Adding sub whilst keeping Mac

[RAN94A]

Hi guys,

Just wondering from what ive seen around the forum it looks like some of the guys have been able to add a subwoofer to their stock sound system without ripping out all of the mac unit.

Im not all that fussy about my sound and the Mac unit sounds far better than alot of stock stereo's but i really really miss the punchy bass i had with a big sub in my last car.. im just wondering how i would go about adding a sub... but keeping as much of the mac intact as possible??

Cheers,
Gavin.

(PS i drive an MY06 3.0)

[Boxer]

I did exactly that - My days of large car stereos are in the past and I cant be stuffed removing all the Alpine and Focal gear in the Prado into the Subaru. Sooo I simply disconnected the factory sub in the boot and extended the wiring to connect to a 12in Eclipse sub in a sealed box and faced it back towards the hatch (I drive a wagon) and I run it out of phase.

Much deeper and punchier bass being a sealed unit.

However choose your Sub wisely - you will need a very efficient unit as the Mac amp is grossly underpowered.

Do a search I posted pics of it ages ago in these forums

[cpitts]

You've got maybe 35W to play with, so pick an efficient unit and put it in an exact box it requires and you should be good for a solid improvement. More than that will see you having troubles. I really should look to making the McIntosh DIN breakout cable, there'd be SUCH a good market to be able to split out RCA's from the stock DIN to let people run decent amps.

[GT_Tony]

(may be a silly question)

can you unplug the sub and use the wires as a High Imput into an aftermarket Amp? thus being able to run whatever sub you wanted?? (within reason)

[cpitts]

Yes you could use speaker level outs.

[RAN94A]

*forgive the noobness im not hugely technical*

I wasnt really looking at like custom choosing a specific sub and then custom mounting in a special box or anything i was more looking at like.. a slimline sub, pre-boxed from a store (pioneer/kenwood etc)
Would this sort of set up sound ok/work ok with the low output mac amp??

Alternatively.. what process is involved in replacing the Mac amp? (lamemans terms)

Or RE: Gt Tony you can use the wires running from the mac amp to the sub... to plug into ANOTHER amp... to plug into a sub??? and this wouldnt damage the sound system at all or anything? Would you need a special kind of amp or converters or anything??

apologies again but im trying to get my head around it all

[cpitts]

*forgive the noobness im not hugely technical*

I wasnt really looking at like custom choosing a specific sub and then custom mounting in a special box or anything i was more looking at like.. a slimline sub, pre-boxed from a store (pioneer/kenwood etc)
Would this sort of set up sound ok/work ok with the low output mac amp??

Yes, a well selected (ie: efficient and able to drop into the standard hole for sedan, or small box for wagon if u want) will more than improve things.

Alternatively.. what process is involved in replacing the Mac amp? (lamemans terms)

Unforunately, the answer is cash and a good quantity of it. The plug that goes from the HU to the amp isn't a standard connector for new amps. As such, there's no 'easy/cheap' way.

You're basically looking at:
1. custom RCA's made into the McIntosh HU
or
2. new head unit, AV panel plate (the faceplate around the new HU)

Or RE: Gt Tony you can use the wires running from the mac amp to the sub... to plug into ANOTHER amp... to plug into a sub??? and this wouldnt damage the sound system at all or anything? Would you need a special kind of amp or converters or anything??

apologies again but im trying to get my head around it all

Think the last point answers that bit.

More than happy to answer these questions, been there and explored most things so far.

[gordy]

The Mac HU uses discrete outputs to the amp, even if you cut the cable (due to the special plug) a standard amp is not going to work. I think alpine has a product to fix this but its going to get expensive should you want to go down this track.

[cpitts]

The Mac HU uses discrete outputs to the amp, even if you cut the cable (due to the special plug) a standard amp is not going to work. I think alpine has a product to fix this but its going to get expensive should you want to go down this track.

Gordy, can you expand on the statement 'discrete outputs'. Do you mean line level or RCA level outputs? Or is it a proprietry signal of some sort?

A schematic breakout of the cable (as provided by Clarion, the maker of these units) shows explicit Front R, FL, Rear R, RL and Sub channels coming down from the HU to the amp, just in a DIN cable format. Admittedly, the outputs from the amp are balanced (hence 3 wires per channel + / - and Shield)

If you have any greater detail than this, I'd be REALLY interested in seeing it.

[tehx]

Do you mean the outputs, from the MAC, to the Amp are balanced? As apposed to the outputs from the Amp to the Speakers.

To get a balanced system (+4 dBm) to an unbalanced system (-10 dBv) all you need is a couple of resistors, typically a 3.8k Ohm and a 1k Ohm. Will cost you about, $0.20
Google 'balanced to unbalanced audio', you will find schematics etc. Going the other way (eg. unbal to bal) requires a little more work, typically an unbal to bal amp, which can be made for like $30. Jaycar / Dicksmiths may still sell these in kit form. Place the resistive network close to the unbalanced Amp if you can.

[cpitts]

Yes. HU to Amp is Balanced.

Amp to Spks uses twisted pair. Another interesting EMI protection process.

There's quite a bit more thought in this audio setup that in other Subaru's I've pulled apart. Clearly they've had more consultation than normal.

[tehx]

To further my last post – the Jaycar Amplifier kit (link below) converts bal to unbal and vice versa. It will allow you to use the OEM balanced amp on an unbalanced HU and also the MAC HU (balanced) on an unbalanced AMP. The bonus of this, as apposed to the resistive network I posted about previously, is that you retain a balanced line right up to your AMP. If noise is a problem in the transmission line (from HU to AMP) this will be the better solution.

Go to jaycar.com.au and search for kit/catalogue number: KC5468

Oh, and place the bal/unbal amp so as to maximize the cable run that is balanced and minimize the run that is unbalanced.

[RAN94A]

So tehx.. what your saying is (just to be sure).. we can buy this kit.. install it between the H.U and the amp and we can then install any amp we want and then hook up a sub to it.

[cpitts]

The Jaycar kit looks like it converts 1 RCA from Bal to UnBal which is great. But you've got 5 coming down from the HU to the amp, so that's 5 x the price of ~$30 per unit or at best case you may need 3 of em if there's 2 channels (fronts, rears, sub).

I'll just get an amp that does Balanced inputs. The extra $150 will cover the cost difference in most cases once you're at the reasonable end of the market.

[tehx]

I need to get hold of the schematic to be perfectly sure. From all accounts the description on Jaycar say's it will do unbal to bal and vice versa. I phoned them but they would not FAX it to me. You can go down to the store and have a look at the schematic though. I might pop down there on Sat and take a look.

Below is a diagram of a balanced to unbalanced circuit, using two resistors. I have made a few of these in the past and they work quite well. You will need one for Left and another for Right - so 4 resistors in total. Should be under $1 to make. As mentioned if you need to run a balanced cable right up to AMP, due to excessive noise etc, then the bal to unbal amplifier is the way to go.

I usually work with XLR type connectors in this environment so the two resistors fit inside the XLR connector. You might be able to fit the two resistors inside an RCA connector too.

Edit: This circuit is for a line level (+4) balanced system. Not for speaker wiring (eg. from amp and or HU to speakers)