Hi guys/gals,
I'm having a bit of a problem. In order to set my amp gains properly,
I'm supposed to set my HU volume at around 75-80%. Well I have a
factory Nissan Altima HU that has no indicators whatsoever of volume
level or percentage of volume.

All I have is a knob with notches. There is no beginning and no end, and
the notches don't seem to be perfectly uniform.

The other day I put a thin piece of tape on the knob and tried to measure
how far it would turn before it sounded as if it was maxing out.
I found out that this measurement varies greatly depending on the loudness
of the source:

AM radio: I can turn it almost 360 degrees
FM radio: 230 degrees
CD, quiet track: 200 degrees
CD, loud track: 170 degrees

So how do I determine where 75% of my volume level is if each source
requires me to turn it to a different level to achive a certain loudness?

I've already blown a couple of subs due to improperly set gains so is
there any way of figuring this out? Is there a way to determine this with
a multimeter or anything?

I really don't want to spend 150-200 bucks on a new HU just to get a
volume level indicator.

Any advice would be greatly appreciated,
Don

Forget using a certain percentage, such as 75-80% and do this:

Turn the amp gain all the way down. Turn the HU volume up all the way until
the music starts to distort and then back it off until the distortion goes
away. Then do the exact same thing with the amp gain. Done. Choose a very
dynamic CD recording. I would also turn the bass & treble controls to flat.

The 75-80% is just a reference, but by using the above procedure it really
doesn't matter if it's 78% or 89%.

Tony


--



What's more likely? That an all-powerful mysterious god created the
universe and then decided not to give any proof of his existence? Or, that
he simply doesn't exist at all? And that we created him so that we wouldn't
have to feel so small and alone. -Eleanor Arroway, Contact

"Don Joe" wrote in message
news
Hi guys/gals,
I'm having a bit of a problem. In order to set my amp gains properly,
I'm supposed to set my HU volume at around 75-80%. Well I have a
factory Nissan Altima HU that has no indicators whatsoever of volume
level or percentage of volume.

All I have is a knob with notches. There is no beginning and no end, and
the notches don't seem to be perfectly uniform.

The other day I put a thin piece of tape on the knob and tried to measure
how far it would turn before it sounded as if it was maxing out.
I found out that this measurement varies greatly depending on the loudness
of the source:

AM radio: I can turn it almost 360 degrees
FM radio: 230 degrees
CD, quiet track: 200 degrees
CD, loud track: 170 degrees

So how do I determine where 75% of my volume level is if each source
requires me to turn it to a different level to achive a certain loudness?

I've already blown a couple of subs due to improperly set gains so is
there any way of figuring this out? Is there a way to determine this with
a multimeter or anything?

I really don't want to spend 150-200 bucks on a new HU just to get a
volume level indicator.

Any advice would be greatly appreciated,
Don

http://www.installer.com/tech/gains.html

it doesnt have to be 75% , just estimate it ...

Don Joe wrote:

Hi guys/gals,
I'm having a bit of a problem. In order to set my amp gains properly,
I'm supposed to set my HU volume at around 75-80%. Well I have a
factory Nissan Altima HU that has no indicators whatsoever of volume
level or percentage of volume.

All I have is a knob with notches. There is no beginning and no end, and
the notches don't seem to be perfectly uniform.

The other day I put a thin piece of tape on the knob and tried to measure
how far it would turn before it sounded as if it was maxing out.
I found out that this measurement varies greatly depending on the loudness
of the source:

AM radio: I can turn it almost 360 degrees
FM radio: 230 degrees
CD, quiet track: 200 degrees
CD, loud track: 170 degrees

So how do I determine where 75% of my volume level is if each source
requires me to turn it to a different level to achive a certain loudness?

I've already blown a couple of subs due to improperly set gains so is
there any way of figuring this out? Is there a way to determine this with
a multimeter or anything?

I really don't want to spend 150-200 bucks on a new HU just to get a
volume level indicator.

Any advice would be greatly appreciated,
Don

Hi Eddie,

I read your gain page a few weeks ago. Thanks for the information. I
guess I don't have much ability to set my gain by ear because I've already
blown two IDQ12s with improperly set gains. At no point did I ever hear
any distortion so it's kind of a mystery as to why they broke.
I have one working sub left at the moment and used the multimeter method
to set the gain for it. The others I believed I had set correctly by ear
(and even backed off a little from that point) but I guess not.
I'm kind of tired of being constantly paranoid about a certain bass note
being too loud and doing in my sub(s). I've yet to really enjoy my system
because of the constant worrying. I'm thinking of getting an MTX 801D
which has an anti-clipping circuit.

Anyway... Thanks for the info, guys.

Don

On Thu, 15 Jul 2004 16:59:04 +0000, Eddie Runner wrote:

http://www.installer.com/tech/gains.html

it doesnt have to be 75% , just estimate it ...

Don Joe wrote:

Hi guys/gals,
I'm having a bit of a problem. In order to set my amp gains properly,
I'm supposed to set my HU volume at around 75-80%. Well I have a
factory Nissan Altima HU that has no indicators whatsoever of volume
level or percentage of volume.

All I have is a knob with notches. There is no beginning and no end, and
the notches don't seem to be perfectly uniform.

The other day I put a thin piece of tape on the knob and tried to measure
how far it would turn before it sounded as if it was maxing out.
I found out that this measurement varies greatly depending on the loudness
of the source:

AM radio: I can turn it almost 360 degrees
FM radio: 230 degrees
CD, quiet track: 200 degrees
CD, loud track: 170 degrees

So how do I determine where 75% of my volume level is if each source
requires me to turn it to a different level to achive a certain loudness?

I've already blown a couple of subs due to improperly set gains so is
there any way of figuring this out? Is there a way to determine this with
a multimeter or anything?

I really don't want to spend 150-200 bucks on a new HU just to get a
volume level indicator.

Any advice would be greatly appreciated,
Don

I read your gain page a few weeks ago. Thanks for the information. I
guess I don't have much ability to set my gain by ear because I've already
blown two IDQ12s with improperly set gains. At no point did I ever hear
any distortion so it's kind of a mystery as to why they broke.

Speakers don't always distort before blowing. And people often don't hear
them distorting at such loud volumes anyway. A lot of the time you'll smell
them before you hear them.

I have one working sub left at the moment and used the multimeter method
to set the gain for it.

There's a multimeter method?

The others I believed I had set correctly by ear
(and even backed off a little from that point) but I guess not.
I'm kind of tired of being constantly paranoid about a certain bass note
being too loud and doing in my sub(s).

Buy some subs with better power handling then. Or, do as I do, and just buy
backups. Paranoia is one way to ruin the experience.

I've yet to really enjoy my system
because of the constant worrying. I'm thinking of getting an MTX 801D
which has an anti-clipping circuit.

What's an anti-clipping circuit? Does it indicate when you're clipping, or
does it actually back off on the volume for you when you're clipping?

"MZ" wrote in message
...


What's an anti-clipping circuit? Does it indicate when you're clipping,
or
does it actually back off on the volume for you when you're clipping?



Got one of these in it set up as a max output comparator. Could also be a
variant of this device but these seem to be most popular/reliable:

http://www.eletrica.ufpr.br/lamar/te...ets/LM3080.pdf

They do work well until you overload the front end or exceed LV rail
voltage.

It looks at the output waveform and compares it to the input just before the
voltage gain stage. If it sees a difference other than gain it lowers the
gain in an instant and releases it. It holds as long as there is a waveform
difference.

quite novel compared to a fixed limiter because if the rails sag as would
happen in low impedance conditions the clip limiting is still effective.

Chad

Peavey has it as DDT
Crest has it as TCP (tour class protection)
Crown has it as IOC (have to buy external PIP card for limit)

Used all over!

I read your gain page a few weeks ago. Thanks for the information. I
guess I don't have much ability to set my gain by ear because I've already
blown two IDQ12s with improperly set gains. At no point did I ever hear
any distortion so it's kind of a mystery as to why they broke.

You wont blow speakers with an improperly set gain....

A properly set gain would let the amp play FULL POWER, so unless you set
the gain so low the amp wont work right, the gain controls have nothing to do
with why you blew your woofers...

Your amp may have a problem with it...
Your speakers may have had problems...
Your hookups could have been wrong...
Your woofers could have been out of phase requiring alot more power
for a low amount of bass....

Worrying about your gain controls, I think your on the wrong track to
find your real problem..

Eddie Runner

Eddie Runner wrote:



I read your gain page a few weeks ago. Thanks for the information. I
guess I don't have much ability to set my gain by ear because I've
already
blown two IDQ12s with improperly set gains. At no point did I ever
hear any distortion so it's kind of a mystery as to why they broke.

You wont blow speakers with an improperly set gain....

A properly set gain would let the amp play FULL POWER, so unless you set
the gain so low the amp wont work right, the gain controls have nothing to
do with why you blew your woofers...

Your amp may have a problem with it...
Your speakers may have had problems...
Your hookups could have been wrong...
Your woofers could have been out of phase requiring alot more power
for a low amount of bass....

Worrying about your gain controls, I think your on the wrong track to
find your real problem..

Eddie Runner

All true. Another thing to consider -- just how powerful is your amplifier,
and how much power are the speakers rated for? You may simply be
overpowering the speakers.

Scott Gardner