Has anybody checked the voltage of the preouts ofthe factory head unit? I need to decide whether or not to buy a line driver... I know I should have tested the line outs when I installed my MP3 player but I didn't have the wiring diagram back then.

I appreciate your help,
-Alt

 

well first the factory radio does not have preamp outputs. Second, if you were to cut and splice RCA's and attach them to the factory speaker outputs, your voltage would be high. Probably too high for most amps. I recommend using a line level converter from soundgate. Its called ( LOC 4.4 ), very expensive but creates almost no engine noise. Now if you still want to bump up the voltave into your amp, check to see the max volt input of your amp is and then use a line driver. Phoenix gold makes a line driver, that ups your voltage to 9 volts. Some amps like a/d/s or JL Audio can actually take up to 16 volts. But thats sick loud and does not sound too good off a factory radio. Take it from me, use that LOC 4.4 and good RCA's, like high end Monster Cable and you won't regret it.

 

Actually, the factory radio does have preamplifier outputs. There is an external amplifier located underneath the factory radio that receives four low-level channels. The output from the amplifier is obviously speaker-level and the crossover clearly exists inside the factory amp (thankfully) since there are eight outputs from the factory amp and only four inputs!

I guess I will have to take apart my console and do the measurements... oh well, I hoped someone here would have done that already

-Alt

 

Even if the outputs from the factory radio are indeed lowlevel...you will still create noise without a line level converter. I did factory system upgrades for 6 years, using high end equipment like a/d/s, MB Quart, Nakamichi and so on. i have never been able to just attach rca's to a factory radio without creating some level of unwanted noise. and if you have this noise then pass it through a line driver, it will create even more and louder noise. but hey man, your car, your choice...just giving you opinion. I should be starting my system early next week, i will tell you how it goes.

 

If you're tapping into the line outputs how would a speaker-level to line-level converter be useful? There's no speaker level signal to convert...

The line driver will replace the factory amplifier. It will do effectively the same job as the amplifier, but is designed for a much higher load on the output. If the factory amplifier in that location doesn't amplify noise, the line driver won't either.

Using a speaker level to line level converter after the amplifier will force me to use factory Xover points, factory equalization, and will multiply the harmonic distortion in the system.

My original question pertained to the possibility that the line ouput voltage from the preamp may actually be high enough to preclude the use of a line driver at all, thus saving a little money and simplfying the installation.

-Alt

 

Well i will test mine in a few weeks, when i get started. If you get to it before me, just test the outputs from the radio and tell me what voltage they read. Alot of premium sound systems, for example the Monsoon system, has a small amp built into the radio before it even get the the premium amp. I have a feeling that this radio is the same way, just because it is not a leading name premium brand, like Bose or Harmonn Kardon and so on.

 

Yeah I also have this distinct feeling... everything so far in Acuras that I have tested has seemed overengineered. It wouldn't surprise me at all....

What kind of system are you setting up? I'm curious....

I'm going with Vifa 5.5" PL mids in ported enclosures in the doors, Scan-Speak Revelators (the new 12M's) in kicks, and Hiquphon OW-II tweeters next to them. Might add in some LPG tweeters in the stock locations to raise the soundstange as well...

Sub will be an Nd12.

thanks!
-Alt

 

Alt, wouldnt placing the lpg in the stock tweet location be bad because of reflection? unless alot of eq worked were to be done. I got the 25nfa and Im thinking im put them somewhere in the sidekicks. Tell me how your system turns out.

 

It might be a concern if I were using it as the primary tweeter but it will be a low-volume supertweeter effectively. Will be using a >5kHz Xover frequency.

There may still be reflection issues, so I may actually build angled pods into the stock holes. That said, the stock tweeters in the stock system dont seem to have too much harshness to them without any EQ at all, and since these effects reall vary from car to car, I'm not too worried about it.

That said, I do have an AudioControl DQX in the signal chain...

How do you like the 25nfa? I have yet to hear one but everything subjective I've read so far has intrigued me... I still am wary about using them as the main HF driver though... I dunno, feels weird running LPGs with Scan Revs I'm looking forward to the Hiquphons...

-Alt

 

i havent installed them yet as im waiting for my alto drive 30 to come in and do all my install at once. Ill listen to them in a few days when I sell one of my amps to a friend. ill post my impressions.

 

Nice... youre using an alto drive huh? I was considering one... might still get one if I need time delay. Does it do continuous phase adjustments too?

 

I will be running a/d/s 3series components up front and in the rear doors. 2 JL Audio 10w6v2's, a JL 300/4 for the fronts and rears, and a JL 500/1 running the subs. it should be a pretty good set-up. I have always done much more higher end and expensive systems in all my other cars. this time i want to just keep it simple, but shoudl still pull out some very high end sound quality

 

Sounds good man. Good luck on the install. I'm contemplating a spare tire well enclosure but I can't really commit myself to losing the spare... but then it's either lose the spare, or lose the benefit of folding rear seats. I need to figure out what's more important to me... what do you plan on doing?

 

i believe the alto has phase adjustments, it has MANy features....hehe Im going to fiberglass a 10 in the right corner of the trunk. there is no way im losing the spare or the fold down feature. i think a 12 would fit in there too. i had to sell the us amp 5600x cause its too big and i couldnt find a place to put it.
so now im going to run alto amps, those suckers are tiny and prolly fit under the seats.

 

Hmmm... how much are you getting the 30 for?

I should look into their amps too... going to their site now

Problem is, I need seven channels of amplification

 

Oooops... I meant LOWER load, not higher.

-Alt <---

 

Got it for 325. pretty good price....hehehe Decided on anything yet Alt?

 

Well I have all my drivers that I probably will end up using, but now I'm waiting for some test cabinets to be built so that I can start auditioning the configurations I'm considering (as well as the two tweeters I'm comparing).

325 is amazing... can I ask who you got it from? Damn I should have looked into those units...

-Alt

 

i got mine new with warrenty from an ECA member.

 

I see... interesting

How easy/difficult is it to use?

 

I havent installed yet...hehe

im not sure when i can install all this as im busy with school. I wanted to install during the break but my 6.5s didnt come in. my set up will be

lpg 25nfa
max fi 6.5 high qts
alto drive 30
alto 300.1 and 100.4

alt, my friend is doing a group buy and can get it around 300. Ill see if I can hook you up. I cant mention any names as im not sure if he would like that. ill keep you updated once i find out. he is going to be an authorized dealer so it would come w/ full warr. just email me if you need more questions. tuancdo@yahoo.com

 

did you install your system yet alt?

 

Nah... have a lot going on... want to sell my Z first before even touching the car. Did get some LPG 26NA's and 25NFAs to play with. I think I will not use the Hiquphons if I like the LPG's enough due to the size of the things...

I'm picking up some test enclosures this weekend to start auditioning the speakers...

 

Oh yeah, decided to use Scan 15W4531G00 midbasses in sealed enclosures instead of Vifa PLs ported... smaller enlcosure, more midbass, and better transient respose.

 

sweet...did you still need the alto 30?

 

Dunno... I might. it's basically a matter of whether I need time delay or not. How soon would I need to decide bro?

I'm looking at the specs again and it does look like a very useful tool for me as I just nocticed the subwoofer output which is something I am lacking on my DQX... guess I could sell that unit along with some other gear to get this one

Lemme know how soon I need to decide man (email me please)

thanks,
-Alt

 

So how about that head unit voltage at pre-amp? Anyone measure yet? I would do it, but heck, I am still waiting to take delivery of my TSX. May 19 cannot come soon enough!!!

Thanks!

 

What is your email Alt?

 

Just PMed you buddy...

 

I'm too busy these days to test the voltage... I will probably do that in a few weeks if no one else does, when I get my test enclosures and then I'll break out my oscilloscope.

sorry,
-Alt

 

So, gmfreed, if I also have OE radio interface history and had some successful noise-free experiences with no LOC used, are you gonna get all testy with me, too?

Xtant 3150 in a BMW w/factory head is one that came to mind. Used bypass caps to get rid of the DC offset, but no LOC. Surprised me too, but hey...

a/d/s amps have a long history of engine noise (I am an a/d/s/ speaker fan, and I've sold 'em and owned 'em, but I gotta say they are noisy... especially with the 642csi. Maybe we worked on too many Hondas )Also, LOC's decrease frequency response and do weird things to the phase relationships, so I don't want to use one in this instance.

I plan on doing a noise-free, LOC-free install in my fiancee's navi auto TSX. Planning it out now. Really interested in what altersys finds out. I plan on putting a test CD in and measing the OP with an oscilloscope, and I walso plan on testing with a spectrumanalyzer to see if the OP of the head unit is really flat, or if this supposed 40-Hz bump I hear about is in the head unit instead of the amp.

Peace, out.

 

Hey bud,
Great post... thanks for that. I am a lazy-ass and haven't gotten around to testing anything in the car at all. To be fair, I've been quite busy. I am putting my hobbies back at a higher priority so if I do in fact get around ot doing the tests i will post the results in a new thread for all to see.

If you get the numbers before me, please do the same (also if you could email me to let me know I'd greatly appreciate it). My method will be to use test tones and a scope since I don't yet have a spectrum analyzer available. Actually, getting voltage-vs-freq-vs-volume setting relationships can be even more useful than just a shape curve...

-Alt

 

OK< hate to drag this thread back into the light

Pulled apart the car today (bone-stock CG/Q 5AT Navi). Popped in the ol' CAN Alpine test disc, track 19, 1k sine wave. Set volume to 40. Measured at the amp, across the A1 Blue-Red and A8 Yellow wires (LF + and - from head unit to amp), with a Fluke Scopemeter.

296mV RMS, around 850mV (roughly) peak-to-peak. No clipping visible, which is nice.

Just for kicks, I did the same test on my old-school Alpine 7904. 306 mV RMS, 950 mV peak-to-peak.

So... it looks like this system is a bit light on the output level... in a perfect world, I probably shouldn't need a line driver, but it looks like I'll use one.

A buddy at Phoenix Gold is getting me an LD66 6-channel line driver. I'll install it in place of the factory amp and use it to drive 6 channels back.

(Oh, and yeah, I made sure that bal and fade were centered and bass and treble were flat

 

Oh, and the car was NOT running, so I suspect that when it is running the results are probably more like the Alpine 7904... which was on a 14.4V bench power supply.

 

Actually I doubt the line voltage will differ with the car running or not, given the regulated nature of line outputs.

Thanks for the specs!

-Alt

 

I decided to go straight out of the factory headunit and into an Audiocontrol EQS. From there right into the amps. The only issue I had was turn on pop and turn off pop. so i disconnected the remote turn on and switched the JL amps over to signal sensing and what do you know....no more turn on pop. I had no engine noise, but just a lttle noise caused by the EQS. Which is a stnadard problem in Audiocntrol pieces. But it was such a little noise issue I could tune it out at the amps.

I will agrre with you elduderino, a/d/s amp will cause engine noise, when not installed properly. I am not sure about the new ones, because they are the same technology as the Directed Audio amps, but the old ones needed a very short ground, reccommended 3-5 inches, or they made tons of noise.

As for the a/d/s speakers being "noisy", I am not sure what you are trying to say, but a/d/s speaker have great depth, and I have never delt with a better speaker. Their new design, since DEI bought them out, is wounderful. I actully think they sound better then they ever have.

 

I think you mis-understood my post - I wasn't clear. I was pointing out that (while I loved the speakers) the amps were noisy. I didn't actually mean to say that the speakers were noisy - sloppy writing on my part. I meant to highlight the word "speaker" but it gost lost in the other italics Sorry about that.

Hm... ever since a/d/s got rid of the US-made tweeter and started making the tweeter overseas, IMO they've never made it sound quite as good as it used to. But I'll pass along to my friend at Directed who manages the a/d/s line what you said - he'll be pleased.

Actually, they have had to drop the a/d/s car amp line due to slow sales. Speakers only now. New website should reflect that any day.

So what safety system did you use on your manual-tranny remote start?

 

Now that's interesting.... that a/d/s/ is dropping their amp line. Thanks for that info!

As for their speakers, I've never been a fan. One specific word always comes to mine whenI listen to a/d/s/ drivers (ranging from the low end all the way to the px's)- "hollow." That is, not just the quality of the sound, but the shape of it in space and in the soundfield. To each his own, because I know a lot of people that do favor their sound- and I've tried to accomodate them- but I can't get myself to like them at all.

Are you friends with JD?

-Alt

 

Yep. Hired him into DEI, actually. Had beers with him two weeks ago in San Marcos.

Mostly I liked the 325IS a lot.

 

just my sure confidence. I have been driving stick for over 10 years, and I have never left my cars in gear. I am very trusting with the emergency break. Probably not the safest way, but very effective for me. From what I understood with the a/d/s amps, they werent discontinued, they just mereged with the directed amps. They new design they used in their mids is great, the crossovers look awsome, but i can agree with the tweets. I do not like the new design, but when tuned up good, they do sound great. If anyone has the oppurtunity to listen to these speakers in a car, I would do so.