Christopher Zach

So I decided it was time today to finally take out the factory tweeters and replace them with Hans' beauty-tweeters to go with those 4 inch Hans speakers of win. I'm using an older set of 2 way Quart crossovers for the front speakers, with the new tweeters retaining the original capacitor filters, factory 80 watt amplifier (Blaupunkt, 20w*4) being fed by the line output (DIN) from a 86 Heidelburg head-end (which has 4*20 watt channels itself but I didn't want to rewire the car).

Sounded good, but still a bit ratty so I checked the 2 middle speakers. They were ok, then I checked the rear-rear ones. Let's just say they looked... bad. As in one had cracked cones and one really didn't have cones. My guess is sun damage from the rear windows. I pulled them out, and the rattle is gone.

However should I still have something back there? I know Hans' opinion is that the rear speakers should be deleted on an 87 and up 10 channel system, but how about the earlier 8 channel one? And if so, what? I don't need more tweeter so I would prefer not to have anything with a 2 way, and although I have a spare pare of 4 inch low-midrange drivers they are 2.4 inches deep as opposed to the factory 1.61 inch depth.

Any suggestions on what speakers to put back there to augment the front midrange? There are a lot of discussions about speakers here, but they all seem to be for the 10 channel systems. Also are the middle speakers free-air speakers as well?

bureau13

I replaced the "middle" speakers with Earthquake "mini-subs" and ditched the useless rear speakers. They're too small to act as bass speakers and you don't generally want higher freqs behind you.

In retrospect, Hans offered some matching speakers for the rear seats that I should have bought instead of the Earthquakes, since I ended up putting a proper subwoofer in the hatch, but I wasn't sure about that at the time. If you're not running a proper sub, then something like the Earthquakes is a must, IMO. Note that you have to use something like the stand-offs for the grills with those Earthquakes (Hans made them) otherwise the extension on those speakers will hit the grills.

Christopher Zach

Thanks! Do you have a part number/link to them, and how big are the standoffs?

It's unfortunate: The old Radio Shack Minimus 7 speakers had a 4 inch low driver that sounded quite good and there are poly/metal replacements. But they are a bit too deep to fit in the back spots by about 1/2 an inch, I was thinking of making a mini-box for them.

bureau13

The speakers are here:

Christopher Zach

*Great* I just ordered them, should get here in a week or two. I'll try swapping them in and see how they work. Did you use the same clips as the stock ones, or is that where you had to make standoffs?

Better sound, here I come. Need it if I am going to make it to the Black Hills.

bureau13

If I'm remembering correctly (it's been a while) the standoffs were needed to put more room between the speaker cone and the grill, because these speakers max extension is quite a bit more than you'd normally expect from a 6.5" speaker, or whatever it is.

I don't remember any other specific requirements for mounting, however.

Christopher Zach

Got it. I decided to mount the speakers to the car body instead of the plastic carrier/cover and drilled 4 holes (boo!) With the speakers mounted flush I have close to an inch of clearance, and to be honest I doubt my 4*20 stock amp could drive them that far anyway.

Sound is *really nice*. Only problem is that the system is pretty quiet overall, I think I need a bigger amplifier now that all of my speakers are rated to 200 watts. Is there an upgrade for the factory amp that will fit in the same space (ideally it would use the Blaupunkt speaker plugs but I doubt that would happen so I could buy a bunch of adapter cables).

Thanks for the tip. Much less muddy and more clear base.

bureau13

I THINK someone found an amp that will fit in the passenger side external amp location. I want to say Rockford-Fosgate? But I might be wrong. I briefly looked at something like that, but then I got a chance to grab one of Hans' Sharkwoofers, so I put a five channel amp in that setup.

gazfish

I cut these down to match the contour of the interior panel and worked well as standoffs. Had to get them low enough so the rear seat can still fold down without hitting them.

https://rover.ebay.com/rover/0/0/0?m...2F282989319440

Christopher Zach

Thanks Gaz, will look into that.

Doing a bit more research I found something interesting: When I swapped out the Monterey for the Heidelburg I noticed that the sound was not too great when plugged into the speaker outputs from the Heidelburg. So I built an adapter to drive inut to the amp from the line output (the DIN plug) of the Heidelburg, thinking the Monterey didn't have an internal power amp.

However checking the manuals it looks like it does have a 10w/channel internal amp and that is what goes to the amplifier. Which means the amp may not be built for line level inputs and that could be why it's quiet/distorted. Maybe what I was hearing was the old crummy speakers....

Will pull the radio and side panels today and check this out. Are all amps supposed to take power from the speaker outputs on head units, I would have thought there would be an impedance mismatch or something....

Christopher Zach

Well that didn't work. Heavy distortion, yuck. It's possible the Heidelburg's output amplifier is shot, but I'll just live with line output levels.

Meantime the amplifier that will fit is a Rockford-Fosgate PBR300X4 300 Watt 4 channel amp. I'll pick one up later and install it in the spring.

Christopher Zach

Been thinking about this: The Blaupunkt amplifier has a DIN socket on it along with the wires for the speaker inputs from the radio/head unit. Now, what if the din plug on the amplifier is for a line level input and the normal plugs are for speaker input? In that case I should build an adapter going from the head unit input directly to the DIN socket.

Off to find a DIN plug!

bureau13

I found this: https://jenniskens.livedsl.nl/Techni.../MyTip1092.htm

I'm not 100% sure, but at least based on this, it doesn't seem like there are any line-level connections? Although this implies that the DIN connector is for speaker outs from your head unit to the amp, you're saying your amp has a whole separate set of speaker-level inputs? There do seem to be several variants so I'm not sure what you have is the same as discussed in the link, but it's worth a look.

Christopher Zach

Ok. Retyping this whole thing because my last post blew up. Micro note: Blaupunkt is an insane company.
Let's start at the top: I have a Blaupunkt Heidelburg SQR47 head unit which includes a 4 channel 20 watt amplifier. I'm trying to wire it to the factory BQB80 amplifier so I don't have to rewire the car.

We'll start with the schematics, hopefully the most accurate documentation. Using the manual found at:
https://drive.google.com/file/d/165j...ew?usp=sharing (Page 16 is the key page)
We can see the outputs of the power amplifiers, the pinouts for both the speaker outputs, and the 8 pin DIN output. The speaker outputs are insane. Each speaker line has a round pin connector and a rectangular spade connector. These go to the speakers in the following way:
Left front: pin to amp
Left front: spade to capacitor, then ground.
Right front: pin to amp
Right front: spade to capacitor, then ground.

Left rear: pin to capacitor, then ground.
Left rear: spade to amp

Right rear: spade to amp
Right rear: spade to capacitor, then ground.

If we assume that amplifier output goes to speaker + and cap/ground goes to speaker - then the rear speakers are 180 degrees out of phase with the front. Is this normal/expected?

But that's just the radio speaker outputs. If we look at the 8 pin DIN output we see something different: Each line has one connection to the amplifier output line through a 120 ohm resistor and a capacitor, and there is a common ground to all of them. That ground is frame ground, not through a capacitor. If we assume that we're looking at the radio back (ie: into the female 8 pin socket) the alignment carat is on "top" and the pins are read in a clockwise direction then the pins are 6,1,4,2,5,3,7 with pin 8 being the center pin. They are as follows:
Pin 6: No connection at all
Pin 1: Left rear output
Pin 4: Right rear output
Pin 2: Ground (frame)
Pin 5: Right front output
Pin 3: Left front output
Pin 7: Goes to two transistor gates in front of the amplifier circuits. I think this is a "Mute" function that can be triggered separately.
Pin 8: +12 when unit is turned on, this is for the power antenna, antenna amplifier, or wake up for an external amplifier.

So far, so good. However the inputs to the BQB80 are as follows (same pin nomenclature)
Pin 6: Right Rear input
Pin 1: Right ground input
Pin 4: Right Front input
Pin 2: No connection
Pin 5: Left Front input
Pin 3: Left ground input
Pin 7: Left Rear input
Pin 8: +12 input to turn on unit.

This seems to match the larger spade inputs on the amplifier, but with the following differences:
Input sensitivity of spade (audio) inputs: 300mv to 6v
Input sensitivity of socket inputs: 300mv to 2v
Impedance of spade inputs:47 ohms
Impedance of socket inputs: 10k ohm

The common ground appears to be isolated between the left and right channels. However as we discussed above the Blaupunkt head unit output has a common ground shared between all channels. I haven't calculated the effective impedance from the head unit, but I would guess that with the resistor it's probably a fraction of the speaker output. And if the BQB80 was looking for a 10 watt amp then a 20 watt amp may be overloading it and the DIN output may be too low for the speaker input.

Frankly I am amazed that anything works at all in this world. Maybe the divisions that made Blaupunkt head units and Blaupunkt amplifiers were:
a) Separate divisions
b) They hated each other
c) A lot.

Even more interesting: The BQB80 expects 4 channel inputs to 4 channel outputs. Did they just jumper front to rear on the input side, as there are only two channels coming from the head unit (since it was from a 2 channel radio) and will it be very mad when the inputs reference frame ground as opposed to shared grounds?

More interesting: Remember the stock Blaupunkt units reverse + and - between front and rear, resulting in a rear speaker set that is 180 degrees out of phase with the front. Does the amplifier do this as well, and if so how does it know that the inputs are not already out of phase? If I could find the schematic of the BQB80 I might be able to tell but that seems to be locked behind a dozen pirate paywalls.

The plot thickens....

Interesting. I may try a quick hookup

Hilton

This one? (attached)