rynberg

Damon, I know you know this but your wording above may mislead people.

The function of a port is to produce greater output at the port tuning frequency than the driver itself can generate. At the port tuning frequency, the air velocity slows down so much in the port that the driver cannot move. This is actually the DESIRED result! Below the tuning frequency, the velocity again increases and now the driver "unloads" and can more easily be driven to over-excursion. The driver will also experience a 24 dB/octave decrease in response. Many sub systems then apply a high pass filter below the port tuning to achieve an even faster roll-off.

Those facts make me seriously question a port tuning frequency of 32 Hz for a powerhouse woofer. I'm not a car audio expert though, and I rarely (essentially never) deal with ultra small room acoustics like are in a car cabin. Even with the large amount of "room gain" present in a car, it would seem like 32 Hz is a high tuning frequency to achieve very low extension. Then again, maybe the goal of this setup is just ultra-high SPL above 30 Hz, in which case, it probably is a good idea.

Ok, done rambling now.

HardHitter

iTrader: (4)

Looks good sonix, that must be a PITA to get into the car by yourself lol.

I just resined mine today and the weather sucks, so it's going to take a while for it to dry and then this week hopefully I'll get fiberglassing.

Pictures will be up in my thead once I can get them uploaded

sonix7

Its actually very light for the size that thing is. That is exactly what I wanted. of course this will have another top that contours the whole back trunk area. I am waiting on a plethra of stereo equipment and dampening material. Then its on. My system is complete soundstream, with an influx of MB Quart and Sony headunit and changer. I may replace the MB quarts with the Tarantula series components. They are rated at 200 watts for the 6.5's and they are identical to my 12. There are nice. Although I truely enjoy the musical qualities of the Quarts. Who has pics of a non bose FD rear 1/4 panels? I need to see what the speakers look like with the grill off. I have a bose FD and I am going to have to get custom in that location. I am also so debating changing the whole interior color from tan to gray or black, its just that the black doesn't compliment the CF accents like a different color, such as gunmetal gray or something. Damn now I am rambling, I guess its contageous Tyler!! LOL

sonix7

Oh **** I double posted. Disregard. we definately need a delete button.

HardHitter

iTrader: (4)

If you want your system to sound good, get that Sony head unit out of there asap please.

Head unit and amps/install are very important

Herblenny

iTrader: (13)

I agree with you rynberg. I don't think Jason is shooting for optimal sound quality for FD's. I'm guessing he's shooting how loud you can get.

Another solution for larger porting will be to actually build a port using MDF (slots). I personally don't like the sound of ports vs. sealed. By the way, I'm way way old shool. This is how I got into cars back in '91 with my toyota corolla and in '94 with my toyota celica convertible with 5 precision amps pushing 20 speakers running around 2000 peak watts. That was quite a bit back then (all Boston Pro mids and highs and JL 10W6s).

Anyhow, Looks good Jason!

sonix7

It sounds awesome I also have so much equalization in the car its not even funny. I have a variable in-dash 5 band Graphic EQ/Crossover from Soundstream not including the amp x-overs. I am searching high and low for an audio control ESP-2 or ESP-3. I remember what an amazing job that piece did for imaging. I got the Sony because it was (1) reasonably priced (2) has no face not buttons. (3) remote. What headunits are recommended for sound quality these days? I used to run eclispe back in the day and those were amazing. Phil I know your old school but 20 woofers is crazy in any school. LOL. I wish I could have had that massage me for a minute. I also favor sealed enclosures but this performs better with a port. I know.

Edit: Damn I am tired, I thought you said woofers, not speakers!! LOL Thats funny. I am running ten speakers and that is it. Should be nice I want both sound quality and SPL. Best of both

HardHitter

iTrader: (4)

Reasonable priced SQ decks are still in Eclipse's hands. The only reason why I didn't go with Eclipse is because they do not have a detatchable face. Right below that it would have to be Alpine or Pioneer. I have Alpine CDA-9855, 3 way x-over settings and 7 band eq, great deck.

Fd3BOOST

iTrader: (7)

Yea that fucked up split in the wood is looking awesome!! HAHA HA
Next time try predrilling the holes donkey! I don't know whats worse, your joints and cuts or your tuck and folds. Your suposed to cut and stretch the fabric! LOL

Sorry I am a restorer by trade and had to laugh a little. Your having fun and that is the important part.


Sweet cracked wood because you decided to just run that baby on in without a predilled hole.


This is better than that guy Boyd Coddington hires.
IN BIZARRO WORLD

sonix7

Thanx man, funny isn't it. I am sure things will turn out just fine. I drilled those holes and put those screws in and then I got a nail gun going. I replaced that beam and added a few more after that. Nobody's perfect so no harm no foul. If you know anything about fiberglass, when the resin cures with a material it becomes hard. I already stated that I use a fiberglass sauce to cover everything, plus sanding and smoothing. I also stapled the cloth down better before laying the resin. Plus after I vacuum bag the box do you think the cloth will be sticking up anywhere or if it will even matter. It will all become the structure of the box. Tell me about that, or did you think I was wrapping carpet around it? who's the donkey? I know full well what I am doing and how it will work, but thanx for that shot of haterade big guy!!

Fd3BOOST

iTrader: (7)

It's obvious your no professional and I was just pointing out. If you want to post your little projects on the internet don't get upset when someone who does **** like this for a living wants to poke fun at you.

sonix7

That's fine, I wanted to share my project with others and I never said I was a professional anything bro. I didn't say anything to you except "thanx". If you would have been a little more helpful and not so degrading, I may have received you a little better. Also I am not sure what you do for a living but if you knew anything about fiberglass, you would not have said anything. Do you know what the vacuum bagging process involves? Why don't you shed some light on what you would have done, instead of pointing out one flaw that I fixed. Be more constructive with your criticism or save it. I will keep doing what I am doing, I really could care less who likes or not, I am not making this for anyone but myself. I think that's who I will try and satisfy. Thanx again.

DamonB

Understood and agreed. But at the tuning frequency in your post cannot be overstressed. The port doesn't sit there and do nothing the rest of the time before magically appearing at the tuning frequency. The tuning frequency is the area where the port overwhelms the driver as far as acoustic output, but at all other frequencies air must still travel through the port and it's at all these other frequencies where the MOST air will be flowing through the port. Just because the port isn't providing much acoustic output does not mean it does not have air flowing through it and it is not contributing to control of the driver. If the port is restrictive to the driver you'll find that the calculated response doesn't equal the actual response, essentially because all the losses compound.

If the port is restrictive you get port noises as well as power compression which impedes cone motion at ALL frequencies, not just Fb. If one wants to go crazy they can do impedance curves at increasing power levels. If you see Fb keep rising as power is increased you've got power compression because the port is too small. As soon as you get power compression your transient response nosedives. This of course makes perfect sense; if the cone is impeded it can't do what it should be doing. This is quite common and is one reason why ported enclosures have the reputation of poorer transient response than sealed ones. Either of them done right is always better than either done wrong and ported enslosures are often done wrong as they're much easier to screw up.

Typically I've found compression not to be a big deal as the pipe noises always show up and bother me first. Again all of this is not too common a problem until you start dealing with big, high power, high excursion woofers.

DamonB

Car woofers are different from home audio woofers in that their natural low frequency rolloff is considerably higher. Once you put the auto woofer inside the small cabin and get all the room gain you get that low freq extension back.

Compared to home or commercial audio the tuning freq seems high but it's in fact high to counteract the designed in low frequency rolloff and when you put those two together inside a small space all is good. My sub sounds great in the car. I put it in the living room one night and couldn't believe how much output was gone! I don't just mean it wasn't loud, it wasn't there!

sonix7

wow good stuff DamonB!! Thanx for all the insightful info on the science of porting and all that.

Fd3BOOST

iTrader: (7)

I already said that I do this stuff all the time. I don't why you assume I don't understand how to cure under vacum. It's not a new concept. Putting it under vacum is not going to correct your mistakes. Your box still has flaws that a vacum cure wont fix. The case is built poorly, the fabric is layed wrong, the corners are cut wrong and I could go on but I won't. I did not post my work on here for a critic, you on the other hand did so at least be open to.

Look you wanted constructive critisism so here you go. Do yourself a favor and read a book. That would at least explain to you how to properly cut and lay the fabric for integrity. http://www.amazon.com/gp/product/186...lance&n=283155

I won't suggest a book on building the cabinet or general carpentry. I've been doing tha crap so long I wouldn't even know where to start and most of what I know I learned from my old man and being a restorer for the past twelve years.

Sorry if I pissed you off but again you have to realize that there are people on here that are going to see some of this stuff and laugh just because to a professional sometimes amatuer stuff is laughable. I am sure that my photoshop would look like a joke to someone who does it for a living etc. So please undertsand it ain't personal man. I had a beer or two and stumbled into this thread and found myself laughing out loud and posted. Sorry and Good luck.

sonix7

Not a problem boost, I don't build boxes for a living and have not done so in years. I make sure the CF I lay looks perfect and that is my thing. I am always willing to better myself in order to do things right. Your suggestions were absolutely right, I appreciate the insite. I however did the best plan I could come up with in my head. I guess evolution of ideas always play out different in each and everyones own minds. I like the difference in techniques and ideas and opinions it keeps things real. I never feel or think I know everything or do the best, but I try real hard in both areas. FD3Boost me and you are cool, maybe one day we can have a beer together, or better yet a cocktail. I like my Maker's Mark. If you want to give me some pointers and tips shoot me a PM anytime.

tidbit

welcome to the world of custom enclosures.. I'm sure you will learn quite a bit from this install... I know I did when I did my first.. gl with the install.. and make sure to post up followup pics...

speaking of.. I need to get back to mine


oh a tip... i will normally only use one layer of fleece (white pref)... and then lay up some matt on the inside/outside.. the fleece weave isn't as strong as matt or the like..

John64

Do research here, then come back young Jedi!
http://www.the12volt.com/installbay/...ics.asp?FID=16

sonix7

thanx for all the help guys. I have done plenty of enclosures and installs just not in a number of years and definately not as complex as this one. I will say it again. I use a chopped mat strand resin sauce. It is like stranded FG mat all chopped up. I add that to the resin of the next layer after I have wet out the fleece. Then I build and sand to perfection, I am not sure what is wrong with that process? It just saves me time, instead of wetting up a stranded mat onto the box, I just reinforce with the resin sauce. I also have a fairing compound that I can add to my resin for strength. No way was I using fleece all the way. That is just to stretch and get the shape I wanted. The astethetics of the actual box has no bearing on the final outcome of the install. There will be a seperate top to it that will be wrapped in CF. You will never see the actual box itself anyway. So we will see how it comes along.

sonix7

Ok here it is at the first layer of glass on top. I plan to reinforce it until its strong. I also have been reading over at 12volt.com (thanx for the link) and it kind of backed up that I did this right. This is a basic concept and though somethings could have been cleaner, this box will be a winner.

HardHitter

iTrader: (4)

Looks good man, looks like you're having more luck that me, this is where I'm at right now



I need to finish bondo'ing and then I need to add some more fiberglass on the inside cause there was a spot where fiberglass wasn't building up on the resin :-(

sonix7

HH your doing your thing, nice job man, I guarantee we will both be happy with these enclosures. Did you use straight bondo or did you do a mixture of bondo and resin? it looks like a volcano right now huh? LOL. about ready to errupt with bass!

HardHitter

iTrader: (4)

Yeh there are a few things I need to work on.

What I did was made a body filler/resin mix basically a 5:2 ratio and just painted it on. This was a lot easier to fill in the lows and get a smoother surface. Once I have that setup, I go over it with 80grit and sand it down to find the rest of my lows/hi's and then most likely re-bondo again. There is a wrinkle that I need to bondo to make it smooth out so I still have a lot of work. I also need to fiberglass like I said from the inside because one of the parts isn't connected.

Lots of work, it will hopefully be worth it!

John64

Hey you ripped off my project! Well I guess thats why I posted it up. Good luck with it. Do you have any build pictures??

John