Astral

My first audio install was in my previous (and first) car, a Mazda Protege. The install started out ghetto and grew into something halfway decent towards the end. Much was learned. One of the things learned was: plan first. Second thing: don't buy component speakers without listening to them first.

I made this planning page to plan out the speakers, amps, and all the installation issues. I list all the things that I have determined and all the things that are still unclear and need resolution. As I resolve things, I hopefully can figure out all the installation hardware and wiring that I need.

For front speakers, I liked the Boston Acoustics SL60 6.5" components. Great sound for the price, and I may just end up going with them as a 'starter set', and upgrade to a beefier/better set later (or go DIY components).

For the sub, I have a 10" sub that I've been really happy with. It plays really clean in a sealed box, hitting really low (for a sealed sub) in small boxes. I currently have it in a .75cuft box, and it will be transplanted into a .8cuft 4080 box. Hoffman's Iron Law, though, dictates that you pay for low end in a small box with low efficiency. It's rated for 500W RMS, but only gets as loud as a JL 10W6v2 with 250W RMS (at 65hz). It's a SVC 4ohm sub.

This limits my amp choices. Most monoblock Class D amps are designed for high output at 2ohm or 1ohm. So to get 400-500W RMS at 4ohm in one channel, I need to look for super-beefy 1000W RMS x 1ohm type of amps.

It seems to make sense to try a 2-channel Class AB amp, so that bridged I can extract maximum power at 4ohms in one channel. So I am also considering that option, although class AB isn't as efficient as class D (but do I really need to worry about efficiency?)

What further limits my amp choices is space. I don't want to use the drop hole in the middle of the trunk (I really like it for groceries and misc stuff), so I'd like to mount the amps as much out of the way as I can. Right now, it looks like mounting the amps on the seatbacks (one amp per each) is the best I can do. That limits their size to about 13.75" x 11" (guesstimate based on a photo)... I still need to measure to be exactly sure.

The wheel well sides are also an option, but that's even tighter.. only about 13"x12" of space to play with. I am wondering whether I am missing out on some other creative amp mounting options?

For the front speakers, I already acquired the amp: bought a used JL Audio 300/4 for $250. It will power the front speakers at 150W each. Overkill for the SL60s, but that just means that I won't turn it up as much.

I am still undecided about the amp ground situation. There are members strongly suggesting to run the ground wire all the way back to the battery, but it seems like a few people have had good results with grounding things in the trunk. I haven't done any resistance measurements myself yet, and I haven't seen any such measurements from anyone else.

The other major undecided thing is how to wire to the stock base (non-Bose) radio, but I'm making some good headway there. It seems that all I need is a radio harness & a reverse harness to cleanly tap into the stock signal outputs. The harnesses appear to be identical to those that I worked with on my Mazda Protege, but there's a lot more pins used this time (4 to 6 more it seems). I don't want to lose steering wheel controls or any stock headunit functionality. I just ordered two Best Kits reverse harnesses (supposedly same as Metra 71-7903), so that I can relocate any additional pins from one harness onto the other.

It's tempting to reuse the existing rear speaker wiring to get the signal for the sub (I'd be disconnecting the rear speakers), so that I'd only really have to tap into the front speaker outputs from the head unit (to run those wires all the way to the trunk). Of course, the negative there is that the stock rear speaker wiring is weaker gauge (and possibly noisier) than wire that I may run, but it'd only be used to power the sub anyway.

So, amp mounting position, how to run ground, and how to tap into stock radio are my primary unresolved issues. They are detailed more (and in a more organized fashion) on my planning page.

Any feedback, comments, insights, etc welcome!

lurch519

ok, amp wiring, use 0 guage, as the current draw you are going to see is going to be in the neighborhood of 100 amps or so, and the length requires that guage. run ground all the way back to the battery, as it seems you are worried about how clean the sound is, and that will help with quality.

as for front speakers, i am not sure what to reccomend size wise as i dont know what is in the non bose system. i have the bose system in mine, and i am planning on doing the diamond d9 component system. very impressive speakers, and they are bi ampable. you can put 75 watts to each mid and tweet. the mids are 7 inch. here is a link to the manual

http://www.diamondaudio.com/products...formation2.pdf

as to the reverse harnesses, those should work.

i have yet to start any of the installation in my 8, as i am still planning my install as well. i do work in a car stereo shop, and have access to many products, supplies, and tech help. anything i can do to help, let me know.

Astral

front speakers, it seems like you can fit anything from 6.5" to 9" components, as long as they are under 3.1" deep. so 8" or 7" components will fit. those are hard to find, though. 6.5" should work OK (I may have to muck w/ the sailpod to install the tweeter). Diamond D9 looks like a good option. I need to go listen to them first, though (will take a day off work one day and go listening to speakers).

thanks for the feedback so far!

lurch519

if you decide to get the diamond's, let me know. i am an authorized dealer. msrp on them is 1100. i can get you a much better price. plus the crossovers have a feature called RAF. stands for rear acoustic fill. you can piggy back another set of speakers on them for rear fill, so you dont have to lose the 6x9's in the rear, and you wont have to use another amp either.

Astral

The RX-8 seatbacks. Looks like there's plastic covering them. What is behind that? Is there a bunch of sheetmetal? Just wondering what could be used to secure amps to that... probably drilling into plastic is not a good idea (i.e. won't hold).

lurch519

i havent really looked at amp mounting as of yet. one thing you might be able to do, is if you have the spare tire, take the spare tire out, and build amp racks to mount to the spare tire mount. that keeps em up off the floor and seat back, and should still leave you plenty of room for gorceries.

Tamas

iTrader: (1)

If you're removing the rear speakers anyway, maybe you'd have space to mount the amp underneath the rear shelf where the Bose amp is. Although that's a rather narrow area, so maybe just an amp with elongated shape would fit.

Astral

Ah, that's an interesting proposition. I wonder how stable I could get such a rack to be.

forbidden

Find yourself some small chassis amps like the newer Concept HC series.
A good 2 channel amp bridged mono is going to be great for that single sub. They will also lend themself to being mounted up under the rear deck. Make an aluminum drop panel, upholster the bottom side and mount the amps on top op of it. Do run the ground wire up to the battery. I will not be on the forum much for the next couple of weeks due to lser eye surgery, kinda making things hard to see but hit me up by e=mial to forbidden@telus.net if you need any further help.

Davey's RX-8

iTrader: (1)

My system is already installed. For those who want pictures, it may be a while. Some clown stole my digital camera a couple months ago, and I'm in no hurry to replace it.

Here is the hardware:

Head unit: Kenwood KDC-x869
Front speakers: Boston Acoustics Pro 6.5.3
Rear speakers: Boston Acoustics Pro 6.5
Subwoofers: (2) Boston Acoustics Pro 12.5 in a sealed box.
Main Amp: JL 450/4
Sub Amp: JL 1000/1
Sirius Satellite
iPod hookup
HD radio tuner
Power distribution: Yellow top Optima Battery, D35 series, 15 farad Alumapro Capacitor
RCAs: 4 channel 5 meter set of Monster Cable XLN Pro for the main amp and a 2 channel 5 meter set of the same Monster XLN Pro for the sub amp.
Speaker and power cable are all Monster but are pretty generic in the regard. I COULD have shelled out huge money for the high end Monster speaker cable but decided it wasn't going to offer a noticeable improvement. Power cable is power cable.

continued....

Davey's RX-8

iTrader: (1)

Here's how it was done: (FREE UNABASHED PLUG TO MIKE REID AT TWEETER ETC. IN DEDHAM, MA FOR THE INSTALL)

We started with the front speakers. Since I had the Blose system, we had a 9 inch woofer in the doors. That made it EASY to fit both the 6 and 4 inch woofers of my three way component system in there, and the crossovers are also in the doors. Those things are huge.

The rears were also easy as it was mostly drop in.

I have had the same subwoofer setup with the Bostons for about five years now. Since we couldn't get the box in through the trunk, we pulled out the rear seats and removed the metal support bars. Then we slid the box in through the back seat. It is bolted down and pretty much fills the entire space underneath the rear deck. By the way, the Bose amp was yanked.

Moving on the amps, it was clear there was no natural mounting spot in the trunk for both amps together. Both amps are identical in size would each take up the recess on the trunk floor. So what was done was to create a false floor on both sides of the amps so that it looks like they fit naturally. They face front, and one lies slightly on top of the other with a bit of a tilted upwards look.

Next to the sub, we put my sirius tuner as there was no other place. Since it would then look like crap, we created a back panel to hide the sub and all other electronics in there. The way Kenwood works, most of their accessories plug in through the cd changer port. There is a three device maximum so I had to be careful about what I hooked up. I decided to make the iPod the last item in the chain as it had to be an end link if it were installed. A small hole was drilled in the center console under the arm rest, and the connector for the iPod sticks through there. Not very decorative, but also very stealthy and a prospective thief wouldn't know it was there.

continued....

Davey's RX-8

iTrader: (1)

As far as the electrical stuff goes, the cap was mounted on the back of the sub box facing the rear seats. The capacitor is a one inch high rectangular box and not a cylinder like many caps. The Optima battery was an easy install, but I have yet to figure out a way to get Monsters competition battery clamps to connect to the positive terminal and the factory fuses.

As far as the back panel and floors in the trunk go, they were covered in the same dark charcoal like color material as the trunk was. I then ordered an RX-8 logo from Rosenthal Nissan (as part of another order) and slapped the logo on the back panel. It looks sweet.

So what else......? Oh yeah, the head unit. Bet you're all wondering how that worked out. Well I bought a top dash 1 din fabricated part from ScudRunner. I simply put the radio on top of the dash and ran everything from there. I was lucky enough (or wise enough) to not have gotten the factory navigation system.

Questions, feel free to ask.

Astral

Thanks for all the info so far!

I just 2 BHO7902 reverse radio harnesses, and they only have two small pins in the top two rows. (See this link... the rows that start with E and H pins) The harness only comes with pins in H and R positions. I determined that I need 2 more pin sockets (I can transplant two extra off the other harness).

Is there anywhere that I can buy these small pin sockets, short of ordering another reverse harness? Is this a standard item of any kind?

Astral

An update on my audio system. I have most of my parts ordered. Decided to go with Alpine MRD-M1005 (almost definitely a seatback mount) amp. Pretty much all the components are set, with the exception of the front speakers (I am still listening and trying to figure out how to blow the money).

I ordered another reverse harness and three normal (into car) harnesses (not taking any chances here). I haven't heard back on that order, so I am afraid that it may not come in time for this weekend (when I hoped to install everything). No harnesses == no front speakers.

One area of concern became the size of the crossovers. One of the sets I'm looking at is the Boston Acoustics Pro60, but the crossovers seem to be just big enough to barely fit. I hope they fit, because I liked those speakers. I took off the passenger size door tonight to take some pictures of the available space.

Anyways, this is a pretty worthless update .

lurch519

how much did you spend on the mrd, and how much did you pay for the harnesses. i dont keep the reverse harnesses in stock, but i should have the regular 7902's in stock, and i could send em out via usps priority mail and have em to you by sat, even if they go out tomorrow.

Astral

I spent $327 on the MRD-M1005 (grey market), and harnesses were like $8 each. The reverse harnesses are impossible to find in stock (I tried back in 2003). The normal harnesses (Metra 70-7903) I can find in a local BestBuy easily, so I can get those anytime (just a little more expensive in a B&M store0. So don't worry about it, I do appreciate your concern, tough.

lurch519

good price on the mrd, but just to warn you ( i am assuming you got it online), no warranty. period.

Tamas

iTrader: (1)

No warranty is really a rare problem... not saying it doesn't happen, but I won't lose any sleep due to the fact that my Alpine amp is also an online buy with no warranty.
These things are pretty reliable. Even my installer at the audio shop told me to buy online because the risk is little if the component is brand new. I saved 40% on my amp's price.

Astral

yep. figured alpine amps should be rock-solid. the price difference was indeed way big between that and shop. so *crosses fingers* (i just jinxed myself)

Astral

OK, contemplating a possible rear deck mount... just took this pic with some basic measurements:



The idea is to mount the JL 300/4 amp (which is ~ 13.5" x 9" dimensions).

I did a little test sizing today in that space. The amp barely fits in that space (that space is as wide as the amp, a little over 9"), and the 13.5" width puts it between the rear speakers (which are 14"). I would need to lower the amp a little past the recessed area, so that I could actually access the controls.

In that photo (pardon the total ghettoness), the white lines are just dimensions. The green rectangle is about how large the amp will be in that space.

My challenge there, it seems, is how to secure the amp board w/ the amp on it to that rear deck.

The idea is to mount the amp upside down, so bottom-to-top: amp (screwed on to the rack), amp rack (somehow attached to the rear deck), rear deck.

You can see that there are 4 bolts sticking out of the rear deck (7.125" apart in the X coord, 6.25" in the Y). These bolts are used to hold the Bose amp in the Bose stereo systems. In my base radio car, they simply hold a cover.

I can get access to that rear deck from the top, so I imagine that I should be able to screw and unscrew these bolts from the top.

I wonder whether I can get some sort of nuts that I could "counter-sink" into the plywood... and then screw those bolts into those nuts... Not really sure whether 1/2" plywood would be sturdy enough there (I have some 1/2" birch plywood now), but I could go and get thicker plywood.

It seems like I couldn't have anything sticking out of plywood on the other side, as that would interfere with screwing the amp down onto the wood.

Hmmm....

Tamas

iTrader: (1)

IMO that location would be much better than attaching the amp to the seatback. If you have enough space, go for it - the idea with the plywood board is a good one.

Astral

OK, so the update on my car audio system. For the time being, I decided to just put my amps on the floor behind the rear seatbacks. Neither fit on the seatbacks, but I did put the LOC, and the ground distro and power distro blocks on the left seatback.

Before the winter started, I installed the Focal 165KFs in the front doors. I installed the Elemental Designs e10o in the 4080 box, and later I switched to the Dayton Reference Series HF 10" sub.

So I made a couple of major mistakes:

* I flushmounted the tweeters to the sail pods by the A-pillars. Kills the soundstage, sends it to the floor. Don't do this, unless you have some omnidirectional-type of tweeters. This aiming sucked. It would've been much better to surface-mount the tweets. I was recently able to reaim them much better, by playing with the bracket that holds down the flushmount tweet, but I need to get new sail panels and surface-mount the suckers.

* My right speaker was out of phase (*egg on face!*... more like omelet on face)... I don't know where I made the mistake.. I'm going to take off the doors and trace every wire. For now, I switched the polarity at the amp.

So for a while (before I fixed the phase issue), I was wondering where all the bass was... I was quite disappointed, in fact, with the Focals, as they were touted to have monsta bass.

The Dayton RS HF 10 sub is a nice sub. It goes pretty deep and hits loud-enough with only 350W RMS. It goes lower than my e10o did (as measured near-field outside), so the e10o must've been out of spec or something, because the reverse was supposed to be the case. *shrugs* Could be just my measurements too.

Astral

Ok, so, some totally random ramblings about my car audio tunage, or fun with a real-time frequency analyzer (RTA):

* Focal 165KF's installed in doors, fed by JL Audio 300/4
* Dayton Reference Series RSS265HF-4 10" sub, fed by Alpine MRD-M1005
* Eclipse EQ2102 on the whole input signal path

So I recently got that 30-band 1/3rd octave Eclipse EQ2102 unit, aiming to go and conquer the insane cabin gain transfer function of my RX-8 (and all others, I suspect). I also wanted to take off some of the harshness in the midrange and otherwise tune and see what I can get.

All graphs smoothed to 1/6th octave unless noted otherwise. Measurements taken with the mic taped to the driver's side seat at my right ear's level.

Moron, it's out of phase

No pics of this, but it went something like this:

* Measure left speaker freq response.
* Measure right speaker freq response.
* Measure both on.
* WTF is my bass quieter with two speakers?

Out of phase. Change phase on one speaker.

* Measure both now. Oh my -- I have bass now!

Left vs right speaker: sealed vs not-as-sealed

So I measured the left speaker (orange line) and then the right speaker (blue line):



What do we see here?

Ah-ha, when I did the initial install and was wondering why there was no bass, I thought that maybe I poorly sealed my speakers. So I went to the right door and sealed up the space around the speaker mounting hole. I think I had little gaps left on the left side. However, I didn't hear any difference (with speakers out of phase, and not broken in, and highpass set too high), and so I said, well, this sucks and left the left door alone.

Now, we can see that the better-sealed speaker has more, louder bass and the speaker w/ some gaps has quite a bump around 180-450hz, probably caused due to some port-like effect from the gaps (my guess).

Well, ****, I'm going back and sealing up the left door better tomorrow (I found this out yesterday, but today I had to be at work until 8 and so I couldn't make it back in time for daylight).

Ok.. so I can solve the low midrange hump later, let's move on to measuring the full system.

Full system initial tune

This RTA chart shows:

* blue line: full-range output from front speakers, no EQ or crossovers
* orange line: fronts high-passed at ~50hz, 24db/octave, no EQ
* green line: fronts high-passed at ~50hz, 24db/octave, -4db reduction via EQ on ~3.5khz and up, a tad added at 500hz/630hz and a tad removed at 80hz.



So, what do we see from here?

First of all, holy ****, do these speakers have mad bass. Bass down to 50hz! I was impressed.

Second of all, my A-pillar tweeters are too loud. I have the crossover set at -3db, but I need to change it to -6db, as you can clearly see a step-up in response at around 3.5KHz (crossover point is 3.8KHz). The system sounded too bright. Until I turn down the tweets, for now I lowered the high-frequency response, which is what you see reflected in the green line.

Third of all, wtf is that hump around 800hz to 1.6khz? Dunno, I will have to move the mic around the driver's seat and take averages of all the different locations, to compensate for inevitable phasing issues.

(BTW, for those of you who have seen my poorly-aimed tweets, they are aimed much better now [although not as nicely as they could be]).

Fourth of all, that 50hz highpass does quite a mean number on the frequencies above 50. Look at how much 60-80hz is hurting after the highpass is engaged.

Insane cabin gain/transfer function

Subwoofer tuning adventures. These are sweeps from 20hz to 200hz, with the sharp falloff masked a little by the 1/12th octave smoothing on all of these curves. The sub was lowpass at 200hz, 12db/oct.

* green line: trunk closed, subwoofer aiming into the side of the trunk (normal location, permanent for this enclosure)
* yellow line: trunk closed, subwoofer aiming into the front of the car from the middle
* orange line: trunk closed, subwoofer close to the trunk lid, firing into the back at about 70 degree angle to the trunk (so kinda perpendicular to the back of the trunk, but not quite.. this is because I didn't have enough wire length at that moment to aim it straight into the back at 90deg)
* purple line: trunk opened, subwoofer aiming into the side of the trunk



Couple of interesting observations:

* Below 65-70Hz, the bass response is essentially unchanged despite the different orientations of the subwoofer. This is probably because the wavelengths are too long to for the reflections to really cancel inside the trunk at those frequencies (and my trunk is small). If you look at this page, you'll notice there's a lot less less difference between front/rear aim at 60hz and less for smaller trunks (the VW Beetle) and a lot more for bigger trunks/spaces (the Tahoe). In my measurements, the orientation mostly changes bass above 80hz, where the front-firing configuration fares the worst and the rear-firing the best.

* Anyways, that's good because this means that my side aiming (in my car) isn't: 1) messing with frequencies I care about much, 2) is not the one introducing the giant-*** hump in the cabin gain.

* With the trunk opened, there goes my deep bass! Cabin gain is almost gone and you can see a relatively-smooth fall off in the sub response (it was even smoother when I did a near-field measurement outdoors).

But most importantly, the difference between purple line and the green line is essentially my car's cabin gain/transfer function:

* Holy ****, is that some insanely uneven cabin gain! Look at that 12db gain (4 times the volume!!) between 40hz and 65hz. WTF is causing this in my trunk? I wondering whether the deadening will help this.

* On the other hand, you could probably take a tiny-*** sub and take advantage of this transfer function by having it fall off by 65hz... the transfer function would pick that up and carry the bass deeper, and you could use a have small sealed efficient speaker, and most people would be happy.

I tried taking care of this hump with my EQ and it required something like -12db cut at 50hz to tame. Daymn. This is gonna make things tricky.

Trying to get my sealed box sub to go low

So now that my fronts go down quite well to 60Hz, why should I have the sub play anything above that? I shouldn't...

So off I went, trying to see how much I can lowpass my sub and have it effectively extend me some bass response.

1/12th smoothing on sub lines, 1/6th smoothing on the full-range line.

* purple line: sub lowpass at 60hz, all are 12db/oct
* yellow line: sub lowpass at 53hz
* orange line: sub lowpass at 45hz
* blue line: sub lowpass at 45hz, playing together with the fronts highpassed at 50hz 24db/oct



So this trunk cabin gain hump is making my life hard. I need the sub to evenly, but the big hump really gets in the way at 50hz and threatens to make things too loud there.

So I start trying to tame it by lowering the lowpass frequency. As you can see, at 45hz, the 35hz and below frequencies aren't affected all that much, 35-40hz is a little hurting, but the 50hz hump stepped off in a big way.

Now, the challenge is try to tame the 50hz some more and get a little more low-frequency action from the sub.

I considered stepping down the lowpass frequency even lower (below 45hz), but haven't had the time to try last night. Will try again later.

EQ'ing me some low low bass (or trying to)

* blue line: unEQ'd sub (lowpass at 45hz 12db/oct) and fronts (highpass at 50hz 24db/oct), same as blue line from graph above
* purple line: a bunch of EQing on the sub area, Eclipse EQ and amp sub gain



Dial down 50hz a little on the Eclipse EQ unit and dial up 40hz and 31.5-something hz (may not be 100% correct at the moment about the frequencies). This brought back some bass there, but not enough.

So I dialed up the (OMG, i know... sinful) the bass gain on the sub amp to +4db, which is centered at 45hz.

The combination of that gave me a bunch more bass at 30-40hz (of course, how loud will that bass get with the sub's excursion capabilities is another question), and seemed to smooth out my response some.

So here I am as of today. Still major peaks/valleys in the sub response. Hoping to fix the nasty 180-450hz hump by sealing properly the left speaker, and then we'll see what the Eclipse EQ can get me.

I will say this.. right now the bass sounds substantially better than it ever did on my speakers. It is substantially smoother/more integrated, and, heck, deeper too. The only problem is some missing high bass at that 150-200hz valley, I will have to go examine that later, but overall, so far so good

I never thought I'd be lowpassing a sub at 45hz...