New "Almost OEM" audio upgrade

[esses]

I've mentioned a few times that I'm on a mission to restore my 2001 M Roadster. After 14 years on the road and 90k miles (many in the desert heat of Phoenix,AZ), there's a lot of small things that need to be fixed. Frequently, this type of endeavor provides the opportunity to not just repair, but also upgrade.

That said, I REALLY am trying to keep the car's reasonably as close as possible to stock. Unfortunately there's not a whole lot of aftermarket head units that look stock, so picking one wasn't easy. But knowing this, we made custom harness adapaters. At the end of the day, not a single wire was spliced, not a single panel was cut, not a single hole was drilled. So setting things back to stock (or some mixture of stock/aftermarket) in the future would be relatively trivial.


So that said, here's equipment that fits in all the factory mounting spots... and the only thing that needed fabricating is a rear subwoofer box and a rear console panel. Pretty trivial.

Hertz Digital Amp - HDP5 - Fits perfectly where the manual was stored.


Super tiny modification (nick a corner) to the mounting bracket of the Amp itself. You can see it in the top left corner of the AMP where wires are routed


Cleaned up stock wiring with old amp removed.


Busted old speakers. I had 4 like this, including the sub.


I can't seem to find the build pics, but I replaced the component speakers (even the tweeters which some vendors claim are hard to find) without any major modification with the following.
Hertz Hi-Energy 6 1/2" component - HSK165
*insert boring pic that looks the exact same as stock here*


For the sub, we used
Hertz Energy ultra flat 8" subwoofer, 200wrms -ESF20
Box Parts


Test Fit


Finished and trimmed!


Now for the parts that are visible.
I chose to go with the Alpine - HD149BT. While it wasn't my first choice, timelines / availability of other units basically made this choice for me. In the end though, I'm pretty satisfied with the overall look. The color match is dead on, and there's enough blue / shiny bits in the rest of the console so as to blend pretty well.

Added a USB port, Aux Input, and extra 12V plug next to the power top switch with this custom little trim piece. No more wires all over the cabin! USB/Aux are run up to the front headunit so everything is controlled naturally.


Want to see what it looks like? You mean you didn't notice it in the pic above? Scroll up!

And the rest of the headunit

[legend921]

I like the way you ran the wires. I also thought about getting the 149BT as well since it is pretty simplistic in design.

[BimmerBreaker]

Maybe my eyes are broken but that center gauge looks unfamiliar to me, what is that? is that what the S54 voltmeters look like?

Im glad you chose one that illuminates amber. Thats a very good choice imo

[MartyBtoo]

Maybe my eyes are broken but that center gauge looks unfamiliar to me, what is that? is that what the S54 voltmeters look like?

Im glad you chose one that illuminates amber. Thats a very good choice imo

It's an outside ambient temperature gauge.

Marty

[esses]

It's an outside ambient temperature gauge.

Marty

And yup, that's a stock S54 center console.

[dkindig]

I would love to hear how you fabbed up the custom panel. I'm adding in a 5V 10A dc-dc converter and want to put in a quad USB jack plate as well as a line-in connector...

Also, your opinion of the Hertz subwoofer? Does it do well in the limited enclosure volume, and is the 1/4" wall thickness of your enclosure working okay?

[crashgordan]

Looks awesome. Nice work
and how's the sound?

[robb1887]

I'd be a little concerned with the amp under the carpet... thats not a lot of air circulation for cooling. Just my 0.02 as a previous ICE installer/sales.

[BladeRunner919]

I'd be a little concerned with the amp under the carpet... thats not a lot of air circulation for cooling. Just my 0.02 as a previous ICE installer/sales.

I was wondering about that. I'd thought of putting an amp where the toolkit is (non-///M) with a 'false floor' above it giving a small amount of clearance so I can still carry stuff on the boot, but was worried about cooling. Is there any way to do that and deal with the cooling adequately?

[esses]

I was wondering about that. I'd thought of putting an amp where the toolkit is (non-///M) with a 'false floor' above it giving a small amount of clearance so I can still carry stuff on the boot, but was worried about cooling. Is there any way to do that and deal with the cooling adequately?

This is a very fair concern. I had the same concern. Especially as from personal experience, I know it gets REALLY warm in the trunk under normal driving conditions... with the exhaust and diff nestled right up against the trunk floor.

That said, I went with a digital amplifier (HDP-5) for exactly this reason. Digital amplifiers are MUCH more efficient and run MUCH cooler than their analog counterparts. (As a side benefit, they're A LOT lighter too )

Here's a good write up on why digital amplifiers are much cooler: http://www.audioholics.com/audio-amp...dio-amplifiers

Secondly, the location we picked is actually better for air flow than the stock amplifier location for 1 main reason. There's actually an opportunity for some great airflow there "under the carpet". There are 2 vents on either side of the trunk of the roadster that vent into the well behind the quarter panels. I assume the factory has these for when you slam your trunk shut. The thing is... THEY ARE HUGE!! (top of the 2nd pic below) So you can rely on either convection to let excess heat out, or should I experience some problems, it'd be truly trivial to throw a small 12v $40 computer fan that's switched on/off with the amp itself.

Check it out. You can see the huge cavity that flows under the cross member next to the amp (top of both pics below). We routed wires into it. you can see the large wheel well vent just on the other side of the cavity. (In fact, if one wanted to add an audio processor, that would be a great place to do so)





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I would love to hear how you fabbed up the custom panel. I'm adding in a 5V 10A dc-dc converter and want to put in a quad USB jack plate as well as a line-in connector...

Also, your opinion of the Hertz subwoofer? Does it do well in the limited enclosure volume, and is the 1/4" wall thickness of your enclosure working okay?

I WISH i had good fab abilities. I'm an electronics guy I had the small panel and sub enclosure fab work done by a highly reputed local shop. HandCrafted Car Audio They're very reasonable for the quality of work they do (read not-cheap, but not insane), super straight forward and are willing to prioritize what's important to you (OEM+ appearance in my case). I have no connection with them other than being a VERY satisfied first-time customer.

The sound is LIGHTYEARS ahead of the stock harman kardon system, but let's be realistic... it's a roadster The sub hits CLEAN. It's not "boomy" or anything. Honestly, it just sounds like deep bass but you can't really tell it's coming from a sub. Which... IMO is just right.

[dkindig]

This is a very fair concern. I had the same concern. Especially as from personal experience, I know it gets REALLY warm in the trunk under normal driving conditions... with the exhaust and diff nestled right up against the trunk floor.

That said, I went with a digital amplifier (HDP-5) for exactly this reason. Digital amplifiers are MUCH more efficient and run MUCH cooler than their analog counterparts. (As a side benefit, they're A LOT lighter too )

Here's a good write up on why digital amplifiers are much cooler: http://www.audioholics.com/audio-amp...dio-amplifiers

Secondly, the location we picked is actually better for air flow than the stock amplifier location for 1 main reason. There's actually an opportunity for some great airflow there "under the carpet". There are 2 vents on either side of the trunk of the roadster that vent into the well behind the quarter panels. I assume the factory has these for when you slam your trunk shut. The thing is... THEY ARE HUGE!! (top of the 2nd pic below) So you can rely on either convection to let excess heat out, or should I experience some problems, it'd be truly trivial to throw a small 12v $40 computer fan that's switched on/off with the amp itself.

Check it out. You can see the huge cavity that flows under the cross member next to the amp (top of both pics below). We routed wires into it. you can see the large wheel well vent just on the other side of the cavity. (In fact, if one wanted to add an audio processor, that would be a great place to do so)





- - - Updated - - -



I WISH i had good fab abilities. I'm an electronics guy I had the small panel and sub enclosure fab work done by a highly reputed local shop. HandCrafted Car Audio They're very reasonable for the quality of work they do (read not-cheap, but not insane), super straight forward and are willing to prioritize what's important to you (OEM+ appearance in my case). I have no connection with them other than being a VERY satisfied first-time customer.

The sound is LIGHTYEARS ahead of the stock harman kardon system, but let's be realistic... it's a roadster The sub hits CLEAN. It's not "boomy" or anything. Honestly, it just sounds like deep bass but you can't really tell it's coming from a sub. Which... IMO is just right.

Nice! I know the Fs is limited with the smaller enclosure, but was hoping for at least a little more thump than the 6 1/2" Kicker. And yes, the perfect tune leaves the sub unable to be localized, just a nice fill of the lower freq's. Just as an FYI, I found the best blend with the sub polarity reversed, and that is also the way that the HK sub was originally wired. And, LOL, I agree. With the roadster, it is easy to reach the point of diminishing returns, especially at 70 mph with the top down.

I went with class G/H amps because of the low heat output/high efficiency, as well as having a class A/B output stage. I have a 250w bridged mono amp on the left-hand bracket for the sub and an 80w x 4 amp on the right-hand bracket driving the mid's and tweet's separately with a head-unit that has built-in active crossovers. Has been in place for two years now and haven't had a thermal shutdown yet. If I needed to, I was planning to do what you saw, mount some computer muffin fans right over the vent flaps blowing outward.

If you decide to do that, I would suggest instead of driving everything directly with your amp turn-on lead, run the amp turn-on to a relay and use that to kick on the amp/processor/fans. It would suck to kill the output transistor on your head-unit amp turn-on by hanging too much off of it. The general rule-of-thumb that I've seen is to directly drive NO MORE than two devices from the head unit in terms of the turn-on lead.

[esses]

Nice! I know the Fs is limited with the smaller enclosure, but was hoping for at least a little more thump than the 6 1/2" Kicker. And yes, the perfect tune leaves the sub unable to be localized, just a nice fill of the lower freq's. Just as an FYI, I found the best blend with the sub polarity reversed, and that is also the way that the HK sub was originally wired. And, LOL, I agree. With the roadster, it is easy to reach the point of diminishing returns, especially at 70 mph with the top down.

I went with class G/H amps because of the low heat output/high efficiency, as well as having a class A/B output stage. I have a 250w bridged mono amp on the left-hand bracket for the sub and an 80w x 4 amp on the right-hand bracket driving the mid's and tweet's separately with a head-unit that has built-in active crossovers. Has been in place for two years now and haven't had a thermal shutdown yet. If I needed to, I was planning to do what you saw, mount some computer muffin fans right over the vent flaps blowing outward.

If you decide to do that, I would suggest instead of driving everything directly with your amp turn-on lead, run the amp turn-on to a relay and use that to kick on the amp/processor/fans. It would suck to kill the output transistor on your head-unit amp turn-on by hanging too much off of it. The general rule-of-thumb that I've seen is to directly drive NO MORE than two devices from the head unit in terms of the turn-on lead.

Totally hear you. My sub's wired with reverse polarity as well. I think being in Phoenix AZ .... in the summer right now... I'm about to put my theory through some serious paces. We'll see if I need to add the fan or not. And yes... very very good point on using a relay. It's also a nice cheap way to isolate expensive electronics from what's bound to be a very electrically noisy fan motor