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View Full Version : measured my 9815 pre-outs... (opinions?)



Slaugh
10-27-2005, 05:16 PM
playing a 60hz sine wave@0db with the RCAs connected to my amplifier i got these results... hu volume maxes out at 35 and bass at +6db... MX is a ****** loud but boosts the bass region so i could measure the differens with and without it...

Sub-w Out +15, Volume 35, FLAT = 4.1v
Sub-w Out +15, Volume 35, Bass +6 = 4.8v
Sub-w Out +15, Volume 35, Bass +6, MX 3 = 5.3v

now using sets people use daily to listen to music

Sub-w Out +12, Volume 25, FLAT = 0.3v
Sub-w Out +12, Volume 25, Bass +3 = 0.6v
Sub-w Out +5, Volume 20, Bass +3 = 0.0v

what do you think? do you think this HU really has 4v preouts? knowing we'll never get to see any voltage any close to this under normal use... any conclusion on this?

JimJ
10-27-2005, 05:17 PM
do you think this HU really has 4v preouts?

What kind of a question is that? You saw the results for yourself, you know that the only way this deck reaches full preout voltage is at full volume.

That's just what it is.

Slaugh
10-27-2005, 05:30 PM
What kind of a question is that? You saw the results for yourself, you know that the only way this deck reaches full preout voltage is at full volume.

That's just what it is.
yeah, but is that the way all the hus should be? not even a decimal of voltage at volume 20 and 0,3v at volume 25 with sub-out +12???

i think it's pointless to anounce it as having 4v preout, since no one hipotethically will be reaching this voltage listening to music...

well so, is that how HU's work? do they only reach their announced preout voltages at the top volume??

i'd like to see Eclipse, Pioneer and other hu's preouts results... can you show me some? i think it's voltages are too weak below vol 25

ToyTundra
10-27-2005, 05:59 PM
i'd like to see Eclipse, Pioneer and other hu's preouts results... can you show me some? i think it's voltages are too weak below vol 25

Me too, but i'm too lazy to pull mine out :(

azbass
10-27-2005, 06:29 PM
i'd like to see Eclipse, Pioneer and other hu's preouts results... can you show me some? i think it's voltages are too weak below vol 25

i was at a Kicker meeting, and the guys there talked about a lot of HU preout measureing they did on different HU's. eclipse was the only deck that put out its true or more voltage, etc. everyhting else was below rated, which is usually the case.

Slaugh
10-27-2005, 06:34 PM
Me too, but i'm too lazy to pull mine out :(
u dont have too.... just disconnect the subwoofer rca cable connected to your amp and measure the voltage on it....

to make it more precise you should have a resistive load of 10k ohms on this RCA, but the difference is minimal (i tested and i afirm this)

you need a 60hz sinewave@0db

AVSTANG02
10-27-2005, 06:35 PM
Yah so what does this all mean?

azbass
10-27-2005, 06:38 PM
Yah so what does this all mean?

nothing just a bunch of garbage.

DBfan187
10-27-2005, 06:42 PM
what do you think? do you think this HU really has 4v preouts? knowing we'll never get to see any voltage any close to this under normal use... any conclusion on this?4v, sure. But you won't get it before clipping. HU's are made this way so you can get linear usage of the volume knob.

Would you rather turn the knob to volume 2 and have the amp @ full power?
Or would you like to be able to use the entire volume range?

Slaugh
10-27-2005, 06:44 PM
4v, sure. But you won't get it before clipping. HU's are made this way so you can get linear usage of the volume knob.

Would you rather turn the knob to volume 2 and have the amp @ full power?
Or would you like to be able to use the entire volume range?
i know i just wish i could adjust my gains to match max output at volume 25... i get ground noise and distortion from the HU after this volume...

oh and the above post doesn't include you... :D

DBfan187
10-27-2005, 06:47 PM
try getting ahold of an oscope to see where it's clipping.

Johnny Drama
10-27-2005, 06:48 PM
i was at a Kicker meeting, and the guys there talked about a lot of HU preout measureing they did on different HU's. eclipse was the only deck that put out its true or more voltage, etc. everyhting else was below rated, which is usually the case.

I tested mine a while back and was getting 10.6v I didnt have an o-scope to mesure clipping.

Johnny Drama
10-27-2005, 06:50 PM
wrong thread...

DBfan187
10-27-2005, 08:16 PM
here (http://www.caraudio.com/vb/showthread.php?t=118217)

ToyTundra
10-27-2005, 09:04 PM
So i did the test:
Eclipse CD-3434
60Hz 0dB sine wave
Vol 59/80 is the loudest unclipped level
Sub out=16/16........Vol 80/80.......bass flat.......2.69V
Sub out=16/16........Vol 80/80.......bass +6/6.....Too clipped I won't test
Sub out=10/16........Vol 80/80.......bass flat.......1.84V
Sub out=10/16........Vol 59/80.......bass flat.......0.24V

DBfan187
10-27-2005, 09:06 PM
So i did the test:
Eclipse CD-3434
60Hz 0dB sine wave
Vol 59/80 is the loudest unclipped level
Sub out=16/16........Vol 80/80.......bass flat.......2.69V
Sub out=16/16........Vol 80/80.......bass +6/6.....Too clipped I won't test
Sub out=10/16........Vol 80/80.......bass flat.......1.84V
Sub out=10/16........Vol 59/80.......bass flat.......0.24Vyou use an oscope?

I also have a CD3434 and a oscope, mine was 74/80 voltage was 1.7v.

Slaugh
10-27-2005, 09:09 PM
here (http://www.caraudio.com/vb/showthread.php?t=118217)
the 7893 had stronger voltages than my 9815...

ToyTundra
10-27-2005, 10:26 PM
you use an oscope?

I also have a CD3434 and a oscope, mine was 74/80 voltage was 1.7v.

No oscope, just a DMM. I used a 0dB wave

DBfan187
10-27-2005, 10:30 PM
so was mine. I used a 1kHz 0dB tone on my nonfading preouts which emits a full range signal(+16).

DBfan187
10-27-2005, 10:37 PM
also, how in the hell can you tell if it's clipped when using a DMM?

ToyTundra
10-27-2005, 10:47 PM
^^ my door speakers were still plugged in so i could hear some of the Tone through them

DBfan187
10-27-2005, 10:49 PM
ah, makes sense,

:( You put your speakers life on the line.

ToyTundra
10-27-2005, 10:54 PM
True. I owe them now. Maybe i'll find some horns they can hump or somthing

DBfan187
10-29-2005, 03:06 PM
ok, just measured my front, rear preouts with the oscope.

1kHz 0dB

NO CLIPPING @ FULL VOLUME!

:woot:

But the nonfader clips @ volume 74 with it on +16.

AVSTANG02
10-29-2005, 04:07 PM
Slaugh is never gonna get a clue.

DiamondFanatic
10-29-2005, 04:15 PM
Slaugh is never gonna get a clue.
Yeah he apparently really hates being able to adjust his volume level.

fuzzai
10-30-2005, 12:40 PM
Yeah he apparently really hates being able to adjust his volume level.
Wait till he relizes his amps don't produce the 500wrms predicted at 14.4 volts on 25 volume. lol

killcrap
11-01-2005, 08:29 AM
correct me if i'm wrong, but if i recall correctly, when the manufacturer advertizes 4v, they always mean 4vMAX, not 4vRMS

3.5Max6spd
11-01-2005, 11:43 AM
correct me if i'm wrong, but if i recall correctly, when the manufacturer advertizes 4v, they always mean 4vMAX, not 4vRMS

Correct, and voltage is delivered in an algorithmical fashion...doesnt mean that at half volume you'll see half total rated voltage

thch
11-01-2005, 12:33 PM
you are correct.

typically you will have a 1-3dB change per click.
-1db = 0.89
-5dB = 0.56
-10dB = 0.32

depending on the hu, you might be able to determine where clipping occurs by plotting the volume settings vs log(V). you would assume you'd have straight lines anytime the voltage inceased logritmically (by 1dB or 2dB per click). but if there were clipping, you would meause less of a change.

Slaugh
11-01-2005, 12:56 PM
well guys sorry to ask this, but then what is all that bullshit about setting the player to Flat and with it on 75% of it's total volume start increasing the Gain until it starts to distort and then go back until the distortion is gone?

i see this absolutely in all gain setting tutorial i've read... so what's the purpose of this?

DBfan187
11-01-2005, 01:42 PM
to get the, cleanest, undistorted, balanced signal to your amps inputs.

Slaugh
11-01-2005, 04:17 PM
and what is the explanation why it's exactly where the THD starts to increase faster? that's exactly what i want to do and you guys are picking on me for what reason then?

DBfan187
11-01-2005, 04:47 PM
the object of the game is to have everything in the signal chain to clip @ the same time. that way you can enjoy the use of your volume knob.

noob with an RS
11-01-2005, 05:30 PM
im tired of reading through your HU threads slaugh the point is even if your alpines maximum voltage was 2 volts at full volume you could have your amps gain higher than it would need to be with the 4 volt pre out and youll still have the same sound form your system stop blaming your HU for having a system that sounds like *** u either need to learn to tune it or shut the fucc up have a good day just kidding im being sarcastic you *******

fhlh
11-03-2005, 06:15 PM
i know i just wish i could adjust my gains to match max output at volume 25... i get ground noise and distortion from the HU after this volume...

oh and the above post doesn't include you... :D

how is the HEADUNIT grounded? Thru the car's harness?
If so, find another ground. This solved the noise on my old alpine 9813.