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Re: Some audio answers (archive)

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Posted by Bob Hazelwood on January 15, 1999 at 15:40:54:

In Reply to: Re: Aftermarket Audio for E39? - Crappy sub posted by Bob Hazelwood on January 11, 1999 at 16:35:47:

Sorry I'm a few days late. There was more piled up while I was away than I expected.
While I have not seen the E39 sub in person, what was described to me by those who have appears to be of very limited worth. The enclosure is limited as to what it can handle without flexing and rattles, so that upgrading the drivers will be of limited use. It sounds similar to what is in the Z3. I have one of those here and have been "pulling my hair out" (those who have met me know this is literally impossible - I have no stinkin' hair!)for two months trying to come up with a driver replacement which doesn't simply trade one problem for another.
A better use of the money will be to replace the woofer enclosure. If maintaining trunk space is a priority, an 8" woofer made to work in a small enclosure will be much better than the factory box. The a/d/s/ 308rs, built into a .35 to .5 cubic foot enclosure will provide a meaningful performance improvement without taking up too much space. If you don't mind devoting a little more space to the cause, the 310rs works well in a .65 to 1.0 cu.ft.sealed box. Both the above models are DVC. Other brands such as JL audio and Kicker Solobaric series have similar products if you don't have an a/d/s/ dealer locally. Any good high-end car audio shop should be able to fabricate something which fits the contours well in the trunk area.
For those of you who wish to keep the factory amp and main speakers intact, it is a crap-shoot as to whether the resulting bass level will match well with the factory amp driving the new woofers. It may be OK, but for the optimum performance, my suggestion is to add a dedicated subwoofer amp to the existing system. If your'e adding a sub to a non DSP equipped vehicle the signal to drive the sub amp can be taken at the input signal from the deck to the factory amp. On a DSP equipped vehicle you will have to use the factory amp's sub output, unless you are replacing it, at which point you can tap the signal between the radio and amp also. On the DSP cars, there are only two channels of audio available bteween the radio and the amp since the rear channel functions come from the DSP box. That's OK though, since that's all you really need for this. A P240 or similarly powered amp is about right to match the factory amp and speakers.
By the way, if anybody on this board is in the Boston area and plans on coming to the Tech Session at Rich's Car Tunes on Feb 18th, I'd love the opportunity to take a look at your car for a few minutes before or after the meeting so that I can speak with more comfort that I really know what I am talking about. I've got plenty of E30, E34, and E36 experience but my E39 knowledge mostly comes courtesy of others.

Best regards,
Bob Hazelwood

:I return on Wednesday and will respond more intelligently then. Stay tuned.

: Best regards,
: Bob Hazelwood
: VP Product Management, a/d/s/
: '93 525i 5-sp, Sharked, BL/ss'd, etc.

: :

: : To Bob Hazelwood: Is there any chance of improving this sub-woofer unit by replacing the 4" DVC drivers and leaving everything else intact? Or maybe the thing to do would be to ditch the entire thing and build a new enclosure around your 310rs speakers. Do you have any application notes on enclosure design for your subs?

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