Adding compact Amp to Base Stereo set up HELP

Ferglar · Post by **Ferglar** » Wed Oct 18, 2017 10:44 am

Right, I'm pretty sure I have exhausted every search option on this topic and not found the answer so bare with me...

I've finally acquired a 2007 roadster (just 7 years after my initial test drive) after the starting a family put my idea on ice!

I have the base stereo 6 speaker set up. After putting in an aftermarket stereo and subsequently removing due to ruining the look of the dash I want to improve my sound.

So I've ordered some 2 way 6x9's to go in the rear cubby hole's which I plan to run from the rear speaker wiring and not use the factory speakers.

I have also ordered 4" speakers for the doors to replace the current blanks which I will run off the tweeter wires.

Now to run this I've ordered a Pioneer GM D1004 compact amplifier that looks like it can run directly from the stereo with a din adapter. It's here...

https://www.pioneerelectronics.com/PUSA ... s/GM-D1004

Now will this work?

Or have I ordered all the wrong stuff?

I know dangerously little about car audio and amp's so ideally want to avoid setting fire to my beloved zed!

Any advice would be much appreciated! Thanks

ph001 · Post by **ph001** » Wed Oct 18, 2017 11:19 am

Amp has the auto turn on for speaker level input which is important but why have you gone for 4 channel? 75db signal to noise ratio is really bad. In terms of quality this is better but it is more cash...

Hertz HCX 690 3way 6"x9" coaxials..... http://www.caraudiodirect.co.uk/hertz-h ... al-speaker
Hertz HCP 2X amp http://www.caraudiodirect.co.uk/hertz-h ... -amplifier

The HCP 2X is avail from Ebay brand new for £200+postage at the mo

Ferglar · Post by **Ferglar** » Wed Oct 18, 2017 11:26 am

Thanks for getting back to me!

I know nothing about amp's! Zero

I think this can be run as 2 channels or 4. It's pretty cheap and cheerful but I liked the fact it's compact and has the auto switch on thing so easy to wire.

If I run this as 2 channels does that improve things or is this just a bad idea?

ph001 · Post by **ph001** » Wed Oct 18, 2017 11:29 am

No point in running a 4ch amp bridged into two if all you need is 2ch. Certainly not the optimal way to run it as it reduces your signal to noise ratio even further. How much did you get it for?

Ferglar · Post by **Ferglar** » Wed Oct 18, 2017 11:33 am

Just under £80. I don't understand any of the channel business to be honest.

I just wanted something that's easy to install with the factory stereo. I'm not putting any subs in and trying to keep costs down where possible. Just adding rear 6x9's and 4" to the doors.

I have an underseat sub but I can't think of good use for it in the zed!

ph001 · Post by **ph001** » Wed Oct 18, 2017 11:50 am

Understand. You will still get a good improvement with the Pioneer, but it's pretty bottom end in terms of quality. Would recommend lining the 6x9 enclosure with dynomat (or equiv) and seal any holes. Part fill the enclosure with polyester fibre (polyfill) or rockwool.

What speakers did you go for?

Ferglar · Post by **Ferglar** » Wed Oct 18, 2017 11:57 am

Cool, done the baffles so need dynomat! Never thought of putting insulation in though! Do you not want the air there for the speaker to use or do you want to minimise the open space?

Went for MB Quart ONYX OKC169 for the 6x9 and Hertz DCX 100.3 for the doors. Figured I could cut out the factory rears once the 6x9's are in!

Thanks for taking the time to educate me! Love my tech and installation but completely fresh to this side of things!

ph001 · Post by **ph001** » Wed Oct 18, 2017 12:05 pm

The polyfill doesn't really reduce the amount of air volume very much at all but 'damps' the standing waves from behind the speaker and so effectively increases the capacity of the enclosure. You need to make sure it's fairly well sealed as the air vents on the rear trim create a short direct path between the rear and front. If the speaker can move air through the rear cubby, through the air vent and to the front then you lose all the speaker efficiency in the bass region. Midrange isn't affected much and it doesn't affect the treble at all mind.

Ferglar · Post by **Ferglar** » Wed Oct 18, 2017 12:09 pm

Wow, that sounds good to me!

Have I messed up much with the speakers?

ph001 · Post by **ph001** » Wed Oct 18, 2017 12:16 pm

Ferglar wrote: ↑Wed Oct 18, 2017 12:09 pm Wow, that sounds good to me!

Have I messed up much with the speakers?

OK I guess, pretty bottom of the range but if you are on a strict budget they tick the box for entry level. You'll have fun fitting those 4" in the door (will need an adaptor plate). Wire them directly in parallel with the door tweeters.

The 6x9 rears you will obviously have to make a baffle plate for (mdf probably easiest), then snip the wires going to the 4" rear speakers and use that to feed the speaker level input to the amp. Make sure you fuse the power feed if coming directly off the battery (which I assume you will be). I'd locate the amp vertically on the rear bulkhead for best airflow. Some people like to hide it under the boot trim but that's not good for heat build up.

If you then dremal the existing cubby hole box covers, you can put some speaker cloth over the opening and snap them back into place for a nice neat install.

Ferglar · Post by **Ferglar** » Wed Oct 18, 2017 12:29 pm

I got the 4" speakers from a great "how to" on here. They used some 10mm self taping screws to do the top holes and used the bottom 2 factory holes really nicely. 6x9's look relatively straight forward definitely going to pop the trimmed cubby holes back on. Like the open look but probably makes more sense to put fabric on!

When you say rear bulkhead do you mean the wall of the boot separating me (cabin) from the boot or the rear wall of the boot (very back of the car)?

How does the amp connect to the factory stereo? I have a din adapter which I used for the aftermarket stereo, does it run to the speaker block of that?

Sorry for all the questions, you clearly know your stuff!

Magicarcher · Post by **Magicarcher** » Wed Oct 18, 2017 12:31 pm

PH001 makes good points.

Some other things to consider about:

The 4" mids you are adding will need to closely match the sensitivity of the footwell speakers and the tweeters. Often aftermarket speakers have greater sensitivity that OEM speakers (sadly I can't tell you what the sensitivity of the standard speakers are, I chose the replace them). If your mids are too much higher you will get higher volumes out of the midrange speakers than you do out of the tweeters and bass speakers. This may give a perceived reduction in bass from the footwell speakers. Though personally I would prefer that to having just bass from your feet and tweeters at earline. Best solution is remove existing front speakers and replace with 3 way system with crossover (though a lot more work!)

Personally I wouldn't fit 6x9 in the rear cubby (there are many who will disagree with me I am sure). The bass you get out of a speaker is not simply a function of the size of the cone, but also the relationship between the speaker parameters and the enclosure. The rear cubbyboxes from memory are about 6L which is really not very big, this will dampen your speakers considerably and raise the effective resonant frequency and reduce the transient response (hence reducing bass). Personally I would go with a long throw 6" driver unit designed for small enclosures. Such a setup will generally provide better bass than an overdamped 6x9.

Re adding damping to the enclosure, surprisingly this has the effect of increasing the effective volume (providing you don't go over the top) for a sealed enclosure (25 years ago I used to know the reason why, but it has long left me) despite in reality giving you less volume. As PH001 says it should also reduce standing waves in the enclosure. However damping is generally not recommended if you port the enclosure.

ph001 · Post by **ph001** » Wed Oct 18, 2017 12:33 pm

Yes, by rear bulkhead I mean the wall separating you from the boot. In terms of connecting the amp to the stereo...well you don't as such. You just connect the speaker level inputs on the amp to the snipped wires that were going to the 4" speakers in the rear bulkhead. Don't worry about losing the sound from those speakers, they are complete trash! You shouldn't need the DIN adapter at all.

Ferglar · Post by **Ferglar** » Wed Oct 18, 2017 12:36 pm

Hi Magicarcher!

And welcome to car audio for idiots!

Thanks for that! I think what I'm looking for is the best I can do relatively easily on a budget.

What are 6" drivers or what do I look for on Google? Are they 6" subs?

Thanks again for your time and knowledge!

Ferglar · Post by **Ferglar** » Wed Oct 18, 2017 12:37 pm

ph001 wrote: ↑Wed Oct 18, 2017 12:33 pm Yes, by rear bulkhead I mean the wall separating you from the boot. In terms of connecting the amp to the stereo...well you don't as such. You just connect the speaker level inputs on the amp to the snipped wires that were going to the 4" speakers in the rear bulkhead. Don't worry about losing the sound from those speakers, they are complete trash! You shouldn't need the DIN adapter at all.

Right, so that connects the 6x9's to the amp, but what about the front speakers (factory and added door one's)?

Z4-forum.com

Z4-forum.com