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Discussion Starter #1
W220 (2004 Comand NTG1 MOST optical) Sound System Upgrade – my journey

Owning 2 Volvo S80s, a later one with Dynaudio Dolby PLII, I was keen to improve the sound to at least match the Volvo.

These improvements happened over about 3 years. Before each change, I would compare it with the cars I own as well as other cars I would rent when I travel. Where available, I would opt for a premium or luxury model, just for sound system evaluation and comparison.

My main criteria when performing these upgrades was not cost but that everything had to look stock and reversible. This meant not cutting out any panels/ grills, no protrusions, etc.
 

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1 – Upgrading tweeter.

I though this was the only upgrade I would do. I put JBL’s in and there was not much of an improvement. After only a couple of days, I removed it and put the old ones back. The lesson learned in this stage gave me the confidence in removing the door panels as well as researching in car audio brands beyond the run of the mill (JBL, Sony, Pioneer, etc)
 

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2 – Changing main door speakers – Focal 165 KR2 Component

From the fairly flat frequency response charts and good reviews, I thought this would be the one! The 6 inch drivers had huge heavy magnets on it and are well built, certainly much better than the Bose. There was a definite improvement. I had the Focals installed for nearly a year before I decided I need tweeters that delivered more at the high frequency. The problem may be, in part, me not wanting to cut out the existing grill, so the tweeter sat deeper about 2/3 of an inch from where the original tweeters would have been. The vocals and mid range on the Focals are very good.

Also added was butyl and sponge damping directly behind speaker enclosures on bare metal of the outer door panel.



On the speaker enclosure of the first door has vented louvres. The bottom vent on the front enclosure is not covered and water gets in. It was only raining a little when I did this upgrade and I was surprise to see bottom part of the front speakers a little wet. I found a evidence of well established watermarks, so I block the bottom with butyl and create a mini dam to isolate water from the speaker edge. Water and MDF spacers don’t mix. The rear door enclosure don't seem to have this problem but they have less space/volume. Speakers fitting the front may not necessarily fit the back, even with spacers.
 

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Discussion Starter #4
4 – Coax & ribbon tweeter – Hertz HCX 165 + Hertz HT20R

2 way speakers kit 165 KR2 - Focal Car Audio drivers
http://www.hertzaudiovideo.com/wp-content/uploads/2014/05/Hertz_HiEnergy_HCX165.pdf
http://www.newaudio.it/hertz/htr30r/ht20rrr (2).pdf

I replaced the Focal components with a coax and tweeter in order to convert a 2 way system to a pseudo 3 way. The coax sounds surprisingly good even without the additional tweeter. The HCX 165 construction was very good and I like that the angled center tweeter which could be rotated to improve off-axis frequency response. I like the transparent sound of ribbon tweeters but it sounds quite soft. I later found out that the frequency response of the ribbon was 6Khz – 40Khz but the supplied crossover limits it to 10Khz – 40Khz. Since there is not much volume beyond 10Khz, it sounded soft. I then removed the crossover and it sounded louder. I add a capacitor as a simple DIY solution for a 1st order high pass filter rolling at just under 6Khz. This combination was an improvement and was in place for nearly a year.

Capacitor values for protection 1st order high pass filter is calculated here, the inductor is not required for 1st order unless you want a crossover.
Passive Crossover Slopes
 

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Discussion Starter #5 (Edited)
5 - Coax & tweeter – DLS226c & Hertz HT20

I read good reviews on the DLS so I decided to replace the Hertz HCX 165. Due to size and availability I settled for the 226 which is actually more of an entry level range (when compared to the Focal K series and Hertz H series). I managed to source then at a good price from an ebay seller based in Bulgaria and I can confirm the product was definitely authentic. The construction was lighter than Hertz/Focal and was surprised at the improvement. Spacers were no longer necessary in front and only thinner ones for the back. There is more bass and sounds more neutral.

I had the HT20R for nearly a year before I decided they were just a little too soft, I installed the HT20 instead.

http://dls.se/en/car/prod.html?produkt=en_920

HT 20 - HertzAudioVideo car audio system
 

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Discussion Starter #6
6 – Center channel upgrade – Focal TNK

I was oblivious to the existence of this channel until numerous upgrades created an obvious hole in the center. The existing center channel speaker is only a mid-range driver and will lack good high frequency reproduction. Removing the existing speaker would involve the removal of the entire dashboard and that was going to be hard. I tried squeezing my hands through the small hole in the center behind the air vents above the hazard light switch. Behind this vent, there is a steel bar that obstructs the majority of the hole, spreaders won’t work and I risked breaking something. It took a week of on and off thinking before I came across a better solution that did not involve removing the dashboard.

I decided against installing a replacement speaker in the current center position because I thought passing good sound through the little square grill with tiny pin size holes was going to deteriorate the sound considerably. So I thought I’d place an additional tweeter in the small cavity where the front middle top air vent is. I had to file away a little one of the removable vent from the inside that can't be seen from outside. This vent directs some air front the front to the back. Putting the tweeters here blocks about 2/3 of the air. I don't expect this to affect rear seat air-condtioning too much as there is already a vent behind the center console, B-Pillars and floor.



Looks OK installed. Sounds good too.



I bought a used speaker from ebay just for the connector and used it to connect to the new Focal TNK tweeter. Then in series connected it the existing speaker (via scotch lock), this way I now have both a good tweeter and the existing mid-range driver. The additional connector really was not necessary as you could tap into the existing connector via scotch lock then connect to the new tweeter, what I did just made it easier to reverse the process.

The tweeters were much louder than the existing mid-range drivers. I made my own in-line attenuator called an L-Pad and experimented with several to bring it in line with existing mid-range driver.

The required resistor values can be calculated here depending on the impedance and desired attenuation.
L-PADS

I started with 10watt resistors because that was what I saw in the Focal crossover boxes, but really, 3watt is plenty. I bought many of these metal resistors on ebay cheap. Pre-packaged sets of various values are available. I bought 0.1ohm to 47ohm. I did not require anything outside these values. Initially I started with mini circuit boards, but just a simple connector with wire, soldered, then properly isolated with electrical tape is good enough.



View behind the vent, sticky foam added to limit rattles. You can also see my DIY L-pad and Capacitor (1st order high pass filter)

Since the Hertz HT20 sounded so nice on the doors, I later replaced the Focal TNK with Hertz HT20 on the center. I did this for about a week, then decided that the center actually sounded better using my initial Focal TNK and reverted back. Although, Hertz had good high frequency, vocals just sounded better with the TNK.

Of the 6 steps so far, this is the cheapest yet the biggest leap in sound quality.
 

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Discussion Starter #7
7 – Subwoofer location / mid range – Hertz DCX87.3

Some of the Bose subs (not all) are equipped with 2x 3” mid range drivers. I opted to replace the mid range with mid - high frequency coax Hertz DCX87.3 (spec @ 130Hz – 21Khz, this probably rolls off much sooner).

This is mostly ambient sound and makes a bigger difference for rear seat passengers, much less so for front seat passengers who are seated further away. This install was easy, like plug and play, no removal of the subwoofer assembly required. Non – essential, but the DCX87 was an easy and inexpensive upgrade.

I did remove the subwoofer assembly (painful) to examine the enclosure but could not find a suitable alternative sub driver that did not protrude into the trunk/boot space. So I left the main sub driver unchanged.

DCX 87.3 - HertzAudioVideo car audio system
 

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Discussion Starter #8 (Edited)
8 – The game changer. Mobridge MA1000-DA1 / Alpine PXA-H800 / Focal FD 4.350

MOST Digital TOSLINK Pre-Amp | mObridge
Alpine Electronics of America, Inc.
FD 4.350 - Focal

I am aware some units out there like the Audison could take amplified signals, step it down, process that and then re-amplify, but I felt doing this meant the sound was not lossless nor clean. Although I have been aware of the Mobridge since owning the W220, I knew more about their Bluetooth and Ipod interface products. The MA1000 did not come to my attention until I saw one on sale on ebay about a year ago. Then I researched into the other components and decided on the DA1 with Toslink out. The DA2 has analog RCA out for a processor with RCA inputs. The developers at Mobridge Australia was quite helpful answering all my questions and told me about the DA3 in development (now available). The DA3 has quite an advanced interface with built in EQ that would enable you to bypass a processors like Audison/Alpine, etc… and feed direct to power amp. This would suit someone who does not use the surround setting.
DA3 DSP Professional | mObridge

Since I had my heart set out on the Alpine PXA-H800, the DA1 was all I needed.

Before buying the Alpine and Focal amps, I bought the Mobridge. then ordered a cheap Optical Toslink to analog adaptor with headphone jack from Aliexpress. I wanted to make sure the Mobridge interfaced with the MOST optical system before spending more money. It worked flawlessly. Navigation vocals cuts in OK, volume control works from HU, steering wheel, etc. Being Toslink, fader will of course be controlled after the optical signal.

I spent nearly a week (or 2) reading some 100+ pages of posts about the Alpine from DIYMOBILE
Alpine PXA-H800 Processor Discussion Thread - Car Audio | DiyMobileAudio.com | Car Stereo Forum
I looked for alternatives, eg Audison Bit One, JBL MS-8, Rockford Fosgate 3sixty3, and more

I wanted a compact processor with features additional ambient sound, the Alpine PXA-H800 was it. You could select from regular Stereo, Dolby Pro-Logic 2, Euphony (proprietary surround option) and Rear Fill. Within Euphony itself, there are preset surround settings, Acoustic, Live, Cinema, etc.. as well as your very own custom settings so you could vary the ambience and the level for 3 sets of channels. If that is not enough the PXA-H800 is also equipped with MX (Media Expander) Plus setting (on/off).

The PXA-H800 also features Road EQ something I was keen to try.
http://www.alpine.com/e/research/alpinesoundexclusive/roadeq.html

For me the Class D Focal FD 4.35 was the obvious choice, compact enough to fit into the existing cavity, stay hidden and the low heat from efficiency of Class D amplifiers. The Alpine RUX even features a gauge to monitor ambient temperature.

Identifying the pinouts was simpler than expected, the speaker out had colored wires that were unique and corresponded to the colors on the door panel. I connected the supplied forked spade on the amp end and a 2.8mm spade directly into the female socket connector that I unplugged from the amp. Butyl came in handy again to limit movement, reinforced with duct tape.

I routed the mic to the rear parcel shelf area (I might change this later) and the USB cable (for laptop connection) and RUX cable via a small gap behind the back seat (without actually removing the back seat) just above the corner of the fuel tank, I manage to do this by just removing the panel next to the door sill. Currently the cables and RUX are out of sight underneath the passenger front seat.

These units all have 12v remote trigger switches that automatically turn themselves off.

When the Alpine was powered for the first time, the defeat was set to max, I had to use the RUX to turn the volume up.

When I listened to the new amps and processors for the first time, I was amazed at the sound, this is even before tinkering with the EQ or any surround settings. There were probably some EQ happening with the stock setup, but if there was any, I did not think it was drastic. The improvement I believe was owed to mostly the processor and the new amps. I remember being mesmerized, listening to all my favorite tracks for the whole day with a flat EQ.

The fun really began with the EQ adjustment. With a few initial EQ adjustments it sounded even better. EQ is very important as Skylaw and some others have pointed out. I enjoyed this process of tuning far more than speaker installation and opening door panels. There is a fixed 31 band graphic EQ (simple) or a more complex 10 band parametric EQ (with lateral adjustments in 1/6 octave increments). Even the subwoofer channel has a 10 band EQ which makes extending the bottom end possible. You can adjust each channel separately or in pairs. The unit does come with a small microphone for RoadEQ. I decided to use a proper measurement microphone and acquired a Superlux ECM999 and XLR Amp to USB from Aliexpress (mainly because I live outside the USA). Some may prefer the others like the Behringer, but any of these would be better than using a built in mic of a laptop or RTA analyser on a tablet.

The Alpine software installed and worked well on my Microsoft Surface Pro3 (Windows 8 64 bit). I use RoomEQWizard which has RTA, sine wave sweeps, waterfall, etc… In addition, I also confirm measurements using a tone generator with SPL meter and manually plot my readings on paper. Based on the mixed review of the automatic feature ImprintEQ, I have decided against using this and opted manually adjust EQ. After each EQ, I would save settings on the laptop with notes as what I did, I can also recall previous settings to compare if one sounded better than the other. You can store as many settings on the laptop as the memory can handle, in additional it is also possible to store 6 quick easily retrievable settings.

The unit is very flexible, channel pairs or each individual channel can be muted for tuning. The x-overs have a very wide range and the unit even features a Time Correction for each speaker. I manage to achieve a sound stage using TCR but have decided against using it for the benefit of passengers.

Link for Room EQ Wizard, includes RTA analyzer and more (free with HT Shack signup)
http://www.roomeqwizard.com/

Here is a youtube link on setting up a XLR mic with an RTA Software on an Ipad using additional USB battery as a booster.
The USB battery was not necessary for my MS SurfacePro.

Link to suggested corrcetion values for RS Analog SPL Meter
http://forum.audiogon.com/cgi-bin/fr.pl?htech&983682086&openflup&1&4
 

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Discussion Starter #9
I have no training in electrical engineering or any car stereo installations, so this was a big learning experience for me and found it somewhat enjoyable.

My choices are based on my own personal preferences and the possibilities are of course not exhaustive.

I think my journey is now at an end, but I thought the same after step 2 and nearly every step after that.

So happy, am I now, with the stereo, I am thinking about what I can do to the Dynaudio on the Volvo.
 

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WOW! Thanks for that extensive writeup, poopbunny. That's quite a saga, and documents some very inventive approaches. I suspect this will draw a LOT of commentary and questions. It is now referenced in the Encyclopedia and in the Primer sticky in the Audio & Telematics forum.
 

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Discussion Starter #11
I add a capacitor as a simple DIY solution for a 1st order high pass filter rolling at just under 6Khz. This combination was an improvement and was in place for nearly a year.

Capacitor values for protection 1st order high pass filter is calculated here, the inductor is not required for 1st order unless you want a crossover.
Passive Crossover Slopes
Here is an updated / better link than above to calculate Capacitor values for High Pass filter depending on speaker impedance (ohm) and the frequency (Hz) where you want to cross.
Car Audio - Speaker Crossover Chart and Capacitance vs. Frequency Calculator(High-pass)
 

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Discussion Starter #12 (Edited)
Below is a pic of the EQ values from the Alpine PXA-H800
An attempt at a flat EQ - Starting point


Sine Sweep with 1/6 Octave Smoothing (Red curvy line), overlayed
RTA 1/6 Octave (Black blocky line)

Using Room EQ Wizard software and measurement microphones from previous posts.
Mic position about ear level above middle arm rest / console, pointing towards rear view mirror.

The Volvo Dynaudio frequency is not as flat but does sound a bit better. I might try to replicate some time and will post the RTA here later.
 
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