hans14914

*Update on post 50*

Fellow Rennlisters,

Some of you know I have been working on a drop-in speaker system for the 1984 and newer 928's. I have gone through all the available drivers out there, and even had a couple drivers built for testing purposes. I have not found a driver that I am absolutely thrilled about to date. I have recently located some European drivers, not currently available in the states, and will be receiving some samples soon for testing. In the meantime, I have been investigating having custom drivers produced.

I have found a build-house who makes some of the best car audio drivers in the world, and they are willing to do a custom run for me. These drivers would be a dedicated 4" midbass driver that would fit in the factory location, and not require any form of adapter or spacer. Not only would these be a perfect fit, but they would be purpose built to be the best acoustical option for the 928, operating from the low 100hz region (F3 not to exceed 120hz) to 3khz with authority. Suggested application would be a minimum high-pass of 12db at 125hz and maximum low-pass at 2.5khz at 12db.

In short, these would blend perfectly with a subwoofer to provide a strong front stage (without requiring adding a second driver in the door as some listers have had to do in the past) and play high-enough to work with the increasingly common wide-range tweeters available today.

I am curious if there is a large enough market to place an order for these drivers. There would be significant upfront personal costs to get these drivers manufactured, so please answer the pole honestly. This isnt the only option, but it will certainly be the best option available without custom enclosures and severe modification to the car. Again, please vote honestly, and select the maximum price at which you would *actually* pay. Please also feel free to post comments in the thread.

Thanks
Hans

danglerb

This would just be for the 84+ grille cars?

My "speaker" car is a US 83 before the change to round grilles in I think 84, so I didn't vote. My search was not exhaustive, but it did cover all the common sources and I found maybe 4 likely speaker options for the early cars, and didn't look for anything for newer models.

Rebuilding the factory drivers with rubber surrounds is a viable option as well.

I ended up using a pair of 3.5" Alpine drivers in each door, and the sound is good, but I think if doing it again I would take an entirely different approach and skip speakers in the doors entirely.

bronto

I don't think your location exists in my '79. I have a z-box (928 specific) subwoofer in place of my toolbox, with Blaupunkt component speakers in the rear quarters and doors. Someday I'll get around to seeing what it would take to reproduce the z-box....

hans14914

This is for the 84+ cars. If I had an 83 or older driver, I could see if it would fit this application. I will update the first post to clarify that, and thank you for reminding me.

Bronto - I have a solution to the Z-Box issue, will be posting about it soon. However, I do have access to a composite shop and could reproduce that part if you need another one.

Thanks,
Hans

Tom in Austin

I haven't been able to find any speaker shallow enough for my door openings. I think about 1.25" depth is all that will fit ... other 928ers say 1.625" will work but for some reason my car needs a truly shallow speaker.

hans14914

Tom,

That is the problem for all our cars. There are a couple options out there that will fit, but:

A) they sound terrible
B) they will not fit under the factory grill
C) they are expensive ($100+ each driver)
D) only available in 8ohm impedance

I have found some new drivers not currently available in the states which show some promise. I have not auditioned them yet, but the manufacturer is sending samples, and if they work out, I will not proceed with the custom drivers. However, I am continuing to do my due diligence on the custom route.

Thanks,
Hans

bronto

No, I don't need another z-box, just thinking that others might want something like it. But if you have something coming, that's good news.

86shark928

I have and 86.5 and I went with Alpine Type R speakers and used the factory speaker grills.

karl ruiter

I've been thinking about redoing the sound system in my '88, but I am kind of a audio noob. I was thinking about the Infinity Reference series because I like the efficienty/sesitivity numbers. In the past I have purchased speakers that had high power ratings, only to find that, while you could pump that much power into them without blowing them up, that did not mean they would do a good job of converting that power into sound at all. I assume from what I see here that the infinity reference would not fit. So, a couple of questions about your proposal:
-Is there any way to get efficiency numbers or estimates for the final product? Is this the number I should be looking at?
-Could these be used for the rear speakers (under the hatch) as well? I think they are 4" also.
-My stock grills were long gone when I got the car. Any grill solutions to go with your drivers?
-What kind of time frame do you think we would be looking at. If the customs are a year out, I will have already done something.
Thanks.

S4ordie

Hans - as you know I am a total noob-neophyte when it comes to audio. After lots of fits a mis-starts I'm ready for a fully tested/integrated system that will be a drop in replacement for the stock system. I want to maintain the the stock look but have 21st Century sound without having to build or use a visually obvious sub woofer / amp box. Your in the spare tire solution is a good one.

Drop in with pre-cut wiring and detailed connection instructions for a great audio system - I'm in.

bronto

Oh, spare tire subwoofer. Not what I'd be interested in. S4ordie, the z-box has a totally integrated look that appears like an OEM accessory. Totally fits in with the contours of the interior. My understanding is that Porsche offered such a thing as an option for a few years, dropped it, then Z-box offered it for a few years. There is a two cone model I've seen in someone's at Sharktoberfest, and I have a single cone model. There are both leather and vinyl covered models to match your interior.

hans14914

The drivers I am working will be high-efficiency, no less than 88db. I do have a grill that fits and looks good. I would not recommend installing speakers in the rear hatch, not only do they add expense and complexity to the system, but they actually hurt the overall performance of the system.

Custom drivers do take time. I have been told that it will be 90 days from approval till they are ready to ship, it would be a long process, in the order of 4 months. That is why I want do double check and see if there are enough potential buyers.

As far as output, these will be able to handle around 50w or so of pure power (not filtered through a passive crossover). The design goal is to achieve 105db output from a 30w amp, so these will get plenty loud, even with a compact amp.

I am going to leave this thread up/active for about a week and see what happens, if there is not a lot of interest, then I will start offering the lesser performing European driver, as they are ready to go.

Thanks,
Hans

SeanR

I am interested in the rear 6.5 and sub set up when you guys finish that .

I used the high end MB Quartz for my fronts so happy on that account.

Ketchmi

For later cars I have been putting these sets in and they seem to be working out exceptionally well. Hertz HSK 163. They are under the "Hi Energy" tab, "system" then "HSK 163" if the link doesn't get you there. It takes a little imagination to use the factory grills but it can be done. This speaker system run by a bridged Memphis MCA 2004 (mounted in the passenger side parcel shelf) and one of our subwoofer boxes with a single 10" DVC (400+ watt RMS capability, dual 4 ohm, a good one!) with a Memphis MCD 500 will blow you right out of the car while still being extremely clear and distortion free if tuned properly. Not exactly cheap but very high quality for the price. It is pretty well hidden and you can build a panel to cover the front amp, no-one will know what's up.

http://www.hertzaudiovideo.com/Doc/H...rgy_HSK163.pdf

hacker-pschorr

A quality 4x6 that fits the 78-83 cars would be great!!

Why must you always forget about the early cars???