Acapulco Bill

Please check the condition of the subwoofer drivers under the rear seat, as it is common for the surrounds to get torn due to the huge excursions these cones perform.

The HK bass system receives it's own highly-equalized profile and signal from the Logic 7 processor in the headunit. This is transmitted via fiber optic to the Class D amp in the trunk. The two small woofers under the rear seat have a huge task, and although the amp has a high damping factor, the characteristics of the under-seat environment acting as the speaker enclosure unfortunately condemns the subwoofer to have an undamped, "fat" sound, IMO. Just replacing these subs with another brand will not change this fact.

Additionally, since the "advance" of audio quality has taken several giant steps backwards in recent years, with Pandora/Spotify, Bluetooth streaming, and recording MP3's on memory cards or USBs, there are some tips to obtain the maximum performance from the HK or any car audio system.
1.- Leave the tone controls flat. If you make adjustments, keep them small.
2.- Play only Apple Lossless tunes (preferably from a 6th Generation iPod Classic with superior DACs)
3.- If you must play MP3's, only 320k compression (which throws away 70% of the sonic information, and the bass suffers the most even at this bitrate). Many complain about poor bass performance when the problem is just using inferior formats such as MP3 or streaming.
4.- Under no circumstances should streaming sources be used to evaluate any sound system. Or MP3's for that matter!
Recommended for audition of any audio system are original AIWW CDs or downloading from iTunes in Apple Lossless format, which decompresses bit-for-bit to an original CD.

ap10046

Thank you again.
I will check the subs under the seat.
Although I do use 320K for MP3's on my SD card, what would you suggest please? I would prefer not to use CD's as burning them is an issue (no CD drive, and would need to buy an external drive and carry it around).

Also, a bit off-topic, but how does one get album artwork on an NTG4 via SD card?

Acapulco Bill

The absolute best sound quality, aside from an original CD, is a 6th Gen iPod Classic playing back Apple Lossless format into the Aux or old-style iPod connector. A 160GB iPod Classic will hold over 10,000 Apple Lossless tunes (this includes much orchestral music where the tracks are longer than more popular music, with more complex waveforms). If you purchased your music from iTunes, I understand downloading the Apple Lossless file is free. Also, make sure the Logic 7 ambient function is "off" when you audition, as the first thing surround systems do is turn crisp, clean bass into mud.

SD cards are fine for 320k, frankly I have no idea how to display album cover artwork. I understand that even with the SD card, the HK headunit decompresses and converts MP3 to analog, where some Logic 7 manipulation is performed if selected, then reconverted back to digital where more effects are available, split by a digital crossover, then sent to the digital amplifiers. I do not know if the door tweeters and woofers have separate amps, or a simple capacitor xover. In any case, the fiber optic feed to the subwoofer is so highly equalized that even with a Tousling input to an aftermarket sub, the sound would be unacceptable.

Some of my music is MP3 at the 320k bitrate, and I always immediately hear the difference, it's quite audible. My Millennial children, Bluetooth streaming addicts as they are, apparently don't mind inferior sound, although they certainly know the difference. The 762k MAXIMUM transfer bitrate of the current Bluetooth standard, irl does not get beyond half that. Too bad that the 21st Century trades "quality" for "convenience", and that goes also for politics, food, clothing and lifestyle.

Acapulco Bill

Really, for a few $ you can purchase a couple of preowned CDs of your favorite music, and use that as a reference for any other input source (of course with the Logic 7 Surround off). I always keep 6 CDs in the car's changer for when the iPod is being used in my home system.

ap10046

Lol.. That opened my eyes, alright!
All points noted.
I need to get the iPod aux for my car, it didn't come with it. I do, however have an iPod 6th gen.

Thanks very much for your extremely experienced insight and advice.

Acapulco Bill

Sometimes the regular Aux minijack in the glovebox is stuffed behind a large plastic triangular access panel, visible when the passenger door is opened. The downside is that no charging for the iPod is available. I have the iPod Integration Kit, which provides a 30-pin connector, and charges the iPod SOMETIMES. Frequently the iPod is given a bogus command from the steering wheel controls and freezes, requiring a reset of the iPod by depressing the center button and Menu at the same time. It's exasperating! Anyway it's a small price to pay for a quality audio source and 10,000 tunes.

An alternative would be to charge via the USB in the armrest, and run the Aux cable along the transmission housing. Unfortunately, our W204's don't even have one! A 2001 Toyota Corolla came with USB connectivity standard.

If you are going to load up your 6th Gen iPod, make playlists in iTunes first! Then you can choose a playlist to fit your mood/roadtrip and drive for hours without the distraction of selecting music while driving.

cbrea1418

you seem very knowledgable... any suggestions on new speakers or are those kappas still the best option>?

Acapulco Bill

There are many options. Here are some:
https://www.crutchfield.com/p_136990...50.html?tp=106
https://www.crutchfield.com/p_108K60...l?tp=106&avf=Y
https://www.crutchfield.com/p_091ISU...l?tp=106&avf=Y
https://www.crutchfield.com/p_109GTO...l?tp=106&avf=Y
https://www.crutchfield.com/p_091PS1...l?tp=106&avf=Y

One should avoid "brand bias" - for instance my son-in-laws' family owns JL Audio. But based on the specs (or lack thereof, since the first link has no Impedence spec), there are only two I would consider for the application of being driven by the Audio20 headunit internal amplifier, as the requirement is for high efficiency @ 93 dB/watt and low impedance @ 2 Ohms.

Candidates are the Infinity Kappa and the JBL Stadium. Both of these systems have a nominal impedance of 2.5 Ohms, the rest are 4 Ohms. In practical terms, these two systems will produce nearly double the SPL sound pressure level because of more available amplifier power vs. a 4 Ohm system. All the above links are 93 dB per 1 watt input efficient. Nearly all of the other choices on Crutchfield.com that fit the W204 are 90 dB efficient or less and 4 ohms or more, meaning there will be less than 25% of the sound output of the Infinity and JBL options. Both companies are owned by Harmon Kardon.

Best of success in your quest for the best sound possible with the Audio20 headunit!

cbrea1418

thank you. i have actually moved away from the stock to a sony xav-ax5000 sony unit and am considering switching that to something with wireless carplay in the near future. i've had the car since it was new and i am treating it like a "rich kid's honda civic," as i've heard it been called on youtube.

Acapulco Bill

Nice that the Sony XAV-AX5000 has a separate subwoofer output plus a rear camera input. Does it integrate well with the steering wheel buttons and the center console knob? Have been trying to integrate a backup camera to the Audio20 but my W204 is Eurospec and isn't compatible with U.S. video adaptors. Wattage-wise it's a bit low @ 17 watts RMS per channel and 55 WPC peak/4 channels (the Audio20 has 25 watts RMS per channel and 100 WPC peak/4channels).

The suggested Infinity and JBL speakers should be an excellent match for the Sony. A subwoofer is certainly recommended! Would appreciate a photo of how the Sony integrated into your dash, thanks!

cbrea1418

I snaked the wires for the usb plugs to go down the footwells. one on the drivers side (iphone/ipod compatible), the other down the passenger side which is for usb storage devices/ charging. since i have a turn key ignition vs push to start i use the push to start fuse location (always on) as the constant power instead of tapping into anything or connecting it directly to the battery. i do have control through the steering wheel but i have not configured it properly, and i do not want to as it also plays/moves with the dash screen simultaneously. In all honesty i am okay without the use of the steering wheel as the screen is perfectly level with my hands if i rest my forearm on the shift knob. there are a lot of redundancies with buttons in Merc vehicles and im okay with not having them readily avail all the time. the center knob does not function as there is no adaptor to keep its functionality, the center screen either, but i am okay with the trade off as i get much more from the sony unit than i could ever get from the factory radio. also, i put the seat warmer buttons/control unit in the glove box.