From: Baynes, Timothy [tbaynes@kpmg.com] Sent: Tuesday, March 20, 2001 1:12 PM To: 928 Subject: [928] a decent stereo (was Questions for the list) Marc - The amp, in case you haven't found it yet, is under the little box/cover just to the right of the passenger seat. Where your hatch release is. Here's a long answer to your short question about bass. It's difficult to solve all the problems with sound in these cars, for a number of reasons. I've described my approach down below, if you're interested. I think we did a good job of sorting through the problems and made some reasonable tradeoffs. For you Chicagoans, I used Sounds Deluxe on Ogden Rd. I recommend them unconditionally. With regard to the bass, it isn't that good despite all the speakers. It's simple physics - none of them have the surface volume to move enough air. You really need at least 8" of sub, minimum, to get decent bass. I guess you could also do it with a couple of 6.5" midranges in the back seat, with alot of power. That will provide good warmth, but you still won't get down to the 20Hz range. But then, you might not care depending upon your listening preferences. Probably the easiest way to solve the bass problem is to just go buy an amplified subwoofer and stick it in the hatch. You could probably send signal to it with the wires running to those speakers above the rear wheels, since they aren't really doing much for the sound quality anyway. The battery is right there, so you won't have a problem getting power to the sub. You'll have to run a line from the head unit to power it on, though, unless there is a creative way to manage it with the speaker leads. (But I don't think I would.) I started off like you, with a bass problem. But I quickly realized that, to remain faithful to the spirit of the car and satisfy my own rather high expectations, I needed to replace the system the PO had installed. Here's my approach: In most cars it's difficult to find space to mount good components. That's aggravated in the 928 (for most owners) by a desire to leave all interior panels in original condition (no cutting). I also wanted a very stealthy look, with no visual cues to any potential thief. I wanted more than enough power so I could hear good quality sound under any and all driving conditions. And finally, I wanted a head unit that didn't look out of place in the teutonic 928. Preferably one with a display that was simple, clean, and amber. And a rotary knob for the volume since I can never find those stupid buttons. I've spent probably 80 hours over the past year, investigating different approaches to solving these requirements in my '88 shark. Finally, my installer and I decided on the following configuration: - Head unit - Nakamichi CD45z - AM/FM/CD with 3 pre-outs at 4.0 volts and 45 watts x 4 channels. Special order for the amber display, but no additional cost. The high voltage on the pre-outs makes a difference, since you get a much better signal-to-noise ratio. And enough power to run anything. I regret not getting the in-dash CD magazine version already since there isn't a good place to install a changer, but the sound quality is exceptional. - Amplifier - A/D/S 640 (6 channels / 40 clean watts each). I only wanted one amp, due to the space limitations. And the A/D/S isn't too big. I still had to mount it on the floor of the hatch, over the spare tire, though. We fabricated a new spare tire cover out of plywood for better stiffness. The carpet covers it (for stealth), but since the carpet doesn't drape down around the sides of the amp, there is air circulation. Haven't had a problem with heat yet. And I've still got the original board so the car can be reverted to stock. - Speakers - Front: MB Quart Reference Premium Components (PSC 210)- 4" midrange and a 1" tweeter mounted in the original door holes. These speakers are bi-amped (4 channels) from the A/D/S for better control over the sound. We mounted the crossovers for these speakers on the amp panel over the spare tire. It looks like serious equipment when you pull the carpet up. Back seat: MB Quart Reference Coaxials (PKC 116) - 6.5" midrange / 1" tweeter in the original holes. These are powered by the 45 watts coming off the head unit. We used the MB Quart grilles on all speakers. Helpfully, the labels are not permanently affixed and we left them off for greater stealthiness. Subwoofer: Currently MTX Blue Thunder 10" in a QLogic enclosure. Powered by 2 bridged channels off the A/D/S. Sounds good, but looks terrible just sitting there in the hatch. We're going to replace it with either 1 or 2 8" MB Quart subs in a custom enclosure. We won't know if we're getting enough bass in this specific car until we try it, but the goal is to use 1 8" sub if possible. My experience is that the 10" MTX is overkill, by the way. 8" should be enough. The original rear speakers, in the hatch over the tire wells, were simply disconnected. We couldn't find a way to make use of those holes. I guess you could put tweeters or small coaxes in there, but you run into problems with directionality in that frequency range. We felt that putting something in there would cause more problems than it would be worth. We didn't have to do any cutting of the original panels, and no fabrication except for the amp panel to install the system as it is now. And the sound is better than anything I've ever heard outside of a studio. Even including decent home systems. The MB Quart speakers provide an astonishingly authentic sound. I'm sure there are some systems out there that sound better, but I'm very happy with the way this turned out. Tim Baynes '88 5spd South Bend, IN