[BobSaabit]

Gents: Need some advice on a stereo upgrade. Sorry for the long post, but I figured I should give you all the info.

Found at the u-pull (all circa 2005ish, but looks to be in good order):

• Doors: Polk DB5250 5.25" packaged with dome tweeters Polk Audio db5250 5-1/4" component speaker system Certified for marine use at Crutchfield
• Rears: Polk DB6750 6.75" (holes match stock Saab spacing) Polk Audio db6750 6-3/4" component speaker system at Crutchfield but they have the dome tweeters built in, more like these: https://www.crutchfield.com/S-iaI67XWERQq/p_107DB651/Polk-Audio-db651.html
• Dash: the dome tweeters from the above DB5250 package creatively mounted via stock Saab speaker frames.
• Amp: 4-channel x 110 Infinity 7450/7451 Infinity Reference 7540a 111W x 4 car amplifier at Crutchfield (Amp panel view: Infinity Reference 7540a 111W x 4 car amplifier at Crutchfield )

• No Polk supplied crossovers in evidence.
• Rears were set up with soldered on 27 uF crossover capacitors that I think feed the built in domes (need to test). Might just be filters(?). but the dome wires didn't appear to be cut free.
• The door speakers were wired direct, no crossovers/filters evident.
• I think he had the rears feeding the dash speakers but have to go back and study that. He was using non-stock feeds at the dash.
• Amp had RCA input feeds, so there must be some LOC's in the lines somewhere. Have to look.

My listening:

I definitely don't need all this power. I don't plan to run a sub. I don't listen to hip-hip, rap, etc so bass is not my thing. But, you really can't listen to the stock system very well on the road in a 'vert with the top down... volume has to be way up and the sound quality suffers. I'm guessing that running a large amp at low watts into good speakers would get me much better quality.

Questions:
- Power: The amp pulls up to 54A fused 30A X 2. So, I'd need to run directly off the battery. Is this a serious load on the alternator or battery? As in battery or charging system damaging? I'd guess only be using something like 15 -20 watts a channel at most I'm guessing. So I don't expect to be pulling a lot of current. Advise me.

- Hookup: I'd like to run with a similar to stock configuration where the dash is high freq (no choice, domes), the doors are bass (and maybe some mid?), and the rears are either bass (stock limit?) or full range. I'd like to be able to use the fader per stock. Is it doable? The amp has some switchable and adjustable HP/LP/Flat filtering, but I'm guessing that my issue is more of trying to find full range feed for the rear, not filtering it out. Has anyone modded the stock radio to remove the filtering and get full signal to the rears?

Lastly... is it practical to tap into the stock wiring? I don't mean the physical part, but can I use the DIN feed to the AS3 amp and run that to the front (door) channel? Or should I pull the output from the AS3 amp and send that back since that's the signal level I will get from the rears coming out of the stock radio? Maybe feed pre-AS3 front input (unfiltered) with the amp level input set high and the rear with the input level set low? But, what happens with the dash domes then? Give me some direction.

Thanks,

 

[EdT]

I don't know all the answers. I can give some hints.

You need to test all the speakers for proper function. They won't sound real good when sitting in the open air, but at least you can tell if the the driver(s) are okay.

The simplest first step would be to install the aftermarket speakers in place of the stock speakers. Some of those seem pretty efficient, others not so much. It should all work, though, even if it doesn't play that loudly, or you have to turn the fader quite a bit in one direction or another.

Now, if you need more power, you can think about wiring in an amp.

In my opinion, that Infinity is way overkill for what you have and want. There are plenty of much smaller four-channel amps with more modest output that will fit in more nooks in the car.

The brute force method is to use the front and back high-level inputs. The two problems there is that you are still dependent on the door amp working, and the wiring for the doors is not in a convenient location with the dash/rear wires.

While I have wired an amp into an NG900, that was just for the back speakers and the car didn't have door speakers at all.

I would think about finding the wiring to the door speakers, and bringing it back to your new four-channel amp, and running it off the front channel, in parallel with the dash speakers. The amp should be able to handle it. Then run the rear speakers off the rear channel. You should be able to use the high level outputs of the head unit for the front and rear channels, thus ignoring the door amp.

 

[jvanabra]

I am pretty sure the stock configuration is full range to the dash and rear speakers, and even full range to the door speakers - but the factory amp has a crossover which blocks high frequencies. The head unit itself is pretty braindead.

The question here is whether you plan to use the factory head unit to drive this new equipment.

 

[BobSaabit]

Yes, using the factory head unit. So maybe I should sell this to someone who needs ridiculous power and just get a small, reasonable used amp with the funds? TBH, this wasn't really on the project list, but I sort of fell into it and it seemed a shame to leave those speakers behind at the yard.

I did notice the senitivity on the 5.25 doors is 89db (fair) and the rears 92db (good). But that might work since you sit at the door speakers. I've also been told there's an adjustment on the door amp for output but I've never hunted it down. With the amount of power in this amp, it wouldn't be an issue as long as I could balance them with the fader front (door) and rear.

I thought the rears were full range too, but if you look in the WIS Electrical > Audio > Meter -/+ Icon > Main Unit or Ext Amp (credit to Mimmi for the reference) both the rears and doors are "bass". No frequency range is given.

 

[jvanabra]

Possibly, but I wouldn't read too much into that. I suspect the description there is a function of speaker limitations rather than audio processing at the head unit. Just a guess though.

If there is some sort of internal crossover, it would be a WAG choosing good aftermarket speakers since you don't know crossover values.

If you do need to keep the stock stereo, you're going to have to some experimentation to see the best way to wire this up. My advice would be spend the $100/$150 on an aftermarket stereo and do it right.

 

[Jeremy R.]

I don't think there's any sort of internal crossover in the factory headunit. I've run full range speakers in the rear, and you can hear high frequencies coming out of the tweeters. It's also true that the line-level outputs in the DIN jack on the headunit are full range. I put together a system years ago using the factory headunit that used all four line-level outputs from the DIN jack, connected to a crossover that derived a non-fading subwoofer from those. I ran a four-channel external amp for the front and rear speakers, and a mono amp for a 10" subwoofer in the hatch. It sounded great, but having a cassette deck in the dashboard with no built-in Bluetooth or iPod control was too much of a limitation for me in the end. Now that my NG900 is no longer a daily driver, I've ditched all of the fancy audio components I had in the car. I now have a cheap Pioneer double-DIN media receiver directly powering the dashboard and rear speakers, and the Pioneer's subwoofer output is hooked up to the factory door speaker amp and a pair of factory door speakers. The fronts are JBLs, and the rears are some cheap-a** MB Quart speakers that will go as soon as I decide to spend the money on matching JBL speakers for the rear.

 

[jvanabra]

Short of a new head unit, that seems like the right approach.... build an adapter to connect the DIN line out on the factory head to the 4xRCA input of an amp, and drive the door and rear speakers, then power the dash speakers with the head unit. An alternative approach would be build or buy a crossover, then power the door/dash on one channel and the rear on another. You would have to pay attention to speaker impedances going this route or risk damaging the amp. It looks like it is 2ohm stable so you should have flexibility there.

The 2x15w rating of the head unit is a limitation for any sort of clear audio with the top down... but that 4x110 is gross overkill. might be a good excuse to split channels.

I would bench test those speakers for a while before bolting them in. 15 years is a long run - I would want to be sure they're gonna stay together before putting them in.

 

[BobSaabit]

...connect the DIN line out on the factory head to the 4xRCA input of an amp, and drive the door and rear speakers, then power the dash speakers with the head unit. An alternative approach would be build or buy a crossover, then power the door/dash on one channel and the rear on another.

My thought with option 1 is that the dash speakers are then underpowered at any given setting since the doors/rears are more heavily amplified. The AS3 amp is not going to be boosting the dash speakers... "or is it?" Maybe I could keep the AS3 amp and just re-route to run the dash, although I have heard that it actually has a filter in it that limits the frequencies sent to the doors.

I actually do have a spare pair of crossovers... they were for another used bi-speaker project that was aborted.

The 2x15w rating of the head unit is a limitation for any sort of clear audio with the top down... but that 4x110 is gross overkill. might be a good excuse to split channels.

Agreed. My initial thought was from my guitar amp background... big amps at low settings are ultra clean. What's "splitting channels" ?.

I would bench test those speakers for a while before bolting them in. 15 years is a long run - I would want to be sure they're gonna stay together before putting them in.

Yeah, I will give them a check. But, they are better (synthetic) materials than stock. No paper, no rubber. They sure look fresh.

I don't think there's any sort of internal crossover in the factory headunit. I've run full range speakers in the rear, and you can hear high frequencies coming out of the tweeters.

Interesting. Anyone got a scope? :- )

It's also true that the line-level outputs in the DIN jack on the headunit are full range. I put together a system years ago using the factory headunit that used all four line-level outputs from the DIN jack...

Good to confirm.

Another question: What's the 27 uF capacitor doing? I'm familiar with the tone limit (filter) idea of a capacitor/resistor combo. What would a capacitor by itself do in these conditions? Does it work with the coil of the speaker to form a filter to the tweeter? Or is it doing something else?

 

[jvanabra]

My thought with option 1 is that the dash speakers are then underpowered at any given setting since the doors/rears are more heavily amplified. The AS3 amp is not going to be boosting the dash speakers... "or is it?" Maybe I could keep the AS3 amp and just re-route to run the dash, although I have heard that it actually has a filter in it that limits the frequencies sent to the doors.

The relationship between watts and "loudness" is complicated - the difference between a 15w amp and a 100w amp doesn't really create the additional loudness the numbers might suggest. Running the big speakers from the amp and the small speakers from the head unit shouldn't be a problem other than possible distortion at high volume from the underpowered speakers.

Agreed. My initial thought was from my guitar amp background... big amps at low settings are ultra clean. What's "splitting channels" ?

You could power both the dash and door speakers from the same front channel and the rear speaker from the rear channel. You'd need to be sure the impedance presented to the amp is within its range, though. You might also need to futz with the amp gain or fader control to balance things out.

Another question: What's the 27 uF capacitor doing? I'm familiar with the tone limit (filter) idea of a capacitor/resistor combo. What would a capacitor by itself do in these conditions? Does it work with the coil of the speaker to form a filter to the tweeter? Or is it doing something else?

The cap is the crossover (filter). It's the simplest/cheapest form.

 

[BobSaabit]

New developments:
- I think I found a quality used amp that does 4 channel w/40w per. Only draws 15A, so that's probably more what I need.

- My SRS issue (other thread) may be resolved w/o changing the driver's belt, in which case I may postpone my speaker upgrade, which postpone's my combined amp upgrade

- The stock rear speakers for the 'vert have a built in filter/crossover. Capacitor, Coil, Resistor... photo tomorrow. If I get ambitious I'll try to run the values through the crossover formula to get a frequency.

But, it lends weight to the theory that all the frequencies are there in the rear wires, they are just not output by the speakers. It's odd that the 3D/5D don't have the same filters on the rear speakers but maybe Saab figured that the rear seat passengers needed some mid/treble in those cars. I seem to recall that they do have paper tweeter cones in the originals... (anyone remember?) but I might be thinking of another Saab model.

I know the convertible door speakers, which are supposed to be bass, have no built in crossover/filter. I've replaced them a few times. But, I think someone here said the amp filters the output to those. (Jeremy, was it you?).

 

[jvanabra]

The external amp has a built in filter so that the door speakers are only LFE.

Probably the reason the factory speakers have built in filters is because they are crap and the stock stereo is crap, and the filters help prevent horrible distortion from the crap components and/or then failing from horrible distortion.

 

[BobSaabit]

The external amp has a built in filter so that the door speakers are only LFE.

Probably the reason the factory speakers have built in filters is because they are crap and the stock stereo is crap, and the filters help prevent horrible distortion from the crap components and/or then failing from horrible distortion.

Wait, what are you saying about the stereo? Honestly, there are much worse systems. Clarion was fairly good at stereo. And comparing to modern systems isn't really valid. But, yeah, it could sound better.

 

[jvanabra]

IMO The 9-3 system is on par with the factory c900 Clarion system - it was quite good for 1988, but IMO just doesn't have a place in a "nice car" in 2000. A contemporary Ford Focus had more punch! It really doesn't matter at this point - all 20 year old stereos are old and busted anyway… my point was only that I'm sure there are crossovers on all the speakers because the combination of speaker and amp would have sounded terrible and not lasted long without them.

 

[Jeremy R.]

The stock stereo in my '97 900, even with the door speakers and the fancier two-way dashboard speakers couldn't even begin to compare to the mid-range stereo in my mom's 1997 Pontiac Grand Prix. It was comparable to the stereo in my dad's 1988 Honda Accord, as far as sound quality goes. The Saab's head unit was so severely underpowered and the speakers were such low quality (except for the door speakers) that replacing them with almost anything from the aftermarket was a noticeable improvement. If you want the stock look, at the very least I'd add an external amp for the rear speakers and replace the front and rear speakers. The door speakers could use a slightly more powerful amp, too. I can hear the bass at a stoplight, but the noise of the engine drowns all of the bass out at almost any speed.

One thing I've considered is splicing in the amplifier from a 9-5's Harmon/Kardon stereo and installing the left and right dashboard, front door speakers, and rear parcel shelf speakers in my NG900. I'm more than impressed than how the stereo sounds in my wife's 2001 9-5 sedan for an older stock stereo. The 9-5's amp is about the same size as the door speaker amp in a NG900 or 9-3, despite powering 9 speakers in a sedan, and 8 in a wagon.

 

[BobSaabit]

Jeremy: I had the same thought... perhaps use a 9-5 amp. If you're interested, I have a set of 6x9 HK's that I will part with for a low price. I might still have the fronts... but perhaps only one. I got the 6x9's for a 5D upgrade but then, as usual, ran into some aftermarket speakers that were way better the next week at the U-pull. So, these never got used.

I had difficulty trying to fit the 9-5 HK's into the doors in my 'vert. They are the same diameter but the baskets are different. As I recall, the door panels were going to end up pushed out 1/4" by the mounts. I ended up with aftermarket speakers that I had handy... still having to cut the lip of the baskets down, but the 9-5's weren't going to make it even with that done. It's been a while, so I won't say it can't be done, but I don't think it was looking easy.

I'll study that 9-5 amp and wiring a little bit before committing to something aftermarket.

 

[Jeremy R.]

Let me think about the 6"x9" speakers...

I noticed the same thing about the door speakers, but I think that the 9-5's Harmon/Kardon speakers will fit in NG900/9-3 baskets. Saab now sells the Pioneer door speakers from the 9-5's base (non-H/K) stereo as replacements for the NG900 and 9-3's door speakers, so I bought one new, and found another one in great shape at Pick-n-Pull. Unfortunately they come with the same baskets as the H/K speakers, so like you noticed, they pushed the door panel out. I found an older NG900 with blown door speakers and took the baskets out of that one, since my originals were long gone, and then put the new Pioneer speakers into them. Everything fits perfectly that way. I have a pair of H/K 9-5 door speakers at home, so I'll try putting those in the doors when it gets a little warmer and less rainy outside.

 

[BobSaabit]

Hmmm... interesting. As you might guess, I definitely tried the HK's in the stock 9-3 door setup but it didn't work.

I've recalled more of the details... and I think I understand now. The 9-5 HK speakers have a 1/4" lip on top (speaker meta; frame and the basket). Even in the 9-3 basket it still sticks out too much and pushes out the door panel. The stock 9-3 speakers have a lower profile on top. I was able to use my aftermarket speakers with them... although I seem to recall a basket mod of some sort.

The later Pioneer speakers you used and that Saab is selling now must be made to the lower profile. So, it works in either car.

 

[jmkcc]

And down the rabbit hole you go... You have to love audio in a vert. Here's my two cents. You do need power so go with a good amp (I've always assumed oversize is better then undersize but if a sound engineer can opine it;d be great). Good speakers need to be driven with adequate power to deliver their best sound.

I've experimented with compact amps (Alpine, Clarion, Kenwood) and I find there is a noticeable difference between them and full size amps. I recently swapped from Clarion XC1410 compact amp that can fit where the OEM amp sits to an Alpine MRV-F4300 which fits OK under the passenger seat. Huge difference particularly with base. It's driving two sets of JBL GX600C component speakers. I mounted front tweeters in the oem dash and the rear tweeters semi flush in the windscreen holder holes in back panel.

I'd also recommend a new head unit, but that's an extra PIA given the dash size and trying to make it look like it belongs in the car. I was experimenting with marine receivers and the very limited number of blue-tooth preamps like the Infinity INV-BC4. I actually installed the Infinity but it died before I could tune the amp to it. There are also new bluetooth amps but they look like they still need to develop a bit before I'll try one out. It's too bad the Infinity died before I could really test it because the idea of a quality sound discrete bluetooth preamp would open up options to people who want to leave the OEM receiver in the dash so it looks nice. I eventually gave up and installed a Jensen double din with navigation because I could not find an acceptable discrete solution that worked and looked good.

Anyways, if you stay with the OEM radio, I wonder of you could run new speaker wires from the amp and use the original speaker supply wires as high level inputs to the amp. That's avoid splcing or creating a new cable and it's not that difficult to run new wires to the fronts, rear and to the door harness connection near the oem amp.

I love my current setup. It drives loud and crystal clear whether the top is up (with all the rattles and creaks I will fix some day) or down. I like my music loud and I hate distortion. You don;t have to break the bank but you do need a decent source, a good amp and good speakers. It might even be worthwhile running wires/cables and placing the big amp you found in the boot.

BTW, I powered my amp with 10ga wire direct from the battery junction box through the firewall down the center to the passenger seat with a big old breaker fuse in the engine compartment. Even with a higher draw amp you'll probably be fine with 8-10ga as you will probably rarely use significant power for an length of time.

 

[jvanabra]

That is one advantage of using the compact Class D amps.... they are 70-80% efficient vs. the analog Class AB amps which might be 50% efficient. You get a lot more sound from less amps, at the potential expense of dynamic range. Older Class D amps (that Clarion could be one of them) had very narrow ranges - some people suggest they are really only good for bass. Newer Class D amps are more capable, but it's still important to see what that range is before selecting one for a general-use application.

 

[BobSaabit]

Hmmm... much food for thought here. I will puzzle my puzzler. It would be very convenient if I could fit something into the space where the current external amp is and just wire it all up under the dash. But, I know space is very limited there. Under the passenger seat would be alternative.