Any pics you could post of the quick in and out of the subs in the rear foot wells would be great. Time permitting of course.

Cheers from the Low Country of S.C.

 

Sorry to resurrect such an old topic, but I am in the process of planning the Rod Birch install.

Is there an issue with screwing the enclosures into the sheet metal with a self tapping screw, ie. rust, etc?

Boris, did you ever take the pictures?

 

I just got through installing the Rod Birch set-up. Confirming previous posts, Rod is a real pro, and a nice guy too. Subwoofers do take up at least an inch of rear travel in the seats. I am 6'2" and miss that inch of legroom, and would take out the drivers sub for a long trip. The quick disconnect sounds like a neat idea. Maybe Rod can incorporate it into his design. Would be worth asking him.

 

Realizing that this is likely to be a unpopular opinion, I must first ask what is the primary motivation for utilizing a SW in a otherwise ordinary car audio system? Unless one has unlimited resources, designing any car system will require major compromises. This involves the number of speakers, power availability, and enclosure size. If the acoustic ideal is to produce a sound with the flattest possible frequency response, the basic principles and interplay between these variables cannot be ignored. One oftens ends up powering a limited frequency band perhaps sounding OK with some types of music but usually inadequate to produce a musical non- directional low end.

If you already have a decently designed and powered front end and you now desire to add depth and frequency extension with a SW, keep in mind that you will need enough additional power( a second dedicated amp is ideal) and must have the proper enclosure. This has been discussed in the past and the agreement among audiophiles here is that an unsealed baffled SW enclosure can not truly produce a non-directional musical low end from 20-70hz.
The smallest possible enclosure will be sealed(forget about ported!) with a volume tuned and specified by the manufacturer. To get an idea how large these "small" boxes can be, after extensive research I am currently having built a 1sq.ft. enclosure for my Mercedes. This is for a single Phase Linear 12" Aliante which has the smallest footprint and enclosure size requirement I could find.

There really is not enough room in a Porsche for an inconspicuosly placed sealed box. After beating myself up over this reality last year, I decided to go with a 3-way system with an 8" mid-bass in the door and the midrange and tweeter in custom kick panels. It is powered with a single 265W Brax amp and equalized by 1/3 octave dual channel EQs tuned on an RTA. The resultant frequency response is flat with a soft roll-off at around 45hz. The strength of the system is the imaging and most people would not feel that the lack of a SW to be relevant.

Again, I am sure this is not the majority opinion here but just thought I pass on what I have recently learned (expensively!) to those who take their music as seriously as their driving.

 

Dr Z, I take what you say, and I have worked in the music industry on and off, and have some experience of PA systems and studio pro audio. Although I admit that I forget the physics behind most of it, but I do appreciate good quality audio when i hear it. However in this instance my resources are fairly limited and I like to listen to house music.


I have upgraded my cars speakers with 6" Focal Access 165 CA's in the front and MB Quart Discuss coaxials in the rear, I have installed an uprated head unit which has a 4 x 50 Watt amp, and the improvement is vast, but I know that an amp will help to get the best out of my speakers as the head unit is only 4 x 50 W peak, not normal power. I would also like to get a bit more bass, and Rod's enclosures are the best solution I have found for the money., while retaining something of a stock look.

I am however always interested in other options if you could give some details on what you have done.

I must ask the question again as it is my biggest concern, Is there an issue with screwing the enclosures into the sheet metal with a self tapping screw, ie. rust, etc?

 

There is a great free website: www.bcae1.com/ that has all one needs to know and more about car audio. A great reference for those who want to better understand the physics and electrical relationships necessary to install a great sounding audio system. Provides an unbiased primer on many topics as well as very cool graphics and useful calculators for the DIYers.

My system is quite involved, very stealth and not inexpensive. It required expert installation not easily available or attainable in every city. I can wholeheartedly recommend Peter Lufrano (TheAutophile.com) from the Bay area as a invaluable resource for designing hi-end systems. He is the sole US distributor for Brax/Helix and Phase Linear. He is very knowlegible as well as accessible for answering car audio related questions. He can also refer you to installers who carry Brax products. Even if you choose gear which is less esoteric, these shops should be a good starting point because if they know about Brax they should be proficient in Alpine, Eclipse, Nak etc.

 

I have been looking at www.bcae1.com, for a while and it is a wealth of information, a really good site for refeshing my knowladge of the involved physics, so much information that my head now hurts!

I just want some practical advice on what amp to use and which subs are suitable, and I think that Rod Birch's sloution and advice so far seems to me the one for me, I think I am going to power all my speakers from an amp, but I am not sure if the rears can be driven to produce much more with an amp than by my head unit. I really want some stealthy subs and his enclosures look the best. I just get a bit confused by all the conflicting advice.

 

Hey Dr Z - What kind of stuff do you run in your house ?

 

Agro, funny you should ask! Prior to getting in way over my head and budget with the Porsche, I had not updated my home gear in over twenty years. Considering that I already owned some nice vintage stuff and finding that my car sounded so much better, I recently have gone the upgrade route after becoming a student of Audiogon.com for several months.

I subsequently decided to have my ancient Dahlquist DQ-10s rebuilt by Regnar in NY and just recently sent them my DQ-LP1 electronic filter to have upgraded and re capped as well. I am driving the mains with my original Mcintosh MC2255 amp and a single DQ-W1 SW with a 400w Carver cube that I had laying around. The source unit is a Resolution Audio CD-55 plugged directly into the amp which I picked up used on Audiogon. I have gone with Acoustic Zen wires for the most part.

System is very nice but I will probably want to start all over one day when I get around to setting up a home theatre. The Porsche system is a keeper however, and considering that the car has only 18K miles and will be something I hold onto forever, hopefully the stereo investment will eventually pay for itself in the long run.

 

Sounds very nice indeed. How'd I know you had a MS2255 Sweet smooth sound with the cube. I'm sure the 993 stereo pays for itself everytime you turn it on. Take care, and enjoy. BTW, audiogon is great huh ?