P80 Speaker test box - Guidance required!

[scot850]

The V/S70 speakers are the same for the dash, the front doors and the rear doors. The differences are the rear speakers. S70's have 2 larger speakers on the rear parcel shelf similar to the door speakers, where the V70/850 wagons ahd 2 small speakers that mount to the rear tailgate surround pillar.

C70 speakers are also the same for the dash, but different for the doors (2 door) and as I found some have just 2 speakers build into the rear side panels (I guess similar in style to the V70 rear speakers) but can also get 2 sub-woofer speakers behind the rear seats. The C70 coupe has the speakers in one the back shelf like the S70. So a fair amount of variation.

I plan to design the system for the wagon but add in the capability of swapping the rears out for sedan speakers. Haven't figured out what to so far for the C70 yet, especially as I am missing one of the small 'tweeter' speakers from the rear side panel.

Hey it is a fun project for once (mostly ). I will find a way to change the speakers out as/when I need to test any. Once I have tested my current 'spares', and possibly those a friend has, then I will probably leave the speaker box as is and just use it for all the head units I have as well as the amps and the cable harness for those.

Do I need to do this, no. Can I use my R for this. NO. Too much brittle old plastics, that is why I wanted to go this route. With the wood I had it all taking up space anyway from other house projects, loads of screws, glue, staples, pins kicking around so the only real cost was the power supply which I use for other stuff to and to test other auto parts, and some wiring which I got on clearance and lastly the banana plugs and sockets. Heck, I could use it for music entertainment in the garage!!

At least today I got the main wood box frame cut and assembled. I need to buy one piece of 2" x 3" as I miscalculated how much I had. I can then cut the sides and top and bottom covers to length and assemble the rest. I will upload pictures when I am finished.

Neil.

[scot850]

How does that saying do? " Measure twice, cut once".

I measured and pondered many times before starting. I am trying to use up stuff left from the house reno and reduce the amount of stuff lying around in the garage. That means there are certain constraints like the size of the top and bottom covers. These were 2 leftover pieces of plywood with a fixed width but some flex in the length. Spent a while figuring out how to try to make this framework as light but sturdy as possible. I built the frame 6" from top side to bottom. These again are fixed widths and the minimum I can work with due to the rear door speakers.

I don't own a table saw as I seldom use one and usually a mate has one I can borrow or use. In this case my buddy was going on vacation the next day so he kindly cut the wood to the sizes I asked.

All was good until I made the framework, glued and screwed it together. It was only this morning this idiot realized that the frame was made the same size as the top and bottom panels. This did not take into account the width of the side panels...........DOH!

So modifications needed an fortunately I have another larger piece of plywood I can cut down for purpose. I will now make the lid possibly a slide in item which will allow me to use one of the original panels.

It has been frustrating as I also found that one of the sides of the frame the 2" x 3" had a twist in it I had not noticed while being in storage. Had to unpick one corner to straighten the corner post.

At least the frame in now complete and the 4 sides are fitted. Next need to cut the bottom panel. Had originally thought about making it removable, but it is not really needed to be as the speaker panel will be hinged.

Ah, the joys!

Neil.

[scot850]

Not much progress due to a string of unplanned household equipment failures needing attention.

I have though got the side panels cut and fitted and the bottom panel cut but waiting fitting. I am still not sure if I want to fit it permanently or make it removable. I'm thinking that I will make it fixed, as the speaker mounting panel is hinged. Still trying to decide if I want to make the speaker mounting panel split in half (top and bottom) with only front speakers on upper half and rears on lower. Again it just makes the panel easier to work with it will require a few more screws but I have the hinge which is long enough for at least 2 panels.

Today I bought some aluminum angle which I will use to protect the bottom and side edges, as well as a 1" x 2" angle which I plan to use to make a slot so the top cover can just be slid in and out for storage and use.

Hopefully I can get back to the assembly on Thursday. I have cut the speaker mounting panel down so it now fits, but need to make the decision on the 1 whole sheet or 2 halves.

Neil.

[BlackBart]

When I was a little kid and loved music, I decided I needed Surround Sound or Quad sound in my room. I found some junky little transistor radio speakers and wired four of them in parallel back to the little mono radio I had. .... Hooo-ee, that was some quality!

[scot850]

I don't expect this will be much better as the speakers are too close together. But then who knows??

Progress is being made and hope to have the box build mostly done tomorrow. Typical it is waaay overbuilt!

I'm planning to make a slide top cover for the box and now have the aluminum angle I needed. Unfortunately, I really wanted 1/16" but largest locally is 1"x1" which is not wide enough. So I ended up with 1/8" which is way overkill but all that was easily available.

Still tormenting myself on whether to split the speaker panel into 2 with fronts on on half and rears on the other. Might make it easier to work on when swapping speakers over. Only issue is I will need a piece of 2" x 3" wood to mount the extra hinge on and I would have to go buy a 8' length for the 20" I need. I'll decide tomorrow before the snow comes in!

Neil.

[scot850]

Hopefully this will post without kicking me out again. Sorry, but spent hours trying to fix my account with Matthew but for some reason it keeps junking my posts and kicking me out.

A quick update, as no point trying to post pictures as last time the long update was deleted.

So box build and nearly finished. Just some 'trinkets' to add. Rear speaker mounts done, and fronts are 50% there. Just have the small dash ones to do. Hardest part is none of the speaker mount legs are the same length! Then the wiring. That should not be too bad as I have everything for that to hand. Maybe a day of soldering and another half day in the wiring connections.

Neil.

[scot850]

Thankfully Matthew has fixed the logging out issue for now and hopefully going forward for which I am appreciative for. He took a fair amount of time and suddenly it started working again last night! Yay!!

So I have mostly finished the 'box'. I still want to tweak it a bit (for aesthetics only but also to protect the edges), but that can wait. I want to get this operational as soon as possible as I need to clear all the head units off my workbench as hopefully spring is coming fairly soon which means moving the 'R' from storage and repairing the dash mounts ready for the summer/fall season this year.

I do want to add some wheel casters to help move the unit around to same my old body from having to lift it!

I have just started on planning the wiring. This is (even for me, a total electrical luddite!! ) fairly straight forward but will take some time as there are 2 wires with 2 ends for each of the 8 speakers. This means a lot of end soldering and wire joins to make for the connectors for each speaker. Not difficult, but just time consuming!

I do have a question for any of you audiophiles out there. I think I am correct in my memory in that, each wire to every speaker should be the same length. Is this correct? So if the longest wire needs to be say 4 feet, should all wires to each speaker be 4 feet in length for a balanced performance? Or is it the wire lengths to the same speaker position (left and right) have to be the same and the lengths to each pair does not matter. I have googled it but it depends if you look at audiophile websites or technical websites.

The rear 2 Left speakers are joined together so I will make those also the same overall length. Same for the Right rear speakers.

I will probably make the wires all the same length as that should cover the bases!

Here are some pictures:

Support frame

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This is the starting point. Building the main support frame.

Donated hinges cut to length

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My buddy donated a 6ft piano hinge to the project. I decided to make to 'flap' panels for the front and rear speakers to make working on them easier if I have to swap them out for testing.

Main box mostly complete

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Box frame mostly completed with flaps panels for speaker mounts being added.

Naturally none of the speakers is made to make it easy for this purpose. All the speakers have their own challenges to flat mounting depending on where in the car they are. I did not want to cut them up to make it easier as they may be needed one day!

These are 2 (not particularly well cut out templates) for the rear speakers giving some idea of the challenge to mount them to a flat panel.

2 templates for rear speakers

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Final picture is of the mostly completed box:

Box mostly completed

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This is before the holes and mounts for the speakers were made. I will add some more pictures later. I have now mounted the speakers and removed them again for wiring the box. The box has a sliding cover for storage and beefy aluminum angle irons for protecting most of the top and bottom (and yes there is only one of the speaker flaps mounted in the picture!!)

Neil.

[scot850]

Well got the system mostly wired up. Still have a few temporary connections to finalize, but otherwise it works. I connected the speakers to a SC-816 head unit with a CD disc in it and I was pleasantly surprised how good it sounds. All speakers were working.

Last think to do is to wire in a connection for the antenna. Sure a manual antenna would be easier, but where is the fun in that??

If I knew how to post a video I would add one from my phone of it working yesterday.

Neil.

[scot850]

Well, now the system is up and running! Not to say I won't continue to tweak and improve it over time if I find shortcomings, but for now I can fully test a radio/head unit including the signal via an antenna, test the CD changer operation, and finally the cassette portion (I think?!).

I have one of those fake cassettes you put into the cassette slot to play ipods and the likes. Question, does it actually test the operation of the whole cassette player including the drive belt, or does it just use the contact head in static position? I need to see if I still have a cassette I can try, but none have been used in about 20-25 years so who knows if they are still good to use?

Here are some pictures:

PXL_20230330_223950823.mp4

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Audio test system operational

Hopefully this sound bite will work!

I am getting close to the maximum for a download so may have to upload this and then add pictures.

This is the speaker system box completed

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Storage cover in place

PXL_20230328_220548901.jpg (461.15 KiB) Viewed 80 times

This has been an interesting challenge and although frustrating at times, I can now at least test all the head units on my workbench and clear them out of the way to get workspace again!

Neil.

[scot850]

The sound bite does not sound as good as I had hoped, and the video portion has not downloaded for some reason?

Neil.