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Old 10th November 2010, 11:54   #10516
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Originally Posted by abhipuru16 View Post
So, there is no way to set HPF/LPF accurately (well, theoretically) with something like a DMM?
And by the way, my amplifier has a 12db/octave slope, it's fixed.
a scope might offer better readings again it is a slope not a cliff so one haas to figure out the 3db (half power) point.
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Old 10th November 2010, 12:10   #10517
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1. Is it an oscilloscope you're talking about?
2. DMM could be used only while setting gains?
3. If not, would my 80Hz 0db test tone method work?
4. What to check for in the readings?
5. I want to know if the phenomenon below is normal-

Quote:
Originally Posted by abhipuru16 View Post
Guys!

First of all, the equipment-

Velocity VPA4130 Amplifier
Fiesta Stock Headunit with Pre-outs taken from the Mainboard

According to the amplifier's rating of
4X130Watts RMS at 4Ohm
2X400Watts RMS at 4Ohm

I was aiming for 23V for front channel and 40V for the rear channel.

After that, I set the 50Hz 0db test tone on repeat and kept the volume to 75% of my headunit's maximum volume which is 34, that is, it was set at 24.
Now, while increasing the gains, their came a point where there was kind of a hilltop, after which, a further increase in the gains resulted in a decline in the voltage that the DMM showed.
When the volume was at 24 the hilltop came in at 20.xxV. Further increasing the gains resulted in a decrease in the voltage.

So, after a lot of tinkering around I frustratingly maxed the headunit's volume at 34 and then tried setting the gains. This time the maximum voltage I could achieve was 38.9V.


Now, during all this, the interesting thing I noticed was the gains were set quite low for both front and rear channel. Almost like 1/5th or 1/6th of the total.
The best part was that the gains for the front channel were set when the DMM read exactly 23V.
I am thinking, could I have further gained those 2V in the rear channels if I had set the volume to something like 30 or 32?

By the way, before proceeding with setting the gains, everything was set to a big "ZERO" both on the headunit and amp.

Is there anything wrong?
I am basically concerned with the

(i) "hilltop phenomenon" being normal or not and

(ii) my decision of maxing out the headunit's volume and in the process, maybe, I missed that particular volume where I could have gained 40Volts if I consider the hilltop phenomenon to be true?

Last edited by abhipuru16 : 10th November 2010 at 12:11.
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Old 10th November 2010, 16:06   #10518
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Experts:-

1. Your Car: Polo 1.6

2. Your current setup (If any): OEM Speakers in 4 doors + upgraded to a touchscreen HU with 3 RCA outs

3. Your Budget: 15k (for the first step)

4. Do you drive most of the time or is it chauffer driven? Only ME

5. Your Music preferences (Genres, favorite artists, etc.): Alternate Rock, Trance, bit of latest hip-hop and latest Hindi Songs

Additional Information:

6. Are you ready to sacrifice your boot space/modify door panels? : Not for the first step


Anyways for the first step i am thinking of putting only front comps and maybe a 4ch amp to power the front comps.I would use the remaining 2ch to power the sub which i may buy in the future.

My idea was to go for the best comps ~10k and a decent 4ch amp~ 5k.

I am not looking for very loud sound, i am mainly looking for clarity and a decent base(if possible). Just to give you an idea i was using pioneer T-2150 for the rear and stock speakers for the front in my corolla without an amp and i was quite satisfied.

Can you suggest me the best options. A few that i considered:-
Kicker 650.2 = 10k
Focal 165A = 8k
Focal 165vb Polyglass =11K
I have heard that theres a lot of fake focals around so please let me know if the prices are correct
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Old 10th November 2010, 16:27   #10519
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I have a very basic as well as silly question. Is it possible to have an ICE set up with only speakers and amplifier, so that an IPOd or such player can be directly connected,
with HU added later?

To add, I know nothing of the technicalities. Very basic understanding only.

Last edited by vamsi.kona : 10th November 2010 at 16:29.
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Old 10th November 2010, 20:34   #10520
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@abhipuru16, you could try borrowing an oscilloscope and a sweep generator (the oscilloscope can be triggered by its sweep ramp) to accurately calibrate the LPF/HPF! Not sure if the result obtained after calibration will be better or worse.

@shekaran, avoid the "18 farad" capacitor - it will not make any difference with the equipment you are putting in. BTW, how much is the 9" LCD/DVD player? Which make?

Quote:
Originally Posted by spyking View Post
The HU is a Nippon unit and does not come with pre-outs. ...
Then you definitely need an LoC.

Quote:
Originally Posted by spyking View Post
Would you suggest some good budget amps?
... what would be the models to look for? ...
Haven't heard Bull components - not sure if they are bright or not.

For amps, there are JBL, Blaupunkt, Auditor, Kenwood, Pio, even Sony.

For components, try JBL/Infinity, Auditor, Blaupunkt, Boston, Bull, Illusion, ... make sure you audition the speakers before you buy any.

Last edited by DerAlte : 10th November 2010 at 20:55.
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Old 10th November 2010, 23:51   #10521
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DerAlte Sir,
@shekaran, avoid the "18 farad" capacitor - it will not make any difference with the equipment you are putting in. BTW, how much is the 9" LCD/DVD player? Which make?
the 9" LCD/DVD is worldtech brand costing 8k,
and installers in my city use a min of 1Farad Capacitor, for amps driving the sub, quoting that the bass would not be compromised. i know that 18F is overkill, but a friend from USA brought it, Boss Audio make for 5.5k - which seemed a steal price to me.
Gurus, pls help me on finalising what are all the cables i need to use in my ICE, as i am technically not well versed in this audio subject.
Happy/Safe Motoring, Cheers.
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Old 11th November 2010, 09:51   #10522
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Thanks, @shekaran-anna. Well, it is the installers who are making some money at the cost of the consumers. It is only an assumption that "bass would not be compromised" - no one can really make out the difference unless one does elaborate SPL tests.
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Old 11th November 2010, 09:58   #10523
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I am trying to decide between Infinity REF 6030 and Polk Audio db6501 compo's. I am personally yet to hear them both, but wanted any review's/inputs between the two.
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Old 11th November 2010, 10:40   #10524
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Thanks, @shekaran-anna - BY DERALTE
Actually i am not old, just 35 years Young, so you can call me shekar itself pls...
Audio Installers say that Capacitor will come when sudden bass needs 12Volts current standard - which maynot be always possible with alternator running at low rpms. i dont know whether this fact is true or not, but found out that one of my friends swift had headlight dimming problems at nights @ medium to high ICE volumes, which was not the case after a 3Farad cap was installed before the amp.
Regards.
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Old 11th November 2010, 13:22   #10525
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The capacitor helps the light dimming problem much more than the power output problem. Light bulbs are more sensitive to voltage fluctuations, and eyes sense these fluctuations much more especially at night when the contrast is higher. An amp, on the other hand, has an in inbuilt voltage regulator, which keeps the internal voltages (more than +/-30V usually) regulated to +/-10% or better based on input voltage and current drawn. 12V line voltage fluctuation of 0.3V is visible on the headlamps - the amps are not even tickled at that level.

At 10V or less (like what it dips to when cranking the engine), the headlamp output falls to candle-illumination levels. Even the amp would not be able to regulate well at that level, but then a capacitor is absolutely useless under such circumstances. A capacitor works well in short bursts of 100-300milliseconds, anything more it will discharge once and do nothing unless it gets another 1 second to charge. You do the maths!
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Old 11th November 2010, 15:32   #10526
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Quote:
Originally Posted by abhipuru16 View Post
1. Is it an oscilloscope you're talking about?
2. DMM could be used only while setting gains?
3. If not, would my 80Hz 0db test tone method work?
4. What to check for in the readings?
5. I want to know if the phenomenon below is normal-
1. yes
2. yes but if you want to set your XO to 3db a scope is easier to use
3. unless you have a scope how do you the generator is making 80Hz and not 88Hz or some other frequency
4. P-P voltage
5. Not uncommon but why do you ask?

Quote:
Originally Posted by shekaran View Post
and installers in my city use a min of 1Farad Capacitor...Gurus, pls help me on finalising what are all the cables i need to use in my ICE, as i am technically not well versed in this audio subject.
The Cap will do little for your audio. As DA has said it might do a little for the head light dimming. It is better to invest in power wiring. Google "BIG 3 wiring" and you will get a lot of info on this.

Quote:
Originally Posted by praful View Post
I am trying to decide between Infinity REF 6030 and Polk Audio db6501 compo's.
The 2 components are very dis-similar. The 6030 is sorta laid back the Polk are more upfront.

Quote:
Originally Posted by shekaran View Post
Capacitor will come when sudden bass needs 12Volts current standard... which was not the case after a 3Farad cap was installed before the amp.
Regards.
Like said it was only the headlight dimming that was solved. The audio has little use for the cap in most cases. All GOOD amps have enough caps inside them (post rectification).

Quote:
Originally Posted by DerAlte View Post
An amp, on the other hand, has an in inbuilt voltage regulator, which keeps the internal voltages (more than +/-30V usually) regulated to +/-10% or better based on input voltage and current drawn.

At 10V or less (like what it dips to when cranking the engine), the headlamp output falls to candle-illumination levels. Even the amp would not be able to regulate well at that level, but then a capacitor is absolutely useless under such circumstances. A capacitor works well in short bursts of 100-300milliseconds, anything more it will discharge once and do nothing unless it gets another 1 second to charge. You do the maths!
To add to what DA has already stated aove most run of the mill amps are rated at 14.4V and 12.5V. Some at 13.8V and 12V. Few at 11V and a few amps will still put out their rated wattage at 10V.
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Old 11th November 2010, 20:39   #10527
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I just read somewhere on Google that to set the gains at 80Hz we may use a 60Hz tone and try to "High Pass" or "Low Pass" until it is heard?
Is it true?
Is it because of the 12db/octave slope?


What would be the best way to set the crossovers at 80Hz?
My amplifier has no intermediate markings.
I only see 65Hz as minimum and 4000Hz as maximum.
Also, the subsonic filter needs to be set.
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Old 12th November 2010, 01:13   #10528
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Today, I am gonna take another shot in tuning my Velocity Amplifier.
Which db test tone do you suggest?
Also, what all frequency?

I mean, for fronts-
1kHz 0db or -3db or -5db or -10db?
Similarly, what test tone should I use for tuning the Sub-stage?

Please suggest some trusted sites to download these from as well, I used 50Hz 0db and 1kHz 0db test tone until now which were downloaded from Realm of Excursion.
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Old 12th November 2010, 10:57   #10529
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Quote:
Originally Posted by navin View Post
The 2 components are very dis-similar. The 6030 is sorta laid back the Polk are more upfront.
Navin, could please elaborate more in layman terms?

I understand the two attributes when in context of humans, but for speakers I don't get it!

I am basically looking at a versatile setup, as there is no specific kind of music I listen to. Everything from bollywood, hiphop, rap, trance, rock everything goes!
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Old 12th November 2010, 11:28   #10530
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Quote:
Originally Posted by abhipuru16 View Post
Which db test tone do you suggest?
Also, what all frequency?
1kHz 0db or -3db or -5db or -10db?
Similarly, what test tone should I use for tuning the Sub-stage?

Please suggest some trusted sites to download these from as well, I used 50Hz 0db and 1kHz 0db test tone until now which were downloaded from Realm of Excursion.
50Hz and 1kHz are fine as long the sub is XOed atleast an octave above 50Hz.

Quote:
Originally Posted by praful View Post
I understand the two attributes when in context of humans, but for speakers I don't get it!
Polk = more HF, Infinity = less HF. Pick your poison.

Quote:
Originally Posted by abhipuru16 View Post
I just read somewhere on Google that to set the gains at 80Hz we may use a 60Hz tone and try to "High Pass" or "Low Pass" until it is heard?
Is it true?
Is it because of the 12db/octave slope?
What would be the best way to set the crossovers at 80Hz?
My amplifier has no intermediate markings.
I only see 65Hz as minimum and 4000Hz as maximum.
Also, the subsonic filter needs to be set.
Why not just tune by ear and leave it at that.

I'd XO as low as possible for the front midbass drivers. So play your music at your normal volumes with no XO settings and then tune the XO to roll off at say 100Hz/12db for the front drivers and slowly reduce that frequency till you hear your midbass strain then back of a bit. This is as low as you would want your midbass drivers to safely play. You subwoofer just fills is for what left so if your midbass drivers can go as low as 80Hz/12db the subwoofer can be XOed at 80Hz/12db too. You can even try a little overlap (not more than 1/3rd octave so yo can XO your midbass @80Hz and your sub a@ 100Hz).

GTO, for example, spent 7 months tuning his car to sound just right and he is not even a real "ICE VICE" guy. Tuning is a matter of patience and careful listening.
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