Kika

YUP, that's the one I was thinking of, but was too lazy to search for. one of the most spectacular interiors I have ever seen.

Spyder_Man

If I'm IDing your amplifier correctly, you have a ST4.1000D with each sub driven separately with 2-channels of the amplifier bridged per sub. Am I correct? So that's 250 W per speaker at 4 ohms and your sub-woofers require 200 W RMS and 400 W peak. You could put more power towards the sub-woofers, but you have at least enough to cover RMS.

Rather than lack of power, your sub-woofers are likely suffering from lack of enclosure volume. I don't know the full specs of these woofers to know their minimum sealed enclosure space requirements. One more question for you, do the sub-woofers have separate chambers or one shared chamber?

Bigger sub-woofers don't always mean bigger sound. They might be able to drive lower frequencies better than smaller diameter subs, but you need to properly enclose the speakers to make them sound their best.

Lastly, since you're local I'd love to see/hear that setup in person. I'd also love to take some measurements for my own possible custom RSD sub-woofer enclosure.

Vorsicht

Actually, it is the ST1.700D Mono Amp (250 watts RMS at 4 ohms) configured in parallel. This is how they were wired when i got them so i went with it. That gives me 125 rms per sub, right? So, probably not enuf. Each of the subs is rated at 200w Thermal Power Handling (whatever that means).

Regarding the enclosure: Each sub sits in its own enclosure which takes up all of the space underneath. Based on the original specs for these speakers I am assuming roughly .7 cu ft. per as the enclosure was made for these subs. The boxes are upside down trapezoid in shape.

I'd be happy to meet up (I'm in Oakland) or anywhere in bay area (any excuse for a drive). In fact, you are welcome to borrow the enclosure to make a copy if you want - just have to return in a reasonable timeframe.

Spyder_Man

.7 cu ft per subwoofer might be enough. It depends on the subwoofer specifications. Also since you have two 4 ohm speakers wired in parallel the amp will be seeing 2 ohms impedance and the ST1.700D will provide 350 W at 2 ohms. So you're getting 175 W per speaker wired to that amp in parallel. Replacing it with the ST4.1000D or another more powerful amp that has a similar footprint to the amp you are using now might help your setup because your current amp is definitely underpowered for those subs. Phoenix Gold is a very well received company in the mobile audio world, so unless the cones are damaged on the speakers I doubt that's your issue.

I used to live in Oakland. I'm up in Marin. Perhaps once stormageddon has come and gone (and possibly the Christmas frenzy as well) we can coordinate a Bay Area RL meet-up. Perhaps a New Year's Day drive?

1990-964

A Bay Area gathering would be great. I'm working on subs and RSD also. Hope to finish it by years end. Would enjoy comparing notes

mpruden

This is now completely OT, but I'll be in the Bay Area quite a bit in January and would like to crash the party if you all are getting together.

Subwoofer... there, it's back on topic.

Spyder_Man

I've started a new thread regarding a possible meet-up. Now back to subwoofers...I still like the idea of having capable woofers/subwoofers in the door as part of a 3-way from stage best.

Fitting in enough amplification for a 3-way and selecting speaker components that will fit the OEM locations is the challenge therein. If one doesn't care about OEM appearances then it wouldn't be so hard to do, but then you might has well have a subwoofer RSD installed.

Vorsicht

I believe since they are DVC the amp is seeing 4 ohms (as per below). In any case I have to find a new amp with more power. The problem is getting one to fit under driver seat. I am saving space under passenger seat for a new amp to power new front speakers (probably a pair of Polk DB6501 which are each 100w RMS).

Perhaps my best bet would be to get a single amp to power the subs and the fronts and let head unit do fill for the rears (or just remove rears). Any suggestions on amps?

Spyder_Man

I didn't catch that those subs are DVC. You're correct about the overall impedance then. I've been looking at the small Phantom amps made by Precision Power (or PPI). They seem well received and are relatively cheap. I'm debating whether I could manage to fit two of them in my 993 (one under each seat). It would be snug, but it would provide me with plenty of power option.

If you're looking at a two-way front + subs, then possibly their 5-channel Phantom amp? Unfortunately, the all-in-one amps start getting rather long and hard to fit under a seat. Splitting the setup with two amps might be easier. Others have used Alpine, Rockford Fosgate or Hertz amps with success. PPI just seems to pack the biggest/cleanest punch in the smallest package (other than some really expensive European amplifiers like the Mosconi D2).

Good luck!

Kika

I had a 4 channel Precision Power amp in my SC, great amp. I used to really like Fosgate, but they are mass produced now, and made over seas. I am a big fan of hand built amps made in the USA. I have Lunar 2125 that rocks. I don't know if they are still in business. The only other manufacturer I recall as being US made was Tru Technologies. Even with Audison, their lower lines are made in China, only their high end line is made in Italy.

Orion was a big name in the day (80s) but I haven't heard much about them lately.

I really like the sound of Hertz speakers, don't know much about their amps though.

Nice thing about Alpine, JL Audio Rockford, is that you can get replacements easily.

nathan1

I literally have tons of audio equipment I have pulled out of these cars over the years including two different subwoofer enclosures built by Sound Audio Innovations. I have probably 20 late model head units, amps, etc. For any good, contributing member I would probably give any of it away if someone pays shipping. I used to be into audio but now all my cars either have all OE stuff or blank out plates. I'm starting to feel old...

M. Schneider

I'm in trouble .... just looked over the Finishline Interiors 911 rear speaker (LF) crafted in the right/left side panels. ...I'm in trouble, slippery slope alert ....
The rear oppositional positioned LF woofers. Out of phase, maybe not? enclosure cubic ft.? Possible reflex loaded, maybe not. Linearity? The clever perforations look good, acoustically speaking its a challenge; SPL?? .. LF woofers boundary located aren't typically ideal .... add oppositional to each other?
The stealth aspect and leather work is beautiful artistry. Luv the stealth HiFi install. .

Here's a link to the artistry at Finishline Interiors
www.finishlineinteriors.com/index.php

pp000830

I ended up replacing the door drivers with ones that have a listed frequency response down to 35hz and put a SOUNDSTREAM BX10X low frequency digital signal processor (DSP) in-line to the front speaker signal wires from the head to the 75w/ch power amp. It cost $60 and re-equalizes the sound and synthesizes additional signal in the <100HZ range. The sound is much improved, clear and precise and smooth, in my opinion, it eliminated the need for a subwoofer. The drawback is it is easier to overdrive the door speakers but this has turned out to not be a significant issue in daily use. Minimally invasive and seems to do the trick. If you are looking for bone ratting bass with your Funk this is not your solution.
Andy

M. Schneider

Hey Andy -
Good to hear of your success regarding the operation of the psycho-acoustic bass frequency enhancer. These are kwel kits.

I'm done with the 993 project in so far as the active audio goes. The stealth, finished product exhibits wide dynamic's, good to great wide sound stage, killer imaging (out front, dashboard height) and wide band linearity. Very pleasing to listen, be it talk radio or +110db .. In-A-Gadda-Da-Vida ..... Hot Rod Lincoln, Peer Gynt, etc.

All the playing around of the recent past has paid off. The starting point was to understand & validate what Porsche/Nokia created and to discover what enhancements can be made given today's 12V automotive HiFi gear, namely herculean DSP filtering. Initial measurements were surprising as this indicated a less than minor polar pattern interaction btw (800hz through 5Khz) when utilizing the left/right 2.5inch speaker enclosure positions. Try taking "on axis" a string to physically visualize the intersection of these two positions and notice the relationship to the front seating positions, dashboard, etc.

The HiFi enclosures mid-woofer position show's a forward aiming bias, about 15* aimed into the footwells - largely to exploit the natural transfer function (gain) of the interior boundaries. There is plenty of cabin gain, to much actually. IIRC its less than 23" to the center console where the polar pattern of each right/left mid-woofer collide.
The mid-woofer position is re-used with a 6" Seas woofer but without the "transfer function" so much, the mid-woofer is crossed at 80Hz with a 18db slope.

The addition of an active folded horn enclosure type subwoofer rounds out the HiFi systems layout. A Japan domestic market Pioneer model TS-WX77a was bought on a flier a few years ago,,, given that these gismo's aren't usually all that trick...I never got around to explore its capability. The folded horn aspect caught my interest as this just might load & decay LF in lockstep with the boundaries of the interior.
The folded horn performance is in SPADES. Strong linearity, the sub-F-K' ing rock n rolls, never boomy .... high efficiency without any localization artifacts. Really lucked out. With the rear back seats in the down position, the unit fits snuggly across the area from side to side. The enclosure exits on the left, 3 or 4 inches from the side panel. When in position your eye looks past the flat 2.5-inch enclosure height. The plug n play connectors make for easy 1-minute removal. We got lucky, the device acoustically works very well.

All of this is to say ... the HiFi enhancement isn't finished - a goal was to achieve non-invasive enhancements with 100% stealth aesthetic .... so I'm not quite there.

A 993 forum search shows a couple of TS-WX77a pictures I'd post ... way back when.
Fast forward 2015 and there is a new superseded model number TS-WX710a ...so says Google search.

Good luck with your projects.

pp000830

Your post is impressive and you have clearly given the audio a lot more thought than I have. I would say the key issue I have not addressed is frequency phase related matters that can make audio sound harsh. I am sure if one is willing to buy a engineering quality DSP with the microphone feedback loop phase issues could be addressed by brute force electronics.

From my perspective an investment to resolve this issue is well beyond where I am willing to go so I guess what I have now is as far as I am going down the slippery slope.

Having the DSP in my car for a few weeks now I would recommend this $60 DSP solution I list above for those who have gone to the trouble to upgrade their power amp under the seat as for a small incremental cost it adds to the sound quality. The unit is less than an inch tall. In my install I cut a rectangle out of the passenger side rear floor carpet foam and placed the unit with a little foam pad around it. When I place the stock carpet over it it disappears under the carpet and is right next to the power amp under the passenger seat for an easy interface. The remote control for it is on a phone style 6 conductor flat cable. It comes with a very long one so I purchase a one footer on ebay. I set the remote level, tucked it under the seat and do not bother with it.



Andy :-)