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Stereo thoughts...
Posted: Thu May 29, 2008 10:06 pm
by wiglaf
I'm thinking of giving Sleipnir a stereo, if the cost of repairs on top of the MOT doesn't come out too high... and even then I want to stick to a fairly tight budget... I've read a bit about typical options, but don't particularly want to risk ruining a pair of perfectly good (ok... fairish) scuttle panels to fit speakers as described at
http://www.minormania.com/feature.php?id=1996&catid=-1. I also don't want to mess about placing other speakers elsewhere in the car, with even more room for complications.
It seems to me that a way of avoiding loss of sound quality due to that "less than optimum location", and sparing the panels from my bodging, would be to sit a pair of bookshelf speakers on the parcel shelf, pointing up and out straight at your faces. With a little luck, that should compete rather better with the lion-like roar of her mighty 948!
Has anyone else tried this?
Is there any reason I should be chary of connecting, say, a pair of these
http://www.argos.co.uk/static/Product/p ... PEAKER.htm to, say,
http://www.caraudiocentre.co.uk/product ... -23105.htm? (I won't necessarily be using these particular ones, or going to these shops, but the wattages match - which I assume is the limiting factor?)
If there's no compelling reason not to, I hope I'll be giving it a go - though using the living room speakers to start with, and getting a second set if it works. If not... no problem, nothing spent on speakers yet and I can take the conventional route
Tips on wiring in head units etc. welcome, of course, though I've a VHF enthusiast-friend lined up to help with that aspect of installation: you should see *his* car's radio setup...
Posted: Thu May 29, 2008 10:12 pm
by bigginger
It's how most pople do it, though preference is generally for car radio speakers, not domestic ones. No reason why not, though...
a
Posted: Thu May 29, 2008 10:26 pm
by alex_holden
I mounted mine very simply in those big holes under the dashboard using brackets made from pieces of plywood with a hole cut in them. There is room behind the glovebox liners for the magnets and they work very well with no rattling or buzzing even at very high volume. You can also see the stereo mounting bracket I made from a piece of steel sheet (the wiring is untidy but it works).

Posted: Thu May 29, 2008 10:49 pm
by alex_holden
BTW, another point, car stereos are usually designed to drive a 4 ohm load and house type speakers are usually 8 ohms. It's better if they are matched.
Posted: Thu May 29, 2008 11:03 pm
by bigginger
Car speakers are usually designed to be boxed in, btw, fwiw etc etc
a
Posted: Fri May 30, 2008 7:39 am
by alex_holden
I think this type is usually fitted to holes cut in a parcel shelf. On the previous car they were in (a modern hatchback), the trim panels rattled horribly if I turned the volume up high. They are something similar to this model I believe:
http://www.caraudiocentre.co.uk/product ... -21536.htm
On my Land Rover I had four sets of speakers; the ones at the back were small boxed ones meant to be placed on top of a parcel shelf and the ones at the front were larger ones fitted into MDF boxes I made myself. They were very loud (they needed to be!) but distorted the sound fairly badly at high volume. (And then the roof leaked and killed the stereo, but that's another story.)
Posted: Fri May 30, 2008 9:26 am
by IaininTenbury
alex_holden wrote:
On my Land Rover I had four sets of speakers; the ones at the back were small boxed ones meant to be placed on top of a parcel shelf and the ones at the front were larger ones fitted into MDF boxes I made myself. They were very loud (they needed to be!) but distorted the sound fairly badly at high volume. (And then the roof leaked and killed the stereo, but that's another story.)
sounds like a Land Rover does that! I had my CD player back to the shop 3 times for an exchange, before I realised it was getting wet. Then a water proof shield over it and its fine....
In the Minors, I use shelf mounted speakers, on the floor beneath the seats facing forwards which seems to work quite well. No cutting and drilling involved and you stick velcro patches on them they'll stick to the carpet. In the van they're just behind the seats at the front of the load bay which also seems to work ok.
Posted: Fri May 30, 2008 10:06 am
by wiglaf
So... what if the two 8ohm speakers were wired in parallel? I understand (I think - please, excuse my ignorance!) that that halves the impedence, so would mean they acted as 4 ohms?... what effect would this have? Risk of blowing speakers due to increased current?
I actually quite like the look of that under-dash down facing approach in terms of using the "right" speakers but keeping it as simple as possible, Alex... what's the sound like?
thanks for the help guys
Posted: Fri May 30, 2008 10:15 am
by alex_holden
That should work if the two speakers are identical. Obviously it means you have to buy and fit twice as many speakers or only use one of the stereo channels...
The under-dash speakers sound fine with the kind of thing I listen to (mostly Radio 2 and audio books). They sound better than they did in the previous car because they are mounted to solid steel bodywork rather than rattly trim panels.
Posted: Fri May 30, 2008 10:16 am
by wiglaf
...or just have everything in mono, and a wire running the width of the car?
Posted: Fri May 30, 2008 10:18 am
by wiglaf
Cheers Iain - that was sort-of the original plan when I first considered this (before the last MOT)... but since then I've found it hard to find the right sort of speaker (i.e. "boxed" ones not needing some kind of mounting, if you see what I mean?)
Posted: Fri May 30, 2008 10:27 am
by IaininTenbury
Yeah, I know. You don't often see the old style of shelf mount speakers these days. Car audios' moved on a bit from perching a couple of speaker boxes on the back shelf. Some smaller independant motor factors still have them though (we bough a new pair last summer for my wifes car) and its certainly quick and easy.
Posted: Fri May 30, 2008 10:30 am
by alex_holden
wiglaf wrote:...or just have everything in mono, and a wire running the width of the car?
Yuck. Stereo music sounds much better than mono IMHO.

Posted: Fri May 30, 2008 10:36 am
by wiglaf
tbh, I haven't heard a mono setup in so long...

Posted: Fri May 30, 2008 12:52 pm
by ColinP
I'd strongly recommend car speakers.
I'e fitted a pair of kenwood's in the trim panels - just above the parcel shelf. The sound is good, but more importantly, the speaker cones are a) waterproofed and b) designed to be shaken about....
If you use domesic speakers, the cones are not designed for the vibration that you get from a car chasis driven over our roads.
Top tips - make sure that the car is -ve earth; seriously consider a radio with a remote control (wired or wireless), make sure your radio can be turned off - many modern ones rely of the "Acc" terminal of the ignition switch - standard Minors don't have them!
Personally I find digital is pretty good - most of the time certainly I would not use LW/MW!
Colin
Edited for spelling - 9/10 must try harder
Posted: Fri May 30, 2008 12:52 pm
by AndrewSkinner
having the 8ohm speakers on a 4ohm output is absolutley fine!! it just means the amp will not be able to go as loud! Its when you put on speakers that are lower than the recomended output that you get problems.
Think of it like a tap. the tap has a recomended output, If you for example put a hose on it that reduces the output (e.g. your higher impediance speakers) then there is no problem, the water continues to flow just at a lower rate.
If however you put a hose on that is too big and draws too much water through the tap you get failure of components.
It simply means that if you go below the recomended impediance you will be drawing too many amps through the amplifier. Most modern stereos have thermal cut outs anyway and will turn off or turn the volume down before they blow!
Speaker wise alex is correct. speakers need to be in a calculated enclosure for best results. If you put a speaker in mid air there is not enough back pressure on the speaker from the box and so you will get distortion very quicly, coupled with tinny sound.
You either need to build a wooden box for them (get rough dimensions off the net for best results) or buy bookshelf speakers. I have a pair of 'Eltax Millenium' bookshelf speakers, they fit perfectly under the front seats pointing forawrd and the quality of sound they produce is incredible! nice clear crisp bass and it sounds like the sound is coming from all around you. I have had many comments made about them!
Another positive to that is that you dont need to adjust anything. the speakers sit there under the seats held in my the seat frame and the wires run under the carpet.
I got the speakers from Richer Sounds on deal for £15!! and they still have them
Colin, domestic speakers will take the bumping around easily. You are more likley to destroy speakers that are not in a sealed/calculated ported box as it will clip. When it clips you get the speaker moving in an oval motion instead of an in and out motion, this causes the coil to rub on the magnet short and overheat, prolonged periods of this will A) destroy the speaker or B) overheat the amp.
Good luck with it all and let us know how you get on!
Posted: Fri May 30, 2008 1:16 pm
by alex_holden
AndrewSkinner wrote:having the 8ohm speakers on a 4ohm output is absolutley fine!! it just means the amp will not be able to go as loud!
It isn't that simple. Impedance matching is important to get the optimum power transfer - 8 ohm speakers on an amplifier designed to drive a 4 ohm load will waste more power in the amp and could potentially overheat it. It will
probably work OK but it isn't really good practice.
If you put a speaker in mid air there is not enough back pressure on the speaker from the box and so you will get distortion very quicly, coupled with tinny sound.
I don't get significant distortion or tinny sound. You're welcome to come and listen to them at the National.
You are more likley to destroy speakers that are not in a sealed/calculated ported box as it will clip.
They aren't clipping either...
Posted: Fri May 30, 2008 1:24 pm
by AndrewSkinner
Alex if you put the output from an amp into a higher output it wont overheat?? Simple formula Volts/Ohms gives you the current. If you increase the resistance there is less current flowing around the circuit and therefore a smaller audio signal. Becuase of the lower current there wil be even less heat generated.
You are thinking of when you put a lower impediance speaker onto an output that is rated higher. The components are designed to take a maximum current, when you put in lower impediance speakers you lower the resistance in the circuit and therefore increase the current. Its this increase in current that then causes components to get too hot as they are being pushed beyond there recomended limits.
refering to your speakers you must have some nice speakers in there

but you will find that they are not working at there optimum. No speaker is designed to run in thin air. otherwise I wouldnt have spent years and years trying to calculate optimum speaker cabinet sizes.
This is my pride and joy
http://mymorrisminor.weebly.com/other-p ... eaker.html

Everything calcualted to the mm

sounds incredible!!
Posted: Fri May 30, 2008 2:09 pm
by wiglaf
So where in the car's that one mounted? After all it was calculated to the mm...
... maybe I should keep my puns to myself?
Posted: Fri May 30, 2008 2:20 pm
by jonathon
Here's a link to some speakers made for 'Moose' belonging to the Minor Mania website ownerhttp://minormania.com/feature.php?id=1983&catid=268&pg=4&cpg=2#pic
This system comprised of Focal front speakers with seperate tweeters and cross overs linked to a Kenwood head unit and two Rockford Fosgate amps, rear speakers were Infinity 5x9's.
The sound was stunning with any form of music, especially Fanfair to modern man' at 7.30am at the National at Harewood house.
