Stereo Planning Questions

[Wacky]

Hi Guys, this might be a long thread, but hopfeully not...I'll try to keep it concise.

I am in the very early stages of planning a better aduio system for my new (new to me) VZ sedan, and I need to bounce some ideas of people in the know.

Firstly, I am planning on keeping the headunit stock, except for upgrading to a 6 CD headunit from my single CD unit. I will then be doing Phreddy's Line-Out and AUX IN mod. My understanding is that this will give me 4 line outs, being Front Left, Front Right, Rear Left and Rear Right - correct me if I'm wrong.

What I would like to do, is have splits in the front, with woofer in the front doors and tweeters on the dash (or in the vent in the corner). I currently have speakers in the rear doors, but nothing on rear shelf. I'd like to disconnect the rear door speakers and put some 6" speakers in the shelf for rear fill - not 6x9s. I am led to beliee I should be able to get 6" into rear shelf without risers/spacers etc, and only have to remove the pre-cut preforated plate?

I'd then like to have one or two subs in the boot. I was thinking two 12" in molded boxes in the rear corners facing towards the back seat.

The music we listen to is extremely diverse, and I mean it. Matchbox 20 to Sinatra to Classical to Country (only a bit) to Jazz (like Norah Jones & Katie Melua plus classic Jazz from 50s) to Gunners to Hawaiian to Metallica (me ) to Blues....it's all over the place. Yes, we are over 30 - might explain our bizarre tastes

My goal is to be able to play loud, but not smashing windows loud, but clarity is up there on my priority list.

Are two subs better than one? I've read that they should be identical subs to avoid chances of cancellation. Also, are sealed molden boxes in the corner okay? Like this : Box in Ebay.

Depnding on how big the box(es) need to be, I might need to have them removable for going on trips when the wife decides she needs to fill the boot with baby **** (he's 20 months).

What I am initially thinking is one 4 channel amp to run the front speakers (do the tweeters just come off the same wiring as the woofers, with a filter to block the lower frequencies?) and the rear speakers, plus another amp to run the single or pair of subs.

Both amps would live in the boot, but would need to be protected from strollers and shopping (I'd have to put a grill over sub cones for protection too) - not sure if they can be mounted under the parcel shelf using reinforcement of some kind.

Assuming the above is a good plan, this would mean the 4 line outs would be wired through to the boot, and then wires back to the front for the front speakers?

What do I used for the sub(s)? Would I just jumpr them from the linouts, as in split the lineouts with a terminal block or something?

If i'm using one sub, do I have to choose either left or right/front or back channel? or is there some way of combining them without interference, as in take signal from both left and right rear linouts?

At this point I ahven't looked into the brands or power requirements etc of the speakers or amps I want to use, but if anyone has thoughts on that subject, let me know. I always liked the Jaycar gear, for price and quality - not top notch stuff, but reasonable price for what you get - ie, you aren't paying for a name.

Sorry for the long winded post, hopefully I made sense.

I might do up a diagram as well to explain it better if needed.

 

[Wacky]

Pic added - hopefully it makes sense

Pics always help

 

[Phreddy]

All sounds like a great plan Wacky - although you'll find that the punch-outs in the parcel shelf are in fact for 6x9 speakers - so if you're stuck on placing 6" units there, you might need to use some kind of adaptor plate. (although you wouldn't really need to buy it as such - you could make something up from either steel sheet or MDF - but be careful with MDF though, if it's too thick the speakers will foul on the parcel shelf trim)

The other thing is that with the drive to your sub, you would really need to decide whether you want that to come from the front or rear line-outs, after going via the "pass through" inputs from your 4 channel amp. (usually the pass-thrus will only be used on 2 of the channels) With the setup I have, the sub amp is driven from the front channels, as the rears are only used for fill anyway. The front channels of the 4 channel amp are running high-pass, and the 2 channel amp I use for my sub is set in low pass mode. The other 2 channels in the 4 channel amp are just set to full range for the back fill speakers. If you choose only a single sub, it's generally fed from two channels (left and right) and mixed together within the amp itself - particularly if it's a 2 channel amp in "bridged" mode.

Oh, yes you're correct about the tweeters for your splits - they don't require separate channels on the amp, they are simply connected to the high pass outputs from the crossover. (that's the little filter box which sits between the amp output and the actual drivers)

My amps also live in the boot, and are protected from damage by the fact that there's a 5mm aluminium checkerplate "shelf" mounted below the parcel shelf itself (on a piano hinge so the whole affair can be swung down for maintenance), and the amps occupy the space in between. It has the added advantage that the aluminium panel gives a little extra heatsinking for the amps, so they never break a sweat! (by the way - the amps are a 4x50WRMS and a 2x80WRMS Response units) I've attached a couple of pics so you can see what I'm on about. One of them shows the plate swung down in the "maintenance" position.

My sub as you can see fires backwards, and the box (which I custom built) covers basically the whole width of the back seat - it's not very deep though, so it doesn't intrude too much into the boot space. If need be, it can be removed in less than a minute - there are 8mm "thumb screws" at each end securing the box (matching "t-nuts" on the inside of the box for these to thread into), and a quick-disconnect Neutrik "Speakon" plug so the wiring can be disconnected with no risk of shorting out. Heh - works for me, anyhow. Doesn't give me the sort of bass which will peel the roof off, but that's not what I'm after. Certainly good enough for a mobile massage though!

Cheerz Mate, all the best with your project.

 

[Wacky]

Wow, thanks for the detailed response Phreddy !

Do you think the Response gear is decent value for money? I love that shelf you have...that looks nice and safe.

I saw that the punch outs were oval, but got the impression from other threads, that to actually put 6x9s in you have to use risers for some reason. Well, if 6x9s fit in easily, then I'll look at using those.

The other thing is that with the drive to your sub, you would really need to decide whether you want that to come from the front or rear line-outs, after going via the "pass through" inputs from your 4 channel amp. (usually the pass-thrus will only be used on 2 of the channels)....

I am understanding that you have the Sub amp inputs are coming from the 4ch amp after being passed through? Or are they still coming from the front lineout signal direct?

Now from what I am reading, you have all speakers amped, however you have the fronts set to only receive higher freqencies, as the sub covers the lower ones (and with low frequencies, left/right doesn't mean anything?), but the rear speakers are high and low frequencies for fill ?

If the sub is removed (and as you said you have a plug that ensures no short outs) does the amp need to be unplugged to prevent damage to it? Can you also adjust the rears (I guess via Gains control) to give some of that bass back?

Is that a 12" sub? If you had two, would it really make much of a difference?

Thanks again for your advice !

 

[Phreddy]

My plasure Mate!

OK, 6x9" drop straight into those punch-outs - no risers needed. (maybe that refers to earlier models, where the parcel shelf holes were in fact 6" round)

My sub amp inputs do run from the front channel pass-throughs. That's effectively the same as running direct from the front line outs anyway - if you look inside these amps, the connections from the inputs are looped directly to the pass thru outputs. There's no filtering or gain control applied to those at all.

You're kinda correct about the front frequency range, but the crossover I have set at about 100Hz which is pretty low down in the spectrum. Yes indeed, the directionality of low frequency sound isn't important - especially down that low in the range. When the sub is removed you don't need to unplug the amp at all, it won't be damaged by operating when the speaker isn't connected. It pays though to set the crossover switch on the front channels to "full range" when the sub isn't connected. If I was to fit another sub (and yes, it's a 12") I think it would make a difference, but I've personally found that the single one does the job for me. I'm not into full-on bass thump, more a "balanced" overall sound. Like yourself my tastes are quite varied, and the system I have seems to provide a nice balance.

Lastly, I do indeed think the Response gear is quite good. It's certainly a long way from top shelf, but when it comes to bang-for-buck it's almost impossible to beat. I see that they now have quite a nice looking five channel amp, which would fit your needs pretty well perfectly. (I'm not sure, but that one might overcome the "two channel only" drive to the sub problem. I'm willing to bet that with proper configuation of the amp, the low pass filtering can appply to all four channels, and the sub drive mixed from all four inputs. Don't quote me on that 'coz I haven't seen one yet, but if I was designing it that's what I would do!)

Anyhow, have a great holiday Mate - if I can help with anything else let me know.

Cheerz! :thumbsup:

 

[Wacky]

Again, thankyou, it all makes sense now !

I saw that 5ch amp, but didn't know how it would work with the system in my head....looks like I'll have to pop down to Jaycar soon and checke it out and try to get full specs.

Hey, when I'm ready to get the audio mod kit - and the blue LED mod kit - what's the easiest ? Shoot you a PM, or an email to the address on the website?

EDIT: Oh, do you recall what guage wire you used? From the pics, it looks like the OFC (clear coated) stuff for the speakers (I've used that stuff before) but what did you use for the line-outs (that everyone refers to as RCAs, even though I always understood RCAs to be the plugs, and they don't necessarily mean it's a low-level line-out)? I don't mind making up my own (rather than pre-made), as long as I know the right stuff to get for the requirements. Are you power and earth 8-guage?

EDIT 2: Looks like maybe power is 4-guge into two 8-guage? Or 2 into 4?

 

[Phreddy]

Either method of contact will work - whatever floats yer boat!

I made up my own low level cables, but it's actually cheaper to buy them pre-made. If you want to make up your own, I used the fig 8 double shielded stuff from Jaycar - cat number is WB1509. It also has a central single lead wire, which I used for the amp remote signal. (several people will tell you not to use it for this, but I've done it in several installations and never had a problem) Don't forget that you'll need double length of this, because you have four channels to run. I used the high q gold plugs to terminate both ends, PP0236 & 0237. (they're solder type plugs - I don't trust the "solderless" type) To be honest it will cost you more to make them yourself than to buy decent ones pre-made. Up to you though!

The power feed is a single 4G from the battery (via a 80A Maxi-blade fuse), and splits to two 8G cables to the amps. (if you end up using the 5 channel amp, you would just run the single 4G cable to it)

Cheerz Mate, later!

 

[Wacky]

Thanks Phreddy ! With pre-made, I'd be too worried about getting them too short or excessively long. And I like the idea of the central wire for the remote. In your pics, what are the wires plugged into the amp between the power and earth wires? I thought these were the remotes - or are they, and you extracted them from the cable prior to entry into the boot?

Do you recall how long the cables were that you made up? I'm assuming they run from headunit, across under glovebox, and down the left hand side of the car into the boot?

 

[Phreddy]

Actually, with my line out mod, the RCA cables don't run all the way to the back of the head unit. (once you see the kit you'll see what I mean)

Because there's almost no room at all behind the unit, part of my mod involves the line out cables running from a specially crafted connector mounted to the cradle through short (approx. 30cm) cables out to the sockets, which come out behind the lower left panel of the console. From there the RCA cables run along the transmission hump and under the back seat, then along the edge of the centre fold-down opening behind the trim up to the parcel shelf. I did extract the remote wires at that point, and yes it is the remote wire that runs between the +12V and ground cables. I have to admit I did go to a lot of buggering around!

You could run the cables along the left side of the car, but it would mean the cables need to be longer. I ran my main power feed along the right side, but really it's easier to run it down the left - and it's not a good idea to run the RCA cables next to the power feed, 'coz you can end up with noise being induced into the signal lines. In all of the installs I've done I've run the cables along the transmission hump, and never had any trouble at all with induced noise. That is also the advantage of making the cables, 'coz that double shielded stuff - whilst it's a bit spendy - is damn good quality. In fact, I would consider it to be "triple shielded", as there's two layers of braided copper shielding spearated by another layer of foil shield. Not much interference gets through that!

Ummmm - as for the length, I can't quite remember! I know 4 metres is a little too long, but 3.5m might be a little short. If you make them 4m and leave the plugs off the amp end, you can trim off whatever excess you have before soldering the plugs on. (that would be 8m of cable in total - I think it's about $3.60 a metre, then you need 8 plugs.)

There ya go bloke! Catch up with you later. Cheerz!

 

[Wacky]

Hey Phreddy,

A quick question, where'd you get hte checker plate for your shelf? I've found some steel suppliers but not sure if (a) they sell to public, or (b) if they are open on weekends.

I doubt Bunnings sell it either.

I have just purchased a 6cd HU so once the seller sorts their stuff out, I'll be contacting you about the mod.
It looks like I will be using the same, or similar amps, and possibly the new Jaycar 12" sub, but I'm torn between the Alpine Type R splits and either set of the jaycar splits (there's a $149 set and a $299 set, but I can't find full specs on them). For the rears, I'll probably just use a set of Jaycar 6x9s.

Just another question about the mod. If I do the mod, can I still use the normal outputs? ie, use line outs for splits and sub, but leave the rears as they are for now? If so, then I'll leave the rear door speakers running off the HU, and to the 6x9s last, and at that time, I will disconnect the rear door speakers (or leave them connected if it's not going to cause any problems). How would the volume of speakers be affected, with some going via lineouts/amps, and others still via HU? is it just a matter of balancing?