Contour Enthusiasts Group Archives Forums Modifications Audio help wit wiring and DVC's ect.

BTW, "loudness" comes from 4 things in-car.

1. The effeciency of the enclosure.
2. The power handling of the system
2. The power supplied to the system
3. Cabin Gain

The cabin gain will vary by freq.

on the site (ddaudio) they talk about vented box but when i go to box design they talk about ported boxes and different sizes then they recommend. are these 2 different types of boxes?

i woudl like to get the largest vented box that they recommend for the sub (4ft internal volume i think is the largest they estimate i werked some numbers out and i came up with 3.9$#@ dont remember the exact number)... i was priced at a local place 300-600 per box. i have NO experience with vented boxes how much they cost ect. now ima go to the person that makes all my boxes and see how much he charges im sure it will be less. but if not should i change the style of the box?

ya need that software to test wut frequency ya get the most cabin gain at? or is there another way to do it?

also no1 told me about the price of the subs if im gettin ripped or not.. the guy at the local place (not where i usually go) never heard of mmats or DD. heh

also thanx for the replies

im confused

-afr0

[This message has been edited by loudest_contour (edited October 19, 2000).]

There are basically 4 types of enclosures for subs
1. vented/ported/PR
2. Sealed (acoustic suspension)
3. Bandpass
4. Transmission Line.

Sealed boxes are far and away the easiest boxes to design. They normally have deeper bass at the cost of a little output.

Vented/Ported (the same) are louder at lower freq. but the sound rolls off quicker than a sealed design. A PR acts essentailly the same as a port with a couple of advantages, you won't get wind noise from the port and they are typically 1 dB louder at the tuning freq. than a ported design. The noise factor in car is not really a factor with trunk mounting. PRs are very hard to tune. Ported boxes are also somewhat difficult to do right but with a little experimenting, you should be able to get it right. If you can get me the factory specs, I would be happy to tell you how big of a port and how long it should be.

Bandpass subs are ok for car use. They act as a natural crossover for the driver (you still need an actual crossover) and they tend to be louder than other variations. Their downfall is large enclosures and they tend to make every bass note sound the same.

Transmission Line subs are extremely nice but not practical because of the size needed.

4 cubic feet is huge!!! especially when you get two of them!! Do they recommend only ported?

------------------
99 SVT
Sony ES CDX-C910
Sony Digital EQ/X-over
Sony Changer
McIntosh MC440M
Adire Audio Shiva
MB Quart/Vifa seperates

www.ddaudio.com
please go there if you click on drivers then 9500 and look at the spec. sheet
vented 2 - 4 ft
or sealed
then click enclosure & port specs then click SPL 12" then it tells you a different box to use?

i have no clue which stats to use. PLEASE HELP!!!!


damn site is confusing as hell

-afr0

I would highly recommend not using the SPL design for the box. Your bass will sound like (i'm trying to think of the worst thing in the world but can't think of anything bad enough to describe it).

By the way, your Perfect 12's will actually be louder than the DD subs with the 1000 watts you are providing. The sensitiviy is 89.5 db 2 volts/1m. This sub would require two times as much amplifier as your Perfect 12 to acheive the same out put level.

When you look at the graphs on the website for the SPL you will notice a big spike in the response at 50 hz. This will cause every bass note your stereo plays to sound the same. The goal should be a flat response, you can get tremendous bass and still get good SQ.

I would recommend that you stay away from DD if SQ means anything to you. I can send you some graphs that will predict the response. It may help show what i mean. what is your e-mail address?

dnewma04 -
I have been off the forums for a while and I am looking at what you have in your car. REALLY NICE. Do you have any pictures of your setup?

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David Litsky
96 Contour GL
Clarion, Infinity, ESX, Alumapro
"It is stupid to argue with idiots because you stoop down to their level and they beat you to death with experience"

Thanks David L,

Sorry to report that there are no pictures yet. I have only had it in my car for about 18 months, don't rush me! :-)

The reason I've got the stuff I do is because I always tried to get the best quality I could find for the money and it tends to keep it's value. My last car had 3 precision power amps, 2 A300s and one A600. The sound was wonderful but then I found the McIntosh amp and I just had to have it. Sold the PPIs bought the McIntosh amp and I couldn't be happier. I also discovered about a year ago how much money I could save by getting DIY home speakers and using them in car. Better quality, better sound, i wouldn't buy another brand name sub or component set.

Anyway, I'll see if can get some pics taken and post them.

Dave

i disagree with ur statement about which would be louder (perfects) the box will be a lot bigger and also a different style which i thought impacts the SPL? i could be wrong im just goin on wut the replies are. also i need help with the cabin gain idea. tools and stuff to find the frequencies ect...
dont care much bout SQ need high SPL scores win some comps prove that a contour can win ;]


-afr0

Send me your e-mail address and I will send you some pictures and charts to show you what i'm talking about. davidnewman@excite.com

jwomurdock@aol.com