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Car Audio Sound Quality Round Table #1

"Panelists consisting of industry experts in home and mobile audio assembled in Scottsdale, AZ, on February 23, 2013, to discuss topics related to achieving sound quality in mobile audio, along with ways to grow the mobile audio industry."

Source: // whitledgedesigns

See also Earl Zausmer's BMW-540

"It sounds harsh and not pleasant." -- Verbatim email exchange on unpleasant-sounding 'all-digital' system and suggested fixes:

This regards digital-audio technology (D-AT) in general, we believe, not any particular manufacturer or equipment. The audibly "harsh and not pleasant" plight of D-AT, it reasonably seems, would be manufacturer-agnostic. The digital quantization of inherently (necessarily?) analog modes has esoteric roots (and debates) that span millenia, beyond "quantum mechanic" psyence and theoretical quantizability to Greek atomicity in lore. At what slices and dices fine enough, or in sufficient quantity, do the parts indiscernibly reconstitute or even tolerably represent any whole? (ref Georges Seurat, divisionism / pointillism)

1. Initial email from an Audio Enthusiast in Amsterdam, early 2020

Hello, I have an audi Q5 with following audio equipment. It sounds harsh and not pleasant.

  • Audison Bit One.1 DSP
  • Audison Voce AV Quattro – 4x200W amplifier, two pieces
  • Hertz Mille ML 280 - 28mm Ndym tweeter,
  • Hertz Mille ML 700 - 70mm midrange
  • Hertz Mille ML 1600 - 165mm Ndym woofer

At home I have unico secondo tube amp + revel F206 speakers, sounds beautiful.

Now I’m looking for tube amp for in the car to replace audison amp. Also, I’m wondering whether replacing the amplifier in the car will improve sound, or do I need to replace the speakers also?

2. Initial response from Michael Milbert

I would start by using a tube amp as there is [arguably] a bigger difference between tube vs solid state than amongst speakers.

3. Audio Enthusiast:

Hi Michael, Thank you for your response. Is there anyway to test it with my current speakers (just replacing the amp)?

This is my current setup [image attached, see full-size diagram, upper-left]

4. Michael Milbert:

BaM-235ab and Liquid amps accept unbalanced audio signal on RCA connectors. Only 1.5Vpp is necessary to drive the amps to full power output (attenuators allow for much higher voltage levels). If your Audison Bit One can provide analog audio signal output, either BaM or Liquid should work directly in place of the Audison amps. If only a digital output is available from Audison Bit One, a DAC will be necessary between Audison Bit One and BaM or Liquid. From your diagram I presume your speakers use passive crossovers.

5. Audio Enthusiast:

The speakers use DSP crossovers inside the bit one, and a digital signal is fed from the bit one to the quattro. The DAC is inside the quattro amp. But the bit one does have 8 low level analog RCA outputs, see

So I would need to add some passive crossovers, which is not a problem.

6. Michael Milbert:

If you were to use a BaM-235ab, you might try feeding highs+mids (output mixed, as a stereo pair) from Bit One to L/R channels of BaM, then using passive crossovers between L/R tweeter and honker. This would let you keep much of your investment, but insert the BaM-235ab where it would make most sense, most audible impact.

7. Audio Enthusiast:

Today I removed the audison amps from my car, and just connected my home amplifier (unison secondo, which has two tubes), with three way crossovers directly to the speakers. It was hooked up as follows: pillars tweeters 4000+ Hz -3dB, dashboard mids 300Hz-4000) -3dB, front and rear doors lows (0-300Hz) 0dB. I simply used an extension cord to my home outlet for the 220V of the unison amp.

This sounded beautiful, and almost as good as in my house connected to my revel F206 speakers.

Unfortunately, this unico secondo home amplifier works only on 220V and not on 12V. However, it does mean that the audison amplifier was causing the bad (harsh, unmusical) sound, and not the speakers.

Regarding your suggestion of using the BaM-235ab for the high and mids (pillar and dashboard speakers, and the audison for the low (doors and trunk), is a possibility, but I'm quite hesitant to keep using that audison amp, knowing that it sounds bad. Do you have another suggestion?

Met vriendelijke groet, // Best regards,

8. Michael Milbert:

The BaM will certainly operate full-range and sound great. Because it has transformer-coupled output, like most tube amps, the lowest bass is probably not going to sound as taught and controlled as with transistorized amplification. If the unico tube sound is to your liking, the BaM is probably in that ballpark as it originally came from home audio: Tubey warm with airy soundstage and lifelike sparkle.

Glad you're hearing progress! Your finding echoes ours: The 'technical perfection' of digital is not necessarily pleasing to hear.

I would like to post our email exchange on, without your personal details, as it may help other people also suffering digitalia. Would this be okay with you?

9. Audio Enthusiast:

Sure you can post it. It was a huge revelation for me today. When I first received the Audi after the installer had put in the complete audison system (total cost $11k, 5 years ago), I was immediately disappointed. Then, I tuned the Bit One DSP with all possible settings and eventually found that the best of the worst was everything flat (timing and eq). But it was still awful. So today I removed the audison amps and dsp, and put the tube home amp (cable to the 220V socket of my home), plus two passive three way filters, and immediately bliss, on all songs and genres. And it's not like the audison stuff was cheap, on the contrary. Anybody interested in two reluctantly used Audison Quattro amps?

If I would use the bam for high and mid, what transistorized amp would you recommend for low (100-300 Hz) door speakers, if I add an active sub in the trunk also (40-100 Hz)?

10. Your turn, dear reader -- Anyone have a suggestion for a great-sounding transistorized amplifier? Please email us your experience and specific details and we will post here. An interested car audiophile in the Netherlands awaits.

Milbert Amplifiers, The Most Musical Amplifiers. Made in USA since 1986.
Milbert Amplifiers
The Most Musical Amplifiers
Made in USA since 1986