[navin]

Originally Posted by angelfire

Headnit is pio 5650..with 2rca preouts..
Front channel from the amp is connected to Jbl gto427`s with HPF on at 80 hz
Rear channel from the amp is connected to pio 2090`s...With LPF off

Now when i turn on the NONFAD...there is Output from the rear speakers...
With the NOFAD off..There is no output from the rears...

So either you can use the Non Fad on and have no fading or use the non fad off and have no rear output. Not a nice choice.

It does seem that the HU is swtching the rear output off when non fad is off. I am surprised that the manual says (and the HU behaves similarly) that when Non fad is on the internal LPF is bypassed. Seems like the only way you will get fader and rear output is by using the HU's amp to drive the rear speakers and using the Non fad on output to drive a sub.

[hydrashok]

Originally Posted by navin

Seems like the only way you will get fader and rear output is by using the HU's amp to drive the rear speakers and using the Non fad on output to drive a sub.

It looks odd to me too . Probably that HU is meant to drive a front + sub type of system.

Another (expensive ) option would be to split the front pre-out (the full range pre-out) to the front & rear channels of a 4-ch amp, and send the non-fade pre-out to a mono amp and drive the sub with that mono amp. But again, the "Fader" option in the HU will be useless. Any front-rear balance will have to be done with the front channel & rear channel gains in the 4-ch amp.

[navin]

Since the rear is for rear fill only driving the rear from the HU seems a nicer option esp since you retain fading.

[hydrashok]

Originally Posted by navin

Since the rear is for rear fill only driving the rear from the HU seems a nicer option esp since you retain fading.

Yep, everything considered, this seems to be the best option. And this is something that can be setup with a quick visit to the installer.

[angelfire]

Originally Posted by hydrashok

Yep, everything considered, this seems to be the best option. And this is something that can be setup with a quick visit to the installer.

But then guess i`l lose out some bass from the rears right...Wil try that anyways...All i want is good sound stage upfront
another option is reducing the gains on the rear channel...Wil doing so affect the SQ?..
edit..My front speaker`s have a frequency range of 90hz-20khz...Nd the hpf on my amp is 80hz...do i need to add a seperate hpf circuit to prevent disortion??..

[shyamhegde]

Thanks for the answers to my queries. Feels good when you said my plan toward ICE is in right direction. Will plan/budget this project accordingly considering all your suggestions and will keep you posted once I start. (Vitamin M is the key)

Sam-jee, I know there is no need to bribe here for helps! : ) I respect you all and I am sincere appreciating you all. (I know You were just kidding though)

I have couple of doubts on my mind -

1. What is *damping* (coz it is costing noticeable money too). I did not see any specific discussion/info on the section (I might have missed also) but if somebody could throw some light on this....

2. I read many times - having rear speakers on tray is not recommended. (I can’t have speaker box on the boot - will go for subwoofer tube/ported box which can be detachable on demand though) But is there any way we can still have tray and minimize the bad results of that?

[Bass&Trouble]

Originally Posted by angelfire

But then guess i`l lose out some bass from the rears right...Wil try that anyways...All i want is good sound stage upfront
another option is reducing the gains on the rear channel...Wil doing so affect the SQ?..
edit..My front speaker`s have a frequency range of 90hz-20khz...Nd the hpf on my amp is 80hz...do i need to add a seperate hpf circuit to prevent disortion??..

I was not able to read all your posts, but non-fading pre-out is one where the level can be adjusted, but it cannot be adjusted by changing fader settings. Now, if your rear speakers are connected to the non fading pre-out through the amp, then they will not fade when you use the fader; the level of the rear speakers can be adjusted using the non-fading level setting, and you can switch it off completely by turning the non-fad off. All this is applicable ONLY for the pre-out. If you connect rear speakers to the rear speaker outputs of the head unit, then they will fade normally and will not turn off when you switch the non-fading pre-out off.

If the rears are overpowering, lower the non-fading pre-out level, or trim the gain on the amp.

What front speaker do you have? If it's a 4" 80Hz is not too bad. If you have anything larger than that (the speaker, not you literally ), then that's a very bad frequency response. Get a new one! On a serious note, not very practical to add another crossover, unless its like a bass blocker. But 80 Hz is ok, just live with it till you get an amp with variable crossover frequency.

[Bass&Trouble]

Originally Posted by elf

@Sam: How kind of you to offer. I've always wanted my bottom end tweaked by a yeti. And this one drives a Cadillac & promises to tweak it hard. I'm blessed.

I do hope that you remember that more importantly, this is a public forum & that less importantly, the both of us have better halves, so this will have to go into the covert operations arena of our relationship. Am also looking forward to having Bass&Trouble fiddle with my controls if he's so inclined.

I'd tweak your bottom end any time you want. But certainly not after the yeti has paid a visit. The Yeti supercedes me in settings. And once the Yeti sets things, I'm sure they'd be pretty irreversible. Very loose base, he must be capable of setting.

[navin]

Originally Posted by shyamhegde

1. What is *damping* (coz it is costing noticeable money too). I did not see any specific discussion/info on the section (I might have missed also) but if somebody could throw some light on this....

most car manufacturers and designers dont give a hoot for ICE atleast not good ICE besides metal tends to resonate/ring rather easily. damping is applying sound absorbing material to these doors and panels (trunk, roof) to reduce this resonance/ringing.

The reason it is expensive is
a) there are very few companies specialising in making damping material that is easy to apply and effective for cars.

b) Very few of us are willing to experiment with alternates becuase our cars will be out of commision while we are experimenting and becuase we just dont have the time. Remember alternates must not only damp well but also survive a few years in what can be a rather harsh (hot and humid) envroment. A parked car in summer can have internal temps exceeding 100 deg F. Certain grades of sponge rubber/foam can also be used (instead of the branded products) but their availabilty is suspect and applying them requires more skill as they dont have a pre-adhesive surface.

[elf]

Originally Posted by navin

... Certain grades of sponge rubber/foam can also be used (instead of the branded products) but their availabilty is suspect and applying them requires more skill as they dont have a pre-adhesive surface.

So for damping, can Heatlon be used after gumming one side with rubber solution (Bosch-stik) & sticking it to the inside of the body panels? I've got some 1 inch thick sheets installed below my spare wheel cover in my boot & that came quite cheap. Different thicknesses (~3) are also available.

Just trying to figure out a cheaper alternative to the 10-12k damping estimates I've seen bandied about here...

[Sam Kapasi]

It's what I used to use, 10 years ago when things were difficult to buy. Jhat Pat and Heatlon.

[Bass&Trouble]

Originally Posted by elf

So for damping, can Heatlon be used after gumming one side with rubber solution (Bosch-stik) & sticking it to the inside of the body panels? I've got some 1 inch thick sheets installed below my spare wheel cover in my boot & that came quite cheap. Different thicknesses (~3) are also available.

Just trying to figure out a cheaper alternative to the 10-12k damping estimates I've seen bandied about here...

Foams are no good at damping bass. To damp bass, the damping material should be viscous. Heatlon, or any other such low density foam will not be of any help. They'll probably just keep the door compartment cooler. Also, I have seen some people use open celled urethane foams for damping. These retain water, and the end result is corrosion of the metal to which the foam is adhering.

[elf]

Thank yee, kind sirloins for thine mosht valuables advices.

[navin]

Before Dynamat and co became available I used 1.5mm think lead sheet (there was a place opposite Pydhonie Police Station that sold this). The only problem was that it took me almost 40kgs of this stuff to damp my Contessa (1989-90) 4 doors, the trunk, the hood (yes I even damped the hood with lead and heatlon), the rear shelf and the subwoofer cabinet (it was a tranny line). I was lot more "involved" in ICE then.

There are certain grades of sponge rubber (used to some by Hindustan Rubber) having a Shore hardness of 40 and temp capabilies in excess of 100deg F that I have also used. I dont remember the details and the car on which I used it is long sold. I even used this rubber under the seat to damp some of the sound. Now this was a time when I had installed Aura Bass Shakters in the back rest and seat. Gives you an idea how much I used to experiment. Today everyone wants a tried and tested solution.

There I go talking like an "old man" again.

[sk456]

I have Hertz 3 way comps on the front doors and a sealed IDQ 10" sub in the trunk... I drive a santro xing... althogh I have some damping doen on the front doors...( I think i have a couple of sheets of dynamat tucked in soemwhere )...but a lot more is required...

Would I need to damp rear doors as well...? ( Im not a bass head...hear vocals/jazz/classical/rock)... from what ive read so far:

I would need good damping on the :

• Front doors:
• Boot
• Number plate

Where else would I need damping for a "well damped " solution wihtout going over board on it.
Would any damping be needed on the floors as well ? I mean will that make a difference in SQ?