Topic: 350 SE rear speakers

[Papalangi]

I was not bright enough to take pictures of the install in the '76 280C but I'll try to explain what I did.

In the front, I made new kick panels that replaced the existing cardboard and carpet panels.  By layering 3 pieces of 3/4" MDF, I got enough depth to mount a set of 2 way components and their crossover.  The outer layer was full size and the two inner layers were only an inch or two around the perimeter to get more volume. The whole thing was covered by a fiberglass panel that was covered in acoustically transparent cloth so that they ended up pretty much invisible.  I did have to take out a mounting bolt for the parking brake pedal so that it could swing inboard to clear the left hand enclosure.

In the rear, I applied 3 layers of fiberglass over the sound deadening tar stuff to encapsulate it as it was breaking up.  I did cut the openings to install 6X9's but from what I understand you may not be able to do that.

 I built a 10" deathbox from plans, http://www.decware.com/dbk10.htm  I didn't want a window rattler but did want good clean bass.

The four corners were powered by a 45WPC Alpine amp and the sub by a 100W bridged amp.

That car freakin rocked!  As it well should, what with the electronics costing $1000 more than I paid for the car.

On another install I tried building rings to mount speakers from the underside.  Sort of looked like tunnels from the topside.  Sounded so bad I never bothered to listen to it again.

You will never get any bass out of dash mounted speakers unless you can build correctly sized enclosures behind them and that is nearly impossible in an existing car.  If the stamped recess in the rear is shallow, you will never get any bass out of the rears either.  Speakers have to have the proper amount of enclosed space behind them and the sound waves from the back side can not be allowed back around to the front side.  This will cause cancellation and is sort of how Bose noise canceling headphones work.

I have heard of folks putting a sub in the trunk, "venting" the floor of the first aid compartment and propping the lid open a smidgen.

Michael


Forgot this link, http://www.crutchfield.com/c_3/Car-Audio-Video.html
They may not ship overseas but they do a good job with providing specs including mounting depth.

[koan]

I am really dissapointed with the base out of the system ... my suspicions that the issue is with only having a small box of air behind the rears.

The panel that separates the fuel tank area and boot space comes out pretty easily from memory, how about temporarily removing it and seeing if it has any effect on the bass?

koan

[TJ 450]

Indeed, you can only ever hope to get fake bass from the front 4" speakers. What I usually do is place a high pass filter on them, at around 100Hz, that makes them louder, more efficient and allows them to dissipate more power.

The Jaycar Response speakers are quite OK... I have the 12" Polycone sub from back in the day.

Tim

[Maat1985]

the kevlar response speakers from jay car are the 4" i have in the front and they have great clarity only prob is when the volume is too high they crackle alot and i think hat has to do with the space they are in and distortion cus i have heard them perform better in other vehicles.... as far as rear goes you cant go i have 51/4 rockford fosgate as i have said b4 and i have a 12"sub in the boot... have not yet ported a hole for the sub but atm i have the back seat out with no matting there either and the bass is increased greatly.... atm my system sounds absolutely awesome and you would think i spent more than i did..... i will be replacing the back seat and porting a hole through the parcel shelf and first aid kit well soon....

[craigb]

Koan, that panel is removed on mine, mainly because when sprinting they want to be able to access the valve on the LPG tank, and I can't be bothered putting it back in between. By what people are saying though, with a sub there is an issue with the fixed steel panel behind the seats more than having a great lump of an LPG tank in the way and allowing some sort of open channel to the cabin is the way to get around this.

My conclusion from what is here though is that the standard rear enclosures are a problem and cutting new holes into the rear shelf that utilise the boot is the best answer for me. I had removed my plastic first aid box to ensure the lpg tank clearance, so to go the sub road the best answer there could be to remove the bit of steel I put in place of the box and replace it with a mesh sheet that would hold the open weave carpet I have level and look normal (except when the base would be moving it!) and yet allow good passage for the sound.

[koan]

Koan, that panel is removed on mine,

I think I might have missed something, got the idea the only thing between backs of rear speakers and boot is the vertical panel, the one I suggested removing but by the sound of it that's wrong, there is a metal panel below the speakers that forms an enclosure for the speakers. Is that the way it is?

koan

[TJ 450]

There is indeed another panel beneath the rear speakers and in a way it does form an enclosure.

Tim

[craigb]

Yep that's right Koan and it is a very small enclosure. Actually I am not exactly sure why it is there. Will investigate but maybe I can just hole saw a big hole in them?

[Maat1985]

just removed the first aid kit well and cut a hole in my parcel shelf (not original one dont worry and coverd the hole with a speaker grille to allow the sub to pass through into the cabina and damn the increase in quality of sound is awesome......

[goldacre]

My previous 280SEL had a good setup that worked well and went along like this with advice from the Stratfields installer off Thomas Road in Perth:

Split system speakers in the front, they were Kickers and the sound was good, due to the windshield/dash set up in the Merc the splits were close to the listener and could be a bit tinny but experimentation with the  treble will fix that.

The rears were JBLs 5 & 1/4 inch as they had the shallowest depth and cleared the vacuum tank and the sound from them is good. The installer said not to put in spacers to maximize choice of speakers as he said it will give poor sound quality from his experience. He had worked on Mercs before.

Also the installer had the same headset as mine, an Alpine, so he pretty much fitted the best speakers in his opinion for the application and headset and i was very happy with the sound quality. 

With the Becker Tape system in the 450 starting to slow down i have made the decision to install the Alpine and look around for a speaker set up similar to before. Hope to have this done before the next West Aust group meet which is planned for a nice sunny day soon?

JG