupperware with some deadener.
 

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The speakers came with bass blockers. I am not sure what freq they cross at (they are stamped 200uF 50V) but I was planning to try them as soon as I am ready to hook everything up.
That would be about a 100 hz filter for an 8 ohm speaker, 200 hz for a 4 ohm speaker. 1st Order (6 dB per Octave).

Calculator located [url='http://www.the12volt.com/caraudio/crosscalc.asp#cc"]here[/url] if you want to play around with other caps.
 

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I used the XTC foam baffles in the dash lots of times it can help them, but I had or made a baffle to mount them. The foam baffles you can just stuff into the hole if not enough room they will deform to fit, and you can cut slots in them to unload the speaker if you want and even tune them AP that way.

I suppose you can do it that way, you could aim them as well.
 
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