hans14914

I have the second-generation prototypes in my hands, and hope to have a chance to audition them tonight. On paper, these are by far the most impressive 4" mid-bass drivers I have ever seen. They have solid performance down to around 100hz, and are almost ruler flat out to 5khz... all in a package slim enough to fit in the factory 928 door with no modification of any kind.

To compliment the driver, I have just authorized production of a custom stock-looking grill. It will match the other 928 grills and interior very well, but will use a 2-piece construction where the metal grill is the removable part, so it will hold up much better than the factory part. I am also planning making the grill compatible with the factory driver, or commissioning a second set of tools to make a factory replacement grill.

Also in the works is a replacement stock-look tweeter grill for the Vifa (or possibly custom) tweeter options I have lined up. Again, I will try and make these in a way that can replace the factory part for those with tired grills.

Lastly, I have drawings of a slim 6.5" driver with matching carbon fiber cone and motor assembly for the rear location. It comes in shorter than the factory driver at 62mm, and will be perfect for custom install in other tight locations - like in the front doors if desired. The build house is currently making prototypes of this driver for evaluation as well.

There is lots going on, but I should have several set of pre-production drivers available to send out in the community for independent third-party evaluation. Delivery of drivers will be in approximately 90 days from order (which should take place towards the end of this week). I will open up a pre-order soon.

If you are in the market for speakers, these are the ones you want. The closest "competitor" will be the Focal Polyglass 100VRS... which will cost much more, and perform less.

Thanks
Hans

Tom in Austin

Interesting, glad you're thinking of a full set to all the old ones at once.

Tony

I wouldnt use grills if they looked like that!

hans14914

Alright Gents,

I have placed a deposit on manufacturing these drivers. So these will happen. I can confirm at this point that we will have 928 specific 4" speakers, custom grills for both door drivers which will match each other, and be very discrete (similar to the aesthetic of the factory grills). Deposits have been placed on all the above and they are in the process of being produced now.

I am going to build a custom crossover for these drivers and the .75" Vifa NE series tweeters. A kit will be available with a pair of custom 4" drivers, pair of Vifa tweeters, custom 928-tuned crossovers, 2 pairs of grills, adapters for the tweeters.

Everything will bolt in using factory mounting points, requiring no permanent modification to your 928. Everything can be returned back to stock very easily, allowing you to maintain a high resale value for both your 928 and the components themselves.

I will be able to post pricing as soon as i determine my costs associated with the crossovers. These will not be standard/generic filters, as I will be using the frequency repsonse plots taken from drivers installed in a 928 door. These will be tuned exclusively for the 928.

My goal is to keep the price as affordable as possible, and it will be comparable to any other high/mid-end mainstream component set (think MBQ retail pricing). This will be considerably less than the only current component set which fits, the Focal 100VRS, and will perform many times better.

I will open a pre-order thread as soon as I have the crossovers done. There will discount opportunities with the pre-order, and also as a package deal with the SharkWoofer system.

Further derivatives will be available employing active filters and biamping for top-level performance. The active filters will come pre-loaded with the correct time alignment, eq, level matching, and crossover points for a standard 928 driving position, but will be able to be further customized with included software and a laptop.

A matching 6.5" driver is currently be evaluated. I am not sure if it will go into production at this point. My original goal was to create a system which was properly balanced to allow most of the factory speaker positions to be "deleted". The extra drivers, especially the ones in the hatch of the 928 not only are excessive, and represent an overall draw on the system power while adding wiring complexity, but also DECREASE the overall level of performance. The drivers located directly behind the front seats in the rear quarters are not as deleterious to performance, but they certainly are not required, and beyond that, there really is no need to have a component set (both midbass and tweeter) in that location.

I am planning (auditioning, tuning, critical evaluation all yet to be performed) on recommending that customers simplify their system, by running less drivers and implementing better practices and tuning tools. The overall cost of the installation will be less, as there will be significantly reduced component count, wiring, and labor. Each individual component will cost a bit more, but will work work cohesively as a set and offer the best possible configuration utilizing the stock locations and without requiring damaging modifications to your 928.

Keep an eye out for the new sale thread to be posted in the coming week(s).

I will also be posting more about the 4" drivers and the partner who helped develop the driver on this thread shortly.

Thanks,
Hans

hans14914

I have some updates on the 4" driver as well as the the potential 6.5" version.

We (partner on the project soon to be announced) have been working on the 4" driver since late fall last year, and have now gone through several revisions. A couple weeks ago, I requested that we include a copper shorting ring in the motor to lower the overall inductance and flatten the impedance curve. The original goal of the driver was to be a solid mid-bass performer, however after looking at several of the plots it was clear this driver could be much more with a little additional tweaking. Samples are on the way, but I received plots last night which I have to share.

Please notice that these are unsmoothed, raw exports from the measurement system - no marketing tricks or gimmicks. If you compare these to plots from other drivers, please keep in mind that they likely have applied several smoothing filters (its like a dyno correction factor, you can dial in anything you want to get impressive numbers). The nice thing about the audio industry is that most of the dynos are the same, with LMS being the mainstream standard, but that smoothing filter can be applied after the measurements. I will post some "adjusted" plots soon so you can see what industry standard smoothing does to a raw plot.

Anyhow, take a look at the low end response we are getting from this driver on an open baffle. It is pretty impressive. The F0 has shifted higher, but the peak itself is considerably lower, allowing for a very smooth rolloff well below the resonant frequency. I was surprised to see this too, so dont look at the F0 number out of context as it is higher than what I would want as well, but the frequency response is much improved over previous versions with much lower F0 points. Also, notice that the impedance remains almost ruler flat throughout the entire usable range. That bump at 5k will flatten out in our application, as higher frequencies diminish quickly off-axis. So in the stock location, the in-car performance will likely be near flat from 120hz through 5khz. The sensitivity for the driver has also improved 0.5 points, and is nominally 88db 1w/1m efficient. In the proposed installation with the XR-5S amp suggested for SharkWoofer use, this will yield a maximum non-cabin-gain-adjusted (will be higher because of the enclosed cabin amplification) of approximately 112db... which is darn loud.

The samples for a matching 6.5" driver are being built now. They have been assembled, but not tested yet. I am attaching some pictures of the driver for your reference. I am not sure if these will go into production yet or not, but they are slim like the 4" driver to fit in challenging locations, and can fit without any spacers within the factory rear grill/mount.

Thanks,
Hans

Chuck Schreiber

Hans,

Not sure what all the above means, but as long as it sounds good, I'm impressed!

Sorry if I've forgotten some details in the earlier part of this thread, but will the 4 inch take the place of the 4inch plus the 1 inch tweeter? Meaning, when I dissasemble the door panel, replace with one of these 4 inch speakers, can I leave the 1 inch there only hook up the 4 inch?

Also, I have a later model head unit driving all speakers in the car right now.
"High Power" unit. (Yeah, whatever) Will there be a crossover to go with this driver or what?

The previous owner installed some Boston's in place of the 6.5 rears with stock grills. The mids and tweets in the rear are disabled as well. Sounds good, but need new front speakers (yours?") and will add a small amp and shark woofer later.

That's the plan anyway.

Jon B.

I'm in for a set. Thanks for all the work Hans!

hans14914

Chuck,

It woudl not be advised to run this driver without a tweeter. I will be selling a kit with the crossover and matching tweeters, so you will be able to use your headunit if you want. This driver is not designed to be full range. There are some smaller 3" format drivers out there that will work for that application, but will have limited bass response, and also limited overall SPL (volume/loudness).

The tweeters that I will be including are fairly inexpensive, but very high quality. It will certainly be worth the expense.

Everything will come with matching grills, so you will be good to go with near stock cosmetics.

Thanks
Hans

stolarzj

I was just looking at the Focal's, so I'm in. I'm also interested in some 6.5's for the speakers behind the seat. Everything in my 86.5 is the way it left the factory, so it's needing a upgrade.

pcar928fan

Are there currently any good replacements for the early style door speakers? Mine in EURO85 sound like crap and w/ good speakers it would make a huge sound difference in that car! I like this idea too, but frankly all mine with the late style 2 speaker per door set up sound pretty good right now...

Tom in Austin

Great update Hans, look forward to the final deal when you have it all ready ...

Pcplod

I'm also still interested Hans, but as with everything else, price will be the great equalizer. Any ideas on where these are going to come in price-wise?? Sorry if this has already been posted and I just overlooked it.

hans14914

For those who are curious or planning on picking up a set of these drivers. I have confirmed the dimensions of the grills being produced for both front positions. The tweeter grill will be slightly larger than stock at 100mm (for reference, stock is 94.25) and the midbass grill will be slightly smaller at 125mm (stock is 127.25mm). So for all intensive purposes, these will be darn close to stock size, and will keep the help keep with the stock interior look. I could have made them exactly the same as stock, but the tooling would have cost me an extra $1200 to do so. I would have had to pass those costs along to you guys, so i made the executive decision to give up a couple mm here and there and save a couple bucks. If you guys disagree with that decision, I can still make a couple changes and get exact stock dimensions, but would probably collect a deposit from interested parties.

In the same vein, one of the other "compromises" is that the grills will have a stamped indentation for grill badging. I will be working on creating a very demure badge for this location. I will not fix the badge to the grill, and it will be included loose in the kit. Again, I can get plain grills, but would need to toss $1200 at those tools as well to get them stamped plain.

Now to some advantages of the new grill design. It is a 2-piece part, with the plastic and metal being separate. The metal grill can be easily custom powdercoated, painted, or even covered in a colored grill cloth to give a unique look to your interior restoration project. Similarly, the grill mount can be color mathched to your interior without any disassembly or masking. Finally, because of the relatively simple configuration, it will be possible in the future to offer custom machined version of the frame (which will accept the stamped steel mesh insert) out of aluminum, rootwood... etc to make your own "executive optioned" interior.

Any feedback on the above. Are most people ok with the small deviations from stock using the described tooling?

Thanks
Hans

finally!

While I doubt I will be in on this, too many other projects and just redid my stereo system, might suggest if possible at least making the portion of the grill which actually touches the door panel (the plastic ring?) so it matches the OEM size. That way it will cover up the indentation made by the OEM grill being on for all those years.

Make sense?

hans14914

I currently know my price for the custom 4" drivers, the tweeters, and the grills. I do not know my pricing on the crossovers or grill badging. I will be working on this very shortly and starting a pre-order thread.

All of my projects truely are labors of love. I take very little in the way of margins. Because of this, they will be relatively affordable when compared to other competing options.

It will certainly be less than the Focal 100VRS (cheapest street price is $429) but perform significantly better.

Without boxing myself in a corner, the price will be more than $300 but less than $425.

These are not cheap components. I did sample less expensive drivers from other manufacturers. I have had several custom samples built from various houses. These are the drivers you want.

Dont forget, that these are direct screw in with no adapters/spacers... etc. They will save you a $250+ for used door cards if you plan on ever selling your car, and they will have a very high retained value in the 928 community as well. So, improved car resale value + retained component value = good deal for you guys

Thanks
Hans