From: bstdenis@mailbox.fwrdc.rtsg.mot.com (Brian St. Denis)
Subject: Re: subwoofers/boxes
Organization: Fort Worth Research and Development Center, Motorola, Inc.
Date: Wed, 30 Dec 1992 03:53:21 GMT

In article <1hsd8mINNc7h@rave.larc.nasa.gov> bell@hops.larc.nasa.gov (John Bell) writes:
>In article <1992Dec29.091615.20341@schbbs.mot.com> bstdenis@mailbox.fwrdc.rtsg.mot.com (Brian St. Denis) writes:
>>
>>I have a 12" MTX RTP woofer (2 voice coils, their top of the line, $110)
>>in a 1.6 cu. ft. box, vented.  The information that came with the woofer
>>says it should be 1.7 cu. ft. box, but otherwise it is exact to specs.
>>My buddy has a Petrus Prowler PZ 124, $130, in a 2 cu. ft. box, vented
>>according to his instructions.  I hooked my woofer and box up to his amp.
>>There is no competition, the Petrus is way better, way lower, way cleaner,
>>even louder.  My MTX even grounds out once in a while the Prowler woofer did
>>not even though it was producing much more bass.
>>
>>My question is can the difference in woofers make such a huge difference?
>
>You didn't mention the dimensions of the port in your box, so I 
>can only assume you built it according to MTX specs. A few weeks ago, there

The port is 7.1" long, 4" diameter like the spec says.

>was a nice article posted describing how to tune the port after you have
>built the box. Although you have some leeway in box volume, there is very
>little leeway in the dimensions of the port, so the tuning process can be
>very important and can make a significant difference.
>

I missed that post some how.  If someone has the article on tuning boxes,
pleaes e-mail it to me.  Thanks in advance.


>As far as the differences between drivers, you DO generally get what you pay
>for. Designing a good driver is an extremely complex compromise between

I went to a place here that primarily sold Rockford/Fosgate stuff.  They had
one listening room and many trophies around the entry room.  I told their
manager my dilema and he (a R/F dealer) said that there isn't that much
difference in the woofers and the the large companies like MTX, R/F, etc.
generally don't make sutff that "doesn't sound good."  Just his opinion.
He also does NOT use the Punch Pro series woofers in the competition cars
because they take too much power; he uses their middle line.

>competing design goals, and it takes money to figure out the best way to get
>what you want. I don't know the specs for the two drivers you mentioned, but
>if the Petra has higher power handling capacity, I certainly would expect it
>to sound better (all other thing being equal) if you have enough power.
>

I think both my MTX and the Petrus handle 200w peak.

>-----
>John Bell
>NASA Langley Research Center
>bell@hops.larc.nasa.gov
>

This same dealer said that I should go with an infinite baffle (sp?) 
instead of a box.  I have a Mustang notchback with a trunk.  He says
that would be better than having a good vented box of 2 cu. ft. or so.
How does an infinite baffle set up sound compared to a good box set up?
The price he said is $150 for the installation of the infinite baffle.
I can make a 2 cu. ft. box for $15 and a few hours of labor.  Also, a
box could be moved to a different car.

All I know for sure is that what my buddy has with his Petrus is WAY better
than what I have with my MTX and we spent the same give or take $40.

-Brian
"We like the cars, the cars that go ..."