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      06-15-2014, 10:23 PM   #1
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Drives: 2015 320i
Join Date: Apr 2005
Location: Ft Lauderdale, Florida

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Notes on a 2011 E90 M3 with HiFi and Audison Prima AP8.9 bit

One of my suppliers lent me a brand new Audison Prima AP8.9 bit DSP/8ch amp for testing. Called one of my audiophile friends to ask if he wanted it for a couple of weeks, installed at no cost. After 2 nanoseconds of thinking about it, he accepted it.

Parts to be installed:
  • Pre-installed full 100% PnP HiFi harness with center speaker wiring
  • JL Audio C2-400x coaxial as center speaker
  • OEM center speaker trim and PnP cable

Center speaker install -OEM center vents trim removed

Center speaker installed in OEL center speaker existing mount (standard on all E9x):

Centyer speaker cable installation - using wire "worm"

Insert wire worm towards passenger-side:

Connect speaker and cable:

Pass cable from passenger- to driver-side...

... then towards trunk under door sills:

Insert center speaker cable OEM pins (P/N 61130006663) into black OEM amp sub-connector slots 39 (+) and 40 (-):

Size comparison between AP8.9 bit and HiFi OEM amp:

AP8.9 bit plugged in:

That's it.

  1. The AP8.9 bit accepts balanced inputs directly.
    No need for any converter for the HiFi balanced inputs to be accepted. However, after the car went to sleep and then came back the AP8.9 bit volume raised uncontrollably several times. Either this unit was defective or it is really not 100% balanced inputs compatible -the DC offset in the signal may be causing random electrical changes in its inputs section. I experienced the same problem in a 3SIXTY.2 about 8 years ago. I solved it by using a Matrix line driver/balanced-to-unbalanced converter.
  2. Its constant 12V port actually does not require constant 12V as its settings are kept in memory for days. This means that the OEM amp 40A 12V power line can be used directly as the AP8.9 bit power line: no need to connect this line directly to the battery. The OEM amp 12V power line is not fully constant- it goes to sleep in about 20-30 minutes after the car is turned off.
  3. Easy software setup, crossover settings and parametric EQ.
    A laptop PC is required and connection is via USB. Very intuitive graphical interface, menus and feature descriptions and operation. With the HiFi system there is no need to perform input level setup or any signal correction -all are skipped. Input level set to 2V. Seven channels of output used in this particular application -set all the mid/tweeters and center speaker as woofer with high pass crossovers at about 175Hz at 18dB slope, underseat woofers set as subwoofers with bandpass crossover at 50Hz at 24dB and 200Hz at 18dB slope

    One thing: after all the settings are done and saved into unit, the AP8.9 bit must be unplugged from the OEM amp connector and re-plugged it for the settings to be enabled. Otherwise, once the software is exited there will not be any sound from the unit.
  4. Sounds much better than the HiFi OEM amp but...
    Excellent front stage, stereo separation and clarity from the OEM speakers and JL Audio center speaker, solid bass from the OEM woofers. Compared with the OEM HK I would say that it is better but not by much. Compared with the EPS it lacks volume but otherwise it is also better sounding just by being much more customizable. However, this unit MSRP will be in the $1000 range so $875 for the HK looks like a bargain -especially to the F30 HK 600W/16-speaker system. To me this unit should be in the $400 range, $500 tops just because of the brand. Seriously. The stated 35W RMS at 4ohms and 65W RMS at 2ohms sounded less loud than the 18W RMS/30W RMS of the MS-8. And to me, the MS-8 still wins in sound improvement just because of its magical autotune. And the MS-8 street price is in the... $400 range (but it is unreliable, in the other hand). Unit gets really hot very quick. For the underseat woofers to have a serious bass impact, the parametric EQ between 50Hz to 200Hz must be boosted out to the max and beyond -after maxing out all the possible input and output levels. To me, that is not the sound of 65W RMS to each woofer. But once that is done the OEM woofers sound much deeper and tighter than the OEM amp.

I ended up swapping this AP8.9 bit for a XD600/6 with a CDT CS-256 as the center speaker passive CenterStage crossover:

Second notes:
  1. There is simply no better bang for the buck for the HiFi system than the XD600/6. Again and again. The improvement in sound quality, volume and impact over the OEM amp is absolute. Just set the crossovers to front/rear to 175Hz HP, minimum gain and underseat woofers to 200Hz LP 10 o'clock gain and that's it. The level, quality and deepness of the bass out of the OEM woofers is absurd - and that is with the OEM Bass adjustment at center (0).
  2. The addition of the CS-256 driving the center speaker is a great add-on -it only uses the tweeter of the coaxial speaker. It creates a fuller front stage by using the windshield as a reflective surface. And it nicely compensates for the not-that-great OEM tweeters at the front doors. Output and crossver values are adjustable by switches at the crossover module -settings were high output, medium crossover.
  3. Compared with the AP8.9 bit, clarity and separation are down a notch, but volume and impact are way up -both sides are understandable. One unit has DSP with multiple adjustments which the amp lacks, the other uses a much better amp architecture with several times the power output of the DSP/amp unit.

    But again, the AP8.9 bit would have been a great unit for $400. At $1000 it is just overpriced for what it offers.

Last edited by Technic; 06-16-2014 at 12:26 PM.
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