What is it that makes a very good head unit sound top notch?

[dsw1204]

Okay, here is my story. I have owned a second-hand Eclipse 55040 and have been extremely happy with it's performance. The sound that comes from this head unit is phenomenal. The only drawback is that I cannot play music from my Ipod Touch or Iphone 5S through it. So, I looked for another head unit that had the same sound quality as the 55040 but would accept music from Ipods and/or Iphones. I ended up acquiring a NOS (new, old stock) Eclipse CD8454 because it had an AUX input. But, the AUX input is in the back of the unit which will make it a bit cumbersome when hooking up my auxiliary devices. I have not yet installed the CD8454 into my car.

Looking at some of the newer head units and I see it is much easier to use the Ipods and Iphones through these units. But, I am not sure about the sound quality of these newer head units.

My question is: What is it about the Eclipse 55040 that makes the sound quality so amazing? Is it the 8V preouts? Is it the 24 bit DAC's? Is it something else? And, are there any head units out there currently that match the SQ of the old Eclipse units (I am assuming the SQ will be as good on the CD8454 as it is on the 55040)?

I am really very interested to hear what you guys have to say about this? Thanks.

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[keep_hope_alive Premium Member]

here's the catch, you want to use lossy music sources with compressed music sources and are concerned about sound quality. //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif the best HU in the world will sound nearly the same as an average head unit when you play music through your phone - and the best HU will further expose the distortion/noise/sampling of the compressed music more easily.

i am happy with the new Alpine CDE-HD149BT head unit for sound quality and connectivity.

or you can run two head units if you have a double din opening. then the output from the newer head unit can feed the AUX in on the SQ head unit. i do that with my 2014 Accord - the stock HU feeds the AUX input on my older Alpine.

 

[ciaonzo 5,000+ posts]

It pretty much comes down to the DAC performance. I first became aware of this in the mid 90's when I was running a Clarion DRX9375. I went straight from the head to a trio of Soundstream amplifiers and it sounded incredible. Then, when I had the chance, I added in the outboard processor DPH 910 or 7500 (can't remember) and my jaw dropped when I heard the difference. This was before I tweaked anything. The release of detail and spacial content was unbelievable. The outboard processor had much better DAC's and higher precision clocks to keep jitter low. The signal to noise was something like 109dB, channel separation was far greater, dynamic range much greater... just everything. All because the 1's and 0's went straight from the laser, down the optical cable, and into the higher precision DAC's in the outboard processor. By the time I had that setup tweaked, I didn't touch it for about ten years.

 

[dsw1204]

here's the catch, you want to use lossy music sources with compressed music sources and are concerned about sound quality. //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif the best HU in the world will sound nearly the same as an average head unit when you play music through your phone - and the best HU will further expose the distortion/noise/sampling of the compressed music more easily.
i am happy with the new Alpine CDE-HD149BT head unit for sound quality and connectivity.

or you can run two head units if you have a double din opening. then the output from the newer head unit can feed the AUX in on the SQ head unit. i do that with my 2014 Accord - the stock HU feeds the AUX input on my older Alpine.

Okay, so you are telling me that the music from my Iphone and Ipod will sound lousy because those auxiliary units are poor SQ sources?

 

[dsw1204]

It pretty much comes down to the DAC performance. I first became aware of this in the mid 90's when I was running a Clarion DRX9375. I went straight from the head to a trio of Soundstream amplifiers and it sounded incredible. Then, when I had the chance, I added in the outboard processor DPH 910 or 7500 (can't remember) and my jaw dropped when I heard the difference. This was before I tweaked anything. The release of detail and spacial content was unbelievable. The outboard processor had much better DAC's and higher precision clocks to keep jitter low. The signal to noise was something like 109dB, channel separation was far greater, dynamic range much greater... just everything. All because the 1's and 0's went straight from the laser, down the optical cable, and into the higher precision DAC's in the outboard processor. By the time I had that setup tweaked, I didn't touch it for about ten years.

That is very, very interesting to hear. When you added the outboard processor, did the inboard processor still play a role in the SQ or was it "turned off", so to say? Also, do you know if there is an outboard processor available for my Eclipse CD8454 that I have not yet installed into my car? If so, what is the make and model of it?

 

[ciaonzo 5,000+ posts]

Correct, once the outboard was added the internal was bypassed. If memory serves, I believe Eclipse had something similar. No idea about models or antyhing, and at some point the outboard processors went away because they were able to fit it all inside the heads again. For me to finally give up my Clarion heads was when the 800PRS had come out. The Clarion still sounds better but I couldn't pass up the flexibility that the 800 offers. I believe the sonic match would have been the Stage 4 head and I will grab that someday. KHA nailed it with the compressed, lossy content comment. The files themselves will be the limiting factor most of the time.

 

[I'mPoor:(]

80PRS. Done.

 

[keep_hope_alive Premium Member]

I was going to get into the differences in SQ head units - but got distracted. thanks for filling in!

besides DACs you also have differences in the power supply, component tolerance (5% vs 1%), lower THD, and op amp slew rate. slew rate is generally ignored but so important. it's a huge difference in component cost ($0.30 vs $2.00 per op amp). and while that doesn't seem like much to us, it's HUGE when volume is taken into consideration. SQ costs money, plain and simple. and an SQ head unit is $1k. anything less is making compromises.

i won't use the sub-$600 Pioneer head units. they are poorly made, have terrible crossovers, and are noisy. lots of features as a trade for quality. this is obvious when you consider the properly done version costs $1k.

your best bet for SQ is an SQ head unit with AUX in and a modern head unit for lossy music. there are times where you want the convenience of lossy music and times when you want pure CD bliss.

i'll be moving to an Alpine DVA-9860 with optical to the PXA-H701 processor. That, with Ai-Net, will bypass all of the DACs in the head unit and only use the DACs in the processor. Granted, the H701 isn't the greatest processor around, but it's convenient control is why I like it.

 

[keep_hope_alive Premium Member]

here are some threads with lists of Clarion head units

Eclipse source collection - Car Audio | DiyMobileAudio.com | Car Stereo Forum

One Brand Fanatic-Eclipse - Car Audio | DiyMobileAudio.com | Car Stereo Forum

The Eclipse 2301 DSP may work with your head unit.

An old classified:

http://www.caraudio.com/forums/car-audio-classifieds-old-replies-only/496533-eclipse-cd8053-w-2301-dsp-cheap-ultimate-sq.html

 

[The Camry]

So do all the DAC and whatnot of the head unit matter when your hooked up to a sound processor like say an ms-8?

Currently i run a Excelon KDC-X598 with a newer gen ipod hooked up through a usb cord and apple lossless files. Id like to get an ms-8 soon. Does a sound quality HU matter at that point? Will the processor clean up any noise and use its own DAC(not sure if it has one or even how processor work tbh).

Can you have a 100$ walmart head unit hooked up to a sound processor and have it sound the same as an 80-prs hooked up to a sound processor? Do the sound processors De-eq everything? Just how much of the headunits features and internals matter at that point?

 

[keep_hope_alive Premium Member]

So do all the DAC and whatnot of the head unit matter when your hooked up to a sound processor like say an ms-8?
Currently i run a Excelon KDC-X598 with a newer gen ipod hooked up through a usb cord and apple lossless files. Id like to get an ms-8 soon. Does a sound quality HU matter at that point? Will the processor clean up any noise and use its own DAC(not sure if it has one or even how processor work tbh).

Can you have a 100$ walmart head unit hooked up to a sound processor and have it sound the same as an 80-prs hooked up to a sound processor? Do the sound processors De-eq everything? Just how much of the headunits features and internals matter at that point?

good questions.

when you use the RCA or speaker outputs from a head unit - you're using the DAC's of the head unit. once the signal becomes analog - it's already been processed by the head unit. the only time you bypass internal DACs is when you have a digital output from the HU that is sent to an external processor with digital in. that is not common. I can do that with select Alpine head units.

an external processor cannot undo the HU DACs signal - nor can it "clean up" the output from a cheap head unit.

Alpine has some head units where it gets a digital output from the iPod, using internal DAC's. but i'm not sure if the digital out (from the DVA-9861, for example) converts the iPod signal to analog then back to digital before sending on the optical output. certainly, any analog aux input would be converted.

there are processors with digital inputs, but you cannot control the volume of a digital source from the source - you have to use the processor volume control. one exception is Alpine - who let the head unit communicate with the processor for volume control remotely.

in SQ, simple is better. you only want one conversion and you want it to be as good as possible. getting a great head unit with awesome internals and needed processing is doable for a grand, but even then you are trying to make a ton of adjustments through a tiny screen with 1 or 2 lines of text. the high-end Pioneer DEX, Clarion DRZ, Eclipse, Alpine F#1, McIntosh, Denon, etc. are very simple displays with very tedious setting access/tuning.

i just want a great head unit ($1k range) with a larger remote display for tuning - one that can be disconnected when not needed or left connected for adjustments on the fly.

 

[keep_hope_alive Premium Member]

i really enjoyed the old school (1996) Alpine gear but it was analog and thus noisy. great DACs but when you have a DAC then ADC then DAC you get imperfections

Alpine CDA-7930

Alpine ERA-G320

when i ran old school head unit with a newer processor, i used a cd changer with optical out for a "cleaner" source. it was a very noticeable difference.

Alpine CDA-7930 in dash (RUX-C701 in sunglasses holder)

Alpine CHA-S624 in glove box

Alpine RUX-C701 in sunglass holder

I ran several head units (over 20) with the various processors and each one had merits and short comings. Noise varied as well. The older CDA-7939, CDA-7949, and DVA-7996 all had optical out but were CD only and age took its toll on reading CD's (laser requires replacement).

My goal with moving to a DVA-9860 or DVA-9861 is to regain optical output and maybe take advantage of DVD-Audio.