Replies (8)
ShootuhMcBustaCap on 12/14/2006 19:34:20
Ok Here it goes. So I need to build a pair of custom enclosures for a 98 Civic Coupe. These enclosures are to be for a pair of MB Quart RWE 304 12 inch subs.
The help I need is as follows: I need internal dimensions of the box, as well as the slotted port neccesarry to tune these beasts to 25hz. Also need to know how to calculate port and subwoofer displacements so I can build the proper size box for these.
I do not have sub measurements right now, but I can easily get these.
Theile/ Small Parameters are as follows:
Re: 6.7
Qms: 8.50
Qes: .75
Qts: .69
FS: 33 Hz
Vas:41.5
Impendance: 4 ohm DVC
I do not have any of the decriptions of what thes numbers mean, the owners manual for these subs are in any language but English, but I could tell you what they all are in German, French, Russian, Spanish, or Italian if that helps. LOL........
Any help would be great, I've only built one enclosure before, and it was BP with all the specs right there in the manual, and all displacements compensated for. I need these specs, this job is the first customer i've had in like 3 months, and the only work I have right now.
Thanks guys
cplkittle on 12/14/2006 19:58:29
so you need 2 boxes.. what are the size restrictions? Is this a hatchback by any chance? What is the max height, length width.. etc.. you can tune a 1cu ft box to 25 Hz, but the port would be 50 feet long (not literaly).. the bigger the box, the shorter the port.
One thing.. this is a small car, I would suggest you tune it to more like 34-38Hz. 25 is not going to respond well especially if it is in a trunk.
ShootuhMcBustaCap on 12/14/2006 20:12:05
Ok thanks. I will have to talk to my customer about that. I don't think size is a big issue though, but I will find out for sure.
The vehicle is a 2 door coupe, not the hatchback, and subs will be in the trunk, I trust you on this tuning note, so I'll shoot for like 32-35 in here, my customer is wild for deep bass, so thats why I was thinking the 25 hz range.
He does want two seperate boxes, firing foward each on opposing sides of the car, as close to the rear as possible. Seats will be folded down to alow a little more bass response.
cplkittle on 12/14/2006 20:20:09
I'll figure something out and then you measure it and tell me if it will work.. gimme about an hour.
ShootuhMcBustaCap on 12/14/2006 20:29:05
Actually hold your cannons for a minute on this one, I need to get trunk all measured out.
cplkittle on 12/14/2006 20:58:35
OK, tell me if 14 tall x 14 deep x 18 wide will work.
If it will the internal volume is 1.67 cu ft. tuned to 34Hz with a slotted port of 13.25" (internal height) x 1.5" wide x 24" long (this means you will have to make a turn inside the box with the port).
If it can be bigger, I can shorten the port and tune it a little lower.
If they were both in the same box it would be ALOT easier. but ya gotta do what the customer wants.
ShootuhMcBustaCap on 12/14/2006 21:51:18
Unfortunely yes we do have to do what he says. Damn shame this is going into a Honda too, definetly not my brand preference. Wouldn't we still need to compensate for the sub's displacement. This is a pretty massive sub, and It will displace a ton of room.
I am going to try to convince him to go with a single enclosure, but with a seperate wall to divide the subs. He wants the seperate boxes because he wants this vehicle to be a show car, and somehow he thinks this will increase this value.
I guess I need to talk to this guy some more to get this figured out. He has had us waiting for like 2 months now, I'm ready to do this already. If it was my car, I already would have put it in, got bored with it, and replaced it, but he is the one with all the money.......
swez on 12/15/2006 19:16:38
This is a process of negotiating a balance between optimal performance and making things fit. Better to do all the details up front and explain to your client what options are in his best interest and still something you can build to satisfy his needs, (Paying customers need education) and you'll have to lead him through something that makes sense in the end.
Also, this may be a very tight fit and using dual boxes are probably a good option. (Easier to build and load into his vehicle) That makes sense.
Also, if doing opposing sub designs, phase cancellation must be taken into consideration. Somethimes, it's a simple matter of wiring each sub so they are 180 degrees out of phase. (Push/pull cone type install) However, a vortex type placement may be the best option here. The subs are loaded in such a way so that the subs are loaded in a "V" shaped layout, aimed to the rear of the vehicle.
This allows the subs to remain wired in phase and the energy from both subs combine at a given focal point in the back of this car.
In short, educate your customer and if he wants the sun, moon and stars, but you're not sure you can deliver that, best to walk away now, then do the work and have it turn out poorly and you don't get paid. People in Hell want icewater too. But that does not mean we can deliver it. (BTDT... it's usually a lose/lose proposition)
Proceed with extreme caution OK? Don't get burned because of someone elses "unrealistc" expectations.
Swez
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