Well guys, today I did a bit of serious listening in my car. I was evaluating 2 things, my signal path, and my midrange positioning.

My signal path is as follows:
Alpine DVA-7996
Audio Control Four.1i
Audio Control DQX
Audison VRx2.400
Focal 165W3

I honestly thought that I would use the Four.1i on most CDs that I listen to. But more often than not, I ended up using it as a line driver.(I thought I was, more on this later) I just don't see the point of adjusting 5 bands of E.Q. for each source disk. I've spent most of my tuning time working with the DQX, trying to get the system somewhat neutral so ALL disks sound good. The Four.1i was starting to bother me, I'm very concious of the fact that every component in the signal path (no mater how good) changes the source signal in some way. So I performed a little experiment, I removed the Four.1.

A little background on the Four.1i first. I thought that tonal control over each disk would outweight the loss in fidelity. You'd think that after years of high end home audio, I would have learned. But no, I needed the little in dash gizmo to appease my worries. Bad move! When I removed the Four.1i from my sinal path, I recieved a health boost in fidelity. Everything sounded more natural, and of course my imaging improved. It was a very nice improvement, one that I'm relieved to hear.

Now anybody interested in the difference in line level to the back, read on. I initially set up the input gains on the Four.1i with the 7996 volume at 35 (Max). I used the little lights on all my gear to level match each component with dynamic music playing. I then sat down and listened to every stage to verify that nothing was being overdriven.(Clipping) I just want everybody to understand this, because what I'm going to say next is surprising.

When I removed the Four.1i, I lost no signal level to the rear. In fact, with the head unit at maximum volume, it appeared to be a bit louder. I had no noise induced in the line at low or high volumes. Why did this surprise me? The 7996 has 4 volt pre-outs, and the Four.1i has 9.5 volt pre-outs.(As advertised) The only explanation for this is that Audio Control designed enough headroom on the output stage for massive equalization. For example, you can run your deck at full output cleanly, and then add 12db of boost to let's say 80hz. Because of this, I'm going to assume that my head unit's output was attenuated slightly with the input gains on the Four.1i to give the nessesary headroom. Anyone care to comment on this?

Anyway, I'm happy using the output directly off of my DVA-7996 to the rear without a line driver.

The next stage was playing with the midranges in my 3 way component set. I started with only the midrange connected to the X.O. and placed the drivers on the floor next to the kicks. Just to get a baseline, I listed for a few songs. Then I started playing with the angles and heights of the mids. I incrimentally raised and tilted the drivers listening to the same music over and over again. I certainly learned a lot, and I recomemd that everybody try this in they're own car.

Next I connected the tweeters. I listened with them connected both in and out of phase. I chose what sounded the most natural to me. Then I did the same with the mid-bass drivers.

I'm not going to say exactly how I've chosen to set up my speakers. The reason is that I want to encourage other people to find they're own answers. What works in my car may not work on your's. I do believe that the mids in the kicks is the way to go though. I tried putting them everywhere I could think of today, but the kicks just blew me away! Thanks to everybody here on the board (especially Tom) for the great advice on how to set up the front stage. I used all of it!

So to answer my opening comment, as little as you can get away with. KISS all the way [img]graemlins/thumb.gif[/img]

Adam

Adam, I also had a similar problem as yours. I have a small 5 band Orion eq underneath my head unit which has now been bypassed becuase it was initiating alot of noise into the system.
Although I miss being able to adjust the equalizer for every song, I definately don't miss the induced noise. Since bypassing this eq, everything is alot quieter now. All equalization is done through my Orion DEQ30 which is in the trunk.

__________________
"The purpose of art is not the release of a momentary ejection of adrenaline but is, rather, the gradual, lifelong construction of a state of wonder and serenity"......Glenn Gould

I'm just thankful that I figured this out BEFORE I perminantly hacked up my dash to mount the EQ. [img]smile.gif[/img]

I agree.. The more devices you place in the signal line, the more coloured your music will be. Even the best quality gear can have negative results. I got a 4.1i for the same reasons you did. I have not had a chance to see how it performs, (I hooked it up briefly for testing, but have not used it to it's potential) as my system is in pieces right now. I'd be curious to see if I'll have the same results once everything is properly installed. The primary reason I got it was to have balanced, high voltage outputs for my Xtant (which can accept up to 17V balanced), and to have some control in the drivers seat. I'm hoping it will work out well, but as of right now, I have not made any permenant modifications in order to utilize the EQ, so I will likely do some careful listening before I decide to mess up my dash [img]smile.gif[/img] As of right now, it is my only EQ, but I am scoping out some trunk mounted eqs also. I'll be in the same sort of situation. Too many processors in the signal path. I got my 603x to keep things simple, I just hope I wont complicate things with multiple processors.

__________________
2000 Acura 1.6EL Premium<br />IASCA SQ Competitor - Street Smart 1-600W<br />Sound Domain Page: <a href="http://members.sounddomain.com/turbolemon" target="_blank">Mike's Acura</a>

I will be installing my Alpine PXA-H700 soon....one chassis...3 optical digital inputs...I'm pretty anxious to see how it sounds as all x-over, eq'ing, time allignment, DSP(5.1, DTS, Dolby Surround Pro-Logic II), and high voltage outs to the amps - "are all in one box" to simplify wiring and hopefully protect the integrity of the signal as well... Time will tell!

__________________
"The taste of low quality lingers long after the satisfaction of low price" <br /><br />////ALPINE - Audison - Wavelength - Focal - Phoenix Gold

I considered the PXA-H700 as well. What detered me from it was that I would be giving up the use of the Burr-Brown DACs on the deck. The PXA uses 16 bit D/As and the DVA-7996 uses 24 bit D/As. But I have to admit, I would love to be able to do an A/B comparison between the PXA-H700 and my Audio Control DQX. Want to drive to PEI Islandphile?

Adam

You give up the DVA-7996 DAC's performance when you use the DQX anyway.. Sense the system is only as good as the last component, And the DQX has both A/D's and D/A's. Hopefully AC uses good parts in there equipment.

[ October 27, 2003, 07:36 PM: Message edited by: chev2 ]

__________________
David
RIP Sebring, Hello VW

Line level output is not a measure of fidelity. However signal level mismatches between processors and amplifiers can result in an increase in signal degredation which can result in a loss of "fidelity". This is why most advocate the KISS approach. Less equipement means fewer errors in signal level matching.

The Audio Control piece is a very high quality unit and I find it hard to believe that it would degrade the signal significantly.

PEI330, you said that you had the deck's output maxed out at full volume. Is the signal clean at the max volume setting??? Alpine decks usually distort at full volume.

Another thing to consider is a possible signal mismatch between the the 4.1 and DQT or the DQT and the amp.

Consider this... If the maximum input signal of a device is 2V and you drive it with a 4V signal, you will suffer an additional 6 dB of signal degredation.

Now consider further that this loss occurs with each signal mismatch. So in most cases, the more the devices the more this becomes an issue..

You need to use an ociliscope (sp) when setting up an system. The lights on the AC units are a crude method of measure.

If I'm not mistaken, I believe the DQX will output only 5V of signal. I believe it can accept pretty much anything the 4.1i can give to it, but would it attenuate the input signal to output the 5V ? I'm not too sure if what I'm thinking is the way it works, but that could be the bottleneck as far as output voltage. 5V compared the the 4V the deck supplies would not be a huge difference. The extra ~5 volts the 4.1i was providing would be pretty much wasted if that was the case.

__________________
2000 Acura 1.6EL Premium<br />IASCA SQ Competitor - Street Smart 1-600W<br />Sound Domain Page: <a href="http://members.sounddomain.com/turbolemon" target="_blank">Mike's Acura</a>

lemonlime-I agree the more stuff in the signal path the more colored the path will be (coloured rolls off the keyboard so much nicer).
chev2 is spot on, once you put something between the power amp and the high priced head units drive circuit then you are giving something up from the source.
mqqball has VERY good info also though an O-scope is a little much (but if you want to get all the sound you shelled out the big bucks for... borrow one!). Though I will say that many like KISS because every component adds an interconnect with 2 RCA's and every stretch of copper and every component add sonic grunge. All you can do is use the least equipment that you can get away with.
I had an EQX in my system that encouraged me to tweak and tweak until I completely screwed up the sound. Yes AC uses decent parts but the PPI DEQ-230 I now use adds less sonic grunge. I don’t like EQs, but if your car has a hot freq band or you compete in RTA then carry on!
Me, I like KISS because they are touring with makeup on again!

__________________
MECA SQ

www.cardomain.com/memberpage/769882

I don't know what your problem is, but I'll bet it's hard to pronounce.