I am currently looking for the best method or material that can be used inside an SPL based enclosure that can help get an extensive increase in pressure.

Lots of people do different things but most follow others...

Typical things tried is-

sanding wood, applying resin, resanding, resin over, etc....

Ceramic tiles.

Using heavy material such as marble or granite(not what i'm looking for).

I am looking to find out if sanding and resining is what should be done, OR.. if laying material inside of an enclosure will yield better results.

sanding and resining can lead to human error with imperfections in the smoothness and this is why i'd like to see if there are materials out there to compensate for it.

I have a large list of materials to choose from but since i cannot physically touch them and know nothing else about what all is out there.. it's hard for me to just say... That's the one, hehe.

I have been looking at Acrylic based sheets and Polypropylene.

The goal is to have the finest, smoothest surface possible. Weight is also an issue so i cannot build an enclosure out of it, that's why i'm looking into thin sheets or laminate based sheets.

you using slot ports, round ports, or quarter wave style box. whats your tuning / peak frequiency.

it's a dbdrag style wall.

Tuning and peak will change with modification so it's not important.

The design isn't even started to be built yet but once it is, and tuning has been set, i will then need to smooth the surface and finish tweaking the tuning again to finalize the design.

There were two trucks at finals in tulsa that scored real high in db drag.

It looked like they had used some type of sheet metal ... real smoothe stuff. I couldnt get close enough. almost like a bandpass style (sort of) They called me to judge my truck so I had to walk away. We are trying go get one of our trucks past a 154 db with 2 15s in a quarter wave wall tuned to 57 htz. So we are in the same boat.

How about some sort of .25" plastic sheeting or plexiglass. Would be smooth as long as you didn't have seams.

it's possible.. I know a close buddy of mine capable of doin just under a 154 with a single 18, no wall.

It's possible, just harder.

I'm planning on downgrading cone area and increasing motor strength to get me tons louder.

I use ~400sqin of port but that's not enough for competition. I'm tryin to get at least 600sqin out of a car... this will be a challenge.

How about some sort of .25" plastic sheeting or plexiglass. Would be smooth as long as you didn't have seams.

Acrylic is plastic sheeting like i was thinkin about... and like u say, there WILL BE SEAMS :(

Plexi would be too heavy.

I dont think thickness would need to be 1\4".. i was aiming for 1\8" to keep cost down.

Anyways, jumping the seams is tricky. I found some stuff online that is suppose to be super lubricated that sprays out. Maybe i could spray that across the seams, i dont know...

we are talking about 76 htz maybe ...

frequency doesnt matter... It's just what gets you the loudest when tuning. My buddies car peaked lower and lower the more he tuned it.

He can do a mid 53 at 38hz with a single 18. He used to peak at 47hz.

I'm gonna try to start high, as close to 100hz as possible and work my way down until i peak.

How about some sort of .25" plastic sheeting or plexiglass. Would be smooth as long as you didn't have seams.

Acrylic is plastic sheeting like i was thinkin about... and like u say, there WILL BE SEAMS :(

Plexi would be too heavy.

I dont think thickness would need to be 1\4".. i was aiming for 1\8" to keep cost down.

Anyways, jumping the seams is tricky. I found some stuff online that is suppose to be super lubricated that sprays out. Maybe i could spray that across the seams, i dont know...

Up here in South Dakota Menard's carries 4x8 sheets of acrylic sheeting in 1/8" thickness! Not exactly cheap but would eliminate seams other than the where the sheets meet.

ahh .. ok ... I didn't Know what the max frequiency you could use. Thats what I was looking for. I'm going to look at utube, a friend of mine videoed those vehicles. Maybe we can find something.

How about some sort of .25" plastic sheeting or plexiglass. Would be smooth as long as you didn't have seams.

Acrylic is plastic sheeting like i was thinkin about... and like u say, there WILL BE SEAMS :(

Plexi would be too heavy.

I dont think thickness would need to be 1\4".. i was aiming for 1\8" to keep cost down.

Anyways, jumping the seams is tricky. I found some stuff online that is suppose to be super lubricated that sprays out. Maybe i could spray that across the seams, i dont know...

Up here in South Dakota Menard's carries 4x8 sheets of acrylic sheeting in 1/8" thickness! Not exactly cheap but would eliminate seams other than the where the sheets meet.

I found a 6'x3' sheet at lowes for about $47. They claim it's 20x stronger than glass.. Although i dont need it for structural support, it just has to be smooth.

I know formica is smooth... but it's pretty $$$ too.

where can I find a list of shows? They started a new SQ class around finals last year. I'd like to maybe meet up and talk shop.

if u feel like drivin to KY, TN, MI, etc... MECA has all kinds of shows there.

oh yes... I'll drive to shows ... best way to a points champion ... I'll bring some friends too. SQ and SPL vehicles.

u ever compete in MECA before?

Every sanctions rules are different. MECA's classes are FUSED unless you run the highest class in a certain division.

no not yet. Where is the rules located? I'm fused within 18" from every device and metal entry.

here it is-

2010 MECA Rules

U just need to focus on the SPL section.

I personally don't compete in SPL. My truck is a SQ vehicle. If MECA rules are more strict than USCAI, Than I'll just better myself when I compete anywhere.

By the way, Very sorry for throwing off your thread.

WOW ... diggin the sq rules there ... a challenge !!! this might happen in the near future !!

thanks ...

If you find what you are lookin for, please let me know so I can relay to TJ (our spl competitor).

i'm gonna have to stop by lowes and a shop recommended to me that works with different types of glass.

someone fill me in on the following if i'm wrong here.

Most people resin\sand\resin, etc.. to get that smooth surface as best as possible.

This can lead to human error about getting it perfect.

Others just use smooth tape. While they also may gain a little, it's not as much as a denser alternative.

I believe the reasoning is due to the enclosure flexing.

If the enclosure is flexing, then the tape is flexing with it and only helping a little...

IF the enclosure is stiff and rigid, externally braced and secured, then a smoother surface that is not structurally supporting the enclosure such as tape may gain more.

So people who use dense smoothing techniques are not only smoothing the surface but making it more rigid at the same time. Slightly but still..

It will be nice if you make a before/after test to see how much gain there will be.

If you consider to resin, you can sand it with water sandpaper and after that polish it for even smoother effect.

I know many people resin but i want to try something that can guarantee a consistent smooth surface such as sheeting.

It will be a long time before i do this for the install i want to do it for.

I'll go to Lowes tomorrow and look around and talk to them about it and see what else i can find out.

Why wouldnt a high gloss latex or enamel paint work?

it's not that it won't work.. it's the fact that since it is a liquid, it would be practically impossible to apply a liquid onto a flat surface PERFECTLY with no ripples or imperfections.

It would need to be sanded to make it smooth but even then can come imperfections by sanding too much in one area than another.

It's almost like i'm being OCD about it but in all seriousness, it needs to be level and smooth as hell.

There are many more things i will need to be doin research on inside of the enclosure but this is just one of them.

I was talkin to a buddy of mine of being able to run 8awg wire as speaker wire off the sub's terminals WITHOUT them being in the way of airflow at all.

An idea i had is to route out a trench in the walls of the enclosure and tuck them down into it then install this sheeting so the wires are visibly gone and out of sight.

I'm actually gonna be runnin dual runs of 8awg wire Pos and Neg to each sub. There will be adapters for them to fit because the wire runs are probably gonne be about 15ft long and the subs will be wired in a manner to accept up to 65A of current through the wire for competition and they will need the most wire possible to support this load with the least voltage loss from amp to sub.