whchan
Dec 18 2003, 11:08 AM
Since many new cars nowadays no longer have a DIN (place) for installing HU, I was just wondering if it is possible to built a system with the same level of SQ (for roughly the same amount of money) as without a decent aftermarket HU? People here have suggested that you can still connect the factory CD player to an amp but in terms of SQ would it be affected since most aftermarket HU have a pre-amp while factory ones doesn't?
[ December 18, 2003, 09:09: Message edited by: PM ]
shiny_car
Dec 18 2003, 01:03 PM
QUOTE
Originally posted by PM:
most aftermarket HU have a pre-amp while factory ones doesn't?
every HU will have a preamp. if you separate out the sections of a HU, they'd include the 'source' (CD transport and tuner), 'preamp' (volume control, processing), and 'amp'.
it's the last bit that always bothers me. if you rely on the high-level outputs (ie: speakerwires that are converted to low-level RCA outputs via a converter) then the music signal MUST pass through the inbuilt amps. and unfortunately i believe this is where you lose SQ esp in terms of dynamics, channel separation, and frequency response.
and when you use proper RCA preouts, you bypass the 'amp' section, and send the signal directly from the preamp.
it's like comparing running your speakers directly from the HU vs off an amp. sure, you don't place the same high-current demands on the inbuilt amps by using the speakerwires to send a signal to an RCA/amp compared with running speakers, but you just 'know' it's not quite as good.
and unfortunately many stock HUs are plain cheap, so the quality of everything is not up there with a good aftermarket HU.
not to say you'd end up with crap SQ, just not quite as good...IMO.
[ December 18, 2003, 11:05: Message edited by: shiny_car ]
Mickee
Dec 18 2003, 01:49 PM
I agree with Shiny.
IMO, after speakers, the head unit has the most impact on SQ. I'm sure most of us who have upgraded head units (leaving everything else the same) have noticed the distinct difference in sound between different head units, and the improvements a good quality head unit makes to a system.
Being in the market for a new car myself, it really bugs me that so many new models are featuring 'integrated' head units. What is really needed is for someone (a dedicated company, or each car manufacturer) to make available aftermarket dash panels which feature a DIN slot for the head unit which are specific to a vehicle make and model.
Michael
FLiPSiDE
Dec 18 2003, 05:51 PM
just speaking from personal experience and not being much of a purist
i was using my stock headunit for over a year with a david navone RCA adaptor and a 3:1 voltage overlap as he recommended (RCA adaptor set to near 9v out and amps 3v sensitivity gains set to right on 0 or 3v sensitivity)
since then a few months ago i bought a clarion DXZ-835MP which is thier 2nd top model (after the one t-bro has whos model # escapes me)and to me the old set up sounded as good if not better than it does today running off a clarion 835MP 4v outs and the gains tweaked up a bit
without the 3:1 gain setup from the navone it does sound a bit weaker.. the volume control never needed to be turned up very high and went to audibly unbearable levels without distrotion.. now even with gains raised a little its not as ultimately loud and doesnt seem to have the OOMPF (for lack of a better word) it once did
i think T-bro can also verify it tho he hasnt had a realy good listen to the system since the deck change but there wasnt a problem before hand
the only thing that forced me to change decks was a noise issue on the aux-in adaptor i was using for my PS2.. no such drama with the clarion unit
anywhoos just my 2 cents from someone who's been there and done it
T-Bro
Dec 18 2003, 06:26 PM
yes in flipsides case there wasnt any immediately noticable improvement from going from the stock deck with converter, to a high end Clarion with its 24-bit goodness, though a serious listen may yield something - but yeah of the owner cant hear it, it doesnt exist haha.
which is a little funny because i have the same speakers (Boston Pro 6.5) and each time ive changed the headunit, i have picked up differences as have another friend who is into the whole audiophile thing. differences have included a more fluid and silky sound, greater ambience, improved composure at high volumes, marginally tighter imaging, and revelation of slightly greater detail in the midrange. possibly such improvements require a pod setup which allows the critical midrange to be on-axis for this stuff to be picked up, i dont know. but for me headunits do make an audible difference which is why i didnt mind paying up for it.
but yeah the previous stock deck and navone converter in flipsides mini were the goods, nothing about it was obviously deficient and it was certainly fun to listen to with some engaging sound quality given the stock locations - and it was so TIGHT at high volume, midbass and sub-bass attack were neck snapping (still is mostly)! so i copied the fool, upped my amp power, lowered my crossover point, and increased line voltage - OONST! haha
so yeah given how cars are going, i wouldnt be totally depressed if i was stuck with a stock deck as alot can be done with them.
would there be benefits of seperating the preamp from the dac and cd transport like in home audio?
Macca
Dec 18 2003, 11:49 PM
As with regard to sepperating the Pre amp, i would only see this as a problem if your pre amp couldnt get the power supply from the HU it needed. BUT on another note, who makes a decent outboard pre amp. i cant think of any.
Cyberpunky
Dec 19 2003, 12:35 AM
In the US a few ppl have got factory HU modified to get a digital out, which maes HU just a transport and depending on what DAC is hooked up, can make factory HU better than many top of range HUs. Although an outboard DAC isnt cheap it is one way of using a factory radio and getting awesome results, and in no way compromising on SQ.
It also allows all the steering wheel controls and other things that are intergrated into many new factory HUs to kepp working. If I ever get a late model or new car I am seriously thinking of going down this road using my Apogee DAC. I can just picture the look on ppls faces when a factory HU sounds better than there aftermarket system lol
peace
Cyberpunky
golf_bht
Dec 19 2003, 02:20 AM
Hey cyberpunky, are there anyone in Australia that can perform the trick? I would like to have a digital out from alpine 9815. the DA converter in this HU is so crap that I was trying to sell it in the first few days I brought it from the shop but I still need the time correction.
EcHo2134
Dec 19 2003, 02:39 AM
go to an authorised repairer for your type of head unit..and ask them...
I'm fairly sure they can do it..cost may be high due to labour rates though.
whchan
Dec 19 2003, 11:08 AM
QUOTE
Originally posted by Cyberpunky:
In the US a few ppl have got factory HU modified to get a digital out, which maes HU just a transport and depending on what DAC is hooked up, can make factory HU better than many top of range HUs. Although an outboard DAC isnt cheap it is one way of using a factory radio and getting awesome results, and in no way compromising on SQ.
It also allows all the steering wheel controls and other things that are intergrated into many new factory HUs to kepp working. If I ever get a late model or new car I am seriously thinking of going down this road using my Apogee DAC. I can just picture the look on ppls faces when a factory HU sounds better than there aftermarket system lol
peace
Cyberpunky
How to get one of those DAC and approx. how much is the cost?
T-Bro
Dec 19 2003, 01:26 PM
actually Jaycar are selling a 'valve preamp' kit at the moment, that would allow you to create your own and have bragging rights to having a valve in your signal chain! tempting, but for me my clarion does the job fine - maybe a future project.
Slayer
Dec 20 2003, 02:31 AM
ok guys maybe not directly related but kind of on the subject I've just upgraded my headunit to a alpine 9815 from a jvc-sx995. I noticed a change in sound between them but unfortunately my sub seems much quiter than before this is with the headunit sub volume all the way up and more gain on my amps.
Is there anything I can do to boost the signal or will it degrade sq?
shiny_car
Dec 19 2003, 04:43 PM
QUOTE
Originally posted by Slayer:
Is there anything I can do to boost the signal or will it degrade sq?
it's possible the jvc had some inbuilt colouration to the sound, boosting the low end artificially. or else the alpine has a low end response that drops off.
either way, it's probably safe to simply up the gains to acquire the sublevels you're after. alternatively, play with the parametric EQ. tune the gains properly, and you won't have probs with overpowering the sub or clipping the amp.
re: outboard DACs. given home audio outboard DACs typically cost over $1K, and commonly $2~3K for a top one...i'm sure you could find a similar cost for a 12V incar one.
golf_bht: i gather you can't change your HU to the 7998 that features a digital output.
golf_bht
Dec 19 2003, 05:46 PM
True but 7990R still doesn't have time correction if you didn't hook it up with PXA-H700 and I do believe that Apogee 24/192 will dound better than PXA-H900 but without time correction So I only need a preamp with time correction
Bassaholic
Dec 19 2003, 06:31 PM
QUOTE
Originally posted by Slayer:
I noticed a change in sound between them but unfortunately my sub seems much quiter than before this is with the headunit sub volume all the way up and more gain on my amps.
Is there anything I can do to boost the signal or will it degrade sq?
Yes, if the alpine doesn't put out quite as much RCA voltage, then you can solve the problem simply by setting the gains properly - ie turning them up to the right level, or turning down the gains on the front stage (and rears if applicable) and turning up the volume on the headunit a little higher.
T-Bro
Dec 19 2003, 06:48 PM
ive noticed that some headunits have weaker bass - no reason or explanation, just the way different audio components are. when i went from bottom of the range kenwood to top of the range clarion, the sub-bass tightened up and was better defined.
check to make sure no EQ or tone settings are on and affecting bass response, otherwise its just the 'flavour' of that head unit
[ December 19, 2003, 16:50: Message edited by: T-Bro ]
Bassaholic
Dec 19 2003, 07:22 PM
QUOTE
Originally posted by T-Bro:
ive noticed that some headunits have weaker bass - no reason or explanation, just the way different audio components are. when i went from bottom of the range kenwood to top of the range clarion, the sub-bass tightened up and was better defined.
check to make sure no EQ or tone settings are on and affecting bass response, otherwise its just the 'flavour' of that head unit
I think it has a lot to do with the sub level controls - but tone could be an issue as well - some headunits default with certain tone settings on, so people may get used to having the tone controls on without even knowing it
Slayer
Dec 19 2003, 10:04 PM
thanks for the replies guys, only problem is the gains on my amp are all the way up on the coustic 481qe bridged running a jl 12w3v2 (yes I know it's slightly underpowered) thats a good idea though lowering the gains on the front stage so i can turn the volume up more will see how that goes
i did often have the loud feature of the jvc on which added lots of bass (argh don't shoot me it just sounded better while driving) I'm guessing the equivelent on the alpine is mediaxpander but that sounds pretty bad to me so I'm leaving it off. I may also need to play more with the equaliser but with limited knowledge using it i figured I'd stuff the sound
FLiPSiDE
Dec 20 2003, 05:06 AM
QUOTE
Originally posted by Slayer:
i did often have the loud feature of the jvc
well that would explain it.
gooki
Dec 20 2003, 12:55 PM
golf_bht
You might be beter of just buying a new headunit.
Why?
1) It's highly likely that the time alignment on the Alpine 9815 is after the internal DAC, so if you mod it to have Digital Out, you may very well loose all timealignment ability anyway.
2) Or if it is infact a true digital timealignment and runs prior to the DAC, then the alpine will be pumping some non standard digital signal to a non standard DAC.
Why is this? Because most external 12 volt DAC's are built for 2 a channel 44.1/48 PCM digital signal (or DD, DTS). Hence with time alignment it will be putting out a proprietry 2/4/6 channel PCM digital audio signal (if it's a true digital time alignment)
2) You will also loose all control of the volume from the source unit unless you mod it for digital out, then re-wire the output of the external dac to run back into the headunits PCD board.
3) You can pick up external 12volt DAC's from around $200USD + shipping on ebay. Got my nakamichi DAC 101 installed for the first time a few months back. Sounds great, but since I'm using the headunit as the transport, I loose all control of the volume (no I'm not to keen on hardwiring my DAC into my headunit), so it's sitting on my self waiting for my nak CD Changer controler so I can feed it into the aux input on the headunit.
shiny_car
Dec 21 2003, 02:24 AM
QUOTE
Originally posted by gooki:
1) It's highly likely that the time alignment on the Alpine 9815 is after the internal DAC, so if you mod it to have Digital Out, you may very well loose all timealignment ability anyway.
yes, this is a point i didn't think about. or at least, with the 7998, when i use the digital output, all the internal processing features (ie: EQ, TA, xovers, MXpander) are bypassed and become unused (instead i rely on the alpine outboard processor). so i figure using an alpine with an existing digital output converts your HU into a CD transport (and tuner) only. then you rely on the Ai-NET connection to control the preamp section in the outboard processor (PXA).
QUOTE
2) Or if it is infact a true digital timealignment and runs prior to the DAC, then the alpine will be pumping some non standard digital signal to a non standard DAC.
Why is this? Because most external 12 volt DAC's are built for 2 a channel 44.1/48 PCM digital signal (or DD, DTS). Hence with time alignment it will be putting out a proprietry 2/4/6 channel PCM digital audio signal (if it's a true digital time alignment)
note that the 9815, amongst other alpine components, features 6 DACs according to the specs. (hmmph, my 7998 only has 2 .) the PXA processors typically have one DAC per channel too.
anyway, just some interesting (or not so interesting) facts about alpine equipment.
gooki
Dec 20 2003, 08:45 PM
Thanks for the info shinny.
Cyberpunky
Dec 22 2003, 01:28 AM
All of the above info is correct, as a dig out makes any unit just a transport. This means you need some form of level control between DAC and amps. I use an Audio Control MVC but you could use any RCA level adjuster.
Id put money on TA being after internal dac. As all Alpines that have had dig out use pcm (stereo units) that i have played with. Any CD player can have a dig out fitted but how much and who does it, I have no idea as never enquired, and as many high end CD players have dig out, its not an issue for most ppl wanting to use an outboard DAC.
Anyway its just an idea ppl in US are using and thought I would point it out as original question was about what can be done for SQ with factory HU and this is a no compromise solution although not a cheap solution .
peace
Cyberpunky
Macca
Dec 22 2003, 03:37 PM
Well how about my case, how or could i mod the Pioneer HU, to digital out, and use the DAC in my PXA-H600, it has its on volume control on its seperate control unit ect. Would be an interesting lil project.
shiny_car
Dec 25 2003, 02:48 AM
QUOTE
Originally posted by Macca:
Well how about my case, how or could i mod the Pioneer HU, to digital out, and use the DAC in my PXA-H600, it has its on volume control on its seperate control unit ect. Would be an interesting lil project.
you already DO utilise the 20-bit DAC in the PXA-H600. the analogue from the pioneer feeds via RCAs to the PXA, then is converted to ditial via an inbuilt ADC. digital processing takes place then the signal is converted back to analogue via the DAC.
you could theoretically convert the pioneer to a CD transport with digital output. this will avoid relying on the pioneer's DAC, potential signal loss via the RCAs, then the additional signal conversion back to digital via the ADC.
you would need to continue using the PXA's hardwired remote to control the volume, etc coz the system's preamp is within the PXA (ie: volume setting, etc, etc). only an alpine Ai-NET HU lets you control the PXA's preamp from the HU controls.
[ December 24, 2003, 12:53: Message edited by: shiny_car ]
however, would you hear the difference between different DAC's?
Bassaholic
Dec 25 2003, 10:21 PM
QUOTE
Originally posted by ix:
however, would you hear the difference between different DAC's?
Not neccesarily.
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